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| Publications of Miguel A. Nicolelis :chronological alphabetical combined listing:
%% Journal Articles
@article{fds364108,
Author = {Fonoff, ET and Edgar, M and Sameshima, K and Teixeira, MJ and Nicolelis,
MAL},
Title = {Functional convergence of parallel circuits within
subthalamic nucleus: Intra-operative multichannel-microelectrode
recording study during emotional, cognitive and motor
tasks},
Journal = {Movement Disorders : Official Journal of the Movement
Disorder Society},
Volume = {27},
Pages = {S205-S205},
Publisher = {WILEY-BLACKWELL},
Year = {2012},
Month = {June},
Key = {fds364108}
}
@article{fds364109,
Author = {Simon, SA and Oliveira-Maia, AJ and Roberts, CD and Walker, QD and Luo,
B and Kuhn, C and Nicolelis, MAL},
Title = {Gut-brain interactions and dopamine release},
Journal = {Chemical Senses},
Volume = {36},
Number = {1},
Pages = {E2-E3},
Publisher = {OXFORD UNIV PRESS},
Year = {2011},
Month = {January},
Key = {fds364109}
}
@article{fds364111,
Author = {Oliveira-Maia, AJ and Phan, T-HT and Mummalaneni, S and Melone, P and Nicolelis, MAL and Simon, SA and DeSimone, JA and Lyall,
V},
Title = {Effect of Nicotinic Acetylcholine Receptor (nAChR) Blockers,
Mecamylamine (Mec) and Dihydro-b-erthroidine (DH beta E) on
the Chorda Tympani Responses to Nicotine in TRPM5 Knockout
(KO) Mice},
Journal = {Chemical Senses},
Volume = {34},
Number = {7},
Pages = {A79-A79},
Publisher = {OXFORD UNIV PRESS},
Year = {2009},
Month = {September},
Key = {fds364111}
}
@article{fds275270,
Author = {Simon, SA and de Araujo, IE and Stapleton, JR and Nicolelis,
MAL},
Title = {Multisensory Processing of Gustatory Stimuli.},
Journal = {Chemosensory Perception},
Volume = {1},
Number = {2},
Pages = {95-102},
Year = {2008},
Month = {June},
ISSN = {1936-5802},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000261843000003&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {Gustatory perception is inherently multimodal, since
approximately the same time that intra-oral stimuli activate
taste receptors, somatosensory information is concurrently
sent to the CNS. We review evidence that gustatory
perception is intrinsically linked to concurrent
somatosensory processing. We will show that processing of
multisensory information can occur at the level of the taste
cells through to the gustatory cortex. We will also focus on
the fact that the same chemical and physical stimuli that
activate the taste system also activate the somatosensory
system (SS), but they may provide different types of
information to guide behavior.},
Doi = {10.1007/s12078-008-9014-4},
Key = {fds275270}
}
@article{fds364113,
Author = {Clayton, DA and Hanson, T and Nicolelis, MAL and Turner,
DA},
Title = {Subcortical Ensemble Recordings for the Control of a
Brain-Machine Interface},
Journal = {Neurosurgery},
Volume = {61},
Number = {1},
Pages = {212-212},
Publisher = {Ovid Technologies (Wolters Kluwer Health)},
Year = {2007},
Month = {July},
url = {http://dx.doi.org/10.1227/01.neu.0000279933.95869.eb},
Doi = {10.1227/01.neu.0000279933.95869.eb},
Key = {fds364113}
}
@article{fds364114,
Author = {Oliveira-Maia, AJ and de Araujo, IE and Riofrio, A and Nicolelis,
MAL and Simon, SA},
Title = {Cortical responses to the post-ingestive effects of sucrose
in TRPM5-/- mice},
Journal = {International Journal of Obesity (2005)},
Volume = {31},
Pages = {S102-S102},
Publisher = {NATURE PUBLISHING GROUP},
Year = {2007},
Month = {May},
Key = {fds364114}
}
@article{fds323342,
Author = {Yun, K and Lebedev, M and Nicolelis, MAL},
Title = {Prediction of motor timing using nonlinear analysis of local
field potentials},
Journal = {Ifmbe Proceedings},
Volume = {14},
Number = {1},
Pages = {1005-1008},
Year = {2007},
Month = {January},
ISBN = {9783540368397},
url = {http://dx.doi.org/10.1007/978-3-540-36841-0_239},
Abstract = {Recently we have shown that temporal intervals preceding
movement onset in a self-timed motor task can be accurately
predicted from the ensembles activity of cortical neurons
recorded in motor and premotor cortex. The aim of this study
was to predict behavioral time from local field potentials
(LFPs) recorded by the same electrodes. LFPs reflect mainly
postsynaptic potentials. Since LFPs integrate activity of
many neurons surrounding the electrode, they can contain
information about motor preparation and execution, and the
temporal intervals involved in the motor task. In
particular, LFP oscillations that are modulated during
movements have been reported in monkey motor cortex. In our
experiment, the monkeys performed self paced movements of
their hands. They had to withhold movements for at least
2.5s to receive a reward. This task was accompanied by
modulations of the LFP frequency in the 10-20 Hz range.
Nonlinear analysis methods – approximate entropy (ApEn),
correlation dimension (CD), and largest Lyapunov exponent
(LLE) – were used for quantify complexity (ApEn),
dimensional dynamics (CD), and chaotic dynamics (LLE) in the
LFP activity. ApEn and CD were modulated during movements.
ApEn and CD were higher in task periods preceding movement
onset. LLE also showed significant modulations: it was lower
during the delay period of the task. Thus, nonlinear
features of LFPs are correlated with motor timing. We
suggest using nonlinear analyses of LFPs as a supplement of
algorithms based on neuronal data in the design of
brain-machine interfaces.},
Doi = {10.1007/978-3-540-36841-0_239},
Key = {fds323342}
}
@article{fds364115,
Author = {Simon, SA and de Araujo, I and Gutierrez, R and Nicolelis,
MAL},
Title = {Neural ensemble representation of taste and appetitive
states},
Journal = {Chemical Senses},
Volume = {31},
Number = {8},
Pages = {E26-E26},
Publisher = {OXFORD UNIV PRESS},
Year = {2006},
Month = {October},
Key = {fds364115}
}
@article{fds364116,
Author = {Zachsenhouse, M and Nemets, S and Yoffe, A and Ben-Haim, Y and Lebedev,
MA and Nicolelis, MAL},
Title = {An info-gap approach to linear regression},
Journal = {2015 Ieee International Conference on Acoustics, Speech, and
Signal Processing (Icassp)},
Pages = {3251-3254},
Publisher = {IEEE},
Year = {2006},
Month = {January},
ISBN = {978-1-4244-0468-1},
Key = {fds364116}
}
@article{fds364117,
Author = {Nicolelis, MAL},
Title = {Building the future of brain research: The international
neuroscience network project},
Journal = {Movement Disorders : Official Journal of the Movement
Disorder Society},
Volume = {21},
Pages = {S20-S20},
Publisher = {WILEY-LISS},
Year = {2006},
Month = {January},
Key = {fds364117}
}
@article{fds364118,
Author = {Patil, PG and Nicolelis, MAL and Turner, DA},
Title = {Brain-machine interface: Ensembles of human subcortical
neurons and signals for neuroprosthetic control},
Journal = {Journal of Neurosurgery},
Volume = {100},
Number = {4},
Pages = {796-796},
Publisher = {AMER ASSOC NEUROLOGICAL SURGEONS},
Year = {2004},
Month = {April},
Key = {fds364118}
}
@article{fds275244,
Author = {Morizio, J and Won, D and Obeid, I and Bossetti, C and Nicolelis, M and Wolf, P},
Title = {16-channel neural pre-conditioning device},
Journal = {International Ieee/Embs Conference on Neural Engineering,
Ner},
Volume = {2003-January},
Pages = {104-107},
Publisher = {IEEE},
Year = {2003},
Month = {January},
ISBN = {0780375793},
ISSN = {1948-3546},
url = {http://dx.doi.org/10.1109/CNE.2003.1196767},
Abstract = {We present the mixed-signal circuit design, layout,
implementation techniques, and test data for a 16-channel
neural pre-conditioning device that is used to amplify and
filter signals acquired from chronically implanted
electrodes in an animal's brain. Schematics and simulation
data for each of the subcircuit macros are presented which
include a high gain, continuous time first order bandpass
filter pre-amplifier, a cascaded bandpass switch capacitor
filter, a selectable gain output buffer, and a voltage
controlled oscillator based clock generation circuitry. This
device was implemented using AMI's, 0.5 μm, double poly,
triple level metal, 5 V, CMOS technology. The layout and
floorplan, specifications and test data for this device
conclude this paper.},
Doi = {10.1109/CNE.2003.1196767},
Key = {fds275244}
}
@article{7535443,
Author = {Sanchez, JC and Kim, SP and Erdogmus, D and Rao, YN and Principe, JC and Wessberg, J and Nicolelis, M},
Title = {Input-output mapping performance of linear and nonlinear
models for estimating hand trajectories from cortical
neuronal firing patterns},
Journal = {Neural Networks for Signal Processing Proceedings of the
Ieee Workshop},
Volume = {2002-January},
Pages = {139-148},
Publisher = {IEEE},
Address = {Martigny, Switzerland},
Year = {2002},
Month = {January},
ISBN = {0780376161},
url = {http://dx.doi.org/10.1109/NNSP.2002.1030025},
Keywords = {brain models;FIR filters;handicapped aids;medical signal
processing;patient treatment;position control;real-time
systems;recurrent neural nets;},
Abstract = {Linear and nonlinear (TDNN) models have been shown to
estimate hand position using populations of action
potentials collected in the pre-motor and motor cortical
areas of a primate's brain. One of the applications of this
discovery is to restore movement in patients suffering from
paralysis. For real-time implementation of this technology,
reliable and accurate signal processing models that produce
small error variance in the estimated positions are
required. In this paper, we compare the mapping performance
of the FIR filter, gamma filter and recurrent neural network
(RNN) in the peaks of reaching movements. Each approach has
strengths and weaknesses that are compared experimentally.
The RNN approach shows very accurate peak position
estimations with small error variance.},
Doi = {10.1109/NNSP.2002.1030025},
Key = {7535443}
}
@article{fds364120,
Author = {Fanselow, EE and Reid, AP and Nicolelis, MAL},
Title = {Trigeminal nerve stimulation as a method for reduction of
PTZ-induced seizure activity in rats},
Journal = {Epilepsia},
Volume = {40},
Pages = {136-136},
Publisher = {LIPPINCOTT WILLIAMS & WILKINS},
Year = {1999},
Month = {January},
Key = {fds364120}
}
@article{fds364121,
Author = {Nicolelis, MAL},
Title = {Beyond maps: The dynamic and distributed organization of the
rat somatosensory system},
Journal = {Somatosensory & Motor Research},
Volume = {14},
Number = {1},
Pages = {63-64},
Publisher = {CARFAX PUBL CO},
Year = {1997},
Month = {January},
Key = {fds364121}
}
@article{fds364122,
Author = {Chapin, JK and Nicolelis, MAL},
Title = {What do dynamic receptive field properties reveal about
computation in recurrent thalamocortical
circuits?},
Journal = {Computational Neuroscience: Trends in Research,
1997},
Pages = {281-286},
Publisher = {PLENUM PRESS DIV PLENUM PUBLISHING CORP},
Editor = {Bower, JM},
Year = {1997},
Month = {January},
ISBN = {0-306-45699-0},
Key = {fds364122}
}
@article{fds364123,
Author = {Chapin, JK and Nicolelis, MAL},
Title = {Beyond single unit recording: Characterizing neural
information in networks of simultaneously recorded
neurons},
Journal = {Scale in Conscious Experience: Is the Brain Too Important to
Be Left to Specialists to Study?},
Pages = {133-&},
Publisher = {LAWRENCE ERLBAUM ASSOC PUBL},
Editor = {King, J and Pribram, KH},
Year = {1995},
Month = {January},
ISBN = {0-8058-2178-3},
Key = {fds364123}
}
%% Papers Published
@article{fds368087,
Author = {Wei, P-H and Nicolelis, MA and Zhao, G-G},
Title = {Rethinking the neurosurgical approach to brain disorders
from the network neuroscience perspective.},
Journal = {Science Bulletin},
Volume = {67},
Number = {23},
Pages = {2376-2380},
Year = {2022},
Month = {December},
url = {http://dx.doi.org/10.1016/j.scib.2022.11.012},
Doi = {10.1016/j.scib.2022.11.012},
Key = {fds368087}
}
@article{fds368086,
Author = {Nicolelis, MAL and Alho, EJL and Donati, ARC and Yonamine, S and Aratanha, MA and Bao, G and Campos, DSF and Almeida, S and Fischer, D and Shokur, S},
Title = {Training with noninvasive brain-machine interface, tactile
feedback, and locomotion to enhance neurological recovery in
individuals with complete paraplegia: a randomized pilot
study.},
Journal = {Scientific Reports},
Volume = {12},
Number = {1},
Pages = {20545},
Year = {2022},
Month = {November},
url = {http://dx.doi.org/10.1038/s41598-022-24864-5},
Abstract = {In recent years, our group and others have reported multiple
cases of consistent neurological recovery in people with
spinal cord injury (SCI) following a protocol that
integrates locomotion training with brain machine interfaces
(BMI). The primary objective of this pilot study was to
compare the neurological outcomes (motor, tactile,
nociception, proprioception, and vibration) in both an
intensive assisted locomotion training (LOC) and a
neurorehabilitation protocol integrating assisted locomotion
with a noninvasive brain-machine interface (L + BMI),
virtual reality, and tactile feedback. We also investigated
whether individuals with chronic-complete SCI could learn to
perform leg motor imagery. We ran a parallel two-arm
randomized pilot study; the experiments took place in São
Paulo, Brazil. Eight adults sensorimotor-complete (AIS A)
(all male) with chronic (> 6 months) traumatic spinal SCI
participated in the protocol that was organized in two
blocks of 14 weeks of training and an 8-week follow-up. The
participants were allocated to either the LOC group
(n = 4) or L + BMI group (n = 4) using block
randomization (blinded outcome assessment). We show three
important results: (i) locomotion training alone can induce
some level of neurological recovery in sensorimotor-complete
SCI, and (ii) the recovery rate is enhanced when such
locomotion training is associated with BMI and tactile
feedback (∆Mean Lower Extremity Motor score improvement
for LOC = + 2.5, L + B = + 3.5;
∆Pinprick score: LOC = + 3.75,
L + B = + 4.75 and ∆Tactile score
LOC = + 4.75, L + B = + 9.5). (iii)
Furthermore, we report that the BMI classifier accuracy was
significantly above the chance level for all participants in
L + B group. Our study shows potential for sensory and
motor improvement in individuals with chronic complete SCI
following a protocol with BMIs and locomotion therapy. We
report no dropouts nor adverse events in both subgroups
participating in the study, opening the possibility for a
more definitive clinical trial with a larger cohort of
people with SCI.Trial registration: http://www.ensaiosclinicos.gov.br/
identifier RBR-2pb8gq.},
Doi = {10.1038/s41598-022-24864-5},
Key = {fds368086}
}
@article{fds365336,
Author = {Nicolelis, MAL},
Title = {Brain-machine-brain interfaces as the foundation for the
next generation of neuroprostheses.},
Journal = {Natl Sci Rev},
Volume = {9},
Number = {10},
Pages = {nwab206},
Publisher = {Oxford University Press (OUP)},
Year = {2022},
Month = {October},
url = {http://dx.doi.org/10.1093/nsr/nwab206},
Doi = {10.1093/nsr/nwab206},
Key = {fds365336}
}
@article{fds359488,
Author = {Wen, S and Yin, A and Tseng, P-H and Itti, L and Lebedev, MA and Nicolelis,
M},
Title = {Capturing spike train temporal pattern with wavelet average
coefficient for brain machine interface.},
Journal = {Scientific Reports},
Volume = {11},
Number = {1},
Pages = {19020},
Year = {2021},
Month = {September},
url = {http://dx.doi.org/10.1038/s41598-021-98578-5},
Abstract = {Motor brain machine interfaces (BMIs) directly link the
brain to artificial actuators and have the potential to
mitigate severe body paralysis caused by neurological injury
or disease. Most BMI systems involve a decoder that analyzes
neural spike counts to infer movement intent. However, many
classical BMI decoders (1) fail to take advantage of
temporal patterns of spike trains, possibly over long time
horizons; (2) are insufficient to achieve good BMI
performance at high temporal resolution, as the underlying
Gaussian assumption of decoders based on spike counts is
violated. Here, we propose a new statistical feature that
represents temporal patterns or temporal codes of spike
events with richer description-wavelet average coefficients
(WAC)-to be used as decoder input instead of spike counts.
We constructed a wavelet decoder framework by using WAC
features with a sliding-window approach, and compared the
resulting decoder against classical decoders (Wiener and
Kalman family) and new deep learning based decoders ( Long
Short-Term Memory) using spike count features. We found that
the sliding-window approach boosts decoding temporal
resolution, and using WAC features significantly improves
decoding performance over using spike count
features.},
Doi = {10.1038/s41598-021-98578-5},
Key = {fds359488}
}
@article{fds357341,
Author = {Nicolelis, MAL and Raimundo, RLG and Peixoto, PS and Andreazzi,
CS},
Title = {The impact of super-spreader cities, highways, and intensive
care availability in the early stages of the COVID-19
epidemic in Brazil.},
Journal = {Scientific Reports},
Volume = {11},
Number = {1},
Pages = {13001},
Year = {2021},
Month = {June},
url = {http://dx.doi.org/10.1038/s41598-021-92263-3},
Abstract = {Although international airports served as main entry points
for SARS-CoV-2, the factors driving the uneven geographic
spread of COVID-19 cases and deaths in Brazil remain mostly
unknown. Here we show that three major factors influenced
the early macro-geographical dynamics of COVID-19 in Brazil.
Mathematical modeling revealed that the "super-spreading
city" of São Paulo initially accounted for more than 85% of
the case spread in the entire country. By adding only 16
other spreading cities, we accounted for 98-99% of the cases
reported during the first 3 months of the pandemic in
Brazil. Moreover, 26 federal highways accounted for about
30% of SARS-CoV-2's case spread. As cases increased in the
Brazilian interior, the distribution of COVID-19 deaths
began to correlate with the allocation of the country's
intensive care units (ICUs), which is heavily weighted
towards state capitals. Thus, severely ill patients living
in the countryside had to be transported to state capitals
to access ICU beds, creating a "boomerang effect" that
contributed to skew the distribution of COVID-19 deaths.
Therefore, if (i) a lockdown had been imposed earlier on in
spreader-capitals, (ii) mandatory road traffic restrictions
had been enforced, and (iii) a more equitable geographic
distribution of ICU beds existed, the impact of COVID-19 in
Brazil would be significantly lower.},
Doi = {10.1038/s41598-021-92263-3},
Key = {fds357341}
}
@article{fds357025,
Author = {Yadav, AP and Li, S and Krucoff, MO and Lebedev, MA and Abd-El-Barr, MM and Nicolelis, MAL},
Title = {Generating artificial sensations with spinal cord
stimulation in primates and rodents.},
Journal = {Brain Stimul},
Volume = {14},
Number = {4},
Pages = {825-836},
Year = {2021},
url = {http://dx.doi.org/10.1016/j.brs.2021.04.024},
Abstract = {For patients who have lost sensory function due to a
neurological injury such as spinal cord injury (SCI),
stroke, or amputation, spinal cord stimulation (SCS) may
provide a mechanism for restoring somatic sensations via an
intuitive, non-visual pathway. Inspired by this vision, here
we trained rhesus monkeys and rats to detect and
discriminate patterns of epidural SCS. Thereafter, we
constructed psychometric curves describing the relationship
between different SCS parameters and the animal's ability to
detect SCS and/or changes in its characteristics. We found
that the stimulus detection threshold decreased with higher
frequency, longer pulse-width, and increasing duration of
SCS. Moreover, we found that monkeys were able to
discriminate temporally- and spatially-varying patterns
(i.e. variations in frequency and location) of SCS delivered
through multiple electrodes. Additionally, sensory
discrimination of SCS-induced sensations in rats obeyed
Weber's law of just-noticeable differences. These findings
suggest that by varying SCS intensity, temporal pattern, and
location different sensory experiences can be evoked. As
such, we posit that SCS can provide intuitive sensory
feedback in neuroprosthetic devices.},
Doi = {10.1016/j.brs.2021.04.024},
Key = {fds357025}
}
@article{fds354284,
Author = {Cheng, G and Ehrlich, SK and Lebedev, M and Nicolelis,
MAL},
Title = {Neuroengineering challenges of fusing robotics and
neuroscience.},
Journal = {Sci Robot},
Volume = {5},
Number = {49},
Year = {2020},
Month = {December},
url = {http://dx.doi.org/10.1126/scirobotics.abd1911},
Abstract = {Advances in neuroscience are inspiring developments in
robotics and vice versa.},
Doi = {10.1126/scirobotics.abd1911},
Key = {fds354284}
}
@article{fds348440,
Author = {Yadav, AP and Li, D and Nicolelis, MAL},
Title = {A Brain to Spine Interface for Transferring Artificial
Sensory Information.},
Journal = {Scientific Reports},
Volume = {10},
Number = {1},
Pages = {900},
Year = {2020},
Month = {January},
url = {http://dx.doi.org/10.1038/s41598-020-57617-3},
Abstract = {Lack of sensory feedback is a major obstacle in the rapid
absorption of prosthetic devices by the brain. While
electrical stimulation of cortical and subcortical
structures provides unique means to deliver sensory
information to higher brain structures, these approaches
require highly invasive surgery and are dependent on
accurate targeting of brain structures. Here, we propose a
semi-invasive method, Dorsal Column Stimulation (DCS) as a
tool for transferring sensory information to the brain.
Using this new approach, we show that rats can learn to
discriminate artificial sensations generated by DCS and that
DCS-induced learning results in corticostriatal plasticity.
We also demonstrate a proof of concept brain-to-spine
interface (BTSI), whereby tactile and artificial sensory
information are decoded from the brain of an "encoder" rat,
transformed into DCS pulses, and delivered to the spinal
cord of a second "decoder" rat while the latter performs an
analog-to-digital conversion during a sensory discrimination
task. These results suggest that DCS can be used as an
effective sensory channel to transmit prosthetic information
to the brain or between brains, and could be developed as a
novel platform for delivering tactile and proprioceptive
feedback in clinical applications of brain-machine
interfaces.},
Doi = {10.1038/s41598-020-57617-3},
Key = {fds348440}
}
@article{fds347361,
Author = {Lebedev, MA and Ossadtchi, A and Mill, NA and Urpí, NA and Cervera, MR and Nicolelis, MAL},
Title = {Analysis of neuronal ensemble activity reveals the pitfalls
and shortcomings of rotation dynamics.},
Journal = {Scientific Reports},
Volume = {9},
Number = {1},
Pages = {18978},
Year = {2019},
Month = {December},
url = {http://dx.doi.org/10.1038/s41598-019-54760-4},
Abstract = {Back in 2012, Churchland and his colleagues proposed that
"rotational dynamics", uncovered through linear
transformations of multidimensional neuronal data, represent
a fundamental type of neuronal population processing in a
variety of organisms, from the isolated leech central
nervous system to the primate motor cortex. Here, we
evaluated this claim using Churchland's own data and simple
simulations of neuronal responses. We observed that
rotational patterns occurred in neuronal populations when
(1) there was a temporal sequence in peak firing rates
exhibited by individual neurons, and (2) this sequence
remained consistent across different experimental
conditions. Provided that such a temporal order of peak
firing rates existed, rotational patterns could be easily
obtained using a rather arbitrary computer simulation of
neural activity; modeling of any realistic properties of
motor cortical responses was not needed. Additionally,
arbitrary traces, such as Lissajous curves, could be easily
obtained from Churchland's data with multiple linear
regression. While these observations suggest that temporal
sequences of neuronal responses could be visualized as
rotations with various methods, we express doubt about
Churchland et al.'s bold assessment that such rotations are
related to "an unexpected yet surprisingly simple structure
in the population response", which "explains many of the
confusing features of individual neural responses". Instead,
we argue that their approach provides little, if any,
insight on the underlying neuronal mechanisms employed by
neuronal ensembles to encode motor behaviors in any
species.},
Doi = {10.1038/s41598-019-54760-4},
Key = {fds347361}
}
@article{fds347362,
Author = {Selfslagh, A and Shokur, S and Campos, DSF and Donati, ARC and Almeida,
S and Yamauti, SY and Coelho, DB and Bouri, M and Nicolelis,
MAL},
Title = {Author Correction: Non-invasive, Brain-controlled Functional
Electrical Stimulation for Locomotion Rehabilitation in
Individuals with Paraplegia.},
Journal = {Scientific Reports},
Volume = {9},
Number = {1},
Pages = {18654},
Year = {2019},
Month = {December},
url = {http://dx.doi.org/10.1038/s41598-019-54834-3},
Abstract = {An amendment to this paper has been published and can be
accessed via a link at the top of the paper.},
Doi = {10.1038/s41598-019-54834-3},
Key = {fds347362}
}
@article{fds346629,
Author = {O'Doherty, JE and Shokur, S and Medina, LE and Lebedev, MA and Nicolelis, MAL},
Title = {Creating a neuroprosthesis for active tactile exploration of
textures.},
Journal = {Proc Natl Acad Sci U S A},
Volume = {116},
Number = {43},
Pages = {21821-21827},
Year = {2019},
Month = {October},
url = {http://dx.doi.org/10.1073/pnas.1908008116},
Abstract = {Intracortical microstimulation (ICMS) of the primary
somatosensory cortex (S1) can produce percepts that mimic
somatic sensation and, thus, has potential as an approach to
sensorize prosthetic limbs. However, it is not known whether
ICMS could recreate active texture exploration-the ability
to infer information about object texture by using one's
fingertips to scan a surface. Here, we show that ICMS of S1
can convey information about the spatial frequencies of
invisible virtual gratings through a process of active
tactile exploration. Two rhesus monkeys scanned pairs of
visually identical screen objects with the fingertip of a
hand avatar-controlled first via a joystick and later via a
brain-machine interface-to find the object with denser
virtual gratings. The gratings consisted of evenly spaced
ridges that were signaled through individual ICMS pulses
generated whenever the avatar's fingertip crossed a ridge.
The monkeys learned to interpret these ICMS patterns, evoked
by the interplay of their voluntary movements and the
virtual textures of each object, to perform a sensory
discrimination task. Discrimination accuracy followed
Weber's law of just-noticeable differences (JND) across a
range of grating densities; a finding that matches normal
cutaneous sensation. Moreover, 1 monkey developed an active
scanning strategy where avatar velocity was integrated with
the ICMS pulses to interpret the texture information. We
propose that this approach could equip upper-limb
neuroprostheses with direct access to texture features
acquired during active exploration of natural
objects.},
Doi = {10.1073/pnas.1908008116},
Key = {fds346629}
}
@article{fds364105,
Author = {Yadav, A and Li, D and Nicolelis, M},
Title = {A Brain to Spine Interface for Transferring Artificial
Sensory Information},
Year = {2019},
Month = {October},
url = {http://dx.doi.org/10.1101/807735},
Abstract = {Abstract Lack of sensory feedback is a major obstacle in the
rapid absorption of prosthetic devices by the brain. While
electrical stimulation of cortical and subcortical
structures provides unique means to deliver sensory
information to higher brain structures, these approaches
require highly invasive surgery and are dependent on
accurate targeting of brain structures. Here, we propose a
semi-invasive method, Dorsal Column Stimulation (DCS) as a
tool for transferring sensory information to the brain.
Using this new approach, we show that rats can learn to
discriminate artificial sensations generated by DCS and that
DCS-induced learning results in corticostriatal plasticity.
We also demonstrate a proof of concept brain-to-spine
interface (BTSI), whereby tactile and artificial sensory
information are decoded from the brain of an “encoder”
rat, transformed into DCS pulses, and delivered to the
spinal cord of a second “decoder” rat while the latter
performs an analog-to-digital conversion during a tactile
discrimination task. These results suggest that DCS can be
used as an effective sensory channel to transmit prosthetic
information to the brain or between brains, and could be
developed as a novel platform for delivering tactile and
proprioceptive feedback in clinical applications of
brain-machine interfaces.},
Doi = {10.1101/807735},
Key = {fds364105}
}
@article{fds343621,
Author = {Tseng, P-H and Urpi, NA and Lebedev, M and Nicolelis,
M},
Title = {Decoding Movements from Cortical Ensemble Activity Using a
Long Short-Term Memory Recurrent Network.},
Journal = {Neural Comput},
Volume = {31},
Number = {6},
Pages = {1085-1113},
Year = {2019},
Month = {June},
url = {http://dx.doi.org/10.1162/neco_a_01189},
Abstract = {Although many real-time neural decoding algorithms have been
proposed for brain-machine interface (BMI) applications over
the years, an optimal, consensual approach remains elusive.
Recent advances in deep learning algorithms provide new
opportunities for improving the design of BMI decoders,
including the use of recurrent artificial neural networks to
decode neuronal ensemble activity in real time. Here, we
developed a long-short term memory (LSTM) decoder for
extracting movement kinematics from the activity of large (N
= 134-402) populations of neurons, sampled simultaneously
from multiple cortical areas, in rhesus monkeys performing
motor tasks. Recorded regions included primary motor, dorsal
premotor, supplementary motor, and primary somatosensory
cortical areas. The LSTM's capacity to retain information
for extended periods of time enabled accurate decoding for
tasks that required both movements and periods of
immobility. Our LSTM algorithm significantly outperformed
the state-of-the-art unscented Kalman filter when applied to
three tasks: center-out arm reaching, bimanual reaching, and
bipedal walking on a treadmill. Notably, LSTM units
exhibited a variety of well-known physiological features of
cortical neuronal activity, such as directional tuning and
neuronal dynamics across task epochs. LSTM modeled several
key physiological attributes of cortical circuits involved
in motor tasks. These findings suggest that LSTM-based
approaches could yield a better algorithm strategy for
neuroprostheses that employ BMIs to restore movement in
severely disabled patients.},
Doi = {10.1162/neco_a_01189},
Key = {fds343621}
}
@article{fds342791,
Author = {Selfslagh, A and Shokur, S and Campos, DSF and Donati, ARC and Almeida,
S and Yamauti, SY and Coelho, DB and Bouri, M and Nicolelis,
MAL},
Title = {Non-invasive, Brain-controlled Functional Electrical
Stimulation for Locomotion Rehabilitation in Individuals
with Paraplegia.},
Journal = {Scientific Reports},
Volume = {9},
Number = {1},
Pages = {6782},
Year = {2019},
Month = {May},
url = {http://dx.doi.org/10.1038/s41598-019-43041-9},
Abstract = {Spinal cord injury (SCI) impairs the flow of sensory and
motor signals between the brain and the areas of the body
located below the lesion level. Here, we describe a
neurorehabilitation setup combining several approaches that
were shown to have a positive effect in patients with SCI:
gait training by means of non-invasive, surface functional
electrical stimulation (sFES) of the lower-limbs,
proprioceptive and tactile feedback, balance control through
overground walking and cue-based decoding of cortical motor
commands using a brain-machine interface (BMI). The central
component of this new approach was the development of a
novel muscle stimulation paradigm for step generation using
16 sFES channels taking all sub-phases of physiological gait
into account. We also developed a new BMI protocol to
identify left and right leg motor imagery that was used to
trigger an sFES-generated step movement. Our system was
tested and validated with two patients with chronic
paraplegia. These patients were able to walk safely with
65-70% body weight support, accumulating a total of 4,580
steps with this setup. We observed cardiovascular
improvements and less dependency on walking assistance, but
also partial neurological recovery in both patients, with
substantial rates of motor improvement for one of
them.},
Doi = {10.1038/s41598-019-43041-9},
Key = {fds342791}
}
@article{fds364106,
Author = {Kunicki, C and C Moioli and R and Pais-Vieira, M and Salles Cunha Peres,
A and Morya, E and A L Nicolelis and M},
Title = {Frequency-specific coupling in fronto-parieto-occipital
cortical circuits underlie active tactile
discrimination.},
Journal = {Scientific Reports},
Volume = {9},
Number = {1},
Pages = {5105},
Year = {2019},
Month = {March},
url = {http://dx.doi.org/10.1038/s41598-019-41516-3},
Abstract = {Processing of tactile sensory information in rodents is
critically dependent on the communication between the
primary somatosensory cortex (S1) and higher-order
integrative cortical areas. Here, we have simultaneously
characterized single-unit activity and local field potential
(LFP) dynamics in the S1, primary visual cortex (V1),
anterior cingulate cortex (ACC), posterior parietal cortex
(PPC), while freely moving rats performed an active tactile
discrimination task. Simultaneous single unit recordings
from all these cortical regions revealed statistically
significant neuronal firing rate modulations during all task
phases (anticipatory, discrimination, response, and reward).
Meanwhile, phase analysis of pairwise LFP recordings
revealed the occurrence of long-range synchronization across
the sampled fronto-parieto-occipital cortical areas during
tactile sampling. Causal analysis of the same pairwise
recorded LFPs demonstrated the occurrence of complex dynamic
interactions between cortical areas throughout the
fronto-parietal-occipital loop. These interactions changed
significantly between cortical regions as a function of
frequencies (i.e. beta, theta and gamma) and according to
the different phases of the behavioral task. Overall, these
findings indicate that active tactile discrimination by rats
is characterized by much more widespread and dynamic complex
interactions within the fronto-parieto-occipital cortex than
previously anticipated.},
Doi = {10.1038/s41598-019-41516-3},
Key = {fds364106}
}
@article{fds336090,
Author = {Yin, A and Tseng, PH and Rajangam, S and Lebedev, MA and Nicolelis,
MAL},
Title = {Place Cell-Like Activity in the Primary Sensorimotor and
Premotor Cortex During Monkey Whole-Body
Navigation.},
Journal = {Scientific Reports},
Volume = {8},
Number = {1},
Pages = {9184},
Year = {2018},
Month = {June},
url = {http://dx.doi.org/10.1038/s41598-018-27472-4},
Abstract = {Primary motor (M1), primary somatosensory (S1) and dorsal
premotor (PMd) cortical areas of rhesus monkeys previously
have been associated only with sensorimotor control of limb
movements. Here we show that a significant number of neurons
in these areas also represent body position and orientation
in space. Two rhesus monkeys (K and M) used a wheelchair
controlled by a brain-machine interface (BMI) to navigate in
a room. During this whole-body navigation, the discharge
rates of M1, S1, and PMd neurons correlated with the
two-dimensional (2D) room position and the direction of the
wheelchair and the monkey head. This place cell-like
activity was observed in both monkeys, with 44.6% and 33.3%
of neurons encoding room position in monkeys K and M,
respectively, and the overlapping populations of 41.0% and
16.0% neurons encoding head direction. These observations
suggest that primary sensorimotor and premotor cortical
areas in primates are likely involved in allocentrically
representing body position in space during whole-body
navigation, which is an unexpected finding given the
classical hierarchical model of cortical processing that
attributes functional specialization for spatial processing
to the hippocampal formation.},
Doi = {10.1038/s41598-018-27472-4},
Key = {fds336090}
}
@article{fds333768,
Author = {Tseng, P-H and Rajangam, S and Lehew, G and Lebedev, MA and Nicolelis,
MAL},
Title = {Interbrain cortical synchronization encodes multiple aspects
of social interactions in monkey pairs.},
Journal = {Scientific Reports},
Volume = {8},
Number = {1},
Pages = {4699},
Year = {2018},
Month = {March},
url = {http://dx.doi.org/10.1038/s41598-018-22679-x},
Abstract = {While it is well known that the primate brain evolved to
cope with complex social contingencies, the
neurophysiological manifestation of social interactions in
primates is not well understood. Here, concurrent wireless
neuronal ensemble recordings from pairs of monkeys were
conducted to measure interbrain cortical synchronization
(ICS) during a whole-body navigation task that involved
continuous social interaction of two monkeys. One monkey,
the passenger, was carried in a robotic wheelchair to a food
dispenser, while a second monkey, the observer, remained
stationary, watching the passenger. The two monkeys
alternated the passenger and the observer roles. Concurrent
neuronal ensemble recordings from the monkeys' motor cortex
and the premotor dorsal area revealed episodic occurrence of
ICS with probability that depended on the wheelchair
kinematics, the passenger-observer distance, and the
passenger-food distance - the social-interaction factors
previously described in behavioral studies. These results
suggest that ICS represents specific aspects of primate
social interactions.},
Doi = {10.1038/s41598-018-22679-x},
Key = {fds333768}
}
@article{fds340155,
Author = {Shokur, S and Donati, ARC and Campos, DSF and Gitti, C and Bao, G and Fischer, D and Almeida, S and Braga, VAS and Augusto, P and Petty, C and Alho, EJL and Lebedev, M and Song, AW and Nicolelis,
MAL},
Title = {Training with brain-machine interfaces, visuo-tactile
feedback and assisted locomotion improves sensorimotor,
visceral, and psychological signs in chronic paraplegic
patients.},
Journal = {Plos One},
Volume = {13},
Number = {11},
Pages = {e0206464},
Year = {2018},
url = {http://dx.doi.org/10.1371/journal.pone.0206464},
Abstract = {Spinal cord injury (SCI) induces severe deficiencies in
sensory-motor and autonomic functions and has a significant
negative impact on patients' quality of life. There is
currently no systematic rehabilitation technique assuring
recovery of the neurological impairments caused by a
complete SCI. Here, we report significant clinical
improvement in a group of seven chronic SCI patients (six
AIS A, one AIS B) following a 28-month, multi-step protocol
that combined training with non-invasive brain-machine
interfaces, visuo-tactile feedback and assisted locomotion.
All patients recovered significant levels of nociceptive
sensation below their original SCI (up to 16 dermatomes,
average 11 dermatomes), voluntary motor functions
(lower-limbs muscle contractions plus multi-joint movements)
and partial sensory function for several modalities
(proprioception, tactile, pressure, vibration). Patients
also recovered partial intestinal, urinary and sexual
functions. By the end of the protocol, all patients had
their AIS classification upgraded (six from AIS A to C, one
from B to C). These improvements translated into significant
changes in the patients' quality of life as measured by
standardized psychological instruments. Reexamination of one
patient that discontinued the protocol after 12 months of
training showed that the 16-month break resulted in
neurological stagnation and no reclassification. We suggest
that our neurorehabilitation protocol, based uniquely on
non-invasive technology (therefore necessitating no surgical
operation), can become a promising therapy for patients
diagnosed with severe paraplegia (AIS A, B), even at the
chronic phase of their lesion.},
Doi = {10.1371/journal.pone.0206464},
Key = {fds340155}
}
@article{fds326639,
Author = {Ramakrishnan, A and Byun, YW and Rand, K and Pedersen, CE and Lebedev,
MA and Nicolelis, MAL},
Title = {Cortical neurons multiplex reward-related signals along with
sensory and motor information.},
Journal = {Proc Natl Acad Sci U S A},
Volume = {114},
Number = {24},
Pages = {E4841-E4850},
Year = {2017},
Month = {June},
url = {http://dx.doi.org/10.1073/pnas.1703668114},
Abstract = {Rewards are known to influence neural activity associated
with both motor preparation and execution. This influence
can be exerted directly upon the primary motor (M1) and
somatosensory (S1) cortical areas via the projections from
reward-sensitive dopaminergic neurons of the midbrain
ventral tegmental areas. However, the neurophysiological
manifestation of reward-related signals in M1 and S1 are not
well understood. Particularly, it is unclear how the neurons
in these cortical areas multiplex their traditional
functions related to the control of spatial and temporal
characteristics of movements with the representation of
rewards. To clarify this issue, we trained rhesus monkeys to
perform a center-out task in which arm movement direction,
reward timing, and magnitude were manipulated independently.
Activity of several hundred cortical neurons was
simultaneously recorded using chronically implanted
microelectrode arrays. Many neurons (9-27%) in both M1 and
S1 exhibited activity related to reward anticipation.
Additionally, neurons in these areas responded to a mismatch
between the reward amount given to the monkeys and the
amount they expected: A lower-than-expected reward caused a
transient increase in firing rate in 60-80% of the total
neuronal sample, whereas a larger-than-expected reward
resulted in a decreased firing rate in 20-35% of the
neurons. Moreover, responses of M1 and S1 neurons to reward
omission depended on the direction of movements that led to
those rewards. These observations suggest that sensorimotor
cortical neurons corepresent rewards and movement-related
activity, presumably to enable reward-based
learning.},
Doi = {10.1073/pnas.1703668114},
Key = {fds326639}
}
@article{fds326638,
Author = {Yadav, AP and Nicolelis, MAL},
Title = {Electrical stimulation of the dorsal columns of the spinal
cord for Parkinson's disease.},
Journal = {Mov Disord},
Volume = {32},
Number = {6},
Pages = {820-832},
Year = {2017},
Month = {June},
url = {http://dx.doi.org/10.1002/mds.27033},
Abstract = {Spinal cord stimulation has been used for the treatment of
chronic pain for decades. In 2009, our laboratory proposed,
based on studies in rodents, that electrical stimulation of
the dorsal columns of the spinal cord could become an
effective treatment for motor symptoms associated with
Parkinson's disease (PD). Since our initial report in
rodents and a more recent study in primates, several
clinical studies have now described beneficial effects of
dorsal column stimulation in parkinsonian patients. In
primates, we have shown that dorsal column stimulation
activates multiple structures along the somatosensory
pathway and desynchronizes the pathological cortico-striatal
oscillations responsible for the manifestation of PD
symptoms. Based on recent evidence, we argue that
neurological disorders such as PD can be broadly classified
as diseases emerging from abnormal neuronal timing, leading
to pathological brain states, and that the spinal cord could
be used as a "channel" to transmit therapeutic electrical
signals to disrupt these abnormalities. © 2017
International Parkinson and Movement Disorder
Society.},
Doi = {10.1002/mds.27033},
Key = {fds326638}
}
@article{fds325514,
Author = {Lebedev, MA and Nicolelis, MAL},
Title = {Brain-Machine Interfaces: From Basic Science to
Neuroprostheses and Neurorehabilitation.},
Journal = {Physiol Rev},
Volume = {97},
Number = {2},
Pages = {767-837},
Year = {2017},
Month = {April},
url = {http://dx.doi.org/10.1152/physrev.00027.2016},
Abstract = {Brain-machine interfaces (BMIs) combine methods, approaches,
and concepts derived from neurophysiology, computer science,
and engineering in an effort to establish real-time
bidirectional links between living brains and artificial
actuators. Although theoretical propositions and some proof
of concept experiments on directly linking the brains with
machines date back to the early 1960s, BMI research only
took off in earnest at the end of the 1990s, when this
approach became intimately linked to new neurophysiological
methods for sampling large-scale brain activity. The classic
goals of BMIs are 1) to unveil and utilize principles of
operation and plastic properties of the distributed and
dynamic circuits of the brain and 2) to create new therapies
to restore mobility and sensations to severely disabled
patients. Over the past decade, a wide range of BMI
applications have emerged, which considerably expanded these
original goals. BMI studies have shown neural control over
the movements of robotic and virtual actuators that enact
both upper and lower limb functions. Furthermore, BMIs have
also incorporated ways to deliver sensory feedback,
generated from external actuators, back to the brain. BMI
research has been at the forefront of many
neurophysiological discoveries, including the demonstration
that, through continuous use, artificial tools can be
assimilated by the primate brain's body schema. Work on BMIs
has also led to the introduction of novel
neurorehabilitation strategies. As a result of these
efforts, long-term continuous BMI use has been recently
implicated with the induction of partial neurological
recovery in spinal cord injury patients.},
Doi = {10.1152/physrev.00027.2016},
Key = {fds325514}
}
@article{fds325874,
Author = {Vouga, T and Zhuang, KZ and Olivier, J and Lebedev, MA and Nicolelis,
MAL and Bouri, M and Bleuler, H},
Title = {EXiO-A Brain-Controlled Lower Limb Exoskeleton for Rhesus
Macaques.},
Journal = {Ieee Trans Neural Syst Rehabil Eng},
Volume = {25},
Number = {2},
Pages = {131-141},
Year = {2017},
Month = {February},
url = {http://dx.doi.org/10.1109/TNSRE.2017.2659654},
Abstract = {Recent advances in the field of brain-machine interfaces
(BMIs) have demonstrated enormous potential to shape the
future of rehabilitation and prosthetic devices. Here, a
lower-limb exoskeleton controlled by the intracortical
activity of an awake behaving rhesus macaque is presented as
a proof-of-concept for a locomotorBMI. A detailed
description of the mechanical device, including its
innovative features and first experimental results, is
provided. During operation, BMI-decoded position and
velocity are directly mapped onto the bipedal exoskeleton's
motions, which then move the monkey's legs as the monkey
remains physicallypassive. To meet the unique requirements
of such an application, the exoskeleton's features include:
high output torque with backdrivable actuation, size
adjustability, and safe user-robot interface. In addition, a
novel rope transmission is introduced and implemented. To
test the performance of the exoskeleton, a mechanical
assessment was conducted, which yielded quantifiable results
for transparency, efficiency, stiffness, and tracking
performance. Usage under both brain control and automated
actuation demonstrates the device's capability to fulfill
the demanding needs of this application. These results lay
the groundwork for further advancement in BMI-controlled
devices for primates including humans.},
Doi = {10.1109/TNSRE.2017.2659654},
Key = {fds325874}
}
@article{fds330459,
Author = {Nicolelis, MAL},
Title = {Are we at risk of becoming biological digital
machines?},
Journal = {Nature Human Behaviour},
Volume = {1},
Number = {1},
Pages = {0008-0008},
Publisher = {Springer Nature},
Year = {2017},
Month = {January},
url = {http://dx.doi.org/10.1038/s41562-016-0008},
Doi = {10.1038/s41562-016-0008},
Key = {fds330459}
}
@article{fds331884,
Author = {Thomson, EE and Zea, I and Windham, W and Thenaisie, Y and Walker, C and Pedowitz, J and França, W and Graneiro, AL and Nicolelis,
MAL},
Title = {Cortical Neuroprosthesis Merges Visible and Invisible Light
Without Impairing Native Sensory Function.},
Journal = {Eneuro},
Volume = {4},
Number = {6},
Pages = {ENEURO.0262-ENEU17.2017},
Year = {2017},
url = {http://dx.doi.org/10.1523/ENEURO.0262-17.2017},
Abstract = {Adult rats equipped with a sensory prosthesis, which
transduced infrared (IR) signals into electrical signals
delivered to somatosensory cortex (S1), took approximately 4
d to learn a four-choice IR discrimination task. Here, we
show that when such IR signals are projected to the primary
visual cortex (V1), rats that are pretrained in a
visual-discrimination task typically learn the same IR
discrimination task on their first day of training. However,
without prior training on a visual discrimination task, the
learning rates for S1- and V1-implanted animals converged,
suggesting there is no intrinsic difference in learning rate
between the two areas. We also discovered that animals were
able to integrate IR information into the ongoing visual
processing stream in V1, performing a visual-IR integration
task in which they had to combine IR and visual information.
Furthermore, when the IR prosthesis was implanted in S1,
rats showed no impairment in their ability to use their
whiskers to perform a tactile discrimination task. Instead,
in some rats, this ability was actually enhanced.
Cumulatively, these findings suggest that cortical sensory
neuroprostheses can rapidly augment the representational
scope of primary sensory areas, integrating novel sources of
information into ongoing processing while incurring minimal
loss of native function.},
Doi = {10.1523/ENEURO.0262-17.2017},
Key = {fds331884}
}
@article{fds323341,
Author = {Shokur, S and Gallo, S and Moioli, RC and Donati, ARC and Morya, E and Bleuler, H and Nicolelis, MAL},
Title = {Assimilation of virtual legs and perception of floor texture
by complete paraplegic patients receiving artificial tactile
feedback.},
Journal = {Scientific Reports},
Volume = {6},
Pages = {32293},
Year = {2016},
Month = {September},
url = {http://dx.doi.org/10.1038/srep32293},
Abstract = {Spinal cord injuries disrupt bidirectional communication
between the patient's brain and body. Here, we demonstrate a
new approach for reproducing lower limb somatosensory
feedback in paraplegics by remapping missing leg/foot
tactile sensations onto the skin of patients' forearms. A
portable haptic display was tested in eight patients in a
setup where the lower limbs were simulated using immersive
virtual reality (VR). For six out of eight patients, the
haptic display induced the realistic illusion of walking on
three different types of floor surfaces: beach sand, a paved
street or grass. Additionally, patients experienced the
movements of the virtual legs during the swing phase or the
sensation of the foot rolling on the floor while walking.
Relying solely on this tactile feedback, patients reported
the position of the avatar leg during virtual walking.
Crossmodal interference between vision of the virtual legs
and tactile feedback revealed that patients assimilated the
virtual lower limbs as if they were their own legs. We
propose that the addition of tactile feedback to
neuroprosthetic devices is essential to restore a full lower
limb perceptual experience in spinal cord injury (SCI)
patients, and will ultimately, lead to a higher rate of
prosthetic acceptance/use and a better level of motor
proficiency.},
Doi = {10.1038/srep32293},
Key = {fds323341}
}
@article{fds323340,
Author = {Pais-Vieira, M and Yadav, AP and Moreira, D and Guggenmos, D and Santos,
A and Lebedev, M and Nicolelis, MAL},
Title = {A Closed Loop Brain-machine Interface for Epilepsy Control
Using Dorsal Column Electrical Stimulation.},
Journal = {Scientific Reports},
Volume = {6},
Pages = {32814},
Year = {2016},
Month = {September},
url = {http://dx.doi.org/10.1038/srep32814},
Abstract = {Although electrical neurostimulation has been proposed as an
alternative treatment for drug-resistant cases of epilepsy,
current procedures such as deep brain stimulation, vagus,
and trigeminal nerve stimulation are effective only in a
fraction of the patients. Here we demonstrate a closed loop
brain-machine interface that delivers electrical stimulation
to the dorsal column (DCS) of the spinal cord to suppress
epileptic seizures. Rats were implanted with cortical
recording microelectrodes and spinal cord stimulating
electrodes, and then injected with pentylenetetrazole to
induce seizures. Seizures were detected in real time from
cortical local field potentials, after which DCS was
applied. This method decreased seizure episode frequency by
44% and seizure duration by 38%. We argue that the
therapeutic effect of DCS is related to modulation of
cortical theta waves, and propose that this closed-loop
interface has the potential to become an effective and
semi-invasive treatment for refractory epilepsy and other
neurological disorders.},
Doi = {10.1038/srep32814},
Key = {fds323340}
}
@article{fds323339,
Author = {Donati, ARC and Shokur, S and Morya, E and Campos, DSF and Moioli, RC and Gitti, CM and Augusto, PB and Tripodi, S and Pires, CG and Pereira, GA and Brasil, FL and Gallo, S and Lin, AA and Takigami, AK and Aratanha, MA and Joshi, S and Bleuler, H and Cheng, G and Rudolph, A and Nicolelis,
MAL},
Title = {Long-Term Training with a Brain-Machine Interface-Based Gait
Protocol Induces Partial Neurological Recovery in Paraplegic
Patients.},
Journal = {Scientific Reports},
Volume = {6},
Pages = {30383},
Year = {2016},
Month = {August},
url = {http://dx.doi.org/10.1038/srep30383},
Abstract = {Brain-machine interfaces (BMIs) provide a new assistive
strategy aimed at restoring mobility in severely paralyzed
patients. Yet, no study in animals or in human subjects has
indicated that long-term BMI training could induce any type
of clinical recovery. Eight chronic (3-13 years) spinal cord
injury (SCI) paraplegics were subjected to long-term
training (12 months) with a multi-stage BMI-based gait
neurorehabilitation paradigm aimed at restoring locomotion.
This paradigm combined intense immersive virtual reality
training, enriched visual-tactile feedback, and walking with
two EEG-controlled robotic actuators, including a
custom-designed lower limb exoskeleton capable of delivering
tactile feedback to subjects. Following 12 months of
training with this paradigm, all eight patients experienced
neurological improvements in somatic sensation (pain
localization, fine/crude touch, and proprioceptive sensing)
in multiple dermatomes. Patients also regained voluntary
motor control in key muscles below the SCI level, as
measured by EMGs, resulting in marked improvement in their
walking index. As a result, 50% of these patients were
upgraded to an incomplete paraplegia classification.
Neurological recovery was paralleled by the reemergence of
lower limb motor imagery at cortical level. We hypothesize
that this unprecedented neurological recovery results from
both cortical and spinal cord plasticity triggered by
long-term BMI usage.},
Doi = {10.1038/srep30383},
Key = {fds323339}
}
@article{fds323336,
Author = {Yin, A and An, J and Lehew, G and Lebedev, MA and Nicolelis,
MAL},
Title = {An automatic experimental apparatus to study arm reaching in
New World monkeys.},
Journal = {J Neurosci Methods},
Volume = {264},
Pages = {57-64},
Year = {2016},
Month = {May},
url = {http://dx.doi.org/10.1016/j.jneumeth.2016.02.017},
Abstract = {BACKGROUND: Several species of the New World monkeys have
been used as experimental models in biomedical and
neurophysiological research. However, a method for
controlled arm reaching tasks has not been developed for
these species. NEW METHOD: We have developed a fully
automated, pneumatically driven, portable, and
reconfigurable experimental apparatus for arm-reaching tasks
suitable for these small primates. RESULTS: We have utilized
the apparatus to train two owl monkeys in a visually-cued
arm-reaching task. Analysis of neural recordings
demonstrates directional tuning of the M1 neurons.
COMPARISON WITH EXISTING METHOD(S): Our apparatus allows
automated control, freeing the experimenter from manual
experiments. CONCLUSION: The presented apparatus provides a
valuable tool for conducting neurophysiological research on
New World monkeys.},
Doi = {10.1016/j.jneumeth.2016.02.017},
Key = {fds323336}
}
@article{fds323337,
Author = {Rajangam, S and Tseng, P-H and Yin, A and Lehew, G and Schwarz, D and Lebedev, MA and Nicolelis, MAL},
Title = {Wireless Cortical Brain-Machine Interface for Whole-Body
Navigation in Primates.},
Journal = {Scientific Reports},
Volume = {6},
Pages = {22170},
Year = {2016},
Month = {March},
url = {http://dx.doi.org/10.1038/srep22170},
Abstract = {Several groups have developed brain-machine-interfaces
(BMIs) that allow primates to use cortical activity to
control artificial limbs. Yet, it remains unknown whether
cortical ensembles could represent the kinematics of
whole-body navigation and be used to operate a BMI that
moves a wheelchair continuously in space. Here we show that
rhesus monkeys can learn to navigate a robotic wheelchair,
using their cortical activity as the main control signal.
Two monkeys were chronically implanted with multichannel
microelectrode arrays that allowed wireless recordings from
ensembles of premotor and sensorimotor cortical neurons.
Initially, while monkeys remained seated in the robotic
wheelchair, passive navigation was employed to train a
linear decoder to extract 2D wheelchair kinematics from
cortical activity. Next, monkeys employed the wireless BMI
to translate their cortical activity into the robotic
wheelchair's translational and rotational velocities. Over
time, monkeys improved their ability to navigate the
wheelchair toward the location of a grape reward. The
navigation was enacted by populations of cortical neurons
tuned to whole-body displacement. During practice with the
apparatus, we also noticed the presence of a cortical
representation of the distance to reward location. These
results demonstrate that intracranial BMIs could restore
whole-body mobility to severely paralyzed patients in the
future.},
Doi = {10.1038/srep22170},
Key = {fds323337}
}
@article{fds323338,
Author = {Hartmann, K and Thomson, EE and Zea, I and Yun, R and Mullen, P and Canarick, J and Huh, A and Nicolelis, MAL},
Title = {Embedding a Panoramic Representation of Infrared Light in
the Adult Rat Somatosensory Cortex through a Sensory
Neuroprosthesis.},
Journal = {Journal of Neuroscience},
Volume = {36},
Number = {8},
Pages = {2406-2424},
Year = {2016},
Month = {February},
url = {http://dx.doi.org/10.1523/JNEUROSCI.3285-15.2016},
Abstract = {Can the adult brain assimilate a novel, topographically
organized, sensory modality into its perceptual repertoire?
To test this, we implemented a microstimulation-based
neuroprosthesis that rats used to discriminate among
infrared (IR) light sources. This system continuously
relayed information from four IR sensors that were
distributed to provide a panoramic view of IR sources, into
primary somatosensory cortex (S1). Rats learned to
discriminate the location of IR sources in <4 d. Animals in
which IR information was delivered in spatial register with
whisker topography learned the task more quickly. Further,
in animals that had learned to use the prosthesis, altering
the topographic mapping from IR sensor to stimulating
electrode had immediate deleterious effects on
discrimination performance. Multielectrode recordings
revealed that S1 neurons had multimodal (tactile/IR)
receptive fields, with clear preferences for those stimuli
most likely to be delivered during the task. Neuronal
populations predicted, with high accuracy, which stimulation
pattern was present in small (75 ms) time windows.
Surprisingly, when identical microstimulation patterns were
delivered during an unrelated task, cortical activity in S1
was strongly suppressed. Overall, these results show that
the adult mammalian neocortex can readily absorb completely
new information sources into its representational
repertoire, and use this information in the production of
adaptive behaviors.},
Doi = {10.1523/JNEUROSCI.3285-15.2016},
Key = {fds323338}
}
@article{fds291332,
Author = {Pais-Vieira, M and Chiuffa, G and Lebedev, M and Yadav, A and Nicolelis,
MAL},
Title = {Corrigendum: Building an organic computing device with
multiple interconnected brains.},
Journal = {Scientific Reports},
Volume = {5},
Pages = {14937},
Year = {2015},
Month = {October},
url = {http://dx.doi.org/10.1038/srep14937},
Doi = {10.1038/srep14937},
Key = {fds291332}
}
@article{fds275246,
Author = {Pais-Vieira, M and Kunicki, C and Tseng, P-H and Martin, J and Lebedev,
M and Nicolelis, MAL},
Title = {Cortical and thalamic contributions to response dynamics
across layers of the primary somatosensory cortex during
tactile discrimination.},
Journal = {J Neurophysiol},
Volume = {114},
Number = {3},
Pages = {1652-1676},
Year = {2015},
Month = {September},
ISSN = {0022-3077},
url = {http://dx.doi.org/10.1152/jn.00108.2015},
Abstract = {Tactile information processing in the rodent primary
somatosensory cortex (S1) is layer specific and involves
modulations from both thalamocortical and cortico-cortical
loops. However, the extent to which these loops influence
the dynamics of the primary somatosensory cortex while
animals execute tactile discrimination remains largely
unknown. Here, we describe neural dynamics of S1 layers
across the multiple epochs defining a tactile discrimination
task. We observed that neuronal ensembles within different
layers of the S1 cortex exhibited significantly distinct
neurophysiological properties, which constantly changed
across the behavioral states that defined a tactile
discrimination. Neural dynamics present in supragranular and
granular layers generally matched the patterns observed in
the ventral posterior medial nucleus of the thalamus (VPM),
whereas the neural dynamics recorded from infragranular
layers generally matched the patterns from the posterior
nucleus of the thalamus (POM). Selective inactivation of
contralateral S1 specifically switched infragranular neural
dynamics from POM-like to those resembling VPM neurons.
Meanwhile, ipsilateral M1 inactivation profoundly modulated
the firing suppression observed in infragranular layers.
This latter effect was counterbalanced by contralateral S1
block. Tactile stimulus encoding was layer specific and
selectively affected by M1 or contralateral S1 inactivation.
Lastly, causal information transfer occurred between all
neurons in all S1 layers but was maximal from infragranular
to the granular layer. These results suggest that tactile
information processing in the S1 of awake behaving rodents
is layer specific and state dependent and that its dynamics
depend on the asynchronous convergence of modulations
originating from ipsilateral M1 and contralateral
S1.},
Doi = {10.1152/jn.00108.2015},
Key = {fds275246}
}
@article{fds275247,
Author = {Pais-Vieira, M and Chiuffa, G and Lebedev, M and Yadav, A and Nicolelis,
MAL},
Title = {Building an organic computing device with multiple
interconnected brains.},
Journal = {Scientific Reports},
Volume = {5},
Pages = {11869},
Year = {2015},
Month = {July},
url = {http://dx.doi.org/10.1038/srep11869},
Abstract = {Recently, we proposed that Brainets, i.e. networks formed by
multiple animal brains, cooperating and exchanging
information in real time through direct brain-to-brain
interfaces, could provide the core of a new type of
computing device: an organic computer. Here, we describe the
first experimental demonstration of such a Brainet, built by
interconnecting four adult rat brains. Brainets worked by
concurrently recording the extracellular electrical activity
generated by populations of cortical neurons distributed
across multiple rats chronically implanted with
multi-electrode arrays. Cortical neuronal activity was
recorded and analyzed in real time, and then delivered to
the somatosensory cortices of other animals that
participated in the Brainet using intracortical
microstimulation (ICMS). Using this approach, different
Brainet architectures solved a number of useful
computational problems, such as discrete classification,
image processing, storage and retrieval of tactile
information, and even weather forecasting. Brainets
consistently performed at the same or higher levels than
single rats in these tasks. Based on these findings, we
propose that Brainets could be used to investigate animal
social behaviors as well as a test bed for exploring the
properties and potential applications of organic
computers.},
Doi = {10.1038/srep11869},
Key = {fds275247}
}
@article{fds304109,
Author = {Ramakrishnan, A and Ifft, PJ and Pais-Vieira, M and Byun, YW and Zhuang,
KZ and Lebedev, MA and Nicolelis, MAL},
Title = {Computing Arm Movements with a Monkey Brainet.},
Journal = {Scientific Reports},
Volume = {5},
Pages = {10767},
Year = {2015},
Month = {July},
url = {http://dx.doi.org/10.1038/srep10767},
Abstract = {Traditionally, brain-machine interfaces (BMIs) extract motor
commands from a single brain to control the movements of
artificial devices. Here, we introduce a Brainet that
utilizes very-large-scale brain activity (VLSBA) from two
(B2) or three (B3) nonhuman primates to engage in a common
motor behaviour. A B2 generated 2D movements of an avatar
arm where each monkey contributed equally to X and Y
coordinates; or one monkey fully controlled the X-coordinate
and the other controlled the Y-coordinate. A B3 produced arm
movements in 3D space, while each monkey generated movements
in 2D subspaces (X-Y, Y-Z, or X-Z). With long-term training
we observed increased coordination of behavior, increased
correlations in neuronal activity between different brains,
and modifications to neuronal representation of the motor
plan. Overall, performance of the Brainet improved owing to
collective monkey behaviour. These results suggest that
primate brains can be integrated into a Brainet, which
self-adapts to achieve a common motor goal.},
Doi = {10.1038/srep10767},
Key = {fds304109}
}
@article{fds304110,
Author = {Rajangam, S and Tseng, P-H and Yin, A and Lebedev, MA and Nicolelis,
MAL},
Title = {Direct Cortical Control of Primate Whole-Body Navigation in
a Mobile Robotic Wheelchair},
Year = {2015},
Month = {April},
url = {http://arxiv.org/abs/1504.02496v1},
Abstract = {We and others have previously developed brain-machine-interfaces
(BMIs), which allowed ensembles of cortical neurons to
control artificial limbs (1-4). However, it is unclear
whether cortical ensembles could operate a BMI for
whole-body navigation. Here we show that rhesus monkeys can
learn to navigate a robotic wheelchair while seated on top
of it, and using their cortical activity as the robot
control signal. Two monkeys were chronically implanted with
multichannel electrode arrays which simultaneously sampled
activity of roughly 150 premotor and sensorimotor cortex
neurons per monkey. This neuronal ensemble activity was
transformed by a linear decoder into the robotic
wheelchair's translational and rotational velocities. During
several weeks of training, monkeys significantly improved
their ability to navigate the wheelchair toward the location
of a food reward. The navigation was enacted by ensemble
modulations attuned to the whole-body displacements, and
also to the distance to the food location. These results
demonstrate that intracranial BMIs could restore whole-body
mobility to severely paralyzed patients in the
future.},
Key = {fds304110}
}
@article{fds275249,
Author = {Zhuang, KZ and Lebedev, MA and Nicolelis, MAL},
Title = {Joint cross-correlation analysis reveals complex,
time-dependent functional relationship between cortical
neurons and arm electromyograms.},
Journal = {J Neurophysiol},
Volume = {112},
Number = {11},
Pages = {2865-2887},
Year = {2014},
Month = {December},
ISSN = {0022-3077},
url = {http://dx.doi.org/10.1152/jn.00031.2013},
Abstract = {Correlation between cortical activity and electromyographic
(EMG) activity of limb muscles has long been a subject of
neurophysiological studies, especially in terms of
corticospinal connectivity. Interest in this issue has
recently increased due to the development of brain-machine
interfaces with output signals that mimic muscle force. For
this study, three monkeys were implanted with multielectrode
arrays in multiple cortical areas. One monkey performed
self-timed touch pad presses, whereas the other two executed
arm reaching movements. We analyzed the dynamic relationship
between cortical neuronal activity and arm EMGs using a
joint cross-correlation (JCC) analysis that evaluated
trial-by-trial correlation as a function of time intervals
within a trial. JCCs revealed transient correlations between
the EMGs of multiple muscles and neural activity in motor,
premotor and somatosensory cortical areas. Matching results
were obtained using spike-triggered averages corrected by
subtracting trial-shuffled data. Compared with
spike-triggered averages, JCCs more readily revealed dynamic
changes in cortico-EMG correlations. JCCs showed that
correlation peaks often sharpened around movement times and
broadened during delay intervals. Furthermore, JCC patterns
were directionally selective for the arm-reaching task. We
propose that such highly dynamic, task-dependent and
distributed relationships between cortical activity and EMGs
should be taken into consideration for future brain-machine
interfaces that generate EMG-like signals.},
Doi = {10.1152/jn.00031.2013},
Key = {fds275249}
}
@article{fds275248,
Author = {Santana, MB and Halje, P and Simplício, H and Richter, U and Freire,
MAM and Petersson, P and Fuentes, R and Nicolelis,
MAL},
Title = {Spinal cord stimulation alleviates motor deficits in a
primate model of Parkinson disease.},
Journal = {Neuron},
Volume = {84},
Number = {4},
Pages = {716-722},
Year = {2014},
Month = {November},
ISSN = {0896-6273},
url = {http://dx.doi.org/10.1016/j.neuron.2014.08.061},
Abstract = {Although deep brain electrical stimulation can alleviate the
motor symptoms of Parkinson disease (PD), just a small
fraction of patients with PD can take advantage of this
procedure due to its invasive nature. A significantly less
invasive method--epidural spinal cord stimulation (SCS)--has
been suggested as an alternative approach for symptomatic
treatment of PD. However, the mechanisms underlying motor
improvements through SCS are unknown. Here, we show that SCS
reproducibly alleviates motor deficits in a primate model of
PD. Simultaneous neuronal recordings from multiple
structures of the cortico-basal ganglia-thalamic loop in
parkinsonian monkeys revealed abnormal highly synchronized
neuronal activity within each of these structures and
excessive functional coupling among them. SCS disrupted this
pathological circuit behavior in a manner that mimics the
effects caused by pharmacological dopamine replacement
therapy or deep brain stimulation. These results suggest
that SCS should be considered as an additional treatment
option for patients with PD.},
Doi = {10.1016/j.neuron.2014.08.061},
Key = {fds275248}
}
@article{fds275250,
Author = {Thomson, E and Lou, J and Sylvester, K and McDonough, A and Tica, S and Nicolelis, MA},
Title = {Basal forebrain dynamics during a tactile discrimination
task.},
Journal = {J Neurophysiol},
Volume = {112},
Number = {5},
Pages = {1179-1191},
Year = {2014},
Month = {September},
ISSN = {0022-3077},
url = {http://dx.doi.org/10.1152/jn.00040.2014},
Abstract = {The nucleus basalis (NB) is a cholinergic neuromodulatory
structure that projects liberally to the entire cortical
mantle and regulates information processing in all cortical
layers. Here, we recorded activity from populations of
single units in the NB as rats performed a whisker-dependent
tactile discrimination task. Over 80% of neurons responded
with significant modulation in at least one phase of the
task. Such activity started before stimulus onset and
continued for seconds after reward delivery. Firing rates
monotonically increased with reward magnitude during the
task, suggesting that NB neurons are not indicating the
absolute deviation from expected reward amounts. Individual
neurons also encoded significant amounts of information
about stimulus identity. Such robust coding was not present
when the same stimuli were delivered to lightly anesthetized
animals, suggesting that the NB neurons contain a
sensorimotor, rather than purely sensory or motor,
representation of the environment. Overall, these results
support the hypothesis that neurons in the NB provide a
value-laden representation of the sensorimotor state of the
animal as it engages in significant behavioral
tasks.},
Doi = {10.1152/jn.00040.2014},
Key = {fds275250}
}
@article{fds275253,
Author = {Schwarz, DA and Lebedev, MA and Hanson, TL and Dimitrov, DF and Lehew,
G and Meloy, J and Rajangam, S and Subramanian, V and Ifft, PJ and Li, Z and Ramakrishnan, A and Tate, A and Zhuang, KZ and Nicolelis,
MAL},
Title = {Chronic, wireless recordings of large-scale brain activity
in freely moving rhesus monkeys.},
Journal = {Nat Methods},
Volume = {11},
Number = {6},
Pages = {670-676},
Year = {2014},
Month = {June},
ISSN = {1548-7091},
url = {http://dx.doi.org/10.1038/nmeth.2936},
Abstract = {Advances in techniques for recording large-scale brain
activity contribute to both the elucidation of
neurophysiological principles and the development of
brain-machine interfaces (BMIs). Here we describe a
neurophysiological paradigm for performing tethered and
wireless large-scale recordings based on movable volumetric
three-dimensional (3D) multielectrode implants. This
approach allowed us to isolate up to 1,800 neurons (units)
per animal and simultaneously record the extracellular
activity of close to 500 cortical neurons, distributed
across multiple cortical areas, in freely behaving rhesus
monkeys. The method is expandable, in principle, to
thousands of simultaneously recorded channels. It also
allows increased recording longevity (5 consecutive years)
and recording of a broad range of behaviors, such as social
interactions, and BMI paradigms in freely moving primates.
We propose that wireless large-scale recordings could have a
profound impact on basic primate neurophysiology research
while providing a framework for the development and testing
of clinically relevant neuroprostheses.},
Doi = {10.1038/nmeth.2936},
Key = {fds275253}
}
@article{fds275256,
Author = {Yadav, AP and Fuentes, R and Zhang, H and Vinholo, T and Wang, C-H and Freire, MAM and Nicolelis, MAL},
Title = {Chronic spinal cord electrical stimulation protects against
6-hydroxydopamine lesions.},
Journal = {Scientific Reports},
Volume = {4},
Pages = {3839},
Year = {2014},
Month = {January},
url = {http://dx.doi.org/10.1038/srep03839},
Abstract = {Although L-dopa continues to be the gold standard for
treating motor symptoms of Parkinson's disease (PD), it
presents long-term complications. Deep brain stimulation is
effective, but only a small percentage of idiopathic PD
patients are eligible. Based on results in animal models and
a handful of patients, dorsal column stimulation (DCS) has
been proposed as a potential therapy for PD. To date, the
long-term effects of DCS in animal models have not been
quantified. Here, we report that DCS applied twice a week in
rats treated with bilateral 6-OHDA striatal infusions led to
a significant improvement in symptoms. DCS-treated rats
exhibited a higher density of dopaminergic innervation in
the striatum and higher neuronal cell count in the
substantia nigra pars compacta compared to a control group.
These results suggest that DCS has a chronic therapeutical
and neuroprotective effect, increasing its potential as a
new clinical option for treating PD patients.},
Doi = {10.1038/srep03839},
Key = {fds275256}
}
@article{fds275252,
Author = {Schwarz, DA and Lebedev, MA and Hanson, TL and Dimitrov, DF and Lehew,
G and Meloy, J and Rajangam, S and Subramanian, V and Ifft, PJ and Li, Z and Ramakrishnan, A and Tate, A and Zhuang, KZ and Nicolelis,
MAL},
Title = {Chronic, wireless recordings of large-scale brain activity
in freely moving rhesus monkeys},
Journal = {Nature Methods},
Volume = {11},
Number = {6},
Pages = {670-676},
Year = {2014},
Month = {January},
ISSN = {1548-7091},
url = {http://dx.doi.org/10.1038/nmeth.2936},
Abstract = {Advances in techniques for recording large-scale brain
activity contribute to both the elucidation of
neurophysiological principles and the development of
brain-machine interfaces (BMIs). Here we describe a
neurophysiological paradigm for performing tethered and
wireless large-scale recordings based on movable volumetric
three-dimensional (3D) multielectrode implants. This
approach allowed us to isolate up to 1,800 neurons (units)
per animal and simultaneously record the extracellular
activity of close to 500 cortical neurons, distributed
across multiple cortical areas, in freely behaving rhesus
monkeys. The method is expandable, in principle, to
thousands of simultaneously recorded channels. It also
allows increased recording longevity (5 consecutive years)
and recording of a broad range of behaviors, such as social
interactions, and BMI paradigms in freely moving primates.
We propose that wireless large-scale recordings could have a
profound impact on basic primate neurophysiology research
while providing a framework for the development and testing
of clinically relevant neuroprostheses. © 2014 Nature
America, Inc.},
Doi = {10.1038/nmeth.2936},
Key = {fds275252}
}
@article{fds275251,
Author = {Zacksenhouse, M and Lebedev, MA and Nicolelis,
MAL},
Title = {Signal-independent timescale analysis (SITA) and its
application for neural coding during reaching and
walking.},
Journal = {Frontiers in Computational Neuroscience},
Volume = {8},
Pages = {91},
Year = {2014},
url = {http://dx.doi.org/10.3389/fncom.2014.00091},
Abstract = {What are the relevant timescales of neural encoding in the
brain? This question is commonly investigated with respect
to well-defined stimuli or actions. However, neurons often
encode multiple signals, including hidden or internal, which
are not experimentally controlled, and thus excluded from
such analysis. Here we consider all rate modulations as the
signal, and define the rate-modulations signal-to-noise
ratio (RM-SNR) as the ratio between the variance of the rate
and the variance of the neuronal noise. As the bin-width
increases, RM-SNR increases while the update rate decreases.
This tradeoff is captured by the ratio of RM-SNR to
bin-width, and its variations with the bin-width reveal the
timescales of neural activity. Theoretical analysis and
simulations elucidate how the interactions between the
recovery properties of the unit and the spectral content of
the encoded signals shape this ratio and determine the
timescales of neural coding. The resulting
signal-independent timescale analysis (SITA) is applied to
investigate timescales of neural activity recorded from the
motor cortex of monkeys during: (i) reaching experiments
with Brain-Machine Interface (BMI), and (ii) locomotion
experiments at different speeds. Interestingly, the
timescales during BMI experiments did not change
significantly with the control mode or training. During
locomotion, the analysis identified units whose timescale
varied consistently with the experimentally controlled speed
of walking, though the specific timescale reflected also the
recovery properties of the unit. Thus, the proposed method,
SITA, characterizes the timescales of neural encoding and
how they are affected by the motor task, while accounting
for all rate modulations.},
Doi = {10.3389/fncom.2014.00091},
Key = {fds275251}
}
@article{fds364107,
Author = {Nicolelis, MAL},
Title = {Brain-to-Brain Interfaces: When Reality Meets Science
Fiction.},
Journal = {Cerebrum : the Dana Forum on Brain Science},
Volume = {2014},
Pages = {13},
Year = {2014},
Abstract = {Every memory that we have, act that we perform, and feeling
that we experience creates brainstorms—interactions of
millions of cells that produce electrical signals.
Neuroscientists are now able to record those signals,
extract the kind of motor commands that the brain is about
to produce, and communicate the commands to machines that
can understand them and facilitate movement in the human
body. Research in this area has the potential to help
paraplegics and others suffering from spinal-cord injuries
to control machines with their thoughts and to bolster their
ability to get around.},
Key = {fds364107}
}
@article{fds275259,
Author = {Ifft, PJ and Shokur, S and Li, Z and Lebedev, MA and Nicolelis,
MAL},
Title = {A brain-machine interface enables bimanual arm movements in
monkeys.},
Journal = {Sci Transl Med},
Volume = {5},
Number = {210},
Pages = {210ra154},
Year = {2013},
Month = {November},
url = {http://www.ncbi.nlm.nih.gov/pubmed/24197735},
Abstract = {Brain-machine interfaces (BMIs) are artificial systems that
aim to restore sensation and movement to paralyzed patients.
So far, BMIs have enabled only one arm to be moved at a
time. Control of bimanual arm movements remains a major
challenge. We have developed and tested a bimanual BMI that
enables rhesus monkeys to control two avatar arms
simultaneously. The bimanual BMI was based on the
extracellular activity of 374 to 497 neurons recorded from
several frontal and parietal cortical areas of both cerebral
hemispheres. Cortical activity was transformed into
movements of the two arms with a decoding algorithm called a
fifth-order unscented Kalman filter (UKF). The UKF was
trained either during a manual task performed with two
joysticks or by having the monkeys passively observe the
movements of avatar arms. Most cortical neurons changed
their modulation patterns when both arms were engaged
simultaneously. Representing the two arms jointly in a
single UKF decoder resulted in improved decoding performance
compared with using separate decoders for each arm. As the
animals' performance in bimanual BMI control improved over
time, we observed widespread plasticity in frontal and
parietal cortical areas. Neuronal representation of the
avatar and reach targets was enhanced with learning, whereas
pairwise correlations between neurons initially increased
and then decreased. These results suggest that cortical
networks may assimilate the two avatar arms through BMI
control. These findings should help in the design of more
sophisticated BMIs capable of enabling bimanual motor
control in human patients.},
Doi = {10.1126/scitranslmed.3006159},
Key = {fds275259}
}
@article{fds275260,
Author = {Shokur, S and O'Doherty, JE and Winans, JA and Bleuler, H and Lebedev,
MA and Nicolelis, MAL},
Title = {Expanding the primate body schema in sensorimotor cortex by
virtual touches of an avatar.},
Journal = {Proc Natl Acad Sci U S A},
Volume = {110},
Number = {37},
Pages = {15121-15126},
Year = {2013},
Month = {September},
ISSN = {0027-8424},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000324125100068&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {The brain representation of the body, called the body
schema, is susceptible to plasticity. For instance, subjects
experiencing a rubber hand illusion develop a sense of
ownership of a mannequin hand when they view it being
touched while tactile stimuli are simultaneously applied to
their own hand. Here, the cortical basis of such an
embodiment was investigated through concurrent recordings
from primary somatosensory (i.e., S1) and motor (i.e., M1)
cortical neuronal ensembles while two monkeys observed an
avatar arm being touched by a virtual ball. Following a
period when virtual touches occurred synchronously with
physical brushes of the monkeys' arms, neurons in S1 and M1
started to respond to virtual touches applied alone.
Responses to virtual touch occurred 50 to 70 ms later than
to physical touch, consistent with the involvement of
polysynaptic pathways linking the visual cortex to S1 and
M1. We propose that S1 and M1 contribute to the rubber hand
illusion and that, by taking advantage of plasticity in
these areas, patients may assimilate neuroprosthetic limbs
as parts of their body schema.},
Doi = {10.1073/pnas.1308459110},
Key = {fds275260}
}
@article{fds275269,
Author = {Dzirasa, K and Kumar, S and Sachs, BD and Caron, MG and Nicolelis,
MAL},
Title = {Cortical-amygdalar circuit dysfunction in a genetic mouse
model of serotonin deficiency.},
Journal = {Journal of Neuroscience},
Volume = {33},
Number = {10},
Pages = {4505-4513},
Year = {2013},
Month = {March},
url = {http://www.ncbi.nlm.nih.gov/pubmed/23467366},
Abstract = {Although the majority of first-line antidepressants increase
brain serotonin and rare polymorphisms in tryptophan
hydroxlase-2 (Tph2), the rate-limiting enzyme in the brain
serotonin synthesis pathway, have been identified in cohorts
of subjects with major depressive disorder, the circuit
level alterations that results from serotonergic
hypofunction remain poorly understood. Here we use chronic
multicircuit neurophysiological recordings to characterize
functional interactions across cortical and limbic circuits
in mice engineered to express a human loss-of-function
depression allele Tph2-(R441H) [Tph2 knockin (Tph2KI)]. Our
results show that Tph2KI mice exhibit increased
intra-network synchrony within medial prefrontal cortex
(mPFC) and basal amygdala (AMY) and increased inter-network
synchrony between these two brain networks. Moreover, we
demonstrate that chronic treatment with fluoxetine reverses
several of the circuit alterations observed within Tph2KI
mice. Together, our findings establish a functional link
between functional hyposerotonergia and altered mPFC-AMY
network dynamics.},
Doi = {10.1523/JNEUROSCI.4891-12.2013},
Key = {fds275269}
}
@article{fds275267,
Author = {Pais-Vieira, M and Lebedev, MA and Wiest, MC and Nicolelis,
MAL},
Title = {Simultaneous top-down modulation of the primary
somatosensory cortex and thalamic nuclei during active
tactile discrimination.},
Journal = {Journal of Neuroscience},
Volume = {33},
Number = {9},
Pages = {4076-4093},
Year = {2013},
Month = {February},
ISSN = {0270-6474},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000315588000033&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {The rat somatosensory system contains multiple
thalamocortical loops (TCLs) that altogether process, in
fundamentally different ways, tactile stimuli delivered
passively or actively sampled. To elucidate potential
top-down mechanisms that govern TCL processing in awake,
behaving animals, we simultaneously recorded neuronal
ensemble activity across multiple cortical and thalamic
areas while rats performed an active aperture discrimination
task. Single neurons located in the primary somatosensory
cortex (S1), the ventroposterior medial, and the posterior
medial thalamic nuclei of the trigeminal somatosensory
pathways exhibited prominent anticipatory firing modulations
before the whiskers touching the aperture edges. This
cortical and thalamic anticipatory firing could not be
explained by whisker movements or whisker stimulation,
because neither trigeminal ganglion sensory-evoked responses
nor EMG activity were detected during the same period. Both
thalamic and S1 anticipatory activity were predictive of the
animal's discrimination accuracy. Inactivation of the
primary motor cortex (M1) with muscimol affected
anticipatory patterns in S1 and the thalamus, and impaired
the ability to predict the animal's performance accuracy
based on thalamocortical anticipatory activity. These
findings suggest that neural processing in TCLs is launched
in anticipation of whisker contact with objects, depends on
top-down effects generated in part by M1 activity, and
cannot be explained by the classical feedforward model of
the rat trigeminal system.},
Doi = {10.1523/JNEUROSCI.1659-12.2013},
Key = {fds275267}
}
@article{fds275266,
Author = {Thomson, EE and Carra, R and Nicolelis, MAL},
Title = {Perceiving invisible light through a somatosensory cortical
prosthesis.},
Journal = {Nature Communications},
Volume = {4},
Pages = {1482},
Year = {2013},
ISSN = {2041-1723},
url = {http://dx.doi.org/10.1038/ncomms2497},
Abstract = {Sensory neuroprostheses show great potential for alleviating
major sensory deficits. It is not known, however, whether
such devices can augment the subject's normal perceptual
range. Here we show that adult rats can learn to perceive
otherwise invisible infrared light through a neuroprosthesis
that couples the output of a head-mounted infrared sensor to
their somatosensory cortex (S1) via intracortical
microstimulation. Rats readily learn to use this new
information source, and generate active exploratory
strategies to discriminate among infrared signals in their
environment. S1 neurons in these infrared-perceiving rats
respond to both whisker deflection and intracortical
microstimulation, suggesting that the infrared
representation does not displace the original tactile
representation. Hence, sensory cortical prostheses, in
addition to restoring normal neurological functions, may
serve to expand natural perceptual capabilities in
mammals.},
Doi = {10.1038/ncomms2497},
Key = {fds275266}
}
@article{fds275268,
Author = {Pais-Vieira, M and Lebedev, M and Kunicki, C and Wang, J and Nicolelis,
MAL},
Title = {A brain-to-brain interface for real-time sharing of
sensorimotor information.},
Journal = {Scientific Reports},
Volume = {3},
Pages = {1319},
Year = {2013},
ISSN = {2045-2322},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000315563400001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {A brain-to-brain interface (BTBI) enabled a real-time
transfer of behaviorally meaningful sensorimotor information
between the brains of two rats. In this BTBI, an "encoder"
rat performed sensorimotor tasks that required it to select
from two choices of tactile or visual stimuli. While the
encoder rat performed the task, samples of its cortical
activity were transmitted to matching cortical areas of a
"decoder" rat using intracortical microstimulation (ICMS).
The decoder rat learned to make similar behavioral
selections, guided solely by the information provided by the
encoder rat's brain. These results demonstrated that a
complex system was formed by coupling the animals' brains,
suggesting that BTBIs can enable dyads or networks of
animal's brains to exchange, process, and store information
and, hence, serve as the basis for studies of novel types of
social interaction and for biological computing
devices.},
Doi = {10.1038/srep01319},
Key = {fds275268}
}
@article{fds275345,
Author = {Medina, LE and Lebedev, MA and O'Doherty, JE and Nicolelis,
MAL},
Title = {Stochastic facilitation of artificial tactile sensation in
primates.},
Journal = {Journal of Neuroscience},
Volume = {32},
Number = {41},
Pages = {14271-14275},
Year = {2012},
Month = {October},
ISSN = {0270-6474},
url = {http://dx.doi.org/10.1523/JNEUROSCI.3115-12.2012},
Abstract = {Artificial sensation via electrical or optical stimulation
of brain sensory areas offers a promising treatment for
sensory deficits. For a brain-machine-brain interface, such
artificial sensation conveys feedback signals from a
sensorized prosthetic limb. The ways neural tissue can be
stimulated to evoke artificial sensation and the parameter
space of such stimulation, however, remain largely
unexplored. Here we investigated whether stochastic
facilitation (SF) could enhance an artificial tactile
sensation produced by intracortical microstimulation (ICMS).
Two rhesus monkeys learned to use a virtual hand, which they
moved with a joystick, to explore virtual objects on a
computer screen. They sought an object associated with a
particular artificial texture (AT) signaled by a periodic
ICMS pattern delivered to the primary somatosensory cortex
(S1) through a pair of implanted electrodes. During each
behavioral trial, aperiodic ICMS (i.e., noise) of randomly
chosen amplitude was delivered to S1 through another
electrode pair implanted 1 mm away from the site of AT
delivery. Whereas high-amplitude noise worsened AT
detection, moderate noise clearly improved the detection of
weak signals, significantly raising the proportion of
correct trials. These findings suggest that SF could be used
to enhance prosthetic sensation.},
Doi = {10.1523/JNEUROSCI.3115-12.2012},
Key = {fds275345}
}
@article{fds275344,
Author = {Nicolelis, MAL},
Title = {Mind in motion},
Journal = {Scientific American},
Volume = {307},
Number = {3},
Pages = {44-49},
Publisher = {Springer Nature},
Year = {2012},
Month = {September},
ISSN = {0036-8733},
url = {http://dx.doi.org/10.1038/scientificamerican0912-44},
Doi = {10.1038/scientificamerican0912-44},
Key = {fds275344}
}
@article{fds275370,
Author = {Nicolelis, MAL},
Title = {Mind in motion.},
Journal = {Scientific American},
Volume = {307},
Number = {3},
Pages = {58-63},
Year = {2012},
Month = {September},
ISSN = {0036-8733},
url = {http://dx.doi.org/10.1038/scientificamerican0912-58},
Doi = {10.1038/scientificamerican0912-58},
Key = {fds275370}
}
@article{fds275343,
Author = {Tandon, S and Simon, SA and Nicolelis, MAL},
Title = {Appetitive changes during salt deprivation are paralleled by
widespread neuronal adaptations in nucleus accumbens,
lateral hypothalamus, and central amygdala.},
Journal = {J Neurophysiol},
Volume = {108},
Number = {4},
Pages = {1089-1105},
Year = {2012},
Month = {August},
url = {http://www.ncbi.nlm.nih.gov/pubmed/22572944},
Abstract = {Salt appetite is a goal-directed behavior in which
salt-deprived animals ingest high salt concentrations that
they otherwise find aversive. Because forebrain areas such
as the lateral hypothalamus (LH), central amygdala (CeA),
and nucleus accumbens (NAc) are known to play an important
role in this behavior, we recorded from these areas while
water-deprived (WD) and salt-deprived (SD) rats performed a
two-bottle choice test between 0.5 M salt (NaCl) and 0.4 M
sucrose. In the SD state, the preference ratio for high
molar salt markedly increased. Electrophysiological
recordings analyzed with respect to the onset of licking
clusters revealed the presence of both excitatory and
inhibitory neuronal responses during salt and/or sucrose
consumption. In the NAc, putative medium spiny neurons and
tonically active neurons exhibited excitatory and inhibitory
responses. In all areas, compared with those recorded during
the WD state, neurons recorded during the SD state showed an
increase in the percentage of salt-evoked excitatory
responses and a decrease in the percentage of sucrose-evoked
inhibitory responses, suggesting that a subset of the
neuronal population in these areas codes for the increased
motivational and/or hedonic value of the salt solution. In
addition, in the SD state, the firing of excitatory neurons
in LH and CeA became more synchronized, indicating a greater
functional connectivity between salt-responsive neurons in
these areas. We propose that plastic changes in the
feeding-related neuronal populations of these forebrain
areas arise when changes in metabolic state alter the
hedonic and motivational value of a particular taste
stimulus.},
Doi = {10.1152/jn.00236.2012},
Key = {fds275343}
}
@article{fds275342,
Author = {Hanson, TL and Fuller, AM and Lebedev, MA and Turner, DA and Nicolelis,
MAL},
Title = {Subcortical neuronal ensembles: an analysis of motor task
association, tremor, oscillations, and synchrony in human
patients.},
Journal = {Journal of Neuroscience},
Volume = {32},
Number = {25},
Pages = {8620-8632},
Year = {2012},
Month = {June},
url = {http://www.ncbi.nlm.nih.gov/pubmed/22723703},
Abstract = {Deep brain stimulation (DBS) has expanded as an effective
treatment for motor disorders, providing a valuable
opportunity for intraoperative recording of the spiking
activity of subcortical neurons. The properties of these
neurons and their potential utility in neuroprosthetic
applications are not completely understood. During DBS
surgeries in 25 human patients with either essential tremor
or Parkinson's disease, we acutely recorded the single-unit
activity of 274 ventral intermediate/ventral oralis
posterior motor thalamus (Vim/Vop) neurons and 123
subthalamic nucleus (STN) neurons. These subcortical
neuronal ensembles (up to 23 neurons sampled simultaneously)
were recorded while the patients performed a target-tracking
motor task using a cursor controlled by a haptic glove. We
observed that modulations in firing rate of a substantial
number of neurons in both Vim/Vop and STN represented target
onset, movement onset/direction, and hand tremor. Neurons in
both areas exhibited rhythmic oscillations and pairwise
synchrony. Notably, all tremor-associated neurons exhibited
synchrony within the ensemble. The data further indicate
that oscillatory (likely pathological) neurons and
behaviorally tuned neurons are not distinct but rather form
overlapping sets. Whereas previous studies have reported a
linear relationship between power spectra of neuronal
oscillations and hand tremor, we report a nonlinear
relationship suggestive of complex encoding schemes. Even in
the presence of this pathological activity, linear models
were able to extract motor parameters from ensemble
discharges. Based on these findings, we propose that chronic
multielectrode recordings from Vim/Vop and STN could prove
useful for further studying, monitoring, and even treating
motor disorders.},
Doi = {10.1523/JNEUROSCI.0750-12.2012},
Key = {fds275342}
}
@article{fds275341,
Author = {Hanson, TL and Ómarsson, B and O'Doherty, JE and Peikon, ID and Lebedev, MA and Nicolelis, MAL},
Title = {High-side digitally current controlled biphasic bipolar
microstimulator.},
Journal = {Ieee Trans Neural Syst Rehabil Eng},
Volume = {20},
Number = {3},
Pages = {331-340},
Year = {2012},
Month = {May},
ISSN = {1534-4320},
url = {http://dx.doi.org/10.1109/TNSRE.2012.2187219},
Abstract = {Electrical stimulation of nervous tissue has been
extensively used as both a tool in experimental neuroscience
research and as a method for restoring of neural functions
in patients suffering from sensory and motor disabilities.
In the central nervous system, intracortical
microstimulation (ICMS) has been shown to be an effective
method for inducing or biasing perception, including visual
and tactile sensation. ICMS also holds promise for enabling
brain-machine-brain interfaces (BMBIs) by directly writing
information into the brain. Here we detail the design of a
high-side, digitally current-controlled biphasic, bipolar
microstimulator, and describe the validation of the device
in vivo. As many applications of this technique, including
BMBIs, require recording as well as stimulation, we pay
careful attention to isolation of the stimulus channels and
parasitic current injection. With the realized device and
standard recording hardware-without active artifact
rejection-we are able to observe stimulus artifacts of less
than 2 ms in duration.},
Doi = {10.1109/TNSRE.2012.2187219},
Key = {fds275341}
}
@article{fds275337,
Author = {O'Doherty, JE and Lebedev, MA and Li, Z and Nicolelis,
MAL},
Title = {Virtual active touch using randomly patterned intracortical
microstimulation.},
Journal = {Ieee Trans Neural Syst Rehabil Eng},
Volume = {20},
Number = {1},
Pages = {85-93},
Year = {2012},
Month = {January},
ISSN = {1534-4320},
url = {http://dx.doi.org/10.1109/TNSRE.2011.2166807},
Abstract = {Intracortical microstimulation (ICMS) has promise as a means
for delivering somatosensory feedback in neuroprosthetic
systems. Various tactile sensations could be encoded by
temporal, spatial, or spatiotemporal patterns of ICMS.
However, the applicability of temporal patterns of ICMS to
artificial tactile sensation during active exploration is
unknown, as is the minimum discriminable difference between
temporally modulated ICMS patterns. We trained rhesus
monkeys in an active exploration task in which they
discriminated periodic pulse-trains of ICMS (200 Hz bursts
at a 10 Hz secondary frequency) from pulse trains with the
same average pulse rate, but distorted periodicity (200 Hz
bursts at a variable instantaneous secondary frequency). The
statistics of the aperiodic pulse trains were drawn from a
gamma distribution with mean inter-burst intervals equal to
those of the periodic pulse trains. The monkeys
distinguished periodic pulse trains from aperiodic pulse
trains with coefficients of variation 0.25 or greater.
Reconstruction of movement kinematics, extracted from the
activity of neuronal populations recorded in the
sensorimotor cortex concurrent with the delivery of ICMS
feedback, improved when the recording intervals affected by
ICMS artifacts were removed from analysis. These results add
to the growing evidence that temporally patterned ICMS can
be used to simulate a tactile sense for neuroprosthetic
devices.},
Doi = {10.1109/TNSRE.2011.2166807},
Key = {fds275337}
}
@article{fds275265,
Author = {Ifft, PJ and Lebedev, MA and Nicolelis, MAL},
Title = {Reprogramming movements: Extraction of motor intentions from
cortical ensemble activity when movement goals
change},
Journal = {Frontiers in Neuroengineering},
Number = {JULY},
Year = {2012},
ISSN = {1662-6443},
url = {http://dx.doi.org/10.3389/fneng.2012.00016},
Abstract = {The ability to inhibit unwanted movements and change motor
plans is essential for behaviors of advanced organisms. The
neural mechanisms by which the primate motor system rejects
undesired actions have received much attention during the
last decade, but it is not well understood how this neural
function could be utilized to improve the efficiency of
brain-machine interfaces (BMIs). Here we employed linear
discriminant analysis (LDA) and a Wiener filter to extract
motor plan transitions from the activity of ensembles of
sensorimotor cortex neurons. Two rhesus monkeys, chronically
implanted with multielectrode arrays in primary motor (M1)
and primary sensory (S1) cortices, were overtrained to
produce reaching movements with a joystick towards visual
targets upon their presentation. Then, the behavioral task
was modified to include a distracting target that flashed
for 50, 150 or 250 ms (25% of trials each) followed by the
true target that appeared at a different screen location. In
the remaining 25% of trials, the initial target stayed on
the screen and was the target to be approached. M1 and S1
neuronal activity represented both the true and distracting
targets, even for the shortest duration of the distracting
event. This dual representation persisted both when the
monkey initiated movements towards the distracting target
and then made corrections and when they moved directly
towards the second, true target. The Wiener filter
effectively decoded the location of the true target, whereas
the LDA classifier extracted the location of both targets
from ensembles of 50-250 neurons. Based on these results, we
suggest developing real-time BMIs that inhibit unwanted
movements represented by brain activity while enacting the
desired motor outcome concomitantly. © 2012 Ifft, Lebedev
and Nicolelis.},
Doi = {10.3389/fneng.2012.00016},
Key = {fds275265}
}
@article{fds275339,
Author = {Oliveira-Maia, AJ and de Araujo, IE and Monteiro, C and Workman, V and Galhardo, V and Nicolelis, MAL},
Title = {The insular cortex controls food preferences independently
of taste receptor signaling.},
Journal = {Frontiers in Systems Neuroscience},
Volume = {6},
Number = {MARCH},
Pages = {5},
Year = {2012},
ISSN = {1662-5137},
url = {http://dx.doi.org/10.3389/fnsys.2012.00005},
Abstract = {The insular cortex (IC) contains the primary sensory cortex
for oral chemosensation including gustation, and its
integrity is required for appropriate control of feeding
behavior. However, it remains unknown whether the role of
this brain area in food selection relies on the presence of
peripheral taste input. Using multielectrode recordings, we
found that the responses of populations of neurons in the IC
of freely licking, sweet-blind Trpm5(-/-) mice are modulated
by the rewarding postingestive effects of sucrose. FOS
immunoreactivity analyses revealed that these responses are
restricted to the dorsal insula. Furthermore, bilateral
lesions in this area abolished taste-independent preferences
for sucrose that can be conditioned in these Trpm5(-/-)
animals while preserving their ability to detect sucrose.
Overall, these findings demonstrate that, even in the
absence of peripheral taste input, IC regulates food choices
based on postingestive signals.},
Doi = {10.3389/fnsys.2012.00005},
Key = {fds275339}
}
@article{fds275340,
Author = {Ifft, PJ and Lebedev, MA and Nicolelis, MAL},
Title = {Reprogramming movements: extraction of motor intentions from
cortical ensemble activity when movement goals
change.},
Journal = {Frontiers in Neuroengineering},
Volume = {5},
Number = {JULY},
Pages = {16},
Year = {2012},
ISSN = {1662-6443},
url = {http://dx.doi.org/10.3389/fneng.2012.00016},
Abstract = {The ability to inhibit unwanted movements and change motor
plans is essential for behaviors of advanced organisms. The
neural mechanisms by which the primate motor system rejects
undesired actions have received much attention during the
last decade, but it is not well understood how this neural
function could be utilized to improve the efficiency of
brain-machine interfaces (BMIs). Here we employed linear
discriminant analysis (LDA) and a Wiener filter to extract
motor plan transitions from the activity of ensembles of
sensorimotor cortex neurons. Two rhesus monkeys, chronically
implanted with multielectrode arrays in primary motor (M1)
and primary sensory (S1) cortices, were overtrained to
produce reaching movements with a joystick toward visual
targets upon their presentation. Then, the behavioral task
was modified to include a distracting target that flashed
for 50, 150, or 250 ms (25% of trials each) followed by the
true target that appeared at a different screen location. In
the remaining 25% of trials, the initial target stayed on
the screen and was the target to be approached. M1 and S1
neuronal activity represented both the true and distracting
targets, even for the shortest duration of the distracting
event. This dual representation persisted both when the
monkey initiated movements toward the distracting target and
then made corrections and when they moved directly toward
the second, true target. The Wiener filter effectively
decoded the location of the true target, whereas the LDA
classifier extracted the location of both targets from
ensembles of 50-250 neurons. Based on these results, we
suggest developing real-time BMIs that inhibit unwanted
movements represented by brain activity while enacting the
desired motor outcome concomitantly.},
Doi = {10.3389/fneng.2012.00016},
Key = {fds275340}
}
@article{fds275338,
Author = {Li, Z and O'Doherty, JE and Lebedev, MA and Nicolelis,
MAL},
Title = {Adaptive decoding for brain-machine interfaces through
Bayesian parameter updates.},
Journal = {Neural Comput},
Volume = {23},
Number = {12},
Pages = {3162-3204},
Year = {2011},
Month = {December},
url = {http://www.ncbi.nlm.nih.gov/pubmed/21919788},
Abstract = {Brain-machine interfaces (BMIs) transform the activity of
neurons recorded in motor areas of the brain into movements
of external actuators. Representation of movements by
neuronal populations varies over time, during both voluntary
limb movements and movements controlled through BMIs, due to
motor learning, neuronal plasticity, and instability in
recordings. To ensure accurate BMI performance over long
time spans, BMI decoders must adapt to these changes. We
propose the Bayesian regression self-training method for
updating the parameters of an unscented Kalman filter
decoder. This novel paradigm uses the decoder's output to
periodically update its neuronal tuning model in a Bayesian
linear regression. We use two previously known statistical
formulations of Bayesian linear regression: a joint
formulation, which allows fast and exact inference, and a
factorized formulation, which allows the addition and
temporary omission of neurons from updates but requires
approximate variational inference. To evaluate these
methods, we performed offline reconstructions and
closed-loop experiments with rhesus monkeys implanted
cortically with microwire electrodes. Offline
reconstructions used data recorded in areas M1, S1, PMd,
SMA, and PP of three monkeys while they controlled a cursor
using a handheld joystick. The Bayesian regression
self-training updates significantly improved the accuracy of
offline reconstructions compared to the same decoder without
updates. We performed 11 sessions of real-time, closed-loop
experiments with a monkey implanted in areas M1 and S1.
These sessions spanned 29 days. The monkey controlled the
cursor using the decoder with and without updates. The
updates maintained control accuracy and did not require
information about monkey hand movements, assumptions about
desired movements, or knowledge of the intended movement
goals as training signals. These results indicate that
Bayesian regression self-training can maintain BMI control
accuracy over long periods, making clinical neuroprosthetics
more viable.},
Doi = {10.1162/NECO_a_00207},
Key = {fds275338}
}
@article{fds275333,
Author = {Zhang, H and Lin, S-C and Nicolelis, MAL},
Title = {A distinctive subpopulation of medial septal slow-firing
neurons promote hippocampal activation and theta
oscillations.},
Journal = {J Neurophysiol},
Volume = {106},
Number = {5},
Pages = {2749-2763},
Year = {2011},
Month = {November},
url = {http://www.ncbi.nlm.nih.gov/pubmed/21865435},
Abstract = {The medial septum-vertical limb of the diagonal band of
Broca (MSvDB) is important for normal hippocampal functions
and theta oscillations. Although many previous studies have
focused on understanding how MSVDB neurons fire rhythmic
bursts to pace hippocampal theta oscillations, a significant
portion of MSVDB neurons are slow-firing and thus do not
pace theta oscillations. The function of these MSVDB
neurons, especially their role in modulating hippocampal
activity, remains unknown. We recorded MSVDB neuronal
ensembles in behaving rats, and identified a distinct
physiologically homogeneous subpopulation of slow-firing
neurons (overall firing <4 Hz) that shared three features:
1) much higher firing rate during rapid eye movement sleep
than during slow-wave (SW) sleep; 2) temporary activation
associated with transient arousals during SW sleep; 3) brief
responses (latency 15∼30 ms) to auditory stimuli. Analysis
of the fine temporal relationship of their spiking and theta
oscillations showed that unlike the theta-pacing neurons,
the firing of these "pro-arousal" neurons follows theta
oscillations. However, their activity precedes short-term
increases in hippocampal oscillation power in the theta and
gamma range lasting for a few seconds. Together, these
results suggest that these pro-arousal slow-firing MSvDB
neurons may function collectively to promote hippocampal
activation.},
Doi = {10.1152/jn.00267.2011},
Key = {fds275333}
}
@article{fds275335,
Author = {O'Doherty, JE and Lebedev, MA and Ifft, PJ and Zhuang, KZ and Shokur, S and Bleuler, H and Nicolelis, MAL},
Title = {Active tactile exploration using a brain-machine-brain
interface.},
Journal = {Nature},
Volume = {479},
Number = {7372},
Pages = {228-231},
Year = {2011},
Month = {October},
ISSN = {0028-0836},
url = {http://dx.doi.org/10.1038/nature10489},
Abstract = {Brain-machine interfaces use neuronal activity recorded from
the brain to establish direct communication with external
actuators, such as prosthetic arms. It is hoped that
brain-machine interfaces can be used to restore the normal
sensorimotor functions of the limbs, but so far they have
lacked tactile sensation. Here we report the operation of a
brain-machine-brain interface (BMBI) that both controls the
exploratory reaching movements of an actuator and allows
signalling of artificial tactile feedback through
intracortical microstimulation (ICMS) of the primary
somatosensory cortex. Monkeys performed an active
exploration task in which an actuator (a computer cursor or
a virtual-reality arm) was moved using a BMBI that derived
motor commands from neuronal ensemble activity recorded in
the primary motor cortex. ICMS feedback occurred whenever
the actuator touched virtual objects. Temporal patterns of
ICMS encoded the artificial tactile properties of each
object. Neuronal recordings and ICMS epochs were temporally
multiplexed to avoid interference. Two monkeys operated this
BMBI to search for and distinguish one of three visually
identical objects, using the virtual-reality arm to identify
the unique artificial texture associated with each. These
results suggest that clinical motor neuroprostheses might
benefit from the addition of ICMS feedback to generate
artificial somatic perceptions associated with mechanical,
robotic or even virtual prostheses.},
Doi = {10.1038/nature10489},
Key = {fds275335}
}
@article{fds275355,
Author = {Dzirasa, K and McGarity, DL and Bhattacharya, A and Kumar, S and Takahashi, JS and Dunson, D and McClung, CA and Nicolelis,
MAL},
Title = {Impaired limbic gamma oscillatory synchrony during
anxiety-related behavior in a genetic mouse model of bipolar
mania.},
Journal = {Journal of Neuroscience},
Volume = {31},
Number = {17},
Pages = {6449-6456},
Year = {2011},
Month = {April},
url = {http://www.ncbi.nlm.nih.gov/pubmed/21525286},
Abstract = {Alterations in anxiety-related processing are observed
across many neuropsychiatric disorders, including bipolar
disorder. Though polymorphisms in a number of circadian
genes confer risk for this disorder, little is known about
how changes in circadian gene function disrupt brain
circuits critical for anxiety-related processing. Here we
characterize neurophysiological activity simultaneously
across five limbic brain areas (nucleus accumbens, amygdala,
prelimbic cortex, ventral hippocampus, and ventral tegmental
area) as wild-type (WT) mice and mice with a mutation in the
circadian gene, CLOCK (Clock-Δ19 mice) perform an elevated
zero maze task. In WT mice, basal limbic gamma oscillatory
synchrony observed before task performance predicted future
anxiety-related behaviors. Additionally, dynamic changes in
limbic gamma oscillatory synchrony were observed based on
the position of WT mice in the zero maze. Clock-Δ19 mice,
which displayed an increased propensity to enter the open
section of the elevated maze, showed profound deficits in
these anxiety-related circuit processes. Thus, our findings
link the anxiety-related behavioral deficits observed in
Clock-Δ19 mice with dysfunctional gamma oscillatory tuning
across limbic circuits and suggest that alterations in
limbic oscillatory circuit function induced by circadian
gene polymorphisms may contribute to the behavioral
manifestations seen in bipolar mania.},
Doi = {10.1523/JNEUROSCI.6144-10.2011},
Key = {fds275355}
}
@article{fds275332,
Author = {Nicolelis, MAL},
Title = {Mind out of body.},
Journal = {Scientific American},
Volume = {304},
Number = {2},
Pages = {80-83},
Publisher = {NATURE PUBLISHING GROUP},
Year = {2011},
Month = {February},
ISSN = {0036-8733},
url = {http://dx.doi.org/10.1038/scientificamerican0211-80},
Doi = {10.1038/scientificamerican0211-80},
Key = {fds275332}
}
@article{fds275354,
Author = {Dzirasa, K and Fuentes, R and Kumar, S and Potes, JM and Nicolelis,
MAL},
Title = {Chronic in vivo multi-circuit neurophysiological recordings
in mice.},
Journal = {J Neurosci Methods},
Volume = {195},
Number = {1},
Pages = {36-46},
Year = {2011},
Month = {January},
url = {http://www.ncbi.nlm.nih.gov/pubmed/21115042},
Abstract = {While genetically modified mice have become a widely
accepted tool for modeling the influence of gene function on
the manifestation of neurological and psychiatric
endophenotypes, only modest headway has been made in
characterizing the functional circuit changes that underlie
the disruption of complex behavioral processes in various
models. This challenge partially arises from the fact that
even simple behaviors require the coordination of many
neural circuits vastly distributed across multiple brain
areas. As such, many independent neurophysiological
alterations are likely to yield overlapping circuit
disruptions and ultimately lead to the manifestation of
similar behavioral deficits. Here we describe the expansion
of our neurophysiological recording approach in an effort to
quantify neurophysiological activity across many large scale
brain circuits simultaneously in freely behaving genetically
modified mice. Using this expanded approach we were able to
isolate up to 70 single neurons and record local field
potential (LFP) activity simultaneously across 11 brain
areas. Moreover, we found that these neurophysiological
signals remained viable up to 16 months after implantation.
Thus, our approach provides a powerful tool that will aid in
dissecting the central brain network changes that underlie
the complex behavioral deficits displayed by various
genetically modified mice.},
Doi = {10.1016/j.jneumeth.2010.11.014},
Key = {fds275354}
}
@article{fds275254,
Author = {Oliveira-Maia, AJ and Roberts, CD and Simon, SA and Nicolelis,
MAL},
Title = {Gustatory and reward brain circuits in the control of food
intake.},
Journal = {Advances and Technical Standards in Neurosurgery},
Volume = {36},
Pages = {31-59},
Year = {2011},
ISSN = {0095-4829},
url = {http://dx.doi.org/10.1007/978-3-7091-0179-7_3},
Abstract = {Gustation is a multisensory process allowing for the
selection of nutrients and the rejection of irritating
and/or toxic compounds. Since obesity is a highly prevalent
condition that is critically dependent on food intake and
energy expenditure, a deeper understanding of gustatory
processing is an important objective in biomedical research.
Recent findings have provided evidence that central
gustatory processes are distributed across several cortical
and subcortical brain areas. Furthermore, these gustatory
sensory circuits are closely related to the circuits that
process reward. Here, we present an overview of the
activation and connectivity between central gustatory and
reward areas. Moreover, and given the limitations in number
and effectiveness of treatments currently available for
overweight patients, we discuss the possibility of
modulating neuronal activity in these circuits as an
alternative in the treatment of obesity.},
Doi = {10.1007/978-3-7091-0179-7_3},
Key = {fds275254}
}
@article{fds275329,
Author = {Lopes-dos-Santos, V and Conde-Ocazionez, S and Nicolelis, MAL and Ribeiro, ST and Tort, ABL},
Title = {Neuronal assembly detection and cell membership
specification by principal component analysis.},
Journal = {Plos One},
Volume = {6},
Number = {6},
Pages = {e20996},
Year = {2011},
ISSN = {1932-6203},
url = {http://dx.doi.org/10.1371/journal.pone.0020996},
Abstract = {In 1949, Donald Hebb postulated that assemblies of
synchronously activated neurons are the elementary units of
information processing in the brain. Despite being one of
the most influential theories in neuroscience, Hebb's cell
assembly hypothesis only started to become testable in the
past two decades due to technological advances. However,
while the technology for the simultaneous recording of large
neuronal populations undergoes fast development, there is
still a paucity of analytical methods that can properly
detect and track the activity of cell assemblies. Here we
describe a principal component-based method that is able to
(1) identify all cell assemblies present in the neuronal
population investigated, (2) determine the number of neurons
involved in ensemble activity, (3) specify the precise
identity of the neurons pertaining to each cell assembly,
and (4) unravel the time course of the individual activity
of multiple assemblies. Application of the method to
multielectrode recordings of awake and behaving rats
revealed that assemblies detected in the cerebral cortex and
hippocampus typically contain overlapping neurons. The
results indicate that the PCA method presented here is able
to properly detect, track and specify neuronal assemblies,
irrespective of overlapping membership.},
Doi = {10.1371/journal.pone.0020996},
Key = {fds275329}
}
@article{fds275330,
Author = {Lebedev, MA and Tate, AJ and Hanson, TL and Li, Z and O'Doherty, JE and Winans, JA and Ifft, PJ and Zhuang, KZ and Fitzsimmons, NA and Schwarz,
DA and Fuller, AM and An, JH and Nicolelis, MAL},
Title = {Future developments in brain-machine interface
research.},
Journal = {Clinics (Sao Paulo, Brazil)},
Volume = {66 Suppl 1},
Number = {Suppl 1},
Pages = {25-32},
Year = {2011},
url = {http://www.ncbi.nlm.nih.gov/pubmed/21779720},
Abstract = {Neuroprosthetic devices based on brain-machine interface
technology hold promise for the restoration of body mobility
in patients suffering from devastating motor deficits caused
by brain injury, neurologic diseases and limb loss. During
the last decade, considerable progress has been achieved in
this multidisciplinary research, mainly in the brain-machine
interface that enacts upper-limb functionality. However, a
considerable number of problems need to be resolved before
fully functional limb neuroprostheses can be built. To move
towards developing neuroprosthetic devices for humans,
brain-machine interface research has to address a number of
issues related to improving the quality of neuronal
recordings, achieving stable, long-term performance, and
extending the brain-machine interface approach to a broad
range of motor and sensory functions. Here, we review the
future steps that are part of the strategic plan of the Duke
University Center for Neuroengineering, and its partners,
the Brazilian National Institute of Brain-Machine Interfaces
and the École Polytechnique Fédérale de Lausanne (EPFL)
Center for Neuroprosthetics, to bring this new technology to
clinical fruition.},
Doi = {10.1590/s1807-59322011001300004},
Key = {fds275330}
}
@article{fds275331,
Author = {Lebedev, MA and Nicolelis, MAL},
Title = {Toward a whole-body neuroprosthetic.},
Journal = {Prog Brain Res},
Volume = {194},
Pages = {47-60},
Year = {2011},
ISSN = {0079-6123},
url = {http://dx.doi.org/10.1016/B978-0-444-53815-4.00018-2},
Abstract = {Brain-machine interfaces (BMIs) hold promise for the
restoration of body mobility in patients suffering from
devastating motor deficits caused by brain injury,
neurological diseases, and limb loss. Considerable progress
has been achieved in BMIs that enact arm movements, and
initial work has been done on BMIs for lower limb and trunk
control. These developments put Duke University Center for
Neuroengineering in the position to develop the first BMI
for whole-body control. This whole-body BMI will incorporate
very large-scale brain recordings, advanced decoding
algorithms, artificial sensory feedback based on electrical
stimulation of somatosensory areas, virtual environment
representations, and a whole-body exoskeleton. This system
will be first tested in nonhuman primates and then
transferred to clinical trials in humans.},
Doi = {10.1016/B978-0-444-53815-4.00018-2},
Key = {fds275331}
}
@article{fds275334,
Author = {Freire, MAM and Morya, E and Faber, J and Santos, JR and Guimaraes, JS and Lemos, NAM and Sameshima, K and Pereira, A and Ribeiro, S and Nicolelis,
MAL},
Title = {Comprehensive analysis of tissue preservation and recording
quality from chronic multielectrode implants.},
Journal = {Plos One},
Volume = {6},
Number = {11},
Pages = {e27554},
Year = {2011},
ISSN = {1932-6203},
url = {http://dx.doi.org/10.1371/journal.pone.0027554},
Abstract = {Multielectrodes have been used with great success to
simultaneously record the activity of neuronal populations
in awake, behaving animals. In particular, there is great
promise in the use of this technique to allow the control of
neuroprosthetic devices by human patients. However, it is
crucial to fully characterize the tissue response to the
chronic implants in animal models ahead of the initiation of
human clinical trials. Here we evaluated the effects of
unilateral multielectrode implants on the motor cortex of
rats weekly recorded for 1-6 months using several
histological methods to assess metabolic markers,
inflammatory response, immediate-early gene (IEG)
expression, cytoskeletal integrity and apoptotic profiles.
We also investigated the correlations between each of these
features and firing rates, to estimate the impact of
post-implant time on neuronal recordings. Overall, limited
neuronal loss and glial activation were observed on the
implanted sites. Reactivity to enzymatic metabolic markers
and IEG expression were not significantly different between
implanted and non-implanted hemispheres. Multielectrode
recordings remained viable for up to 6 months after
implantation, and firing rates correlated well to the
histochemical and immunohistochemical markers. Altogether,
our results indicate that chronic tungsten multielectrode
implants do not substantially alter the histological and
functional integrity of target sites in the cerebral
cortex.},
Doi = {10.1371/journal.pone.0027554},
Key = {fds275334}
}
@article{fds275336,
Author = {Ifft, PJ and Lebedev, MA and Nicolelis, MAL},
Title = {Cortical correlates of fitts' law.},
Journal = {Frontiers in Integrative Neuroscience},
Volume = {5},
Number = {DECEMBER},
Pages = {85},
Year = {2011},
ISSN = {1662-5145},
url = {http://dx.doi.org/10.3389/fnint.2011.00085},
Abstract = {Fitts' law describes the fundamental trade-off between
movement accuracy and speed: it states that the duration of
reaching movements is a function of target size (TS) and
distance. While Fitts' law has been extensively studied in
ergonomics and has guided the design of human-computer
interfaces, there have been few studies on its neuronal
correlates. To elucidate sensorimotor cortical activity
underlying Fitts' law, we implanted two monkeys with
multielectrode arrays in the primary motor (M1) and primary
somatosensory (S1) cortices. The monkeys performed reaches
with a joystick-controlled cursor toward targets of
different size. The reaction time (RT), movement time, and
movement velocity changed with TS, and M1 and S1 activity
reflected these changes. Moreover, modifications of cortical
activity could not be explained by changes of movement
parameters alone, but required TS as an additional
parameter. Neuronal representation of TS was especially
prominent during the early RT period where it influenced the
slope of the firing rate rise preceding movement initiation.
During the movement period, cortical activity was correlated
with movement velocity. Neural decoders were applied to
simultaneously decode TS and motor parameters from cortical
modulations. We suggest that sensorimotor cortex activity
reflects the characteristics of both the movement and the
target. Classifiers that extract these parameters from
cortical ensembles could improve neuroprosthetic
control.},
Doi = {10.3389/fnint.2011.00085},
Key = {fds275336}
}
@article{fds275348,
Author = {Oliveira-Maia, AJ and Roberts, CD and Walker, QD and Luo, B and Kuhn, C and Simon, SA and Nicolelis, MAL},
Title = {Intravascular food reward.},
Journal = {Plos One},
Volume = {6},
Number = {9},
Pages = {e24992},
Publisher = {ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES
ELSEVIER},
Year = {2011},
url = {http://www.ncbi.nlm.nih.gov/pubmed/21980372},
Abstract = {Consumption of calorie-containing sugars elicits appetitive
behavioral responses and dopamine release in the ventral
striatum, even in the absence of sweet-taste transduction
machinery. However, it is unclear if such reward-related
postingestive effects reflect preabsorptive or
postabsorptive events. In support of the importance of
postabsorptive glucose detection, we found that, in rat
behavioral tests, high concentration glucose solutions
administered in the jugular vein were sufficient to
condition a side-bias. Additionally, a lower concentration
glucose solution conditioned robust behavioral responses
when administered in the hepatic-portal, but not the jugular
vein. Furthermore, enteric administration of glucose at a
concentration that is sufficient to elicit behavioral
conditioning resulted in a glycemic profile similar to that
observed after administration of the low concentration
glucose solution in the hepatic-portal, but not jugular
vein. Finally using fast-scan cyclic voltammetry we found
that, in accordance with behavioral findings, a low
concentration glucose solution caused an increase in
spontaneous dopamine release events in the nucleus accumbens
shell when administered in the hepatic-portal, but not the
jugular vein. These findings demonstrate that the
postabsorptive effects of glucose are sufficient for the
postingestive behavioral and dopaminergic reward-related
responses that result from sugar consumption. Furthermore,
glycemia levels in the hepatic-portal venous system
contribute more significantly for this effect than systemic
glycemia, arguing for the participation of an
intra-abdominal visceral sensor for glucose.},
Doi = {10.1371/journal.pone.0024992},
Key = {fds275348}
}
@article{fds275353,
Author = {Dzirasa, K and Coque, L and Sidor, MM and Kumar, S and Dancy, EA and Takahashi, JS and McClung, CA and Nicolelis, MAL},
Title = {Lithium ameliorates nucleus accumbens phase-signaling
dysfunction in a genetic mouse model of mania.},
Journal = {Journal of Neuroscience},
Volume = {30},
Number = {48},
Pages = {16314-16323},
Year = {2010},
Month = {December},
url = {http://www.ncbi.nlm.nih.gov/pubmed/21123577},
Abstract = {Polymorphisms in circadian genes such as CLOCK convey risk
for bipolar disorder. While studies have begun to elucidate
the molecular mechanism whereby disruption of Clock alters
cellular function within mesolimbic brain regions, little
remains known about how these changes alter gross neural
circuit function and generate mania-like behaviors in
Clock-Δ19 mice. Here we show that the phasic entrainment of
nucleus accumbens (NAC) low-gamma (30-55 Hz) oscillations to
delta (1-4 Hz) oscillations is negatively correlated with
the extent to which wild-type (WT) mice explore a novel
environment. Clock-Δ19 mice, which display hyperactivity in
the novel environment, exhibit profound deficits in
low-gamma and NAC single-neuron phase coupling. We also
demonstrate that NAC neurons in Clock-Δ19 mice display
complex changes in dendritic morphology and reduced GluR1
expression compared to those observed in WT littermates.
Chronic lithium treatment ameliorated several of these
neurophysiological deficits and suppressed exploratory drive
in the mutants. These results demonstrate that disruptions
of Clock gene function are sufficient to promote alterations
in NAC microcircuits, and raise the hypothesis that
dysfunctional NAC phase signaling may contribute to the
mania-like behavioral manifestations that result from
diminished circadian gene function.},
Doi = {10.1523/JNEUROSCI.4289-10.2010},
Key = {fds275353}
}
@article{fds275323,
Author = {Ribeiro, TL and Copelli, M and Caixeta, F and Belchior, H and Chialvo,
DR and Nicolelis, MAL and Ribeiro, S},
Title = {Spike avalanches exhibit universal dynamics across the
sleep-wake cycle.},
Journal = {Plos One},
Volume = {5},
Number = {11},
Pages = {e14129},
Year = {2010},
Month = {November},
ISSN = {1932-6203},
url = {http://hdl.handle.net/10161/4584 Duke open
access},
Abstract = {BACKGROUND: Scale-invariant neuronal avalanches have been
observed in cell cultures and slices as well as anesthetized
and awake brains, suggesting that the brain operates near
criticality, i.e. within a narrow margin between avalanche
propagation and extinction. In theory, criticality provides
many desirable features for the behaving brain, optimizing
computational capabilities, information transmission,
sensitivity to sensory stimuli and size of memory
repertoires. However, a thorough characterization of
neuronal avalanches in freely-behaving (FB) animals is still
missing, thus raising doubts about their relevance for brain
function. METHODOLOGY/PRINCIPAL FINDINGS: To address this
issue, we employed chronically implanted multielectrode
arrays (MEA) to record avalanches of action potentials
(spikes) from the cerebral cortex and hippocampus of 14
rats, as they spontaneously traversed the wake-sleep cycle,
explored novel objects or were subjected to anesthesia (AN).
We then modeled spike avalanches to evaluate the impact of
sparse MEA sampling on their statistics. We found that the
size distribution of spike avalanches are well fit by
lognormal distributions in FB animals, and by truncated
power laws in the AN group. FB data surrogation markedly
decreases the tail of the distribution, i.e. spike shuffling
destroys the largest avalanches. The FB data are also
characterized by multiple key features compatible with
criticality in the temporal domain, such as 1/f spectra and
long-term correlations as measured by detrended fluctuation
analysis. These signatures are very stable across waking,
slow-wave sleep and rapid-eye-movement sleep, but collapse
during anesthesia. Likewise, waiting time distributions obey
a single scaling function during all natural behavioral
states, but not during anesthesia. Results are equivalent
for neuronal ensembles recorded from visual and tactile
areas of the cerebral cortex, as well as the hippocampus.
CONCLUSIONS/SIGNIFICANCE: Altogether, the data provide a
comprehensive link between behavior and brain criticality,
revealing a unique scale-invariant regime of spike
avalanches across all major behaviors.},
Doi = {10.1371/journal.pone.0014129},
Key = {fds275323}
}
@article{fds275328,
Author = {Nicolelis, MA and Fuentes, R and Petersson, P and Thevathasan, W and Brown, P},
Title = {Spinal cord stimulation failed to relieve akinesia or
restore locomotion in Parkinson disease.},
Journal = {Neurology},
Volume = {75},
Number = {16},
Pages = {1484},
Year = {2010},
Month = {October},
ISSN = {0028-3878},
url = {http://dx.doi.org/10.1212/WNL.0b013e3181f46f10},
Doi = {10.1212/WNL.0b013e3181f46f10},
Key = {fds275328}
}
@article{fds275325,
Author = {Zhang, H and Lin, S-C and Nicolelis, MAL},
Title = {Spatiotemporal coupling between hippocampal acetylcholine
release and theta oscillations in vivo.},
Journal = {Journal of Neuroscience},
Volume = {30},
Number = {40},
Pages = {13431-13440},
Year = {2010},
Month = {October},
url = {http://www.ncbi.nlm.nih.gov/pubmed/20926669},
Abstract = {Both acetylcholine (ACh) and theta oscillations are
important for learning and memory, but the dynamic
interaction between these two processes remains unclear.
Recent advances in amperometry techniques have revealed
phasic ACh releases in vivo. However, it is unknown whether
phasic ACh release co-occurs with theta oscillations. We
investigated this issue in the CA1 region of
urethane-anesthetized male rats using amperometric and
electrophysiological recordings. We found that ACh release
was highly correlated with the appearance of both
spontaneous and induced theta oscillations. Moreover, the
maximal ACh release was observed around or slightly above
the pyramidal layer. Interestingly, such release lagged
behind theta initiation by 25-60 s. The slow ACh release
profile was matched by the slow firing rate increase of a
subset of medial-septal low-firing-rate neurons. Together,
these results establish, for the first time, the in vivo
coupling between phasic ACh release and theta oscillations
on spatiotemporal scales much finer than previously known.
These findings also suggest that phasic ACh is not required
for theta initiation and may instead operate synergistically
with theta oscillations to promote neural plasticity in the
service of learning and memory.},
Doi = {10.1523/JNEUROSCI.1144-10.2010},
Key = {fds275325}
}
@article{fds275327,
Author = {Fuentes, R and Petersson, P and Nicolelis, MAL},
Title = {Restoration of locomotive function in Parkinson's disease by
spinal cord stimulation: mechanistic approach.},
Journal = {Eur J Neurosci},
Volume = {32},
Number = {7},
Pages = {1100-1108},
Year = {2010},
Month = {October},
ISSN = {0953-816X},
url = {http://dx.doi.org/10.1111/j.1460-9568.2010.07417.x},
Abstract = {Specific motor symptoms of Parkinson's disease (PD) can be
treated effectively with direct electrical stimulation of
deep nuclei in the brain. However, this is an invasive
procedure, and the fraction of eligible patients is rather
low according to currently used criteria. Spinal cord
stimulation (SCS), a minimally invasive method, has more
recently been proposed as a therapeutic approach to
alleviate PD akinesia, in light of its proven ability to
rescue locomotion in rodent models of PD. The mechanisms
accounting for this effect are unknown but, from accumulated
experience with the use of SCS in the management of chronic
pain, it is known that the pathways most probably activated
by SCS are the superficial fibers of the dorsal columns. We
suggest that the prokinetic effect of SCS results from
direct activation of ascending pathways reaching thalamic
nuclei and the cerebral cortex. The afferent stimulation
may, in addition, activate brainstem nuclei, contributing to
the initiation of locomotion. On the basis of the striking
change in the corticostriatal oscillatory mode of neuronal
activity induced by SCS, we propose that, through activation
of lemniscal and brainstem pathways, the locomotive increase
is achieved by disruption of antikinetic low-frequency (<30
Hz) oscillatory synchronization in the corticobasal ganglia
circuits.},
Doi = {10.1111/j.1460-9568.2010.07417.x},
Key = {fds275327}
}
@article{fds364110,
Author = {Fuentes, R and Dzirasa, K and Nicolelis, MAL},
Title = {Acute Effects of Spinal Cord Stimulation in Large-Scale
Brain Circuits in a Transgenic Mouse Parkinson's
Model},
Journal = {Movement Disorders : Official Journal of the Movement
Disorder Society},
Volume = {25},
Pages = {S630-S630},
Publisher = {WILEY-LISS},
Year = {2010},
Month = {September},
Key = {fds364110}
}
@article{fds275324,
Author = {Wiest, MC and Thomson, E and Pantoja, J and Nicolelis,
MAL},
Title = {Changes in S1 neural responses during tactile discrimination
learning.},
Journal = {J Neurophysiol},
Volume = {104},
Number = {1},
Pages = {300-312},
Year = {2010},
Month = {July},
ISSN = {0022-3077},
url = {http://dx.doi.org/10.1152/jn.00194.2010},
Abstract = {In freely moving rats that are actively performing a
discrimination task, single-unit responses in primary
somatosensory cortex (S1) are strikingly different from
responses to comparable tactile stimuli in immobile rats.
For example, in the active discrimination context
prestimulus response modulations are common, responses are
longer in duration and more likely to be inhibited. To
determine whether these differences emerge as rats learned a
whisker-dependent discrimination task, we recorded
single-unit S1 activity while rats learned to discriminate
aperture-widths using their whiskers. Even before
discrimination training began, S1 responses in freely moving
rats showed many of the signatures of active responses, such
as increased duration of response and prestimulus response
modulations. As rats subsequently learned the discrimination
task, single unit responses changed: more cortical units
responded to the stimuli, neuronal sensory responses grew in
duration, and individual neurons better predicted
aperture-width. In summary, the operant behavioral context
changes S1 tactile responses even in the absence of tactile
discrimination, whereas subsequent width discrimination
learning refines the S1 representation of
aperture-width.},
Doi = {10.1152/jn.00194.2010},
Key = {fds275324}
}
@article{fds275365,
Author = {Dzirasa, K and Phillips, HW and Sotnikova, TD and Salahpour, A and Kumar, S and Gainetdinov, RR and Caron, MG and Nicolelis,
MAL},
Title = {Noradrenergic control of cortico-striato-thalamic and
mesolimbic cross-structural synchrony.},
Journal = {Journal of Neuroscience},
Volume = {30},
Number = {18},
Pages = {6387-6397},
Year = {2010},
Month = {May},
url = {http://www.ncbi.nlm.nih.gov/pubmed/20445065},
Abstract = {Although normal dopaminergic tone has been shown to be
essential for the induction of cortico-striatal and
mesolimbic theta oscillatory activity, the influence of
norepinephrine on these brain networks remains relatively
unknown. To address this question, we simultaneously
recorded local field potentials and single-neuron activity
across 10 interconnected brain areas (ventral striatum,
frontal association cortex, hippocampus, primary motor
cortex, orbital frontal cortex, prelimbic cortex, dorsal
lateral striatum, medial dorsal nucleus of thalamus,
substantia nigra pars reticularis, and ventral tegmental
area) in a combined genetically and pharmacologically
induced mouse model of hyponoradrenergia. Our results show
that norepinephrine (NE) depletion induces a novel state in
male mice characterized by a profound disruption of
coherence across multiple cortico-striatal circuits and an
increase in mesolimbic cross-structural coherence. Moreover,
this brain state is accompanied by a complex behavioral
phenotype consisting of transient hyperactivity, stereotypic
behaviors, and an acute 12-fold increase in grooming.
Notably, treatment with a norepinephrine precursors
(l-3,4-dihydroxyphenylalanine at 100 mg/kg or
l-threo-dihydroxyphenylserine at 5 mg/kg) or a selective
serotonin reuptake inhibitor (fluoxetine at 20 mg/kg)
attenuates the abnormal behaviors and selectively reverses
the circuit changes observed in NE-depleted mice. Together,
our results demonstrate that norepinephrine modulates the
dynamic tuning of coherence across cortico-striato-thalamic
circuits, and they suggest that changes in coherence across
these circuits mediate the abnormal generation of
hyperactivity and repetitive behaviors.},
Doi = {10.1523/JNEUROSCI.0764-10.2010},
Key = {fds275365}
}
@article{fds275321,
Author = {Thiagarajan, TC and Lebedev, MA and Nicolelis, MA and Plenz,
D},
Title = {Coherence potentials: loss-less, all-or-none network events
in the cortex.},
Journal = {Plos Biology},
Volume = {8},
Number = {1},
Pages = {e1000278},
Year = {2010},
Month = {January},
ISSN = {1544-9173},
url = {http://hdl.handle.net/10161/4441 Duke open
access},
Abstract = {Transient associations among neurons are thought to underlie
memory and behavior. However, little is known about how such
associations occur or how they can be identified. Here we
recorded ongoing local field potential (LFP) activity at
multiple sites within the cortex of awake monkeys and
organotypic cultures of cortex. We show that when the
composite activity of a local neuronal group exceeds a
threshold, its activity pattern, as reflected in the LFP,
occurs without distortion at other cortex sites via fast
synaptic transmission. These large-amplitude LFPs, which we
call coherence potentials, extend up to hundreds of
milliseconds and mark periods of loss-less spread of
temporal and amplitude information much like action
potentials at the single-cell level. However, coherence
potentials have an additional degree of freedom in the
diversity of their waveforms, which provides a
high-dimensional parameter for encoding information and
allows identification of particular associations. Such
nonlinear behavior is analogous to the spread of ideas and
behaviors in social networks.},
Doi = {10.1371/journal.pbio.1000278},
Key = {fds275321}
}
@article{fds275322,
Author = {Gutierrez, R and Simon, SA and Nicolelis, MAL},
Title = {Licking-induced synchrony in the taste-reward circuit
improves cue discrimination during learning.},
Journal = {Journal of Neuroscience},
Volume = {30},
Number = {1},
Pages = {287-303},
Year = {2010},
Month = {January},
url = {http://www.ncbi.nlm.nih.gov/pubmed/20053910},
Abstract = {Animals learn which foods to ingest and which to avoid.
Despite many studies, the electrophysiological correlates
underlying this behavior at the gustatory-reward circuit
level remain poorly understood. For this reason, we measured
the simultaneous electrical activity of neuronal ensembles
in the orbitofrontal cortex, insular cortex, amygdala, and
nucleus accumbens while rats licked for taste cues and
learned to perform a taste discrimination go/no-go task.
This study revealed that rhythmic licking entrains the
activity in all these brain regions, suggesting that the
animal's licking acts as an "internal clock signal" against
which single spikes can be synchronized. That is, as animals
learned a go/no-go task, there were increases in the number
of licking coherent neurons as well as synchronous spiking
between neuron pairs from different brain regions. Moreover,
a subpopulation of gustatory cue-selective neurons that
fired in synchrony with licking exhibited a greater ability
to discriminate among tastants than nonsynchronized neurons.
This effect was seen in all four recorded areas and
increased markedly after learning, particularly after the
cue was delivered and before the animals made a movement to
obtain an appetitive or aversive tastant. Overall, these
results show that, throughout a large segment of the
taste-reward circuit, appetitive and aversive associative
learning improves spike-timing precision, suggesting that
proficiency in solving a taste discrimination go/no-go task
requires licking-induced neural ensemble synchronous
activity.},
Doi = {10.1523/JNEUROSCI.0855-09.2010},
Key = {fds275322}
}
@article{fds275326,
Author = {Simões, CS and Vianney, PVR and de Moura, MM and Freire, MAM and Mello,
LE and Sameshima, K and Araújo, JF and Nicolelis, MAL and Mello, CV and Ribeiro, S},
Title = {Activation of frontal neocortical areas by vocal production
in marmosets.},
Journal = {Frontiers in Integrative Neuroscience},
Volume = {4},
Number = {SEPTEMBER 2010},
Year = {2010},
ISSN = {1662-5145},
url = {http://dx.doi.org/10.3389/fnint.2010.00123},
Abstract = {Primates often rely on vocal communication to mediate social
interactions. Although much is known about the acoustic
structure of primate vocalizations and the social context in
which they are usually uttered, our knowledge about the
neocortical control of audio-vocal interactions in primates
is still incipient, being mostly derived from lesion studies
in squirrel monkeys and macaques. To map the neocortical
areas related to vocal control in a New World primate
species, the common marmoset, we employed a method
previously used with success in other vertebrate species:
Analysis of the expression of the immediate early gene Egr-1
in freely behaving animals. The neocortical distribution of
Egr-1 immunoreactive cells in three marmosets that were
exposed to the playback of conspecific vocalizations and
vocalized spontaneously (H/V group) was compared to data
from three other marmosets that also heard the playback but
did not vocalize (H/n group). The anterior cingulate cortex,
the dorsomedial prefrontal cortex and the ventrolateral
prefrontal cortex presented a higher number of Egr-1
immunoreactive cells in the H/V group than in H/n animals.
Our results provide direct evidence that the ventrolateral
prefrontal cortex, the region that comprises Broca's area in
humans and has been associated with auditory processing of
species-specific vocalizations and orofacial control in
macaques, is engaged during vocal output in marmosets.
Altogether, our results support the notion that the network
of neocortical areas related to vocal communication in
marmosets is quite similar to that of Old world primates.
The vocal production role played by these areas and their
importance for the evolution of speech in primates are
discussed.},
Doi = {10.3389/fnint.2010.00123},
Key = {fds275326}
}
@article{fds275320,
Author = {Petermann, T and Thiagarajan, TC and Lebedev, MA and Nicolelis, MAL and Chialvo, DR and Plenz, D},
Title = {Spontaneous cortical activity in awake monkeys composed of
neuronal avalanches.},
Journal = {Proc Natl Acad Sci U S A},
Volume = {106},
Number = {37},
Pages = {15921-15926},
Year = {2009},
Month = {September},
ISSN = {0027-8424},
url = {http://dx.doi.org/10.1073/pnas.0904089106},
Abstract = {Spontaneous neuronal activity is an important property of
the cerebral cortex but its spatiotemporal organization and
dynamical framework remain poorly understood. Studies in
reduced systems--tissue cultures, acute slices, and
anesthetized rats--show that spontaneous activity forms
characteristic clusters in space and time, called neuronal
avalanches. Modeling studies suggest that networks with this
property are poised at a critical state that optimizes input
processing, information storage, and transfer, but the
relevance of avalanches for fully functional cerebral
systems has been controversial. Here we show that ongoing
cortical synchronization in awake rhesus monkeys carries the
signature of neuronal avalanches. Negative LFP deflections
(nLFPs) correlate with neuronal spiking and increase in
amplitude with increases in local population spike rate and
synchrony. These nLFPs form neuronal avalanches that are
scale-invariant in space and time and with respect to the
threshold of nLFP detection. This dimension, threshold
invariance, describes a fractal organization: smaller nLFPs
are embedded in clusters of larger ones without destroying
the spatial and temporal scale-invariance of the dynamics.
These findings suggest an organization of ongoing cortical
synchronization that is scale-invariant in its three
fundamental dimensions--time, space, and local neuronal
group size. Such scale-invariance has ontogenetic and
phylogenetic implications because it allows large increases
in network capacity without a fundamental reorganization of
the system.},
Doi = {10.1073/pnas.0904089106},
Key = {fds275320}
}
@article{fds275346,
Author = {MacDonald, CJ and Meck, WH and Simon, SA and Nicolelis,
MAL},
Title = {Taste-guided decisions differentially engage neuronal
ensembles across gustatory cortices.},
Journal = {Journal of Neuroscience},
Volume = {29},
Number = {36},
Pages = {11271-11282},
Year = {2009},
Month = {September},
url = {http://www.ncbi.nlm.nih.gov/pubmed/19741134},
Abstract = {Much remains to be understood about the differential
contributions from primary and secondary sensory cortices to
sensory-guided decision making. To address this issue we
simultaneously recorded activity from neuronal ensembles in
primary [gustatory cortex GC)] and secondary gustatory
[orbitofrontal cortex (OFC)] cortices while rats made a
taste-guided decision between two response alternatives. We
found that before animals commenced a response guided by a
tastant cue, GC ensembles contained more information than
OFC about the response alternative about to be selected.
Thereafter, while the animal's response was underway, the
response-selective information in ensembles from both
regions increased, albeit to a greater degree in OFC. In GC,
this increase depends on a representation of the taste cue
guiding the animal's response. The increase in the OFC also
depends on the taste cue guiding and other features of the
response such as its spatiomotor properties and the
behavioral context under which it is executed. Each of these
latter features is encoded by different ensembles of OFC
neurons that are recruited at specific times throughout the
response selection process. These results indicate that
during a taste-guided decision task both primary and
secondary gustatory cortices dynamically encode different
types of information.},
Doi = {10.1523/JNEUROSCI.1033-09.2009},
Key = {fds275346}
}
@article{fds275319,
Author = {Zacksenhouse, M and Nemets, S and Lebedev, MA and Nicolelis,
MAL},
Title = {Robust Satisficing Linear Regression: performance/robustness
trade-off and consistency criterion.},
Journal = {Mechanical Systems and Signal Processing},
Volume = {23},
Number = {6},
Pages = {1954-1964},
Year = {2009},
Month = {August},
ISSN = {0888-3270},
url = {http://dx.doi.org/10.1016/j.ymssp.2008.09.008},
Abstract = {Linear regression quantifies the linear relationship between
paired sets of input and output observations. The well known
least-squares regression optimizes the performance criterion
defined by the residual error, but is highly sensitive to
uncertainties or perturbations in the observations. Robust
least-squares algorithms have been developed to optimize the
worst case performance for a given limit on the level of
uncertainty, but they are applicable only when that limit is
known. Herein, we present a robust-satisficing approach that
maximizes the robustness to uncertainties in the
observations, while satisficing a critical sub-optimal level
of performance. The method emphasizes the trade-off between
performance and robustness, which are inversely correlated.
To resolve the resulting trade-off we introduce a new
criterion, which assesses the consistency between the
observations and the linear model. The proposed criterion
determines a unique robust-satisficing regression and
reveals the underlying level of uncertainty in the
observations with only weak assumptions. These algorithms
are demonstrated for the challenging application of linear
regression to neural decoding for brain-machine interfaces.
The model-consistent robust-satisfying regression provides
superior performance for new observations under both similar
and different conditions.},
Doi = {10.1016/j.ymssp.2008.09.008},
Key = {fds275319}
}
@article{fds275347,
Author = {Alexander, GM and Rogan, SC and Abbas, AI and Armbruster, BN and Pei, Y and Allen, JA and Nonneman, RJ and Hartmann, J and Moy, SS and Nicolelis,
MA and McNamara, JO and Roth, BL},
Title = {Remote control of neuronal activity in transgenic mice
expressing evolved G protein-coupled receptors.},
Journal = {Neuron},
Volume = {63},
Number = {1},
Pages = {27-39},
Year = {2009},
Month = {July},
url = {http://www.ncbi.nlm.nih.gov/pubmed/19607790},
Abstract = {Examining the behavioral consequences of selective CNS
neuronal activation is a powerful tool for elucidating
mammalian brain function in health and disease. Newly
developed genetic, pharmacological, and optical tools allow
activation of neurons with exquisite spatiotemporal
resolution; however, the inaccessibility to light of widely
distributed neuronal populations and the invasiveness
required for activation by light or infused ligands limit
the utility of these methods. To overcome these barriers, we
created transgenic mice expressing an evolved G
protein-coupled receptor (hM3Dq) selectively activated by
the pharmacologically inert, orally bioavailable drug
clozapine-N-oxide (CNO). Here, we expressed hM3Dq in
forebrain principal neurons. Local field potential and
single-neuron recordings revealed that peripheral
administration of CNO activated hippocampal neurons
selectively in hM3Dq-expressing mice. Behavioral correlates
of neuronal activation included increased locomotion,
stereotypy, and limbic seizures. These results demonstrate a
powerful chemical-genetic tool for remotely controlling the
activity of discrete populations of neurons in
vivo.},
Doi = {10.1016/j.neuron.2009.06.014},
Key = {fds275347}
}
@article{fds275352,
Author = {Li, Z and O'Doherty, JE and Hanson, TL and Lebedev, MA and Henriquez,
CS and Nicolelis, MAL},
Title = {Unscented Kalman filter for brain-machine
interfaces.},
Journal = {Plos One},
Volume = {4},
Number = {7},
Pages = {e6243},
Year = {2009},
Month = {July},
url = {http://www.ncbi.nlm.nih.gov/pubmed/19603074},
Abstract = {Brain machine interfaces (BMIs) are devices that convert
neural signals into commands to directly control artificial
actuators, such as limb prostheses. Previous real-time
methods applied to decoding behavioral commands from the
activity of populations of neurons have generally relied
upon linear models of neural tuning and were limited in the
way they used the abundant statistical information contained
in the movement profiles of motor tasks. Here, we propose an
n-th order unscented Kalman filter which implements two key
features: (1) use of a non-linear (quadratic) model of
neural tuning which describes neural activity significantly
better than commonly-used linear tuning models, and (2)
augmentation of the movement state variables with a history
of n-1 recent states, which improves prediction of the
desired command even before incorporating neural activity
information and allows the tuning model to capture
relationships between neural activity and movement at
multiple time offsets simultaneously. This new filter was
tested in BMI experiments in which rhesus monkeys used their
cortical activity, recorded through chronically implanted
multielectrode arrays, to directly control computer cursors.
The 10th order unscented Kalman filter outperformed the
standard Kalman filter and the Wiener filter in both
off-line reconstruction of movement trajectories and
real-time, closed-loop BMI operation.},
Doi = {10.1371/journal.pone.0006243},
Key = {fds275352}
}
@article{fds275317,
Author = {Nicolelis, MAL and Lebedev, MA},
Title = {Principles of neural ensemble physiology underlying the
operation of brain-machine interfaces.},
Journal = {Nat Rev Neurosci},
Volume = {10},
Number = {7},
Pages = {530-540},
Year = {2009},
Month = {July},
ISSN = {1471-003X},
url = {http://dx.doi.org/10.1038/nrn2653},
Abstract = {Research on brain-machine interfaces has been ongoing for at
least a decade. During this period, simultaneous recordings
of the extracellular electrical activity of hundreds of
individual neurons have been used for direct, real-time
control of various artificial devices. Brain-machine
interfaces have also added greatly to our knowledge of the
fundamental physiological principles governing the operation
of large neural ensembles. Further understanding of these
principles is likely to have a key role in the future
development of neuroprosthetics for restoring mobility in
severely paralysed patients.},
Doi = {10.1038/nrn2653},
Key = {fds275317}
}
@article{fds275364,
Author = {Dzirasa, K and Ramsey, AJ and Takahashi, DY and Stapleton, J and Potes,
JM and Williams, JK and Gainetdinov, RR and Sameshima, K and Caron, MG and Nicolelis, MAL},
Title = {Hyperdopaminergia and NMDA receptor hypofunction disrupt
neural phase signaling.},
Journal = {Journal of Neuroscience},
Volume = {29},
Number = {25},
Pages = {8215-8224},
Year = {2009},
Month = {June},
url = {http://www.ncbi.nlm.nih.gov/pubmed/19553461},
Abstract = {Neural phase signaling has gained attention as a putative
coding mechanism through which the brain binds the activity
of neurons across distributed brain areas to generate
thoughts, percepts, and behaviors. Neural phase signaling
has been shown to play a role in various cognitive
processes, and it has been suggested that altered phase
signaling may play a role in mediating the cognitive
deficits observed across neuropsychiatric illness. Here, we
investigated neural phase signaling in two mouse models of
cognitive dysfunction: mice with genetically induced
hyperdopaminergia [dopamine transporter knock-out (DAT-KO)
mice] and mice with genetically induced NMDA receptor
hypofunction [NMDA receptor subunit-1 knockdown (NR1-KD)
mice]. Cognitive function in these mice was assessed using a
radial-arm maze task, and local field potentials were
recorded from dorsal hippocampus and prefrontal cortex as
DAT-KO mice, NR1-KD mice, and their littermate controls
engaged in behavioral exploration. Our results demonstrate
that both DAT-KO and NR1-KD mice display deficits in spatial
cognitive performance. Moreover, we show that persistent
hyperdopaminergia alters interstructural phase signaling,
whereas NMDA receptor hypofunction alters interstructural
and intrastructural phase signaling. These results
demonstrate that dopamine and NMDA receptor dependent
glutamate signaling play a critical role in coordinating
neural phase signaling, and encourage further studies to
investigate the role that deficits in phase signaling play
in mediating cognitive dysfunction.},
Doi = {10.1523/JNEUROSCI.1773-09.2009},
Key = {fds275364}
}
@article{fds275318,
Author = {Peikon, ID and Fitzsimmons, NA and Lebedev, MA and Nicolelis,
MAL},
Title = {Three-dimensional, automated, real-time video system for
tracking limb motion in brain-machine interface
studies.},
Journal = {J Neurosci Methods},
Volume = {180},
Number = {2},
Pages = {224-233},
Year = {2009},
Month = {June},
ISSN = {0165-0270},
url = {http://dx.doi.org/10.1016/j.jneumeth.2009.03.010},
Abstract = {Collection and analysis of limb kinematic data are essential
components of the study of biological motion, including
research into biomechanics, kinesiology, neurophysiology and
brain-machine interfaces (BMIs). In particular, BMI research
requires advanced, real-time systems capable of sampling
limb kinematics with minimal contact to the subject's body.
To answer this demand, we have developed an automated video
tracking system for real-time tracking of multiple body
parts in freely behaving primates. The system employs
high-contrast markers painted on the animal's joints to
continuously track the three-dimensional positions of their
limbs during activity. Two-dimensional coordinates captured
by each video camera are combined and converted to
three-dimensional coordinates using a quadratic fitting
algorithm. Real-time operation of the system is accomplished
using direct memory access (DMA). The system tracks the
markers at a rate of 52 frames per second (fps) in real-time
and up to 100fps if video recordings are captured to be
later analyzed off-line. The system has been tested in
several BMI primate experiments, in which limb position was
sampled simultaneously with chronic recordings of the
extracellular activity of hundreds of cortical cells. During
these recordings, multiple computational models were
employed to extract a series of kinematic parameters from
neuronal ensemble activity in real-time. The system operated
reliably under these experimental conditions and was able to
compensate for marker occlusions that occurred during
natural movements. We propose that this system could also be
extended to applications that include other classes of
biological motion.},
Doi = {10.1016/j.jneumeth.2009.03.010},
Key = {fds275318}
}
@article{fds275316,
Author = {Zhang, H and Lin, S-C and Nicolelis, MAL},
Title = {Acquiring local field potential information from
amperometric neurochemical recordings.},
Journal = {J Neurosci Methods},
Volume = {179},
Number = {2},
Pages = {191-200},
Year = {2009},
Month = {May},
url = {http://www.ncbi.nlm.nih.gov/pubmed/19428527},
Abstract = {Simultaneous acquisition of in vivo electrophysiological and
neurochemical information is essential for understanding how
endogenous neurochemicals modulate the dynamics of brain
activity. However, up to now such a task has rarely been
accomplished due to the major technical challenge of
operating two independent recording systems simultaneously
in real-time. Here we propose a simpler solution for
achieving this goal by using only a standard electrochemical
technique--amperometry. To demonstrate its feasibility, we
compared amperometric signals with simultaneously recorded
local field potential (LFP) signals. We found that the high
frequency component (HFC) of the amperometric signals did
not reflect neurochemical fluctuations, but instead it
resembled LFPs in several aspects, including: (1) coherent
spectral fluctuations; (2) clear characterization of
different brain states; (3) identical hippocampal theta
depth profile. As such, our findings provide the first
demonstration that both LFP and local neurochemical
information can be simultaneously acquired from
electrochemical sensors alone.},
Doi = {10.1016/j.jneumeth.2009.01.023},
Key = {fds275316}
}
@article{fds275315,
Author = {Rizk, M and Bossetti, CA and Jochum, TA and Callender, SH and Nicolelis,
MAL and Turner, DA and Wolf, PD},
Title = {A fully implantable 96-channel neural data acquisition
system.},
Journal = {J Neural Eng},
Volume = {6},
Number = {2},
Pages = {026002},
Year = {2009},
Month = {April},
url = {http://www.ncbi.nlm.nih.gov/pubmed/19255459},
Abstract = {A fully implantable neural data acquisition system is a key
component of a clinically viable brain-machine interface.
This type of system must communicate with the outside world
and obtain power without the use of wires that cross through
the skin. We present a 96-channel fully implantable neural
data acquisition system. This system performs spike
detection and extraction within the body and wirelessly
transmits data to an external unit. Power is supplied
wirelessly through the use of inductively coupled coils. The
system was implanted acutely in sheep and successfully
recorded, processed and transmitted neural data.
Bidirectional communication between the implanted system and
an external unit was successful over a range of 2 m. The
system is also shown to integrate well into a brain-machine
interface. This demonstration of a high channel-count fully
implanted neural data acquisition system is a critical step
in the development of a clinically viable brain-machine
interface.},
Doi = {10.1088/1741-2560/6/2/026002},
Key = {fds275315}
}
@article{fds275362,
Author = {Fuentes, R and Petersson, P and Siesser, WB and Caron, MG and Nicolelis,
MAL},
Title = {Spinal cord stimulation restores locomotion in animal models
of Parkinson's disease.},
Journal = {Science},
Volume = {323},
Number = {5921},
Pages = {1578-1582},
Year = {2009},
Month = {March},
url = {http://www.ncbi.nlm.nih.gov/pubmed/19299613},
Abstract = {Dopamine replacement therapy is useful for treating motor
symptoms in the early phase of Parkinson's disease, but it
is less effective in the long term. Electrical deep-brain
stimulation is a valuable complement to pharmacological
treatment but involves a highly invasive surgical procedure.
We found that epidural electrical stimulation of the dorsal
columns in the spinal cord restores locomotion in both acute
pharmacologically induced dopamine-depleted mice and in
chronic 6-hydroxydopamine-lesioned rats. The functional
recovery was paralleled by a disruption of aberrant
low-frequency synchronous corticostriatal oscillations,
leading to the emergence of neuronal activity patterns that
resemble the state normally preceding spontaneous initiation
of locomotion. We propose that dorsal column stimulation
might become an efficient and less invasive alternative for
treatment of Parkinson's disease in the future.},
Doi = {10.1126/science.1164901},
Key = {fds275362}
}
@article{fds275314,
Author = {Oliveira-Maia, AJ and Stapleton-Kotloski, JR and Lyall, V and Phan,
T-HT and Mummalaneni, S and Melone, P and Desimone, JA and Nicolelis,
MAL and Simon, SA},
Title = {Nicotine activates TRPM5-dependent and independent taste
pathways.},
Journal = {Proc Natl Acad Sci U S A},
Volume = {106},
Number = {5},
Pages = {1596-1601},
Year = {2009},
Month = {February},
ISSN = {0027-8424},
url = {http://dx.doi.org/10.1073/pnas.0810184106},
Abstract = {The orosensory responses elicited by nicotine are relevant
for the development and maintenance of addiction to tobacco
products. However, although nicotine is described as bitter
tasting, the molecular and neural substrates encoding the
taste of nicotine are unclear. Here, rats and mice were used
to determine whether nicotine activates peripheral and
central taste pathways via TRPM5-dependent mechanisms, which
are essential for responses to other bitter tastants such as
quinine, and/or via nicotinic acetylcholine receptors
(nAChRs). When compared with wild-type mice, Trpm5(-/-) mice
had reduced, but not abolished, chorda tympani (CT)
responses to nicotine. In both genotypes, lingual
application of mecamylamine, a nAChR-antagonist, inhibited
CT nerve responses to nicotine and reduced behavioral
responses of aversion to this stimulus. In accordance with
these findings, rats were shown to discriminate between
nicotine and quinine presented at intensity-paired
concentrations. Moreover, rat gustatory cortex (GC) neural
ensemble activity could also discriminate between these two
bitter tastants. Mecamylamine reduced both behavioral and GC
neural discrimination between nicotine and quinine. In
summary, nicotine elicits taste responses through peripheral
TRPM5-dependent pathways, common to other bitter tastants,
and nAChR-dependent and TRPM5-independent pathways, thus
creating a unique sensory representation that contributes to
the sensory experience of tobacco products.},
Doi = {10.1073/pnas.0810184106},
Key = {fds275314}
}
@article{fds275263,
Author = {Ribeiro, S and Nicolelis, M},
Title = {Sleep and sleep states: Network reactivation},
Pages = {937-944},
Publisher = {Elsevier},
Year = {2009},
Month = {January},
url = {http://dx.doi.org/10.1016/B978-008045046-9.00058-9},
Abstract = {Network reactivation is a key neural property for the
generation of innate and learned behavior. The activation of
recurrent anatomical loops underlies the different rhythms
produced by the brain, characterizing the distinct global
states that comprise waking and sleep. Memories encoded by
coordinated neuronal ensembles reverberate across all states
with intensity inversely proportional to sensory and motor
interference. Network reactivation at the level of neuronal
populations increases during sleep and is proportional to
learning. Reactivation can be traced to molecular
mechanisms, such as plasticity-related gene expression
during sleep. Waking thought, dreams, and nondreaming sleep
mentation reflect memory reactivation under different
regimes of neural processing. © 2009 Elsevier Ltd All
rights reserved.},
Doi = {10.1016/B978-008045046-9.00058-9},
Key = {fds275263}
}
@article{fds275257,
Author = {Fitzsimmons, NA and Lebedev, MA and Peikon, ID and Nicolelis,
MAL},
Title = {Extracting kinematic parameters for monkey bipedal walking
from cortical neuronal ensemble activity.},
Journal = {Frontiers in Integrative Neuroscience},
Volume = {3},
Pages = {3},
Year = {2009},
url = {http://dx.doi.org/10.3389/neuro.07.003.2009},
Abstract = {The ability to walk may be critically impacted as the result
of neurological injury or disease. While recent advances in
brain-machine interfaces (BMIs) have demonstrated the
feasibility of upper-limb neuroprostheses, BMIs have not
been evaluated as a means to restore walking. Here, we
demonstrate that chronic recordings from ensembles of
cortical neurons can be used to predict the kinematics of
bipedal walking in rhesus macaques - both offline and in
real time. Linear decoders extracted 3D coordinates of leg
joints and leg muscle electromyograms from the activity of
hundreds of cortical neurons. As more complex patterns of
walking were produced by varying the gait speed and
direction, larger neuronal populations were needed to
accurately extract walking patterns. Extraction was further
improved using a switching decoder which designated a
submodel for each walking paradigm. We propose that BMIs may
one day allow severely paralyzed patients to walk
again.},
Doi = {10.3389/neuro.07.003.2009},
Key = {fds275257}
}
@article{fds275258,
Author = {O'Doherty, JE and Lebedev, MA and Hanson, TL and Fitzsimmons, NA and Nicolelis, MAL},
Title = {A brain-machine interface instructed by direct intracortical
microstimulation.},
Journal = {Frontiers in Integrative Neuroscience},
Volume = {3},
Pages = {20},
Year = {2009},
url = {http://dx.doi.org/10.3389/neuro.07.020.2009},
Abstract = {Brain-machine interfaces (BMIs) establish direct
communication between the brain and artificial actuators. As
such, they hold considerable promise for restoring mobility
and communication in patients suffering from severe body
paralysis. To achieve this end, future BMIs must also
provide a means for delivering sensory signals from the
actuators back to the brain. Prosthetic sensation is needed
so that neuroprostheses can be better perceived and
controlled. Here we show that a direct intracortical input
can be added to a BMI to instruct rhesus monkeys in choosing
the direction of reaching movements generated by the BMI.
Somatosensory instructions were provided to two monkeys
operating the BMI using either: (a) vibrotactile stimulation
of the monkey's hands or (b) multi-channel intracortical
microstimulation (ICMS) delivered to the primary
somatosensory cortex (S1) in one monkey and posterior
parietal cortex (PP) in the other. Stimulus delivery was
contingent on the position of the computer cursor: the
monkey placed it in the center of the screen to receive
machine-brain recursive input. After 2 weeks of training,
the same level of proficiency in utilizing somatosensory
information was achieved with ICMS of S1 as with the
stimulus delivered to the hand skin. ICMS of PP was not
effective. These results indicate that direct,
bi-directional communication between the brain and
neuroprosthetic devices can be achieved through the
combination of chronic multi-electrode recording and
microstimulation of S1. We propose that in the future,
bidirectional BMIs incorporating ICMS may become an
effective paradigm for sensorizing neuroprosthetic
devices.},
Doi = {10.3389/neuro.07.020.2009},
Key = {fds275258}
}
@article{fds275363,
Author = {Dzirasa, K and Santos, LM and Ribeiro, S and Stapleton, J and Gainetdinov, RR and Caron, MG and Nicolelis, MAL},
Title = {Persistent hyperdopaminergia decreases the peak frequency of
hippocampal theta oscillations during quiet waking and REM
sleep.},
Journal = {Plos One},
Volume = {4},
Number = {4},
Pages = {e5238},
Year = {2009},
url = {http://www.ncbi.nlm.nih.gov/pubmed/19381303},
Abstract = {Long-term changes in dopaminergic signaling are thought to
underlie the pathophysiology of a number of psychiatric
disorders. Several conditions are associated with cognitive
deficits such as disturbances in attention processes and
learning and memory, suggesting that persistent changes in
dopaminergic signaling may alter neural mechanisms
underlying these processes. Dopamine transporter knockout
(DAT-KO) mice exhibit a persistent five-fold increase in
extracellular dopamine levels. Here, we demonstrate that
DAT-KO mice display lower hippocampal theta oscillation
frequencies during baseline periods of waking and rapid-eye
movement sleep. These altered theta oscillations are not
reversed via treatment with the antidopaminergic agent
haloperidol. Thus, we propose that persistent
hyperdopaminergia, together with secondary alterations in
other neuromodulatory systems, results in lower frequency
activity in neural systems responsible for various cognitive
processes.},
Doi = {10.1371/journal.pone.0005238},
Key = {fds275363}
}
@article{fds275245,
Author = {Ribeiro, S and Simões, C and Nicolelis, M},
Title = {Genes, sleep and dreams},
Pages = {413-429},
Publisher = {Springer Netherlands},
Year = {2008},
Month = {December},
url = {http://dx.doi.org/10.1007/978-1-4020-8352-5_17},
Abstract = {This Chapter considers the continuing debate regarding the
mechanisms that underlie the cognitive role of sleep. One
theory proposes that the triggering of generalized synaptic
downscaling occurs so as to restore homeostatic balance and
enable further waking potentiation. The alternative, favored
by the present authors, proposes that sleep harbors
decreased and increased plasticity in separate circuits.
Further work is required to resolve this debate. © 2008
Springer Science+Business Media B.V.},
Doi = {10.1007/978-1-4020-8352-5_17},
Key = {fds275245}
}
@article{fds364112,
Author = {Oliveira-Maia, AJ and Phan, T-HT and Melone, PD and Mummalaneni, S and Nicolelis, MAL and Simon, SA and DeSimone, JA and Lyall,
V},
Title = {Nicotinic Acetylcholine Receptors (NACHRS): Novel Bitter
Taste Receptors for Nicotine},
Journal = {Chemical Senses},
Volume = {33},
Number = {8},
Pages = {S113-S113},
Publisher = {OXFORD UNIV PRESS},
Year = {2008},
Month = {October},
Key = {fds364112}
}
@article{fds275313,
Author = {Lin, S-C and Nicolelis, MAL},
Title = {Neuronal ensemble bursting in the basal forebrain encodes
salience irrespective of valence.},
Journal = {Neuron},
Volume = {59},
Number = {1},
Pages = {138-149},
Year = {2008},
Month = {July},
ISSN = {0896-6273},
url = {http://dx.doi.org/10.1016/j.neuron.2008.04.031},
Abstract = {Both reward- and punishment-related stimuli are
motivationally salient and attract the attention of animals.
However, it remains unclear how motivational salience is
processed in the brain. Here, we show that both reward- and
punishment-predicting stimuli elicited robust bursting of
many noncholinergic basal forebrain (BF) neurons in behaving
rats. The same BF neurons also responded with similar
bursting to primary reinforcement of both valences.
Reinforcement responses were modulated by expectation, with
surprising reinforcement eliciting stronger BF bursting. We
further demonstrate that BF burst firing predicted
successful detection of near-threshold stimuli. Together,
our results point to the existence of a salience-encoding
system independent of stimulus valence. We propose that the
encoding of motivational salience by ensemble bursting of
noncholinergic BF neurons may improve behavioral performance
by affecting the activity of widespread cortical circuits
and therefore represents a novel candidate mechanism for
top-down attention.},
Doi = {10.1016/j.neuron.2008.04.031},
Key = {fds275313}
}
@article{fds275361,
Author = {de Araujo, IE and Oliveira-Maia, AJ and Sotnikova, TD and Gainetdinov, RR and Caron, MG and Nicolelis, MAL and Simon,
SA},
Title = {Food Reward in the Absence of Taste Receptor Signaling
(DOI:10.1016/j.neuron.2008.01.032)},
Journal = {Neuron},
Volume = {58},
Number = {2},
Pages = {295},
Year = {2008},
Month = {April},
ISSN = {0896-6273},
url = {http://dx.doi.org/10.1016/j.neuron.2008.04.003},
Doi = {10.1016/j.neuron.2008.04.003},
Key = {fds275361}
}
@article{fds275360,
Author = {de Araujo, IE and Oliveira-Maia, AJ and Sotnikova, TD and Gainetdinov, RR and Caron, MG and Nicolelis, MAL and Simon,
SA},
Title = {Food reward in the absence of taste receptor
signaling.},
Journal = {Neuron},
Volume = {57},
Number = {6},
Pages = {930-941},
Year = {2008},
Month = {March},
url = {http://www.ncbi.nlm.nih.gov/pubmed/18367093},
Abstract = {Food palatability and hedonic value play central roles in
nutrient intake. However, postingestive effects can
influence food preferences independently of palatability,
although the neurobiological bases of such mechanisms remain
poorly understood. Of central interest is whether the same
brain reward circuitry that is responsive to palatable
rewards also encodes metabolic value independently of taste
signaling. Here we show that trpm5-/- mice, which lack the
cellular machinery required for sweet taste transduction,
can develop a robust preference for sucrose solutions based
solely on caloric content. Sucrose intake induced dopamine
release in the ventral striatum of these sweet-blind mice, a
pattern usually associated with receipt of palatable
rewards. Furthermore, single neurons in this same ventral
striatal region showed increased sensitivity to caloric
intake even in the absence of gustatory inputs. Our findings
suggest that calorie-rich nutrients can directly influence
brain reward circuits that control food intake independently
of palatability or functional taste transduction.},
Doi = {10.1016/j.neuron.2008.01.032},
Key = {fds275360}
}
@article{fds275312,
Author = {Da Silva and LIL and Haddad, F and Nicolelis, MAL},
Title = {Brazil's option for science education.},
Journal = {Scientific American},
Volume = {298},
Number = {2},
Pages = {25},
Year = {2008},
Month = {February},
ISSN = {0036-8733},
Key = {fds275312}
}
@article{fds275261,
Author = {Wiest, MC and Thomson, E and Nicolelis, MAL},
Title = {Twenty-Five Years of Multielectrode Recordings in the
Somatosensory System: It is All about Dynamics},
Volume = {6},
Pages = {315-330},
Publisher = {Elsevier},
Year = {2008},
Month = {January},
url = {http://dx.doi.org/10.1016/B978-012370880-9.00360-1},
Abstract = {Chronic multielectrode recording methods introduced 25 years
ago have opened up the opportunity to simultaneously sample
the activity of neurons at multiple levels of the
somatosensory system while rats engage in active tactile
behaviors. This chapter focuses on results gleaned from
recordings in the rat whisker system. The earliest
multielectrode investigations revealed that the peak of
neural activity evoked by single-whisker stimuli drifts
widely over the cortical and thalamic somatotopic whisker
maps. This property could provide a mechanism for
recognizing spatiotemporal patterns of whisker stimulation.
These studies also showed that information about tactile
stimulus identity is carried by the relative latencies of
evoked spikes in different simultaneously recorded neurons.
Subsequent experiments also revealed highly synchronized
firing in neurons from brainstem to cortex, and immediate
receptive field reorganization in thalamus induced by
partial deafferentation or reversible inactivation of
primary somatosensory cortex (S1). Even the two hemispheres
of S1, long viewed as independent modules for processing
exclusively contralateral stimuli, were found to interact on
millisecond timescales in anesthetized and waking rats. This
later finding suggested that the brain combines bilateral
whisker afferents to discriminate bilateral whisker stimuli
- such as the widths of tunnel openings in the dark - an
idea that was confirmed by the development of bilateral
tactile discrimination tasks. Multielectrode recordings
during tactile discrimination revealed qualitatively
distinct response modes in S1 as compared to responses to
passive whisker stimulation, including task-related firing
rate modulations that begin well before whisker stimulation.
These data have pushed our conception of somatosensory
representation - even at the earliest thalamic and cortical
processing stages - away from the static classical
one-barrel/one-whisker picture, toward that of a highly
plastic multilevel structure whose functional architecture
quickly adjusts to meet the demands of the present
situation. © 2008 Elsevier Inc. All rights
reserved.},
Doi = {10.1016/B978-012370880-9.00360-1},
Key = {fds275261}
}
@article{fds275310,
Author = {Da Silva and LIL and Haddad, F and Nicolelis, MAL},
Title = {Brazil's option for science education},
Journal = {Scientific American},
Volume = {298},
Number = {2},
Pages = {33},
Publisher = {SCI AMERICAN INC},
Year = {2008},
Month = {January},
ISSN = {0036-8733},
url = {http://dx.doi.org/10.1038/scientificamerican0208-33},
Doi = {10.1038/scientificamerican0208-33},
Key = {fds275310}
}
@article{fds275311,
Author = {Lebedev, MA and O'Doherty, JE and Nicolelis, MAL},
Title = {Decoding of temporal intervals from cortical ensemble
activity.},
Journal = {Journal of Neurophysiology},
Volume = {99},
Number = {1},
Pages = {166-186},
Year = {2008},
Month = {January},
ISSN = {0022-3077},
url = {http://dx.doi.org/10.1152/jn.00734.2007},
Abstract = {Neurophysiological, neuroimaging, and lesion studies point
to a highly distributed processing of temporal information
by cortico-basal ganglia-thalamic networks. However, there
are virtually no experimental data on the encoding of
behavioral time by simultaneously recorded cortical
ensembles. We predicted temporal intervals from the activity
of hundreds of neurons recorded in motor and premotor cortex
as rhesus monkeys performed self-timed hand movements.
During the delay periods, when animals had to estimate
temporal intervals and prepare hand movements, neuronal
ensemble activity encoded both the time that elapsed from
the previous hand movement and the time until the onset of
the next. The neurons that were most informative of these
temporal intervals increased or decreased their rates
throughout the delay until reaching a threshold value, at
which point a movement was initiated. Variability in the
self-timed delays was explainable by the variability of
neuronal rates, but not of the threshold. In addition to
predicting temporal intervals, the same neuronal ensemble
activity was informative for generating predictions that
dissociated the delay periods of the task from the movement
periods. Left hemispheric areas were the best source of
predictions in one bilaterally implanted monkey overtrained
to perform the task with the right hand. However, after that
monkey learned to perform the task with the left hand, its
left hemisphere continued and the right hemisphere started
contributing to the prediction. We suggest that decoding of
temporal intervals from bilaterally recorded cortical
ensembles could improve the performance of neural prostheses
for restoration of motor function.},
Doi = {10.1152/jn.00734.2007},
Key = {fds275311}
}
@article{fds275308,
Author = {Soares, ES and Stapleton, JR and Rodriguez, A and Fitzsimmons, N and Oliveira, L and Nicolelis, MAL and Simon, SA},
Title = {Behavioral and neural responses to gustatory stimuli
delivered non-contingently through intra-oral
cannulas.},
Journal = {Physiology & Behavior},
Volume = {92},
Number = {4},
Pages = {629-642},
Year = {2007},
Month = {November},
ISSN = {0031-9384},
url = {http://www.ncbi.nlm.nih.gov/pubmed/17588623},
Abstract = {The act of eating requires a decision by an animal to place
food in its mouth. The reasons to eat are varied and include
hunger as well as the food's expected reward value. Previous
studies of tastant processing in the rat primary gustatory
cortex (GC) have used either anesthetized or awake behaving
preparations that yield somewhat different results. Here we
have developed a new preparation in which we explore the
influences of intra-oral and non-contingent tastant delivery
on rats' behavior and on their GC neural responses. We
recorded single-unit activity in the rat GC during two
sequences of tastant deliveries, PRE and POST, which were
separated by a waiting period. Six tastants ranging in
hedonic value from sucrose to quinine were delivered in the
first two protocols called 4TW and L-S. In the third one,
the App L-S protocol, only hedonically positive tastants
were used. In the 4TW protocol, tastants were delivered in
blocks whereas in the two L-S protocols tastants were
randomly interleaved. In the 4TW and L-S protocols the
probability of ingesting tastants in the PRE sequence
decreased exponentially with the trial number. Moreover, in
both protocols this decrease was greater in the POST than in
the PRE sequence likely because the subjects learned that
unpleasant tastants were to be delivered. In the App L-S
protocol the decrease in ingestion was markedly slower than
in the other protocols, thus supporting the hypothesis that
the decrease in appetitive behavior arises from the
non-contingent intra-oral delivery of hedonically negative
tastants like quinine. Although neuronal responses in the
three protocols displayed similar variability levels,
significant differences existed between the protocols in the
way the variability was partitioned between chemosensory and
non-chemosensory neurons. While in the 4TW and L-S protocols
the former population displayed more changes than the
latter, in the App L-S protocol variability was
homogeneously distributed between the two populations. We
posit that these tuning changes arise, at least in part,
from compounds released upon ingestion, and also from
differences in areas of the oral cavity that are bathed as
the animals ingest or reject the tastants.},
Doi = {10.1016/j.physbeh.2007.05.038},
Key = {fds275308}
}
@article{fds275307,
Author = {Pereira, A and Ribeiro, S and Wiest, M and Moore, LC and Pantoja, J and Lin, S-C and Nicolelis, MAL},
Title = {Processing of tactile information by the
hippocampus.},
Journal = {Proc Natl Acad Sci U S A},
Volume = {104},
Number = {46},
Pages = {18286-18291},
Year = {2007},
Month = {November},
ISSN = {0027-8424},
url = {http://dx.doi.org/10.1073/pnas.0708611104},
Abstract = {The ability to detect unusual events occurring in the
environment is essential for survival. Several studies have
pointed to the hippocampus as a key brain structure in
novelty detection, a claim substantiated by its wide access
to sensory information through the entorhinal cortex and
also distinct aspects of its intrinsic circuitry. Novelty
detection is implemented by an associative match-mismatch
algorithm involving the CA1 and CA3 hippocampal subfields
that compares the stream of sensory inputs received by CA1
to the stored representation of spatiotemporal sequences in
CA3. In some rodents, including the rat, the highly
sensitive facial whiskers are responsible for providing
accurate tactile information about nearby objects.
Surprisingly, however, not much is known about how inputs
from the whiskers reach CA1 and how they are processed
therein. Using concurrent multielectrode neuronal recordings
and chemical inactivation in behaving rats, we show that
trigeminal inputs from the whiskers reach the CA1 region
through thalamic and cortical relays associated with
discriminative touch. Ensembles of hippocampal neurons also
carry precise information about stimulus identity when
recorded during performance in an aperture-discrimination
task using the whiskers. We also found broad similarities
between tactile responses of trigeminal stations and the
hippocampus during different vigilance states (wake and
sleep). Taken together, our results show that tactile
information associated with fine whisker discrimination is
readily available to the hippocampus for dynamic updating of
spatial maps.},
Doi = {10.1073/pnas.0708611104},
Key = {fds275307}
}
@article{fds351214,
Author = {Ribeiro, S and Shi, X and Engelhard, M and Zhou, Y and Zhang, H and Gervasoni, D and Lin, S-C and Wada, K and Lemos, NAM and Nicolelis,
MAL},
Title = {Novel experience induces persistent sleep-dependent
plasticity in the cortex but not in the hippocampus.},
Journal = {Frontiers in Neuroscience},
Volume = {1},
Number = {1},
Pages = {43-55},
Year = {2007},
Month = {November},
url = {http://dx.doi.org/10.3389/neuro.01.1.1.003.2007},
Abstract = {Episodic and spatial memories engage the hippocampus during
acquisition but migrate to the cerebral cortex over time. We
have recently proposed that the interplay between slow-wave
(SWS) and rapid eye movement (REM) sleep propagates recent
synaptic changes from the hippocampus to the cortex. To test
this theory, we jointly assessed extracellular neuronal
activity, local field potentials (LFP), and expression
levels of plasticity-related immediate-early genes (IEG) arc
and zif-268 in rats exposed to novel spatio-tactile
experience. Post-experience firing rate increases were
strongest in SWS and lasted much longer in the cortex
(hours) than in the hippocampus (minutes). During REM sleep,
firing rates showed strong temporal dependence across brain
areas: cortical activation during experience predicted
hippocampal activity in the first post-experience hour,
while hippocampal activation during experience predicted
cortical activity in the third post-experience hour. Four
hours after experience, IEG expression was specifically
upregulated during REM sleep in the cortex, but not in the
hippocampus. Arc gene expression in the cortex was
proportional to LFP amplitude in the spindle-range (10-14
Hz) but not to firing rates, as expected from signals more
related to dendritic input than to somatic output. The
results indicate that hippocampo-cortical activation during
waking is followed by multiple waves of cortical plasticity
as full sleep cycles recur. The absence of equivalent
changes in the hippocampus may explain its mnemonic
disengagement over time.},
Doi = {10.3389/neuro.01.1.1.003.2007},
Key = {fds351214}
}
@article{fds351213,
Author = {Stapleton, JR and Lavine, ML and Nicolelis, MAL and Simon,
SA},
Title = {Ensembles of gustatory cortical neurons anticipate and
discriminate between tastants in a single
lick.},
Journal = {Frontiers in Neuroscience},
Volume = {1},
Number = {1},
Pages = {161-174},
Year = {2007},
Month = {November},
url = {http://dx.doi.org/10.3389/neuro.01.1.1.012.2007},
Abstract = {The gustatory cortex (GC) processes chemosensory and
somatosensory information and is involved in learning and
anticipation. Previously we found that a subpopulation of GC
neurons responded to tastants in a single lick (Stapleton et
al., 2006). Here we extend this investigation to determine
if small ensembles of GC neurons, obtained while rats
received blocks of tastants on a fixed ratio schedule (FR5),
can discriminate between tastants and their concentrations
after a single 50 muL delivery. In the FR5 schedule subjects
received tastants every fifth (reinforced) lick and the
intervening licks were unreinforced. The ensemble firing
patterns were analyzed with a Bayesian generalized linear
model whose parameters included the firing rates and
temporal patterns of the spike trains. We found that when
both the temporal and rate parameters were included, 12 of
13 ensembles correctly identified single tastant deliveries.
We also found that the activity during the unreinforced
licks contained signals regarding the identity of the
upcoming tastant, which suggests that GC neurons contain
anticipatory information about the next tastant delivery. To
support this finding we performed experiments in which
tastant delivery was randomized within each block and found
that the neural activity following the unreinforced licks
did not predict the upcoming tastant. Collectively, these
results suggest that after a single lick ensembles of GC
neurons can discriminate between tastants, that they may
utilize both temporal and rate information, and when the
tastant delivery is repetitive ensembles contain information
about the identity of the upcoming tastant
delivery.},
Doi = {10.3389/neuro.01.1.1.012.2007},
Key = {fds351213}
}
@article{fds275309,
Author = {Pantoja, J and Ribeiro, S and Wiest, M and Soares, E and Gervasoni, D and Lemos, NAM and Nicolelis, MAL},
Title = {Neuronal activity in the primary somatosensory
thalamocortical loop is modulated by reward contingency
during tactile discrimination.},
Journal = {Journal of Neuroscience},
Volume = {27},
Number = {39},
Pages = {10608-10620},
Year = {2007},
Month = {September},
ISSN = {0270-6474},
url = {http://dx.doi.org/10.1523/JNEUROSCI.5279-06.2007},
Abstract = {Delayed-response sensory discrimination is believed to
require primary sensory thalamus and cortex for early
stimulus identification and higher-order forebrain regions
for the late association of stimuli with rewarded motor
responses. Here we investigate neuronal responses in the rat
primary somatosensory cortex (S1) and ventral posterior
medial nucleus of the thalamus (VPM) during a tactile
discrimination task that requires animals to associate two
different tactile stimuli with two corresponding choices of
spatial trajectory to be rewarded. To manipulate reward
expectation, neuronal activity observed under regular reward
contingency (CR) was compared with neuronal activity
recorded during freely rewarded (FR) trials, in which
animals obtained reward regardless of their choice of
spatial trajectory. Across-trial firing rates of S1 and VPM
neurons varied according to the reward contingency of the
task. Analysis of neuronal ensemble activity by an
artificial neural network showed that stimulus-related
information in S1 and VPM increased from stimulus sampling
to reward delivery in CR trials but decreased to chance
levels when animals performed FR trials, when stimulus
discrimination was irrelevant for task execution. Neuronal
ensemble activity in VPM was only correlated with task
performance during stimulus presentation. In contrast, S1
neuronal activity was highly correlated with task
performance long after stimulus removal, a relationship that
peaked during the 300 ms that preceded reward delivery.
Together, our results indicate that neuronal activity in the
primary somatosensory thalamocortical loop is strongly
modulated by reward contingency.},
Doi = {10.1523/JNEUROSCI.5279-06.2007},
Key = {fds275309}
}
@article{fds275306,
Author = {Kim, HK and Carmena, JM and Biggs, SJ and Hanson, TL and Nicolelis, MAL and Srinivasan, MA},
Title = {The muscle activation method: an approach to impedance
control of brain-machine interfaces through a
musculoskeletal model of the arm.},
Journal = {Ieee Transactions on Bio Medical Engineering},
Volume = {54},
Number = {8},
Pages = {1520-1529},
Year = {2007},
Month = {August},
ISSN = {0018-9294},
url = {http://dx.doi.org/10.1109/TBME.2007.900818},
Abstract = {Current demonstrations of brain-machine interfaces (BMIs)
have shown the potential for controlling neuroprostheses
under pure motion control. For interaction with objects,
however, pure motion control lacks the information required
for versatile manipulation. This paper investigates the idea
of applying impedance control in a BMI system. An extraction
algorithm incorporating a musculoskeletal arm model was
developed for this purpose. The new algorithm, called the
muscle activation method (MAM), was tested on cortical
recordings from a behaving monkey. The MAM was found to
predict motion parameters with as much accuracy as a linear
filter. Furthermore, it successfully predicted limb
interactions with novel force fields, which is a new and
significant capability lacking in other algorithms.},
Doi = {10.1109/TBME.2007.900818},
Key = {fds275306}
}
@article{fds275351,
Author = {Zacksenhouse, M and Lebedev, MA and Carmena, JM and O'Doherty, JE and Henriquez, C and Nicolelis, MAL},
Title = {Cortical modulations increase in early sessions with
brain-machine interface.},
Journal = {Plos One},
Volume = {2},
Number = {7},
Pages = {e619},
Year = {2007},
Month = {July},
ISSN = {1932-6203},
url = {http://dx.doi.org/10.1371/journal.pone.0000619},
Abstract = {BACKGROUND: During planning and execution of reaching
movements, the activity of cortical motor neurons is
modulated by a diversity of motor, sensory, and cognitive
signals. Brain-machine interfaces (BMIs) extract part of
these modulations to directly control artificial actuators.
However, cortical modulations that emerge in the novel
context of operating the BMI are poorly understood.
METHODOLOGY/PRINCIPAL FINDINGS: Here we analyzed the changes
in neuronal modulations that occurred in different cortical
motor areas as monkeys learned to use a BMI to control
reaching movements. Using spike-train analysis methods we
demonstrate that the modulations of the firing-rates of
cortical neurons increased abruptly after the monkeys
started operating the BMI. Regression analysis revealed that
these enhanced modulations were not correlated with the
kinematics of the movement. The initial enhancement in
firing rate modulations declined gradually with subsequent
training in parallel with the improvement in behavioral
performance. CONCLUSIONS/SIGNIFICANCE: We conclude that the
enhanced modulations are related to computational tasks that
are significant especially in novel motor contexts. Although
the function and neuronal mechanism of the enhanced cortical
modulations are open for further inquiries, we discuss their
potential role in processing execution errors and
representing corrective or explorative activity. These
representations are expected to contribute to the formation
of internal models of the external actuator and their
decoding may facilitate BMI improvement.},
Doi = {10.1371/journal.pone.0000619},
Key = {fds275351}
}
@article{fds275359,
Author = {Costa, RM and Gutierrez, R and de Araujo, IE and Coelho, MRP and Kloth,
AD and Gainetdinov, RR and Caron, MG and Nicolelis, MAL and Simon,
SA},
Title = {Dopamine levels modulate the updating of tastant
values.},
Journal = {Genes, Brain, and Behavior},
Volume = {6},
Number = {4},
Pages = {314-320},
Year = {2007},
Month = {June},
ISSN = {1601-1848},
url = {http://www.ncbi.nlm.nih.gov/pubmed/16848782},
Abstract = {To survive, animals must constantly update the internal
value of stimuli they encounter; a process referred to as
incentive learning. Although there have been many studies
investigating whether dopamine is necessary for reward, or
for the association between stimuli and actions with
rewards, less is known about the role of dopamine in the
updating of the internal value of stimuli per se. We used a
single-bottle forced-choice task to investigate the role of
dopamine in learning the value of tastants. We show that
dopamine transporter knock-out mice (DAT-KO), which have
constitutively elevated dopamine levels, develop a more
positive bias towards a hedonically positive tastant
(sucrose 400 mM) than their wild-type littermates.
Furthermore, when compared to wild-type littermates, DAT-KO
mice develop a less negative bias towards a hedonically
negative tastant (quinine HCl 10 mM). Importantly, these
effects develop with training, because at the onset of
training DAT-KO and wild-type mice display similar biases
towards sucrose and quinine. These data suggest that
dopamine levels can modulate the updating of tastant values,
a finding with implications for understanding
sensory-specific motivation and reward seeking.},
Doi = {10.1111/j.1601-183X.2006.00257.x},
Key = {fds275359}
}
@article{fds275305,
Author = {Fitzsimmons, NA and Drake, W and Hanson, TL and Lebedev, MA and Nicolelis, MAL},
Title = {Primate reaching cued by multichannel spatiotemporal
cortical microstimulation.},
Journal = {Journal of Neuroscience},
Volume = {27},
Number = {21},
Pages = {5593-5602},
Year = {2007},
Month = {May},
ISSN = {0270-6474},
url = {http://dx.doi.org/10.1523/JNEUROSCI.5297-06.2007},
Abstract = {Both humans and animals can discriminate signals delivered
to sensory areas of their brains using electrical
microstimulation. This opens the possibility of creating an
artificial sensory channel that could be implemented in
neuroprosthetic devices. Although microstimulation delivered
through multiple implanted electrodes could be beneficial
for this purpose, appropriate microstimulation protocols
have not been developed. Here, we report a series of
experiments in which owl monkeys performed reaching
movements guided by spatiotemporal patterns of cortical
microstimulation delivered to primary somatosensory cortex
through chronically implanted multielectrode arrays. The
monkeys learned to discriminate microstimulation patterns,
and their ability to learn new patterns and new behavioral
rules improved during several months of testing.
Significantly, information was conveyed to the brain through
the interplay of microstimulation patterns delivered to
multiple electrodes and the temporal order in which these
electrodes were stimulated. This suggests multichannel
microstimulation as a viable means of sensorizing neural
prostheses.},
Doi = {10.1523/JNEUROSCI.5297-06.2007},
Key = {fds275305}
}
@article{fds275262,
Author = {de Araujo, IE and Nicolelis, MAL and Simon, SA},
Title = {Evolution of gustation},
Volume = {3},
Pages = {329-339},
Publisher = {Elsevier},
Year = {2007},
Month = {January},
url = {http://dx.doi.org/10.1016/B0-12-370878-8/00079-3},
Abstract = {The evolutionary success of most mammalian species results
in part from their ability to efficiently select nutrients
in order to maintain energy, fluid and temperature
homeostasis. It is shown that efficient ingestive behavior
depends on several structures located in the mammalian
cortex. Moreover, the anatomical and functional markers of
these structures were largely conserved across different
species. In particular, the mammalian gustatory cortex
achieves integration of visceral, metabolic, olfactory,
somatosensory and taste inputs in order to appropriately
control feeding. © 2007 Elsevier Inc. All rights
reserved.},
Doi = {10.1016/B0-12-370878-8/00079-3},
Key = {fds275262}
}
@article{fds275264,
Author = {Ribeiro, S and Nicolelis, MAL},
Title = {The evolution of neural systems for sleep and
dreaming},
Volume = {3},
Pages = {451-464},
Publisher = {Elsevier},
Year = {2007},
Month = {January},
url = {http://dx.doi.org/10.1016/B0-12-370878-8/00007-0},
Abstract = {Despite the importance of sleep and dreams for the
understanding of human consciousness, science is yet to
achieve a consensus about their functions and intricate
phenomenology. This article outlines an evolutionary theory
of how sleep and dreams were selected over time due to their
effects on cognition. The theory proposes that slow-wave
sleep (SWS) co-evolved with thalamocortical loops that
underlie sensory disconnection, from mere rest in
protoreptiles to an extended and periodic quiescent state
able to promote offline memory reverberation in amniotes. A
second sleep state, characterized by short duration
(seconds) and high cerebral activity, co-evolved in
crocodiles, birds, and mammals with a complex set of
pontine, midbrain, and forebrain structures. This post-SWS
state, called rapid-eye-movement sleep (REM), induces genes
linked to the stabilization, strengthening, and propagation
of memories. Extended single REM episodes lasting several
minutes evolved exclusively in the mammalian lineage.
Prolongation of the noisy mnemonic reverberation that
characterizes REM likely facilitates memory restructuring
('insight') rather than memory strengthening. Dreams as
narratives require the activation of selected cortical and
subcortical regions related to mnemonic representation and
reward. During dreams, memory fragments are concatenated so
as to simulate past events and future expectations. The
fitness-enhancing function of dreams is to enact potential
solutions for the cognitive challenges facing the dreamer.
Though probabilistic, dreams can at times yield accurate
predictions of future events, a fact of documented
importance throughout human history. Finally, it is possible
for extant humans to experience an enhanced REM state in
which dream events are under partial or total voluntary
control. Such lucid dreams likely require prefrontal
activity, and their cognitive potential remains uncharted
territory for science. © 2007 Elsevier Inc. All rights
reserved.},
Doi = {10.1016/B0-12-370878-8/00007-0},
Key = {fds275264}
}
@article{071410526096,
Author = {Zachsenhouse, M and Nemets, S and Yoffe, A and Ben-Haim, Y and Lebedev,
MA and Nicolelis, MAL},
Title = {An INFO-GAP approach to linear regression},
Journal = {2015 Ieee International Conference on Acoustics, Speech, and
Signal Processing (Icassp)},
Volume = {3},
Pages = {III800-III803},
Address = {Toulouse, France},
Year = {2006},
Month = {December},
ISSN = {1520-6149},
Keywords = {Mathematical models;Optimization;Parameter
estimation;Probability;Problem solving;Uncertainty
analysis;},
Abstract = {Linear regression with high uncertainties in the
measurements, model structure and model permanence is a
major challenging problem. Standard regression techniques
are based on optimizing a certain performance criterion,
usually the mean squared error, and are highly sensitive to
uncertainties. Regularization methods have been developed to
address the problem of measurement uncertainty, but choosing
the regularization parameter under severe uncertainties is
problematic. Here we develop an alternative regression
methodology based on satisficing rather than optimizing the
performance criterion while maximizing the robustness to
uncertainties. Uncertainties are represented by info-gap
models which entail an unbounded family of nested sets of
measurements parameterized by a non-probabilistic horizon of
uncertainty. We prove and demonstrate that the
robust-satisficing solution is different from the optimal
least squares solution and that the infogap approach can
provide higher robustness to uncertainty. © 2006
IEEE.},
Key = {071410526096}
}
@article{fds275299,
Author = {Nicolelis, MAL and Ribeiro, S},
Title = {Seeking the neural code.},
Journal = {Scientific American},
Volume = {295},
Number = {6},
Pages = {70-77},
Year = {2006},
Month = {December},
ISSN = {0036-8733},
url = {http://dx.doi.org/10.1038/scientificamerican1206-70},
Abstract = {The process through which the electrical pulses occurring
across the brain is translated into information is
discussed. The electrical pulses passing through central
nervous system translate into thoughts, emotions and
sensations, to understand the neural languages. These
electrical signals are conveyed through many peripheral
nerves throughout the body that are connected through brain,
thus forming the neural circuits called somatosensory
system. Receptive field term is used by the sensory
neurophysiologists to define the stimulated skin area that
causes the neurons to respond by action potentials.
Anesthetized rat models were used for the verification of
the procedure, and whiskers were found on the individual
neurons located in their multiple cortical barrels. The
individual neuron was able to respond to the deflection of
whiskers. The new technique of addition of electrode
materials have made the permanent implantation of the
recording devices in the brains.},
Doi = {10.1038/scientificamerican1206-70},
Key = {fds275299}
}
@article{fds275302,
Author = {Lin, S-C and Gervasoni, D and Nicolelis, MAL},
Title = {Fast modulation of prefrontal cortex activity by basal
forebrain noncholinergic neuronal ensembles.},
Journal = {Journal of Neurophysiology},
Volume = {96},
Number = {6},
Pages = {3209-3219},
Year = {2006},
Month = {December},
ISSN = {0022-3077},
url = {http://dx.doi.org/10.1152/jn.00524.2006},
Abstract = {Traditionally, most basal forebrain (BF) functions have been
attributed to its cholinergic neurons. However, the majority
of cortical-projecting BF neurons are noncholinergic and
their in vivo functions remain unclear. We investigated how
BF modulates cortical dynamics by simultaneously recording
</=50 BF single neurons along with local field potentials
(LFPs) from the prefrontal cortex (PFCx) in different
wake-sleep states of adult rats. Using stereotypical spike
time correlations, we identified a large (roughly 70%)
subset of BF neurons, which we named BF tonic neurons
(BFTNs). BFTNs fired tonically at 2-8 Hz without
significantly changing their average firing rate across
wake-sleep states. As such, these cannot be classified as
cholinergic neurons. BFTNs substantially increased the
spiking variability during waking and rapid-eye-movement
sleep, by exhibiting frequent spike bursts with <50-ms
interspike interval. Spike bursts among BFTNs were highly
correlated, leading to transient population synchronization
events of BFTN ensembles that lasted on average 160 ms. Most
importantly, BFTN synchronization occurred preferentially
just before the troughs of PFCx LFP oscillations, which
reflect increased cortical activity. Furthermore, BFTN
synchronization was accompanied by transient increases in
prefrontal cortex gamma oscillations. These results suggest
that synchronization of BFTN ensembles, which are likely to
be formed by cortical-projecting GABAergic neurons from the
BF, could be primarily responsible for fast cortical
modulations to provide transient amplification of cortical
activity.},
Doi = {10.1152/jn.00524.2006},
Key = {fds275302}
}
@article{fds275358,
Author = {Dzirasa, K and Ribeiro, S and Costa, R and Santos, LM and Lin, SC and Grosmark, A and Sotnikova, TD and Gainetdinov, RR and Caron, MG and Nicolelis, MAL},
Title = {Erratum: Dopaminergic Control of Sleep-Wake States (Journal
of Neuroscience (October 11, 2006) (10577-10589))},
Journal = {The Journal of Neuroscience : the Official Journal of the
Society for Neuroscience},
Volume = {26},
Number = {47},
Year = {2006},
Month = {November},
ISSN = {0270-6474},
Key = {fds275358}
}
@article{fds275303,
Author = {Simon, SA and de Araujo, IE and Gutierrez, R and Nicolelis,
MAL},
Title = {The neural mechanisms of gustation: a distributed processing
code.},
Journal = {Nature Reviews. Neuroscience},
Volume = {7},
Number = {11},
Pages = {890-901},
Year = {2006},
Month = {November},
ISSN = {1471-003X},
url = {http://www.ncbi.nlm.nih.gov/pubmed/17053812},
Abstract = {Whenever food is placed in the mouth, taste receptors are
stimulated. Simultaneously, different types of sensory fibre
that monitor several food attributes such as texture,
temperature and odour are activated. Here, we evaluate taste
and oral somatosensory peripheral transduction mechanisms as
well as the multi-sensory integrative functions of the
central pathways that support the complex sensations that we
usually associate with gustation. On the basis of recent
experimental data, we argue that these brain circuits make
use of distributed ensemble codes that represent the sensory
and post-ingestive properties of tastants.},
Doi = {10.1038/nrn2006},
Key = {fds275303}
}
@article{fds275357,
Author = {Costa, RM and Lin, S-C and Sotnikova, TD and Cyr, M and Gainetdinov, RR and Caron, MG and Nicolelis, MAL},
Title = {Rapid alterations in corticostriatal ensemble coordination
during acute dopamine-dependent motor dysfunction.},
Journal = {Neuron},
Volume = {52},
Number = {2},
Pages = {359-369},
Year = {2006},
Month = {October},
ISSN = {0896-6273},
url = {http://www.ncbi.nlm.nih.gov/pubmed/17046697},
Abstract = {Dopaminergic dysregulation can cause motor dysfunction, but
the mechanisms underlying dopamine-related motor disorders
remain under debate. We used an inducible and reversible
pharmacogenetic approach in dopamine transporter knockout
mice to investigate the simultaneous activity of neuronal
ensembles in the dorsolateral striatum and primary motor
cortex during hyperdopaminergia ( approximately 500% of
controls) with hyperkinesia, and after rapid and profound
dopamine depletion (<0.2%) with akinesia in the same animal.
Surprisingly, although most cortical and striatal neurons (
approximately 70%) changed firing rate during the transition
between dopamine-related hyperkinesia and akinesia, the
overall cortical firing rate remained unchanged. Conversely,
neuronal oscillations and ensemble activity coordination
within and between cortex and striatum did change rapidly
between these periods. During hyperkinesia, corticostriatal
activity became largely asynchronous, while during
dopamine-depletion the synchronicity increased. Thus,
dopamine-related disorders like Parkinson's disease may not
stem from changes in the overall levels of cortical
activity, but from dysfunctional activity coordination in
corticostriatal circuits.},
Doi = {10.1016/j.neuron.2006.07.030},
Key = {fds275357}
}
@article{fds275356,
Author = {Dzirasa, K and Ribeiro, S and Costa, R and Santos, LM and Lin, S-C and Grosmark, A and Sotnikova, TD and Gainetdinov, RR and Caron, MG and Nicolelis, MAL},
Title = {Dopaminergic control of sleep-wake states.},
Journal = {Journal of Neuroscience},
Volume = {26},
Number = {41},
Pages = {10577-10589},
Year = {2006},
Month = {October},
url = {http://www.ncbi.nlm.nih.gov/pubmed/17035544},
Abstract = {Dopamine depletion is involved in the pathophysiology of
Parkinson's disease, whereas hyperdopaminergia may play a
fundamental role in generating endophenotypes associated
with schizophrenia. Sleep disturbances are known to occur in
both schizophrenia and Parkinson's disease, suggesting that
dopamine plays a role in regulating the sleep-wake cycle.
Here, we show that novelty-exposed hyperdopaminergic mice
enter a novel awake state characterized by spectral patterns
of hippocampal local field potentials that resemble
electrophysiological activity observed during
rapid-eye-movement (REM) sleep. Treatment with haloperidol,
a D2 dopamine receptor antagonist, reduces this abnormal
intrusion of REM-like activity during wakefulness.
Conversely, mice acutely depleted of dopamine enter a
different novel awake state characterized by spectral
patterns of hippocampal local field potentials that resemble
electrophysiological activity observed during slow-wave
sleep (SWS). This dopamine-depleted state is marked by an
apparent suppression of SWS and a complete suppression of
REM sleep. Treatment with D2 (but not D1) dopamine receptor
agonists recovers REM sleep in these mice. Altogether, these
results indicate that dopamine regulates the generation of
sleep-wake states. We propose that psychosis and the sleep
disturbances experienced by Parkinsonian patients result
from dopamine-mediated disturbances of REM
sleep.},
Doi = {10.1523/JNEUROSCI.1767-06.2006},
Key = {fds275356}
}
@article{fds275300,
Author = {Lebedev, MA and Nicolelis, MAL},
Title = {Brain-machine interfaces: past, present and
future.},
Journal = {Trends in Neurosciences},
Volume = {29},
Number = {9},
Pages = {536-546},
Year = {2006},
Month = {September},
ISSN = {0166-2236},
url = {http://dx.doi.org/10.1016/j.tins.2006.07.004},
Abstract = {Since the original demonstration that electrical activity
generated by ensembles of cortical neurons can be employed
directly to control a robotic manipulator, research on
brain-machine interfaces (BMIs) has experienced an
impressive growth. Today BMIs designed for both experimental
and clinical studies can translate raw neuronal signals into
motor commands that reproduce arm reaching and hand grasping
movements in artificial actuators. Clearly, these
developments hold promise for the restoration of limb
mobility in paralyzed subjects. However, as we review here,
before this goal can be reached several bottlenecks have to
be passed. These include designing a fully implantable
biocompatible recording device, further developing real-time
computational algorithms, introducing a method for providing
the brain with sensory feedback from the actuators, and
designing and building artificial prostheses that can be
controlled directly by brain-derived signals. By reaching
these milestones, future BMIs will be able to drive and
control revolutionary prostheses that feel and act like the
human arm.},
Doi = {10.1016/j.tins.2006.07.004},
Key = {fds275300}
}
@article{fds275301,
Author = {de Araujo, IE and Gutierrez, R and Oliveira-Maia, AJ and Pereira, A and Nicolelis, MAL and Simon, SA},
Title = {Neural ensemble coding of satiety states.},
Journal = {Neuron},
Volume = {51},
Number = {4},
Pages = {483-494},
Year = {2006},
Month = {August},
ISSN = {0896-6273},
url = {http://www.ncbi.nlm.nih.gov/pubmed/16908413},
Abstract = {The motivation to start or terminate a meal involves the
continual updating of information on current body status by
central gustatory and reward systems. Previous
electrophysiological and neuroimaging investigations
revealed region-specific decreases in activity as the
subject's state transitions from hunger to satiety. By
implanting bundles of microelectrodes in the lateral
hypothalamus, orbitofrontal cortex, insular cortex, and
amygdala of hungry rats that voluntarily eat to satiety, we
have measured the behavior of neuronal populations through
the different phases of a complete feeding cycle
(hunger-satiety-hunger). Our data show that while most
satiety-sensitive units preferentially responded to a unique
hunger phase within a cycle, neuronal populations integrated
single-unit information in order to reflect the animal's
motivational state across the entire cycle, with higher
activity levels during the hunger phases. This distributed
population code might constitute a neural mechanism
underlying meal initiation under different metabolic
states.},
Doi = {10.1016/j.neuron.2006.07.009},
Key = {fds275301}
}
@article{9020704,
Author = {Kim, S-P and Sanchez, JC and Rao, YN and Erdogmus, D and Carmena, JM and Lebedev, MA and Nicolelis, MAL and Principe, JC},
Title = {A comparison of optimal MIMO linear and nonlinear models for
brain-machine interfaces.},
Journal = {Journal of Neural Engineering},
Volume = {3},
Number = {2},
Pages = {145-161},
Year = {2006},
Month = {June},
ISSN = {1741-2560},
url = {http://dx.doi.org/10.1088/1741-2560/3/2/009},
Keywords = {brain;delays;generalisation (artificial intelligence);medical
signal processing;MIMO systems;neural nets;neurophysiology;user
interfaces;Wiener filters;},
Abstract = {The field of brain-machine interfaces requires the
estimation of a mapping from spike trains collected in motor
cortex areas to the hand kinematics of the behaving animal.
This paper presents a systematic investigation of several
linear (Wiener filter, LMS adaptive filters, gamma filter,
subspace Wiener filters) and nonlinear models (time-delay
neural network and local linear switching models) applied to
datasets from two experiments in monkeys performing motor
tasks (reaching for food and target hitting). Ensembles of
100-200 cortical neurons were simultaneously recorded in
these experiments, and even larger neuronal samples are
anticipated in the future. Due to the large size of the
models (thousands of parameters), the major issue studied
was the generalization performance. Every parameter of the
models (not only the weights) was selected optimally using
signal processing and machine learning techniques. The
models were also compared statistically with respect to the
Wiener filter as the baseline. Each of the optimization
procedures produced improvements over that baseline for
either one of the two datasets or both.},
Doi = {10.1088/1741-2560/3/2/009},
Key = {9020704}
}
@article{8927250,
Author = {Kim, HK and Biggs, SJ and Schloerb, DW and Carmena, JM and Lebedev, MA and Nicolelis, MAL and Srinivasan, MA},
Title = {Continuous shared control for stabilizing reaching and
grasping with brain-machine interfaces.},
Journal = {Ieee Transactions on Bio Medical Engineering},
Volume = {53},
Number = {6},
Pages = {1164-1173},
Year = {2006},
Month = {June},
ISSN = {0018-9294},
url = {http://dx.doi.org/10.1109/TBME.2006.870235},
Keywords = {brain;handicapped aids;medical control systems;neurophysiology;prosthetics;telerobotics;},
Abstract = {Research on brain-machine interfaces (BMI's) is directed
toward enabling paralyzed individuals to manipulate their
environment through slave robots. Even for able-bodied
individuals, using a robot to reach and grasp objects in
unstructured environments can be a difficult
telemanipulation task. Controlling the slave directly with
neural signals instead of a hand-master adds further
challenges, such as uncertainty about the intended
trajectory coupled with a low update rate for the command
signal. To address these challenges, a continuous shared
control (CSC) paradigm is introduced for BMI where robot
sensors produce reflex-like reactions to augment
brain-controlled trajectories. To test the merits of this
approach, CSC was implemented on a 3-degree-of-freedom robot
with a gripper bearing three co-located range sensors. The
robot was commanded to follow eighty-three reach-and-grasp
trajectories estimated previously from the outputs of a
population of neurons recorded from the brain of a monkey.
Five different levels of sensor-based reflexes were tested.
Weighting brain commands 70% and sensor commands 30%
produced the best task performance, better than brain
signals alone by more than seven-fold. Such a marked
performance improvement in this test case suggests that some
level of machine autonomy will be an important component of
successful BMI systems in general.},
Doi = {10.1109/TBME.2006.870235},
Key = {8927250}
}
@article{fds275297,
Author = {Stapleton, JR and Lavine, ML and Wolpert, RL and Nicolelis, MAL and Simon, SA},
Title = {Rapid taste responses in the gustatory cortex during
licking.},
Journal = {Journal of Neuroscience},
Volume = {26},
Number = {15},
Pages = {4126-4138},
Year = {2006},
Month = {April},
url = {http://www.ncbi.nlm.nih.gov/pubmed/16611830},
Abstract = {Rapid tastant detection is necessary to prevent the
ingestion of potentially poisonous compounds. Behavioral
studies have shown that rats can identify tastants in
approximately 200 ms, although the electrophysiological
correlates for fast tastant detection have not been
identified. For this reason, we investigated whether neurons
in the primary gustatory cortex (GC), a cortical area
necessary for tastant identification and discrimination,
contain sufficient information in a single lick cycle, or
approximately 150 ms, to distinguish between tastants at
different concentrations. This was achieved by recording
neural activity in GC while rats licked four times without a
liquid reward, and then, on the fifth lick, received a
tastant (FR5 schedule). We found that 34% (61 of 178) of GC
units were chemosensitive. The remaining neurons were
activated during some phase of the licking cycle,
discriminated between reinforced and unreinforced licks, or
processed task-related information. Chemosensory neurons
exhibited a latency of 70-120 ms depending on concentration,
and a temporally precise phasic response that returned to
baseline in tens of milliseconds. Tastant-responsive neurons
were broadly tuned and responded to increasing tastant
concentrations by either increasing or decreasing their
firing rates. In addition, some responses were only evoked
at intermediate tastant concentrations. In summary, these
results suggest that the gustatory cortex is capable of
processing multimodal information on a rapid timescale and
provide the physiological basis by which animals may
discriminate between tastants during a single lick
cycle.},
Doi = {10.1523/JNEUROSCI.0092-06.2006},
Key = {fds275297}
}
@article{fds275296,
Author = {Gutierrez, R and Carmena, JM and Nicolelis, MAL and Simon,
SA},
Title = {Orbitofrontal ensemble activity monitors licking and
distinguishes among natural rewards.},
Journal = {Journal of Neurophysiology},
Volume = {95},
Number = {1},
Pages = {119-133},
Year = {2006},
Month = {January},
ISSN = {0022-3077},
url = {http://www.ncbi.nlm.nih.gov/pubmed/16120664},
Abstract = {The classification of rhythmic licking into clusters has
proved to be useful for characterizing brain mechanisms that
modulate the ingestion of natural rewards (sucrose and
water). One cortical area that is responsive to rewarding
stimuli is the orbitofrontal cortex (OFC). However, it is
not presently known how OFC neurons respond while rodents
freely lick for natural rewards and whether these responses
are related to the structure of licking clusters. We
addressed these issues by showing that temporary
inactivation of the OFC decreases the duration and increases
the number of clusters and that the activity of OFC neurons
changed at precise times before, during, and after the
cluster terminates. Furthermore, analysis of the activity of
OFC neuronal ensembles showed that they could discriminate
cluster onset from termination, predict when a behaving
animal will begin a cluster, and distinguish and anticipate
between natural rewards. These results provide a new role
for the OFC in influencing licking clusters and anticipating
specific rewards.},
Doi = {10.1152/jn.00467.2005},
Key = {fds275296}
}
@article{fds275304,
Author = {Darmanjian, S and Kim, SP and Nechyba, MC and Principe, J and Wessberg,
J and Nicolelis, MAL},
Title = {Independently coupled HMM switching classifier for a bimodel
brain-machine interface},
Journal = {Proceedings of the 2006 16th Ieee Signal Processing Society
Workshop on Machine Learning for Signal Processing, Mlsp
2006},
Pages = {379-384},
Publisher = {IEEE},
Year = {2006},
Month = {January},
url = {http://dx.doi.org/10.1109/MLSP.2006.275579},
Abstract = {Our initial attempt to develop a switching classifier used
vector quantization to compress the multi-dimensional neural
data recorded from multiple cortical areas of an owl monkey,
into a discrete symbol for use in a single Hidden Markov
Model (HMM) or HMM chain. After classification, different
neural data is delegated to local linear predictors when the
monkey's arm is moving and when it is at rest. This
multiple-model approach helped to validate the hypothesis
that by switching the neuronal firing data, the performance
of the final linear prediction is improved. In this paper,
we take the idea of using multiple models a step further and
apply the concept to our actual switching classifier. This
new structure uses an ensemble of single neural-channel HMM
chains to form an Independently Coupled Hidden Markov Model
(ICHMM). Consequently, this classifier takes advantage of
the neural firing properties and allows for the removal of
Vector Quantization while jointly improving the
classification performance and the subsequent linear
prediction of the trajectory. © 2006 IEEE.},
Doi = {10.1109/MLSP.2006.275579},
Key = {fds275304}
}
@article{06239919050,
Author = {Kim, SP and Carmena, JM and Nicolelis, MA and Principe,
JC},
Title = {Multiresolution representations and data mining of neural
spikes for brain-machine interfaces},
Journal = {2nd International Ieee Embs Conference on Neural
Engineering},
Volume = {2005},
Pages = {221-224},
Publisher = {IEEE},
Address = {Arlington, VA, United States},
Year = {2005},
Month = {December},
url = {http://dx.doi.org/10.1109/CNE.2005.1419596},
Keywords = {Data mining;Neurology;Interfaces (computer);Optical
resolving power;Mathematical models;},
Abstract = {In brain-machine interface (BMI) applications, neural firing
activities have been represented by spike counts with a
fixed-width time bin. Adaptive models have been designed to
utilize these bin counts for mapping the associated behavior
which is typically 2D or 3D hand movement. However, the
representation of the firing activities can be enriched by
binning neural spikes with multiple time scales based on
multiresolution analysis. This multiresolution
representation of neural activities can provide more
accurate prediction of the hand movement parameters. Data
mining techniques must be applied to models using
multiresolution representation in order to avoid
overfitting. In this paper, we demonstrate that the
multiresolution representation improves the performance of
the linear model for BMIs compared to the model with the
fixed-width time bin. © 2005 IEEE.},
Doi = {10.1109/CNE.2005.1419596},
Key = {06239919050}
}
@article{8897550,
Author = {Kim, SP and Rao, YN and Erdogmus, D and Sanchez, JC and Nicolelis, MAL and Principe, JC},
Title = {Determining patterns in neural activity for reaching
movements using nonnegative matrix factorization},
Journal = {Eurasip Journal on Applied Signal Processing},
Volume = {2005},
Number = {19},
Pages = {3113-3121},
Publisher = {Springer Nature},
Year = {2005},
Month = {December},
ISSN = {1110-8657},
url = {http://dx.doi.org/10.1155/ASP.2005.3113},
Keywords = {brain;matrix decomposition;medical signal
processing;neurophysiology;spatiotemporal
phenomena;},
Abstract = {We propose the use of nonnegative matrix factorization (NMF)
as a model-independent methodology to analyze neural
activity. We demonstrate that, using this technique, it is
possible to identify local spatiotemporal patterns of neural
activity in the form of sparse basis vectors. In addition,
the sparseness of these bases can help infer correlations
between cortical firing patterns and behavior. We
demonstrate the utility of this approach using neural
recordings collected in a brain-machine interface (BMI)
setting. The results indicate that, using the NMF analysis,
it is possible to improve the performance of BMI models
through appropriate pruning of inputs. © 2005 Hindawi
Publishing Corporation.},
Doi = {10.1155/ASP.2005.3113},
Key = {8897550}
}
@article{fds275350,
Author = {Carmena, JM and Lebedev, MA and Henriquez, CS and Nicolelis,
MAL},
Title = {Stable ensemble performance with single-neuron variability
during reaching movements in primates.},
Journal = {Journal of Neuroscience},
Volume = {25},
Number = {46},
Pages = {10712-10716},
Year = {2005},
Month = {November},
url = {http://www.ncbi.nlm.nih.gov/pubmed/16291944},
Abstract = {Significant variability in firing properties of individual
neurons was observed while two monkeys, chronically
implanted with multielectrode arrays in frontal and parietal
cortical areas, performed a continuous arm movement task.
Although the degree of correlation between the firing of
single neurons and movement parameters was nonstationary,
stable predictions of arm movements could be obtained from
the activity of neuronal ensembles. This result adds support
to the idea that movement parameters are redundantly encoded
in the motor cortex, such that brain networks can achieve
the same behavioral goals through different patterns and
relative contribution of individual neuron activity. This
has important implications for neural prosthetics,
suggesting that accurate operation of a brain-machine
interface requires recording from large neuronal ensembles
to minimize the effect of variability and ensuring stable
performance over long periods of time.},
Doi = {10.1523/JNEUROSCI.2772-05.2005},
Key = {fds275350}
}
@article{fds275295,
Author = {Santucci, DM and Kralik, JD and Lebedev, MA and Nicolelis,
MAL},
Title = {Frontal and parietal cortical ensembles predict single-trial
muscle activity during reaching movements in
primates.},
Journal = {The European Journal of Neuroscience},
Volume = {22},
Number = {6},
Pages = {1529-1540},
Year = {2005},
Month = {September},
ISSN = {0953-816X},
url = {http://dx.doi.org/10.1111/j.1460-9568.2005.04320.x},
Abstract = {Previously we have shown that the kinematic parameters of
reaching movements can be extracted from the activity of
cortical ensembles. Here we used cortical ensemble activity
to predict electromyographic (EMG) signals of four arm
muscles in New World monkeys. The overall shape of the EMG
envelope was predicted, as well as trial-to-trial variations
in the amplitude and timing of bursts of muscle activity.
Predictions of EMG patterns exhibited during reaching
movements could be obtained not only from primary motor
cortex, but also from dorsal premotor, primary somatosensory
and posterior parietal cortices. These results suggest that
these areas represent signals correlated to EMGs of arm
muscles in a distributed manner, and that the larger the
population sampled, the more reliable the predictions. We
propose that, in the future, recordings from multiple
cortical areas and the extraction of muscle patterns from
these recordings will help to restore limb mobility in
paralysed patients.},
Doi = {10.1111/j.1460-9568.2005.04320.x},
Key = {fds275295}
}
@article{fds275294,
Author = {Nicolelis, MAL},
Title = {Computing with thalamocortical ensembles during different
behavioural states.},
Journal = {The Journal of Physiology},
Volume = {566},
Number = {Pt 1},
Pages = {37-47},
Year = {2005},
Month = {July},
url = {http://dx.doi.org/10.1113/jphysiol.2005.083709},
Abstract = {A series of recent studies have indicated that ensembles of
neurones, distributed within the neural structures that form
the primary thalamocortical loop (TCL) of the trigeminal
component of the rat somatosensory system, change the way
they respond to similar tactile stimuli, according to both
the behavioural strategy employed by animals to gather
information and the animal's internal brain states. These
findings suggest that top-down influences, which are more
likely to play a role during active discrimination than
during passive whisker stimulation, may alter the pattern of
neuronal firing within both the distinct layers of the
primary somatosensory cortex (S1) and the ventral posterior
medial nucleus (VPM). We propose that through this
physiological process, which involves concurrent dynamic
modulations at both cellular and circuit levels in the TCL,
rats can either optimize the detection of novel or hard to
sense stimuli or they can analyse complex patterns of
multi-whisker stimulation, during natural exploration of
their surrounding environment.},
Doi = {10.1113/jphysiol.2005.083709},
Key = {fds275294}
}
@article{8473631,
Author = {Sanchez, JC and Erdogmus, D and Nicolelis, MAL and Wessberg, J and Principe, JC},
Title = {Interpreting spatial and temporal neural activity through a
recurrent neural network brain-machine interface.},
Journal = {Ieee Transactions on Neural Systems and Rehabilitation
Engineering : a Publication of the Ieee Engineering in
Medicine and Biology Society},
Volume = {13},
Number = {2},
Pages = {213-219},
Year = {2005},
Month = {June},
url = {http://dx.doi.org/10.1109/TNSRE.2005.847382},
Keywords = {bioelectric phenomena;biomechanics;brain;handicapped
aids;medical signal processing;neurophysiology;nonlinear
dynamical systems;physiological models;recurrent neural
nets;spatiotemporal phenomena;},
Abstract = {We propose the use of optimized brain-machine interface
(BMI) models for interpreting the spatial and temporal
neural activity generated in motor tasks. In this study, a
nonlinear dynamical neural network is trained to predict the
hand position of primates from neural recordings in a
reaching task paradigm. We first develop a method to reveal
the role attributed by the model to the sampled motor,
premotor, and parietal cortices in generating hand
movements. Next, using the trained model weights, we derive
a temporal sensitivity measure to asses how the model
utilized the sampled cortices and neurons in real-time
during BMI testing.},
Doi = {10.1109/tnsre.2005.847382},
Key = {8473631}
}
@article{fds275349,
Author = {Lebedev, MA and Carmena, JM and O'Doherty, JE and Zacksenhouse, M and Henriquez, CS and Principe, JC and Nicolelis, MAL},
Title = {Cortical ensemble adaptation to represent velocity of an
artificial actuator controlled by a brain-machine
interface.},
Journal = {Journal of Neuroscience},
Volume = {25},
Number = {19},
Pages = {4681-4693},
Year = {2005},
Month = {May},
url = {http://www.ncbi.nlm.nih.gov/pubmed/15888644},
Abstract = {Monkeys can learn to directly control the movements of an
artificial actuator by using a brain-machine interface (BMI)
driven by the activity of a sample of cortical neurons.
Eventually, they can do so without moving their limbs.
Neuronal adaptations underlying the transition from control
of the limb to control of the actuator are poorly
understood. Here, we show that rapid modifications in
neuronal representation of velocity of the hand and actuator
occur in multiple cortical areas during the operation of a
BMI. Initially, monkeys controlled the actuator by moving a
hand-held pole. During this period, the BMI was trained to
predict the actuator velocity. As the monkeys started using
their cortical activity to control the actuator, the
activity of individual neurons and neuronal populations
became less representative of the animal's hand movements
while representing the movements of the actuator. As a
result of this adaptation, the animals could eventually stop
moving their hands yet continue to control the actuator.
These results show that, during BMI control, cortical
ensembles represent behaviorally significant motor
parameters, even if these are not associated with movements
of the animal's own limb.},
Doi = {10.1523/JNEUROSCI.4088-04.2005},
Key = {fds275349}
}
@article{fds275293,
Author = {Wiest, MC and Bentley, N and Nicolelis, MAL},
Title = {Heterogeneous integration of bilateral whisker signals by
neurons in primary somatosensory cortex of awake
rats.},
Journal = {Journal of Neurophysiology},
Volume = {93},
Number = {5},
Pages = {2966-2973},
Year = {2005},
Month = {May},
url = {http://dx.doi.org/10.1152/jn.00556.2004},
Abstract = {Bilateral single-unit recordings in primary somatosensory
cortex (S1) of anesthetized rats have revealed substantial
cross talk between cortical hemispheres, suggesting the
possibility that behaviorally relevant bilateral integration
could occur in S1. To determine the extent of bilateral
neural responses in awake animals, we recorded S1 multi- and
single-unit activity in head-immobilized rats while
stimulating groups of 4 whiskers from the same column on
both sides of the head. Results from these experiments
confirm the widespread presence of single units responding
to tactile stimuli on either side of the face in S1 of awake
animals. Quantification of bilateral integration by
multiunits revealed both facilitative and suppressive
integration of bilateral inputs. Varying the interval
between left and right whisker stimuli between 0 and 120 ms
showed the temporal integration of bilateral stimuli to be
dominated on average by suppression at intervals around 30
ms, in agreement with comparable recordings in anesthetized
animals. Contrary to the anesthetized data, in the awake
animals we observed a high level of heterogeneity of
bilateral responses and a strong interaction between
synchronous bilateral stimuli. The results challenge the
traditional conception of highly segregated hemispheric
processing channels in the rat S1 cortex, and support the
hypothesis that callosal cross-projections between the two
hemispheres mediate rats' known ability to integrate
bilateral whisker signals.},
Doi = {10.1152/jn.00556.2004},
Key = {fds275293}
}
@article{fds275289,
Author = {Costa, RM and Liu, L and Nicolelis, MAL and Simon,
SA},
Title = {Gustatory effects of capsaicin that are independent of TRPV1
receptors.},
Journal = {Chemical Senses},
Volume = {30 Suppl 1},
Pages = {i198-i200},
Year = {2005},
Month = {January},
url = {http://www.ncbi.nlm.nih.gov/pubmed/15738113},
Doi = {10.1093/chemse/bjh183},
Key = {fds275289}
}
@article{fds275290,
Author = {Ribeiro, S and Nicolelis, MAL},
Title = {Reverberation, storage, and postsynaptic propagation of
memories during sleep (vol 11, pg 686, 2004)},
Journal = {Learning & Memory (Cold Spring Harbor, N.Y.)},
Volume = {12},
Number = {1},
Pages = {75-75},
Publisher = {COLD SPRING HARBOR LAB PRESS, PUBLICATIONS
DEPT},
Year = {2005},
Month = {January},
ISSN = {1072-0502},
Key = {fds275290}
}
@article{06229905160,
Author = {Rao, YN and Kim, SP and Sanchez, JC and Erdogmus, D and Principe, JC and Carmena, JM and Lebedev, MA and Nicolelis, MA},
Title = {Learning mappings in brain machine interfaces with echo
state networks},
Journal = {2015 Ieee International Conference on Acoustics, Speech, and
Signal Processing (Icassp)},
Volume = {V},
Pages = {V233-V236},
Publisher = {IEEE},
Address = {Philadelphia, PA, United States},
Year = {2005},
Month = {January},
ISSN = {1520-6149},
url = {http://dx.doi.org/10.1109/ICASSP.2005.1416283},
Keywords = {Learning systems;Computer networks;Neural
networks;Mathematical models;Mapping;Computational
complexity;Random processes;},
Abstract = {Brain Machine Interfaces (BMI) utilize linear or non-linear
models to map the neural activity to the associated behavior
which is typically the 2-D or 3-D hand position of a
primate. Linear models are plagued by the massive disparity
of the input and output dimensions thereby leading to poor
generalization. A solution would be to use non-linear models
like the Recurrent Multi-Layer Perceptron (RMLP) that
provide parsimonious mapping functions with better
generalization. However, this results in a drastic increase
in the training complexity, which can be critical for
practical use of a BMI. This paper bridges the gap between
superior performance per trained weight and model learning
complexity. Towards this end, we propose to use Echo State
Networks (ESN) to transform the neuronal firing activity
into a higher dimensional space and then derive an optimal
sparse linear mapping in the transformed space to match the
hand position. The sparse mapping is obtained using a weight
constrained cost function whose optimal solution is
determined using a stochastic gradient algorithm. © 2005
IEEE.},
Doi = {10.1109/ICASSP.2005.1416283},
Key = {06229905160}
}
@article{fds275287,
Author = {Gervasoni, D and Lin, S-C and Ribeiro, S and Soares, ES and Pantoja, J and Nicolelis, MAL},
Title = {Global forebrain dynamics predict rat behavioral states and
their transitions.},
Journal = {Journal of Neuroscience},
Volume = {24},
Number = {49},
Pages = {11137-11147},
Year = {2004},
Month = {December},
ISSN = {0270-6474},
url = {http://dx.doi.org/10.1523/JNEUROSCI.3524-04.2004},
Abstract = {The wake-sleep cycle, a spontaneous succession of global
brain states that correspond to major overt behaviors,
occurs in all higher vertebrates. The transitions between
these states, at once rapid and drastic, remain poorly
understood. Here, intracranial local field potentials (LFPs)
recorded in the cortex, hippocampus, striatum, and thalamus
were used to characterize the neurophysiological correlates
of the rat wake-sleep cycle. By way of a new method for the
objective classification and quantitative investigation of
all major brain states, we demonstrate that global brain
state transitions occur simultaneously across multiple
forebrain areas as specific spectral trajectories with
characteristic path, duration, and coherence bandwidth.
During state transitions, striking changes in neural
synchronization are effected by the prominent narrow-band
LFP oscillations that mark state boundaries. Our results
demonstrate that distant forebrain areas tightly coordinate
the processing of neural information during and between
global brain states, indicating a very high degree of
functional integration across the entire wake-sleep cycle.
We propose that transient oscillatory synchronization of
synaptic inputs, which underlie the rapid switching of
global brain states, may facilitate the exchange of
information within and across brain areas at the boundaries
of very distinct neural processing regimens.},
Doi = {10.1523/JNEUROSCI.3524-04.2004},
Key = {fds275287}
}
@article{fds275288,
Author = {Costa, RM and Cohen, D and Nicolelis, MAL},
Title = {Differential corticostriatal plasticity during fast and slow
motor skill learning in mice.},
Journal = {Current Biology : Cb},
Volume = {14},
Number = {13},
Pages = {1124-1134},
Year = {2004},
Month = {July},
url = {http://dx.doi.org/10.1016/j.cub.2004.06.053},
Abstract = {BACKGROUND: Motor skill learning usually comprises "fast"
improvement in performance within the initial training
session and "slow" improvement that develops across
sessions. Previous studies have revealed changes in activity
and connectivity in motor cortex and striatum during motor
skill learning. However, the nature and dynamics of the
plastic changes in each of these brain structures during the
different phases of motor learning remain unclear. RESULTS:
By using multielectrode arrays, we recorded the simultaneous
activity of neuronal ensembles in motor cortex and dorsal
striatum of mice during the different phases of skill
learning on an accelerating rotarod. Mice exhibited fast
improvement in the task during the initial session and also
slow improvement across days. Throughout training, a high
percentage of striatal (57%) and motor cortex (55%) neurons
were task related; i.e., changed their firing rate while
mice were running on the rotarod. Improvement in performance
was accompanied by substantial plastic changes in both
striatum and motor cortex. We observed parallel recruitment
of task-related neurons in both structures specifically
during the first session. Conversely, during slow learning
across sessions we observed differential refinement of the
firing patterns in each structure. At the neuronal ensemble
level, we observed considerable changes in activity within
the first session that became less evident during subsequent
sessions. CONCLUSIONS: These data indicate that cortical and
striatal circuits exhibit remarkable but dissociable
plasticity during fast and slow motor skill learning and
suggest that distinct neural processes mediate the different
phases of motor skill learning.},
Doi = {10.1016/j.cub.2004.06.053},
Key = {fds275288}
}
@article{fds275284,
Author = {Patil, PG and Carmena, JM and Nicolelis, MAL and Turner,
DA},
Title = {Ensemble recordings of human subcortical neurons as a source
of motor control signals for a brain-machine
interface.},
Journal = {Neurosurgery},
Volume = {55},
Number = {1},
Pages = {27-35},
Year = {2004},
Month = {July},
ISSN = {0148-396X},
url = {http://www.ncbi.nlm.nih.gov/pubmed/15214971},
Abstract = {OBJECTIVE: Patients with severe neurological injury, such as
quadriplegics, might benefit greatly from a brain-machine
interface that uses neuronal activity from motor centers to
control a neuroprosthetic device. Here, we report an
implementation of this strategy in the human intraoperative
setting to assess the feasibility of using neurons in
subcortical motor areas to drive a human brain-machine
interface. METHODS: Acute ensemble recordings from
subthalamic nucleus and thalamic motor areas (ventralis
oralis posterior [VOP]/ventralis intermediate nucleus [VIM])
were obtained in 11 awake patients during deep brain
stimulator surgery by use of a 32-microwire array. During
extracellular neuronal recordings, patients simultaneously
performed a visual feedback hand-gripping force task.
Offline analysis was then used to explore the relationship
between neuronal modulation and gripping force. RESULTS:
Individual neurons (n = 28 VOP/VIM, n = 119 subthalamic
nucleus) demonstrated a variety of modulation responses both
before and after onset of changes in gripping force of the
contralateral hand. Overall, 61% of subthalamic nucleus
neurons and 81% of VOP/VIM neurons modulated with gripping
force. Remarkably, ensembles of 3 to 55 simultaneously
recorded neurons were sufficiently information-rich to
predict gripping force during 30-second test periods with
considerable accuracy (up to R = 0.82, R(2) = 0.68) after
short training periods. Longer training periods and larger
neuronal ensembles were associated with improved predictive
accuracy. CONCLUSION: This initial feasibility study bridges
the gap between the nonhuman primate laboratory and the
human intraoperative setting to suggest that neuronal
ensembles from human subcortical motor regions may be able
to provide informative control signals to a future
brain-machine interface.},
Key = {fds275284}
}
@article{8044205,
Author = {Krupa, DJ and Wiest, MC and Shuler, MG and Laubach, M and Nicolelis,
MAL},
Title = {Layer-specific somatosensory cortical activation during
active tactile discrimination.},
Journal = {Science},
Volume = {304},
Number = {5679},
Pages = {1989-1992},
Year = {2004},
Month = {June},
url = {http://dx.doi.org/10.1126/science.1093318},
Keywords = {neurophysiology;touch (physiological);},
Abstract = {Ensemble neuronal activity was recorded in each layer of the
whisker area of the primary somatosensory cortex (SI) while
rats performed a whisker-dependent tactile discrimination
task. Comparison of this activity with SI activity evoked by
similar passive whisker stimulation revealed fundamental
differences in tactile signal processing during active and
passive stimulation. Moreover, significant layer-specific
functional differences in SI activity were observed during
active discrimination. These differences could not be
explained solely by variations in ascending thalamocortical
input to SI. Instead, these results suggest that top-down
influences during active discrimination may alter the
overall functional nature of SI as well as layer-specific
mechanisms of tactile processing.},
Doi = {10.1126/science.1093318},
Key = {8044205}
}
@article{04238197985,
Author = {Nicolelis, MAL and Birbaumer, N and Müller, KR},
Title = {Special issue on brain-machine interfaces:
Editorial},
Journal = {Ieee Transactions on Bio Medical Engineering},
Volume = {51},
Number = {6},
Pages = {877-880},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2004},
Month = {June},
url = {http://dx.doi.org/10.1109/TBME.2004.827677},
Doi = {10.1109/TBME.2004.827677},
Key = {04238197985}
}
@article{7981871,
Author = {Sanchez, JC and Carmena, JM and Lebedev, MA and Nicolelis, MAL and Harris, JG and Principe, JC},
Title = {Ascertaining the importance of neurons to develop better
brain-machine interfaces.},
Journal = {Ieee Transactions on Bio Medical Engineering},
Volume = {51},
Number = {6},
Pages = {943-953},
Year = {2004},
Month = {June},
url = {http://dx.doi.org/10.1109/TBME.2004.827061},
Keywords = {bioelectric potentials;biomechanics;cellular
biophysics;correlation methods;handicapped aids;medical
computing;neurophysiology;sensitivity analysis;},
Abstract = {In the design of brain-machine interface (BMI) algorithms,
the activity of hundreds of chronically recorded neurons is
used to reconstruct a variety of kinematic variables. A
significant problem introduced with the use of neural
ensemble inputs for model building is the explosion in the
number of free parameters. Large models not only affect
model generalization but also put a computational burden on
computing an optimal solution especially when the goal is to
implement the BMI in low-power, portable hardware. In this
paper, three methods are presented to quantitatively rate
the importance of neurons in neural to motor mapping, using
single neuron correlation analysis, sensitivity analysis
through a vector linear model, and a model-independent
cellular directional tuning analysis for comparisons
purpose. Although, the rankings are not identical, up to
sixty percent of the top 10 ranking cells were in common.
This set can then be used to determine a reduced-order model
whose performance is similar to that of the ensemble. It is
further shown that by pruning the initial ensemble neural
input with the ranked importance of cells, a reduced sets of
cells (between 40 and 80, depending upon the methods) can be
found that exceed the BMI performance levels of the full
ensemble.},
Doi = {10.1109/TBME.2004.827061},
Key = {7981871}
}
@article{7981869,
Author = {Bossetti, CA and Carmena, JM and Nicolelis, MAL and Wolf,
PD},
Title = {Transmission latencies in a telemetry-linked brain-machine
interface.},
Journal = {Ieee Transactions on Bio Medical Engineering},
Volume = {51},
Number = {6},
Pages = {919-924},
Year = {2004},
Month = {June},
ISSN = {0018-9294},
url = {http://www.ncbi.nlm.nih.gov/pubmed/15188859},
Keywords = {bioelectric potentials;biomedical telemetry;handicapped
aids;medical computing;neurophysiology;prosthetics;},
Abstract = {To be clinically viable, a brain-machine interface (BMI)
requires transcutaneous telemetry. Spike-based compression
algorithms can be used to reduce the amount of telemetered
data, but this type of system is subject to queuing-based
transmission delays. This paper examines the relationships
between the ratio of output to average input bandwidth of an
implanted device and transmission latency and required queue
depth. The examination was performed with a computer model
designed to simulate the telemetry link. The input to the
model was presorted spike data taken from a macaque monkey
performing a motor task. The model shows that when the
output bandwidth/average input bandwidth is in unity,
significant transmission latencies occur. For a 32-neuron
system, transmitting 50 bytes of data per spike and with an
average neuron firing rate of 8.93 spikes/s, the average
maximum delay was approximately 3.2 s. It is not until the
output bandwidth is four times the average input bandwidth
that average maximum delays are reduced to less than 10 ms.
A comparison of neuron firing rate and resulting latencies
shows that high latencies result from neuron bursting. These
results will impact the design of transcutaneous telemetry
in a BMI.},
Doi = {10.1109/TBME.2004.827090},
Key = {7981869}
}
@article{fds275283,
Author = {Cohen, D and Nicolelis, MAL},
Title = {Reduction of single-neuron firing uncertainty by cortical
ensembles during motor skill learning.},
Journal = {Journal of Neuroscience},
Volume = {24},
Number = {14},
Pages = {3574-3582},
Year = {2004},
Month = {April},
url = {http://dx.doi.org/10.1523/JNEUROSCI.5361-03.2004},
Abstract = {Motor skill learning is usually characterized by shortening
of response time and performance of faster, more
stereotypical movements. However, little is known about the
changes in neural activity that underlie these behavioral
changes. Here we used chronically implanted electrode arrays
to record neuronal activity in the rat primary motor cortex
(MI) as animals learned to execute movements in two
directions. Strong modulation of MI single-neuron activity
was observed while movement duration of the animal
decreased. Despite many learning-induced changes, the
precision with which single neurons fire did not improve
with learning. Hence, prediction of movement direction from
single neurons was bounded. In contrast, prediction of
movement direction using neuronal ensembles improved
significantly with learning, suggesting that, with practice,
neuronal ensembles learn to overcome the uncertainty
introduced by single-neuron stochastic activity.},
Doi = {10.1523/JNEUROSCI.5361-03.2004},
Key = {fds275283}
}
@article{8122917,
Author = {Obeid, I and Nicolelis, MAL and Wolf, PD},
Title = {A low power multichannel analog front end for portable
neural signal recordings.},
Journal = {Journal of Neuroscience Methods},
Volume = {133},
Number = {1-2},
Pages = {27-32},
Year = {2004},
Month = {February},
ISSN = {0165-0270},
url = {http://www.ncbi.nlm.nih.gov/pubmed/14757341},
Keywords = {analogue-digital conversion;biomedical telemetry;cellular
biophysics;differential amplifiers;high-pass
filters;low-pass filters;medical signal processing;neurophysiology;noise;signal
sampling;time division multiplexing;voltage
regulators;},
Abstract = {We present the design and testing of a 16-channel analog
amplifier for processing neural signals. Each channel has
the following features: (1) variable gain (70-94 dB), (2)
four high pass Bessel filter poles (f(-3 dB)=445 Hz), (3)
five low pass Bessel filter poles (f(-3 dB)=6.6 kHz), and
(4) differential amplification with a user selectable
reference channel to reject common mode background
biological noise. Processed signals are time division
multiplexed and sampled by an on-board 12-bit analog to
digital converter at up to 62.5k samples/s per channel. The
board is powered by two low dropout voltage regulators which
may be supplied by a single battery. The board measures 8.1
cm x 9.9 cm, weighs 50 g, and consumes up to 130 mW. Its low
input-referred noise (1.0 microV(RMS)) makes it possible to
process low amplitude neural signals; the board was
successfully tested in vivo to process cortically derived
extracellular action potentials in primates. Signals
processed by this board were compared to those generated by
a commercially available system and were found to be nearly
identical. Background noise generated by mastication was
substantially attenuated by the selectable reference
circuit. The described circuit is light weight and low power
and is used as a component of a wearable multichannel neural
telemetry system.},
Doi = {10.1016/j.jneumeth.2003.09.024},
Key = {8122917}
}
@article{8114248,
Author = {Obeid, I and Nicolelis, MAL and Wolf, PD},
Title = {A multichannel telemetry system for single unit neural
recordings.},
Journal = {Journal of Neuroscience Methods},
Volume = {133},
Number = {1-2},
Pages = {33-38},
Year = {2004},
Month = {February},
ISSN = {0165-0270},
url = {http://www.ncbi.nlm.nih.gov/pubmed/14757342},
Keywords = {bioelectric potentials;biomedical electrodes;biomedical
telemetry;cells (electric);local area networks;medical
signal processing;microcomputers;neurophysiology;signal
sampling;system buses;},
Abstract = {We present the design, testing, and evaluation of a 16
channel wearable telemetry system to facilitate multichannel
single unit recordings from freely moving test subjects. Our
design is comprised of (1) a 16-channel analog front end
board to condition and sample signals derived from implanted
neural electrodes, (2) a digital board for processing and
buffering the digitized waveforms, and (3) an index-card
sized 486 PC equipped with an IEEE 802.11b wireless ethernet
card. Digitized data (up to 12 bits of resolution at 31.25k
samples/s per channel) is transferred to the PC and sent to
a nearby host computer on a wireless local area network. Up
to 12 of the 16 channels were transmitted simultaneously for
sustained periods at a range of 9 m. The device measures 5.1
cm x 8.1 cm x 12.4 cm, weighs 235 g, and is powered from
rechargeable lithium ion batteries with a lifespan of 45 min
at maximum transmission power. The device was successfully
used to record signals from awake, chronically implanted
macaque and owl monkeys.},
Doi = {10.1016/j.jneumeth.2003.09.023},
Key = {8114248}
}
@article{fds275282,
Author = {Ribeiro, S and Gervasoni, D and Soares, ES and Zhou, Y and Lin, S-C and Pantoja, J and Lavine, M and Nicolelis, MAL},
Title = {Long-lasting novelty-induced neuronal reverberation during
slow-wave sleep in multiple forebrain areas.},
Journal = {Plos Biology},
Volume = {2},
Number = {1},
Pages = {E24},
Year = {2004},
Month = {January},
url = {http://dx.doi.org/10.1371/journal.pbio.0020024},
Abstract = {The discovery of experience-dependent brain reactivation
during both slow-wave (SW) and rapid eye-movement (REM)
sleep led to the notion that the consolidation of recently
acquired memory traces requires neural replay during sleep.
To date, however, several observations continue to undermine
this hypothesis. To address some of these objections, we
investigated the effects of a transient novel experience on
the long-term evolution of ongoing neuronal activity in the
rat forebrain. We observed that spatiotemporal patterns of
neuronal ensemble activity originally produced by the
tactile exploration of novel objects recurred for up to 48 h
in the cerebral cortex, hippocampus, putamen, and thalamus.
This novelty-induced recurrence was characterized by low but
significant correlations values. Nearly identical results
were found for neuronal activity sampled when animals were
moving between objects without touching them. In contrast,
negligible recurrence was observed for neuronal patterns
obtained when animals explored a familiar environment. While
the reverberation of past patterns of neuronal activity was
strongest during SW sleep, waking was correlated with a
decrease of neuronal reverberation. REM sleep showed more
variable results across animals. In contrast with data from
hippocampal place cells, we found no evidence of time
compression or expansion of neuronal reverberation in any of
the sampled forebrain areas. Our results indicate that
persistent experience-dependent neuronal reverberation is a
general property of multiple forebrain structures. It does
not consist of an exact replay of previous activity, but
instead it defines a mild and consistent bias towards
salient neural ensemble firing patterns. These results are
compatible with a slow and progressive process of memory
consolidation, reflecting novelty-related neuronal ensemble
relationships that seem to be context- rather than
stimulus-specific. Based on our current and previous
results, we propose that the two major phases of sleep play
distinct and complementary roles in memory consolidation:
pretranscriptional recall during SW sleep and
transcriptional storage during REM sleep.},
Doi = {10.1371/journal.pbio.0020024},
Key = {fds275282}
}
@article{8255493,
Author = {Sanchez, JC and Principe, JC and Carmena, JM and Lebedev, MA and Nicolelis, MAL},
Title = {Simultaneus prediction of four kinematic variables for a
brain-machine interface using a single recurrent neural
network.},
Journal = {Conference Proceedings : ... Annual International Conference
of the Ieee Engineering in Medicine and Biology Society.
Ieee Engineering in Medicine and Biology Society. Annual
Conference},
Volume = {2004},
Pages = {5321-5324},
Address = {San Francisco, CA, USA},
Year = {2004},
ISSN = {0589-1019},
url = {http://dx.doi.org/10.1109/IEMBS.2004.1404486},
Keywords = {biomechanics;brain;cellular biophysics;kinematics;medical
signal processing;neurophysiology;prosthetics;recurrent
neural nets;user interfaces;},
Abstract = {Implementation of brain-machine interface neural-to-motor
mapping algorithms in low-power, portable digital signal
processors (DSPs) requires efficient use of model resources
especially when predicting signals that show
interdependencies. We show here that a single recurrent
neural network can simultaneously predict hand position and
velocity from the same ensemble of cells using a minimalist
topology. Analysis of the trained topology showed that the
model learns to concurrently represent multiple kinematic
parameters in a single state variable. We further assess the
expressive power of the state variables for both large and
small topologies.},
Doi = {10.1109/IEMBS.2004.1404486},
Key = {8255493}
}
@article{fds275285,
Author = {Wessberg, J and Nicolelis, MAL},
Title = {Optimizing a linear algorithm for real-time robotic control
using chronic cortical ensemble recordings in
monkeys.},
Journal = {Journal of Cognitive Neuroscience},
Volume = {16},
Number = {6},
Pages = {1022-1035},
Year = {2004},
ISSN = {0898-929X},
url = {http://dx.doi.org/10.1162/0898929041502652},
Abstract = {Previous work in our laboratory has demonstrated that a
simple linear model can be used to translate cortical
neuronal activity into real-time motor control commands that
allow a robot arm to mimic the intended hand movements of
trained primates. Here, we describe the results of a
comprehensive analysis of the contribution of single
cortical neurons to this linear model. Key to the operation
of this model was the observation that a large percentage of
cortical neurons located in both frontal and parietal
cortical areas are tuned for hand position. In most neurons,
hand position tuning was time-dependent, varying
continuously during a 1-sec period before hand movement
onset. The relevance of this physiological finding was
demonstrated by showing that maximum contribution of
individual neurons to the linear model was only achieved
when optimal parameters for the impulse response functions
describing time-varying neuronal position tuning were
selected. Optimal parameters included impulse response
functions with 1.0- to 1.4-sec time length and 50- to
100-msec bins. Although reliable generalization and
long-term predictions (60-90 min) could be achieved after
10-min training sessions, we noticed that the model
performance degraded over long periods. Part of this
degradation was accounted by the observation that neuronal
position tuning varied significantly throughout the duration
(60-90 min) of a recording session. Altogether, these
results indicate that the experimental paradigm described
here may be useful not only to investigate aspects of neural
population coding, but it may also provide a test bed for
the development of clinically useful cortical prosthetic
devices aimed at restoring motor functions in severely
paralyzed patients.},
Doi = {10.1162/0898929041502652},
Key = {fds275285}
}
@article{fds275286,
Author = {Ribeiro, S and Nicolelis, MAL},
Title = {Reverberation, storage, and postsynaptic propagation of
memories during sleep.},
Journal = {Learning & Memory (Cold Spring Harbor, N.Y.)},
Volume = {11},
Number = {6},
Pages = {686-696},
Year = {2004},
url = {http://dx.doi.org/10.1101/lm.75604},
Abstract = {In mammals and birds, long episodes of nondreaming sleep
("slow-wave" sleep, SW) are followed by short episodes of
dreaming sleep ("rapid-eye-movement" sleep, REM). Both SW
and REM sleep have been shown to be important for the
consolidation of newly acquired memories, but the underlying
mechanisms remain elusive. Here we review
electrophysiological and molecular data suggesting that SW
and REM sleep play distinct and complementary roles on
memory consolidation: While postacquisition neuronal
reverberation depends mainly on SW sleep episodes,
transcriptional events able to promote long-lasting memory
storage are only triggered during ensuing REM sleep. We also
discuss evidence that the wake-sleep cycle promotes a
postsynaptic propagation of memory traces away from the
neural sites responsible for initial encoding. Taken
together, our results suggest that basic molecular and
cellular mechanisms underlie the reverberation, storage, and
propagation of memory traces during sleep. We propose that
these three processes alone may account for several
important properties of memory consolidation over time, such
as deeper memory encoding within the cerebral cortex,
incremental learning several nights after memory
acquisition, and progressive hippocampal
disengagement.},
Doi = {10.1101/lm.75604},
Key = {fds275286}
}
@article{7907118,
Author = {Darmanjian, S and Kim, SP and Nechyba, MC and Morrison, S and Principe,
J and Wessberg, J and Nicolelis, MAL},
Title = {Bimodal Brain-Machine Interface for Motor Control of Robotic
Prosthetic},
Journal = {Ieee International Conference on Intelligent Robots and
Systems},
Volume = {4},
Pages = {3612-3617},
Address = {Las Vegas, NV, USA},
Year = {2003},
Month = {December},
url = {http://dx.doi.org/10.1109/IROS.2003.1249716},
Keywords = {biocontrol;bioelectric potentials;hidden Markov
models;medical robotics;neural nets;neurophysiology;prosthetics;user
interfaces;},
Abstract = {We are working on mapping multi-channel neural spike data,
recorded from multiple cortical areas of an owl monkey, to
corresponding 3d monkey arm positions. In earlier work on
this mapping task, we observed that continuous function
approximators (such as artificial neural networks) have
difficulty in jointly estimating 3d arm positions for two
distinct cases - namely, when the monkey's arm is stationary
and when it is moving. Therefore, we propose a
multiple-model approach that first classifies neural spike
data into two classes, corresponding to two states of the
moneky's arm: (1) stationary and (2) moving. Then, the
output of this classifier is used as a gating mechanism for
subsequent continuous models, with one model per class. In
this paper, we first motivate and discuss our approach.
Next, we present encouraging results far the classifier
stage, based on hidden Markov models (HMMs), and also for
the entire bimodal mapping system. Finally, we conclude with
a discussion of the results and suggest future avenues of
research.},
Key = {7907118}
}
@article{7994145,
Author = {Sanchez, JC and Erdogmus, D and Rao, Y and Kim, SP and Nicolelis, M and Wessberg, J and Principe, JC},
Title = {Interpreting Neural Activity Through Linear and Nonlinear
Models for Brain Machine Interfaces},
Journal = {Annual International Conference of the Ieee Engineering in
Medicine and Biology Proceedings},
Volume = {3},
Pages = {2160-2163},
Address = {Cancun, Mexico},
Year = {2003},
Month = {December},
ISSN = {0589-1019},
url = {http://dx.doi.org/10.1109/IEMBS.2003.1280168},
Keywords = {brain;feedforward neural nets;neurophysiology;physiological
models;},
Abstract = {Brain machine interface (BMI) design can be achieved by
training linear and nonlinear models with simultaneously
recorded cortical neural activity and behavior (typically
the hand position of a primate). We propose the use of
optimized BMI models for analyzing neural activity to assess
the role of individual neurons and cortical areas in
generating the performed movement. Two models
(linear-feedforward and nonlinear-feedback) are trained to
predict the hand position of a primate from neural
recordings in a reaching task. Qualitative and quantitative
investigation of the effect of neurons and their
corresponding cortical areas through both models yields
conclusions consistent with neurophysiologic knowledge. In
addition, this analysis revealed the role of these areas and
the importance of the neurons in terms of BMI
design.},
Key = {7994145}
}
@article{fds275389,
Author = {Carmena, JM and Lebedev, MA and Crist, RE and O'Doherty, JE and Santucci, DM and Dimitrov, DF and Patil, PG and Henriquez, CS and Nicolelis, MAL},
Title = {Learning to control a brain-machine interface for reaching
and grasping by primates.},
Journal = {Plos Biology},
Volume = {1},
Number = {2},
Pages = {E42},
Year = {2003},
Month = {November},
ISSN = {1545-7885},
url = {http://www.ncbi.nlm.nih.gov/pubmed/14624244},
Keywords = {Animals • Arm • Artificial Intelligence •
Behavior, Animal • Biomechanics* • Biophysics*
• Brain • Brain Mapping • Electromyography
• Electrophysiology • Female • Hand •
Hand Strength* • Learning • Macaca • Models,
Neurological • Models, Statistical • Models,
Theoretical • Motor Activity • Motor Cortex •
Movement • Neurons • Primates • Psychomotor
Performance • Robotics • Somatosensory Cortex
• Space Perception • Time Factors •
metabolism • methods • pathology • pathology*
• physiology*},
Abstract = {Reaching and grasping in primates depend on the coordination
of neural activity in large frontoparietal ensembles. Here
we demonstrate that primates can learn to reach and grasp
virtual objects by controlling a robot arm through a
closed-loop brain-machine interface (BMIc) that uses
multiple mathematical models to extract several motor
parameters (i.e., hand position, velocity, gripping force,
and the EMGs of multiple arm muscles) from the electrical
activity of frontoparietal neuronal ensembles. As single
neurons typically contribute to the encoding of several
motor parameters, we observed that high BMIc accuracy
required recording from large neuronal ensembles. Continuous
BMIc operation by monkeys led to significant improvements in
both model predictions and behavioral performance. Using
visual feedback, monkeys succeeded in producing robot
reach-and-grasp movements even when their arms did not move.
Learning to operate the BMIc was paralleled by functional
reorganization in multiple cortical areas, suggesting that
the dynamic properties of the BMIc were incorporated into
motor and sensory cortical representations.},
Doi = {10.1371/journal.pbio.0000042},
Key = {fds275389}
}
@article{7838731,
Author = {Kim, SP and Sanchez, JC and Erdogmus, D and Rao, YN and Principe, JC and Nicolelis, M},
Title = {Modeling the Relation from Motor Cortical Neuronal Firing to
Hand Movements Using Competitive Linear Filters and a
MLP},
Journal = {Proceedings of the International Joint Conference on Neural
Networks},
Volume = {1},
Pages = {66-70},
Address = {Portland, OR, USA},
Year = {2003},
Month = {September},
url = {http://dx.doi.org/10.1109/IJCNN.2003.1223293},
Keywords = {biomechanics;brain models;handicapped aids;multilayer
perceptrons;neuromuscular stimulation;position
control;Wiener filters;},
Abstract = {Recent research has demonstrated that linear models are able
to estimate hand positions using populations of action
potentials collected in the pre-motor and motor cortical
areas of a primate's brain. One of the applications of this
result is to restore movement in patients suffering from
paralysis. To implement this technology in real-time,
reliable and accurate signal processing models that produce
sufficiently small error in the estimated hand positions are
required. In this paper, we propose the hybrid model
approach that combines competitive linear filters with a
neural network. The mapping performance of our approach is
compared with a single Wiener filter during reaching
movements. Our approach demonstrates more accurate
estimations.},
Key = {7838731}
}
@article{fds275386,
Author = {Nicolelis, MAL and Dimitrov, D and Carmena, JM and Crist, R and Lehew,
G and Kralik, JD and Wise, SP},
Title = {Chronic, multisite, multielectrode recordings in macaque
monkeys.},
Journal = {Proceedings of the National Academy of Sciences of the
United States of America},
Volume = {100},
Number = {19},
Pages = {11041-11046},
Year = {2003},
Month = {September},
ISSN = {0027-8424},
url = {http://www.ncbi.nlm.nih.gov/pubmed/12960378},
Keywords = {Action Potentials • Animals • Cerebral Cortex
• Electrodes • Female • Macaca mulatta •
Male • physiology*},
Abstract = {A paradigm is described for recording the activity of single
cortical neurons from awake, behaving macaque monkeys. Its
unique features include high-density microwire arrays and
multichannel instrumentation. Three adult rhesus monkeys
received microwire array implants, totaling 96-704
microwires per subject, in up to five cortical areas,
sometimes bilaterally. Recordings 3-4 weeks after
implantation yielded 421 single neurons with a mean
peak-to-peak voltage of 115 +/- 3 microV and a
signal-to-noise ratio of better than 5:1. As many as 247
cortical neurons were recorded in one session, and at least
58 neurons were isolated from one subject 18 months after
implantation. This method should benefit neurophysiological
investigation of learning, perception, and sensorimotor
integration in primates and the development of
neuroprosthetic devices.},
Doi = {10.1073/pnas.1934665100},
Key = {fds275386}
}
@article{fds275387,
Author = {Wiest, MC and Nicolelis, MAL},
Title = {Behavioral detection of tactile stimuli during 7-12 Hz
cortical oscillations in awake rats.},
Journal = {Nature Neuroscience},
Volume = {6},
Number = {9},
Pages = {913-914},
Year = {2003},
Month = {September},
ISSN = {1097-6256},
url = {http://www.ncbi.nlm.nih.gov/pubmed/12897789},
Keywords = {Animals • Behavior, Animal • Biological Clocks
• Cerebral Cortex • Female • Immobilization
• Physical Stimulation • Rats • Rats,
Long-Evans • Reaction Time • Touch •
Vibrissae • Wakefulness • methods •
physiology • physiology*},
Abstract = {Prominent 7-12 Hz oscillations in the primary somatosensory
cortex (S1) of awake but immobile rats might represent a
seizure-like state in which neuronal burst firing renders
animals unresponsive to incoming tactile stimuli; others
have proposed that these oscillations are analogous to human
mu rhythm. To test whether rats can respond to tactile
stimuli during 7-12 Hz oscillatory activity, we trained
head-immobilized awake animals to indicate whether they
could detect the occurrence of transient whisker deflections
while we recorded local field potentials (LFPs) from
microelectrode arrays implanted bilaterally in the S1
whisker representation area. They responded rapidly and
reliably, suggesting that this brain rhythm represents
normal physiological activity that does not preclude
perception.},
Doi = {10.1038/nn1107},
Key = {fds275387}
}
@article{fds275388,
Author = {Matell, MS and Meck, WH and Nicolelis, MAL},
Title = {Interval timing and the encoding of signal duration by
ensembles of cortical and striatal neurons.},
Journal = {Behavioral Neuroscience},
Volume = {117},
Number = {4},
Pages = {760-773},
Year = {2003},
Month = {August},
ISSN = {0735-7044},
url = {http://www.ncbi.nlm.nih.gov/pubmed/12931961},
Keywords = {Animals • Cerebral Cortex • Conditioning, Operant
• Corpus Striatum • Discrimination Learning*
• Male • Neurons • Rats • Rats,
Sprague-Dawley • Time Perception* • physiology
• physiology*},
Abstract = {This study investigated the firing patterns of striatal and
cortical neurons in rats in a temporal generalization task.
Striatal and cortical ensembles were recorded in rats
trained to lever press at 2 possible criterion durations (10
s or 40 s from tone onset). Twenty-two percent of striatal
and 15% of cortical cells had temporally specific
modulations in their firing rate, firing at a significantly
different rate around 10 s compared with 40 s. On 80% of
trials, a post hoc analysis of the trial-by-trial
consistency of the firing rates of an ensemble of neurons
predicted whether a spike train came from a time window
around 10 s versus around 40 s. Results suggest that
striatal and cortical neurons encode specific durations in
their firing rate and thereby serve as components of a
neural circuit used to represent duration.},
Doi = {10.1037/0735-7044.117.4.760},
Key = {fds275388}
}
@article{fds275390,
Author = {Nicolelis, MAL},
Title = {Brain-machine interfaces to restore motor function and probe
neural circuits.},
Journal = {Nature Reviews. Neuroscience},
Volume = {4},
Number = {5},
Pages = {417-422},
Year = {2003},
Month = {May},
ISSN = {1471-003X},
url = {http://www.ncbi.nlm.nih.gov/pubmed/12728268},
Keywords = {Animals • Humans • Motor Activity • Motor
Cortex • Nerve Net • Neuronal Plasticity •
Paralysis • Prostheses and Implants* • pathology
• physiology • physiology* •
therapy},
Language = {eng},
Doi = {10.1038/nrn1105},
Key = {fds275390}
}
@article{fds275396,
Author = {Obeid, I and Morizio, JC and Moxon, KA and Nicolelis, MAL and Wolf,
PD},
Title = {Two multichannel integrated circuits for neural recording
and signal processing.},
Journal = {Ieee Transactions on Bio Medical Engineering},
Volume = {50},
Number = {2},
Pages = {255-258},
Year = {2003},
Month = {February},
ISSN = {0018-9294},
url = {http://www.ncbi.nlm.nih.gov/pubmed/12665041},
Keywords = {Action Potentials • Amplifiers* • Animals •
Artifacts • Electrodes, Implanted •
Electrophysiology • Equipment Design • Feasibility
Studies • Haplorhini • Miniaturization •
Neurons • Pilot Projects • Quality Control •
Rats • Semiconductors • Somatosensory Cortex
• instrumentation* • physiology •
physiology*},
Abstract = {We have developed, manufactured, and tested two analog CMOS
integrated circuit "neurochips" for recording from arrays of
densely packed neural electrodes. Device A is a 16-channel
buffer consisting of parallel noninverting amplifiers with a
gain of 2 V/V. Device B is a 16-channel two-stage analog
signal processor with differential amplification and
high-pass filtering. It features selectable gains of 250 and
500 V/V as well as reference channel selection. The
resulting amplifiers on Device A had a mean gain of 1.99 V/V
with an equivalent input noise of 10 microV(rms). Those on
Device B had mean gains of 53.4 and 47.4 dB with a high-pass
filter pole at 211 Hz and an equivalent input noise of 4.4
microV(rms). Both devices were tested in vivo with electrode
arrays implanted in the somatosensory cortex.},
Doi = {10.1109/TBME.2002.807643},
Key = {fds275396}
}
@article{7797886,
Author = {Sanchez, JC and Erdogmus, D and Rao, Y and Principe, JC and Nicolelis,
M and Wessberg, J},
Title = {Learning the contributions of the motor, premotor, and
posterior parietal cortices for hand trajectory
reconstruction in a brain machine interface},
Journal = {International Ieee/Embs Conference on Neural Engineering,
Ner},
Volume = {2003-January},
Pages = {59-62},
Publisher = {IEEE},
Address = {Capri Island, Italy},
Year = {2003},
Month = {January},
ISSN = {1948-3546},
url = {http://dx.doi.org/10.1109/CNE.2003.1196755},
Keywords = {multilayer perceptrons;recurrent neural nets;signal
processing;user interfaces;},
Abstract = {The ability to record, in real-time, the activity of
hundreds of cortical neurons gives the ability to
selectively study the function of clusters of cortical
neurons in Brain Machine Interface (BMI) experiments. We
have demonstrated using a recursive multilayer perceptron
(RMLP) that using the appropriate signal processing theory
in a well-chosen parsimonious model, we can develop
constructs that agree with basic physiological modeling of
neural control. By looking through the trained model, we
have found interesting relationships between the neuronal
firing and the movement. The RMLP allows us to continuously
study the relationship between neural activity and behavior
without the active interference of the experimenter. The
findings presented in this study offer an opportunity for
the neuroscience community to compare the cortical
interactions as constructed by the RMLP to what is known
about motor neurophysiology.},
Doi = {10.1109/CNE.2003.1196755},
Key = {7797886}
}
@article{7843967,
Author = {Kim, S-P and Sanchez, JC and Erdogmus, D and Rao, YN and Wessberg, J and Principe, JC and Nicolelis, M},
Title = {Divide-and-conquer approach for brain machine interfaces:
nonlinear mixture of competitive linear models.},
Journal = {Neural Networks : the Official Journal of the International
Neural Network Society},
Volume = {16},
Number = {5-6},
Pages = {865-871},
Year = {2003},
url = {http://dx.doi.org/10.1016/S0893-6080(03)00108-4},
Keywords = {brain models;delays;divide and conquer methods;learning
(artificial intelligence);least mean squares
methods;man-machine systems;multilayer perceptrons;nonlinear
network analysis;user interfaces;},
Abstract = {This paper proposes a divide-and-conquer strategy for
designing brain machine interfaces. A nonlinear combination
of competitively trained local linear models (experts) is
used to identify the mapping from neuronal activity in
cortical areas associated with arm movement to the hand
position of a primate. The proposed architecture and the
training algorithm are described in detail and numerical
performance comparisons with alternative linear and
nonlinear modeling approaches, including time-delay neural
networks and recursive multilayer perceptrons, are
presented. This new strategy allows training the local
linear models using normalized LMS and using a relatively
smaller nonlinear network to efficiently combine the
predictions of the linear experts. This leads to savings in
computational requirements, while the performance is still
similar to a large fully nonlinear network.},
Doi = {10.1016/S0893-6080(03)00108-4},
Key = {7843967}
}
@article{fds275421,
Author = {Nicolelis, MAL and Fanselow, EE},
Title = {Dynamic shifting in thalamocortical processing during
different behavioural states.},
Journal = {Philosophical Transactions of the Royal Society of London.
Series B, Biological Sciences},
Volume = {357},
Number = {1428},
Pages = {1753-1758},
Year = {2002},
Month = {December},
ISSN = {0962-8436},
url = {http://www.ncbi.nlm.nih.gov/pubmed/12626009},
Keywords = {Animals • Behavior, Animal • Cerebral Cortex
• Models, Neurological • Neural Pathways •
Rats • Thalamus • physiology •
physiology*},
Abstract = {Recent experiments in our laboratory have indicated that as
rats shift the behavioural strategy employed to explore
their surrounding environment, there is a parallel change in
the physiological properties of the neuronal ensembles that
define the main thalamocortical loop of the trigeminal
somatosensory system. Based on experimental evidence from
several laboratories, we propose that this concurrent shift
in behavioural strategy and thalamocortical physiological
properties provides rats with an efficient way to optimize
either the detection or analysis of complex tactile
stimuli.},
Doi = {10.1098/rstb.2002.1175},
Key = {fds275421}
}
@article{7748470,
Author = {Won, DS and Obeid, I and Morizio, JC and Nicolelis, MAL and Wolf,
PD},
Title = {A multichannel CMOS analog front end IC for neural
recordings},
Journal = {Annual International Conference of the Ieee Engineering in
Medicine and Biology Proceedings},
Volume = {3},
Pages = {2070-2071},
Publisher = {IEEE},
Address = {Houston, TX, USA},
Year = {2002},
Month = {December},
url = {http://dx.doi.org/10.1109/IEMBS.2002.1053172},
Keywords = {bioelectric potentials;CMOS analogue integrated
circuits;high-pass filters;low-pass filters;neurophysiology;prosthetics;},
Abstract = {A multichannel integrated circuit for processing
extracellular neural signals has been designed and
manufactured. The analog CMOS IC consists of 17 parallel
channels, each comprised of three cascaded stages: bandpass
filter with gain, switched capacitor filters, and output
buffer with selectable gain. The bandpass filter stage
features an opamp with non-inverting resistor feedback and
an off-chip capacitor in the feedback pathway to provide
gain (43dB) and one high pass filter pole (220Hz). The low
pass pole is set by the gain-bandwidth product of the opamp.
In the switched capacitor filter stage, a one-pole high pass
filter (500Hz) cascades into a two-pole biquadratic low pass
filter (5kHz). The switched capacitor filters may be
controlled by either an on-board tunable ring oscillator
centered at 50kHz or an off-chip clock. A four-phase clock
splitter provides the necessary filter control-signals; a
phase delay of 180° between the high and low pass clock
lines maximizes settling time between the filters. The
output buffer stage provides selectable gain at 20dB or
32dB. The IC was manufactured by AMI using a 0.5μm triple
metal double poly process, and measures 4.2 × 3.8 mm. The
die is designed to be packaged in a flip-chip
sub-assembly.},
Doi = {10.1109/iembs.2002.1053172},
Key = {7748470}
}
@article{fds275458,
Author = {Nicolelis, MAL},
Title = {The amazing adventures of robotrat.},
Journal = {Trends Cogn Sci},
Volume = {6},
Number = {11},
Pages = {449-450},
Year = {2002},
Month = {November},
ISSN = {1879-307X},
url = {http://www.ncbi.nlm.nih.gov/pubmed/12457887},
Abstract = {By using electrical brain stimulation to deliver both
'virtual' tactile cues and rewards to freely roaming rats,
Talwar et al. have been able to instruct animals remotely to
navigate through complex mazes and natural environments they
have never visited before. These results provide both an
elegant alternative way to train animals and a new approach
to study basic neurophysiological principles of animal
navigation.},
Language = {ENG},
Doi = {10.1016/s1364-6613(02)01991-5},
Key = {fds275458}
}
@article{fds275426,
Author = {Nicolelis, MAL and Chapin, JK},
Title = {Controlling robots with the mind.},
Journal = {Scientific American},
Volume = {287},
Number = {4},
Pages = {46-53},
Year = {2002},
Month = {October},
ISSN = {0036-8733},
url = {http://www.ncbi.nlm.nih.gov/pubmed/12271524},
Keywords = {Action Potentials • Animals • Aotidae • Brain
• Electrodes, Implanted • Electronics •
Electrophysiology • Female • Miniaturization
• Motor Cortex • Motor Neurons • Nervous
System Diseases • Paralysis • Prostheses and
Implants • Rats • Robotics • instrumentation*
• physiology • physiology* •
therapy},
Language = {eng},
Doi = {10.1038/scientificamerican1002-46},
Key = {fds275426}
}
@article{fds275429,
Author = {Nicolelis, MAL and Ribeiro, S},
Title = {Multielectrode recordings: the next steps.},
Journal = {Current Opinion in Neurobiology},
Volume = {12},
Number = {5},
Pages = {602-606},
Year = {2002},
Month = {October},
ISSN = {0959-4388},
url = {http://www.ncbi.nlm.nih.gov/pubmed/12367642},
Keywords = {Animals • Electrodes • Electrophysiology •
Nervous System Physiological Phenomena* • Neurons
• methods* • physiology},
Abstract = {At present, a growing number of laboratories are acquiring
the capability of simultaneously monitoring the
extracellular activity of over a hundred single neurons in
both anaesthetized and awake animals. This paradigm, known
as multielectrode recordings, is changing the face of
systems neuroscience by allowing, for the first time, the
visualization of the function of entire neural circuits at
work. Current methods of multielectrode recording employ
state of the art technologies; two potential new avenues of
research will likely emerge from the further development of
these experimental paradigms.},
Language = {eng},
Doi = {10.1016/s0959-4388(02)00374-4},
Key = {fds275429}
}
@article{fds275462,
Author = {Katz, DB and Nicolelis, MAL and Simon, SA},
Title = {Gustatory processing is dynamic and distributed.},
Journal = {Current Opinion in Neurobiology},
Volume = {12},
Number = {4},
Pages = {448-454},
Year = {2002},
Month = {August},
ISSN = {0959-4388},
url = {http://www.ncbi.nlm.nih.gov/pubmed/12139994},
Keywords = {Action Potentials • Amygdala • Animals •
Brain • Brain Stem • Cerebral Cortex •
Hypothalamus • Models, Neurological • Neural
Pathways • Somatosensory Cortex • Taste •
Taste Buds • Thalamus • Time Factors •
anatomy & histology • physiology •
physiology*},
Abstract = {The process of gustatory coding consists of neural responses
that provide information about the quantity and quality of
food, its generalized sensation, its hedonic value, and
whether it should be swallowed. Many of the models presently
used to analyze gustatory signals are static in that they
use the average neural firing rate as a measure of activity
and are unimodal in the sense they are thought to only
involve chemosensory information. We have recently
elaborated upon a dynamic model of gustatory coding that
involves interactions between neurons in single as well as
in spatially separate, gustatory and somatosensory regions.
We propose that the specifics of gustatory responses grow
not only out of information ascending from taste receptor
cells, but also from the cycling of information around a
massively interconnected system.},
Language = {eng},
Doi = {10.1016/s0959-4388(02)00341-0},
Key = {fds275462}
}
@article{7401953,
Author = {Hugh, GS and Laubach, M and Nicolelis, MAL and Henriquez,
CS},
Title = {A simulator for the analysis of neuronal ensemble activity:
Application to reaching tasks},
Journal = {Neurocomputing},
Volume = {44-46},
Pages = {847-854},
Publisher = {Elsevier BV},
Address = {Monterey, CA, USA},
Year = {2002},
Month = {July},
ISSN = {0925-2312},
url = {http://dx.doi.org/10.1016/S0925-2312(02)00482-4},
Keywords = {bioelectric potentials;brain models;neural
nets;neuromuscular stimulation;},
Abstract = {A biologically based, multi-cortical computational model was
developed to investigate how ensembles of neurons learn to
execute a three-dimensional reaching task. The model
produces outputs of spike trains that can be analyzed using
a variety of multivariate analysis tools. Simulations show
that after learning, the model neurons exhibit broad
directional tuning that depend on the defined muscle
directions of the simulated arm, and that these neurons form
functional clusters within cortical areas. The utility of
the model is demonstrated by testing arm movement prediction
strategies using ensemble activity. © 2002 Published by
Elsevier Science B.V.},
Doi = {10.1016/S0925-2312(02)00482-4},
Key = {7401953}
}
@article{fds275430,
Author = {Nicolelis, MAL and Fanselow, EE},
Title = {Thalamocortical [correction of Thalamcortical] optimization
of tactile processing according to behavioral
state.},
Journal = {Nature Neuroscience},
Volume = {5},
Number = {6},
Pages = {517-523},
Year = {2002},
Month = {June},
ISSN = {1097-6256},
url = {http://www.ncbi.nlm.nih.gov/pubmed/12037519},
Keywords = {Afferent Pathways • Animals • Behavior, Animal
• Efferent Pathways • Models, Neurological •
Rats • Somatosensory Cortex • Thalamus •
Touch • physiology • physiology*},
Abstract = {We propose a conceptual model that describes the operation
of the main thalamocortical loop of the rat somatosensory
system. According to this model, the asynchronous
convergence of ascending and descending projections
dynamically alters the physiological properties of thalamic
neurons in the ventral posterior medial (VPM) nucleus as
rats shift between three behavioral states. Two of these
states are characterized by distinct modes of rhythmic
whisker movements. We posit that these simultaneous shifts
in exploratory behavioral strategy and in the physiological
properties of VPM neurons allow rats to either (i) optimize
the detection of stimuli that are novel or difficult to
sense or (ii) process complex patterns of multi-whisker
stimulation.},
Language = {eng},
Doi = {10.1038/nn0602-517},
Key = {fds275430}
}
@article{fds275461,
Author = {Nicolelis, MAL},
Title = {Depression at thalamocortical synapses: the key for cortical
neuronal adaptation?},
Journal = {Neuron},
Volume = {34},
Number = {3},
Pages = {331-332},
Year = {2002},
Month = {April},
ISSN = {0896-6273},
url = {http://www.ncbi.nlm.nih.gov/pubmed/11988163},
Keywords = {Adaptation, Physiological • Animals • Cerebral
Cortex • Neuronal Plasticity* • Rats •
Synapses • Synaptic Transmission • Thalamus •
Touch • cytology • metabolism* •
physiology*},
Abstract = {Neuronal adaptation to repetitive sensory stimuli is
ubiquitous in the mammalian cortex. Despite its prevalence,
the cellular mechanisms underlying this basic physiological
property remain a matter of dispute. In this issue of
Neuron, Chung et al. provide conclusive evidence that
depression of thalamocortical synapses may play a
significant role in the expression of neuronal adaptation in
the rat somatosensory cortex.},
Language = {eng},
Doi = {10.1016/s0896-6273(02)00691-8},
Key = {fds275461}
}
@article{fds275454,
Author = {Katz, DB and Simon, SA and Nicolelis, MAL},
Title = {Taste-specific neuronal ensembles in the gustatory cortex of
awake rats.},
Journal = {Journal of Neuroscience},
Volume = {22},
Number = {5},
Pages = {1850-1857},
Year = {2002},
Month = {March},
ISSN = {1529-2401},
url = {http://www.ncbi.nlm.nih.gov/pubmed/11880514},
Keywords = {Action Potentials • Animals • Cerebral Cortex
• Citric Acid • Electrodes, Implanted •
Electrophysiology • Female • Male • Neurons
• Nicotine • Quinine • Rats • Rats,
Long-Evans • Reaction Time • Sodium Chloride
• Statistics as Topic • Stimulation, Chemical
• Sucrose • Taste • Tongue • Wakefulness
• cytology • drug effects • pharmacology
• physiology • physiology*},
Abstract = {In gustatory cortex, single-neuron activity reflects the
multimodal processing of taste stimuli. Little is known,
however, about the interactions between gustatory cortical
(GC) neurons during tastant processing. Here, these
interactions were characterized. It was found that 36% (85
of 237) of neuron pairs, including many (61%) in which one
or both single units were not taste specific, produced
significant cross-correlations (CCs) to a subset of tastants
across a hundreds of milliseconds timescale. Significant CCs
arose from the coupling between the firing rates of neurons
as those rates changed through time. Such coupling
significantly increased the amount of tastant-specific
information contained in ensembles. These data suggest that
taste-specific GC assemblies may transiently form and
coevolve on a behaviorally appropriate timescale,
contributing to rats' ability to discriminate
tastants.},
Language = {eng},
Doi = {10.1523/JNEUROSCI.22-05-01850.2002},
Key = {fds275454}
}
@article{fds275279,
Author = {Nicolelis, MAL and Fanselow, EE},
Title = {Erratum: Thalamcortical optimization of tactile processing
according to behavioral state (Nature Neuroscience (2002) 5
(517-523))},
Journal = {Nature Neuroscience},
Volume = {5},
Number = {7},
Pages = {704},
Publisher = {Springer Science and Business Media LLC},
Year = {2002},
Month = {January},
url = {http://dx.doi.org/10.1038/nn0702-704a},
Doi = {10.1038/nn0702-704a},
Key = {fds275279}
}
@article{fds275460,
Author = {Shuler, MG and Krupa, DJ and Nicolelis, MAL},
Title = {Integration of bilateral whisker stimuli in rats: role of
the whisker barrel cortices.},
Journal = {Cerebral Cortex (New York, N.Y. : 1991)},
Volume = {12},
Number = {1},
Pages = {86-97},
Year = {2002},
Month = {January},
ISSN = {1047-3211},
url = {http://www.ncbi.nlm.nih.gov/pubmed/11734535},
Keywords = {Animals • Behavior, Animal • Electric Stimulation
• Electrodes, Implanted • Functional Laterality
• Male • Physical Stimulation • Psychomotor
Performance • Rats • Rats, Long-Evans •
Somatosensory Cortex • Vibrissae • innervation*
• physiology • physiology*},
Abstract = {Recently, we demonstrated that neural responses within the
whisker region of the primary somatosensory cortex (SIw) of
rats are profoundly influenced by the spatiotemporal
attributes of ipsilateral, as well as contralateral, whisker
stimuli. As inactivation of one SIw eliminates in the intact
SIw both ipsilaterally evoked responses and the influence of
ipsilateral stimulation on contralaterally evoked activity,
we proposed that interhemispheric interactions between the
SIws may be important for integrating bilateral whisker
information. To test whether rats can recognize the
bilateral nature of a whisker stimulus, we developed a
tactile discrimination task that required rats to conjointly
determine distances to a left and a right discriminandum as
equidistant or non-equidistant using only their facial
whiskers. All rats trained in this task achieved performance
levels indicative of an ability to integrate bilateral
whisker information. Testing during unilateral, as well as
bilateral, inactivation of the SIws indicated that rats rely
on both SIws for detecting the bilateral nature of a whisker
stimulus. Rats were unable to perform the task without both
sets of whiskers, a fact that indicates that the whiskers
(and not other modalities) were used to perform this task.
The findings presented here indicate that rats can solve a
task that requires the conjoint detection of left and right
whisker-mediated distance information and implicate the SIws
as central to this ability.},
Language = {eng},
Doi = {10.1093/cercor/12.1.86},
Key = {fds275460}
}
@article{fds114890,
Title = {Nicolelis MAL, Fanselow EE (2002) Dynamic shifting in
thalamocortical processing during different behavior. Phil
Trans R Soc Lond B 357: 1753-1758.},
Year = {2002},
Key = {fds114890}
}
@article{7507580,
Author = {Nicolelis, MAL and Chapin, JK},
Title = {Controlling robots with the mind},
Journal = {Sci. Am. (Int. Ed.) (Usa)},
Volume = {287},
Number = {4},
Pages = {24-31},
Year = {2002},
Keywords = {manipulator dynamics;neurophysiology;robot
dynamics;},
Abstract = {People with nerve or limb injuries may one day be able to
command wheelchairs, prosthetics and even paralyzed arms and
legs by "thinking them through" the motions},
Key = {7507580}
}
@article{fds275428,
Author = {Fanselow, EE and Sameshima, K and Baccala, LA and Nicolelis,
MA},
Title = {Thalamic bursting in rats during different awake behavioral
states.},
Journal = {Proceedings of the National Academy of Sciences of the
United States of America},
Volume = {98},
Number = {26},
Pages = {15330-15335},
Year = {2001},
Month = {December},
ISSN = {0027-8424},
url = {http://www.ncbi.nlm.nih.gov/pubmed/11752471},
Keywords = {Animals • Behavior, Animal* • Electric Stimulation
• Neurons • Rats • Thalamus •
Wakefulness* • physiology • physiology*},
Abstract = {Thalamic neurons have two firing modes: tonic and bursting.
It was originally suggested that bursting occurs only during
states such as slow-wave sleep, when little or no
information is relayed by the thalamus. However, bursting
occurs during wakefulness in the visual and somatosensory
thalamus, and could theoretically influence sensory
processing. Here we used chronically implanted electrodes to
record from the ventroposterior medial thalamic nucleus
(VPM) and primary somatosensory cortex (SI) of awake, freely
moving rats during different behaviors. These behaviors
included quiet immobility, exploratory whisking
(large-amplitude whisker movements), and whisker twitching
(small-amplitude, 7- to 12-Hz whisker movements). We
demonstrated that thalamic bursting appeared during the
oscillatory activity occurring before whisker twitching
movements, and continued throughout the whisker twitching.
Further, thalamic bursting occurred during whisker twitching
substantially more often than during the other behaviors,
and a neuron was most likely to respond to a stimulus if a
burst occurred approximately 120 ms before the stimulation.
In addition, the amount of cortical area activated was
similar to that during whisking. However, when SI was
inactivated by muscimol infusion, whisker twitching was
never observed. Finally, we used a statistical technique
called partial directed coherence to identify the direction
of influence of neural activity between VPM and SI, and
observed that there was more directional coherence from SI
to VPM during whisker twitching than during the other
behaviors. Based on these findings, we propose that during
whisker twitching, a descending signal from SI triggers
thalamic bursting that primes the thalamocortical loop for
enhanced signal detection during the whisker twitching
behavior.},
Language = {eng},
Doi = {10.1073/pnas.261273898},
Key = {fds275428}
}
@article{fds275431,
Author = {Das, A and Franca, JG and Gattass, R and Kaas, JH and Nicolelis, MA and Timo-Iaria, C and Vargas, CD and Weinberger, NM and Volchan,
E},
Title = {The brain decade in debate: VI. Sensory and motor maps:
dynamics and plasticity.},
Journal = {Brazilian Journal of Medical and Biological Research =
Revista Brasileira De Pesquisas Medicas E
Biologicas},
Volume = {34},
Number = {12},
Pages = {1497-1508},
Year = {2001},
Month = {December},
ISSN = {0100-879X},
url = {http://www.ncbi.nlm.nih.gov/pubmed/11717702},
Keywords = {Animals • Brain Mapping* • Cerebral Cortex •
Emotions • Humans • Learning • Motor Cortex
• Neuronal Plasticity • Neurons •
Somatosensory Cortex • Visual Perception •
cytology • physiology • physiology*},
Abstract = {This article is an edited transcription of a virtual
symposium promoted by the Brazilian Society of Neuroscience
and Behavior (SBNeC). Although the dynamics of sensory and
motor representations have been one of the most studied
features of the central nervous system, the actual
mechanisms of brain plasticity that underlie the dynamic
nature of sensory and motor maps are not entirely unraveled.
Our discussion began with the notion that the processing of
sensory information depends on many different cortical
areas. Some of them are arranged topographically and others
have non-topographic (analytical) properties. Besides a
sensory component, every cortical area has an efferent
output that can be mapped and can influence motor behavior.
Although new behaviors might be related to modifications of
the sensory or motor representations in a given cortical
area, they can also be the result of the acquired ability to
make new associations between specific sensory cues and
certain movements, a type of learning known as conditioning
motor learning. Many types of learning are directly related
to the emotional or cognitive context in which a new
behavior is acquired. This has been demonstrated by
paradigms in which the receptive field properties of
cortical neurons are modified when an animal is engaged in a
given discrimination task or when a triggering feature is
paired with an aversive stimulus. The role of the
cholinergic input from the nucleus basalis to the neocortex
was also highlighted as one important component of the
circuits responsible for the context-dependent changes that
can be induced in cortical maps.},
Language = {eng},
Doi = {10.1590/s0100-879x2001001200001},
Key = {fds275431}
}
@article{fds275432,
Author = {Ghazanfar, AA and Krupa, DJ and Nicolelis, MA},
Title = {Role of cortical feedback in the receptive field structure
and nonlinear response properties of somatosensory thalamic
neurons.},
Journal = {Experimental Brain Research},
Volume = {141},
Number = {1},
Pages = {88-100},
Year = {2001},
Month = {November},
ISSN = {0014-4819},
url = {http://www.ncbi.nlm.nih.gov/pubmed/11685413},
Keywords = {Animals • Feedback • Female • Neurons •
Nonlinear Dynamics • Rats • Rats, Long-Evans
• Reaction Time • Somatosensory Cortex •
Thalamus • Ventral Thalamic Nuclei • Vibrissae
• physiology • physiology*},
Abstract = {Previous studies have suggested that the descending pathway
from the primary somatosensory (SI) cortex to the ventral
posterior nucleus of the thalamus has only a mild
facilitative influence over thalamic neurons. Given the
large numbers of corticothalamic terminations within the rat
somatosensory thalamus and their complex topography, we
sought to examine the role of corticothalamic feedback in
the genesis of spatiotemporal receptive fields and the
integration of complex tactile stimuli in the thalamus. By
combining focal cortical inactivation (produced by
microinjection of the GABA(A) agonist muscimol), with
chronic multielectrode recordings, we observed that feedback
from the rat SI cortex has multiple influences on its
primary thalamic relay, the ventral posterior medial (VPM)
nucleus. Our data demonstrate that, when single-whisker
stimuli were used, the elimination of cortical feedback
caused significant changes in the spatiotemporal structure
of the receptive fields of VPM neurons. Cortical feedback
also accounted for the nonlinear summation of VPM neural
responses to simultaneously stimulated whiskers, in effect
"linearizing" the responses. These results argue that the
integration and transmission of tactile information through
VPM are strongly influenced by the state of SI
cortex.},
Language = {eng},
Doi = {10.1007/s002210100849},
Key = {fds275432}
}
@article{fds275433,
Author = {Kralik, JD and Dimitrov, DF and Krupa, DJ and Katz, DB and Cohen, D and Nicolelis, MA},
Title = {Techniques for long-term multisite neuronal ensemble
recordings in behaving animals.},
Journal = {Methods (San Diego, Calif.)},
Volume = {25},
Number = {2},
Pages = {121-150},
Year = {2001},
Month = {October},
ISSN = {1046-2023},
url = {http://www.ncbi.nlm.nih.gov/pubmed/11812202},
Keywords = {Animals • Behavior, Animal* • Brain •
Electrodes • Electrophysiology • Mice •
Multivariate Analysis • Neurology • Neurons •
Neurosurgery • Rats • Time Factors • methods*
• pathology • physiology*},
Abstract = {Advances in our understanding of neural systems will go hand
in hand with improvements in the experimental techniques
used to study these systems. This article describes a series
of methodological developments aimed at enhancing the power
of the methods needed to record simultaneously from
populations of neurons over broad regions of the brain in
awake, behaving animals. First, our laboratory has made many
advances in electrode design, including movable bundle and
array electrodes and smaller electrode assemblies. Second,
to perform longer and more complex multielectrode
implantation surgeries in primates, we have modified our
surgical procedures by employing comprehensive physiological
monitoring akin to human neuroanesthesia. We have also
developed surgical implantation techniques aimed at
minimizing brain tissue damage and facilitating penetration
of the cortical surface. Third, we have integrated new
technologies into our neural ensemble, stimulus and
behavioral recording experiments to provide more detailed
measurements of experimental variables. Finally, new data
analytical techniques are being used in the laboratory to
analyze increasingly large quantities of
data.},
Language = {eng},
Doi = {10.1006/meth.2001.1231},
Key = {fds275433}
}
@article{fds275459,
Author = {Krupa, DJ and Matell, MS and Brisben, AJ and Oliveira, LM and Nicolelis,
MA},
Title = {Behavioral properties of the trigeminal somatosensory system
in rats performing whisker-dependent tactile
discriminations.},
Journal = {Journal of Neuroscience},
Volume = {21},
Number = {15},
Pages = {5752-5763},
Year = {2001},
Month = {August},
ISSN = {1529-2401},
url = {http://www.ncbi.nlm.nih.gov/pubmed/11466447},
Keywords = {Afferent Pathways • Animals • Behavior, Animal
• Discrimination Learning • Electrodes, Implanted
• Facial Nerve • GABA Agonists • GABA-A
Receptor Agonists • Male • Mechanoreceptors •
Muscimol • Physical Stimulation • Rats •
Rats, Long-Evans • Somatosensory Cortex • Touch
• Trigeminal Nerve • Vibrissae •
administration & dosage • drug effects •
innervation • instrumentation • pharmacology
• physiology • physiology*},
Abstract = {To address several fundamental questions regarding how
multiwhisker tactile stimuli are integrated and processed by
the trigeminal somatosensory system, a novel behavioral task
was developed that required rats to discriminate the width
of either a wide or narrow aperture using only their large
mystacial vibrissae. Rats quickly acquired this task and
could accurately discriminate between apertures of very
similar width. Accurate discriminations required a large
number of intact facial whiskers. Systematic removal of
individual whiskers caused a decrease in performance that
was directly proportional to the number of whiskers removed,
indicating that tactile information from multiple whiskers
is integrated as rats gauge aperture width. In different
groups of rats, different sets of whiskers were removed in
patterns that preferentially left whisker rows or whisker
arcs intact. These different whisker removals caused similar
decreases in performance, indicating that individual
whiskers within the vibrissal array are functionally
equivalent during performance of this task. Lesions of the
barrel cortex abolished the ability of rats to discriminate,
demonstrating that this region is critically involved in
this tactile behavior. Interestingly, sectioning the facial
nerve, which abolished whisker movements, did not affect the
ability to perform accurate discriminations, indicating that
active whisker movements are not necessary for accurate
performance of the task. Collectively, these results
indicate that the trigeminal somatosensory system forms
internal representations of external stimuli (in this case,
aperture width) by integrating tactile input from many
functionally equivalent facial whiskers and that the
vibrissal array can function as a fine-grained distance
detector without active whisker movements.},
Language = {eng},
Doi = {10.1523/JNEUROSCI.21-15-05752.2001},
Key = {fds275459}
}
@article{fds275427,
Author = {Shuler, MG and Krupa, DJ and Nicolelis, MA},
Title = {Bilateral integration of whisker information in the primary
somatosensory cortex of rats.},
Journal = {Journal of Neuroscience},
Volume = {21},
Number = {14},
Pages = {5251-5261},
Year = {2001},
Month = {July},
ISSN = {1529-2401},
url = {http://www.ncbi.nlm.nih.gov/pubmed/11438600},
Keywords = {Analysis of Variance • Animals • Electrodes,
Implanted • Evoked Potentials • Female •
Functional Laterality • Microinjections • Muscimol
• Neurons • Physical Stimulation • Rats
• Rats, Long-Evans • Reaction Time •
Somatosensory Cortex • Touch • Vibrissae •
administration & dosage • cytology • drug effects
• innervation • physiology •
physiology*},
Abstract = {The isomorphic representation of the contralateral whisker
pad in the rodent cerebral cortex has served as a canonical
example in primary somatosensory areas that the
contralateral body surface is spatially represented as a
topographic map. By characterizing responses evoked by
multiwhisker stimuli, we provide direct evidence that the
whisker region of the rat primary somatosensory cortex (SI)
integrates information from both contralateral and
ipsilateral whisker pads. The proportions of SI neurons
responsive to ipsilateral whisker stimuli, as well as their
response probabilities, increased with the number of
ipsilateral whiskers stimulated. Under bilateral whisker
stimulation, the responses of 95% of neurons recorded were
affected by stimulation of ipsilateral whiskers.
Contralateral tactile responses of SI neurons were
profoundly influenced by preceding ipsilateral stimuli and
vice versa. This effect depended on both the spatial
location and the relative timing of bilateral whisker
stimuli, leading to both spatial and temporal asymmetries of
interaction. Bilateral whisker stimulation resulted in only
modest changes in evoked response latency. Previous
ipsilateral stimulation was also shown to affect tactile
responses evoked by later ipsilateral stimuli. Inactivation
of the opposite SI abolished ipsilaterally evoked responses
as well as their influence on subsequently evoked
contralateral responses in the intact SI. Based on these
results, we conclude that the rat SI integrates information
from both whisker pads and propose that such interactions
may underlie the ability of rats to discriminate bilateral
tactile stimuli.},
Language = {eng},
Doi = {10.1523/JNEUROSCI.21-14-05251.2001},
Key = {fds275427}
}
@article{fds275457,
Author = {Katz, DB and Simon, SA and Nicolelis, MA},
Title = {Dynamic and multimodal responses of gustatory cortical
neurons in awake rats.},
Journal = {Journal of Neuroscience},
Volume = {21},
Number = {12},
Pages = {4478-4489},
Year = {2001},
Month = {June},
ISSN = {1529-2401},
url = {http://www.ncbi.nlm.nih.gov/pubmed/11404435},
Keywords = {Action Potentials • Analysis of Variance • Animals
• Cerebral Cortex • Citric Acid • Electrodes,
Implanted • Female • Male • Microelectrodes
• Neurons • Nicotine • Quinine • Rats
• Rats, Long-Evans • Reaction Time • Signal
Processing, Computer-Assisted • Sodium Chloride •
Somatosensory Cortex • Stimulation, Chemical •
Sucrose • Taste • Wakefulness •
classification • pharmacology • physiology •
physiology*},
Abstract = {To investigate the dynamic aspects of gustatory activity, we
recorded the responses of small ensembles of cortical
neurons to tastants administered to awake rats. Multiple
trials of each tastant were delivered during recordings made
in oral somatosensory (SI) and gustatory cortex (GC). When
integrated tastant responses (firing rates averaged across
2.5 sec) were compared with water responses, 14.4% (13/90)
of the GC neurons responded in a taste-specific manner. When
time was considered as a source of information, however, the
incidence of taste-specific firing increased: as many as 41%
(37/90) of the recorded GC neurons exhibited taste-specific
patterns of response. For 17% of the neurons identified as
responding with taste-specific patterns, the stimulus that
caused the most significant response was a function of the
time since stimulus delivery. That is, a single neuron might
respond most strongly to one tastant in the first 500 msec
of a response and then respond most strongly to another
tastant later in the response. Further analysis of the time
courses of GC and SI cortical neural responses revealed that
modulations of GC firing rate arose from three separable
processes: early somatosensory input (less than
approximately 0.2 sec post-stimulus), later chemosensory
input ( approximately 0.2-1 sec), and delayed somatosensory
input related to orofacial responses (more than
approximately 1.0 sec). These data demonstrate that sensory
information is available in the time course of GC responses
and suggest the viability of views of gustatory processing
that treat the temporal structure of cortical responses as
an integral part of the neural code.},
Language = {eng},
Doi = {10.1523/JNEUROSCI.21-12-04478.2001},
Key = {fds275457}
}
@article{fds275425,
Author = {Ghazanfar, AA and Nicolelis, MA},
Title = {Feature article: the structure and function of dynamic
cortical and thalamic receptive fields.},
Journal = {Cerebral Cortex (New York, N.Y. : 1991)},
Volume = {11},
Number = {3},
Pages = {183-193},
Year = {2001},
Month = {March},
ISSN = {1047-3211},
url = {http://www.ncbi.nlm.nih.gov/pubmed/11230091},
Keywords = {Animals • Auditory Pathways • Geniculate Bodies
• Humans • Somatosensory Cortex • Ventral
Thalamic Nuclei • Visual Cortex • Visual Fields
• Visual Pathways • physiology*},
Abstract = {Under natural conditions, animals must process
spatiotemporally complex signals in order to guide adaptive
behavior. It follows that the response properties of neurons
should reflect the dynamic nature of such signals. Recently,
several studies have demonstrated the existence of
time-varying receptive fields in the auditory, visual and
somatosensory thalamocortical pathways. The characteristics
of these receptive fields suggest that they are constrained
by the need to actively interpret time-varying stimuli.
Here, we review these studies, the possible functions of
these receptive fields, and how they might be generated in
the thalamocortical pathway.},
Language = {eng},
Doi = {10.1093/cercor/11.3.183},
Key = {fds275425}
}
@article{fds275453,
Author = {Nicolelis, MA},
Title = {Actions from thoughts.},
Journal = {Nature},
Volume = {409},
Number = {6818},
Pages = {403-407},
Year = {2001},
Month = {January},
ISSN = {0028-0836},
url = {http://www.ncbi.nlm.nih.gov/pubmed/11201755},
Keywords = {Brain* • Cochlear Implants • Computing
Methodologies* • Epilepsy • Humans • Motor
Activity • Therapy, Computer-Assisted* •
User-Computer Interface • physiology* •
therapy},
Doi = {10.1038/35053191},
Key = {fds275453}
}
@article{fds275455,
Author = {Krupa, DJ and Brisben, AJ and Nicolelis, MA},
Title = {A multi-channel whisker stimulator for producing
spatiotemporally complex tactile stimuli.},
Journal = {Journal of Neuroscience Methods},
Volume = {104},
Number = {2},
Pages = {199-208},
Year = {2001},
Month = {January},
ISSN = {0165-0270},
url = {http://www.ncbi.nlm.nih.gov/pubmed/11164246},
Keywords = {Animals • Female • Neurons • Physical
Stimulation • Rats • Rats, Long-Evans •
Reaction Time • Somatosensory Cortex • Touch
• Ventral Thalamic Nuclei • Vibrissae •
innervation* • instrumentation* • methods* •
physiology • physiology*},
Abstract = {A system is described that delivers complex, biologically
realistic, tactile stimuli to the rat's facial whisker pad
by independently stimulating up to 16 individual facial
whiskers in a flexible yet highly controlled and repeatable
manner. The system is technically simple and inexpensive to
construct. The system consists of an array of 16
miniature-solenoid driven actuators that are attached to 16
individual facial whiskers via very small (130 microm dia.)
Teflon-coated stainless steel wires. When individual
solenoids are energized, the wire is rapidly retracted,
resulting in a deflection of individual whiskers. The rise
time of deflection is approx. 1 mm/ms. Repeatable
stimulation of individual whiskers can be achieved without
touching adjacent whiskers, thereby allowing a very high
density of stimulators to be attached within the spatially
restricted region of the facial whisker pad. Complex
patterns of whisker stimulation (designed to mimic
biologically realistic stimuli) are delivered to the whisker
pad by activating individual solenoid actuators in precisely
controlled temporal patterns. These stimulations can be
combined with multi-electrode single-unit ensemble
recordings at multiple sites within the rat trigeminal
somatosensory system. Analysis of neuronal population
responses to these complex stimuli is intended to examine
how the trigeminal somatosensory system encodes and
processes spatiotemporally complex stimuli.},
Language = {eng},
Doi = {10.1016/s0165-0270(00)00345-9},
Key = {fds275455}
}
@article{fds275277,
Author = {Nicolelis, MAL},
Title = {Advances in neural population coding: Preface},
Journal = {Progress in Brain Research},
Volume = {130},
Pages = {ix-ix},
Publisher = {Elsevier},
Year = {2001},
Month = {January},
ISSN = {0079-6123},
url = {http://dx.doi.org/10.1016/S0079-6123(01)30001-8},
Doi = {10.1016/S0079-6123(01)30001-8},
Key = {fds275277}
}
@article{fds319662,
Author = {Nicolelis, MAL and Shuler, M},
Title = {Thalamocortical and corticocortical interactions in the
somatosensory system},
Journal = {Progress in Brain Research},
Volume = {130},
Pages = {89-110},
Publisher = {Elsevier},
Year = {2001},
Month = {January},
url = {http://dx.doi.org/10.1016/S0079-6123(01)30008-0},
Doi = {10.1016/S0079-6123(01)30008-0},
Key = {fds319662}
}
@article{fds114880,
Title = {Katz DB, Simon SA, Nicolelis MAL (2001) Electrophysiological
studies of gustation in awake rats. In: Methods in
Chemosensory Research (Methods and New Frontiers in
Neuroscience Series, M.A.L. Nicolelis and S.A. Simon, eds.)
CRC Press, pp. 339-357.},
Year = {2001},
Key = {fds114880}
}
@article{fds114934,
Title = {Nicolelis MAL. Actions from thoughts. Nature. 2001 Jan
18;409 Suppl:403-407.},
Year = {2001},
Key = {fds114934}
}
@article{fds275456,
Author = {Nicolelis, MA and Shuler, M},
Title = {Thalamocortical and corticocortical interactions in the
somatosensory system.},
Journal = {Progress in Brain Research},
Volume = {130},
Pages = {90-110},
Year = {2001},
ISSN = {0079-6123},
url = {http://www.ncbi.nlm.nih.gov/pubmed/11480292},
Keywords = {Animals • Cerebral Cortex • Feedback • Humans
• Somatosensory Cortex • Synaptic Transmission
• Thalamus • Touch • Vibrissae •
physiology • physiology*},
Language = {eng},
Doi = {10.1016/S0079-6123(01)30008-0},
Key = {fds275456}
}
@article{fds275410,
Author = {Wessberg, J and Stambaugh, CR and Kralik, JD and Beck, PD and Laubach,
M and Chapin, JK and Kim, J and Biggs, SJ and Srinivasan, MA and Nicolelis,
MA},
Title = {Real-time prediction of hand trajectory by ensembles of
cortical neurons in primates.},
Journal = {Nature},
Volume = {408},
Number = {6810},
Pages = {361-365},
Year = {2000},
Month = {November},
ISSN = {0028-0836},
url = {http://www.ncbi.nlm.nih.gov/pubmed/11099043},
Keywords = {Animals • Aotus trivirgatus • Arm •
Artificial Limbs* • Brain Mapping • Cerebral
Cortex • Frontal Lobe • Motor Activity •
Motor Cortex • Motor Neurons • Neural Conduction
• Parietal Lobe • Robotics* • Signal
Transduction • physiology • physiology*},
Abstract = {Signals derived from the rat motor cortex can be used for
controlling one-dimensional movements of a robot arm. It
remains unknown, however, whether real-time processing of
cortical signals can be employed to reproduce, in a robotic
device, the kind of complex arm movements used by primates
to reach objects in space. Here we recorded the simultaneous
activity of large populations of neurons, distributed in the
premotor, primary motor and posterior parietal cortical
areas, as non-human primates performed two distinct motor
tasks. Accurate real-time predictions of one- and
three-dimensional arm movement trajectories were obtained by
applying both linear and nonlinear algorithms to cortical
neuronal ensemble activity recorded from each animal. In
addition, cortically derived signals were successfully used
for real-time control of robotic devices, both locally and
through the Internet. These results suggest that long-term
control of complex prosthetic robot arm movements can be
achieved by simple real-time transformations of neuronal
population signals derived from multiple cortical areas in
primates.},
Doi = {10.1038/35042582},
Key = {fds275410}
}
@article{fds275393,
Author = {Fanselow, EE and Reid, AP and Nicolelis, MA},
Title = {Reduction of pentylenetetrazole-induced seizure activity in
awake rats by seizure-triggered trigeminal nerve
stimulation.},
Journal = {Journal of Neuroscience},
Volume = {20},
Number = {21},
Pages = {8160-8168},
Year = {2000},
Month = {November},
ISSN = {1529-2401},
url = {http://www.ncbi.nlm.nih.gov/pubmed/11050139},
Keywords = {Animals • Cerebral Cortex • Cortical
Synchronization • Disease Models, Animal •
Electric Stimulation Therapy* • Electrodes, Implanted
• Female • Functional Laterality • Heart Rate
• Membrane Potentials • Pentylenetetrazole •
Rats • Rats, Long-Evans • Reaction Time •
Seizures • Thalamus • Trigeminal Nerve* •
Wakefulness • chemically induced • diagnosis
• physiopathology • therapy*},
Abstract = {Stimulation of the vagus nerve has become an effective
method for desynchronizing the highly coherent neural
activity typically associated with epileptic seizures. This
technique has been used in several animal models of seizures
as well as in humans suffering from epilepsy. However,
application of this technique has been limited to unilateral
stimulation of the vagus nerve, typically delivered
according to a fixed duty cycle, independently of whether
ongoing seizure activity is present. Here, we report that
stimulation of another cranial nerve, the trigeminal nerve,
can also cause cortical and thalamic desynchronization,
resulting in a reduction of seizure activity in awake rats.
Furthermore, we demonstrate that providing this stimulation
only when seizure activity begins results in more effective
and safer seizure reduction per second of stimulation than
with previous methods. Seizure activity induced by
intraperitoneal injection of pentylenetetrazole was recorded
from microwire electrodes in the thalamus and cortex of
awake rats while the infraorbital branch of the trigeminal
nerve was stimulated via a chronically implanted nerve cuff
electrode. Continuous unilateral stimulation of the
trigeminal nerve reduced electrographic seizure activity by
up to 78%, and bilateral trigeminal stimulation was even
more effective. Using a device that automatically detects
seizure activity in real time on the basis of multichannel
field potential signals, we demonstrated that
seizure-triggered stimulation was more effective than the
stimulation protocol involving a fixed duty cycle, in terms
of the percent seizure reduction per second of stimulation.
In contrast to vagus nerve stimulation studies, no
substantial cardiovascular side effects were observed by
unilateral or bilateral stimulation of the trigeminal nerve.
These findings suggest that trigeminal nerve stimulation is
safe in awake rats and should be evaluated as a therapy for
human seizures. Furthermore, the results demonstrate that
seizure-triggered trigeminal nerve stimulation is
technically feasible and could be further developed, in
conjunction with real-time seizure-predicting paradigms, to
prevent seizures and reduce exposure to nerve
stimulation.},
Doi = {10.1523/JNEUROSCI.20-21-08160.2000},
Key = {fds275393}
}
@article{fds275275,
Author = {Ghazanfar, AA and Stambaugh, CR and Nicolelis,
MAL},
Title = {Erratum: Encoding of tactile stimulus location by
somatosensory thalamocortical ensembles (Journal of
Neuroscience (May 15, 2000) (3761- 3775))},
Journal = {The Journal of Neuroscience : the Official Journal of the
Society for Neuroscience},
Volume = {20},
Number = {12},
Pages = {x},
Year = {2000},
Month = {June},
Key = {fds275275}
}
@article{fds364119,
Author = {Ghazanfar, AA and Stambaugh, CR and Nicolelis,
MAL},
Title = {Encoding of tactile stimulus location by somatosensory
thalamocortical ensembles (vol 20, pg 3761,
2000)},
Journal = {The Journal of Neuroscience : the Official Journal of the
Society for Neuroscience},
Volume = {20},
Number = {12},
Pages = {U6-U6},
Publisher = {SOC NEUROSCIENCE},
Year = {2000},
Month = {June},
Key = {fds364119}
}
@article{fds275434,
Author = {Laubach, M and Wessberg, J and Nicolelis, MA},
Title = {Cortical ensemble activity increasingly predicts behaviour
outcomes during learning of a motor task.},
Journal = {Nature},
Volume = {405},
Number = {6786},
Pages = {567-571},
Year = {2000},
Month = {June},
ISSN = {0028-0836},
url = {http://www.ncbi.nlm.nih.gov/pubmed/10850715},
Keywords = {Analysis of Variance • Animals • Electromyography
• Learning • Male • Motor Cortex • Motor
Skills • Neurons • Rats • Reaction Time
• cytology • physiology •
physiology*},
Abstract = {When an animal learns to make movements in response to
different stimuli, changes in activity in the motor cortex
seem to accompany and underlie this learning. The precise
nature of modifications in cortical motor areas during the
initial stages of motor learning, however, is largely
unknown. Here we address this issue by chronically recording
from neuronal ensembles located in the rat motor cortex,
throughout the period required for rats to learn a
reaction-time task. Motor learning was demonstrated by a
decrease in the variance of the rats' reaction times and an
increase in the time the animals were able to wait for a
trigger stimulus. These behavioural changes were correlated
with a significant increase in our ability to predict the
correct or incorrect outcome of single trials based on three
measures of neuronal ensemble activity: average firing rate,
temporal patterns of firing, and correlated firing. This
increase in prediction indicates that an association between
sensory cues and movement emerged in the motor cortex as the
task was learned. Such modifications in cortical ensemble
activity may be critical for the initial learning of motor
tasks.},
Doi = {10.1038/35014604},
Key = {fds275434}
}
@article{fds275419,
Author = {Ghazanfar, AA and Stambaugh, CR and Nicolelis,
MA},
Title = {Encoding of tactile stimulus location by somatosensory
thalamocortical ensembles.},
Journal = {Journal of Neuroscience},
Volume = {20},
Number = {10},
Pages = {3761-3775},
Year = {2000},
Month = {May},
ISSN = {1529-2401},
url = {http://www.ncbi.nlm.nih.gov/pubmed/10804217},
Keywords = {Action Potentials • Anesthesia • Animals •
Behavior, Animal • Discrimination Learning •
Electrophysiology • Female • Models, Neurological*
• Neurons, Afferent • Rats • Rats, Long-Evans
• Reaction Time • Somatosensory Cortex •
Thalamus • Touch • Vibrissae • cytology*
• innervation • physiology •
physiology*},
Abstract = {The exquisite modular anatomy of the rat somatosensory
system makes it an excellent model to test the potential
coding strategies used to discriminate the location of a
tactile stimulus. Here, we investigated how ensembles of
simultaneously recorded single neurons in layer V of primary
somatosensory (SI) cortex and in the ventral posterior
medial (VPM) nucleus of the thalamus of the anesthetized rat
may encode the location of a single whisker stimulus on a
single trial basis. An artificial neural network based on a
learning vector quantization algorithm, was used to identify
putative coding mechanisms. Our data suggest that these
neural ensembles may rely on a distributed coding scheme to
represent the location of single whisker stimuli. Within
this scheme, the temporal modulation of neural ensemble
firing rate, as well as the temporal interactions between
neurons, contributed significantly to the representation of
stimulus location. The relative contribution of these
temporal codes increased with the number of whiskers that
the ensembles must discriminate among. Our results also
indicated that the SI cortex and the VPM nucleus may
function as a single entity to encode stimulus location.
Overall, our data suggest that the representation of
somatosensory features in the rat trigeminal system may
arise from the interactions of neurons within and between
the SI cortex and VPM nucleus. Furthermore, multiple coding
strategies may be used simultaneously to represent the
location of tactile stimuli.},
Doi = {10.1523/JNEUROSCI.20-10-03761.2000},
Key = {fds275419}
}
@article{fds275398,
Author = {Katz, DB and Nicolelis, MA and Simon, SA},
Title = {Nutrient tasting and signaling mechanisms in the gut. IV.
There is more to taste than meets the tongue.},
Journal = {American Journal of Physiology Gastrointestinal and Liver
Physiology},
Volume = {278},
Number = {1},
Pages = {G6-G9},
Year = {2000},
Month = {January},
ISSN = {0193-1857},
url = {http://www.ncbi.nlm.nih.gov/pubmed/10644555},
Keywords = {Animals • Behavior • Central Nervous System •
Epithelium • Humans • Intestines • Nutrition
Physiology* • Signal Transduction* • Taste •
Tongue • physiology • physiology*},
Abstract = {The tongue is the principal organ that provides sensory
information about the quality and quantity of chemicals in
food. Other information about the temperature and texture of
food is also transduced on the tongue, via extragemmal
receptors that form branches of the trigeminal,
glossopharyngeal, and vagal nerves. These systems, together
with information from the gastrointestinal (GI) system,
interact to determine whether or not food is palatable. In
this themes article, emphasis is placed on the integrative
aspects of gustatory processing by showing the convergence
of gustatory information with somatosensory, nociceptive,
and visceral information (from the GI system) on the tongue
and in the brain. Our thesis is that gustation should be
thought of as an integral part of a distributed, interacting
multimodal system in which information from other systems,
including the GI system, can modulate the taste of
food.},
Doi = {10.1152/ajpgi.2000.278.1.G6},
Key = {fds275398}
}
@article{fds114879,
Title = {Ghazanfar AA, Stambaugh CR, Nicolelis MAL (2000) Encoding of
tactile stimulus location by somatosensory thalamocortical
ensembles. J Neurosci 20: 3761-3775.},
Year = {2000},
Key = {fds114879}
}
@article{fds114928,
Title = {Faneslow EE, Reid AP, Nicolelis MAL (2000) Reduction of
pentylenetetrazole-induced seizure activity in awake rats by
seizure-triggered trigeminal nerve stimulation. J Neurosci
20: 8160-8168.},
Year = {2000},
Key = {fds114928}
}
@article{fds114929,
Title = {Ghazanfar AA, Nicolelis MAL (2000) The space-time continuum
in mammalian sensory pathways. In: Time and the Brain (R.
Miller, ed.) Harwood Academic Publishers, Sidney, Australia,
pp. 97-130.},
Year = {2000},
Key = {fds114929}
}
@article{fds114930,
Title = {Katz DB, Nicolelis MAL, Simon SA (2000) There is more to
taste than meets the tongue. Am J Physiol 278:
G6-G9.},
Year = {2000},
Key = {fds114930}
}
@article{fds114931,
Title = {Laubach M, Wessberg J, Nicolelis MAL (2000) Cortical
ensemble activity increasingly predicts behavioral outcomes
during learning of a motor task. Nature 405:
567-571.},
Year = {2000},
Key = {fds114931}
}
@article{fds114932,
Title = {Wessberg J, Stambaugh CR, Kralik JD, Beck PD,
Laubach M, Chapin JK, Kim J, Biggs SJ, Srinivasan MA,
Nicolelis MAL (2000) Real-time prediction of hand trajectory
by ensembles of cortical neurons in primates. Nature 408:
361-365.},
Year = {2000},
Key = {fds114932}
}
@article{fds114943,
Title = {Krupa DJ, Nicolelis MAL (2000) Network level properties of
short-term plasticity in the somatosensory system. Prog
Brain Res 128:161-172.},
Year = {2000},
Key = {fds114943}
}
@article{fds275411,
Author = {Krupa, DJ and Nicolelis, MA},
Title = {Network level properties of short-term plasticity in the
somatosensory system.},
Journal = {Progress in Brain Research},
Volume = {128},
Pages = {161-172},
Year = {2000},
ISSN = {0079-6123},
url = {http://www.ncbi.nlm.nih.gov/pubmed/11105676},
Keywords = {Animals • Denervation • Efferent Pathways •
Feedback • Mechanoreceptors • Nerve Net •
Nerve Regeneration • Neuronal Plasticity •
Neurons, Afferent • Rats • Recovery of Function
• Somatosensory Cortex • Space Perception •
Time Factors • Trigeminal Nuclei • Ventral
Thalamic Nuclei • Vibrissae • adverse effects
• cytology • innervation • physiology •
physiology*},
Doi = {10.1016/S0079-6123(00)28014-X},
Key = {fds275411}
}
@article{fds275397,
Author = {Laubach, M and Shuler, M and Nicolelis, MA},
Title = {Independent component analyses for quantifying neuronal
ensemble interactions.},
Journal = {Journal of Neuroscience Methods},
Volume = {94},
Number = {1},
Pages = {141-154},
Year = {1999},
Month = {December},
ISSN = {0165-0270},
url = {http://www.ncbi.nlm.nih.gov/pubmed/10638821},
Keywords = {Action Potentials • Animals • Behavior, Animal
• Cell Communication • Computer Simulation •
Electrophysiology • Male • Models, Neurological*
• Motor Cortex • Neural Networks (Computer) •
Neurons • Rats • Reaction Time • Statistics
• cytology • physiology •
physiology*},
Abstract = {The goal of this study was to compare how multivariate
statistical methods for dimension reduction account for
correlations between simultaneously recorded neurons. Here,
we describe applications of principal component analysis
(PCA) and independent component analysis (ICA) (Cardoso J-F,
Souloumiac A. IEE-Proc F 1993;140:362-70; Hyvarinen A, Oja
E. Neural Comput 1997;9:1483-92; Lee TW, Girolami M,
Sejnowski TJ. Neural Comp 1999;11:417-41) to neuronal
ensemble data. Simulated ensembles of neurons were used to
compare how well the methods above could account for
correlated neuronal firing. The simulations showed that
'population vectors' defined by PCA were broadly distributed
over the neuronal ensembles; thus, PCA was unable to
identify independent groupings of neurons that shared common
sources of input. By contrast, the ICA methods were all able
to identify groupings of neurons that emerged due to
correlated firing. This result suggests that correlated
neuronal firing is reflected in higher-order correlations
between neurons and not simply in the neurons' covariance.
To assess the significance of these methods for real
neuronal ensembles, we analyzed data from populations of
neurons recorded in the motor cortex of rats trained to
perform a reaction-time task. Scores for PCA and ICA were
reconstructed on a bin-by-bin basis for single trials. These
data were then used to train an artificial neural network to
discriminate between single trials with either short or long
reaction-times. Classifications based on scores from the
ICA-based methods were significantly better than those based
on PCA. For example, scores for components defined with an
ICA-based method, extended ICA (Lee et al., 1999),
classified more trials correctly (80.58+/-1.25%) than PCA
(73.14+/-0.84%) for an ensemble of 26 neurons recorded in
the motor cortex (ANOVA: P < 0.005). This result suggests
that behaviorally relevant information is represented in
correlated neuronal firing and can be best detected when
higher-order correlations between neurons are taken into
account.},
Doi = {10.1016/s0165-0270(99)00131-4},
Key = {fds275397}
}
@article{fds275442,
Author = {Chapin, JK and Nicolelis, MA},
Title = {Principal component analysis of neuronal ensemble activity
reveals multidimensional somatosensory representations.},
Journal = {Journal of Neuroscience Methods},
Volume = {94},
Number = {1},
Pages = {121-140},
Year = {1999},
Month = {December},
ISSN = {0165-0270},
url = {http://www.ncbi.nlm.nih.gov/pubmed/10638820},
Keywords = {Animals • Behavior, Animal • Neurons •
Physical Stimulation • Rats • Rats, Long-Evans
• Sensation • Statistics • Thalamus •
Vibrissae • cytology • physiology •
physiology*},
Abstract = {Principal components analysis (PCA) was used to define the
linearly dependent factors underlying sensory information
processing in the vibrissal sensory area of the ventral
posterior medial (VPM) thalamus in eight awake rats.
Ensembles of up to 23 single neurons were simultaneously
recorded in this area, either during long periods of
spontaneous behavior (including exploratory whisking) or
controlled deflection of single whiskers. PCA rotated the
matrices of correlation between these n neurons into a
series of n uncorrelated principal components (PCs), each
successive PC oriented to explain a maximum of the remaining
variance. The fact that this transformation is
mathematically equivalent to the general Hebb algorithm in
linear neural networks provided a major rationale for
performing it here on data from real neuronal ensembles.
Typically, most information correlated across neurons in the
ensemble was concentrated within the first 3-8 PCs. Each of
these was found to encode distinct, and highly significant
informational factors. These factor encodings were assessed
in two ways, each making use of fact that each PC consisted
of a matrix of weightings, one for each neuron. First, the
neurons were rank ordered according to the locations of the
central whiskers in their receptive fields, allowing their
weightings within different PCs to be viewed as a function
of their position within the whisker representation in the
VPM. Each PC was found to define a distinctly different
topographic mapping of the cutaneous surface. Next, the PCs
were used to weight-sum the neurons' simultaneous activities
to create population vectors (PVs). Each PV consisted of a
single continuous time series which represented the
expression of each PC's 'magnitude' in response to
stimulation of different whiskers, or during behavioral
events such as active tactile whisking. These showed that
each PC functioned as a feature detector capable of
selectively predicting significant sensory or behavioral
events with far greater statistical reliability than could
any single neuron. The encoding characteristics of the first
few PCs were remarkably consistent across all animals and
experimental conditions, including both spontaneous
exploration and direct sensory stimulation: PC1 positively
weighted all neurons, mainly according to their covariance.
Thus it encoded global magnitude of ensemble activity,
caused either by combined sensory inputs or intrinsic
network activity, such as spontaneous oscillations. PC2
encoded spatial position contrast, generally in the
rostrocaudal dimension, across the whole cutaneous surface
represented by the ensemble. PC3 more selectively encoded
contrast in an orthogonal (usually dorsoventral) dimension.
A variable number of higher numbered PCs encoded local
position contrast within one or more smaller regions of the
cutaneous surface. The remaining PCs typically explained
residual 'noise', i.e. the uncorrelated variance that
constituted a major part of each neuron's activity.
Differences in behavioral or sensory experience produced
relatively little in the PC weighting patterns but often
changed the variance they explained (eigenvalues) enough to
alter their ordering. These results argue that PCA provides
a powerful set of tools for selectively measuring neural
ensemble activity within multiple functionally significant
'dimensions' of information processing. As such, it
redefines the 'neuron' as an entity which contributes
portions of its variance to processing not one, but several
tasks.},
Doi = {10.1016/s0165-0270(99)00130-2},
Key = {fds275442}
}
@article{fds275447,
Author = {Fanselow, EE and Nicolelis, MA},
Title = {Behavioral modulation of tactile responses in the rat
somatosensory system.},
Journal = {Journal of Neuroscience},
Volume = {19},
Number = {17},
Pages = {7603-7616},
Year = {1999},
Month = {September},
ISSN = {1529-2401},
url = {http://www.ncbi.nlm.nih.gov/pubmed/10460266},
Keywords = {Animals • Brain Mapping • Electric Stimulation
• Female • Motor Activity • Movement •
Neurons • Ophthalmic Nerve • Physical Stimulation
• Rats • Rats, Long-Evans • Reaction Time
• Somatosensory Cortex • Thalamic Nuclei •
Touch • Vibrissae • innervation • physiology
• physiology*},
Abstract = {We investigated the influence of four different behavioral
states on tactile responses recorded simultaneously via
arrays of microwires chronically implanted in the vibrissal
representations of the rat ventral posterior medial nucleus
(VPM) of the thalamus and the primary somatosensory cortex
(SI). Brief (100 microsecond) electrical stimuli delivered
via a cuff electrode to the infraorbital nerve yielded
robust sensory responses in VPM and SI during states of
quiet immobility. However, significant reductions in tactile
response magnitude and latency were observed in VPM and SI
during large-amplitude, exploratory movements of the
whiskers (at approximately 4-6 Hz). During small-amplitude,
7-12 Hz whisker-twitching movements, a significant reduction
in SI response magnitude and an increase in VPM and SI
response latencies were observed as well. When pairs of
stimuli with interstimulus intervals <100 msec were
delivered during quiet immobility, the response to the
second stimulus in the pair was reduced and occurred at a
longer latency compared with the response to the first
stimulus. In contrast, during large-amplitude whisker
movements and general motor activity, paired stimuli yielded
similar sensory responses at interstimulus intervals >25
msec. These response patterns were correlated with the
amount and duration of postexcitatory firing suppression
observed in VPM and SI during each of these behaviors. On
the basis of these results, we propose that sensory
responses are dynamically modulated during active tactile
exploration to optimize detection of different types of
stimuli. During quiet immobility, the somatosensory system
seems to be optimally tuned to detect the presence of single
stimuli. In contrast, during whisker movements and other
exploratory behaviors, the system is primed to detect the
occurrence of rapid sequences of tactile stimuli, which are
likely to be generated by multiple whisker contacts with
objects during exploratory activity.},
Doi = {10.1523/JNEUROSCI.19-17-07603.1999},
Key = {fds275447}
}
@article{fds275439,
Author = {Katz, DB and Simon, SA and Moody, A and Nicolelis,
MA},
Title = {Simultaneous reorganization in thalamocortical ensembles
evolves over several hours after perioral capsaicin
injections.},
Journal = {Journal of Neurophysiology},
Volume = {82},
Number = {2},
Pages = {963-977},
Year = {1999},
Month = {August},
ISSN = {0022-3077},
url = {http://www.ncbi.nlm.nih.gov/pubmed/10444691},
Keywords = {Analysis of Variance • Animals • Capsaicin •
Female • Injections • Injections, Subcutaneous
• Multivariate Analysis • Neurons • Rats
• Rats, Long-Evans • Somatosensory Cortex •
Thalamus • Vibrissae • drug effects* •
innervation • pharmacology*},
Abstract = {Reorganization of the somatosensory system was quantified by
simultaneously recording from single-unit neural ensembles
in the whisker regions of the ventral posterior medial (VPM)
nucleus of the thalamus and the primary somatosensory (SI)
cortex in anesthetized rats before, during, and after
injecting capsaicin under the skin of the lip. Capsaicin, a
compound that excites and then inactivates a subset of
peripheral C and Adelta fibers, triggered increases in
spontaneous firing of thalamocortical neurons (10-15 min
after injection), as well as rapid reorganization of the
whisker representations in both the VPM and SI. During the
first hour after capsaicin injection, 57% of the 139
recorded neurons either gained or lost at least one whisker
response in their receptive fields (RFs). Capsaicin-related
changes continued to emerge for >/=6 h after the injection:
Fifty percent of the single-neuron RFs changed between 1-2
and 5-6 h after capsaicin injection. Most (79%) of these
late changes represented neural responses that had remained
unchanged in the first postcapsaicin mapping; just under 20%
of these late changes appeared in neurons that had
previously shown no plasticity of response. The majority of
the changes (55% immediately after injection, 66% 6 h later)
involved "unmasking" of new tactile responses. RF change
rates were comparable in SI and VPM (57-49%). Population
analysis indicated that the reorganization was associated
with a lessening of the "spatial coupling" between cortical
neurons-a significant reduction in firing covariance that
could be related to distances between neurons. This general
loss of spatial coupling, in conjunction with increases in
spontaneous firing, may create a situation that is favorable
for the induction of synaptic plasticity. Our results
indicate that the selective inactivation of a peripheral
nociceptor subpopulation can induce rapid and long-evolving
(>/=6 h) shifts in the balance of inhibition and excitation
in the somatosensory system. The time course of these
processes suggest that thalamic and cortical plasticity is
not a linear reflection of spinal and brainstem changes that
occur following the application of capsaicin.},
Doi = {10.1152/jn.1999.82.2.963},
Key = {fds275439}
}
@article{fds275422,
Author = {Krupa, DJ and Ghazanfar, AA and Nicolelis, MA},
Title = {Immediate thalamic sensory plasticity depends on
corticothalamic feedback.},
Journal = {Proceedings of the National Academy of Sciences of the
United States of America},
Volume = {96},
Number = {14},
Pages = {8200-8205},
Year = {1999},
Month = {July},
ISSN = {0027-8424},
url = {http://www.ncbi.nlm.nih.gov/pubmed/10393972},
Keywords = {Animals • Brain Mapping* • Electric Stimulation
• Female • Infusions, Parenteral • Lidocaine
• Muscimol • Nerve Fibers • Neural Pathways
• Neuronal Plasticity* • Neurons • Rats
• Rats, Long-Evans • Somatosensory Cortex •
Thalamus • Time Factors • Trigeminal Nerve •
Vibrissae • administration & dosage • drug effects
• innervation • pharmacology • physiology
• physiology*},
Abstract = {Multiple neuron ensemble recordings were obtained
simultaneously from both the primary somatosensory (SI)
cortex and the ventroposterior medial thalamus (VPM) before
and during the combined administration of reversible
inactivation of the SI cortex and a reversible subcutaneous
block of peripheral trigeminal nerve fibers. This procedure
was performed to quantify the contribution of descending
corticofugal projections on (i) the normal organization of
thalamic somatosensory receptive fields and (ii) the
thalamic somatosensory plastic reorganization that
immediately follows a peripheral deafferentation. Reversible
inactivation of SI cortex resulted in immediate changes in
receptive field properties throughout the VPM. Cortical
inactivation also significantly reduced but did not
completely eliminate the occurrence of VPM receptive field
reorganization resulting from the reversible peripheral
deafferentation. This result suggests that the thalamic
plasticity that is seen immediately after a peripheral
deafferentation is dependent upon both descending
corticofugal projections and ascending trigeminothalamic
projections.},
Doi = {10.1073/pnas.96.14.8200},
Key = {fds275422}
}
@article{fds275392,
Author = {Chapin, JK and Moxon, KA and Markowitz, RS and Nicolelis,
MA},
Title = {Real-time control of a robot arm using simultaneously
recorded neurons in the motor cortex.},
Journal = {Nature Neuroscience},
Volume = {2},
Number = {7},
Pages = {664-670},
Year = {1999},
Month = {July},
ISSN = {1097-6256},
url = {http://www.ncbi.nlm.nih.gov/pubmed/10404201},
Keywords = {Animals • Arm* • Cerebral Cortex • Computer
Systems • Forelimb • Motor Activity* • Motor
Cortex • Movement • Multivariate Analysis •
Nerve Net • Neurons • Rats • Rats, Long-Evans
• Robotics* • Thalamus • innervation •
physiology • physiology*},
Abstract = {To determine whether simultaneously recorded motor cortex
neurons can be used for real-time device control, rats were
trained to position a robot arm to obtain water by pressing
a lever. Mathematical transformations, including neural
networks, converted multineuron signals into 'neuronal
population functions' that accurately predicted lever
trajectory. Next, these functions were electronically
converted into real-time signals for robot arm control.
After switching to this 'neurorobotic' mode, 4 of 6 animals
(those with > 25 task-related neurons) routinely used these
brain-derived signals to position the robot arm and obtain
water. With continued training in neurorobotic mode, the
animals' lever movement diminished or stopped. These results
suggest a possible means for movement restoration in
paralysis patients.},
Doi = {10.1038/10223},
Key = {fds275392}
}
@article{fds275416,
Author = {Ghazanfar, AA and Nicolelis, MA},
Title = {Spatiotemporal properties of layer V neurons of the rat
primary somatosensory cortex.},
Journal = {Cerebral Cortex (New York, N.Y. : 1991)},
Volume = {9},
Number = {4},
Pages = {348-361},
Year = {1999},
Month = {June},
ISSN = {1047-3211},
url = {http://www.ncbi.nlm.nih.gov/pubmed/10426414},
Keywords = {Animals • Electrodes, Implanted • Excitatory
Postsynaptic Potentials • Female • Membrane
Potentials • Microelectrodes • Neurons •
Physical Stimulation • Rats • Rats, Long-Evans
• Somatosensory Cortex • Space Perception •
Time Perception • Vibrissae • anatomy & histology
• cytology • physiology •
physiology*},
Abstract = {Animals in their natural environments actively process
spatiotemporally complex sensory signals in order to guide
adaptive behavior. It therefore seems likely that the
properties of both single neurons and neural ensembles
should reflect the dynamic nature of such interactions.
During exploratory behaviors, rats move their whiskers to
actively discriminate between different tactile features. We
investigated whether this dynamic sensory processing was
reflected in the spatial and temporal properties of neurons
in layer V of the 'whisker area' in the rat primary
somatosensory cortex. We found that the majority of layer V
neurons had large (8.5+/-4.9 whiskers) spatiotemporal
receptive fields (i.e. individual cells responded best to
different whiskers as a function of post-stimulus time), and
that the excitatory responses of surround whiskers formed a
spatial gradient of excitation that seemed to reflect the
greater use of the ventral and caudal whiskers during
natural behaviors. Analyses of ensembles of layer V neurons
revealed that single-whisker stimuli activated a portion of
layer V that extends well beyond a single cortical column
(average of 5.6 barrel cortical columns). Based on these
results, we conclude that the rat primary somatosensory
cortex does not appear to operate as a static decoder of
tactile information. On the contrary, our data suggest that
tactile processing in rats is likely to involve the on-going
interactions between populations of broadly tuned neurons in
the thalamocortical pathway.},
Doi = {10.1093/cercor/9.4.348},
Key = {fds275416}
}
@article{fds275273,
Author = {Nicolelis, MAL and De Schutter and E},
Title = {Editorial},
Journal = {Journal of Neuroscience Methods},
Volume = {94},
Number = {1},
Pages = {3-4},
Publisher = {ELSEVIER SCIENCE BV},
Year = {1999},
Month = {January},
url = {http://dx.doi.org/10.1016/S0165-0270(99)00170-3},
Doi = {10.1016/S0165-0270(99)00170-3},
Key = {fds275273}
}
@article{fds114877,
Title = {Fanselow E, Nicolelis MAL (1999) Behavioral modulation of
tactile responses in the rat somatosensory system. J
Neurosci 19: 7603-7616.},
Year = {1999},
Key = {fds114877}
}
@article{fds114878,
Title = {Laubach M, Shuler M, Nicolelis MAL (1999) Independent
component analyses for quantifying neuronal ensemble
interactions. J Neurosci Meth 94: 141-154.},
Year = {1999},
Key = {fds114878}
}
@article{fds114915,
Title = {Krupa DJ, Ghazanfar AA, Nicolelis MAL (1999) Immediate
thalamic sensory plasticity depends on corticothalamic
feedback. Proc Natl Acad Sci USA 96: 8200-8205.},
Year = {1999},
Key = {fds114915}
}
@article{fds114924,
Title = {Chapin JK, Nicolelis MAL (1999) Principal component analysis
of neuronal ensemble activity reveals multidimensional
sensory representations. J Neurosci Meth 94:
121-140.},
Year = {1999},
Key = {fds114924}
}
@article{fds114925,
Title = {Chapin JK, Markowitz RS, Moxon KA, Nicolelis MAL (1999)
Real-time control of a robot arm using simultaneously
recorded neurons in the motor cortex. Nature Neurosci 2:
664-670.},
Year = {1999},
Key = {fds114925}
}
@article{fds114926,
Title = {Ghazanfar AA, Nicolelis MAL (1999) Spatiotemporal properties
of layer V neurons in the rat primary somatosensory cortex.
Cerebral Cortex 9: 348-361.},
Year = {1999},
Key = {fds114926}
}
@article{fds114927,
Title = {Katz DB, Simon SA, Nicolelis MAL (1999) Simultaneous
reorganization in thalamcortical ensembles evolves over
several hours after perioral capsaicin injections. J
Neurophysiol 82: 963-977.},
Year = {1999},
Key = {fds114927}
}
@article{fds275391,
Author = {Nicolelis, MA and Ghazanfar, AA and Stambaugh, CR and Oliveira, LM and Laubach, M and Chapin, JK and Nelson, RJ and Kaas,
JH},
Title = {Simultaneous encoding of tactile information by three
primate cortical areas.},
Journal = {Nature Neuroscience},
Volume = {1},
Number = {7},
Pages = {621-630},
Year = {1998},
Month = {November},
ISSN = {1097-6256},
url = {http://www.ncbi.nlm.nih.gov/pubmed/10196571},
Keywords = {Action Potentials • Animals • Aotidae •
Electrophysiology • Hand • Neurons • Physical
Stimulation • Reaction Time • Somatosensory Cortex
• Touch • cytology • physiology •
physiology*},
Abstract = {We used simultaneous multi-site neural ensemble recordings
to investigate the representation of tactile information in
three areas of the primate somatosensory cortex (areas 3b,
SII and 2). Small neural ensembles (30-40 neurons) of
broadly tuned somatosensory neurons were able to identify
correctly the location of a single tactile stimulus on a
single trial, almost simultaneously. Furthermore, each of
these cortical areas could use different combinations of
encoding strategies, such as mean firing rate (areas 3b and
2) or temporal patterns of ensemble firing (area SII), to
represent the location of a tactile stimulus. Based on these
results, we propose that ensembles of broadly tuned neurons,
located in three distinct areas of the primate somatosensory
cortex, obtain information about the location of a tactile
stimulus almost concurrently.},
Doi = {10.1038/2855},
Key = {fds275391}
}
@article{fds114870,
Title = {Nicolelis MAL, Ghazanfar AA, Oliveira LMO, Chapin JK, Nelson
R, Kaas JH (1998) Simultaneous encoding of tactile
information by three primate cortical areas. Nature Neurosci
1: 621-630.},
Year = {1998},
Key = {fds114870}
}
@article{fds275444,
Author = {Nicolelis, MA and Katz, D and Krupa, DJ},
Title = {Potential circuit mechanisms underlying concurrent thalamic
and cortical plasticity.},
Journal = {Reviews in the Neurosciences},
Volume = {9},
Number = {3},
Pages = {213-224},
Year = {1998},
ISSN = {0334-1763},
url = {http://www.ncbi.nlm.nih.gov/pubmed/9833652},
Keywords = {Animals • Cerebral Cortex • Humans • Neural
Pathways • Neuronal Plasticity • Sensation •
Thalamus • physiology • physiology*},
Abstract = {During the last two decades, plastic reorganization of both
sensory and motor representations in the adult central
nervous system has been demonstrated following a large
variety of manipulations, ranging from partial lesions of
the sensory receptor surface to modifications in sensory
experience (see /14/ for review). Yet, little is known about
the neural circuit mechanisms underlying such reorganization
process. Despite the difficulty in addressing this issue,
recent studies have provided some insights into this
fundamental question. Altogether, these studies suggest that
the process of plastic reorganization is a system-wide
phenomenon, involving both cortical and subcortical
representations. Contrary to classical beliefs, recent work
also suggests that the final outcome of the reorganization
process is not necessarily beneficial, since it can lead to
abnormal perceptual experiences /31/, such as the phantom
limb sensation, and even pain /31,32/. In this review, we
focus on recent insights into the possible circuit
mechanisms underlying sensory plasticity and discuss the
potential implications of these findings. We then present
physiological evidence supporting the view that the process
of plasticity observed at the cortical level may reflect
simultaneous changes in many subcortical
structures.},
Doi = {10.1515/revneuro.1998.9.3.213},
Key = {fds275444}
}
@article{fds275424,
Author = {Lin, RC and Nicolelis, MA and Chapin, JK},
Title = {Topographic and laminar organizations of the incertocortical
pathway in rats.},
Journal = {Neuroscience},
Volume = {81},
Number = {3},
Pages = {641-651},
Year = {1997},
Month = {December},
ISSN = {0306-4522},
url = {http://www.ncbi.nlm.nih.gov/pubmed/9316017},
Keywords = {Anatomy, Artistic • Animals • Brain Mapping •
Cerebral Cortex • Fluorescent Dyes • Medical
Illustration • Neural Pathways • Rats • Rats,
Inbred Strains • Thalamic Nuclei • anatomy &
histology • physiology • physiology*},
Abstract = {The topographic and laminar organizations of the projection
system from the zona incerta to the neocortex were studied
by using both retrograde and anterograde methods in the rat.
Injections of retrograde fluorescent tracers into different
cortical areas revealed that the incertocortical projection
neurons have a rough topographic organization with respect
to their cortical targets. Furthermore, the incertocortical
projecting neurons were found mainly in the dorsal and
rostral subdivisions of the zona incerta, and none were
found in the ventral subdivision. In cases which included
three different fluorescent tracers injected into the
frontal, the parietal and the occipital cortices,
retrogradely single-labelled cells were found intermingled
within the dorsal zona incerta. Very few double-labelled
cells were noted, and triple-labelled cells were absent.
Injections of anterograde tracers into the dorsal zona
incerta demonstrate that labelled fibres traverse the
striatum and terminate most densely in the outer half of
layer I of the neocortex. The density of incertocortical
terminals was greatest in the somatosensory cortex, while
the innervation of visual cortical areas was sparse. Very
fine and sparse bouton-like swellings of labelled
incertocortical fibres were found running parallel along the
pial surface. Since it has recently been shown that the
incertocortical projections derive from GABAergic neurons,
the present results suggest that the diffuse and roughly
topographic projection from the zona incerta to the cerebral
cortex may play an inhibitory role in widespread areas of
cerebral cortex. This inhibitory action may preferentially
target the distal dendrites of cortical neurons, since the
majority of incertocortical terminals were found in the
outer part of layer I of the neocortex.},
Doi = {10.1016/s0306-4522(97)00094-8},
Key = {fds275424}
}
@article{fds275437,
Author = {Nicolelis, MA and Lin, RC and Chapin, JK},
Title = {Neonatal whisker removal reduces the discrimination of
tactile stimuli by thalamic ensembles in adult
rats.},
Journal = {Journal of Neurophysiology},
Volume = {78},
Number = {3},
Pages = {1691-1706},
Year = {1997},
Month = {September},
ISSN = {0022-3077},
url = {http://www.ncbi.nlm.nih.gov/pubmed/9310453},
Keywords = {Animals • Animals, Newborn • Discrimination
(Psychology) • Neuronal Plasticity • Neurons,
Afferent • Rats • Thalamus • Touch •
Vibrissae • growth & development* • physiology
• physiology*},
Abstract = {Simultaneous recordings of up to 48 single neurons per
animal were used to characterize the long-term functional
effects of sensory plastic modifications in the ventral
posterior medial nucleus (VPM) of the thalamus following
unilateral removal of facial whiskers in newborn rats. One
year after this neonatal whisker deprivation, neurons in the
contralateral VPM responded to cutaneous stimulation of the
face at much longer minimal latencies (15.2 +/- 8.2 ms, mean
+/- SD) than did normal cells (8.8 +/- 5.3 ms) in the same
subregion of the VPM. In 69% of these neurons, the initial
sensory responses to stimulus offset were followed for up to
700 ms by reverberant trains of bursting discharge,
alternating in 100-ms cycles with inhibition. Receptive
fields in the deafferented VPM were also atypical in that
they extended over the entire face, shoulder, forepaw,
hindpaw, and even ipsilateral whiskers. Discriminant
analysis (DA) was then used to statistically evaluate how
this abnormal receptive field organization might affect the
ability of thalamocortical neuronal populations to
"discriminate" somatosensory stimulus location. To
standardize this analysis, three stimulus targets ("groups")
were chosen in all animals such that they triangulated the
central region of the "receptive field" of the recorded
multineuronal ensemble. In the normal animals these stimulus
targets were whiskers or perioral hairs; in the deprived
animals the targets typically included hairy skin of the
body as well as face. The measured variables consisted of
each neuron's spiking response to each stimulus
differentiated into three poststimulus response epochs
(0-15, 15-30, and 30-45 ms). DA quantified the statistical
contribution of each of these variables to its overall
discrimination between the three stimulus sites. In the
normal animals, the stimulus locations were correctly
classified in 88.2 +/- 3.7% of trials on the basis of the
spatiotemporal patterns of ensemble activity derived from up
to 18 single neurons. In the deprived animals, the stimulus
locations were much less consistently discriminated (reduced
to 73.5 +/- 12.6%; difference from controls significant at P
< 0.01) despite the fact that much more widely spaced
stimulus targets were used and even when up to 20 neurons
were included in the ensemble. Overall, these results
suggest that neonatal damage to peripheral sense organs may
produce marked changes in the physiology of individual
neurons in the somatosensory thalamus. Moreover, the present
demonstration that these changes can profoundly alter
sensory discrimination at the level of neural populations in
the thalamus provides important evidence that the well-known
perceptual effects of chronic peripheral deprivation may be
partially attributable to plastic reorganization at
subcortical levels.},
Doi = {10.1152/jn.1997.78.3.1691},
Key = {fds275437}
}
@article{fds275451,
Author = {Faggin, BM and Nguyen, KT and Nicolelis, MA},
Title = {Immediate and simultaneous sensory reorganization at
cortical and subcortical levels of the somatosensory
system.},
Journal = {Proceedings of the National Academy of Sciences of the
United States of America},
Volume = {94},
Number = {17},
Pages = {9428-9433},
Year = {1997},
Month = {August},
ISSN = {0027-8424},
url = {http://www.ncbi.nlm.nih.gov/pubmed/9256499},
Keywords = {Animals • Neuronal Plasticity* • Psychomotor
Performance • Rats • Somatosensory Cortex •
physiology*},
Abstract = {The occurrence of cortical plasticity during adulthood has
been demonstrated using many experimental paradigms. Whether
this phenomenon is generated exclusively by changes in
intrinsic cortical circuitry, or whether it involves
concomitant cortical and subcortical reorganization, remains
controversial. Here, we addressed this issue by
simultaneously recording the extracellular activity of up to
135 neurons in the primary somatosensory cortex, ventral
posterior medial nucleus of the thalamus, and trigeminal
brainstem complex of adult rats, before and after a
reversible sensory deactivation was produced by subcutaneous
injections of lidocaine. Following the onset of the
deactivation, immediate and simultaneous sensory
reorganization was observed at all levels of the
somatosensory system. No statistical difference was observed
when the overall spatial extent of the cortical (9.1 +/- 1.2
whiskers, mean +/- SE) and the thalamic (6.1 +/- 1.6
whiskers) reorganization was compared. Likewise, no
significant difference was found in the percentage of
cortical (71.1 +/- 5.2%) and thalamic (66. 4 +/- 10.7%)
neurons exhibiting unmasked sensory responses. Although
unmasked cortical responses occurred at significantly higher
latencies (19.6 +/- 0.3 ms, mean +/- SE) than thalamic
responses (13. 1 +/- 0.6 ms), variations in neuronal latency
induced by the sensory deafferentation occurred as often in
the thalamus as in the cortex. These data clearly
demonstrate that peripheral sensory deafferentation triggers
a system-wide reorganization, and strongly suggest that the
spatiotemporal attributes of cortical plasticity are
paralleled by subcortical reorganization.},
Doi = {10.1073/pnas.94.17.9428},
Key = {fds275451}
}
@article{fds275435,
Author = {Nicolelis, MA and Fanselow, EE and Ghazanfar, AA},
Title = {Hebb's dream: the resurgence of cell assemblies.},
Journal = {Neuron},
Volume = {19},
Number = {2},
Pages = {219-221},
Year = {1997},
Month = {August},
ISSN = {0896-6273},
url = {http://www.ncbi.nlm.nih.gov/pubmed/9292712},
Keywords = {Animals • Hippocampus • Neuronal Plasticity •
Neurons, Afferent • Presynaptic Terminals •
physiology*},
Doi = {10.1016/s0896-6273(00)80932-0},
Key = {fds275435}
}
@article{fds275395,
Author = {Ghazanfar, AA and Nicolelis, MA},
Title = {Nonlinear processing of tactile information in the
thalamocortical loop.},
Journal = {Journal of Neurophysiology},
Volume = {78},
Number = {1},
Pages = {506-510},
Year = {1997},
Month = {July},
ISSN = {0022-3077},
url = {http://www.ncbi.nlm.nih.gov/pubmed/9242297},
Keywords = {Animals • Cerebral Cortex • Mental Processes
• Neurons • Nonlinear Dynamics • Rats •
Thalamus • Touch • Vibrissae • cytology
• physiology*},
Abstract = {Rats explore tangible objects in a manner such that, at any
given moment in time, multiple facial whiskers
simultaneously contact the surface of the object. Although
both thalamic and cortical neurons responsible for
processing such tactile information have large, multiwhisker
receptive fields, it remains unclear what kinds of
computations can be carried out by these neuronal
populations when behaviorally relevant multiwhisker stimuli
are used. By simultaneously recording the activity of up to
78 cortical and thalamic neurons per animal, we observed
that the magnitude of sensory responses and the spatial
spread of ensemble activity increased in a nonlinear fashion
according to the extent and spatial orientation of the
multiwhisker stimuli. Supralinear responses were seen more
frequently with vertically than with horizontally oriented
stimuli. These data suggest that thalamocortical
interactions in the rat somatosensory system can generate
complex spatial transformations of multiwhisker stimuli that
go beyond the classic inhibitory interactions previously
observed.},
Doi = {10.1152/jn.1997.78.1.506},
Key = {fds275395}
}
@article{fds275394,
Author = {Nicolelis, MA and Ghazanfar, AA and Faggin, BM and Votaw, S and Oliveira, LM},
Title = {Reconstructing the engram: simultaneous, multisite, many
single neuron recordings.},
Journal = {Neuron},
Volume = {18},
Number = {4},
Pages = {529-537},
Year = {1997},
Month = {April},
ISSN = {0896-6273},
url = {http://www.ncbi.nlm.nih.gov/pubmed/9136763},
Keywords = {Animals • Brain • Cell Communication •
Electrophysiology • Equipment Design •
Extracellular Space • Neurons • Rats •
cytology • instrumentation • methods* •
physiology • physiology*},
Abstract = {Little is known about the physiological principles that
govern large-scale neuronal interactions in the mammalian
brain. Here, we describe an electrophysiological paradigm
capable of simultaneously recording the extracellular
activity of large populations of single neurons, distributed
across multiple cortical and subcortical structures in
behaving and anesthetized animals. Up to 100 neurons were
simultaneously recorded after 48 microwires were implanted
in the brain stem, thalamus, and somatosensory cortex of
rats. Overall, 86% of the implanted microwires yielded
single neurons, and an average of 2.3 neurons were
discriminated per microwire. Our population recordings
remained stable for weeks, demonstrating that this method
can be employed to investigate the dynamic and distributed
neuronal ensemble interactions that underlie processes such
as sensory perception, motor control, and sensorimotor
learning in freely behaving animals.},
Doi = {10.1016/s0896-6273(00)80295-0},
Key = {fds275394}
}
@article{fds275367,
Author = {Nicolelis, MAL},
Title = {Dynamic and distributed somatosensory representations as the
substrate for cortical and subcortical plasticity},
Journal = {Seminars in Neuroscience},
Volume = {9},
Number = {1-2},
Pages = {24-33},
Publisher = {Elsevier BV},
Year = {1997},
Month = {January},
url = {http://dx.doi.org/10.1006/smns.1997.0103},
Abstract = {Seconds after a cutaneous deafferentation is induced in
adult animals, a complex process of plastic reorganization
is triggered in the subcortical and cortical structures that
form the somatosensory system. This process, which leads to
the immediate unmasking of novel neuronal sensory responses,
continues to evolve for many weeks and months until most of
the neuronal tissue deprived of its original afferent input
gains responsiveness to surrounding skin territories. Here,
I propose that the existence of dynamic and distributed
sensory representations throughout the somatosensory system
offers the substrate for the occurrence of immediate plastic
remapping of the body surface following either a peripheral
injury or a change in sensory experience.},
Doi = {10.1006/smns.1997.0103},
Key = {fds275367}
}
@article{fds114874,
Title = {Ghazanfar AA, Nicolelis MAL (1997) Non-linear processing
of tactile information in the thalamocortical loop. J
Neurophysiol 78:506-510.},
Year = {1997},
Key = {fds114874}
}
@article{fds114875,
Title = {Nicolelis MAL, Fanselow E, Ghazanfar AA (1997) Hebb's dream:
The resurgence of cell assemblies. Neuron
19(2):219-221.},
Year = {1997},
Key = {fds114875}
}
@article{fds114876,
Title = {Nicolelis MAL, Lin RCS, Chapin JK (1997) Neonatal whisker
removal reduces the discrimination of tactile stimuli by
thalamic ensembles in adult rats. J Neurophysiol 78:
1691-1706.},
Year = {1997},
Key = {fds114876}
}
@article{fds114920,
Title = {Faggin B, Ngyuen KT, Nicolelis MAL (1997) Immediate and
simultaneous plastic reorganization at multiple levels of
the somatosensory system. Proc Natl Acad Soc USA
94:9428-9433.},
Year = {1997},
Key = {fds114920}
}
@article{fds114921,
Title = {Nicolelis MAL (1997) Dynamic and distributed somatosensory
organization as the substrate for cortical and subcortical
plasticity. Seminars in Neurosciences 9:24-33.},
Year = {1997},
Key = {fds114921}
}
@article{fds114922,
Title = {Nicolelis MAL, Ghazanfar AA, Faggin B, Votaw S, Oliveira LMO
(1997) Reconstructing the engram: simultaneous, multiple
site, many single neuron recordings. Neuron
18:529-537},
Year = {1997},
Key = {fds114922}
}
@article{fds114923,
Title = {Lin CS, Nicolelis MAL, Chapin JK (1997) Topography and
laminar organization of the incertocortical pathway in rats.
Neuroscience 81: 641-651.},
Year = {1997},
Key = {fds114923}
}
@article{fds275414,
Author = {Nicolelis, MA and De Oliveira and LM and Lin, RC and Chapin,
JK},
Title = {Active tactile exploration influences the functional
maturation of the somatosensory system.},
Journal = {Journal of Neurophysiology},
Volume = {75},
Number = {5},
Pages = {2192-2196},
Year = {1996},
Month = {May},
ISSN = {0022-3077},
url = {http://www.ncbi.nlm.nih.gov/pubmed/8734618},
Keywords = {Animals • Animals, Newborn • Denervation •
Exploratory Behavior • Facial Nerve • Neurons,
Afferent • Rats • Somatosensory Cortex •
Thalamus • Touch • Vibrissae • growth &
development • growth & development* • physiology
• physiology*},
Abstract = {1. The hypothesis that active exploration of objects is
required for the functional maturation of neuronal circuits
subserving tactile perception was tested by subjecting 8- to
11-day old rats to a complete unilateral section of the
facial nerve. This procedure selectively abolished whisker
protraction movements without affecting the sensory
innervation of the facial vibrissae, the tactile organs used
by rats to discriminate object texture and shape. 2. Six to
14 mo after the facial nerve section, simultaneous
recordings of neuronal ensembles located in the ventral
posterior medial nucleus (VPM) of the thalamus revealed a
marked reduction in receptive field (RF) size (in terms of
number of whiskers), and the formation of abnormal RF
surrounds, spanning the face and contiguous body regions. In
addition, the directional organization of VPM RFs,
represented by caudal to rostral shifts in RF centers over
30 ms following whisker stimulation, was greatly reduced in
these animals. 3. These results suggest that neonatal active
tactile exploration is required to establish normal
spatiotemporal patterning of neuronal RFs within the
somatosensory system, and consequently, to develop normal
tactile perception.},
Doi = {10.1152/jn.1996.75.5.2192},
Key = {fds275414}
}
@article{fds275441,
Author = {Nicolelis, MA},
Title = {Beyond maps: a dynamic view of the somatosensory
system.},
Journal = {Brazilian Journal of Medical and Biological Research =
Revista Brasileira De Pesquisas Medicas E
Biologicas},
Volume = {29},
Number = {4},
Pages = {401-412},
Year = {1996},
Month = {April},
ISSN = {0100-879X},
url = {http://www.ncbi.nlm.nih.gov/pubmed/8736103},
Keywords = {Animals • Nerve Net • Rats • Somatosensory
Cortex • physiology*},
Abstract = {Current theories on how tactile information is processed by
the mammalian somatosensory system are based primarily on
data obtained in studies in which the physiological
properties of single neurons were characterized, one at a
time, in behaving or anesthetized animals. Yet, the central
nervous system relies on the concurrent activation of large
populations of neurons to process the variety of sensory
stimuli that contribute to normal tactile perception. The
recent introduction of electrophysiological methods for
chronic and simultaneous recordings of the extracellular
activity of large numbers of single neurons per animal has
allowed us to investigate, for the first time, how
populations of neurons, located at multiple processing
stages of the somatosensory system, interact following
passive and active tactile stimulation. The rat trigeminal
somatosensory system was used as a model for this
investigation. Our results revealed the existence of highly
dynamic and distributed representations of tactile
information, not only in the somatosensory cortex, but also
in the thalamus and even in the brainstem. In these
structures, we identified broadly tuned neurons with
multiwhisker receptive fields (RFs). In the thalamus, a
large percentage of neurons exhibited shifts in the spatial
domain of their RFs as a function of post-stimulus time.
During these shifts, the center of the neuron's RF moved
across the whisker pad from caudal to rostral whiskers, but
not in the opposite direction, suggesting that these
spatiotemporal RFs may encode directional information.
Further studies revealed that somatosensory representations
were maintained by dynamic interactions between multiple
convergent afferents, since they could be altered in a
matter of seconds by reversible sensory deprivations.
Overall, these results suggest that the rat somatosensory
system relies on both spatial and temporal interactions
between populations of cortical and subcortical neurons to
process multiple attributes of tactile stimuli.},
Key = {fds275441}
}
@article{fds275415,
Author = {Lin, RC and Nicolelis, MA and Zhou, HL and Chapin,
JK},
Title = {Calbindin-containing non-specific thalamocortical projecting
neurons in the rat.},
Journal = {Brain Research},
Volume = {711},
Number = {1-2},
Pages = {50-55},
Year = {1996},
Month = {March},
ISSN = {0006-8993},
url = {http://www.ncbi.nlm.nih.gov/pubmed/8680874},
Keywords = {Animals • Calcium-Binding Protein, Vitamin D-Dependent
• Cerebral Cortex • Female •
Immunohistochemistry • Male • Neural Pathways
• Rats • Thalamus • anatomy & histology*
• chemistry*},
Abstract = {Immunoreactivity for calcium binding proteins was used to
demonstrate the neurochemical profiles of non-specific
thalamocortical neurons located in the ventromedial nucleus,
the centrolateral nucleus, and the nucleus reuniens that
project to the somatosensory cortex in the adult rat.
Cortical injections of fluorescent tracers combined with
immunohistochemistry for calcium binding proteins revealed
that retrogradely labeled neurons in these three thalamic
nuclei are immunoreactive for calbindin. The present results
suggest the presence of a chemically distinct non-specific
thalamocortical system which terminates in the
neocortex.},
Doi = {10.1016/0006-8993(95)01381-4},
Key = {fds275415}
}
@article{fds114872,
Title = {Chapin JK, Nicolelis MAL (1996) Neural network mechanisms of
oscillatory brain states: characterization using
simultaneous multi-single neuron recordings., In: Continuous
waveform analysis, R.M. Basheiss and D.J. Vicent (eds).
Electroenceph Clin Neurophysiol, suppl 45, pp
113-122.},
Year = {1996},
Key = {fds114872}
}
@article{fds114873,
Title = {Lin RCS, Nicolelis MAL, Zhou HL, Chapin JK (1996)
Calbindin-containing, non-specific thalamocortical
projecting neurons in the rat. Brain Research 711:
50-55.},
Year = {1996},
Key = {fds114873}
}
@article{fds114918,
Title = {Nicolelis MAL, Oliveira LMO, Lin RCS, Chapin JK (1996)
Active tactile exploration influences the functional
maturation of the somatosensory system. J Neurophysiol 17:
2192-2196.},
Year = {1996},
Key = {fds114918}
}
@article{fds114919,
Title = {Nicolelis MAL (1996) Beyond maps: A dynamic view of the
somatosensory system. Braz J Med Biol Res 29:
401-412.},
Year = {1996},
Key = {fds114919}
}
@article{fds275408,
Author = {Chapin, JK and Nicolelis, MA},
Title = {Neural network mechanisms of oscillatory brain states:
characterization using simultaneous multi-single neuron
recordings.},
Journal = {Electroencephalography and Clinical Neurophysiology.
Supplement},
Volume = {45},
Pages = {113-122},
Year = {1996},
ISSN = {0424-8155},
url = {http://www.ncbi.nlm.nih.gov/pubmed/8930518},
Keywords = {Animals • Brain • Electroencephalography •
Face • Nerve Net • Neurons • Oscillometry
• Periodicity • Rats • Somatosensory Cortex
• Thalamus • Vibrissae • cytology •
physiology • physiology*},
Key = {fds275408}
}
@article{fds275404,
Author = {Nicolelis, MA and Baccala, LA and Lin, RC and Chapin,
JK},
Title = {Sensorimotor encoding by synchronous neural ensemble
activity at multiple levels of the somatosensory
system.},
Journal = {Science (New York, N.Y.)},
Volume = {268},
Number = {5215},
Pages = {1353-1358},
Year = {1995},
Month = {June},
ISSN = {0036-8075},
url = {http://www.ncbi.nlm.nih.gov/pubmed/7761855},
Keywords = {Animals • Brain • Electromyography •
Electrophysiology • Motor Cortex • Nerve Net
• Neural Pathways • Neurons, Afferent • Rats
• Somatosensory Cortex • Thalamic Nuclei •
Touch • Trigeminal Ganglion • Trigeminal Nuclei
• Vibrissae • innervation* • physiology
• physiology*},
Abstract = {Neural ensemble processing of sensorimotor information
during behavior was investigated by simultaneously recording
up to 48 single neurons at multiple relays of the rat
trigeminal somatosensory system. Cortical, thalamic, and
brainstem neurons exhibited widespread 7- to 12-hertz
synchronous oscillations, which began during attentive
immobility and reliably predicted the imminent onset of
rhythmic whisker twitching. Each oscillatory cycle began as
a traveling wave of neural activity in the cortex that then
spread to the thalamus. Just before the onset of rhythmic
whisker twitching, the oscillations spread to the spinal
trigeminal brainstem complex. Thereafter, the oscillations
at all levels were synchronous with whisker protraction.
Neural structures manifesting these rhythms also exhibited
distributed spatiotemporal patterns of neuronal ensemble
activity in response to tactile stimulation. Thus,
multilevel synchronous activity in this system may encode
not only sensory information but also the onset and temporal
domain of tactile exploratory movements.},
Doi = {10.1126/science.7761855},
Key = {fds275404}
}
@article{fds275450,
Author = {Nicolelis, MA and Chapin, JK and Lin, RC},
Title = {Development of direct GABAergic projections from the zona
incerta to the somatosensory cortex of the
rat.},
Journal = {Neuroscience},
Volume = {65},
Number = {2},
Pages = {609-631},
Year = {1995},
Month = {March},
ISSN = {0306-4522},
url = {http://www.ncbi.nlm.nih.gov/pubmed/7777173},
Keywords = {Animals • Calcium-Binding Protein, Vitamin D-Dependent
• Electron Transport Complex IV • Fluorescent Dyes
• Glutamate Decarboxylase • Immunohistochemistry
• Neural Pathways • Parvalbumins • Rats
• Somatosensory Cortex • Stilbamidines* •
Thalamic Nuclei • Thalamus • anatomy & histology
• cytology • gamma-Aminobutyric Acid • growth
& development • growth & development* • metabolism
• physiology*},
Abstract = {The postnatal development of direct thalamocortical
projections from the zona incerta of the ventral thalamus to
the whisker representation area of the rat primary
somatosensory cortex was investigated. Cytoarchitectonic
analysis based on Nissl staining, cytochrome oxidase
histochemistry and immunohistochemistry for glutamic acid
decarboxylase, GABA, parvalbumin and calbindin D28K revealed
that the zona incerta can be clearly distinguished from
surrounding diencephalic structures from the day of birth.
Moreover, four distinct anatomical subdivisions of this
nucleus were identified: the rostral, dorsal, ventral and
caudal. Of these, the ventral subdivision is by far the most
conspicuous, containing the highest density of neurons, and
the highest levels of cytochrome oxidase, glutamate
decarboxylase, GABA, parvalbumin and calbindin D28K. In
contrast, the dorsal, rostral and caudal subdivisions
contain fewer cells, lower levels of glutamic acid
decarboxylase and GABA and very few parvalbumin-positive and
calbindin-positive neurons. Small injections of rhodamine
coated microspheres or Fluoro-gold in the primary
somatosensory cortex of animals at different stages of
development revealed the existence of retrogradely labeled
neurons in the rostral and dorsal subdivisions of the zona
incerta from postnatal day 1. At this age, retrogradely
labeled cells were also found in the ventral lateral,
ventral posterior medial, posterior medial, centrolateral,
ventral medial and magnocellular subdivision of the medial
geniculate nuclei of the dorsal thalamus. The density of the
incertocortical projection reaches its maximum between the
first and second postnatal weeks, decreasing subsequently,
until an adult pattern of labeling is achieved. Tracer
injections combined with immunohistochemistry revealed that
the majority of the incertocortical projection derives from
GABAergic neurons, implying a potentially inhibitory role
for the incertocortical projection. These results
demonstrate that the rat trigeminal system contains parallel
thalamocortical pathways of opposite polarity, emerging from
both the dorsal (glutamatergic, excitatory) and ventral
(GABAergic, inhibitory) thalamus since the day of birth. As
such, these findings suggest that, contrary to the classical
notion, not only the dorsal but also the ventral thalamus
may play a special role in both cortical maturation and
function.},
Doi = {10.1016/0306-4522(94)00493-o},
Key = {fds275450}
}
@article{fds114914,
Title = {Nicolelis MAL, Baccala LA, Lin RCS, Chapin JK (1995)
Sensorimotor encoding by synchronous neural ensemble
activity at multiple levels of the somatosensory system.
Science 268: 1353-1358.},
Year = {1995},
Key = {fds114914}
}
@article{fds114916,
Title = {Nicolelis MAL, Chapin JK, Lin RCS (1995) Development of
the direct projections from the zona incerta to the primary
somatosensory cortex in rats. Neurosci 65:
609-631.},
Year = {1995},
Key = {fds114916}
}
@article{fds114917,
Title = {Chapin JK, Nicolelis MAL (1995) Beyond single unit
recording: Characterizing neural information in networks of
simultaneously recorded neurons. In: Scale in Conscious
Experience, eds. J. King and K.H. Pribram. Lawrence
Erlbaum Assoc., New Jersey, pp. 133-153.},
Year = {1995},
Key = {fds114917}
}
@article{fds275423,
Author = {Nicolelis, MA and Chapin, JK},
Title = {Spatiotemporal structure of somatosensory responses of
many-neuron ensembles in the rat ventral posterior medial
nucleus of the thalamus.},
Journal = {The Journal of Neuroscience : the Official Journal of the
Society for Neuroscience},
Volume = {14},
Number = {6},
Pages = {3511-3532},
Year = {1994},
Month = {June},
ISSN = {0270-6474},
url = {http://www.ncbi.nlm.nih.gov/pubmed/8207469},
Keywords = {Anesthesia • Animals • Brain Mapping • Cell
Aggregation • Computer Graphics • Evoked
Potentials, Somatosensory* • Neurons • Physical
Stimulation • Rats • Rats, Inbred Strains •
Reaction Time • Thalamic Nuclei • Vibrissae •
Wakefulness • physiology • physiology*},
Abstract = {Classically, the rat ventral posterior medial (VPM) nucleus
of the thalamus has been considered as a simple passive
relay for single-whisker information to the primary
somatosensory cortex (SI). However, recent reports have
suggested that the VPM could contain a much more coarsely
coded and spatiotemporally complex representation of the rat
whisker pad. To address this possibility properly, we have
carried out chronic simultaneous recordings of large numbers
(up to 23) of single neurons, distributed across the entire
VPM, in both awake and lightly anesthetized adult rats.
Quantitative, computer-based reconstruction of receptive
fields (RFs) revealed that single VPM neurons exhibit
significant responses to discrete stimulation of as many as
20 single whiskers (mean +/- SD RF size, 13.7 +/- 4.8
whiskers). By defining multiple response magnitude (RM)
thresholds it was possible to subdivide these large VPM RFs
quantitatively into a prominent center (mean +/- SD, 1.41
+/- 0.70 whiskers, RM > 95%) and an excitatory surround (up
to 18 whiskers, RM < 95%). VPM neurons exhibited both
short-latency responses (SLRs, from 4 to 10 msec
poststimulus) and/or long-latency responses (LLRs, 15-25
msec), each followed by inhibitory responses. Though LLRs
were weaker (mean +/- SD, 47.19 +/- 33.34 Hz) than SLRs
(119.63 +/- 50.12 Hz), they often defined RFs that differed
considerably from those defined by the SLRs of the same
cell. In particular, VPM cells with short-latency RFs
centered in caudal whiskers (e.g., C1, D1, E1) showed a
poststimulus time-dependent shift of these RF centers toward
the rostral whiskers (e.g., C4, D4, E4). These
caudal-to-rostral (C-->RF shifts occurred in neurons with
the largest RFs of our sample (17.2 +/- 2.4 whiskers). On
the other hand, VPM cells with short-latency RFs centered in
rostral whiskers had the smallest RFs (13.1 +/- 4.1
whiskers) and usually did not exhibit time-dependent RF
center shifts. Multivariate analysis revealed that these two
groups of VPM neurons, C-->R shifting and rostral position
(RP) cells, could be statistically distinguished according
to a combination of three RF attributes (short-latency RF
center location, RF size, and magnitude of RF center shift).
Quantitative, computer-based reconstruction of "population
response maps" demonstrated that the "place" coding for each
single whisker in the VPM involved a distinct weighted
contribution from a large proportion of the simultaneously
recorded neurons.(ABSTRACT TRUNCATED AT 400
WORDS)},
Doi = {10.1523/JNEUROSCI.14-06-03511.1994},
Key = {fds275423}
}
@article{fds114871,
Title = {Bennett-Clarke CA, Nicolelis MAL, Jacquin MF (1994)
Proceedings of a satellite symposium of the 1993 Society for
Neuroscience Meeting. Somat Mot Res 11: 197-204.},
Year = {1994},
Key = {fds114871}
}
@article{fds114913,
Title = {Nicolelis MAL, Chapin JK (1994) Spatiotemporal structure of
somatosensory responses of many-neuron ensembles in the rat
ventral posterior medial nucleus of the thalamus. J Neurosci
14: 3511-3532.},
Year = {1994},
Key = {fds114913}
}
@article{fds275409,
Author = {Arends, JJ and Bennett-Clarke, CA and Jacquin, MF and Nicolelis, MA and Shortland, PJ},
Title = {Barrels VI: proceedings of a satellite symposium of the 1993
Society for Neuroscience meeting.},
Journal = {Somatosensory & Motor Research},
Volume = {11},
Number = {3},
Pages = {197-204},
Year = {1994},
ISSN = {0899-0220},
url = {http://www.ncbi.nlm.nih.gov/pubmed/7887052},
Keywords = {Age Factors • Animals • Brain Mapping •
Cerebral Cortex • Neural Pathways • Rats •
Somatosensory Cortex • Thalamic Nuclei •
Trigeminal Nuclei • Vibrissae • innervation*
• physiology • physiology*},
Doi = {10.3109/08990229409051388},
Key = {fds275409}
}
@article{fds275438,
Author = {Nicolelis, MA and Lin, RC and Woodward, DJ and Chapin,
JK},
Title = {Dynamic and distributed properties of many-neuron ensembles
in the ventral posterior medial thalamus of awake
rats.},
Journal = {Proceedings of the National Academy of Sciences of the
United States of America},
Volume = {90},
Number = {6},
Pages = {2212-2216},
Year = {1993},
Month = {March},
ISSN = {0027-8424},
url = {http://www.ncbi.nlm.nih.gov/pubmed/8460124},
Keywords = {Animals • Electrophysiology • Models, Neurological
• Neurons • Physical Stimulation • Rats
• Thalamus • Vibrissae • Wakefulness •
innervation • methods • physiology •
physiology*},
Abstract = {The traditional view that the map of the face in the ventral
posterior medial thalamus (VPM) is static and highly
discrete was derived largely from qualitative studies that
reported only small, robust, and nonoverlapping receptive
fields (RFs). Here, by using more quantitative techniques,
we have provided evidence for an alternative hypothesis: the
RFs in the VPM are large and overlapping and tend to shift
as a function of post-stimulus time. These results were
obtained through simultaneous recordings of up to 23 single
neurons across the whisker representation in the VPM of
rats. Under both awake and anesthetized conditions, these
neurons responded robustly at short (4-6 ms) and/or long
(15-25 ms) latencies to discrete vibromechanical stimulation
of single facial whiskers. Computer graphics were used to
construct three-dimensional plots depicting the magnitudes
of neuronal responses to stimulation of each of several
whiskers as a function of post-stimulus time. These
"spatiotemporal RFs" demonstrated that (i) the RFs of VPM
neurons are quite large, covering up to 20 whiskers and (ii)
the spatial locations of these RFs may shift dramatically
over the first 35 ms of post-stimulus time, especially from
the caudal-most to the rostral-most whiskers on the face.
These results suggest that the VPM contains a dynamic and
distributed representation of the face, in which stimulus
information is coded in both spatial and temporal
domains.},
Doi = {10.1073/pnas.90.6.2212},
Key = {fds275438}
}
@article{fds275406,
Author = {Nicolelis, MA and Lin, RC and Woodward, DJ and Chapin,
JK},
Title = {Induction of immediate spatiotemporal changes in thalamic
networks by peripheral block of ascending cutaneous
information.},
Journal = {Nature},
Volume = {361},
Number = {6412},
Pages = {533-536},
Year = {1993},
Month = {February},
ISSN = {0028-0836},
url = {http://www.ncbi.nlm.nih.gov/pubmed/8429906},
Keywords = {Animals • Evoked Potentials • Lidocaine •
Nerve Net • Neuronal Plasticity • Rats •
Reaction Time • Sensory Deprivation • Thalamus
• pharmacology • physiology •
physiology*},
Abstract = {Peripheral sensory deprivation induces reorganization within
the somatosensory cortex of adult animals. Although most
studies have focused on the somatosensory cortex, changes at
subcortical levels (for example the thalamus) could also
play a fundamental role in sensory plasticity. To
investigate this, we made chronic simultaneous recordings of
large numbers of single neurons across the ventral posterior
medial thalamus (VPM) in adult rats. This allowed a
continuous and quantitative evaluation of the receptive
fields of the same sample of single VPM neurons per animal,
before and after sensory deprivation. Local anaesthesia in
the face induced an immediate and reversible reorganization
of a large portion of the VPM map. This differentially
affected the short latency (4-6 ms) responses (SLRs) and
long latency (15-25 ms) responses (LLRs) of single VPM
neurons. The SLRs and LLRs normally define spatiotemporally
complex receptive fields in the VPM. Here we report that 73%
of single neurons whose original receptive fields included
the anaesthetized zone showed immediate unmasking of SLRs in
response to stimulation of adjacent cutaneous regions,
and/or loss of SLRs with preservation or enhancement of LLRs
in response to stimulation of regions just surrounding the
anaesthetized zone. This thalamic reorganization
demonstrates that peripheral sensory deprivation may induce
immediate plastic changes at multiple levels of the
somatosensory system. Further, its spatiotemporally complex
character suggests a disruption of the normal dynamic
equilibrium between multiple ascending and descending
influences on the VPM.},
Doi = {10.1038/361533a0},
Key = {fds275406}
}
@article{fds114869,
Title = {Nicolelis MAL, Lin RCS, Woodward DJ, Chapin JK (1993)
Peripheral block of ascending cutaneous information induces
immediate spatiotemporal changes in thalamic networks.
Nature 361: 533-536.},
Year = {1993},
Key = {fds114869}
}
@article{fds114912,
Title = {Nicolelis MAL, Lin RCS, Woodward DJ, Chapin JK (1993)
Dynamic and distributed properties of many-neuron ensembles
in the ventral posterior medial (VPM) thalamus of awake
rats. Proc Natl Acad Sci USA 90: 2212-2216.},
Year = {1993},
Key = {fds114912}
}
@article{fds275405,
Author = {Nicolelis, MA and Chapin, JK and Lin, RC},
Title = {Somatotopic maps within the zona incerta relay parallel
GABAergic somatosensory pathways to the neocortex, superior
colliculus, and brainstem.},
Journal = {Brain Research},
Volume = {577},
Number = {1},
Pages = {134-141},
Year = {1992},
Month = {April},
ISSN = {0006-8993},
url = {http://www.ncbi.nlm.nih.gov/pubmed/1521138},
Keywords = {Afferent Pathways • Animals • Brain Mapping •
Brain Stem • Cerebral Cortex •
Immunohistochemistry • Rats • Somatosensory Cortex
• Superior Colliculus • Thalamus • anatomy &
histology • anatomy & histology* •
gamma-Aminobutyric Acid • methods* •
physiology*},
Abstract = {Neurons located in the zona incerta (ZI) of the ventral
thalamus project to several regions of the central nervous
system, including the neocortex, superior colliculus, and
brainstem. However, whether these projections are
functionally segregated remains unknown. This issue was
addressed here by combining neuroanatomical tracers with
immunohistochemical staining for gamma-aminobutyric acid
(GABA) and/or parvalbumin, coupled with neurophysiological
mapping. GABAergic projection neurons were found in four
distinct subregions of the ZI including: (1) the rostral
pole of the ZI, from which neurons project to the
supragranular layers of the neocortex (especially layer I);
(2) the dorsal subregion of the ZI, where both ascending
projections to the neocortex and descending projections to
the pretectal area were observed; (3) the ventral subregion
of the ZI, whose neurons project to the superior colliculus;
and 3) the caudal pole of the ZI, from which descending
projections to the lower brainstem and spinal cord were
observed. Somatotopic representations of the contralateral
cutaneous periphery were also identified in the dorsal and
ventral subregions of ZI, both of which were found to
receive dense direct afferent projections from the
trigeminal complex, and dorsal column nuclei. These results
suggest that the rat ZI is a major somatosensory relay in
the ventral thalamus, carrying feed-forward inhibitory
signals to neocortical and subcortical targets, in parallel
with the excitatory somatosensory pathways.},
Doi = {10.1016/0006-8993(92)90546-l},
Key = {fds275405}
}
@article{fds275448,
Author = {Nicolelis, MA and Chapin, JK and Lin, RC},
Title = {Neonatal whisker removal in rats stabilizes a transient
projection from the auditory thalamus to the primary
somatosensory cortex.},
Journal = {Brain Research},
Volume = {567},
Number = {1},
Pages = {133-139},
Year = {1991},
Month = {December},
ISSN = {0006-8993},
url = {http://www.ncbi.nlm.nih.gov/pubmed/1726139},
Keywords = {Aging • Animals • Animals, Newborn • Auditory
Cortex • Axonal Transport • Fluorescent Dyes
• Functional Laterality • Rats •
Somatosensory Cortex • Thalamus • Vibrissae •
anatomy & histology • growth & development •
innervation • physiology*},
Abstract = {A normally transient cross-modal thalamocortical projection
from the magnocellular subdivision of the medial geniculate
nucleus (MGm) to the primary somatosensory (SI) cortex of
rats was found to remain unchanged throughout adulthood
following unilateral removal of whiskers in newborn animals.
The normal MGm projection to the auditory cortex is not lost
in these neonatally whisker-deprived adults rats but some of
the MGm neurons send collaterals to both primary auditory
and SI cortices. Parallel electrophysiological experiments
demonstrated the multimodal character of some MGm neurons,
since they responded to both auditory and cutaneous
stimulation. These results suggest that the areal
distribution in the cortex of thalamocortical projections
arising from a multimodal thalamic nucleus, such as the MGm,
may be determined during early postnatal development by the
normal flow of sensory information from the periphery to the
thalamus and that an early postnatal somatosensory
deprivation may prevent the normal withdrawal of a
cross-modal projection from the MGm to the
SI.},
Doi = {10.1016/0006-8993(91)91445-7},
Key = {fds275448}
}
@article{fds275440,
Author = {Nicolelis, MA and Chapin, JK and Lin, RC},
Title = {Thalamic plasticity induced by early whisker removal in
rats.},
Journal = {Brain Research},
Volume = {561},
Number = {2},
Pages = {344-349},
Year = {1991},
Month = {October},
ISSN = {0006-8993},
url = {http://www.ncbi.nlm.nih.gov/pubmed/1802348},
Keywords = {Aging • Animals • Animals, Newborn •
Mechanoreceptors • Neuronal Plasticity* • Neurons
• Rats • Rats, Inbred Strains • Reference
Values • Skin • Thalamus • Vibrissae •
growth & development • innervation* • physiology
• physiology*},
Abstract = {Neurophysiological mapping was used to study the effects of
early postnatal removal of mystacial whiskers on the
organization of cutaneous receptive fields (RFs) within the
ventral posterior thalamus (VP) of rats. This sensory
deprivation induced an extensive reorganization of the
thalamus, as reflected in larger facial or continuous
overlapping face-body RFs and a higher proportion of
slowly-adapting responses. Mapping of the VP of young rats
(2-3 weeks old) demonstrated that the functional
organization of the immature VP thalamus resembles that of
the sensory-deprived VP, suggesting that an early postnatal
sensory deprivation may interfere with the normal process of
thalamic development.},
Doi = {10.1016/0006-8993(91)91614-7},
Key = {fds275440}
}
@article{fds275436,
Author = {Lin, CS and Nicolelis, MA and Schneider, JS and Chapin,
JK},
Title = {GABAergic pathway from zona incerta to neocortex:
clarification.},
Journal = {Science (New York, N.Y.)},
Volume = {251},
Number = {4998},
Pages = {1162},
Year = {1991},
Month = {March},
ISSN = {0036-8075},
url = {http://www.ncbi.nlm.nih.gov/pubmed/1706534},
Keywords = {Animals • Axonal Transport • Cerebral Cortex
• Diencephalon • Horseradish Peroxidase •
Mice • Neurons • Rats • Thalamus •
anatomy & histology* • cytology •
gamma-Aminobutyric Acid • physiology*},
Doi = {10.1126/science.251.4998.1162-c},
Key = {fds275436}
}
@article{fds275445,
Author = {Baccala, LA and Nicolelis, MA and Yu, CH and Oshiro,
M},
Title = {Structural analysis of neural circuits using the theory of
directed graphs.},
Journal = {Computers and Biomedical Research, an International
Journal},
Volume = {24},
Number = {1},
Pages = {7-28},
Year = {1991},
Month = {February},
ISSN = {0010-4809},
url = {http://www.ncbi.nlm.nih.gov/pubmed/2004525},
Keywords = {Animals • Models, Biological* • Nerve Net •
Software • Vertebrates • physiology*},
Abstract = {A new approach to analysis of structural properties of
biological neural circuits is proposed based on their
representation in the form of abstract structures called
directed graphs. To exemplify this methodology, structural
properties of a biological neural network and randomly wired
circuits (RC) were compared. The analyzed biological circuit
(BC) represented a sample of 39 neural nuclei which are
responsible for the control of the cardiovascular function
in higher vertebrates. Initially, direct connections of both
circuits were stored in a square matrix format. Then,
standard algorithms derived from the theory of directed
graphs were applied to analyze the pathways of the circuits
according to their length (in number of synapses), degree of
connectedness, and structural strength. Thus, the BC was
characterized by the presence of short, reciprocal, and
unidirectional pathways which presented a high degree of
heterogeneity in their strengths. This heterogeneity was
mainly due to the existence of a small cluster of
reciprocally connected neural nuclei in the circuit that
have access, through short pathways, to most of the network.
On the other hand, RCs were characterized by the presence of
long and mainly reciprocal pathways which showed lower and
absolute homogeneous strengths. Through this study the
proposed methodology was demonstrated to be a simple and
efficient way to store, analyze, and compare basic
neuroanatomical information.},
Doi = {10.1016/0010-4809(91)90010-t},
Key = {fds275445}
}
@article{91041073877,
Author = {Sabin, AB and Beckwith, J and Poritz, MA and Bernstein, HD and Walter,
P and Hardin, G and Meier, P and Hart, H and Lin, C-S and Nicolelis, MAL and Schneider, JS and Chapin, JKJ},
Title = {Effectiveness of AIDS vaccines. 'Sequence-Gazing?'. Unus
triginta et quoque anno?. Steroid therapy publication delay.
Buckyballs and double bonds. GABAergic pathway from zona
incerta to neocortex. Clarification},
Journal = {Science},
Volume = {251},
Number = {4998},
Pages = {1161},
Year = {1991},
Key = {91041073877}
}
@article{fds275449,
Author = {Nicolelis, MA and Baccala, LA},
Title = {Rhythmic bacterial susceptibility to antibiotics at a large
hospital.},
Journal = {Journal of Clinical Epidemiology},
Volume = {44},
Number = {2},
Pages = {191-205},
Year = {1991},
ISSN = {0895-4356},
url = {http://www.ncbi.nlm.nih.gov/pubmed/1899881},
Keywords = {Anti-Bacterial Agents • Bacteria • Bacterial
Infections • Cross Infection • Escherichia coli
• Humans • Klebsiella pneumoniae • Proteus
mirabilis • Pseudomonas aeruginosa • Species
Specificity • Staphylococcus aureus • drug effects
• drug effects* • microbiology* •
pharmacology*},
Abstract = {The in vitro susceptibility response of Staphylococcus
aureus, Klebsiella pneumoniae, Escherichia coli, Proteus
mirabilis and Pseudomonas aeruginosa to a set of antibiotics
was investigated in a survey comprising 19,380 positive
cultures over a period of 5 years in a large hospital
environment. Four out of the five species (P. aeruginosa
being the exception) presented a species-specific,
drug-independent, rhythmic variation of their level of
susceptibility to several antibiotics over the time of the
study. The species-specific rhythmic responses were further
characterized by spectral analysis, autocorrelation and
cross-correlation functions. Through this analysis it was
possible to rank the species according to their main period
of oscillation. The longest period of oscillation was
detected for S. aureus (38 months). K. pneumoniae and E.
coli presented intermediate values (25 and 23 months
respectively), and P. mirabilis the shortest period of
oscillation (11 months). Species displaying long periods of
oscillation tended to present very low levels of
susceptibility, while species displaying short periods of
oscillation usually presented the highest levels of
susceptibility observed. Although some hospital
environmental factors, such as drug consumption, were also
analyzed, no correlation was found between them and the in
vitro bacterial cyclic responses to antibiotics.},
Doi = {10.1016/0895-4356(91)90266-c},
Key = {fds275449}
}
@article{fds275452,
Author = {Nicolelis, MA and Chapin, JK and Lin, CS},
Title = {Ontogeny of corticocortical projections of the rat
somatosensory cortex.},
Journal = {Somatosensory & Motor Research},
Volume = {8},
Number = {3},
Pages = {193-200},
Year = {1991},
ISSN = {0899-0220},
url = {http://www.ncbi.nlm.nih.gov/pubmed/1767617},
Keywords = {Aging • Animals • Caudate Nucleus • Cerebral
Cortex • Corpus Callosum • Dominance, Cerebral
• Neural Pathways • Neurons • Putamen •
Rats • Somatosensory Cortex • Thalamic Nuclei
• anatomy & histology • anatomy & histology*
• physiology* • ultrastructure},
Abstract = {Rhodamine-coated microspheres (RCMs) were injected into the
primary somatosensory cortex (SI) of rats ranging in age
from postnatal (PN) day 1 to adulthood. Ipsilateral
corticocortical and callosal projections within the SI were
identified as early as PN day 1. At the end of the first PN
week, ipsilaterally projecting neurons located in sublayer
VIb were the first to assume an adult-like pattern of
connectivity. Injections at subsequent postnatal ages
revealed that an adult pattern of lamination of ipsilateral
corticocortical projections within the SI is established
between PN weeks 2 and 3, comprising projection neurons from
layers II/III, layer V, and sublayer VIb. Therefore, local
interactions in the rat SI are mediated not only by
pyramidal neurons of layers III and V, derived from the
cortical plate, but also by a subpopulation of
ontogenetically older neurons located in the sublayer VIb,
which may correspond to the subplate neurons of other
species. Overall, these results suggest the existence of
three independent short-range corticocortical systems of
projections within the rat SI, which differ in terms of the
laminar distribution and ontogenetic origin of their
cells.},
Doi = {10.3109/08990229109144743},
Key = {fds275452}
}
@article{fds275399,
Author = {Lin, CS and Nicolelis, MA and Schneider, JS and Chapin,
JK},
Title = {A major direct GABAergic pathway from zona incerta to
neocortex.},
Journal = {Science (New York, N.Y.)},
Volume = {248},
Number = {4962},
Pages = {1553-1556},
Year = {1990},
Month = {June},
ISSN = {0036-8075},
url = {http://www.ncbi.nlm.nih.gov/pubmed/2360049},
Keywords = {Animals • Cerebral Cortex • Diencephalon •
Dopamine • Glutamate Decarboxylase •
Immunohistochemistry • Neural Pathways • Neurons
• Rats • analysis • enzymology •
gamma-Aminobutyric Acid • physiology •
physiology*},
Abstract = {Retrograde fluorescent tracers were used to demonstrate a
previously unknown but sizable direct gamma-aminobutyric
acid (GABA)-containing neuronal pathway from the zona
incerta to the neocortex in rats. This incertocortical
pathway was found to project bilaterally to the entire
neocortex and exhibited a rough corticotopic organization.
Many of the zona incerta neurons projecting to the parietal
and occipital cortices could also be immunohistochemically
stained with antibodies to glutamic acid decarboxylase and
GABA. Few of these neurons were immunoreactive to tyrosine
hydroxylase antibodies, which identify dopamine-containing
neurons. Injections in the frontal and entorhinal cortices
labeled many neurons near or within the dopaminergic A13
subdivision of the zona incerta. In addition, the
incertocortical system was found to be significantly larger
during early postnatal (2 to 3 weeks) development. The
projection pattern of this newly discovered pathway
resembles that of the monoaminergic and cholinergic systems,
arising from the brainstem and forebrain, suggesting
possible similarities of function.},
Doi = {10.1126/science.2360049},
Key = {fds275399}
}
@article{fds275420,
Author = {Nicolelis, MA and Tinone, G and Sameshima, K and Timo-Iaria, C and Yu,
CH and Van de Bilt and MT},
Title = {Connection, a microcomputer program for storing and
analyzing structural properties of neural
circuits.},
Journal = {Computers and Biomedical Research, an International
Journal},
Volume = {23},
Number = {1},
Pages = {64-81},
Year = {1990},
Month = {February},
ISSN = {0010-4809},
url = {http://www.ncbi.nlm.nih.gov/pubmed/2306935},
Keywords = {Algorithms • Cardiovascular System • Information
Systems • Microcomputers* • Models, Neurological*
• Neural Pathways • Software Design •
Software* • anatomy & histology* •
innervation*},
Abstract = {The application of a microcomputer-based system (the
Connection system) designed to deal with neuroanatomical
information commonly analyzed by researchers and involved in
the study of structural properties of neural circuits is
presented. This system can be employed at first as a
readily-accessible database containing physiological and
anatomical data from nuclei of the central nervous system
which define a network with up to 45 elements and their
subdivisions and connections. Once the database from a
specific network is built and stored in a file, routines of
this system can be used to classify the nuclei in term of
their afferents and efferents and also to display all
possible pathways linking any pair of nuclei and their
respective length (number of synapses). The role of such a
system as an auxiliary tool in neuroanatomical and
electrophysiological research is discussed by presenting the
results obtained from the analysis of the neural circuits
involved in cardiovascular function control in higher
vertebrates.},
Doi = {10.1016/0010-4809(90)90007-y},
Key = {fds275420}
}
@article{fds114911,
Title = {Lin CS, Nicolelis MAL, Schneider JS, Chapin JK (1990) A
major direct GABAergic pathway from zona incerta to
neocortex. Science 248: 1553-1556.},
Year = {1990},
Key = {fds114911}
}
@article{fds275418,
Author = {Nicolelis, MA and Yu, CH and Baccala, LA},
Title = {Structural characterization of the neural circuit
responsible for control of cardiovascular functions in
higher vertebrates.},
Journal = {Computers in Biology and Medicine},
Volume = {20},
Number = {6},
Pages = {379-400},
Year = {1990},
ISSN = {0010-4825},
url = {http://www.ncbi.nlm.nih.gov/pubmed/2286073},
Keywords = {Animals • Cardiovascular System • Cluster Analysis
• Computer Simulation* • Microcomputers •
Models, Biological* • Nerve Net • Vertebrates
• innervation* • physiology*},
Abstract = {A comparison of structural properties of a biological neural
system responsible for cardiovascular function control in
higher vertebrates with randomly connected networks was
pursued using matrix representations of those circuits. The
biological circuit was characterized by the presence of some
heavily connected nuclei in contrast to the random networks
that had equally distributed connections between their
elements. This property of the analysed biological circuit
was shown to account for a high logarithmic correlation
found between two indexes defined to represent pointwise
features of the nuclei and their global contribution to the
whole network. The first index is obtained by the product of
the number of inputs and of outputs of a nucleus and was
called power index (PI). The second one, called occurrence
index (OI), defines how many times a specific nucleus is
crossed when all possible pathways joining two nuclei of the
circuit are obtained. This PI-OI correlation was clearly
dependent on the pathway length distribution (expressed in
number of synapses), and was maximal considering pathways
with a low number of synapses. When randomly connected
circuits were analysed lower correlation was found between
the same two indexes and only for much longer pathways.
Therefore, it is proposed that the analysis of the PI-OI
correlation can be useful to quantify structural differences
between biological neural circuits as distinguished from
randomly connected networks and also between neural systems
at different levels of phylogenetic and ontogenetic
development.},
Doi = {10.1016/0010-4825(90)90019-l},
Key = {fds275418}
}
@article{90096090667,
Author = {Baccala, LA and Nicolelis, MAL},
Title = {Using computers to survey the epidemiological, environmental
and genetic factors involved in the process of bacteria
resistance acquisition},
Journal = {Proceedings Annual Symposium on Computer Applications in
Medical Care},
Pages = {261-265},
Address = {Washington, DC, USA},
Year = {1989},
Month = {December},
Keywords = {Statistical Methods--Time Series Analysis;Computer Aided
Analysis--Medical Applications;Genetic Engineering;Information
Theory;Spectrum Analysis;},
Abstract = {The sensitivity behaviors in time of several species (S.
aureus, E. coli, K. pneumoniae, and P. mirabilis in a total
of 16,334 positive cultures collected at the authors'
hospital from July 1981 to December 1986) to amikacin and
gentamicin are shown to be periodic. The implications of
this finding and parameters, both epidemiological and
genetic, that might be of relevance in its understanding are
discussed as being necessary characteristics of a nosocomial
survey-and-control computer system in which time-series
analysis techniques are of central importance.},
Key = {90096090667}
}
@article{fds275242,
Author = {Montes, GS and Nicolelis, MAL and Brentani-Samaia, HP and Furuie,
SS},
Title = {Collagen fibril diameters in arteries of
mice},
Journal = {Cells, Tissues, Organs},
Volume = {135},
Number = {1},
Pages = {57-61},
Publisher = {S. Karger AG},
Year = {1989},
Month = {January},
ISSN = {1422-6405},
url = {http://dx.doi.org/10.1159/000146723},
Abstract = {Arteries of mice were studied by a silver impregnation
technique, by the Picrosirius-polarization method and by
transmission electron microscopy. The histochemical results
obtained coincided with the electron-microscopic
observations in showing the presence of two distinct
collagen populations, segregated into different compartments
of each artery. The fibrous component of the tunica media
was comprised of reticulin fibers, which displayed a
distinct argyrophilia when studied by means of the silver
impregnation technique, and showed up as thin, weakly
birefringent. greenish fibers when examined with the aid of
the Picrosirius-polarization method. In addition, the
electron-microscopic studies disclosed the presence of thin
collagen fibrils in the tunica media, contrasting with the
thicker fibrils that could be localized ultrastructurally to
the tunica adventitia where nonargyrophil, coarse collagen
fibers had been characterized by the histochemical methods
used. In this respect, collagen distribution in arteries of
mice is very similar to the pattern that was consistently
observed in the other species studied, which argues in favor
of the existence of a uniform structural pattern of collagen
distribution that is a general phenomenon in vertebrate
arteries.Experimental results comparing the traditional
method and the computer-aided measurement of collagen fibril
diameters showed that the system provides results equivalent
to those produced by manual execution. In addition, the
advantage in speed of the computer-aided method should prove
useful in complicated studies where numerous structures are
involved. © 1989 S. Karger AG, Basel.},
Doi = {10.1159/000146723},
Key = {fds275242}
}
@article{fds275412,
Author = {Montes, GS and Nicolelis, MA and Brentani-Samaia, HP and Furuie,
SS},
Title = {Collagen fibril diameters in arteries of mice. A comparison
of manual and computer-aided morphometric
analyses.},
Journal = {Acta Anatomica},
Volume = {135},
Number = {1},
Pages = {57-61},
Year = {1989},
ISSN = {0001-5180},
url = {http://www.ncbi.nlm.nih.gov/pubmed/2750461},
Keywords = {Animals • Arteries • Collagen • Female •
Histocytochemistry • Image Processing,
Computer-Assisted* • Male • Mice •
Microscopy, Electron • ultrastructure*},
Abstract = {Arteries of mice were studied by a silver impregnation
technique, by the Picrosirius-polarization method and by
transmission electron microscopy. The histochemical results
obtained coincided with the electron-microscopic
observations in showing the presence of two distinct
collagen populations, segregated into different compartments
of each artery. The fibrous component of the tunica media
was comprised of reticulin fibers, which displayed a
distinct argyrophilia when studied by means of the silver
impregnation technique, and showed up as thin, weakly
birefringent, greenish fibers when examined with the aid of
the Picrosirius-polarization method. In addition, the
electron-microscopic studies disclosed the presence of thin
collagen fibrils in the tunica media, contrasting with the
thicker fibrils that could be localized ultrastructurally to
the tunica adventitia where nonargyrophil, coarse collagen
fibers had been characterized by the histochemical methods
used. In this respect, collagen distribution in arteries of
mice is very similar to the pattern that was consistently
observed in the other species studied, which argues in favor
of the existence of a uniform structural pattern of collagen
distribution that is a general phenomenon in vertebrate
arteries. Experimental results comparing the traditional
method and the computer-aided measurement of collagen fibril
diameters showed that the system provides results equivalent
to those produced by manual execution. In addition, the
advantage in speed of the computer-aided method should prove
useful in complicated studies where numerous structures are
involved.},
Key = {fds275412}
}
@article{89095041155,
Author = {Nicolelis, MAL and Yu, CH},
Title = {Defining criteria for quantitative analysis of the neural
network responsible for the cardiovascular function control
by means of a microcomputer system},
Journal = {Proceedings Annual Symposium on Computer Applications in
Medical Care},
Pages = {256-260},
Address = {Washington, DC, USA},
Year = {1988},
Month = {November},
Keywords = {Computer Software--Medical Applications;Systems Science and
Cybernetics--Neural Nets;Computers, Microcomputer--Medical
Applications;},
Abstract = {Software designed to deal with information from pathways
connecting nuclei of the central nervous system was used to
study the neural network related to the cardiovascular
control in high vertebrates. The 39 most-cited nuclei in the
literature and 123 links between pairs of nuclei were
considered. Four anatomical indexes were tested as
quantitative parameters of the network. The power index,
which is the product of the inputs and outputs of a nucleus,
was the best in selecting a small set of structures of this
network. This set turned to be the major cluster of nuclei
involved in the neural control of the cardiovascular
function as described in the literature. This index was also
an estimator of the nucleus participation in nuclei. These
results suggest a close relationship between anatomical
properties and physiological function of the nuclei involved
in this network.},
Key = {89095041155}
}
@article{fds275443,
Author = {Nicolelis, MA and Baccala, LA},
Title = {Do bacteria have an intrinsic rhythmic sensitivity
pattern?},
Journal = {Critical Care Medicine},
Volume = {16},
Number = {6},
Pages = {650},
Year = {1988},
Month = {June},
ISSN = {0090-3493},
url = {http://www.ncbi.nlm.nih.gov/pubmed/3371037},
Keywords = {Microbial Sensitivity Tests* • Periodicity},
Doi = {10.1097/00003246-198806000-00023},
Key = {fds275443}
}
@article{fds275400,
Author = {Nicolelis, MA and Baccala, LA},
Title = {Time series analysis of rhythmic bacterial resistance
development to antibiotics.},
Journal = {Computers and Biomedical Research, an International
Journal},
Volume = {21},
Number = {2},
Pages = {137-157},
Year = {1988},
Month = {April},
ISSN = {0010-4809},
url = {http://www.ncbi.nlm.nih.gov/pubmed/3286102},
Keywords = {Analysis of Variance • Data Interpretation,
Statistical* • Drug Resistance, Microbial* •
Escherichia coli • Fourier Analysis • Periodicity*
• Staphylococcus aureus • Time Factors • drug
effects},
Abstract = {The sensitivity data of Staphylococcus aureus and
Escherichia coli to a large set of antibiotics have
undergone time series procedures of analysis in order to
highlight possibly periodical behavior in time. These
oscillational patterns have been characterized through the
use of FFT and cross-correlational and variance analysis and
were proved to be species-specific and drug-independent. S.
aureus was shown to have a large period of oscillation (40
months) when compared to E. coli (from 7 to 11 months). A
perfect species distinction was only possible through cross
correlation. These results may reflect the influence of the
local environment, since this finding was not referred to in
the literature.},
Doi = {10.1016/0010-4809(88)90022-5},
Key = {fds275400}
}
@article{fds275417,
Author = {Nicolelis, MA and Hong, YC},
Title = {Application of a microcomputer-based system in the analysis
of infection data at the emergency units of a large
hospital.},
Journal = {International Journal of Bio Medical Computing},
Volume = {22},
Number = {3-4},
Pages = {183-198},
Year = {1988},
ISSN = {0020-7101},
url = {http://www.ncbi.nlm.nih.gov/pubmed/3045020},
Keywords = {Brazil • Computers* • Cross Infection •
Emergency Service, Hospital* • Escherichia coli
Infections • Hospital Information Systems* •
Humans • Klebsiella Infections • Microbial
Sensitivity Tests • Microcomputers* • Pseudomonas
Infections • Retrospective Studies • Software*
• Staphylococcal Infections • epidemiology •
epidemiology* • microbiology},
Abstract = {After three years of retrospective study in four emergency
units from a large hospital (2000 beds) and analysis of 6283
positive cultures, a microcomputer database system was built
to store information concerning nosocomial infections in
order to help the clinical staff from those units to study
the incidence of 20 bacterial species and their sensitivity
pattern evolutions for 27 antibiotics (from samples in 15
different collecting sites). This system was developed as an
alternative to the hospital mainframe computer
microbiological reports. It put emphasis on graphical
outputs instead of the coded tables generated by the bigger
system. This orientation and the possibility of sectorial
infection data analysis were responsible for the general
acceptance of the microcomputer-based system by the clinical
staff. As the first practical results, the system was able
to detect a particular increase in the incidence of
Staphylococcus aureus in surgical emergency units (up to
21.6% in 1982) as well as the dissemination of the
antimicrobial resistance patterns of S. aureus and
Klebsiella pneumoniae from the surgical units to the
clinical ones. The time evolution behaviour of Pseudomonas
aeruginosa, Escherichia coli and other nonfermentative Gram
negative bacilli was also studied to complete the analysis
of the most pathogenic bacterial species found in our
emergency units.},
Doi = {10.1016/0020-7101(88)90073-6},
Key = {fds275417}
}
@article{89044190309,
Author = {Lage, SG and Gutierrez, MA and Nicolelis, MAL and Furuie,
SS},
Title = {Bedside computerized system for monitoring and processing of
biological signals in intensive care units},
Journal = {Computers in Cardiology},
Pages = {561-564},
Address = {Louvain-La-Neuve, Belg},
Year = {1987},
Month = {December},
Keywords = {BIOMEDICAL ENGINEERING -- Patient Monitoring;SIGNAL
PROCESSING -- Digital Techniques;WAVEFORM ANALYSIS;COMPUTER
AIDED ANALYSIS;},
Abstract = {A description is given of the application of a generic
bedside system, developed using an IBM-PC compatible, with
the aim of getting essential biological signals to perform a
complete cardiovascular function analysis. Six cardiac
patients with critical heart failure impaired by arrhythmia,
infection, pulmonary embolism and myocardial infarction were
monitored through: (a) ECG; (b) VCG; (c) hemodynamic data
(right atrial pressure, pulmonary arterial pressure,
pulmonary wedge pressure, systemic pressure); (d) cardiac
output (thermodilution and thoracic electrical
bioimpedance); (e) dZ/dt of TEB. These signals were stored
and processed to furnish the electrical-hemodynamic coupling
correlation. As a control, the results of the cardiac output
calculated by TEB were compared to the thermodilution
method. The dZ/dt wave together with the ECG and hemodynamic
signals allowed continuous determination of the pre-ejection
period, ventricular ejection time, isovolumetric relaxation,
time and ventricular filling period. The system also
permitted several devices to be interfaced to the
microcomputer, a better therapeutic approach for critical
patients, as well as providing data for medical education
and research.},
Key = {89044190309}
}
@article{89044190294,
Author = {Gutierrez, MA and Furuie, SS and Nicolelis, MAL and Lage,
S},
Title = {Developing a multi-purpose microcomputer-based system for
biological signal analysis for cardiovascular
protocols},
Journal = {Computers in Cardiology},
Pages = {505-508},
Address = {Louvain-La-Neuve, Belg},
Year = {1987},
Month = {December},
Keywords = {COMPUTER AIDED ANALYSIS -- Medical Applications;HOSPITALS --
Intensive Care Units;WAVEFORM ANALYSIS;},
Abstract = {A description is given of the development of a general
microcomputer-based system to perform biological signal
processing concerning clinical and experimental protocols in
cardiology. At intensive care units the software of this
system enabled the clinical staff to acquire several signals
simultaneously, like the cardiac chamber pressures, arterial
pressure, respiratory flow, ECG, and EEC, and to interface
an IBM PC compatible with other devices (like thoracic
electrical bioimpedance) which can furnish important
ventricular stroke volume mesurements. On the other hand, in
experimental protocols, where the relationship between the
latter signals with action potentials from peripherical
nerves was pursued, it was necessary to design a window
discriminator (WD) that allowed the study of point processes
related to the neural control of the cardiovascular system.
This WD was connected to the microcomputer through the
parallel interface which suffered minor modifications. The
software was divided in modules. To evaluate the signals
after acquisition several basic routines are available
(smoothing, statistical and spectral procedures).},
Key = {89044190294}
}
@article{fds275446,
Author = {Massad, E and Engel, AB and Nicolelis, MA},
Title = {A mathematical model for spirometry.},
Journal = {Computers and Biomedical Research, an International
Journal},
Volume = {20},
Number = {2},
Pages = {105-112},
Year = {1987},
Month = {April},
ISSN = {0010-4809},
url = {http://www.ncbi.nlm.nih.gov/pubmed/3595094},
Keywords = {Animals • Humans • Microcomputers • Models,
Theoretical* • Plethysmography, Whole Body • Rats
• Rats, Inbred Strains • Spirometry*},
Abstract = {A model originally designed to fit population growth data
was investigated to determine whether it could fit
spirometric traces as a function of time in normal and ill
humans and in normal rats, obtained, respectively, by
spirometer and whole-body plethysmography. The model showed
great accuracy when applied to a simple spirometer coupled
with an analog-to-digital converter interfaced with a
personal computer. It also proved to be a good alternative
for the more expensive and less accurate electronic devices,
as derivative systems, and may be an attractive method for
research and/or diagnostic centers.},
Doi = {10.1016/0010-4809(87)90038-3},
Key = {fds275446}
}
@article{fds275407,
Author = {Nicolelis, MA and Massad, E and Hutzler, RU and Engel, A and Rodrigues,
E and Bazzone, JC and Tomida, M},
Title = {Mathematical model of Klebsiella pneumoniae resistance to
amikacin and gentamicin.},
Journal = {Brazilian Journal of Medical and Biological Research =
Revista Brasileira De Pesquisas Medicas E
Biologicas},
Volume = {20},
Number = {1},
Pages = {35-41},
Year = {1987},
ISSN = {0100-879X},
url = {http://www.ncbi.nlm.nih.gov/pubmed/3318975},
Keywords = {Amikacin • Drug Resistance, Microbial •
Gentamicins • Klebsiella pneumoniae • Microbial
Sensitivity Tests • Models, Theoretical • drug
effects* • pharmacology*},
Abstract = {1. The resistance of Klebsiella pneumoniae to amikacin and
gentamicin was studied by a mathematical model to predict
the rate of sensitivity decrease. The results accurately
matched experimental data, showing that the model is a
reliable predicting tool. 2. The observations were carried
out over six years and included 2677 cultures that were
positive for K. pneumoniae. At the beginning of the
observation period, 85.7% of the cultures were sensitive to
amikacin and 40.8% were sensitive to gentamicin. Sensitivity
to amikacin showed a surprisingly rapid decrease; at the end
of the experimental period, amikacin and gentamicin
sensitivities were 33.3% and 27.8%, respectively. 3. We
conclude that patterns of resistance of other bacteria could
be investigated using this method.},
Key = {fds275407}
}
@article{fds275403,
Author = {Nicolelis, MA and Martins, MA and Meireles, LP and Birolini,
D},
Title = {[Analysis of incidence patterns and bacterial sensitivity in
a surgical unit using microcomputers].},
Journal = {Amb; Revista Da Associacao Medica Brasileira},
Volume = {32},
Number = {7-8},
Pages = {134-140},
Year = {1986},
ISSN = {0102-843X},
url = {http://www.ncbi.nlm.nih.gov/pubmed/3494272},
Keywords = {Anti-Bacterial Agents • Bacteria • Computers*
• Cross Infection • Humans • Microbial
Sensitivity Tests* • Microcomputers* • Operating
Rooms* • drug effects* • isolation & purification
• microbiology* • pharmacology*},
Key = {fds275403}
}
@article{fds275401,
Author = {Massad, E and Furuie, SS and Moura Júnior and LDA and Saldiva, PH and Nicolelis, MA and Böhm, GM},
Title = {The use of a personal computer in the pulmonary function
tests of laboratory rats.},
Journal = {Methods of Information in Medicine},
Volume = {24},
Number = {4},
Pages = {197-199},
Year = {1985},
Month = {October},
ISSN = {0026-1270},
url = {http://www.ncbi.nlm.nih.gov/pubmed/4058317},
Keywords = {Animals • Automatic Data Processing* • Computers*
• Microcomputers* • Plethysmography • Rats
• Rats, Inbred Strains • Respiratory Function
Tests • instrumentation*},
Key = {fds275401}
}
@article{fds275402,
Author = {Saldiva, PH and Massad, E and Caldeira, MP and Calheiros, DF and Saldiva, CD and Nicolelis, MA and Böhm, GM},
Title = {Pulmonary function of rats exposed to ethanol and gasoline
fumes.},
Journal = {Brazilian Journal of Medical and Biological Research =
Revista Brasileira De Pesquisas Medicas E
Biologicas},
Volume = {18},
Number = {4},
Pages = {573-577},
Year = {1985},
ISSN = {0100-879X},
url = {http://www.ncbi.nlm.nih.gov/pubmed/2425877},
Keywords = {Animals • Ethanol • Gasoline • Lung •
Male • Petroleum • Rats • Rats, Inbred
Strains • Respiratory Function Tests • Vehicle
Emissions • drug effects* • physiopathology •
toxicity*},
Abstract = {This paper describes the effects of repeated exposure to
gasoline and ethanol exhaust fumes on the pulmonary
mechanics of rats assessed by whole-body plethysmography.
Two groups of 12 male Wistar albino rats each were tested
before and after exposure to diluted gasoline or ethanol
exhaust gases for 5 weeks, 8 h per day and 5 days per week.
An additional group of 12 rats were exposed to clean air
under the same experimental conditions. The variations of
the functional parameters observed in the three groups
before and after exposure were compared. Peak Expiratory
Flow and Forced Expiratory Mean Flows in the ranges 0-25%,
25-50% and 50-75% of Forced Vital Capacity were
significantly reduced in animals exposed to gasoline exhaust
fumes, whereas the group exposed to ethanol exhaust fumes
did not differ from the control group. This respiratory
impairment is probably due to the presence of SO2 and the
quality of the hydrocarbons in gasoline exhaust
gases.},
Key = {fds275402}
}
@article{fds275413,
Author = {Nicolelis, MA and de Carvalho, CR},
Title = {[Standardization of antimicrobial procedures using
computers].},
Journal = {Revista Do Hospital Das Clinicas},
Volume = {40},
Number = {5},
Pages = {227-232},
Year = {1985},
ISSN = {0041-8781},
url = {http://www.ncbi.nlm.nih.gov/pubmed/3836477},
Keywords = {Anti-Bacterial Agents • Bacteria • Computers*
• Cross Infection • Drug Resistance, Microbial
• Humans • Microbial Sensitivity Tests •
Microcomputers* • drug effects* • pharmacology*
• prevention & control • standards*},
Key = {fds275413}
}
%% Books
@book{fds359795,
Author = {Nicolelis, M},
Title = {The true creator of everything: How the human brain shaped
the universe as we know it},
Pages = {1-356},
Year = {2020},
Month = {January},
ISBN = {9780300244632},
Abstract = {A radically new cosmological view from a groundbreaking
neuroscientist who places the human brain at the center of
humanity’s universe Renowned neuroscientist Miguel
Nicolelis introduces a revolutionary new theory of how the
human brain evolved to become an organic computer without
rival in the known universe. He undertakes the first attempt
to explain the entirety of human history, culture, and
civilization based on a series of recently uncovered key
principles of brain function. This new cosmology is centered
around three fundamental properties of the human brain: its
insurmountable malleability to adapt and learn; its
exquisite ability to allow multiple individuals to
synchronize their minds around a task, goal, or belief; and
its incomparable capacity for abstraction. Combining
insights from such diverse fields as neuroscience,
mathematics, evolution, computer science, physics, history,
art, and philosophy, Nicolelis presents a neurobiologically
based manifesto for the uniqueness of the human mind and a
cautionary tale of the threats that technology poses to
present and future generations.},
Key = {fds359795}
}
@book{fds341125,
Author = {Simon, SA and Nicolelis, MAL},
Title = {Series Preface},
Pages = {xii-xiii},
Year = {2011},
Month = {September},
ISBN = {9781439838495},
Key = {fds341125}
}
@book{fds341126,
Author = {Simon, SA and Nicolelis, MAL},
Title = {Neurobiology of Depression},
Pages = {1-481},
Year = {2011},
Month = {September},
ISBN = {9781439838495},
Abstract = {Major depressive disorders have recently been associated
with impairments in signaling pathways that regulate
neuroplasticity and cell survival. Agents designed to
directly target molecules in these pathways hold promise as
new therapeutics for depression. With the collaboration of
the most prestigious international specialists in
biochemistry, molecular biology, genomics, psychiatry,
psychology, and pharmacology, Neurobiology of Depression
discusses the nature of the central nervous system circuits
responsible for the modifications of neuronal functioning
that lead to depression. The book begins by discussing
animal, neurophysiological, and neuropsychological models of
depression as well as neural foundations. It explores
genetic factors that contribute to depression and describes
the effect of monoaminergic systems in the central nervous
system. Next, the book profiles the rise of
psychopharmacology in the treatment of depression and the
research into serotonin and monoamine reuptake inhibitors.
It examines the role of the glutamatergic, endocannabinoid,
and opioid systems in the pathophysiology of mood disorders,
as well as the effect of biological rhythms on the human
body. Later chapters review the role of CRF-related ligands,
CRF receptors, HPA axis activity, and glucocorticoid
receptors in the regulation of the stress response and
depression. They also describe cytokine modulation of
molecular mechanisms. They examine the role of neuropeptide
Y, nitric oxide, beta-arrestins, BDNF, and
phosphodiesterases, and discuss the use of tachykinin
antagonists in treatment. Finally, they analyze the
neurobiological basis for the development of new
antidepressant agents. Exploring myriad aspects of a disease
that plagues a large percentage of the population worldwide,
this volume captures the state of the science of this
debilitating disorder, facilitating further research and
discovery.},
Key = {fds341126}
}
@book{fds340789,
Author = {Simon, SA and Nicolelis, MAL},
Title = {Series preface},
Pages = {xiii},
Year = {2011},
Month = {August},
ISBN = {9781439812174},
Key = {fds340789}
}
@book{fds340156,
Author = {Simon, SA and Nicolelis, MAL},
Title = {Series preface},
Pages = {ix},
Year = {2009},
Month = {January},
ISBN = {9781420076257},
Key = {fds340156}
}
@book{fds340157,
Author = {Simon, SA and Nicolelis, MAL},
Title = {Series preface},
Pages = {xv-xvi},
Year = {2009},
Month = {January},
ISBN = {9781138116047},
Key = {fds340157}
}
@book{fds340158,
Author = {Simon, SA and Nicolelis, MAL},
Title = {Series preface},
Pages = {xi-xiii},
Year = {2008},
Month = {January},
ISBN = {9781420044140},
Key = {fds340158}
}
@book{fds340180,
Author = {Simon, SA and Nicolelis, MAL},
Title = {Series preface},
Pages = {ix-ix},
Year = {2007},
Month = {January},
ISBN = {9780849393624},
Key = {fds340180}
}
@book{fds341127,
Author = {Simon, SA and Nicolelis, MAL},
Title = {Series preface},
Pages = {xi},
Year = {2007},
Month = {January},
ISBN = {9780849370465},
Key = {fds341127}
}
@book{fds340159,
Author = {Nicolelis, MAL},
Title = {Methods for neural ensemble recordings, second
edition},
Pages = {1-287},
Year = {2007},
Month = {January},
ISBN = {9780849370465},
Abstract = {In the last ten years neural ensemble recording grew into a
well-respected and highly data-lucrative science. New
experimental paradigms, including the fabrication of
high-density microelectrodes, new surgical implantation
techniques, multi-channel signal processing, and the
establishment of direct real-time brain-machine interfaces,
hold promise not just for neurophysiology research, but also
for new-generation prosthetic devices aimed at restoring
mobility and communication skills in severely disabled
patients. Extensively updated and expanded, Methods for
Neural Ensemble Recording, Second Edition distills the
current state-of-the-science and provides the nuts and bolts
foundation from which to advance the field for the next ten
years. With contributions from pioneering researchers, this
second edition begins with an overview of microwire array
design for chronic neural recordings. Demonstrating the
diversity now enjoyed in the field, the book reviews new
surgical techniques for chronic implantation of microwire
arrays in not just rodents, but primates as well. It
explores microelectrode microstimulation of brain tissue,
discusses multielectrode recordings in the somatosensory
system and during learning, and analyzes neural ensemble
recordings from the central gustatory-reward pathways in
awake and behaving animals. An exploration of new strategies
for neural ensemble data analysis for Brain-Machine
Interface (BMI) applications foreshadows an investigation
into employing BMI to restore neurological function. Using
multielectrode field potential recordings, contributions
define global brain states and propose conceptual and
technical approaches to human neural ensemble recordings in
the future.},
Key = {fds340159}
}
@book{fds340161,
Author = {Nicolelis, MAL},
Title = {Preface},
Pages = {xiii-xv},
Year = {2007},
Month = {January},
ISBN = {9780849370465},
Key = {fds340161}
}
@book{fds339672,
Author = {Simon, SA and Nicolelis, MAL},
Title = {Series preface},
Pages = {ix},
Publisher = {CRC Press},
Year = {2006},
Month = {January},
ISBN = {9780849342004},
url = {http://dx.doi.org/10.1201/9781420005974},
Doi = {10.1201/9781420005974},
Key = {fds339672}
}
@book{fds340163,
Author = {Simon, SA and Nicolelis, MAL},
Title = {Series preface},
Pages = {v},
Year = {2006},
Month = {January},
ISBN = {0849340756},
Key = {fds340163}
}
@book{fds340164,
Author = {Simon, SA and Nicolelis, MAL},
Title = {Series Preface},
Pages = {ix},
Year = {2005},
Month = {January},
ISBN = {084932131X},
Key = {fds340164}
}
@book{fds341128,
Author = {Simon, SA and Nicolelis, MAL},
Title = {Methods & new frontiers in neuroscience},
Pages = {vii},
Year = {2004},
Month = {January},
ISBN = {9780849315190},
Key = {fds341128}
}
@book{fds340165,
Author = {Simon, SA and Nicolelis, MAL},
Title = {Methods & new frontiers in neuroscience},
Pages = {vii},
Year = {2004},
Month = {January},
ISBN = {0849312876},
Key = {fds340165}
}
@book{fds340167,
Author = {Simon, SA and Nicolelis, MAL},
Title = {Series preface},
Pages = {vii},
Year = {2003},
Month = {January},
ISBN = {0849323924},
Key = {fds340167}
}
@book{fds340168,
Author = {Simon, SA and Nicolelis, MAL},
Title = {Series preface},
Pages = {vii},
Year = {2003},
Month = {January},
ISBN = {0849300975},
Key = {fds340168}
}
@book{fds340169,
Author = {Simon, SA and Nicolelis, MAL},
Title = {Series preface},
Pages = {v},
Year = {2002},
Month = {January},
ISBN = {0849323452},
Key = {fds340169}
}
@book{fds340170,
Author = {Simon, SA and Nicolelis, MAL},
Title = {Series preface},
Pages = {vi},
Year = {2002},
Month = {January},
ISBN = {084930122X},
Key = {fds340170}
}
@book{fds340171,
Author = {Simon, SA and Nicolelis, MAL},
Title = {Methods & new frontiers in neuroscience},
Pages = {vii},
Year = {2001},
Month = {January},
ISBN = {084932386X},
Key = {fds340171}
}
@book{fds340172,
Author = {Simon, SA and Nicolelis, MAL},
Title = {Methods & new frontiers in neuroscience},
Pages = {vii},
Year = {2001},
Month = {January},
ISBN = {0849323975},
Key = {fds340172}
}
@book{fds340173,
Author = {Simon, SA and Nicolelis, MAL},
Title = {Methods and new frontiers in neuroscience},
Pages = {v},
Year = {2000},
Month = {January},
ISBN = {0849322251},
Key = {fds340173}
}
@book{fds340174,
Author = {Simon, SA and Nicolelis, MAL},
Title = {Series Preface},
Pages = {v},
Year = {2000},
Month = {January},
ISBN = {9780849320682},
Key = {fds340174}
}
%% Chapters in Books
@misc{fds337113,
Author = {Nicolelis, MAL},
Title = {The human brain, the true creator of everything, cannot be
simulated by any turing machine},
Pages = {263-269},
Booktitle = {Think Tank: Forty Neuroscientists Explore the Biological
Roots of Human Experience},
Year = {2018},
Month = {April},
ISBN = {9780300225549},
Key = {fds337113}
}
@misc{fds362113,
Author = {Simon, SA and Nicolelis, MAL},
Title = {Frontiers in neuroscience},
Pages = {xv-xv},
Booktitle = {Alzheimer's Disease: Targets for New Clinical Diagnostic and
Therapeutic Strategies},
Year = {2012},
Month = {April},
ISBN = {9781439827086},
Key = {fds362113}
}
@misc{fds341015,
Author = {Lebedev, MA and Crist, RE and Nicolelis, MAL},
Title = {Building brain-machine interfaces to restore neurological
functions},
Pages = {219-240},
Booktitle = {Methods for Neural Ensemble Recordings, Second
Edition},
Year = {2007},
Month = {January},
ISBN = {9780849370465},
Abstract = {Modern research on brain-machine interfaces (BMI) is a
highly multidisciplinary field that has been developing at a
stunning pace since the first experiment conducted 8 years
ago that demonstrated direct control of a robotic
manipulator by ensembles of neurons recorded in cortical and
subcortical areas in awake, behaving rats (Chapin, Moxon et
al. 1999). Since this pioneering study, an exponentially
growing stream of research publications has provoked an
enormous interest in BMIs among scientists from different
fields and the lay public. This level of interest stems from
both the use of BMIs to investigate the way large and
distributed neural circuits operate in behaving animals and
the perceived potential that BMI technology can realize for
restoration of motor behaviors and other functions in
patients suffering from devastating neurological
conditions.},
Key = {fds341015}
}
@misc{fds341016,
Author = {Oliveira-Maia, AJ and Simon, SA and Nicolelis,
MAL},
Title = {Neural ensemble recordings from central gustatory-reward
pathways in awake and behaving animals},
Pages = {189-218},
Booktitle = {Methods for Neural Ensemble Recordings, Second
Edition},
Year = {2007},
Month = {January},
ISBN = {9780849370465},
Abstract = {The mammalian gustatory system participates in the detection
and discrimination of intraoral stimuli, allowing for the
selection of nutrients and rejection of toxic compounds.
However, the sensory percept of a substance that is placed
in the mouth does not depend solely on its taste. The
olfactory and somatosensory systems discriminate odor,
texture, and temperature, which participate, with taste, in
the unitary perception of flavor (Small and Prescott 2005).
Flavor is a central contributor in the decision making
relative to ingestive behavior. However, feeding decisions
are made in specific physiological contexts and, therefore,
are not entirely dependent on sensory experience. We know
today that the central nervous system (CNS) detects a
multitude of peripheral neural and humoral signals that
reflect gastrointestinal status and current energy needs,
availability, and stores (Broberger 2005). The regulation of
energy homeostasis and maintenance of stable body weight
depend on the integration of these signals and the ability
to respond adequately through the modulation of both energy
expenditure and food intake (Schwartz and Porte
2005).},
Key = {fds341016}
}
@misc{fds340160,
Author = {Turner, DA and Patil, PG and Nicolelis, MAL},
Title = {Conceptual and technical approaches to human neural ensemble
recordings},
Pages = {241-258},
Booktitle = {Methods for Neural Ensemble Recordings, Second
Edition},
Year = {2007},
Month = {January},
ISBN = {9780849370465},
Abstract = {The ability to perform either multineuron or local field/EEG
recordings from the nervous system is a critical requirement
to develop a new generation of neuroprosthetics that can
sense the brain’s intent for action (Nicolelis 2001,
2003). This form of sensing neuroprosthesis builds upon the
concept of current neuroprosthetic devices, which are
primarily for macrostimulation of neural elements, such as
deep brain stimulation (DBS); (Abosch, Hutchison et al.
2002; Rodriguez-Oroz, Obeso et al. 2005). A key aspect of
this evolving technology is the translation of preclinical
multineuron recording and analysis technology into the
clinical arena (Donoghue 2002; Carmena, Lebedev et al. 2003;
Mussa-Ivaldi, Miller et al. 2003). This translation requires
the use of medical-grade components at all levels of
electrodes, connections, and electronics, and the
stabilization of technology and software for the long
process of Food and Drug Administration (FDA)
approval.},
Key = {fds340160}
}
@misc{fds340162,
Author = {Lehew, G and Nicolelis, MAL},
Title = {State-of-the-art microwire array design for chronic neural
recordings in behaving animals},
Pages = {1-20},
Booktitle = {Methods for Neural Ensemble Recordings, Second
Edition},
Year = {2007},
Month = {January},
ISBN = {9780849370465},
Abstract = {Over the last two decades, many laboratories around the
world have started to rely on microelectrode arrays formed
by ne microwires, organized in different geometrical
congurations, to chronically record the extracellular
activity of populations of individual neurons in both
anesthetized and behaving animals (Nicolelis et al. 1997,
2003; Lebedev et al. 2006; Verloop and Holsheimer 1984;
Williams et al. 1999). As the eld of chronic multielectrode
recordings evolved, so did the designs of such
microwire-based arrays.},
Key = {fds340162}
}
@misc{fds340871,
Author = {Ribeiro, S and Gervasoni, D and Nicolelis, MAL},
Title = {Neuronal reverberation and the consolidation of new memories
across the wake-sleep cycle},
Pages = {201-223},
Booktitle = {Sleep: Circuits and Functions},
Year = {2004},
Month = {January},
ISBN = {9780849315190},
Abstract = {In mammals and birds, long episodes of nondreaming sleep
(slow-wave sleep, SW) are followed by short episodes of
dreaming sleep (rapid-eye-movement sleep,
REM).},
Key = {fds340871}
}
@misc{fds339862,
Author = {Turner, DA and Dimitrov, DF and Nicolelis, MAL},
Title = {Neuroprosthetics and clinical realization of brain-machine
interfaces},
Pages = {119-139},
Booktitle = {Modern Neurosurgery: Clinical Translation of Neuroscience
Advances},
Year = {2004},
Month = {January},
ISBN = {0849314828},
Abstract = {Neuroprosthetics encompasses a wide variety of interfaces
with the nervous system, usually considered in the context
of clinical abnormalities or disease. The concept stems from
clinical concerns about functional independence and
integration of individuals into society and far-reaching
visions of direct interactions of the brain and mind and
external events.},
Key = {fds339862}
}
@misc{fds339863,
Author = {Turner, DA and Nicolelis, MAL and van Landingham,
K},
Title = {Pre-ictal seizure detection and demand treatment strategies
for epilepsy},
Pages = {105-118},
Booktitle = {Modern Neurosurgery: Clinical Translation of Neuroscience
Advances},
Year = {2004},
Month = {January},
ISBN = {0849314828},
Abstract = {Mechanisms of epilepsy have been explored through a variety
of animal models as well as detailed human studies, for more
than 70 years.1-3 Through the animal models, a large number
of contributing factors leading to epilepsy have been
demonstrated, including conditions that lead to the
intermittent, enhanced synchrony leading to partial or
generalized seizures. While animal models still have only
moderate predictive validity for anticonvulsant therapy
development, the mechanisms may potentially apply to the
human situation. However, in general, most animal models
involve acute seizure development, mirrored in humans as
acute convulsions, usually due to systemic or CNS irritants
or toxins. For example, a classic convulsion may be seen
with an overdose of penicillin or meperidine, and
convulsions are characterized by a high degree of neuronal
electrical synchrony throughout the brain.},
Key = {fds339863}
}
@misc{fds340166,
Author = {Carmena, JM and Nicolelis, MAL},
Title = {Advances in brain-machine interfaces},
Pages = {349-366},
Booktitle = {Motor Cortex in Voluntary Movements: A Distributed System
for Distributed Functions},
Year = {2004},
Month = {January},
ISBN = {0849312876},
Abstract = {Throughout history, the introduction of new technologies has
significantly impacted human life in many different ways.
Until now, however, each new artificial device or tool
designed to enhance human motor, sensory, or cognitive
capabilities has relied on explicit human motor behaviors
(e.g., hand, finger, or foot movements), often augmented by
automation, in order to translate the subject’s intent
into concrete goals or final products. The increasing use of
computers in our daily lives provides a clear example of
such a trend. Yet, the realization of the full potential of
the “digital revolution” has been hindered by its
reliance on low bandwidth and relatively slow user-machine
interfaces (e.g., keyboard, mouse). Because these
user-machine interfaces are far removed from how the brain
normally interacts with the surrounding environment, the
potential of such a tool is limited by its inherent
inability to be assimilated by the brain’s multiple
internal representations as a continuous extension of our
body appendices or sensory organs.},
Key = {fds340166}
}
@misc{fds340088,
Author = {Matell, MS and Meck, WH and Nicolelis, MAL},
Title = {Integration of behavior and timing: Anatomically separate
systems or distributed processing?},
Pages = {370-392},
Booktitle = {Functional and Neural Mechanisms of Interval
Timing},
Year = {2003},
Month = {January},
ISBN = {9780849311093},
Abstract = {With the recent development of powerful methods to study
brain-behavior relations, the study of interval timing has
rapidly shifted from primarily behavioral analyses
elucidating the psychological constructs of timing to
investigations aimed at identifying the anatomical and
physiological underpinnings of the interval timing system.
This transition to the study of the biological substrates of
interval timing is well timed to stimulate further model
development. Because the various interval timing models are
already extremely accurate at predicting the behavioral data
(Church and Broadbent, 1991; Gibbon, 1977; Killeen and
Fetterman, 1988; Staddon and Higa, 1999), much of their
attractiveness is associated with their philosophical
approach (i.e., behaviorism vs. cognitivism), rather than
their predictive accuracy. Although these models fare quite
well at explaining behavioral data, because of their
fundamental differences, they do not provide us with an
unbiased framework from which to search for the neural
mechanisms of interval timing. As such, we believe that a
theory-free model of interval timing would be valuable. Such
a general timing model is a much needed “place to hang our
hats” when searching for the neural processes associated
with timing and time perception.},
Key = {fds340088}
}
@misc{fds340089,
Author = {Moxon, KA and Morizio, J and Chapin, JK and Nicolelis, MAL and Wolf,
PD},
Title = {Designing a brain- machine interface for neuroprosthetic
control},
Pages = {179-219},
Booktitle = {Neural Prostheses for Restoration of Sensory and Motor
Function},
Year = {2000},
Month = {January},
ISBN = {0849322251},
Abstract = {There are roughly four major subassemblies of a brain
derived neuroprosthetic control device: (1) the electrodes
subassembly, (2) signal conditioning subassembly, (3) signal
acquisition subassembly, and (4) transmitter subassemblies
(Table 6.1). Notably absent from these subassemblies is a
device to generate the command signal. This issue will be
addressed in Chapter 8. Each of these subassemblies has been
studied in detail and some of the major advances are
presented below. However, each of these steps requires major
technological advances in order to produce a device for
clinical use and we will attempt to point out some of the
possible solutions.},
Key = {fds340089}
}
@misc{fds340175,
Author = {Chapin, JK and Nicolelis, MAL},
Title = {Brain control of sensorimotor prostheses},
Pages = {235-261},
Booktitle = {Neural Prostheses for Restoration of Sensory and Motor
Function},
Year = {2000},
Month = {January},
ISBN = {0849322251},
Abstract = {The introduction to this volume outlines the possibilities
inherent in utilizing electronic interfaces with the brain
to alleviate problems of paralysis, such as that caused by
spinal cord injury. The possibility of using
electroencephalographic recordings for this purpose has been
explored, but the amount and specificity of the information
that can be extracted in this way is questionable. As an
alternative, it would theoretically be more efficient, and
more elegant, to utilize control information extracted from
the part of the brain that normally is directly involved in
processing “commands” for voluntary movement of the arm.
In fact, the information contained in the motor areas of the
brain is (by definition) completely sufficient to reproduce
all of the normal movements of the body. It has long been
considered that paralysis victims might benefit from such an
ability to control devices directly from the brain. It would
of course be preferable to utilize non-invasive techniques
for recording the brain activity necessary to control these
devices, but no currently available technique can provide
sufficient information for control of external movement in
real time. Electroencephalography (EEG), for example,
involves recordings from the scalp, and thus can only detect
the common electrical dipoles emerging from billions of
individual neurons in wide areas of the subjacent brain.
Though it has commonly been used for measuring global brain
rhythms, it has not been particularly useful for extracting
brain information specific to a particular limb movement. As
such, when EEG is used as a brain-computer interface, the
subjects must normally learn to control the expression of
these global rhythms. Such approaches have been successfully
utilized for tasks that are not time-critical, such as
selecting letters by using EEG recordings to move a cursor
across a computer screen.},
Key = {fds340175}
}
%% Papers Published
@article{8521262,
Author = {Sung-Phil Kim and Carmena, J.M. and Nicolelis, M.A. and Principe, J.C.},
Title = {Multiresolution representations and data mining of neural
spikes for brain-machine interfaces},
Journal = {2005 2nd International IEEE/EMBS Conference on Neural
Engineering (IEEE Cat. No.05EX938)},
Pages = {221 - 4},
Address = {Arlington, VA, USA},
Year = {2005},
Keywords = {bioelectric phenomena;biomechanics;brain;data
mining;handicapped aids;medical signal detection;neurophysiology;signal
representation;signal resolution;},
Abstract = {In brain-machine interface (BMI) applications, neural firing
activities have been represented by spike counts with a
fixed-width time bin. Adaptive models have been designed to
utilize these bin counts for mapping the associated behavior
which is typically 2D or 3D hand movement. However, the
representation of the firing activities can be enriched by
binning neural spikes with multiple time scales based on
multiresolution analysis. This multiresolution
representation of neural activities can provide more
accurate prediction of the hand movement parameters. Data
mining techniques must be applied to models using
multiresolution representation in order to avoid
over-fitting. In this paper, we demonstrate that the
multiresolution representation improves the performance of
the linear model for BMIs compared to the model with the
fixed-width time bin},
Key = {8521262}
}
@article{8571986,
Author = {Rao, Y.N. and Kim, S.-P. and Sanchez, J.C. and Erdogmus, D. and Principe, J.C. and Carmena, J.M. and Lebedev, M.A. and Nicolelis, M.A.},
Title = {Learning mappings in brain machine interfaces with echo
state networks},
Journal = {2005 IEEE International Conference on Acoustics, Speech, and
Signal Processing (IEEE Cat. No.05CH37625)},
Volume = {Vol. 5},
Pages = {233 - 6},
Address = {Philadelphia, PA, USA},
Year = {2005},
Keywords = {brain models;generalisation (artificial intelligence);learning
(artificial intelligence);multilayer perceptrons;neurophysiology;recurrent
neural nets;},
Abstract = {Brain machine interfaces (BMI) utilize linear or non-linear
models to map the neural activity to the associated behavior
which is typically the 2D or 3D hand position of a primate.
Linear models are plagued by the massive disparity of the
input and output dimensions thereby leading to poor
generalization. A solution would be to use non-linear models
like the recurrent multi-layer perceptron (RMLP) that
provide parsimonious mapping functions with better
generalization. However, this results in a drastic increase
in the training complexity, which can be critical for
practical use of a BMI. This paper bridges the gap between
superior performance per trained weight and model learning
complexity. Towards this end, we propose to use echo state
networks (ESN) to transform the neuronal firing activity
into a higher dimensional space and then derive an optimal
sparse linear mapping in the transformed space to match the
hand position. The sparse mapping is obtained using a weight
constrained cost function whose optimal solution is
determined using a stochastic gradient algorithm},
Key = {8571986}
}
@article{7550839,
Author = {Obeid, I. and Morizio, J.C. and Moxon, K.A. and Nicolelis,
M.A.L. and Wolf, P.D.},
Title = {Two multichannel integrated circuits for neural recording
and signal processing},
Journal = {IEEE Trans. Biomed. Eng. (USA)},
Volume = {50},
Number = {2},
Pages = {255 - 8},
Year = {2003},
url = {http://dx.doi.org/10.1109/TBME.2002.807643},
Keywords = {amplifiers;arrays;biomedical electrodes;biomedical
electronics;CMOS analogue integrated circuits;high-pass
filters;medical signal processing;neurophysiology;prosthetics;somatosensory
phenomena;},
Abstract = {We have developed, manufactured, and tested two analog CMOS
integrated circuit "neurochips" for recording from arrays of
densely packed neural electrodes. Device A is a 16-channel
buffer consisting of parallel noninverting amplifiers with a
gain of 2 V/V. Device B is a 16-channel two-stage analog
signal processor with differential amplification and
high-pass filtering. It features selectable gains of 250 and
500 V/V as well as reference channel selection. The
resulting amplifiers on Device A had a mean gain of 1.99 V/V
with an equivalent input noise of 10 μV<sub>rms</sub>.
Those on Device B had mean gains of 53.4 and 47.4 dB with a
high-pass filter pole at 211 Hz and an equivalent input
noise of 4.4 μV<sub>rms</sub>. Both devices were tested
in vivo with electrode arrays implanted in the somatosensory
cortex},
Key = {7550839}
}
@article{02477219204,
Author = {Nicolelis, Miguel A.L. and Chapin, John K.},
Title = {Controlling Roberts with the mind},
Journal = {Scientific American},
Volume = {287},
Number = {4},
Pages = {46 -},
Year = {2002},
Key = {02477219204}
}
@article{02307034262,
Author = {Hugh, G.S. and Laubach, M. and Nicolelis, M.A.L. and Henriquez, C.S.},
Title = {A simulator for the analysis of neuronal ensemble activity:
Application to reaching tasks},
Journal = {Neurocomputing},
Volume = {44-46},
Pages = {847 - 854},
Year = {2002},
url = {http://dx.doi.org/10.1016/S0925-2312(02)00482-4},
Keywords = {Learning systems;Muscle;Mathematical models;Computer
simulation;},
Abstract = {A biologically based, multi-cortical computational model was
developed to investigate how ensembles of neurons learn to
execute a three-dimensional reaching task. The model
produces outputs of spike trains that can be analyzed using
a variety of multivariate analysis tools. Simulations show
that after learning, the model neurons exhibit broad
directional tuning that depend on the defined muscle
directions of the simulated arm, and that these neurons form
functional clusters within cortical areas. The utility of
the model is demonstrated by testing arm movement prediction
strategies using ensemble activity. © 2002 Published by
Elsevier Science B.V.},
Key = {02307034262}
}
@article{02487243203,
Author = {Nicolelis, Miguel A.L.},
Title = {The amazing adventures of robotrat},
Journal = {Trends in Cognitive Sciences},
Volume = {6},
Number = {11},
Pages = {449 - 450},
Year = {2002},
url = {http://dx.doi.org/10.1016/S1364-6613(02)01991-5},
Keywords = {Brain;Neurophysiology;},
Abstract = {By using electrical brain stimulation to deliver both
'virtual' tactile cues and rewards to freely roaming rats,
Talwar et al. have been able to instruct animals remotely to
navigate through complex mazes and natural environments they
have never visited before. These results provide both an
elegant alternative way to train animals and a new approach
to study basic neurophysiological principles of animal
navigation.},
Key = {02487243203}
}
@article{6897270,
Author = {Krupa, D.J. and Brisben, A.J. and Nicolelis,
M.A.L.},
Title = {A multi-channel whisker stimulator for producing
spatiotemporally complex tactile stimuli},
Journal = {J. Neurosci. Methods (Netherlands)},
Volume = {104},
Number = {2},
Pages = {199 - 208},
Year = {2001},
url = {http://dx.doi.org/10.1016/S0165-0270(00)00345-9},
Keywords = {biological techniques;neurophysiology;touch
(physiological);},
Abstract = {A system is described that delivers complex, biologically
realistic, tactile stimuli to the rat's facial whisker pad
by independently stimulating up to 16 individual facial
whiskers in a flexible yet highly controlled and repeatable
manner. The system is technically simple and inexpensive to
construct. The system consists of an array of 16
miniature-solenoid driven actuators that are attached to 16
individual facial whiskers via very small (130 μm dia.)
Teflon-coated stainless steel wires. When individual
solenoids are energized, the wire is rapidly retracted,
resulting in a deflection of individual whiskers. The rise
time of deflection is approx. 1 mm/ms. Repeatable
stimulation of individual whiskers can be achieved without
touching adjacent whiskers, thereby allowing a very high
density of stimulators to be attached within the spatially
restricted region of the facial whisker pad. Complex
patterns of whisker stimulation (designed to mimic
biologically realistic stimuli) are delivered to the whisker
pad by activating individual solenoid actuators in precisely
controlled temporal patterns. These stimulations can be
combined with multi-electrode single-unit ensemble
recordings at multiple sites within the rat trigeminal
somatosensory system. Analysis of neuronal population
responses to these complex stimuli is intended to examine
how the trigeminal somatosensory system encodes and
processes spatiotemporally complex stimuli},
Key = {6897270}
}
@article{6633289,
Author = {Laubach, W. and Wessberg, J. and Nicolelis,
M.A.L.},
Title = {Cortical ensemble activity increasingly predicts behaviour
outcomes during learning of a motor task},
Journal = {Nature (UK)},
Volume = {405},
Number = {6786},
Pages = {567 - 71},
Year = {2000},
url = {http://dx.doi.org/10.1038/35014604},
Keywords = {bioelectric potentials;biomechanics;brain;neurophysiology;},
Abstract = {When an animal learns to make movements different stimuli,
changes in activity in the motor cortex seem to accompany
and underlie this learning. The precise nature of
modifications in cortical motor areas during the initial
stages of motor learning, however, is largely unknown. Here,
the authors address this issue by chronically recording from
neuronal ensembles located in the rat motor cortex,
throughout the period required for rats to learn a
reaction-time task. Motor learning was demonstrated by a
decrease in the variance of the rats' reaction times and an
increase in the time the animals were able to wait for a
trigger stimulus. These behavioural changes were correlated
with a significant increase in the authors' ability to
predict the correct or incorrect outcome of single trials
based on 3 measures of neuronal ensemble activity: average
firing rate, temporal patterns of firing, and correlated
firing. This increase in prediction indicates that an
association between sensory cues and movement},
Key = {6633289}
}
@article{6540993,
Author = {Laubach, M. and Shuler, M. and Nicolelis,
M.L.},
Title = {Independent component analyses for quantifying neuronal
ensemble interactions},
Journal = {J. Neurosci. Methods (Netherlands)},
Volume = {94},
Number = {1},
Pages = {141 - 54},
Year = {1999},
url = {http://dx.doi.org/10.1016/S0165-0270(99)00131-4},
Keywords = {neurophysiology;principal component analysis;},
Abstract = {The goal of this study was to compare how multivariate
statistical methods for dimension reduction account for
correlations between simultaneously recorded neurons. Here,
the authors describe applications of principal component
analysis (PCA) and independent component analysis (ICA)
(Cardoso, J.-F., Souloumiac, A. IEE-Proc. F 1993; 140:
362-70; Hyvarinen, A., Oja, E. Neural Comput 1997; 9:
1483-92; Lee, T.W., et al. Neural Comp. 1999; 11: 417-41) to
neuronal ensemble data. Simulated ensembles of neurons were
used to compare how well the methods above could account for
correlated neuronal firing. The simulations showed that
`population vectors' defined by PCA were broadly distributed
over the neuronal ensembles; thus, PCA was unable to
identify independent groupings of neurons that shared common
sources of input. By contrast, the ICA methods were all able
to identify groupings of neurons that emerged due to
correlated firing. This result suggests that correlated
neuronal firing is reflected in higher-order correlations
between neurons and not simply in the neurons' covariance.
To assess the significance of these methods for real
neuronal ensembles, the authors analyzed data from
populations of neurons recorded in the motor cortex of rats
trained to perform a reaction-time task. Scores for PCA and
ICA were reconstructed on a bin-by-bin basis for single
trials. These data were then used to train an artificial
neural network to discriminate between single trials with
either short or long reaction-times. Classifications based
on scores from the ICA-based methods were significantly
better than those based on PCA. For example, scores for
components defined with an ICA-based method, extended ICA
(Lee et al., 1999), classified more trials correctly
(80.58±1.25%) than PCA (73.14±0.84%) for an
ensemble of 26 neurons recorded in the motor cortex (ANOVA:
P<0.005). This result suggests that behaviorally relevant
information is represented in correlated neuronal firing and
can be best detected when higher-order correlations between
neurons are taken into account},
Key = {6540993}
}
@article{6533555,
Author = {Chapin, J.K. and Nicolelis, M.A.L.},
Title = {Principal component analysis of neuronal ensemble activity
reveals multidimensional somatosensory representations},
Journal = {J. Neurosci. Methods (Netherlands)},
Volume = {94},
Number = {1},
Pages = {121 - 40},
Year = {1999},
url = {http://dx.doi.org/10.1016/S0165-0270(99)00130-2},
Keywords = {cellular biophysics;neural nets;neurophysiology;principal
component analysis;somatosensory phenomena;},
Abstract = {Principal components analysis (PCA) was used to define the
linearly dependent factors underlying sensory information
processing in the vibrissal sensory area of the ventral
posterior medial (VPM) thalamus in 8 awake rats. Ensembles
of up to 23 single neurons were simultaneously recorded in
this area, either during long periods of spontaneous
behavior (including exploratory whisking) or controlled
deflection of single whiskers. PCA rotated the matrices of
correlation between these n neurons into a series of n
uncorrelated principal components (PCs), each successive PC
oriented to explain a maximum of the remaining variance. The
fact that this transformation is mathematically equivalent
to the general Hebb algorithm in linear neural networks
provided a major rationale for performing it here on data
from real neuronal ensembles. Typically, most information
correlated across neurons in the ensemble was concentrated
within the first 3-8 PCs. Each of these was found to encode
distinct, and highly significant informational factors.
These factor encodings were assessed in two ways, each
making use of fact that each PC consisted of a matrix of
weightings, one for each neuron. First, the neurons were
rank ordered according to the locations of the central
whiskers in their receptive fields, allowing their
weightings within different PCs to be viewed as a function
of their position within the whisker representation in the
VPM. Each PC was found to define a distinctly different
topographic mapping of the cutaneous surface. Next, the PCs
were used to weight-sum the neurons' simultaneous activities
to create population vectors (PVs). Each PV consisted of a
single continuous time series which represented the
expression of each PC's `magnitude' in response to
stimulation of different whiskers, or during behavioral
events such as active tactile whisking. These showed that
each PC functioned as a feature detector capable of
selectively predicting significant sensory or behavioral
events with far greater statistical reliability than could
any single neuron. The encoding characteristics of the first
few PCs were remarkably consistent across all animals and
experimental conditions, including both spontaneous
exploration and direct sensory stimulation: PC1 positively
weighted all neurons, mainly according to their covariance,
Thus it encoded global magnitude of ensemble activity,
caused either by combined sensory inputs or intrinsic
network activity, such as spontaneous oscillations. PC2
encoded spatial position contrast, generally in the
rostrocaudal dimension, across the whole cutaneous surface
represented by the ensemble. PC3 more selectively encoded
contrast in an orthogonal (usually dorsoventral) dimension.
A variable number of higher numbered PCs encoded local
position contrast within one or more smaller regions of the
cutaneous surface. The remaining PCs typically explained
residual `noise', i.e. the uncorrelated variance that
constituted a major part of each neuron's activity.
Differences in behavioral or sensory experience produced
relatively little in the PC weighting patterns but often
changed the variance they explained (eigenvalues) enough to
alter their ordering. These results argue that PCA provides
a powerful set of tools for selectively measuring neural
ensemble activity within multiple functionally significant
`dimensions' of information processing. As such, it
redefines the `neuron' as an entity which contributes
portions of its variance to processing not one, but several
tasks},
Key = {6533555}
}
@article{97103891001,
Author = {Faggin, B. M. and Nguyen, K. T. and Nicolelis, M. A.
L.},
Title = {Immediate and simultaneous sensory reorganization at
cortical and subcortical levels of the somatosensory
system},
Journal = {Proceedings of the National Academy of Sciences of the
United States of America},
Volume = {94},
Number = {17},
Pages = {9428 -},
Year = {1997},
url = {http://dx.doi.org/10.1073/pnas.94.17.9428},
Key = {97103891001}
}
@article{4984702,
Author = {Nicolelis, M.A.L. and Baccala, L.A. and Lin, R.C.S. and Chapin, J.K.},
Title = {Sensorimotor encoding by synchronous neural ensemble
activity at multiple levels of the somatosensory
system},
Journal = {Science (USA)},
Volume = {268},
Number = {5215},
Pages = {1353 - 8},
Year = {1995},
Keywords = {brain;mechanoception;neurophysiology;},
Abstract = {Neural ensemble processing of sensorimotor information
during behavior was investigated by simultaneously recording
up to 48 single neurons at multiple relays of the rat
trigeminal somatosensory system. Cortical, thalamic, and
brainstem neurons exhibited widespread 7- to 10-hertz
synchronous oscillations, which began during attentive
immobility and reliably predicted the imminent onset of
rhythmic whisker twitching. Each oscillatory cycle began as
a traveling wave of neural activity in the cortex that then
spread to the thalamus. Just before the onset of rhythmic
whisker twitching, the oscillations spread to the spinal
trigeminal brainstem complex. Thereafter, the oscillations
at all levels were synchronous with whisker protraction.
Neural structures manifesting these rhythms also exhibited
distributed spatiotemporal patterns of neuronal ensemble
activity in response to tactile stimulation. Thus,
multilevel synchronous activity in this system may encode
not only sensory information but also the onset and temporal
domain of tactile exploratory movements},
Key = {4984702}
}
@article{93051588763,
Author = {Nicolelis, M.A.L. and Lin, R.C.S. and Woodward, D.J. and Chapin, J.K.},
Title = {Induction of immediate spatiotemporal changes in thalamic
networks by peripheral block of ascending cutaneous
information},
Journal = {Nature},
Volume = {361},
Number = {6412},
Pages = {533 -},
Year = {1993},
url = {http://dx.doi.org/10.1038/361533a0},
Key = {93051588763}
}
@article{3878412,
Author = {Baccala, L.A. and Nicolelis, M.A.L. and Chai-Hong Yu and Oshiro, M.},
Title = {Structural analysis of neural circuits using the theory of
directed graphs},
Journal = {Comput. Biomed. Res. (USA)},
Volume = {24},
Number = {1},
Pages = {7 - 28},
Year = {1991},
url = {http://dx.doi.org/10.1016/0010-4809(91)90010-T},
Keywords = {directed graphs;neural nets;},
Abstract = {A new approach to analysis of structural properties of
biological neural circuits is proposed based on their
representation in the form of abstract structures called
directed graphs. To exemplify this methodology, structural
properties of a biological neural network and randomly wired
circuits (RC) were compared. The analyzed biological circuit
(BC) represented a sample of 39 neural nuclei which are
responsible for the control of the cardiovascular function
in higher vertebrates. Initially, direct connections of both
circuits were stored in a square matrix format. Then,
standard algorithms derived from the theory of directed
graphs were applied to analyze the pathways of the circuits
according to their length (in number of synapses), degree of
connectedness, and structural strength. Thus, the BC was
characterized by the presence of short, reciprocal, and
unidirectional pathways which presented a high degree of
heterogeneity in their strengths. This heterogeneity was
mainly due to the existence of a small cluster of
reciprocally connected neural nuclei in the circuit that
have access, through short pathways, to most of the
network},
Key = {3878412}
}
@article{3835485,
Author = {Nicolelis, M.A.L. and Chia-Hong Yu and Baccala,
L.A.},
Title = {Structural characterization of the neural circuit
responsible for control of cardiovascular functions in
higher vertebrates},
Journal = {Comput. Biol. Med. (UK)},
Volume = {20},
Number = {6},
Pages = {379 - 400},
Year = {1990},
url = {http://dx.doi.org/10.1016/0010-4825(90)90019-L},
Keywords = {cardiology;neural nets;neurophysiology;zoology;},
Abstract = {A comparison of structural properties of a biological neural
system responsible for cardiovascular function control in
higher vertebrates with randomly connected networks was
pursued using matrix representations of those circuits. The
biological circuit was characterized by the presence of some
heavily connected nuclei in contrast to the random networks
that had equally distributed connections between their
elements. This property of the analysed biological circuit
was shown to account for a high logarithmic correlation
found between two indexes defined to represent pointwise
features of the nuclei and their global contribution to the
whole network. The first index is obtained by the product of
the number of inputs and of outputs of a nucleus and was
called the power index (PI). The second one, called the
occurrence index (OI), defines how many times a specific
nucleus is crossed when all possible pathways joining two
nuclei of the circuit are obtained. This PI-OI correlation
was clearly dependent on the pathway length distribution
(expressed in number of synapses), and was maximal
considering pathways with a low number of synapses. When
randomly connected circuits were analysed, lower correlation
was found between the same two indexes and only for much
longer pathways. Therefore, it is proposed that the analysis
of the PI-OI correlation can be useful to quantify
structural differences between biological neural circuits as
distinguished from randomly connected networks and also
between neural systems at different levels of phylogenetic
and ontogenetic development},
Key = {3835485}
}
@article{3616675,
Author = {Nicolelis, M.A.L. and Tinone, G. and Sameshima, K. and Timo-Iaria, C. and Yu Chia Hong and Van de Bilt,
M.T.},
Title = {Connection, a microcomputer program for storing and
analyzing structural properties of neural
circuits},
Journal = {Comput. Biomed. Res. (USA)},
Volume = {23},
Number = {1},
Pages = {64 - 81},
Year = {1990},
url = {http://dx.doi.org/10.1016/0010-4809(90)90007-Y},
Keywords = {biology computing;medical diagnostic computing;microcomputer
applications;neurophysiology;},
Abstract = {The application of a microcomputer-based system (the
Connection system) designed to deal with neuroanatomical
information commonly analyzed by researchers and involved in
the study of structural properties of neural circuits is
presented. This system can be employed at first as a
readily-accessible database containing physiological and
anatomical data from nuclei of the central nervous system
which define a network with up to 45 elements and their
subdivisions and connections. Once the database from a
specific network is built and stored in a file, routines of
this system can be used to classify the nuclei in terms of
their afferents and efferents and also to display all
possible pathways linking any pair of nuclei and their
respective length (number of synapses). The role of such a
system as an auxiliary tool in neuroanatomical and
electrophysiological research is discussed by presenting the
results obtained from the analysis of the neural circuits
involved in cardiovascular function control in higher
vertebrates},
Key = {3616675}
}
@article{3706431,
Author = {Yu Chia-Hong and Baccala, L.A. and Nicolelis,
M.A.},
Title = {Applying graph theory on a neural network responsible for
the cardiovascular function control: a correlation between
structural properties and physiological functions},
Journal = {MEDINFO 89. Proceedings of the Sixth Conference on Medical
Informatics},
Pages = {87 - 91},
Address = {Beijing, China and Singapore},
Year = {1989},
Keywords = {cardiology;graph theory;neural nets;neurophysiology;},
Abstract = {A neural network responsible for the cardiovascular function
control in high vertebrates represented by 40 neural nuclei
and 162 direct connections between them, was analyzed by
means of graph theory procedures. This quantitative
structural analysis proved useful in forecasting the
physiological role of each nucleus in the overall control
process. New graph procedures were introduced, combining
both pointwise and distributed features of the network and
were successful in highlighting a set of neural nodes that
play a crucial physiological role in maintaining blood
pressure, heart rate and vasomotor tone},
Key = {3706431}
}
@article{3327494,
Author = {Lage, S.G. and Gutierrez, M.A. and Nicolelis, M.A.L. and Furuie, S.S.},
Title = {A bedside computerized system for monitoring and processing
of biological signals in intensive care units},
Journal = {Computers in Cardiology (Cat. No.87CH2544-5)},
Pages = {561 - 4},
Address = {Leuven, Belgium},
Year = {1988},
Keywords = {computerised monitoring;computerised signal
processing;medical computing;patient care;patient
monitoring;},
Abstract = {A description is given of the application of a generic
bedside system, developed using an IBM-PC compatible, with
the aim of getting essential biological signals to perform a
complete cardiovascular function analysis. Six cardiac
patients with critical heart failure impaired by arrhythmia,
infection, pulmonary embolism and myocardial infarction were
monitored through: (a) ECG; (b) VCG; (c) hemodynamic data
(right atrial pressure, pulmonary arterial pressure,
pulmonary wedge pressure, systemic pressure); (d) cardiac
output (thermodilution and thoracic electrical
bioimpedance); (e) <i>dZ</i>/<i>dt</i> of TEB. These signals
were stored and processed to furnish the
electrical-hemodynamic coupling correlation. As a control,
the results of the cardiac output calculated by TEB were
compared to the thermodilution method. The
<i>dZ</i>/<i>dt</i> wave together with the ECG and
hemodynamic signals allowed continuous determination of the
pre-ejection period, ventricular ejection time,
isovolumetric relaxation, time and ventricular filling
period. The system also permitted several devices to be
interfaced to the microcomputer, a better therapeutic
approach for critical patients, as well as providing data
for medical education and research},
Key = {3327494}
}
@article{3305485,
Author = {Gutierrez, M.A. and Furuie, S.S. and Nicolelis, M.A.L. and Lage, S.},
Title = {Developing a multi-purpose microcomputer-based system for
biological signal analysis for cardiovascular
protocols},
Journal = {Computers in Cardiology (Cat. No.87CH2544-5)},
Pages = {505 - 8},
Address = {Leuven, Belgium},
Year = {1988},
Keywords = {cardiology;computerised signal processing;medical diagnostic
computing;microcomputer applications;},
Abstract = {A description is given of the development of a general
microcomputer-based system to perform biological signal
processing concerning clinical and experimental protocols in
cardiology. In intensive care units the software of this
system enabled the clinical staff to acquire several signals
simultaneously (such as cardiac chamber pressures, arterial
pressure, respiratory flow, ECG, and EEG) and to interface
an IBM PC compatible with other devices (for example a
thoracic electrical bioimpedance system) which can furnish
important ventricular stroke volume measurements. On the
other hand, in experimental protocols, where the
relationship between the latter signals with action
potentials from peripheral nerves was investigated, it was
necessary to design a window discriminator (WD) that allowed
the study of point processes related to the neural control
of the cardiovascular system. This WD was connected to the
microcomputer through a parallel interface with minor
modifications. The software was divided into modules. To
evaluate the signals after acquisition several basic
routines are available (smoothing, statistical and spectral
procedures)},
Key = {3305485}
}
@article{3222798,
Author = {Nicolelis, M.A.L. and Yu Chia Hong},
Title = {Applications of a microcomputer-based system in the analysis
of infection data at the emergency units of a large
hospital},
Journal = {Int. J. Bio-Med. Comput. (Netherlands)},
Volume = {22},
Number = {3-4},
Pages = {183 - 98},
Year = {1988},
Keywords = {data analysis;medical administrative data processing;medical
computing;microcomputer applications;surgery;},
Abstract = {After three years of retrospective study in four emergency
units from a large hospital and analysis of 6283 positive
cultures, a microcomputer database system was built to store
information concerning nosocomial infections in order to
help the clinical staff from those units to study the
incidence of 20 bacterial species and their sensitivity
pattern evolutions for 27 antibiotics. This system was
developed as an alternative to the hospital mainframe
computer microbiological reports. It put emphasis on
graphical outputs instead of the coded tables generated by
the bigger system. This orientation and the possibility of
sectorial infection data analysis were responsible for the
general acceptance of the microcomputer-based system by the
clinical staff. As the first practical results, the system
was able to detect a particular increase in the incidence of
Staphylococcus aureus in surgical emergency units as well as
the dissemination of the antimicrobial resistance patterns
of S. aureus and Klebsiella pneumoniae from the surgical
units to the clinical ones. The time evolution behaviour of
Pseudomonas aeruginosa, Escherichia coli and other
nonfermentative Gram negative bacilli was also studied to
complete the analysis of the most pathogenic bacterial
species found in the emergency units},
Key = {3222798}
}
@article{3361609,
Author = {Nicolelis, M.A.L. and Sameshima, K. and Furuie, S.S. and Gutierrez, M.A.},
Title = {Signal processing system to analyze the neural control on
the cardiovascular function},
Journal = {EFMI - European Federation for Medical Informatics Medical
Informatics Europe '87. Proceedings of the Seventh
International Congress},
Pages = {1318 - 22},
Address = {Rome, Italy},
Year = {1987},
Keywords = {biocontrol;cardiology;computerised signal
processing;microcomputer applications;neurophysiology;},
Abstract = {The study of the neural control on the cardiovascular
function involves the analysis of multiple servomechanisms
with different integration levels in the central nervous
system (1). The input branches of these servomechanisms are
represented by several types of sensors distributed around
the cardiovascular system. To observe the patterns of the
sensor activity together with the signals provided by the
result of the servomechanism effector branch action
(hemodynamic and ECG traces) it was necessary to develop a
system which could sample signals in a broad spectral range.
Describes a microcomputer based system to perform this task,
enabling the user to acquire and analyze on the whole the
signals that are related to the cardiovascular control
process. The hardware (PC/XT and LYNX ADC) and software are
briefly described along with experimental
results},
Key = {3361609}
}
@article{2959216,
Author = {Massad, E. and Engel, A.B. and Nicolelis,
M.A.L.},
Title = {A mathematical model for spirometry},
Journal = {Comput. Biomed. Res. (USA)},
Volume = {20},
Number = {2},
Pages = {105 - 12},
Year = {1987},
url = {http://dx.doi.org/10.1016/0010-4809(87)90038-3},
Keywords = {medical computing;microcomputer applications;physiological
models;pneumodynamics;},
Abstract = {A model originally designed to fit population growth data
was investigated to determine whether it could fit
spirometric traces as a function of time in normal and ill
humans and in normal rats, obtained, respectively, by
spirometer and whole-body plethysmography. The model showed
great accuracy when applied to a simple spirometer coupled
with an analog-to-digital converter interfaced with a
personal computer. It also proved to be a good alternative
for the more expensive and less accurate electronic devices,
as derivative systems, and may be an attractive method for
research and/or diagnostic centers},
Key = {2959216}
}
@article{2602199,
Author = {Massad, E. and Furuie, S.S. and de Assis Moura and L., Jr. and Nascimento Saldiva and P.H. and Nicolelis, M.A. and Bohm,
G.M.},
Title = {The use of a personal computer in the pulmonary function
tests of laboratory rats},
Journal = {Methods Inf. Med. (West Germany)},
Volume = {24},
Number = {4},
Pages = {197 - 9},
Year = {1985},
Keywords = {analogue-digital conversion;Apple computers;biology
computing;microcomputer applications;pneumodynamics;},
Abstract = {A system consisting of an 8-bit word microcomputer of the
APPLE line equipped with an analog-to-digital converter,
connected to a physiograph measuring pressures from a whole
body plethysmograph, was used to perform pulmonary tests in
rats. The system proved to be time-saving without loss of
accuracy when compared to manual calculation methods. It
allows measurement repetition during the same experiment,
which is impossible by manual techniques, and permits to
obtain flow/volume relationships without pneumotachographs
or integrator and/or differentiator modules. This approach
may be applied to humans and used by any
physician},
Key = {2602199}
}
@article{7951637,
Author = {Wiest, M.C. and Nicolelis, M.A.L.},
Title = {Behavioral detection of tactile stimuli during 7-12 Hz
cortical oscillations in awake rats},
Journal = {Nat. Neurosci. (USA)},
Volume = {6},
Number = {9},
Pages = {913 - 14},
url = {http://dx.doi.org/10.1038/nn1107},
Keywords = {bioelectric potentials;biological techniques;brain;microelectrodes;neurophysiology;touch
(physiological);},
Abstract = {Prominent 7-12 Hz oscillations in the primary somatosensory
cortex (S1) of awake but immobile rats might represent a
seizure-like state1 in which neuronal burst firing renders
animals unresponsive to incoming tactile stimuli; others
have proposed that these oscillations are analogous to human
μ rhythm. To test whether rats can respond to tactile
stimuli during 7-12 Hz oscillatory activity, we trained
head-immobilized awake animals to indicate whether they
could detect the occurrence of transient whisker deflections
while we recorded local field potentials (LFPs) from
microelectrode arrays implanted bilaterally in the S1
whisker representation area. They responded rapidly and
reliably, suggesting that this brain rhythm represents
normal physiological activity that does not preclude
perception},
Key = {7951637}
}
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