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David Fitzpatrick, James B. Duke Professor Emeritus of Medicine

 

David Fitzpatrick

Research in the Fitzpatrick lab is focused on understanding the functional organization and development of circuits in primary visual cortex, an important component of the vast network of neural centers that are involved in processing visual information and the first site along the visual pathway where neurons exhibit selectivity for stimulus attributes such as the orientation of edges and the direction of motion of objects. Our research combines optical imaging, intracellular recording and neural tracing techniques to explore how stimulus features are represented in the activity of identified neural circuits. Our work on the development of visual cortex suggests that normal sensory experience is required to complete the maturation of properties that are first established by experience-independent mechanisms. In another series of experiments we are addressing how feedforward and recurrent circuits contribute to the orientation selective responses of individual neurons. Our results indicate a remarkable specificity in the spatial arrangement of the axonal arbors associated with these two systems, a specificity that imparts an axial bias to the way these neurons sample information from visual space both within and beyond their classical receptive field. In another set of experiments, we are exploring how different combinations of stimulus features such as orientation, direction of motion and speed are represented in the population response of visual cortical neurons. Contrary to the conventional view that activity patterns in visual cortex can be explained as the intersection between multiple stimulus feature maps, our results indicate that population activity is best explained as a single spatiotemporal transform in which orientation, direction of motion and speed are combined. Current efforts are directed at understanding the temporal dynamics of this spatiotemporal transform and the way in which it is altered by changes in luminance and contrast.

Contact Info:
Office Location:  427C Bryan Res Bldg, Durham, NC 27710
Office Phone:  (919) 684-5385
Email Address: send me a message
Web Page:  http://faculty.duhs.duke.edu/faculty/info?pid=573

Education:

Ph.D.Duke University1982

Research Interests:

Research in the Fitzpatrick lab is focused on understanding the functional organization and development of circuits in primary visual cortex, an important component of the vast network of neural centers that are involved in processing visual information and the first site along the visual pathway where neurons exhibit selectivity for stimulus attributes such as the orientation of edges and the direction of motion of objects. Our research combines optical imaging, intracellular recording and neural tracing techniques to explore how stimulus features are represented in the activity of identified neural circuits. Our work on the development of visual cortex suggests that normal sensory experience is required to complete the maturation of properties that are first established by experience-independent mechanisms. In another series of experiments we are addressing how feedforward and recurrent circuits contribute to the orientation selective responses of individual neurons.  Our results indicate a remarkable specificity in the spatial arrangement of the axonal arbors associated with these two systems, a specificity that imparts an axial bias to the way these neurons sample information from visual space both within and beyond their classical receptive field.  In another set of experiments, we are exploring how different combinations of stimulus features such as orientation, direction of motion and speed are represented in the population response of visual cortical neurons.  Contrary to the conventional view that activity patterns in visual cortex can be explained as the intersection between multiple stimulus feature maps, our results indicate that population activity is best explained as a single spatiotemporal transform in which orientation, direction of motion and speed are combined.  Current efforts are directed at understanding the temporal dynamics of this spatiotemporal transform and the way in which it is altered by changes in luminance and contrast.

Keywords:

Action Potentials • Afferent Pathways • Animals • Autoradiography • Axonal Transport • Axons • Biological Transport • Biological Transport, Active • Brain • Brain Mapping • Carboxy-Lyases • Catecholamines • Cats • Cell Count • Cell Line • Cerebral Cortex • Colchicine • Coloring Agents • Contrast Sensitivity • Corpus Callosum • Dendrites • Diagnostic Imaging • Dominance, Cerebral • Drug Evaluation, Preclinical • Efferent Pathways • Electric Stimulation • Electrodes • Electron Transport Complex IV • Evoked Potentials • Evoked Potentials, Visual • Eyelids • Female • Ferrets • Form Perception • Functional Laterality • Galago • gamma-Aminobutyric Acid • Geniculate Bodies • Glutamate Decarboxylase • Haplorhini • Hippocampus • Histological Techniques • Horseradish Peroxidase • Image Processing, Computer-Assisted • Immunochemistry • Immunoenzyme Techniques • Immunohistochemistry • Immunologic Techniques • Learning • Lectins • Macaca • Macaca fascicularis • Macaca nemestrina • Male • Medulla Oblongata • Microinjections • Microscopy, Electron • Microspheres • Motion Perception • Nerve Endings • Nerve Fibers • Nerve Net • Neural Pathways • Neurons • Ocular Physiological Phenomena • Ocular Physiology • Opossums • Optics and Photonics • Orientation • Patch-Clamp Techniques • Phosphopyruvate Hydratase • Photic Stimulation • Radioligand Assay • Rats • Retina • Retinal Ganglion Cells • Saimiri • Sensation • Somatostatin • Space Perception • Species Specificity • Synapses • Synaptic Transmission • Thalamic Nuclei • Thalamus • Time Factors • Tupaiidae • Video Recording • Vision • Vision, Binocular • Vision, Monocular • Visual Cortex • Visual Fields • Visual Pathways • Visual Perception • Wheat Germ Agglutinins

Representative Publications   (More Publications)

  1. Mooser, F; Bosking, WH; Fitzpatrick, D, A morphological basis for orientation tuning in primary visual cortex., Nature Neuroscience, vol. 7 no. 8 (August, 2004), pp. 872-879, ISSN 1097-6256 [15258585], [doi]  [abs]
  2. Basole, A; White, LE; Fitzpatrick, D, Mapping multiple features in the population response of visual cortex., Nature, vol. 423 no. 6943 (June, 2003), pp. 986-990, ISSN 1476-4687 [12827202], [doi]  [abs]
  3. Chisum, HJ; Mooser, F; Fitzpatrick, D, Emergent properties of layer 2/3 neurons reflect the collinear arrangement of horizontal connections in tree shrew visual cortex., The Journal of neuroscience : the official journal of the Society for Neuroscience, vol. 23 no. 7 (April, 2003), pp. 2947-2960, ISSN 1529-2401 [12684482]  [abs]
  4. Bosking, WH; Crowley, JC; Fitzpatrick, D, Spatial coding of position and orientation in primary visual cortex., Nature Neuroscience, vol. 5 no. 9 (September, 2002), pp. 874-882, ISSN 1097-6256 [12195429], [doi]  [abs]
  5. White, LE; Coppola, DM; Fitzpatrick, D, The contribution of sensory experience to the maturation of orientation selectivity in ferret visual cortex., Nature, vol. 411 no. 6841 (June, 2001), pp. 1049-1052, ISSN 0028-0836 [11429605], [doi]  [abs]
  6. Bosking, WH; Zhang, Y; Schofield, B; Fitzpatrick, D, Orientation selectivity and the arrangement of horizontal connections in tree shrew striate cortex., The Journal of neuroscience : the official journal of the Society for Neuroscience, vol. 17 no. 6 (March, 1997), pp. 2112-2127, ISSN 0270-6474 [9045738]  [abs]
  7. Weliky, M; Bosking, WH; Fitzpatrick, D, A systematic map of direction preference in primary visual cortex., Nature, vol. 379 no. 6567 (February, 1996), pp. 725-728, ISSN 0028-0836 [8602218], [doi]  [abs]