Papers Published

1. Richardson, A.G. and McIntyre, C.C. and Grill, W.M., Modelling the effects of electric fields on nerve fibres: influence of the myelin sheath, Med. Biol. Eng. Comput. (UK), vol. 38 no. 4 (2000), pp. 438 - 46 .
   (last updated on 2007/04/13)

   Abstract:
   The excitation and conduction properties of computer-based cable models of mammalian motor nerve fibres, incorporating 3 different myelin representations, are compared. The 3 myelin representations are a perfectly insulating single cable (model A), a finite impedance single cable (model B) and a finite impedance double cable (model C). Extracellular stimulation of the 3 models is used to study their strength-duration and current-distance (I-X) relationships, conduction velocity (CV) and action potential shape. All 3 models have a chronaxie time that is within the experimental range. Models B and C have increased threshold currents compared with model A, but each model has a slope to the I-X relationship that matches experimental results. Model B has a CV that matches experimental data, whereas the CV of models A and C are above and below the experimental range, respectively. Model C is able to produce a depolarising afterpotential (DAP), whereas models A and B exhibit hyperpolarising afterpotentials. Models A and B are determined to be the preferred models when low-frequency stimulation (<~25 Hz) is used, owing to their efficiency and accurate excitation and conduction properties. For high frequency stimulation (~25 Hz and greater), model C, with its ability to produce a DAP, is necessary accurately to simulate excitation behaviour

   Keywords:
   bioelectric phenomena;biological effects of fields;cellular effects of radiation;digital simulation;electric field effects;neurophysiology;physiological models;