A QUANTITATIVE APPROACH TO MODELING MAMMALIAN MYELINATED NERVE-FIBERSFOR ELECTRICAL PROSTHESIS DESIGN

This paper presents an upgraded cable model of mammalian myelinated ne rve fibers in an extracellularly applied field. The kinetics of the no des is based upon voltage clamp data in rat motor fibers at 37 degrees C [18], while the resting membrane potential is computed with the Gol dman equation. The resulting spike shape, conduction velocity, strengt h/duration behavior, and absolute and relative refractory period are i n good quantitative agreement with published experimental data in mamm als at normal body temperature and at 20 degrees C. Results at interme diate temperatures however. suggest that the widely used concept of a constant Q(10) for the rate constants is invalid. In addition, the mod el generates realistic abortive spikes towards the end of the absolute refractory period and it can describe the consequences of repetitive firing. The results stress the advantages of a multiple nonlinear node model even if only time aspects of nerve behavior are under study. It turned out, that the model presented here describes in vivo neural pr operties relevant for electrical prosthesis design better than previou s models in literature.