Selective stimulation of smaller nerve fibers using biphasic rectangular pulses.

Based on the F-H model, a simulation system to study the excitation properties of myelinated nerve fibers was developed. In order to minimize electrochemical damage of nerve tissue, three selective stimulation methods employing biphasic rectangular pulses were studied, which use single, double and triple electrodes, respectively. The simulation results prove that all of the three methods are effective in selective stimulation of smaller nerve fibers in a compound nerve trunk under certain conditions. The feasibility of these methods is also verified by animal experiments on the sciatic nerve trunks of toads. The amplitude and delay of compound action potential and the results of collision experiments proved that the methods are valid. These methods will be very useful in functional neuromuscular stimulation.