Effects of Stimulus Waveform on Magnetic Nerve Stimulation

Abstract

The dependence of nerve excitability on the waveform of a magnetic stimulus was experimentally and analytically studied. In the experiment frog sciatic nerves were stimulated by pulsed magnetic fields which had damped sinusoidal waveforms with different numbers of cycles. In the analysis a neuroelectric model of the myelinated nerve fiber was assumed to be stimulated by pulsed magnetic fields with various waveforms which were produced in an LCR series circuit. Both the experiment and the analysis show that the excitation threshold of the nerve depends strongly on the number of oscillating cycles. The magnetic stimulus with one-cycle oscillation is useful to excite the nerve in practice.