High frequency mammalian nerve conduction block: simulations and experiments

Abstract

High frequency alternating current (HFAC) sinusoidal waveforms can block conduction in mammalian peripheral nerves. A nerve simulation software package was used to simulate HFAC conduction block in a mammalian axon model. Eight axon diameters from 7.3 microm to 16 microm were tested using sinusoidal waveforms between 1 kHz to 40 kHz. Block was obtained between 3 kHz to 40 kHz and the current threshold for block increased linearly with frequency above 10 kHz. Conduction block was also obtained for all axon diameters, and the block threshold varied inversely with diameter. Upon initiation, the HFAC waveform produced one or more action potentials. These simulation results closely parallel previous experimental results of high frequency motor block of the rat sciatic nerve. During steady state HFAC block, the axons showed a depolarization of multiple nodes, suggesting a possible depolarization mechanism for HFAC conduction block.