Improved cable function to represent the excitation of peripheral nerves

The classical cable function has been used to represent the response of peripheral nerves stimulated by an external parallel electric field. This function cannot describe the excitation of peripheral nerves stimulated by a perpendicular electric field. In the present paper, responses of the Ranvier nodes to a transverse-field are thoroughly investigated by mathematic simulation. This simulation demonstrates that the excitation results from the net inward current driven by an external field. Based on a two-stage process, a novel model is introduced to describe peripheral nerves stimulated by a transverse-field, and the classical cable function is modified. Using this modified cable equation, the excitation threshold of peripheral nerves in a transverse field during MS is obtained. The modified cable equation can be used to represent the response of peripheral nerves by an arbitrary electric field.