A new method to predict neural excitation thresholds for applied electric fields

We have developed a method to predict excitation thresholds of axons based on the response of passive cable models. An expression describing the transmembrane potential Induced in passive cables by an applied electric field is presented. Two terms were found to drive the polarization of a node: a source term described by the activating function at the node, and an ohmic term resulting from redistribution of current from sources at other nodes. The expression is used to predict accurately threshold currents, and greatly reduces the computation time necessary to determine the current required to excite a large number of fibers.