Figure 7
From: A compact theory of magnetic nerve stimulation: predicting how to aim
Simplified model of a non-myelinated axon in a longitudinal voltage gradient E L , directed along the axon. Voltage sensitive ion channels (not shown) are closed during subthreshold stimulation. If “batteries” ELΔL appear at time zero, then currents will flow in loops shown to charge capacitors with the short time constant RaC. For n segments a steady state voltage n ⋅ ELΔL = EL ⋅ L will appear between ends separated by Rtot = nRa and with EL ⋅ L/2 across each capacitance, C.