Modeling the excitation of fibers under surface electrodes

It was demonstrated previously by the author (see J. Theor. Biol., vol.125, p.339-49, 1987) that the electrostimulation of nerve or muscle fibers is caused by the activating function, which is the second differential quotient of the extracellular potential along with fiber. To find the activating function, a simple model is used to approximate the potential distribution produced by a surface electrode in a homogeneous medium. Data from classical space-clamped experiments allow calculation of fiber response as a function of geometry and stimulating signal shape.