title: Electric field stimulation of excitable tissue.
abstract: This paper examines the transmembrane voltage response of an unmyelinated fiber to a stimulating electric field from a point current source. For subthreshold conditions, analytic expressions for the transmembrane potential, vm, are developed that include the specific effects of fiber-source distance, h, and time from the onset of the stimulus, T. Suprathreshold effects are determined for two examples by extending the analytical results with a numerical model. The vm response is a complex evolution in time, especially for small h, that differs markedly from the "activating function." In general, the subthreshold response is a good predictor of the wave shape of the suprathreshold vm, but a poor predictor of its magnitude. The subthreshold response also is a good (but not a precise) predictor of the region where excitation begins.
authors.affiliation: Department of Biomedical Engineering, Duke University, Durham, NC 27708-0281, USA.
authors.forename: R
authors.initials: R
authors.lastname: Plonsey
authors.forename: R C
authors.initials: RC
authors.lastname: Barr
mesh_terms: D000818:Animals; D004056:Differential Threshold; D004553:Electric Conductivity; D004558:Electric Stimulation; D006801:Humans; D008564:Membrane Potentials; D008959:Models, Neurological; D009412:Nerve Fibers / Q000502:physiology*; D011237:Predictive Value of Tests; D013997:Time Factors