P R Health Sci J
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The steady-state cable equations were used to describe the response of discontinuous neuronal cylinders to extracellular electric fields. Where two unequal diameters join, there forms a strong local peak of membrane polarization. ⋯ In contrast, altering the specific membrane resistance along part of a uniformly shaped axon affects the general level of membrane potential without causing a local peak. Field-effects due to structural discontinuities, although relevant to the interpretation of experiments using electrical stimulation, are shown to be of minor functional consequence compared to chemical gating of membrane current.