Electrical conductivity in cat cerebellar cortex

Abstract

Electrical conductivity in molecular and granular layers of cat cerebellar cortex is studied, taking into account anisotropy. A suitable mathematical analysis involving a Green's function approach gives an equation relating voltage to three principal variables: the magnitude of the point current source, the distance from the source, and the conductivities in each of three orthogonal directions. Voltage is measured experimentally as a function of distance in the molecular and granular layers of the cerebellum. The results of these measurements are used to provide an empiric fit to the derived equations. From a set of parameters obtained from the fitted curves, the electrical conductivities are calculated. Sample values of the conductivities are used for three dimensional plots of voltage as a function of two space coordinates, to show the degree of anisotropy in two of the three directions. Results indicate that the conductivities for each direction in the granular layer are all of the order of 2.0 mmho/cm. In the molecular layer, the conductivity in two directions is about 3.0 mmho/cm, but in the other direction it is 1.7 mmho/cm. The granular layer is more isotropic than the molecular layer due to structural differences between the two layers.