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.

[1]  W. Landau,et al.  Some relations between resistivity and electrical activity in the cerebral cortex of the cat. , 1955, Journal of cellular and comparative physiology.

[2]  Stanley Rush,et al.  Methods of measuring the resistivities of anisotropic conducting media in situ , 1962 .

[3]  A. van Harreveld,et al.  Specific impedance of rabbit's cortical tissue. , 1963, The American journal of physiology.

[4]  J. B. Ranck,et al.  Specific impedance of rabbit cerebral cortex. , 1963, Experimental neurology.

[5]  J. B. Ranck,et al.  Analysis of specific impedance of rabbit cerebral cortex. , 1963, Experimental neurology.

[6]  N. H. Sabah,et al.  Cerebellar Purkinje cell responses to afferent inputs. I. Climbing fiber activation. , 1971, Brain research.

[7]  H C Kwan,et al.  A basis for extracellular current density analysis in cerebellar cortex. , 1974, Journal of neurophysiology.

[8]  J. Szentágothai,et al.  Quantitative histological analysis of the cerebellar cortex in the cat. I. Number and arrangement in space of the Purkinje cells. , 1971, Brain research.

[9]  J Szentágothai,et al.  Quantitative histological analysis of the cerebellar cortex in the cat. II. Cell numbers and densities in the granular layer. , 1971, Brain research.

[10]  R Galambos,et al.  Evoked resistance shifts in unanesthetized cats. , 1968, Experimental neurology.

[11]  R Galambos,et al.  Rapid resistance shifts in cat cortex during click-evoked responses. , 1968, Journal of neurophysiology.

[12]  P. Nicholson,et al.  Specific impedance of cerebral white matter. , 1965, Experimental neurology.

[13]  J. B. Ranck,et al.  THE SPECIFIC IMPEDANCE OF THE DORSAL COLUMNS OF CAT: AN INISOTROPIC MEDIUM. , 1965, Experimental neurology.