Statistics of spontaneous electrical activity of supra- and ectosylvian gyri of the dog

¹ Department of Anatomy, University of Oregon Medical School, Portland, Oregon

The standard deviations of the spontaneous electrical activity (SEA) of the suprasylvian gyrus (SSG) ranged between 57–131 µv and for the middle ectosylvian (MES) gyrus, 88–175 µv. Correlation coefficients, r, served to distinguish three regions of the SSG. The rostral showed low correlation with the middle, high correlation with the caudal, and low to negative correlation with the MES. The middle showed moderate correlation with the MES, and the caudal showed zero to negative correlation with the MES. Within the SSG, correlation was low and in the MES high, for spacings of 2 mm. Cocaine applied to both areas sharpened the boundaries at the sulci, reduced standard deviations, did not affect the correlation between the caudal SSG and the MES area, and increased r between all locations in the MES but not in the SSG. Cocaine on the SSG had no effect on the mean and standard deviation of the evoked potential in the MES, but decreased r of the SEA significantly.