Spatial Synchronization of Cortical and Subcortical Potentials in Rabbits During Formation of Conditioned Reflexes

Abstract

Among the various changes which recent investigations have revealed in cortical electrical activity during formation of conditioned reflexes, attention has been drawn to the regular changes in spatial synchronization of potentials in different parts of the cortex. The extensive spread of synchronized rhythms over the cortex observed by Livanov and Polyakov (1945) in the course of formation of a conditioned connection led to the suggestion that spatial spread of similar potentials may occur over the cerebral cortex. An increase in similarity between potentials under such conditions, even in the absence of synchronized rhythms, was found by Dumenko (1953a, 1955). Similar results were obtained by electrophysiological investigations of conditioned-reflex formation in dogs (Verzilova, 1958; Dumenko, 1960, 1965). Further analysis of this phenomenon (Knipst et al., 1959; Knipst, 1960) showed that the degree of spatial synchronization of cortical potentials varies with the phases of conditioning. Formation of a conditioned reflex in rabbits also led to the appearance of similarity between potentials at different levels of the cortex whose activity exhibits characteristic differences from animals in a resting state (Knipst, 1955, 1958).