[Evoked potentials in the visual and association cortex of alert cats in response to paired homogeneous stimulation of the lateral geniculate body and pulvinar]

Abstract

Similar shape of evoked potentials' recovery curves in the association and visual cortex to paired stimulation of the pulvinar was shown in unrestrained cats. Depression of the test response was observed only at the 10 ms interstimulus interval and powerful (2-4 times) facilitation of the second response occurred at the 40 ms interval as a result of increasing of the negative component N1. The facilitation was less expressed at 60-100 ms intervals gradually decreasing to the interval of 200 ms. Cortical evoked potentials' recovery curve to paired stimulation of the lateral geniculate body differed significantly from that of the pulvinar stimulation and was characterized by a gradual increase of the second response (from its strong depression at 10 ms interval to slight facilitation at 200 ms interval). Slower recovery of the test response in the association cortex was found at 10-80 ms intervals. The data are discussed from the standpoint of intracortical excitation spread as a result of activation of geniculo- and pulvinar-cortical information channels.