Visual evoked potentials in response to pattern reversal in the cat cortex.

A model of the visually evoked potential (VEP) in the cerebral cortex of the cat after binocular stimulation by means of pattern reversal is presented. The VEP is defined by four components: P1, N1, P2 and N2, which appear during the 100 ms following the stimulus. This model is repeated for the majority of recording points although N1 and P2 do not appear to be homogeneous over the entire cortex. The variability of the VEPs recorded at the same point in different cats is lower than the one observed by means of stimulation with flashes. The possible origin of the four components in the primary visual area is presented as a hypothesis and a discussion is made of the differences which exist between the models proposed for flash and pattern reversal.