Cortical mechanisms that augment or reduce evoked potentials in cats.

The augmenting or reducing of flash-evoked potentials in paralyzed cats was significantly correlated with their previously videotaped behaviors. Augmenting reducing was due to alterations in cortical rather than subcortical responsiveness, and was duplicated by increasing cortical arousal by means of reticular stimulation while the animal was exposed to visual stimuli of constant intensity. Brainstem activation of cortical inhibition may underlie the behavioral results as well as the results obtained with the evoked potentials.