Visually Evoked Electrocortical Responses in Kittens: Development of Specific and Nonspecific Systems

Visually evoked electrocortical responses were differentiated ontogenetically in young kittens by age of onset, latency, and polarity. A long-latency negative wave, present by 4 days of age and abolished later by lesions of the superior colliculus and pretectal region of the midbrain, is attributed to the non-specific sensory system. A short-latency, positive and negative, diphasic wave, developing by 10 to 15 days of age and blocked by lesion of the lateral geniculate body, is identified with the specific visual system.