Responsiveness of Neurones in the Visual Cortex of Unanesthetized Cats

Abstract

Action potentials were recorded from individual neurones in the visual cortex of unanesthetized cats to determine how these neurones respond to visual stimulation. The retina was stimulated by an oscillating light-dark boundary. Very few consecutive stimulus events are necessary to determine categorically the presence or absence of a response; the summation of the neural activity associated with additional stimulus events is superfluous. No adaptation was observed during sixty seconds of stimulation (180 consecutive stimulus events), although a temporary decline in responsiveness often occurred after the first response. The number of very short intervals between successive discharges was greatly increased during stimulation.