Responsiveness of inferotemporal single units to visual pattern stimuli in monkeys performing discrimination.

Four monkeys were trained to choose two rewarded stimuli from four two-dimensional patterns presented successively, and the responsiveness of single units to these patterns was investigated. Eighty-three of 214 units (39%) recorded from the dorsolateral portion of the inferotemporal cortex were responsive; nearly half responded to all four patterns, irrespective of pattern shape and of whether the stimuli were rewarded or not. A few units were responsive to only one of the patterns, regardless of size, color, or luminance, and unresponsiveness to components of the response-eliciting patterns was indicated in some of these units. The activity of most units response to two or three patterns was dependent on pattern shapes rather than the learnt meaning of the patterns.