Electrocortical correlates of stimulus response and reinforcement

Three patterns of electrical response were identified in the occipital cortex of rhesus monkeys making a differential discrimination: an input pattern that identifies which stimulus has been displayed; a reinforcement pattern that indicates whether the outcome of the differential response was rewarded or in error; and an intention pattern that occurs prior to the response and predicts which response the monkey is about to make. Neither the reinforcement nor the intention pattern is present while the monkeys perform at chance; at this time, only the differences due to input can be distinguished. These results suggest that more than simple input transmission is occurring in the primary visual mechanism. The influence of the experience of the organism is apparently encoded in the averaged electrical potentials recorded from the striate cortex.