Prediction suppression in monkey lerinferotemporal cortex depends on the conditional probability between images

When monkeys view two images in fixed sequence repeatedly over days and weeks, neurons in area TE of the inferotemporal cortex come to exhibit prediction suppression. The trailing image elicits only a weak response when presented following the leading image that preceded it during training. Induction of prediction suppression might depend either on the contiguity of the images, as determined by their co-occurrence and captured in the measure of joint probability P(A, B), or on their contingency, as determined by their correlation and as captured in the measures of conditional probability P(A vertical bar B) and P(B vertical bar A). To distinguish between these possibilities, we measured prediction suppression after imposing training regimens that held P(A, B) constant but varied P(A vertical bar B) and P(B vertical bar A). We found that reducing either P(A vertical bar B) or P(B vertical bar A) during training attenuated prediction suppression as measured during subsequent testing. We conclude that prediction suppression depends on contingency, as embodied in the predictive relations between the images, and not just on contiguity, as embodied in their co-occurrence.