Abstract
Our visual memory percepts of whether we have encountered specific objects or scenes before are hypothesized to manifest as decrements in neural responses in inferotemporal cortex (IT) with stimulus repetition. To evaluate this proposal, we recorded IT neural responses as two monkeys performed variants of a single-exposure visual memory task designed to measure the rates of forgetting with time and the robustness of visual memory to a stimulus parameter known to also impact IT firing rates, image contrast. We found that a strict interpretation of the repetition suppression hypothesis could not account for the monkeys' behavior, however, a weighted linear read-out of the IT population response accurately predicted forgetting rates, reaction time patterns, individual differences in task performance and contrast invariance. Additionally, the linear weights were largely all the same-sign and consistent with repetition suppression. These results suggest that behaviorally-relevant memory information is in fact reflected in via repetition suppression in IT, but only within an IT subpopulation.
Meeting abstract presented at VSS 2018