A neural substrate for object permanence in monkey inferotemporal cortex

Abstract

We take it for granted that objects continue to exist after being occluded. This knowledge-known as object permanence-is present even in childhood, but its neural basis is not fully understood. Here, we show that monkey inferior temporal (IT) neurons carry potential signals of object permanence even in animals that received no explicit behavioral training. We compared two conditions with identical visual stimulation: the same object emerged from behind an occluder as expected following its occlusion, or unexpectedly after occlusion of a different object. Some neurons produced a larger (surprise) signal when the object emerged unexpectedly, whereas other neurons produced a larger (match) signal when the object reappeared as expected. Neurons carrying match signals also reinstated selective delay period activity just before the object emerged. Thus, signals related to object permanence are present in IT neurons and may arise through an interplay of memory and match computations.