A neural basis for visual search in inferior temporal cortex.

We often search for a face in a crowd or for a particular object in a cluttered environment. In this type of visual search, memory interacts with attention: the mediating neural mechanisms should include a stored representation of the object and a means for selecting that object from among others in the scene. Here we test whether neurons in inferior temporal cortex, an area known to be important for high-level visual processing, might provide these components. Monkeys were presented with a complex picture (the cue) to hold in memory during a delay period. The cue initiated activity that persisted through the delay among the neurons that were tuned to its features. The monkeys were then given 2-5 choice pictures and were required to make an eye movement to the one (the target) that matched the cue. About 90-120 milliseconds before the onset of the eye movement to the target, responses to non-targets were suppressed and the neuronal response was dominated by the target. The results suggest that inferior temporal cortex is involved in selecting the objects to which we attend and foveate.