Neuronal correlates of view representation revealed by face-view aftereffect.

Recognition of face-views is a crucial component of our social behavior. However, little is known about the neuronal basis of face-view recognition. Recent psychophysical studies have shown that adaptation to a particular face-view changes perception of other views in humans. To understand the neuronal basis of face-view representation and the mechanisms involved in face-view adaptation, we studied the responses of inferotemporal (IT) cortex neurons before and after face-view adaptation. We first used face-view adaptation to show that monkeys, as well as humans, exhibit face-view aftereffect, suggesting the presence of a view-sensitive representation in primates. Then, we recorded from IT neurons of monkeys and found that changes in responses of these neurons can account for changes in perception of face views attributable to adaptation, indicating IT as a neural correlate of face-view perception. More importantly, we provide evidence that IT neurons with wide-view tuning not only conveyed face-view information but also exhibited neural signatures of view aftereffect before neurons with narrower tuning. Our findings show that view-dependent representation of objects does not necessarily depend on narrow-tuned neurons. The finding that wide-view tuned neurons account for view-specific perceptual changes implies the importance of accumulating sensitivity and tolerance at the level of IT neurons, as the final stage of visual object recognition.