Abstract
The remarkable selectivity of some cells in inferior temporal cortex (IT) suggests that these cells contribute to the perceptual awareness of complex visual images. However, few studies have tested the relationship between neural activity in IT and behavioral performance. Those that have explored this relationship have concentrated on extended displays of ambiguous stimuli. Here, we sought to create a relatively natural task with few behavioral constraints to test whether neurons in IT fire more robustly when a monkey recognizes and responds to a complex visual object.
A monkey was trained to freely view an array of images and locate one of many possible target images previously associated with one of two button presses. On normal trials, the monkey naturally made a saccade to the target image and pressed the appropriate button. On swap trials, the identity of the target was changed during the monkey's targeting saccade. Furthermore, the response association of the pre-swap target and the post-swap target differed (i.e. left target swapped to right target).
We can infer that the monkey noticed the pre-swap target if his manual response matched the association of the pre-swap target. Neural activity in cells selective for the pre-swap target was significantly higher when the monkey recognized that target. Furthermore, the monkey's response time was predicted by the magnitude of the presaccadic firing rate on normal trials. Our results provide direct support for the role of IT in visual awareness during natural behavior.