Thursday, March 15, 2007

Activity of Inferior Temporal Cortical Neurons Predicts Recognition Choice Behavior and Recognition Time during Visual Search

Ryan E. B. Mruczek and David L. Sheinberg
The Journal of Neuroscience, March 14, 2007, 27(11):2825-2836; doi:10.1523/JNEUROSCI.4102-06.2007

Although the selectivity for complex stimuli exhibited by neurons in inferior temporal cortex is often taken as evidence of their role in visual perception, few studies have directly tested this hypothesis. Here, we sought to create a relatively natural task with few behavioral constraints to test whether activity in inferior temporal cortex neurons predicts whether or not a monkey will recognize and respond to a complex visual object. Monkeys were trained to freely view an array of images and report the presence of one of many possible target images previously associated with a hand response. On certain trials, the identity of the target was swapped during the monkeys' targeting saccade. Furthermore, the response association of the preswap target and the postswap target differed (e.g., right-to-left target swap). Neural activity in cells selective for the preswap target was significantly higher when the monkeys' response matched the hand association of the preswap target. Furthermore, the monkeys' response time was predicted by the magnitude of the presaccadic firing rate on nonswap trials. Our results provide additional support for the role of inferior temporal cortex in object recognition during natural behavior.


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