Event Abstract Back to Event Retention of perceptual categorization following bilateral removal of area TE in rhesus monkeys Narihisa Matsumoto1, 2*, Richard Saunders1, Katalin Gothard3 and Barry Richmond1 1 NIMH/NIH, Japan 2 NIMH/NIH, AIST, Japan 3 University of Arizona, United States Bilateral ablation of inferior temporal (IT) cortex impairs pattern discrimination in monkeys [1,2]. Single neurons in area TE of IT cortex have marked tuning to visual stimuli like objects or faces [3-5]. Physiological recordings (single neuron and fMRI) show activity grouped into categorical-like functions (face and non-face patches) [6-10]. These findings lead to the hypothesis that area TE plays a critical role in categorizing objects or faces. To test this hypothesis, monkeys were tested before and after bilateral removals of area TE on a task that requires the association of 2 perceptual categories (e.g. human faces vs. monkeys faces) of visual stimuli with different incentive values. In the task the monkey grasps and holds a bar, a visual cue appears for 400 ms, and then a red dot appears in the center of the stimulus, 500-1500 ms later the red dot changes to green. If the monkey releases the bar within 3 seconds after the dot changes to green, the color of the dot changes to blue and in high incentive trials a liquid reward is also delivered. In low incentive trials the trial ends. After an intertrial interval a new cue is chosen pseudorandomly for the next trial. We used 20 dogs/20 cats, or 20 human/20 monkey faces for the visual cues. Before TE ablations, the monkeys made significantly more errors in trials with low incentive stimuli than in trials with high incentive stimuli (p