Correlated variability of stereoscopic depth judgments and neural responses in monkey inferior-temporal cortex

3T. Uka, 2S. Tanabe, 2M. Watanabe, and 1,3I. Fujita

1Grad. Sch. of Frontier Biosciences and 2Grad. Sch. of Engineering Science, Osaka Univ.; 3CREST, JST, Osaka, Toyonaka, 560-8531.

In order to draw a direct link between the neuronal responses of the gwhath pathway and stereoscopic depth perception, we examined responses of neurons in the inferior-temporal (IT) cortex while monkeys were discriminating fine binocular disparity. The trial-to-trial fluctuation of responses of IT neurons correlated with the choice the monkeys made. When cells responded at a higher firing rate than the overall average for that disparity, the monkeys tended to judge the disparity of the stimulus toward the neuronfs preferred, and vice versa. Fifty-seven disparity selective cells were examined for the predictive probability of the following monkeysf choice. The mean choice probability was 0.57 and 31/57 neurons had choice probabilities significantly above 0.5. The present results suggest that the IT, an area belonging to the gwhath pathway, is functionally involved in fine localization of depth.