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.
to draw a direct link between the neuronal responses of the “what” 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 neuron’s preferred, and vice versa.
Fifty-seven disparity selective cells were examined for the predictive
probability of the following monkeys’ 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 “what”
pathway, is functionally involved in fine localization of depth.