Figure 1.

Visual stimulus and the stereoacuity task. a, In each experiment, one of nine shapes that elicited the best response at zero-disparity was used in the task. Scale bar, 3°. b, The task schedule. The dotted square shows the fixation window, which was not actually visible. Monkeys were trained to make a leftward saccade for uncrossed (far) disparities and a rightward saccade for crossed (near) disparities. c, Behavioral performance from both monkeys. The proportion of far choices is plotted as a function of horizontal disparity. In addition to binocular (•) presentations, monocular (▵, left eye; ▿, right eye) presentations were tested. deg, Degree. d, Histological reconstruction of the recording site in monkey 1. Monkey 2 was still used in a different experiment, but the recording chamber was placed in a similar position. st, Superior temporal sulcus; amt, anterior middle temporal sulcus.