Fig. 2.

Example joint tuning function from a single neuron. The joint tuning curve of a neuron recorded from monkey Q is shown in the two-dimensional (2-D) heat map. The hatched region indicates stimulus directions that were not sampled for this neuron because of the nonuniform sampling of directions in neurons recorded from monkey Q (see materials and methods). The luminance scale indicates the firing rate in spikes per second. The individual direction and binocular disparity tuning curves are shown in top and left marginal panels, respectively. The values to the right of each plot indicate the values of the other feature for each tuning curve. The direction tuning curves are shown with the best-fit von Mises functions, and the binocular disparity tuning curves are shown with the best-fit Gabor functions. The binocular disparity tuning curve measured at the preferred direction (120°) and the direction tuning curve at the preferred binocular disparity (0.8°) are shown with the SE around each data point; the SE is smaller than most data points for both tuning curves. This neuron was significantly modulated by stimulus direction when the stimulus was at all binocular disparities and significantly modulated by binocular disparity at all tested stimulus directions.