Figure 6. Average population response, W(θ,f,Δφ,Δx_enc;Δx_stim,Δy_stim), for different stimulus vertical disparities.

Only neurons with zero phase disparity are shown (the key features discussed in the text are the same for all phase disparities). The stimulus disparity is fixed in each panel, and the horizontal axis is the preferred horizontal disparity of the neurons (unlike Figure 5, where the neuron's preferred horizontal disparity was fixed in each panel and the horizontal axis was the horizontal disparity of the stimulus). Each panel shows the mean number of spikes which stimuli with this disparity elicit from 126 neurons, tuned to 21 different horizontal disparities Δx_enc and 6 orientations θ, plotted on the horizontal and vertical axes respectively. The 5 panels in each row show sets of 126 neurons tuned to 5 different preferred spatial frequencies. Thus together each row shows the mean response of the zero-phase-disparity sub-population, 630 neurons, averaged over 500 random stimuli with the same stimulus disparity. The stimulus horizontal disparity, Δx_stim, was set equal to −2 pixels throughout (marked with the arrow in each panel); the stimulus vertical disparity, Δy_stim, was set to a different value in each row, as indicated to the left of each row. The colorscale is the same as in Figure 5, indicated on the right. Matlab code: The mean responses were obtained with Protocol S3, and the figure was generated with Protocol S5.