Figure 5. Disparity tuning surfaces for 15 example disparity-encoding neurons with different phase disparities and orientations.

Each panel represents the 2D disparity tuning surface for one neuron, that is, the mean spike count elicited from that neuron in response to stimuli with the two-dimensional disparity specified on the horizontal and vertical axes. Specifically, each panel shows W(θ,f,Δφ,Δx_enc;Δx_stim,Δy_stim) (Equation 5), as a function of Δx_stim and Δy_stim, for Δx_enc = 6pix, spatial frequency tuning f = 0.071cyc/pix, and the different θ and Δφ specified in the row/column labels. Each neuron's two-dimensional position disparity (Δx_pos,Δy_pos) is indicated at the top of each panel. This was set as in Equation 1, to ensure its preferred horizontal disparity is Δx_enc (here 6pix) and its preferred vertical disparity is 0. The white cross marks the pixel for which the spike count was highest. The fact that this empirical preferred disparity closely agrees with the desired value (6,0) shows that the position disparity successfully cancels out any vertical component introduced by the phase disparity. Matlab code: The mean response was obtained with Protocol S3, averaging over 500 stimuli, and the figure was generated with Protocol S4.