Figure 8.

MT neurons signal absolute, not relative, disparities. A, Disparity-tuning curves for an example neuron are plotted for five different surround disparities. B, For each pair of surround disparities, we calculated the horizontal shift between disparity tuning curves by fitting a pair of Gabor functions. From this paired fit, we calculated a shift ratio (see Materials and Methods). C, Distribution of shift ratios for 201 surround pairings from 45 neurons. Note that shift ratios are distributed around zero, with a slight but significant bias toward positive values (sign test, p < 0.0001). Filled bars denote shift ratios that were significantly different from zero (Sequential F test, p < 0.05; 52 of 201 shifts). Error bars indicate SE.