Figure 4.

Distribution of selectivity for luminance- and texture-defined form in V2. Each point represents a single neuron (N = 128); its position relative to each edge of the triplot represents how well each family of response predictions (first-order, second-order, and an “intermediate” family of modulated responses: modulated by motion or form) can account for the observed herringbone tuning (for more detail, see Materials and Methods). The points are color-coded by the log likelihood of the best prediction (compare Fig. 3, column 5); darker shades represent higher likelihoods. Most neurons were best described by the first-order prediction, some cells fell into the intermediate category, whereas only a handful of cells were best described by the second-order prediction. The second-order neuron marked as an open circle is the only cue-invariant neuron we recorded in V2 (Fig. 3D).