Average spike rate difference maps.

The average spike rate differences at each DU in the respective ROIs are shown for (A) Square and Edge (N = 25), (B) Star (N = 30), and (C) Corners (N = 28). The vertical corner-folds are aligned with the preferred orientation of the neurons. The thick, thin, and dashed purple lines indicate the 0%, 50%, and 100% equal luminance lines. Note that in Star and in Square, the 100% equal luminance line contracts to a single point at the center and so we use a small dotted circle to represent this. The paired arrows indicate the midpoints (50% luminance) of corner-folds (i.e. P180°, S90°, S52° and S40°) where midpoint responses were calculated.