Fig. 3.

A, Example stimuli used in Experiment 3, varying in both Boundary Type (Concave, Convex) and Angle (1, 2, 3). All Concave and Convex conditions that share the same Angle are equated in the low-level visual information they contain. A “flat” boundary condition was also included, and used as a baseline condition to eliminate an ROI’s baseline response to the presence of a boundary. B, Average percent signal change to the concave and convex boundaries relative to the flat boundary in each region of interest. PPA’s response increases as the concavity of a boundary increases, but not with increasing convexity of a boundary. By contrast, LOC tracks changes in both concavity and convexity of a boundary, but shows a preferential response to convex boundaries. The pattern of response in PPA is qualitatively different from those in V1 and LOC. OPA shows a greater sensitivity to changes in concavity over convexity. We found no significant response pattern in RSC. Error bars represent the standard error of the mean.