Figure 3. RS by Stimulus Type in the ventral stream.

(A) Large bilateral regions encompassing medial and lateral regions of the fusiform gyrus were defined by the presence of a main effect of RS (both ps < .002), collapsing across the factor Stimulus Type (left to right, axial views at z = -17, -12, and -7). Consistent with the broad expanse of highlighted structures, there were main effects of Stimulus Type (ps < .0001) in both the left and right hemispheres. The interaction between RS and Stimulus Type was significant in the right hemisphere (p < .041), and there was a trend in the left hemisphere (p = .09). The peak TT coordinates for this contrast were -36, -57, -8 (left hemisphere) and 32, -46, -6 (right hemisphere). (B) The distinct colors represent RS (p < .01) biased toward each of the four Stimulus Types. We also coded voxels that showed RS biased toward both ‘tools’ and arbitrarily manipulated objects, in order to study potential overlap in RS effects for the two types of manipulable objects. As depicted in Figure 3B (left to right, axial views at z = -17, -12, and -7), the largest regions, located in the medial fusiform gyri bilaterally, showed RS biased toward ‘tools’ (blue). In addition, smaller clusters of voxels showing RS biased toward arbitrarily manipulated objects (yellow), and toward both ‘tools’ and arbitrarily manipulated objects (green), were also observed. RS was biased toward animals (red) in the right lateral fusiform gyrus. RS biased toward nonmanipulable objects (cyan) was restricted to parahippocampal cortex. This effect for nonmanipulable objects was present bilaterally (only right hemisphere activation shown). (C – E) Histograms represent RS effects (difference scores: novel – repeated) for each experimental condition, for the left (red bars) and right (green bars) medial fusiform gyrus. The corresponding functional group maps are shown (colored blue) next to each histogram (y = -42). As can be seen, RS was observed for ‘tools’ in the medial fusiform gyrus bilaterally, independently of how this region was defined. For further details of the analyses, see Supplemental Table S2; for histograms showing overall BOLD responses for the same contrasts, see Supplemental Figure S1. (C) Voxels in the medial fusiform gyrus showing greater activation for ‘tools’ than animals (p < .01). (D). Voxels in the medial fusiform gyrus showing greater activation for arbitrarily manipulated objects than animals (p < .01). (E). Voxels in the medial fusiform gyrus showing greater activation for nonmanipulable objects than animals (p < .01).