Modulation of the face- and body-selective visual regions by the motion and emotion of point-light face and body stimuli

Abstract

Neural regions selective for facial or bodily form also respond to facial or bodily motion in highly form-degraded point-light displays. Yet it is unknown whether these face-selective and body-selective regions are sensitive to human motion regardless of stimulus type (faces and bodies) or to the specific motion-related cues characteristic of their proprietary stimulus categories. Using fMRI, we show that facial and bodily motions activate selectively those populations of neurons that code for the static structure of faces and bodies. Bodily (vs. facial) motion activated body-selective EBA bilaterally and right but not left FBA, irrespective of whether observers judged the emotion or color-change in point-light angry, happy and neutral stimuli. Facial (vs. bodily) motion activated face-selective right and left FFA, but only during emotion judgments for right FFA. Moreover, the strength of responses to point-light bodies vs. faces positively correlated with voxelwise selectivity for static bodies but not faces, whereas the strength of responses to point-light faces positively correlated with voxelwise selectivity for static faces but not bodies. Emotional content carried by point-light form-from-motion cues was sufficient to enhance the activity of several regions, including bilateral EBA and right FFA and FBA. However, although the strength of emotional modulation in right and left EBA by point-light body movements was related to the degree of voxelwise selectivity to static bodies but not static faces, there was no evidence that emotional modulation in fusiform cortex occurred in a similarly stimulus category-selective manner. This latter finding strongly constrains the claim that emotionally expressive movements modulate precisely those neuronal populations that code for the viewed stimulus category.