Exploring the functional organization of the superior temporal sulcus with a broad set of naturalistic stimuli
23.503, Saturday, 17-May, 8:30 am - 12:30 pm, Pavilion
Ben Deen1, Nancy Kanwisher1, Rebecca Saxe1; 1Department of Brain and Cognitive Sciences and McGovern Institute for Brain Research, MIT
The superior temporal sulcus (STS) has been identified as a critical region for social perception. Prior experiments have used targeted contrasts (e.g., faces versus objects or human motion versus object motion) to investigate the functional organization of the STS. However, the space of visual social stimuli is very broad, and experiments intended to isolate a single feature may miss other dimensions of relevance to the STS. Additionally, while most prior work on the STS has focused on responses of individual voxels or regions of interest, recent fMRI studies in other domains have demonstrated that multivoxel patterns of activity often carry more information than mean responses alone. In the present study, we measured STS responses to 282 dynamic social stimuli (3s-long film clips depicting humans acting and interacting), and related responses and patterns to a number of continuous social dimensions. These dimensions included various types of biological motion (head, hand, eye, and leg motion), the presence of talking, presence of a social interaction, strength of emotions depicted, and emotional valence, with several low-level visual properties (luminance, contrast, and motion) included as controls. Patterns in a common posterior STS region explained unique variance in a number of social perceptual dimensions, including presence of biological motion, the presence of interactions and talking, and strength of emotions. Additionally, the presence of talking was predicted by patterns in multiple regions along the full length of the STS. Across the board, using patterns instead of mean responses improved sensitivity in predicting stimulus features. These results indicate that the pSTS plays a varied role in social perception, with response patterns in this region relating to a number of distinct stimulus dimensions.