Shape similarity is an organizing principle in human object-selective cortex

Functional magnetic resonance imaging (fMRI) has revealed that object-selective regions in human cortex are organized in terms of the category objects belong to. However, exemplars from familiar object categories differ in many respects, including shape, meaning, and the type of processes that are evoked during visual processing. We performed an fMRI study (N=9) that was designed to directly show that the organization of the object vision pathway is related to shape similarity. We designed a stimulus set with 9 novel object categories that varied greatly in shape properties. In a separate behavioral experiment, subjects rated the perceived shape similarity among these objects. The fMRI study showed that objects that were rated as having a similar shape were associated with a very similar pattern of response in object-selective cortex, whereas objects that were rated as being very different in object shape were associated with a more-different pattern of response. These findings demonstrate that shape similarity by itself is an organizing principle in human object-selective cortex.status: publishe