Big and small objects are represented in a medial to lateral organization across ventral visual cortex

Konkle & Oliva

The physical size of objects determines our interaction with them: we handle small objects (glass, calculator), and we move around large-scale objects (chair, piano). Here, we find that this functional dissociation is reflected in distinct neural activity patterns across the ventral visual cortex of adult human observers. Observers were shown pictures of objects with known small and large sizes (e.g. strawberry vs piano) presented at the same retinal size on the screen. A bilateral region in the parahippocampal gyrus was preferentially active to big objects versus small objects, while an adjacent left-lateralized subregion in inferior temporal cortex as well as a region on that lateral occipital temporal cortex were preferentially active to small versus big objects. Control experiments show that these regions are not driven by any specific object categories, are robust to changes in retinal size, and respond systematically during mental imagery. In subsequent mapping experiments examining known size, a smooth continuum across the range of object size was seen in half the observers, while a more categorical (big-medial/small-lateral) organization was seen in the remaining participants. These results show objects of big and small known real-world sizes preferentially activate anterior ventral visual cortex in a medial to lateral organization, respectively, suggesting that the real-world size of objects may be an informative property for characterizing the organization of visual object knowledge along ventral visual cortex.

Konkle, T., & Oliva, A. (2011). Big and small objects are represented in a medial to lateral organization across ventral visual cortex. Talk to be presented at the Concepts, Actions, and Objects annual meeting, May 19-22, Rovereto, Italy.