Virtual fMRI brown bag: April 2, 2021

Please join us for a talk given by Pinglei Bao, an assistant professor at Peking University.

The similar object spaces are represented in the primate IT cortex and deep learning networks

Abstract: The inferotemporal (IT) cortex is responsible for object recognition. However, the functional organization of this part of the brain is still unclear. It is known that several category-selective areas exist in the IT cortex, such as face, body and scene network, but large parts of IT cortex lack any known specialization, raising the question of whether any general principle governs IT organization. One key challenge is to develop a way to parametrize arbitrary objects in a high-level. Here we built a low-dimensional object space to describe general objects using a feedforward deep neural network trained on object classification. With the object space, we used functional MRI, microstimulation and electrophysiology to investigate the organization of macaque IT cortex. Responses of IT cells to a large set of objects revealed that single IT cells project incoming objects onto specific axes of the object space. Anatomically, cells were clustered into four networks according to the first two components of their preferred axes, forming a map of object space. This map was repeated across three hierarchical stages of increasing view invariance, and cells that comprised these maps collectively harboured sufficient coding capacity to approximately reconstruct objects. These results provide a unified picture of IT organization in which category-selective regions are part of a coarse map of object space.