Kevin Weiner
Graduate Student

Repetition suppression and category selectivity in the human ventral stream

Along with Kalanit and Joakim, we are investigating the relationship between repetition suppression (RS) and category selectivity in the human ventral stream. It is unknown whether RS as measured with fMRI reflects reduced firing of the neural populations responding to the repeated stimulus (referred to as "the scaling model"), or whether RS reflects a reorganization of the neural representation in which less neurons respond to repeated stimuli and the tuning of neurons selective to the stimulus becomes narrower (referred to as "the sharpening model"). To examine these two models, we are using block and event-related designs with high-resolution fMRI using faces, bodyparts, flowers, cars, guitars, and houses as target stimuli. Currently, we are finding evidence that RS occurs to the category of interest as well as to non-selective categories within category-selective areas along the ventral stream defined from independent localizer scans. Overall, our data supports the scaling model in which RS as measured with fMRI reflects reduced responses to specific stimuli in proportion to the initial response to the stimuli.