CNS Seminar May 22nd: Isabel Gauthier from Vanderbilt University
Perceptual expertise and selectivity for faces in the ventral temporal cortex
More than twelve years ago, my colleagues and I found evidence of selective responses to cars in the fusiform face area in the ventral temporal cortex of people with expertise recognizing cars. This has been a central piece of evidence for the claim that the selectivity in the FFA for faces develops as a result of our experience with faces. Since then, high-resolution fmri (HR-fMRI) and fMRI-guided neurophysiology in the monkey have suggested no reliable selectivity for non-face objects in the FFA or its monkey homologue. One can therefore ask whether expertise effects may simply be due to spatial blurring from non face-selective voxels. Using HR-fMRI at 7Tesla, we found evidence for robust expertise effects within the most face-selective voxels at the peak of face-selectivity. These effects were spatially contiguous with face responses, and the selectivity of these voxels for face relative to other objects actually decreased as a function of expertise in the most anterior part of the FFA (FFA-2). I will also report on other work at 7T and 3T that reveal how this part of the FFA shows the most robust expertise effects when a task becomes more attentionally demanding, and that expertise effects for non-face objects are robust in FFA in conditions of inattention but are reduced when presented among objects for which they compete for perceptual resources. In sum, I will argue that face-selectivity in VTC is best studied as a instance of perceptual expertise, a framework that gives us a handle on specialization for different categories more generally across the visual system.