Selectivity for the configural cues that identify the gender, ethnicity, and identity of faces in human cortex.

We used psychophysical and functional MRI (fMRI) adaptation to examine how and where the visual configural cues underlying identification of facial ethnicity, gender, and identity are processed. We found that the cortical regions showing selectivity to these cues are distributed widely across the inferior occipital cortex, fusiform areas, and the cingulate gyrus. These regions were not colocalized with areas activated by traditional face area localizer scans. Traditional face area localizer scans isolate regions defined by stronger fMRI responses to a random series of face images than to a series of non-face images. Because these scans present a random assortment of face images, they presumably produce the strongest responses within regions containing neurons that are face-sensitive but not highly tuned for face type. These areas might be expected to show only weak selective adaptation effects. In contrast, the largest responses to our selective adaptation paradigm would be expected within areas containing more selectively tuned neurons that might be expected to show only a sparse collective response to a series of random faces. Many aspects of face processing (e.g., prosopagnosia, recognition, and configural vs. featural processing) are likely to rely heavily on regions containing high proportions of neurons that show selective tuning for faces.