Training in radiology dramatically changes observers' ability to process images, but the neural bases of this visual
expertise remain unexplored. Prior imaging work has suggested that the fusiform face area (FFA), normally selectively
responsive to faces, becomes responsive to images in observers' area of expertise. The FFA has been hypothesized to be
important for "holistic" processing that integrates information across the entire image. Here, we report a cross-sectional
study of radiologists that used functional magnetic resonance imaging to measure neural activity in first-year radiology
residents, fourth-year radiology residents, and practicing radiologists as they detected abnormalities in chest radiographs.
Across subjects, activity in the FFA correlated with visual expertise, measured as behavioral performance during
scanning. To test whether processing in the FFA was holistic, we measured its responses both to intact radiographs and
radiographs that had been divided into 25 square pieces whose locations were scrambled. Activity in the FFA was equal
in magnitude for intact and scrambled images, and responses to both kinds of stimuli correlated reliably with expertise.
These results suggest that the FFA is one of the cortical regions that provides the basis of expertise in radiology, but that
its contribution is not holistic processing of images.