title: Functional subdomains within human FFA.
abstract: The fusiform face area (FFA) is a well-studied human brain region that shows strong activation for faces. In functional MRI studies, FFA is often assumed to be a homogeneous collection of voxels with similar visual tuning. To test this assumption, we used natural movies and a quantitative voxelwise modeling and decoding framework to estimate category tuning profiles for individual voxels within FFA. We find that the responses in most FFA voxels are strongly enhanced by faces, as reported in previous studies. However, we also find that responses of individual voxels are selectively enhanced or suppressed by a wide variety of other categories and that these broader tuning profiles differ across FFA voxels. Cluster analysis of category tuning profiles across voxels reveals three spatially segregated functional subdomains within FFA. These subdomains differ primarily in their responses for nonface categories, such as animals, vehicles, and communication verbs. Furthermore, this segregation does not depend on the statistical threshold used to define FFA from responses to functional localizers. These results suggest that voxels within FFA represent more diverse information about object and action categories than generally assumed.
authors.affiliation: Helen Wills Neuroscience Institute, Program in Bioengineering, and Department of Psychology, University of California, Berkeley, California 94720, and Department of Electrical and Electronics Engineering, Bilkent University, TR-06800 Ankara, Turkey.
authors.forename: Tolga
authors.initials: T
authors.lastname: Çukur
authors.forename: Alexander G
authors.initials: AG
authors.lastname: Huth
authors.forename: Shinji
authors.initials: S
authors.lastname: Nishimoto
authors.forename: Jack L
authors.initials: JL
authors.lastname: Gallant
mesh_terms: D000328:Adult; D001931:Brain Mapping; D005260:Female; D059907:Functional Neuroimaging; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D009778:Occipital Lobe / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000502:physiology; D010775:Photic Stimulation; D013702:Temporal Lobe / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*