Within-Subject Reproducibility of Category- Specific Visual Activation With Functional MRI

Abstract: We used functional magnetic resonance imaging (fMRI) to investigate within-subject reproduc-ibility of activation in higher level, category-specific visual areas to validate the functional localization approach widely used for these areas. The brain areas investigated included the extrastriate body area (EBA), which responds selectively to human bodies, the fusiform face area (FFA) and the occipital face area (OFA), which respond selectively to faces, and the parahippocampal place area (PPA), which responds selectively to places and scenes. All six subjects showed significant bilateral activation in the four areas. Reproducibility was very high for all areas, both within a scanning session and between scanning sessions separated by 3 weeks. Within sessions, the mean distance between peak voxels of the same area localized by using different functional runs was 1.5 mm. The mean distance between peak voxels of areas localized in different sessions was 2.9 mm. Functional reproducibility, as expressed by the stability of T-values across sessions, was high for both within-session and between-session comparisons. We con-clude that within subjects, high-level category-specific visual areas can be localized robustly acros