Abstract
Recent studies suggest that face selective regions in the fusiform gyrus undergo a prolonged development involving substantial increases in their spatial extent after age 7 years. It is unknown if this development is sensitive to recent visual experience with own-age faces or cumulative experience with faces of any age. Thus,we examined the development of responses to own- vs. other-age faces in the ventral temporal cortex of children (7 – 11 year olds, n = 10), adolescents (12 – 16 year olds, n = 11) and adults (18 – 40 year olds, n =12). Images of child and adult faces, objects and places were presented in pseudo-randomly ordered blocks in 2 runs, during functional magnetic resonance imaging (fMRI) in a 3T scanner. Subjects fixated and performed a 1-back task. We drew the anatomical boundaries of the fusiform (FUS) and parahippocampal (PHG) gyri and defined face-selective regions (adult & child faces > objects, p <10-3) on each subject’s gray matter. We found that regardless of the age of face stimuli the volume of the face-selective regions in FUS were substantially larger in adults than in children or teens. Importantly, distributed responses in the FUS, outside face-selective regions showed significantly higher correlations (between runs 1 and 2) and higher classification accuracy for adult faces than for child faces, in adults only. Meanwhile, correlation and classification accuracy for child faces were similar among children and adults. These effects were regionally specific, as there were no age effects in distributed responses of the PHG or of face selective regions in FUS. Together, these results suggest an interaction between age-of-subject and age-of-face stimuli among the weakly face-selective voxels of FUS, consistent with a prolonged development of face selectivity during childhood and adolescence that may depend on the exposure and social relevance of various types of faces.
Meeting abstract presented at VSS 2012