Jaime Doyle Title: The age-related emergence of the cortical connectivity underlying face processing revealed by diffusion tensor imaging. Abstract: In adults, face processing is associated with a distributed circuit involving multiple cortical regions, some of which form the 'core', and others which form the 'extended' part of the face-related processing network (Fairhall & Ishai, 2007; Gobbini & Haxby, 2006). fMRI studies reveal reduced face-selectivity in both the core (the FFA, OFA, and STS in adults) and extended (associated anterior regions) network in children, whereas adolescents evince a more adult- like pattern in the core but not extended region (Scherf et al., 2007). To examine the developmental emergence of the structural circuitry of the face- processing network, we used diffusion tensor imaging to asses the integrity of the two major white matter tracts that pass through the fusiform gyrus, the pre-eminent face processing region (Kanwisher et al., 1997), which is effectively connected to other face-related regions. We quantified the macrostructural (density/volume) and microstructural (fractional anisotropy) properties of the two tracts, the inferior longitudinal fasciculus (ILF) and the inferior fronto-occipital fasciculus (IFOF) in children, adolescents, and adults. The findings suggest a significant improvement in the structural integrity of the right ILF as a function of age on all dependent measures. This gives new insight into the structural changes in the cortical regions mediating face perception and may explain the protracted course of acquisition of face selectivity over development.