Abstract
Human high-level visual cortex contains a constellation of functionally defined regions showing preferential neural responses to specific categories of visual stimuli, such as face-selective regions in the fusiform gyrus (FFA). While our lab has demonstrated that the development of the FFA correlates with face recognition memory from childhood to adulthood, how the concurrent development of neighboring white matter relates is still unclear. We used diffusion tensor imaging (DTI) in 13 children (aged 7-11), 11 adolescents (aged 12-16), and 9 adults (aged 18-40) to deterministically track visual association fibers connecting the occipital lobe to the anterior temporal lobe (inferior longitudinal fasciculus, ILF) and to the frontal lobe (inferior fronto-occipital fasciculus, IFOF). We then correlated resultant fiber properties (fractional anisotropy (FA), radial (RD) and mean diffusivity (MD)) with several behavioral measures, including the Benton face perception task, recognition memory tasks for faces, places, objects, and cars, and the abbreviated scale of intelligence (WASI). Anatomically, we observed prolonged development of both the ILF and IFOF in both hemispheres, with FA significantly lower in children than adults (Fs > 5.1 , ps < .01). Behaviorally, performance on the Benton face perception task was the only measure that showed a significant correlation with white matter properties across subjects. Specifically, there was a significant correlation between Benton performance and FA values of the right ILF, even after controlling for the effect of age (r = .58, p = .01). This correlation was highest in posterior portions of the ILF and decreased anteriorly. These results demonstrate that large fiber tracts connecting the ventral stream to the anterior temporal and prefrontal lobes undergo prolonged development into adulthood. Moreover, our data suggest that the structural integrity of the right ILF is important for face perception proficiency and that lesions to this tract may impair such perception.
Meeting abstract presented at VSS 2013