Vincent Lee1, Amy C. Nau2, 3, Kevin C. Chan4, 5
1Department of Radiology, University of Pittsburgh, Pittsburgh, PA, United States; 2Sensory Substitution Laboratory, University of Pittsburgh, Pittsburgh, PA, United States; 3Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, United States; 4Departments of Ophthalmology and Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States; 5Center for the Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, Pittsburgh, PA, United States
This study explored the effect of blindness on visual brain reorganization by analyzing the microstructural changes in fiber architecture in both congenitally blind and acquired blind individuals using diffusion tensor MR imaging. The fractional anisotropy maps from the experimental groups and normally sighted individuals were processed and registered using tract based spatial statistics and evaluated using both voxel-wise and region-of-interest (ROI) based non-parametric analyses. The voxel-wise non-parametric tests uncovered statistically significant FA differences in the bilateral optic radiation and in other major fiber tracts associated with visual processing. ROI based analysis showed that both congenitally blind and acquired blind subjects had lower FA than normal controls in the major fiber tracts connected to the visual cortex. Our results suggested that plastic changes may occur in both early blindness and late onset of blindness after completion of traditional critical period of visual brain development.