Early blindness is associated with increased volume of the uncinate fasciculus.

Abstract

Growing evidence demonstrates dramatic structural and functional neuroplastic changes in individuals born with early-onset blindness. For example, cross-modal sensory processing at the level of the occipital cortex appears to be associated with adaptive behaviors in the blind. However, detailed studies examining the structural properties of key white matter pathways in other regions of the brain remain limited. Given that blind individuals rely heavily on their sense of hearing, we examined the structural properties of two important pathways involved with auditory processing, namely the uncinate and arcuate fasciculi. High angular resolution diffusion imaging (HARDI) tractography was used to examine structural parameters (i.e., tract volume and quantitative anisotropy, or QA) of these two fasciculi in a sample of 13 early blind individuals and 14 normally sighted controls. Compared to controls, early blind individuals showed a significant increase in the volume of the left uncinate fasciculus. A small area of increased QA was also observed halfway along the right arcuate fasciculus in the blind group. These findings contribute to our knowledge regarding the broad neuroplastic changes associated with profound early blindness.