%0 Journal Article
%T Altered White Matter Integrity in the Congenital and Late Blind People
%A Dawei Wang
%A Wen Qin
%A Yong Liu
%A Yunting Zhang
%A Tianzi Jiang
%A Chunshui Yu
%J Neural Plasticity
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/128236
%X The blind subjects have experienced a series of brain structural and functional alterations due to the visual deprivation. It remains unclear as to whether white matter changes differ between blind subjects with visual deprivation before and after a critical developmental period. The present study offered a direct comparison in changes of white matter fractional anisotropy (FA) between congenital blind (CB) and late blind (LB) individuals. Twenty CB, 21 LB (blindness onset after 18 years old), and 40 sight control (SC) subjects were recruited. Both the tract-based spatial statistics (TBSS) and voxel-based analysis (VBA) showed lower FA in the bilateral optic radiations in both blind groups, suggesting that the loss of white matter integrity was the prominent hallmark in the blind people. The LB group showed more extensive white matter impairment than the CB group, indicating the mechanisms of white matter FA changes are different between the CB and LB groups. Using a loose threshold, a trend of an increased FA was found in the bilateral corticospinal tracts in the LB but with a smaller spatial extent relative to the CB. These results suggest that white matter FA changes in the blind subjects are the reflection of multiple mechanisms, including the axonal degeneration, deafferentation, and plasticity. 1. Introduction The blind subjects, irrespective of the age of onset, have experienced a series of structural and functional alterations, and they have to make major adjustments to interact effectively with the environment. Numerous functional magnetic resonance imaging (fMRI) studies have revealed that the occipital cortex of the blind subjects shifts its function to process tactile [1] and auditory information [2] and to engage in many higher-level cognitive functions, such as language [3每8], memory [3], and mental imagery [9每11]. Structural MRI studies have shown the decreased gray/white matter volume [12每14] but increased cortical thickness in the occipital cortex [15, 16]. During the past two decades, diffusion tensor imaging (DTI), as a noninvasive means, makes the in vivo evaluation of white matter integrity possible using the fractional anisotropy (FA) [17每19]. The decreased FA may represent the impairment in white matter integrity, in contrast, the increased FA may indicate the increase in white matter integrity [17每19]. Different DTI analytic methods have shown that congenitally blind (CB) or early blind (EB) subjects had atrophy [20] or decreased white matter integrity [21] in the optic radiation (OR), reduced efficiency of the brain anatomical
%U http://www.hindawi.com/journals/np/2013/128236/