Alterations of the visual pathways in congenital blindness

TY - JOUR

T1 - Alterations of the visual pathways in congenital blindness

AU - Ptito, Maurice

AU - Schneider, Fabien C G

AU - Paulson, Olaf B

AU - Kupers, Ron

PY - 2008/5/1

Y1 - 2008/5/1

N2 - We used whole brain MRI voxel-based morphometry (VBM) to study the anatomical organization of the visual system in congenitally blind (CB) adults. Eleven CB without a history of visual perception were compared with 21 age- and sex-matched normal-sighted controls (NS). CB showed significant atrophy of the geniculo-striate system, encompassing the optic nerves, the optic chiasm, the optic radiations and the primary visual cortex (BA17). The volume decrease in BA17 reached 25% in both hemispheres. The pulvinar and its projections to the associative visual areas were also dramatically altered, BA18/19 and the middle temporal cortex (MT) showing volume reductions of up to 20%. Additional significant white matter alterations were observed in the inferior longitudinal tract and in the posterior part of the corpus callosum, which links the visual areas of both hemispheres. Our data indicate that the afferent projections to the visual cortex in CB are largely atrophied. Despite the massive volume reductions in the occipital lobes, there is compelling evidence from the literature (reviewed in Noppeney 2007; Ptito and Kupers 2005) that blind subjects activate their visual cortex when performing tasks that involve somatosensory or auditory inputs, suggesting a reorganization of the neural pathways that transmit sensory information to the visual cortex.

AB - We used whole brain MRI voxel-based morphometry (VBM) to study the anatomical organization of the visual system in congenitally blind (CB) adults. Eleven CB without a history of visual perception were compared with 21 age- and sex-matched normal-sighted controls (NS). CB showed significant atrophy of the geniculo-striate system, encompassing the optic nerves, the optic chiasm, the optic radiations and the primary visual cortex (BA17). The volume decrease in BA17 reached 25% in both hemispheres. The pulvinar and its projections to the associative visual areas were also dramatically altered, BA18/19 and the middle temporal cortex (MT) showing volume reductions of up to 20%. Additional significant white matter alterations were observed in the inferior longitudinal tract and in the posterior part of the corpus callosum, which links the visual areas of both hemispheres. Our data indicate that the afferent projections to the visual cortex in CB are largely atrophied. Despite the massive volume reductions in the occipital lobes, there is compelling evidence from the literature (reviewed in Noppeney 2007; Ptito and Kupers 2005) that blind subjects activate their visual cortex when performing tasks that involve somatosensory or auditory inputs, suggesting a reorganization of the neural pathways that transmit sensory information to the visual cortex.

KW - Adult

KW - Aged

KW - Atrophy

KW - Blindness

KW - Brain

KW - Corpus Callosum

KW - Female

KW - Geniculate Bodies

KW - Humans

KW - Image Processing, Computer-Assisted

KW - Magnetic Resonance Imaging

KW - Male

KW - Middle Aged

KW - Neuronal Plasticity

KW - Optic Nerve

KW - Pulvinar

KW - Sensory Deprivation

KW - Temporal Lobe

KW - Visual Cortex

KW - Visual Pathways

U2 - 10.1007/s00221-008-1273-4

DO - 10.1007/s00221-008-1273-4

M3 - Journal article

C2 - 18224306

SN - 0014-4819

VL - 187

SP - 41

EP - 49

JO - Experimental Brain Research

JF - Experimental Brain Research

IS - 1

ER -