Changes incorporate atrophy in the optic tracts plus the optic chiasm, the optic radiations, the splenium in the corpus callosum (Noppeney et al Shimony et al Pan et al Ptito et al b) plus the inferior longitudinal fasciculus (Ptito et al b), a pathway connecting the occipital cortex with all the temporal lobe.Lesions of this pathway may possibly induce visual agnosia, prosopagnosia, and disturbances in visual current memory (Tusa and Ungerleider,).No studies discovered direct proof for the establishment of new fiber pathways, though volume increases inside the occipitofrontal fasciculus, the superior longitudinal fasciculus and also the genu of the corpus callosum have already been reported (Ptito et al b).There is certainly also indirect evidence for an improved functional connectivity involving somatosensory and visual areas inside the congenitally blind brain (Wittenberg et al Ptito et al Kupers et al).A recent study employing dynamic causal modeling of functional MRI (fMRI) information acquired in the course of an auditory discrimination activity points in the direction of elevated helpful connectivity in between the primary auditory and visual cortices in congenitally blind L-Threonine Autophagy subjects (Klinge et al).Final results with respect to improved thalamocortical connectivity had been inconsistent, arguing against strengthening of thalamocortical connections in congenital blindness.It remains a matter of debate regardless of whether the enhanced connectivity in between the primary visual cortex along with the major auditory and somatosensory cortical regions entails a direct monosynaptic or an indirect polysynaptic pathway by means of multisensory association locations (Fujii et al Klinge et al).Taken with each other, due to the fact no de novo tracts have already been demonstrated in congenitally blind subjects, the data recommend PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/21542694 that crossmodal functionality of the visual cortex in early blindness is primarily mediated by preserved or strengthened corticocortical connections.metAboliC ChAngesThe final results of VBM research have revealed a significant gray matter atrophy of all brain structures on the visual pathways, like the lateral geniculate nucleus (LGN), the posterior pulvinar, the striate and extrastriate visual places and the inferior temporal gyrus and latBesides structural modifications, the occipital cortex of congenitally blind men and women also undergoes crucial metabolic adjustments.We measured brain glucose metabolism by utilizing positron emission tomography (PET) in mixture with fluoroddeoxyglucose (FDG) inside a group of congenitally blind and sighted men and women.We identified that glucose metabolism at rest is enhanced by about in each the striate and the extrastriate cortex of congenitally blind in comparison to sighted folks.Figure C shows restingstate glucose metabolism in representative examples of a congenitallywww.frontiersin.orgFebruary Volume Short article Kupers et al.Blindness and consciousnessFigure Anatomical and metabolic alterations in the congenitally blind brain.(A) Axial brain slices displaying reductions in gray (red) and white matter (blue) in congenitally blind in comparison to matched sighted control subjects.All components with the visual technique in the blind are reduced in volume (after Ptito et al b).(B) Variations in cortical thickness amongst congenitally blind and sighted manage subjects.Regardless of a reductionin volume with the occipital cortex, cortical thickness in the cuneus is improved in congenitally blind subjects (unpublished information from our lab).(C) Midsagittal brain slices showing improved restingstate glucose metabolism within the congenitally blind brain.Ill.
