Gross topographic organization in the corpus callosum is preserved despite abnormal visual input

Andrew Bock

(University of Washington)

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Date: May 16, 2014


The loss of sensory input early in development has been shown to induce dramatic anatomical and functional changes within the central nervous system. Using probabilistic diffusion tractography, we examined the retinotopic organization of splenial callosal connections within early blind, anophthalmic, achiasmatic and control subjects. Early blind subjects experience prenatal retinal “waves” of spontaneous activity similar to those of sighted subjects, and only lack postnatal visual experience. In anophthalmia, the eye is either absent or arrested at an early prenatal stage, depriving these subjects of both pre- and postnatal visual input, while in achiasma there is a lack of crossing at the optic chiasm such that the white matter projection from each eye is ipsilateral. Comparing these groups provides a way of separating the influence of pre- and postnatal retinal deprivation and abnormal visual input on the organization of visual connections across hemispheres. We found that retinotopic mapping within the splenium was not measurably disrupted in any of these groups compared to visually normal controls. These results suggest that neither prenatal retinal activity nor postnatal visual experience plays a role in the large-scale topographic organization of visual callosal connections within the splenium, and the general method we describe provides a useful way of quantifying the organization of large white matter tracts.

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Speaker: Andrew Bock, University of Washington

Authors: Melissa Saenz, University of Laussane; Holly Bridge, Oxford; Ione Fine, University of Washington.

Created: Friday, May 23rd, 2014