Lack of visual experience does not affect the retinotopic organization of visual cortico-callosal connections.

• DOI: 10.1167/12.9.1358
• Publication Date: 2012-08-11T22:39:50Z
• Authors: A. Bock; M. Saenz; G. Boynton; H. Bridge; I. Fine
• Keywords: Splenium

Purpose: The visual cortex in each hemisphere is linked to the opposite by axonal projections that pass through splenium of corpus callosum. Recent human studies (Levin et al., 2010; Lepore al. 2010) find early postnatal blindness leads reductions white matter volume; however it not apparent whether these results reflect myelination and/or disorganization splenial fibers. Here, using diffusion tractography, we examined retinotopic organization connections within 6 anophthalmic and control subjects. In anophthalmia, development eye either absent or arrested at an prenatal stage, no functioning can be detected socket. Methods: Probabilistic tractography was performed on diffusion-weighted MR data (60 directions). Specifically, tracked probabilistic fibers from seed points anatomically defined subregions correspond visually normal individuals three eccentricity bands upper vs. lower field representations (V1/V2). Each point then labeled according its connection probability V1/V2 hemisphere. This method has previously been shown reliably identify callosum (Saenz Fine, 2010). Results: We found mapping measurably disrupted subjects compared controls. These suggest retinal activity experience play little role callosal splenium. Meeting abstract presented VSS 2012