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Published October 1, 2010 | public
Journal Article

Topographic organization of V1 projections through the corpus callosum in humans

Abstract

The visual cortex in each hemisphere is linked to the opposite hemisphere by axonal projections that pass through the splenium of the corpus callosum. Visual–callosal connections in humans and macaques are found along the V1/V2 border where the vertical meridian is represented. Here we identify the topography of V1 vertical midline projections through the splenium within six human subjects with normal vision using diffusion-weighted MR imaging and probabilistic diffusion tractography. Tractography seed points within the splenium were classified according to their estimated connectivity profiles to topographic subregions of V1, as defined by functional retinotopic mapping. First, we report a ventral–dorsal mapping within the splenium with fibers from ventral V1 (representing the upper visual field) projecting to the inferior-anterior corner of the splenium and fibers from dorsal V1 (representing the lower visual field) projecting to the superior–posterior end. Second, we also report an eccentricity gradient of projections from foveal-to-peripheral V1 subregions running in the anterior–superior to posterior–inferior direction, orthogonal to the dorsal–ventral mapping. These results confirm and add to a previous diffusion MRI study (Dougherty et al., 2005) which identified a dorsal/ventral mapping of human splenial fibers. These findings yield a more detailed view of the structural organization of the splenium than previously reported and offer new opportunities to study structural plasticity in the visual system.

Additional Information

© 2010 Elsevier. Received 11 February 2010; revised 19 May 2010; accepted 21 May 2010. Available online 27 May 2010. This work was supported by the NEI (61-4892), Dana Innovations in Neuroimaging and The Mathers Foundation. We thank Christof Koch for comments on the manuscript.

Additional details

Created:
August 19, 2023
Modified:
October 20, 2023