Albinism Research Today is a free monthly online journal that collates and summarizes the latest research about Albinism, including details on pigmentation, genetic trait, heritability.

The fovea regulates symmetrical development of the visual cortex.

Neveu MM, von dem Hagen E, Morland AB, Jeffery G

Institute of Ophthalmology, University College London, London, United Kingdom.

The foveal region contains the highest cell density in the human retina; consequently a disproportionately large area of the visual cortex is dedicated to its representation. In aniridia and albinism the fovea does not develop, and the corresponding cortical representation shows a reduction in gray matter volume. In albinos there are chiasmatic irregularities in the hemispheric projections, which are not found in aniridics. Here, we ask whether the anomalies in central retinal development, present in albinism and aniridia, have a wider impact on the architecture of the visual cortex. The length, depth, and topology of the calcarine fissure is analyzed in albino, aniridic, and normal subjects. These measures are compared between groups and between the cortical hemispheres within each subject. We show that the calcarine fissure, where the primary visual cortex is represented, is abnormally short in those lacking a fovea. Moreover, surface reconstructions of the calcarine fissure revealed marked interhemispheric asymmetries. The two groups could not be distinguished on the basis of their cortical features, and we therefore interpret the abnormalities in cortical architecture in terms of the absence of the fovea, the common retinal feature found in both groups.

Published 18 December 2007 in J Comp Neurol, 506(5): 791-800.
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