Normal vision, strabismus and the corpus callosum in animals

In the primary visual cortex of higher mammals, both the retino-geniculo-cortical (RGC) and the interhemispheric callosal pathways contribute to the unification of the visual hemifields that project separately within the two hemispheres. Anatomical and functional studies performed on animals reveal that each pathway complements each other both spatially and in terms of binocularity. They also reveal that this pattern emerges progressively with age during the critical period, proving however postnatal visual experience has been normal. In case of abnormal postnatal vision such as the one led by strabismus, both pathways develop abnormally. In particular, we have shown recently that asymmetrical callosal connections develop and this prevents the establishment of a unifying representation of the two visual hemifields. As a general rule, we suggest that crossed and uncrossed RGC pathways contribute successively to all this.

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