UBC Theses and Dissertations
Investigation of striate cortico-geniculate fibres Nagai, Martha
The history of the discovery of the visual cortex is reviewed and previous investigations on the corticofugal fibre connections from the visual cortex to the brain stem area presented. Efferent fibres from the visual striate cortex to the lateral geniculate body of the monkey have been investigated, following striate cortex ablation. Sections at five different points through the lateral geniculate body were stained with Del-Rio-Hortega’s double impregnation method and have been examined for fibre and "bouton terminaux" degeneration. Two other stains, Nauta and Gygax silver stain to further determine degenerating fibres, and Einarson's chrom alum stain to differentiate the structures within the sections, were used for this investigation. Experimental results showed that there was a consistent increase (with an exception of one section) in the number of boutons on the side corresponding to the lesion. This increase is statistically significant. The presence of a substantial volume of degenerating fibres and an abundance of heavily stained, almost solid type of "bouton terminaux" occurring on the side of the lesion has strongly suggested that there are actually a number of corticofugal or efferent fibres from the striate area to the lateral geniculate body.
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