Effect of bilateral enucleation on the development of layers in the dorsal lateral geniculate nucleus

Abstract

Previous results in tree shrew ( Tupaia glis) have demonstrated that retinal afferents in the dorsal lateral geniculate nucleus segregate prenatally and that cell layers segregate postnatally ( Brunso-Bechtold & Casagrande, 1980). In the present study, we examined the effect of bilateral enucleation at birth on the cytoarchitectural differentiation of these cell layers in the tree shrew lateral geniculate nucleus. The enucleated animals were killed at several postnatal ages up to maturity, their brains embedded in celloidin, and sections stained with thionin. The main result was that interlaminar spaces failed to form. Nevertheless, several cellular and cytoarchitectural features characteristic of normal layers were apparent; these included staining intensity, packing density and cell orientation. It can be concluded that the presence of retinal afferents appears necessary for the formation of interlaminar spaces in the lateral geniculate nucleus but not for the differentiation of all characteristics which define the layers.