An autoradiographic study of regional differences in DNA synthesis in the brains of young adult mice.

An autoradiographic study of DNA synthesis has shown that repeated injections of 3HTdR result in marked regional differences in labelling of non-neuronal cells in the brains of young adult mice. The incidence of labelled cells was highest in the rudimentary subependymal layer. In the white matter of the corpus callosum and hippocampal commissure, the incidence of LC was several times higher than in the grey matter. Substantial difference was found in the number of labelled cells in the granular population of the olfactory bulb and the dentate gyrus of the hippocampus on the one hand, and the cerebellum on the other. Higher LI values in regions closely associated to rudimentary subependymal layer provide indirect evidence of a selective migration of dividing subependymal cells into neighbouring "target" structures.