Cerebellar afferents in early postnatal rats: a retrograde fluorescence study

The development of afferent projections to the cerebellum was studied by making small (20 nl) injections of True blue into the cerebella of neonatal rats under general anaesthesia. Neurones in all main precerebellar nuclei were labelled even in rats less than one day old. With the exception of the disappearance of small numbers of ipsilateral olivocerebellar projections, no qualitative differences were seen after injections in animals one or two weeks older.