SYNAPTIC CONNECTIONS OF PURKINJE-CELL AXONS WITH NUCLEOCORTICAL NEURONS IN THE CEREBELLAR MEDIAL NUCLEUS OF THE RAT

The cerebellar nucleocortical neurones may be part of a cortico-nucleo cortical loop. It has not yet been demonstrated, however, whether they are directly afferented by Purkinje cell axons. This question has bee n addressed by using electron microscopic methods. WGA-HRP injections into the cerebellar vermis anterogradely labelled Purkinje cell termin als and retrogradely labelled nucleocortical neurones of the nucleus m edialis. Postembedding GABA immunolabelling was used to double-labelle d PC terminals and identified the GABA-immunoreactive nuclear neurones . Of the identified nucleocortical neurones, the majority were immunon egative, but a few were GABA-immunoreactive. Both types were in synapt ic contact with identified Purkinje cell terminals. Copyright (C) 1996 Elsevier Science Ireland Ltd