[Intracellular study of the formation of new synapses and collateral sprouting of red nucleus neurons after destruction of the cerebellar nucleus interpositus in the adult cat].

Responses of red nucleus neurons to stimulation of ipsilateral cerebellar nucleus interpositus were studied in cats after lesion of contralateral cerebellar nucleus interpositus within the period ranging from two weeks to one year and seven weeks. Recording of fast and slow mono- and polysynaptic EPSPs showed collateral sprouting of axons of interposito-rubral neurons to occur in various parts of soma-dendritic membrane of rubro-spinal neurons. Stimulation of ipsilateral cerebellar nucleus interpositus evoked antidromic activation in many red nucleus neurons, suggesting the sprouting of axon collaterals from rubro-spinal neurons onto the neurons of ipsilateral cerebellar n. interpositus projecting to the red nucleus.