Cerebellar nuclei: the olivary connection.

This chapter gives an overview of the relation between the inferior olive and the cerebellar nuclei based on tracing and electrophysiological experiments in rats and cats. The olivary and cerebellar nuclear masses appear to maintain a precise topographical relationship. The olivary projection to the cerebellar nuclei is strictly contralateral, originates as climbing fiber collaterals, and is excitatory. The cerebellar projection to the inferior olive is exactly reciprocal to the olivonuclear projection, but, in addition, also has a variable but definite ipsilateral component, and has been demonstrated to be GABAergic. Stimulation and lesion experiments carried out in cat imply that the cerebellar nucleo-olivary pathway may be involved in regulating the oscillatory capabilities of olivary cells and as such may also have an effect on the synchrony of olivary firing. Subsequent stimulation experiments performed in rats suggests that synchronous firing of olivary neurons may result in profound effects in cerebellar nuclear neurons.