Influences of cerebral cortex and cerebellum on the red nucleus of the rat.

The aim of the present work was to investigate the unitary responses of neurons belonging to the magnocellular and parvocellular division of the red nucleus (RN) to stimulation of efferents from motor cortex and cerebellum. In anesthetized rats spontaneous discharges of rubro-olivary (RO) and rubrospinal (RS) neurons were tested for stimulation of motor cortex (CX), pyramidal tract (PT), interpositus (IN) and dentate (DN) cerebellar nuclei. It has been observed that the majority of RO and RS neurons were influenced by stimulation of both IN and DN as well as by activation of CX and PT. These results indicate that (1) a segregation of cerebral and cerebellar afferents to RN of rat does not exist and (2) convergent responses from the same cerebral and cerebellar structures have been observed in a high number of both RS and RO neurons.