Neuronal activity in the lateral vestibular nucleus of the cat. V. Topographical distribution of inhibitory effects mediated by the spino-olivocerebellar pathway.

The spatial distribution of inhibitory effects mediated by spinoolivocerebellar pathways and evoked by stimulation of the FRA was studied in Deiters' nucleus by intracellular recordings and extracellular measurements of positive field potentials. At a geven recording site individual nerves greatly varied in their effectiveness: Q and Saph, Tib and FDL were usually the most effective, while GS had very little effect. When comparing several recording sites, various patterns of dominating and nondominating nerves were found, resulting in a somewhat patchy distribution of responses. The results were supported by intracellular recordings, which showed that CF-mediated IPSPs can be evoked from a limited number of nerves only. The findings show that a discriminative pattern exists in the FRA-evoked spino-olivocerebellar-mediated inhibition. In addition, Deiters neurones were found in which the inhibition was evoked from a large number of fore- and hindlimb nerves. Such a generalized inhibitory pattern may be involved in interlimb coordination during locomotion.