Olivo-vestibular and cerebello-vestibular connections in albino rabbits.
This study analyzes the organization of olivo-vestibular and cerebello-vestibular projections in rabbits. Iontophoretic injections of horseradish peroxidase, placed under physiological guidance into the superior, medial and lateral vestibular nuclei, produced retrogradely labeled neurons in the dorsal cap, ventrolateral outgrowth and lateral flexure of the principal olivary nucleus, the caudal half of the medial accessory olive and the caudal three-fourths of the dorsal accessory olive. This inferior olivary labeling was strictly contralateral. The same injections labeled groups of Purkinje cells in the ipsilateral cerebellar cortex, oriented perpendicular to the long axes of the folia of lobules I-V, VId-e and VIII-X of the vermis and the flocculus. The patterns of olivo-vestibular and cerebello-vestibular connections were consistent with the general hypothesis that inferior olivary axon collaterals project to both Purkinje cells and subcortical neurons inhibited by those Purkinje cells. In addition, the analysis of flocculo-nodular and dorsal cap-ventrolateral outgrowth projections to the medial and superior vestibular nuclei suggests that these connections are discrete at the level of a pool of olivary neurons which projects to functional pools of neurons in both cerebellar cortex, and in the vestibular nuclei. Thus, it is likely that inferior olivary projections define functional networks spanning cerebellar cortex and the vestibular nuclei.
D000818:Animals; D001931:Brain Mapping / Q000295:instrumentation / Q000379:methods; D002531:Cerebellum / Q000502:physiology*; D006735:Horseradish Peroxidase; D009434:Neural Pathways / Q000502:physiology; D009847:Olivary Nucleus / Q000502:physiology*; D011817:Rabbits; D009435:Synaptic Transmission; D014726:Vestibular Nuclei / Q000502:physiology*
D006735:Horseradish Peroxidase