REPRESENTATION OF THE TONGUE IN THE CEREBELLAR NUCLEI OF THE MONKEY

Electrophysiologic techniques were used to determine the pattern of representation of the tongue within the cerebellar nuclei of the monkey, Macaca mulatta. The cerebellar nuclei were stimulated with bipolar, concentric electrodes, and lingual activity was recorded electromyographically from the extrinsic tongue musculature with indwelling needle electrodes. Correlative gross tongue movements were also monitored via a system of force-displacement transducers. The results indicate that the tongue is represented within each of the four cerebellar nuclei; however, the degree of representation is not equivalent. Whereas numerous stimulus sites in the fastigal and anterior interposed nuclei were effective in influencing tongue muscle activity, effective sites were limited to medial and rostral regions of the dentate nucleus and to a small central region of the posterior interposed nucleus. This particular pattern of tongue representation in the cerebellar nuclei has implications for the anatomicofunctional organization of the cerebellum for controlling other somatic motor organs. © 1979.