Anatomy of the cerebellum major part of the cerebellum by mass, but in other vertebrates, it is typically the spinocerebellum. In amphibians, lampreys, and hagfish the cerebellum is little developed; in the latter two groups it is barely distinguishable from the brain-stem. Although the spinocerebellum is present in these groups, the primary structures are small paired nuclei corresponding to the vestibulocerebellum. The cerebellum follows the general groups-of-three pattern found in anatomy, with three major input and output cerebellar peduncles (fiber bundles). These are the superior (brachium conjunctivum), middle (brachium pontis), and inferior (restiform and juxtarestiform bodies) cerebellar peduncles. There are three sources of input
Anatomy of the cerebellum cerebellar cortex. Under resting conditions in animal experiments, groups of olivary neurons discharge synchronously at 5 to 10 Hz (impulses/s). In the cerebellar cortex, the response of Purkinje cells takes the form of complex spikes. The cerebellum send its projections back to the cerebral cortex via the Cerebellothalamic tract. The cerebellar lateral expansion, or the neocerebellum, may be associated with cognitive functions, and it is anatomically linked with the lateral prefrontal cortex. It shows greatest activity during speech, with a one-sided predominance consistent with a possible linkage (via the thalamus) with the motor speech area. When lesions occur in the