Anatomy of the cerebellum and the role played in normal cerebellar function). From the phylogenetically oldest to the newest, the three parts are: Much of what is understood about the functions of the cerebellum stems from careful documentation of the effects of focal lesions in human patients who have suffered from injury or disease or through animal lesion research. As explained in more detail in the Function section, the cerebellum differs from most other brain areas in that the flow of neural signals through it is almost entirely unidirectional: there are virtually no backward connections between its neuronal elements. Thus the most logical way
Anatomy of the cerebellum tree-like appearance—are four deep cerebellar nuclei. The cerebellum can be divided according to three different criteria: gross anatomical, phylogenetical, and functional. On gross inspection, three lobes can be distinguished in the cerebellum: the flocculonodular lobe, the anterior lobe (rostral to the "primary fissure"), and the posterior lobe (dorsal to the "primary fissure"). The latter two can be further divided in a midline cerebellar vermis and lateral cerebellar hemispheres. The cerebellum can also be divided in three parts based on both phylogenetic criteria (the evolutionary age of each part) and on functional criteria (the incoming and outgoing connections each part has