The cerebellum is located caudal to the cerebral hemispheres and is connected to the rest of the brain by way of three "peduncles", that convey its afferent and efferent information. The cerebellum is functionally related to spinal, bulbar and cerebral motor systems. Its role in the correct and harmonious execution of movements was already suggested early in the 19th century (Flourens, 1823; Hammond, 1869; Magendie, 1824; Rolando, 1809), and was substantiated in the first decades of the 20th century (Babinski, 1902; Holmes and Stewart, 1904). A schematic representation of the cere bello-cerebral relationships is depicted in Fig. 1.1.