Anatomy of the cerebellum a narrow midline zone called the "vermis". A set of large folds are conventionally used to divide the overall structure into ten smaller lobules. Because of its large number of tiny granule cells, the cerebellum contains more neurons than the rest of the brain put together, but it only takes up 10% of total brain volume. The cerebellum receives nearly 200 million input fibers; in contrast, the optic nerve is composed of a mere one million fibers. The unusual surface appearance of the cerebellum conceals the fact that the bulk of the structure is made up of a very tightly
Cerebellum AICA supplies the front part of the undersurface of the cerebellum. The PICA arrives at the undersurface, where it divides into a medial branch and a lateral branch. The medial branch continues backward to the cerebellar notch between the two hemispheres of the cerebellum; while the lateral branch supplies the under surface of the cerebellum, as far as its lateral border, where it anastomoses with the AICA and the SCA. Damage to the cerebellum often causes motor-related symptoms, the details of which depend on the part of the cerebellum involved and how it is damaged. Damage to the flocculonodular lobe