Granule nerve cell. Coloured scanning electron micrograph (SEM) of a granule nerve cell from the cerebellum of the brain. This nerve cell (neurone) is found in large numbers in the granular layer of the grey matter, the outer layer (cortex) of the cerebellum. Its spherical nucleus (centre right) and several of its thread-like processes are seen here. The grey matter is the site of coordination between the neurones of the nervous system. The cerebellum regulates muscle activity and the maintenance of muscle tone and balance. Magnification: x3500 at 6x7cm size.