Cerebellum structure. Fluorescent light micrograph of a section through the highly-folded cerebellum of the brain. The tissue has been tagged with fluorescent dyes: cell nuclei are red, neurofilaments are blue and glial fibrillary acidic protein (GFAP) is green. Neurofilaments are structural proteins found in the axons (output processes) of neurons (nerve cells). The neurofilaments are concentrated in the inner white matter of the cerebellum. The cell nuclei are most abundant in the granular layer of the grey matter. The outer molecular layer of grey matter contains cell nuclei and glial cells rich in GFAP. Magnification: x40 when printed 10cm wide.