Confocal light micrograph of a section through tissue from the cortex of the brain. Glial-fibrillary acidic protein (GFAP), a type of intermediate filament (IF), part of the cell's cytoskeleton, has been dyed green. Neurofilaments, structural proteins found in the axons (output processes) of neurons (nerve cells), are red. Cell nuclei, which contain the cell's genetic information, are blue. The cortex, or grey matter, is the outer layer of the brain, and is composed mainly of nerve cell nuclei. The cortex is involved in conscious thought, language and awareness. Magnification: x1,100 when printed at 10 centimetres wide.