Immunofluorescent light micrograph of a branching nerve fibre, with astrocyte cells, in mammalian brain cortex. In the foreground, the nerve fibre of a mature neuron (yellow) has the appearance of a lightning bolt. This is the route of transmission of nerve impulses. Behind it are astrocytes (orange): starshaped connective tissue cells providing mechanical support and nutrients for the neurons. It is thought that astrocytes may take part in information storage processes. Immunofluorescence is a staining technique using antibodies to attach fluorescent dyes to specific tissues and molecules within the cell. Magnification x200 at 35mm, x375 at 6x4.5cm.