Cerebral nerve cells. Light micrograph of the boundary between grey and white matter in the brain. The grey matter (green, right) contains the bodies of many interlinked nerve cells (green bodies, pale nuclei). This area of the brain is responsible for conscious thought, sensation and controlling movement. The white matter (blue, left) is almost entirely made up of densely packed nerve fibres from the cells of the grey matter. Nerve cells have two main types of process: small, branched dendrites are the cell's sensory input equipment, and nerve fibres ( Iaxons i) are the output processes, and relay signals from the cell body to a target. Magnification unknown.