All moral rights asserted. Recolouring or alteration of the image is prohibited without permission. Differential interference contrast light micrograph of trigeminal ganglion neurons (dark) grown in 3 day primary culture conditions. The trigeminal nerve, or fifth cranial nerve supplies the face. Also seen are Schwann cells (bright), which secrete myelin, a fatty substance that insulates nerve fibres. Magnification: x400 when printed at 15 centimetres wide.