Magnetoencephalography (MEG). Man undergoing a brain scan with a neuromagnetometer, to measure normal brain electrical activity. Two non-invasive scanners are positioned above and below his head, each white cryostat having two sets of detectors. This scan technique is called magnetoencephalo- graphy (MEG). The neuromagnetometer measures magnetic fields generated from nerve cell activity within the brain. The scanner contains sensitive magnetic field detectors known as SQUIDS (Superconducting Quantum Interference Devices) cooled in liquid helium. MEG enables high-speed nerve cell activity to be detected, to show the brain working in rapid real" time."