Migraine. Single Photon Emission Tomography (SPET) image of the brain in a patient during an attack of Classical Migraine. The colour-coded image shows areas of the brain that are metabolically active (red); low activity with reduced blood flow is caused by migraine (at lower left). Classical Migraine describes a recurrent throbbing headache that typically affects one side of the head, associated with nausea and vomiting. It is often preceded by an aura of flickering lights or blurred vision. This image was made in collaboration with the Princess Margaret Migraine Clinic at Charing Cross Hospital, London.