Migraine. Conceptual artwork of lightning flashes marking the epicentre of pain in a man's forehead. A migraine is a recurrent headache which can be accompanied by nausea, vomiting and sensitivity to light and sound. These symptoms are caused by changes in brain activity which produce inflamed blood vessels (red) and nerves (yellow) around the brain (not seen). The exact cause is unknown, but triggers that provoke an attack include certain foods, stress and anxiety, and too little or too much sleep. In women there may be a link between sex hormones and migraine attacks. Migraines cannot be cured but triggers should be avoided and the symptoms treated.