Start of migraine. Image 2 of 3. Thermogram of the head (frontal view) of a patient during the onset of a migraine. The colours show temperatures that range from black (cold) through green (normal) to red, yellow and white (hot). Hot spots (yellow) are seen at the base of the neck, near the eyes, and around the brain (upper right). Migraines are severe, repeating headaches, often accompanied by other symptoms such as nausea and photophobia (dislike of bright light). A migraine starts when blood vessels to the head dilate after a period of constriction. For a thermogram sequence showing the onset of a migraine, see images M210/287-289.