Migraines and Other Headaches

Scientists believe that migraine headaches have strong genetic roots. At least 70 percent of those with migraine headaches have a close relative (usually a parent or grandparent) who also has migraines.

Although no one knows the exact mechanism, it appears that those who get migraines have a mild instability of the nervous system and blood vessels. During a migraine attack, a “spreading depression” of tiny electrical currents travels from the back to the front of the brain. This current can cause the blood vessels in the brain to tighten and deliver less blood. The migraine sufferer may experience an aura, blurry vision, or dizziness from this partial blood shutdown. When the blood vessels rebound, they dilate, or swell up. This may cause them to leak a small amount of pain-causing chemicals into the skin of the scalp.

The structures in the head that can hurt are the nerves, the blood vessels, and the covering of the brain, not the brain itself. A large nerve (the fifth, or trigeminal, nerve) on the underside of the brain senses chemical and blood vessel changes. At the same time, serotonin, a neurotransmitter that carries messages from nerve to nerve, is also involved in the transmission of pain. A lack of serotonin can make the blood vessels swell or become larger, causing the throbbing pain of a migraine.