Migraine - What Is It?

Patient Expert

Migraine is a genetic neurological disease...

What is a Migraine? That's partly answered by saying what a Migraine is not. A Migraine is not a headache.

Migraine has now been shown to be a genetic neurological disease characterized by flare-ups often called "Migraine attacks." A headache can be one symptom of a Migraine attack, but it's just that -- one of the possible symptoms. Some Migraineurs (people with Migraine disease) have Migraine attacks without having a headache. These are called "acephalgic" or "silent" Migraines.

"Migraine was previously considered to be caused primarily by constriction and dilation of blood vessels in and around the brain. But more recent studies indicate that migraine is caused by fluctuations in brain chemicals and abnormal electrical activity in specific brain regions. Specialized brain scans of patients having migraine attacks show waves of abnormal activity that spread across the surface of the brain (the cortex), as well as excitation of nerve centers deep within the brain (the brainstem). Recent research has focused on treatments that work not by constricting blood vessels, but rather by reducing the patterns of abnormal brain cell activity that are believed to underlie migraine."

There are still multiple theories of what actually occurs to bring on a Migraine attack when we encounter a trigger. Advancements in imaging technology have allowed scientists to actually observe the brain during a Migraine attack. The most prevalent theory is that Migraineurs have overly excitable neurons in our brains. When a trigger is encountered, those neurons fire in a wave across the brain, starting a cascade of event involving several centers of the brain including the brainstem.

The final common pathway involves dilation or swelling accompanied by inflammation of small arteries in the coverings of the brain. The headache of a Migraine attack, if there is one, is from sensory impulses transmitted by the nerves from these inflamed blood vessels and surrounding tissues transmitted to higher centers of the brain and experienced as pain.

There are, within Migraine disease, different forms of Migraine. The most common is Migraine without aura (formerly called common Migraine), followed by Migraine with aura (formerly called classic Migraine). Only about 25% of Migraineurs experience an aura, and even within that 25% it's unusual to experience aura with every Migraine attack. Most commonly, Migraineurs have a diagnosis of Migraine without aura, or Migraine with and without aura.

There you have the condensed answer to, "What is a Migraine?" For more information, please see these articles on various forms of Migraine and headache:

More from our "Basics" series:


Charles, Andrew, MD. "Migraine: Questions and Answers for Patients." February 9, 2012

Medical review by John Claude Krusz, PhD, MD