What Migraine Does to Your Brain

I had migraines nearly every day for about 30 years.

While I did have a headache, like most male migraineurs my symptoms were primarily sensory and verbal. I would see stars, like I had been punched in the face. Often I would have a blind spot that would expand across my field of vision, fuzzy lines that weren't total darkness but that didn't make any visual sense. I would feel dizzy and nauseous. And I'd become extremely tongue-tied. "I am having a migraine" might become "Itchy head migraine ouch," or something in another language entirely.

My experience with migraine is anything but unique. More and more researchers are realizing that migraine isn't a painful headache caused by expansion of blood vessels in the head. Migraine is primarily a neurological condition that can compared to a "very slow stroke." If you have migraines nearly every day, as I did for years, they cease to cause anxiety, but if they are an occasional event for you, then the painful headache can also become the prelude to a generalized anxiety attack that can be every bit as disabling as the migraine itself.

Migraine Is a Much More Serious Condition Than Most People Know

Physical evidence for his theory was scarce until 2004, when another neuroscientist named Mark Kruit at from Leiden University Medical Center in the Netherlands and his colleagues gave MRIs to 300 migraine patients and 300 healthy controls. These brain scans revealed that the MRIs of people who have migraines were much more likely to have bright spots in the white matter of the cerebellum. These spots were found in the part of the brain that insulates neurons so that they don't generate "stray sparks" that would interfere with the passage of electrical signals from the back of the brain to the cerebral cortex. And in about 8 percent of the volunteers who had migraines, Kreut and colleagues found evidence of stroke-like damage to the brain. These lesions were more common in migraine sufferers who experience auras, the kaleidoscopic shapes and colors or the zig-zag shading of central vision before headache pain starts.

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Stroke-Like Damage

The main reason that neuroscientists refer to brain damage in migraine as "stroke like" is that it is known that blood circulation to the parts of the brain affected by migraine first increases and then decreases, as it would in a stroke. That's where the similarity to stroke ends. People who have this kind of damage don't develop paralysis or loss of speech as they might in stroke. They don't signal future development of Alzheimer's or dementia. The number of spots tends to increase over time in women who have migraines, but not in men. However, stroke-like lesions are not the only brain changes that occur with chronic migraine.

How Migraine Changes Your Brain

Numerous researchers have found that repeated migraine attacks results in thickening of certain areas of the brain, especially those that process visual information and pain, especially pain in the head and face. The more headaches you have, the thicker the part of the brain that makes you aware of headache pain becomes — and the more intensely you feel pain the next time you have a migraine attack. When people have frequent headache pain, they often develop a condition called allodynia, in which even normal touch is painful. This happens to about one-fourth of people who have chronic migraine. 

Similarly, the more visual disturbance you experience during a migraine headache, the thicker your visual cortex grows, and the visual disturbance you experience during your next attack is even more severe. In these thicker layers of the brain, electrical disturbances grow more intense, and a spreading depression that acts something like an epileptic seizure can be detected with EEG.

A migraine brain becomes very excitable, much more excitable than a brain that doesn't have migraine. There changes in the cerebral cortex, which facilitates judgment. There are changes in the hippocampus, which enables both the formation of new memories and the creation of autobiography, the understanding of oneself. There are changes in the brain's reward systems, so that control over various kinds of appetites for food, sex, and excitement also are altered. Most concerning to neuroscientists, however, is recent evidence that migraine also changes the hypothalamus.

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The hypothalamus controls internal body states. It regulates sleeping and wakefulness. It regulates appetite, metabolism, and hormone levels. The neural circuits surrounding the hypothalamus cause many of the symptoms of migraine, such as nausea, vomiting, insomnia, sleepiness, watering eyes, nasal congestion, hunger, thirst, yawning, and fatigue. 

The hypothalamus also controls how we respond to cold, hunger, and exercise. When the hypothalamus is super-sensitive to changes in the metabolism, cold, hunger, and exercise become triggers for migraine, and the more often you have migraine, the more intensely these external factors affect it.

Difference in Male and Female Migraine Brains

Migraine causes different brain changes in women and men, especially in the parts of the brain that are associated with emotion. In women, migraine causes a thickening of the precuneus, a part of the brain that answers the question "Who am I?" Many women report that the area of the head that becomes painful first during a migraine is also the area of the head that they feel when they close their eyes and think about what it means "just to be me."

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Female migraine sufferers also have more thickening of the insula, the part of the brain that answers the question "What's important now?" As a result, stress has a greater effect on migraine in women than in men.

Is There Relief Ahead?

This new understanding of migraine has led to some new treatments for migraine. One is transcutaneous magnetic stimulation, also known as TMS, in which pulsating low-gauss magnets are placed in a headband or a probe to be worn when migraine symptoms come on. (A kitchen magnet won't work. The magnetic field has to be pulsating.) The magnetic field interferes with the spreading depression that makes the headache worse.

TMS is a possible treatment for people who experience rebound headaches when they have to cut back on their medication, for women who are pregnant, and for those who have become insensitive to migraine drugs. A TMS device usually costs $500 to $1000, but may be covered by insurance.