In the May 2010 issue of Neurological Sciences there is an interesting article entitled "Is Migraine A Disease?" by Cortelli, Pierangeli, and Montagna. This article theorizes that migraines themselves are normal functions of the body to what the primitive brains of our ancestors saw as threats. When these threats (or triggers) are experienced a cascade of chemical and neurological changes occur as the body attempts to negate the effects of the threat.
One area directly stimulated by these responses is the hypothalamic region of the brain, which is closely related to the "Fight or flight" response. In sensitive individuals if the threats/triggers are detected too frequently, the body starts to anticipate the threat, increasing the reaction and shortening the response time. After many repetitions the condition becomes chronic, resulting in migraine as a malfunction, rather than migraine as a defense mechanism.
Cortelli, et.al., make the point that many of the common triggers for migraine (hunger, lack of sleep or too much sleep, alcohol consumption, light, noise, smell, and stress p. s30) could be seen as threats to brain function. The brain desires to mitigate these threats, and when overwhelmed creates what Cortelli, et. al., describe as excessive allostatic load. Allostasis is the body's active response to restore and maintain homeostasis (normal levels of stress hormones and energy), and allostatic overload results in continued heightened response to stimulus, often in excess to the threat offered.
"Four types of allostatic states leading to allostatic load have been identifiedThe theory put forth is that migraine pain, nausea, photophobia, phonophobia, and sensitivity to odors is a normal defense mechanism of the brain. The abnormal behavior in the migraineur's brain happens when allostatic load is increased frequently and the brain becomes habituated to it and starts to "short circuit". Perhaps that is why many migraineurs find solace in a dark quiet room, lying very still - all threats are minimized and the overactive circuits are able to stop firing.
(1) repeated challenges,
(2) failure to habituate with repeated challenges,
(3) failure to shut off the response after the challenge is past, and
(4) failure to mount an adequate response." (p. s30)
The authors speculate that "Migraine attack may not be considered a disease itself but in presence of a failure of the mechanisms controlling an excessive allostatic load, the repeating of migraine attacks may lead to a morbid state (chronic migraine)." Cortellis, et. al state that the migraine spectrum is a syndrome not a disease or dysfunction, and that more research needs to be done to find the exact mechanism that turns the primitive midbrain response into a chronic pain condition. (p. s30- s31).
In a post I did entitled "Does Anyone Really Know What Causes Migraines?" I wrote "I wonder if what we call "migraine" is actually a catch all for several disparate diseases which all cause similar symptoms by different mechanisms. Perhaps that is why it is so difficult to manage, because there is no real "it"...rather migraine is a loose definition of a entire spectrum of disorders." I guess I could modify this thought with this caveat "or a syndrome with varying causes masquerading as a disease".
My headache disorder, hemicrania continua, is mediated by the hypothalamus. Perhaps my primitive midbrain/hindbrain is in constant alarm state, not able to turn itself off - that could explain the bone weary fatigue that goes with it. I think I must have hit myself in the head too many times in past lives with a rock and am paying the penalty now. Guess my primitive bonehead needs more space for the brain! After all this scientific hoohah babble I have been writing, I think perhaps what brain I have is shriveled up like a raisin.