Excerpts from our conversation with Dr. K.C. Brennan, an expert on migraine and headache treatment at the University of Utah.
NIHNiH: How do you approach treating migraine?
Brennan: Migraine is a disorder of human brain networks. So if you don’t treat the whole person, you’re not going to get the best results.
The nervous system’s “volume knob” is turned up in many different places in migraine. It’s turned up in sensory systems, so light hurts, sound hurts, smells are noxious. Even your gut sensations are amplified. People get nauseous and vomit. This is part of what makes migraine awful. But each one of those things is also something you can target with treatment.
So you can reduce the effects of light on the eyes without using any medication. You can treat the gut as well as the brain. You can treat the muscles that are sore, that trigger a migraine attack, with things like physical therapy, with yoga.
And then when people are in pain, there’s an imbalance in the nervous system. There’s an increase in the volume knob of what we call affective or emotional networks. So if you’re in pain every day of your life, you’re likely to be depressed and anxious. We need to address this wiring in the nervous system for someone to heal.
I prefer the word “heal” rather than “cure.” We don’t have a cure for migraine yet. But healing is getting to a place where it’s no longer an overwhelming part of your life, whatever that means to you. You can still have some pain but feel healed from your disease.
NIHNiH: Some people with migraine experience aura. What and why is that?
Brennan: Migraine aura happens to about a third of people with migraine. For a lot of people, aura is flashing lights in their vision or numbness and tingling that moves along their arm or their face right before a migraine attack. And we actually know what causes that: It’s called spreading depolarization.
You can think of the nervous system as a really complex bunch of wires with little light bulbs at different places that light up and send messages to each other. These are really fast messages moving almost at the speed of light. When the nervous system functions normally, it’s sort of on and off, zigging and zagging.
Spreading depolarization is almost the opposite of that. It’s like a tsunami, a huge wave. The electrical activity is bigger than what happens in a seizure. And that wave moves through that bunch of “wires” and forces every neural cell, every blood vessel cell, every supporting cell to fire off and deplete all its energy.
And then it moves on, and it leaves a large silence in its wake. Instead of the on/off, zigging and zagging of normal nervous system activity, imagine a giant wave of lights going off, spreading like a ripple in a pond, and then going dark.
At the front of this wave is a bunch of activity. So when people see the flashing lights or prisms in their vision with the migraine aura, that’s the wave of activity. But an equally prominent part of the migraine aura, for a lot of people, is after it’s passed, there’s often a loss of sensation.
NIHNiH: What have you learned about migraine aura from your research?
Brennan: It’s been very difficult to explain how such a massive wave of activity could start, apparently spontaneously, in an otherwise healthy brain.
We’ve been looking at glutamate, which is the main excitatory neurotransmitter of the brain. Glutamate is a known actor in any excitable brain disorder, not just migraine but things like epilepsy and pain.
We’ve been using a new glutamate indicator. It’s essentially a dye we can put into the nervous system in mice. We can put the gene that produces it into mice, and you’ll get little fluorescent signals in the brain when glutamate is released.
And what we discovered was that, before the onset of spreading depolarizations, there was a flurry of little plumes or puffs of glutamate. Almost like little popcorn kernels going off, first a few then a bunch together. And these became more frequent and then coalesced and formed the origin point of a spreading depolarization.
And these puffs of glutamate predicted the location and onset of a spreading depolarization. This is the first clue about what might start these mysterious spreading waves in the first place. Now we’ve got to figure out what the mechanism behind the plumes is. And that may help us develop a more tailored approach to migraine prevention.
If you care about pain, please read studies about Chronic morphine use for cancer pain may increase bone loss and findings of Scientists find a new hope for chronic pain.
If you care about pain, please read studies about What you need to know about diabetes and joint pain and findings of Understanding the connection between liver disease and joint pain.
Source: NIH.
