gammaCore is an external vagus nerve stimulator that is FDA-approved for treating cluster headache and migraine. To explain what makes the gammaCore work, I have to back up a bit to talk about the vagus nerve.
What is the vagus nerve?
The vagus nerve is the body’s longest cranial nerve and has many branches. It connects to numerous organs, including the heart, lungs, and stomach. (The vagus nerve is shown in yellow in the image.) Here’s how electroCore, the company that makes gammaCore, describes the vagus nerve:
It is the longest cranial nerve in the body, primarily serving as a sensory nerve, bringing information from the visceral organs to the brain. The vagus nerve has a number of branching nerves that go to the heart, lungs, voice box, stomach, ears, and other organs. As a sensory nerve that assesses the condition of these organs, it is the communication between the brain and the body. It contains motor and sensory fibers and, because it passes through the neck and thorax to the abdomen, has the widest distribution in the body.
While we don’t hear as much about the vagus nerve as we do the occipital or trigeminal nerves, researchers believe it plays an important role in both migraine and cluster headache. You’ve likely heard of the vagus nerve in connection with it’s most “famous” responsibilities: it plays a central role in the fight-or-flight response and it connects the brain to the stomach, sending signals between the two. (Since eating anything is a migraine trigger for me, this connection is what prompted me to travel to Canada to try the gammaCore.)
How does the gammaCore work?
Like with so many therapies, how the gammaCore works isn’t entirely known. electroCore’s website currently says, “Stimulating the vagus nerve affects many important autonomic functions in the brain and in the body, including neurotransmitter levels, inflammation levels, and metabolism.” In videos published in 2012 and 2014, electroCore explains the role of neurotransmitters and how the gammaCore influences them. Here’s my summary (and you can watch the videos yourself below).
The gammaCore is thought to balance neurotransmitters, which help regulate a person’s nervous system. Neurotransmitters can be classified as excitatory or inhibitory. Excitatory neurotransmitters rev up the nervous system; inhibitory neurotransmitters calm the nervous system. The brain tries to maintain an equilibrium by constantly balancing excitatory and inhibitory neurotransmitters. Scientists believe that people with headache disorders like migraine and cluster headache may have too many excitatory neurotransmitters and not enough inhibitory neurotransmitters. One particular neurotransmitter, glutamate, is particularly suspect. The gammaCore is thought to balance neurotransmitters by stimulating the “nervous system’s superhighway,” as electroCore calls the vagus nerve.
Video Explanations of How the gammaCore Works
These videos from electroCore, the company that makes the gammaCore, give a better explanation than I can. The information in the two videos is basically the same—the first is the layperson’s explanation and the second is more technical. Both videos are worth watching, though I recommend starting with the intro video. (You may be annoyed by the narrators’ liberal use of the word “headache”—it can seem like they minimize the severity of migraine and cluster headache. I give them leeway because they’re trying to encompass both migraine and