Why is the vagus nerve stimulated?
The vagus nerve is the major information expressway between the brain and most of the internal organs. Researchers are now studying how this stimulant can improve mental and physical health.
Have you felt butterflies in your stomach or hunger pangs? Those “gut feelings” are caused by the vagus nerve, a superhighway that connects the brain and the gut.
In recent years the vagus nerve has become an interesting target for researchers who want to treat disorders of both the brain and the body. Vagus nerve stimulation — usually achieved with an electrode implanted in the neck to deliver electrical waves directly to the nerve in the brain — is an approved treatment for epilepsy and some forms of depression. Scientists are now studying vagus nerve stimulation (VNS) for disorders such as rheumatoid arthritis and the inflammatory bowel disease Crohn’s.
What gives this nerve such a wide range of effects? The vagus nerve is the longest of the cranial nerves, arising directly from the brain rather than passing through the spinal cord. It begins at an opening at the base of the skull and travels down the neck to the stomach, where it collects signals from the gut and helps regulate the body’s automatic processes, from digestion to sleep to inflammation.
About 80 percent of these signals are sensory signals transmitted from internal organs, while the other 20 percent travel through the body and control things like intestinal contractions and heart rate.
The vagus nerve plays an important role in the parasympathetic mesentery, a “relaxation and digestion” system that calms the body during times of low stress. “When you’re resting, when you’re sleeping, when you’re in a state of rest, the vagus nerve dominates,” says psychiatrist Gregor Hassler of the University of Friborg in Switzerland, who has studied the gut-brain connection. written about. Ouch.
Researchers have long encouraged attempts to influence brain function by not implanting electrodes inside the brain, because the vagus nerve produces a direct wave-like signal. The Food and Drug Administration approved VNS in 1997 as an adjunct to the treatment of epilepsy. Soon, says Ziyad Nahas, doctors began noticing that some of their patients with epilepsy had improved moods, regardless of whether or not the treatment helped control their seizures. who practices vagus nerve stimulation and other types of neuromodulation at the University of Minnesota Medical School.
The FDA also approved VNS in 2005 for treatment-resistant depression, following clinical trials in Europe, Canada, and the US. People who experience persistent somnolence and have tried at least four treatments without improvement are eligible for stimulation, which involves implanting both electrodes in the mane and blank energy sources in the collarbone. Surgery is involved. Nahs says that after one year of treatment, VNS patients are twice as likely to be cured of treatment-resistant depression than the general population.
He adds, doctors believe fame is linked to the vagus nerve’s influence on the release of neurotransmitters such as serotonin and norepinephrine, both of which are important for mood. And neural stimulation activates the parts of the prefrontal cortex involved in regulating the limbic regions of the brain that control emotion.
“Nodes that are important in mood regulation appear to execute very specific modulations,” says Nahs.