The vagus nerve is one of 12 cranial nerves. It extends from the brain stem to the abdomen, via various organs including the heart, esophagus and lungs. Also known as cranial nerve X, the vagus forms part of the involuntary nervous system and commands unconscious body procedures, such as keeping the heart rate constant and controlling food digestion. The vagus, which is the longest of all cranial nerves, became a point of interest among neurologists in the 19th century when they realized they could curb seizures by applying pressure to it via the carotid artery located in the neck. More recent research has revealed that stimulation of the vagus decreases the frequency and severity of epileptic seizures in animals. As a result, in 1997 the FDA approved vagus nerve stimulation as a method to treat refractory partial epilepsy in patients aged 12 and over. VNS involves implanting a small device in the area of the collarbone and running plastic-covered electrodes under the skin to the vagus on the side of the neck. The device sends electric pulses to the brain during five-minute intervals. This stops electrical disruptions in the brain that are responsible for seizures.
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In Depth: Vagus nerve