The vagus nerve is part of the autonomic nervous system, which controls bodily functions that are not under voluntary control, such as the heart rate. The vagus nerve passes through the neck as it travels between the chest and abdomen and the lower part of the brain.
Vagus nerve stimulation (VNS) is one treatment for epilepsy. It uses an implanted device, somewhat similar to a pacemaker, that is designed to prevent seizures by sending regular, mild pulses of electrical energy to the brain via the vagus nerve.
The VNS device is surgically placed under the skin on the chest wall and a wire runs from it to the vagus nerve in the neck.
The neurologist programs the strength and timing of the pulses according to each patient's individual needs. The settings can be updated and maintained without entering the body, using a "programming wand" connected to a computer.