In VNS a two-inch diameter, .25 inch thick disk is surgically tucked under the skin near the left collarbone, then wired upward to the vagus nerve in the neck. The battery-operated disk delivers intermittent, rhythmic pulses to the nerve -- whose name means "wandering" in Latin -- that reaches a half dozen areas of the brain critical to treating depression, according to Dr. Darin Dougherty of Massachusetts General Hospital.
The implanted disc is programmed and reprogrammed with a wand held over the skin. Data on each patient about the intensity and frequency of the pulse and device settings is stored in individual memory cards slotted into in a handheld computer linked to the wand.
Researchers know the treatment stimulates norepinephrine and serotonin centers, now treated with pharma at a tepid success rate, and increases blood flow and neuron activity. But they candidly say they don't fully understand why VNS works.
Vagus Nerve Stimulation
Current Music: Killing Joke -- Implant ♬