The Brain's Way of Healing: Remarkable Discoveries and Recoveries from the Frontiers of Neuroplasticity

by Norman Doidge

In vagus nerve stimulation (VNS), an electrode is coiled around the left vagus nerve (a cranial nerve near the carotid artery in the neck), which sends stimulation to the brain stem’s nucleus tractus solitarius, one of the areas targeted by the device. At times VNS works for depression, but it requires surgery to implant a pacemaker into the chest to fire electrical stimulation. Another kind, deep brain stimulation (DBS), has been used on patients with Parkinson’s disease or depression, to target the circuits involved directly, with some success. But with DBS, a surgeon must implant electrodes deep in the brain. The PoNS is matter-of-factly held in the mouth as a child might hold a lollipop.