The Brain That Changes Itself: Stories of Personal Triumph from the Frontiers of Brain Science

by Norman Doidge

We now know, from brain scans, that three parts of the brain are involved in obsessions. We detect mistakes with our orbital frontal cortex, part of the frontal lobe, on the underside of the brain, just behind our eyes. Scans show that the more obsessive a person is, the more activated the orbital frontal cortex is. Once the orbital frontal cortex has fired the “mistake feeling” it sends a signal to the cingulate gyrus, located in the deepest part of the cortex. The cingulate triggers the dreadful anxiety that something bad is going to happen unless we correct the mistake and sends signals to both the gut and the heart, causing the physical sensations we associate with dread. The “automatic gearshift,” the caudate nucleus, sits deep in the center of the brain and allows our thoughts to flow from one to the next unless, as happens in OCD, the caudate becomes extremely “sticky.”