This impression of a mimicking, shadowy self-simulation can occur without electrical stimulation to the brain, Dr. Brugger said. It has been described by people who undergo sensory deprivation, as in mountaineers trekking at high altitude or sailors crossing the ocean alone. It is also experienced by people who have suffered minor strokes or Other disruptions in blood flow to the brain.
Six years ago, another of Dr. Blanke's patients underwent brain stimulation to the angular gyrus. The patient experienced a complete out-of-body experience.
When the current flowed, she said: "l am at the ceiling. I am looking down at my legs." When the current ceased, she said: "I'm back on the table now. What happened?"
Because the woman's felt position in space and her actual position in space did not match, her mind searched for the best way to turn her confusion into a coherent experience, Dr. Blanke said. She concluded that she must be floating up and away while looking downward.
Some schizophrenics4, Dr. Blanke said, experience paranoid They delusions5 and the sense that someone is following them. also sometimes confuse their own actions with the actions Of other people. While the cause of these symptoms iS not known, he said, multisensory processing areas may be involved.
When otherwise normal people experience bodily delusions, Dr. Blanke said, they are often completely confused. The felt sensation of the body is so real, so familiar, that people do not realize it is a creation of the brain.
Yet the sense of body integrity is rather easily tricked, Dr. Blanke said. While it may be tempting to credit the supernatural when this body sense goes wrong, the true explanation is a very natural one. It is the brain's attempt to make sense of conflicting information.
1 eerie: strange and frightening
4schizophrenics: people with schizophrenia, a mental disorder in which people confuse reality and imagination 5paranoid delusions: a mental condition that causes one to feel extreme jealously or a false belief that one is being harassed or is an extremely important person in the world