For centuries, the out-of-body experience, in which consciousness seems to float away from the body, has been widely regarded as a spiritual or mystical phenomenon. Some parapsychologists still believe that such experiences are just what they seem to be: a separation of consciousness from the body.
Recent research, however, has produced evidence that out-of-body experiences and a related phenomenon, the near-death experience, are produced by abnormal brain activity.
At every moment, the brain effortlessly integrates information from the body into a strong, seamless sense of self. The proprioceptive system, for example, sends signals to the brain that allow you to know, without looking, where your hands, legs and feet are. The vestibular system in the inner ear relays information about your orientation to gravity. (Are you vertical, horizontal, or somewhere in-between?)
The brain’s synthesis of this and other information creates a sense of being inside your body. The out-of-body experience, in contrast, produces a sensation of consciousness floating upward, providing a view of the body from an elevated perspective. It results from a breakdown of the brain’s ability to synthesize signals from the body.
Although out-of-body experiences are reported most often in people with epilepsy and migraine, they also occur in about 10 percent of the healthy population and have been reported in cultures around the world, suggesting that they are rooted in brain physiology. They are difficult to study, however, because they seldom occur more than once in a lifetime.
Close study of out-of-body experiences has led Olaf Blanke, a neurologist at University Hospital in Geneva and a researcher at the Brain-Mind Institute in Lausanne, to believe that this breakdown occurs in the temporoparietal junction (TPJ). This region processes signals that contribute to the sense of balance. Disruption of these signals can induce a sense of floating or falling.
The TPJ also integrates tactile, proprioceptive, and visual information and contributes to the recognition of the human body and body parts.
Blanke inadvertently disrupted some of these signals while preparing a female patient for epilepsy surgery. When he applied electrical stimulation to her right angular gyrus, located behind the TPJ, she experienced distinct out-of-body sensations.
“I see myself lying in bed, from above, but I only see my legs and lower trunk,” she said, according to Blanke.
Stimulating her right angular gyrus may have disrupted signals that are crucial to “own-body perception,” Blanke suggested when he reported on this phenomenon in the journal Nature in 2002 and in the journal Brainin 2004.
This occurrence suggests that the brain constructs awareness of the body, which means that the out-of-body experience “is a good starting point for looking at consciousness, particularly self-consciousness,” Blanke says. “It is not so much, what am I conscious of—for example, holding the phone to my ear. It’s more, who is this person talking? Who is the ‘I’ that is the subject of my consciousness?”
The near-death experience also involves a disruption of the sense of body integration, says Kevin Nelson, a neurologist at the University of Kentucky, but this disruption has a different cause. It involves rapid-eye-movement (REM) sleep intruding into waking consciousness.
During REM sleep the visual and auditory systems of the brain become active, contributing to vivid dreams. In addition, although the eyes move rapidly in their sockets, the major muscles are paralyzed.
Nelson believes that during a near-death experience, these qualities of the REM state intrude into consciousness, producing a sense of being dead or paralyzed, as well as strong visual and auditory hallucinations.
Although the near-death experience may seem distinct from out-of-body experiences, Nelson sees strong links between the two.
“We’re finding out-of-body experiences in normal people during the transition between wakefulness and sleep,” Nelson says. “They tie in with the arousal system, which involves the fight-or-flight system.
Awareness of your body in space is fundamentally important in the fight-or-flight response. I think that’s why people have out-of-body experiences during a near-death experience.”
Nelson says Blanke’s research strongly complements his own because the arousal system originating in the brain stem is somehow linked to the temporoparietal junction.
“The arousal system is connected with the limbic system,” Nelson says. “You experience this when you get angry and your heart beats faster.”
Although recent research undercuts the notion that consciousness can exist apart from the body, it also demonstrates that consciousness is a tenuous creation of the brain. As Blanke says, out-of-body experiences “show that the perception of our own body and self are prone to illusion.”