|The Neurobiology Behind Out-of-Body Experiences|
September 27, 2002|
You are floating several feet above the ground...
You look down...
You are not watching a TV episode of The X-Files or The Outer Limits. Rather, you are experiencing an "out-of-body experience" or an OBE.
OBEs are brief sensations that occur when a person feels as if his mind separates from his body. During OBEs, people sense that they are floating above their own bodies. No one knows what causes OBEs, but some people believe that OBEs are religious or spiritual events. Interestingly, many people who have come close to death report that they have had an OBE.
Researchers from the University Hospitals of Geneva and Lausanne (Switzerland) have found that OBEs can be produced by direct electrical stimulation of a specific part of the brain. Dr. Olaf Blanke and his colleagues worked with a 43-year-old female patient who suffered from right temporal lobe epilepsy. In order to identify the location where the seizures occurred, the researchers implanted electrodes on the brain under the patient's dura. While the patient was awake, the researchers could pass electrical current through the electrodes to identify the function of the brain area under each electrode.
Electrical stimulation of the angular gyrus on the right side of the patient's brain produced unusual sensations. Weak stimulation caused the patient to feel as if she was "sinking into the bed" or "falling from a height." Stronger electrical stimulation caused the patient to have an OBE. For example, the patient said, "I see myself lying in bed, from above, but I only see my legs and lower trunk." Stimulation of the angular gyrus at other times caused the woman to have feelings of "lightness" and of "floating" two meters above the bed.
The angular gyrus is located near the vestibular (balance) area of the cerebral cortex. It is likely that electrical stimulation of the angular gyrus interrupts the ability of the brain to make sense of information related to balance and touch. This interruption may result in OBEs. Blood flow changes within the angular gyrus may alter brain activity during "near death experiences." This may result in OBEs reported by people who survive such events.
| Reference and more
Blanke, O., Ortigue, S., Landis, T. and Seeck, M. Stimulating illusory own-body perceptions. Nature, 419:269-270, 2002.
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