The “Science Update” internet article was drawn from a one-page printed article in Nature’s September 19 issue (Blanke, Ortigue, Landis & Seeck, 2002). That article’s four authors, physicians in the Neurology and Neurosurgery programs of Geneva and Lausanne University hospitals in Switzerland, reported findings they’d made during a brain operation to alleviate a patient’s seizures. The 43-year-old woman’s symptoms indicated epilepsy in the right temporal lobe, an area of the brain located above and behind the right ear. Because imaging techniques did not reveal the exact location associated with her seizures, the physicians opened her skull and probed several areas to locate the defective portion, a process known as “brain mapping.” The brain itself does not feel pain, so the patient can be conscious and can speak while physicians probe different locations with minute amounts of electricity. In this way, the patient was able to describe her experience during each electro-stimulation.
[Before continuing with this article, the reader might want to witness this type of brain exploration first-hand by visiting www.pbs.org/wgbh/ aso/tryit/brain and clicking on the phrase “Probe the Brain activity”. There a drawing depicts a patient lying on his/her back, whose skull is open, revealing the brain’s “motor cortex” —the area associated with physical movement. You can probe 17 spots on the motor cortex and see the resulting movement in the patient’s body (arms, legs, mouth, etc). (The site requires Shockwave which, if your computer does not already have it, can be downloaded for free by going to http://sdc.shockwave.com/shockwave/download/frameset.fhtml).]
Like the patient in that drawing, the Swiss woman lay on her back during the operation with her brain exposed just above and behind the right ear. In the process of searching for the site associated with her epilepsy, the physicians stimulated a specific area near the right temporal lobe called the right angular gyrus, and the patient reported intriguing sensations the authors called “out of body experiences.” This brain area was not related to her epilepsy.
When the physicians first stimulated this area, the woman “reported that she was ‘sinking into the bed’ or ‘falling from a height.’” When they increased the electricity, she reported, “I see myself lying in bed, from above, but I only see my legs and lower trunk.” The authors reported that, “two further stimulations induced the same sensation, which included an instantaneous feeling of ‘lightness’ and ‘floating’ about two meters above the bed, close to the ceiling.”
The physicians then asked the patient to “watch her (real) legs during the electrical stimulation…This time, she reported seeing her legs ‘becoming shorter.’” The physicians went on to explain that if her legs were bent at a 90-degree angle before the stimulation, “she reported that her legs appeared to be moving quickly towards her face, and took evasive action.” The authors continued:
“When asked to look at her outstretched arms during the electrical stimulation… the patient felt as though her left arm was shortened; the right arm was unaffected. If both arms were in the same position but bent by 90 degrees at the elbow, she felt that her left lower arm and hand were moving towards her face…When her eyes were shut, she felt that her upper body was moving toward her legs, which were stable.”
The authors asserted that “these observations indicate that OBEs…can be artificially induced by electrical stimulation of the cortex,” and they went on to speculate about the mechanisms involved.