Out of body? Nope, inside the mind!

A recent New York Times article reported on two papers published in Nature and in Brain magazines by a group of researchers at the Ecole Polytechnique in Lusanne (Switzerland), guided by neurologist Olaf Blanke. This is good stuff, that should take care of the whole paranormal mumbo-jumbo about out of body experiences (but of course it won't, just like modern astronomy hasn't gotten ridden of astrological mythology).

Blanke and colleagues have shown that small electrical currents in certain areas of the brain involved with multi-sensorial perception, such as the angular gyrus, cause the distinct sensation of out-of-body experience or of a strange presence in the room. One patient had the feeling of hanging from the ceiling, another was sure that there was a presence behind her, and a third one felt a “shadow” next to her, attempting to interfere with her activities. These experiences are repeatable under laboratory conditions, which means that a hallmark of parapsychology – out of body experiences – can actually be turned on or off at will by the experimenter, has been traced to perturbations of specific circuits in the brain, and of course has absolutely nothing supernatural about it.

The explanation for this class of neurological phenomena is similar to that of the so-called “phantom limbs,” truly bizarre experiences that were once relegated to purely psychological phenomena but are now understood as a byproduct of the normal functioning of the brain. In the case of phantom limbs people who have lost, say, a leg or an arm keep complaining of itches, or even pain, emanating from where the limb used to be. Until a few years ago these patients were thought to suffer from psychological damage at the shock of losing a part of their body and to react with, essentially, wishful thinking that the part were back into place. It turns out that the severed nerve endings keep sending signals to the brain, which attempts to make sense of them while re-wiring the sensorial circuits. It is this disconnect between the wiring of the nervous system and the mental map of one's body that generates the weird sensation of a phantom limb. The feeling, incidentally, often disappears months or years after the injury, once the brain has had time to rewire its sensorial circuits and properly adjust to expectations concerning the spatial extent of the body.

The phenomena studied under controlled conditions by the Swiss group occur in normal people as well, as a result of a variety of factors including extended sensorial deprivation (during open water sailing, or high elevation trekking), strokes or other disruptions of blood flow to the brain, and, possibly, in pathological conditions such as schizophrenia.

Well, now we have a nice scientific explanation of a range of formerly paranormal phenomena. The explanation is consistent with what we know of human neurobiology and psychology, it is testable and repeatable under laboratory conditions, and accounts also for non-paranormal phenomena such as phantom limbs. Case closed, right? Yeah, right...