Transcendental medicine

American football is often described as a game of inches. Neuroscience is much the same. Forward progress is difficult, and each stride small. And though the basic anatomy of the brain is known, it is not always clear what role each little part plays. Now neuroscientists think they may have pinned down the source of out-of-body experiences, phenomena that have long confounded scientists and delighted occultists.

While probing the brain of a woman who suffered from epilepsy, Olaf Blanke, at the University Hospital of Geneva, found that stimulating the right angular gyrus (a point about an inch above and slightly behind the right ear, and just inside the skull) caused her to feel that she was travelling out of her own body. She also felt herself through dark space, saw her life pass before her eyes and then entered a realm of light where she encountered deceased relatives and friends. She maintained the prevailing emotion during the process was euphoria.

In a treatment undertaken after more than ten years of drug therapy had failed, around 100 electrodes were implanted in the woman’s brain. Over the course of a week, the electrodes were monitored to find the source of electric currents in the brain responsible for the seizures. For around 90 minutes each day, the electrodes were also stimulated to map the structure of the brain so as to identify language centres and other vulnerable areas.

When the current was first applied to the right angular gyrus, the woman reported that she was sinking into the bed, as if falling from a height. As he reports in Nature, a magazine thoroughly devoted to the sciences, Dr. Blanke then systematically applied additional electric currents to the woman’s right angular gyrus. When she looked at her legs during the stimulations, she saw them grow shorter. Similarly, her left arm felt as if it was shrinking. And her head felt much bigger. But when her eyes were averted, the stimulation led to her apparently seeing herself lying in bed, from about two metres above it.

Though he stresses that the mechanisms involved are not fully understood, Dr. Blanke supposes that such an out-of- body experience is caused when inputs from the ‘body schema’ - the system that gives one a sense of one’s own body - get out of synch with those from the vestibular system, which is responsible for balance. But deliberately disrupting this synchronization, Dr. Blanke can induce such experiences.

But this accidental discovery accompanies another pleasing result for Dr. Blanke: after the removal of a small section of her brain identified by the study, the epilepsy patient is now back at work, almost fully cured of her seizures.

(Adaptado de “Transcendental Medicine”, in The Economist, September 21st 2002)

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