Brain stimulation creates shadow person

Olaf Blanke and colleagues at the Federal Polytechnic School of Lausanne say their discovery might help shed light on brain processes that contribute to the symptoms of schizophrenia, which can include the sensation that one's own actions are being performed by someone else.

Doctors evaluating a woman with no history of psychiatric problems found stimulation of an area of her brain called the left temporoparietal junction caused her to believe a person was standing behind her.

The patient reported that "person" adopted the same bodily positions as her, although she didn't recognize the effect as an illusion. At one point in the investigation, the patient was asked to lean forward and clasp her knees: this led to a sensation that the shadow figure was embracing her, which she described as unpleasant.

The finding could be a step towards understanding psychiatric affects such as feelings of paranoia, persecution and alien control, say neuroscientists.

The discovery is reported in a Brief Communication in this week's issue of the journal Nature.

Copyright 2006 by United Press International