Good New York Times article on neural stimulation and the production of paranormal brain states

They are eerie sensations, more common than one might think: A man describes feeling a shadowy figure standing behind him, then turning around to find no one there. A woman feels herself leaving her body and floating in space, looking down on her corporeal self.

But according to recent work by neuroscientists, they can be induced by delivering mild electric current to specific spots in the brain. In one woman, for example, a zap to a brain region called the angular gyrus resulted in a sensation that she was hanging from the ceiling, looking down at her body. In another woman, electrical current delivered to the angular gyrus produced an uncanny feeling that someone was behind her, intent on interfering with her actions.

The two women were being evaluated for epilepsy surgery at University Hospital in Geneva, where doctors implanted dozens of electrodes into their brains to pinpoint the abnormal tissue causing the seizures and to identify adjacent areas involved in language, hearing or other essential functions that should be avoided in the surgery. As each electrode was activated, stimulating a different patch of brain tissue, the patient was asked to say what she was experiencing.

Dr. Olaf Blanke, a neurologist at the École Polytechnique Fédérale de Lausanne in Switzerland who carried out the procedures, said that the women had normal psychiatric histories and that they were stunned by the bizarre nature of their experiences.