Showing posts with label Physics. Show all posts
Showing posts with label Physics. Show all posts

Wednesday, 7 February 2007

Scientists Discover ‘Shadow People’

Ever feel as though you're being followed? As if someone is behind you, shadowing your every move? It might be your 'shadow person', created by unusual activity in a specific brain region, a new study shows.
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The paper, published in the British journal Nature, describes the case of a 22-year-old woman with no history of psychiatric problems who was being evaluated for treatment of epilepsy. When a region of her brain called the left temporoparietal junction was electrically stimulated, the woman described encounters with a 'shadow person' who mimicked her bodily movements.

"Electrical stimulation repeatedly produced a feeling of the presence of another person in her extra-personal space," said Olaf Blanke, co-author of the study conducted by a team of researchers from University Hospital in Geneva, Switzerland.

When the patient was lying down, stimulation of this brain region caused her to feel that someone was behind her. She described the person as young, of indeterminate sex, "a shadow who did not speak or move, and whose position beneath her back was identical to her own", according to the researchers.

When the patient sat up, leaned forward and clasped her knees, she felt that the figure was also sitting, embracing her in its arms - a feeling she described as "unpleasant".

During a language task, in which the seated patient held a card in her right hand, she described the person sitting next to her and trying to interfere with the task. "He wants to take the card … he doesn't want me to read," she said.

Because it was possible to induce the sensation repeatedly, and because the 'shadow person' closely mimicked the patient's posture and movements, the researchers conclude that the patient was experiencing a perception of her own body.

"The strange sensation that somebody is nearby when no one is actually present has been described by psychiatric and neurological patients, as well as by healthy subjects," said Blanke. Until now, however, it was not understood how the illusion was triggered in the brain.

The temporoparietal junction is known to be involved in creating the concept of 'self', and the distinction between 'self' and 'other'. According to the researchers, stimulation of this region interfered with the patient's ability to integrate information about her own body, leading to her experience of a 'shadow person'.

Although the woman was aware of the similarity between her own movements and those of her doppelganger, she didn't recognise the experience as an illusion of her own body.

Similar shadowy encounters have been described by people with schizophrenia, as well as by healthy subjects, leading the researchers to believe that: "Our findings may be a step towards understanding the mechanisms behind psychiatric manifestations such as paranoia, persecution and alien control."

Monday, 5 February 2007

Finding a way to 'see' extra dimensions

Peering backward in time to an instant after the big bang, physicists at the University of Wisconsin-Madison have devised an approach that may help unlock the hidden shapes of alternate dimensions of the universe. A new study demonstrates that the shapes of extra dimensions can be "seen" by deciphering their influence on cosmic energy released by the violent birth of the universe 13 billion years ago. The method, published today (Feb. 2) in Physical Review Letters, provides evidence that physicists can use experimental data to discern the nature of these elusive dimensions - the existence of which is a critical but as yet unproven element of string theory, the leading contender for a unified "theory of everything."Scientists developed string theory, which proposes that everything in the universe is made of tiny, vibrating strings of energy, to encompass the physical principles of all objects from immense galaxies to subatomic particles. Though currently the front-runner to explain the framework of the cosmos, the theory remains, to date, untested.The mathematics of string theory suggests that the world we know is not complete.

In addition to our four familiar dimensions - three-dimensional space and time - string theory predicts the existence of six extra spatial dimensions, "hidden" dimensions curled in tiny geometric shapes at every single point in our universe. Don't worry if you can't picture a 10-dimensional world. Our minds are accustomed to only three spatial dimensions and lack a frame of reference for the other six, says UW-Madison physicist Gary Shiu, who led the new study. Though scientists use computers to visualize what these six-dimensional geometries could look like (see image), no one really knows for sure what shape they take.

View: Full Article | Source: Science Daily