In the mind's eye, an arm or hand changes shape, study finds,,
THURSDAY, June 25 (HealthDay News) -- Pick up a golf club and your brain may do more than look for an easy par three.
New research suggests that the brain considers tools to be extensions of the body.
The mere act of holding a mechanical grasping tool "temporarily modifies the cerebral representation of a subject's arm," said Lucilla Cardinali, a graduate student in France and lead author of the study.
In other words, people think their arm is longer, at least for a moment.
It's not immediately clear what this new knowledge about the "schema" -- people's internal representation of themselves in the world -- could mean in terms of treatment of illness.
But it could potentially help people with conditions that have disrupted their view of their place in space, such as amputees who receive hand transplants, said Cardinali, who studies at Claude Bernard University in Lyon, France.
Scientists have discussed the concept of schema since the 19th century as they've tried to figure out how the brain comprehends where someone is and where that person wants to go.
To move around, people must understand their position in the space around them and also have to anticipate what will happen when they move their bodies or a body part. Usually that's done with ease.
"You know exactly where that toothbrush needs to go to fit your teeth -- as if it's an extension of your arm," said Paul Sanberg, a professor of neurosurgery at the University of South Florida College of Medicine.
Some people with neurological problems have difficulty with that process, however, and tests have shown they can't imagine rotating their hands, Cardinali said.
In the French study, published in the June 23 issue of Current Biology, researchers used measurements to show that people acted as if their arms had extended a
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