Side of Brain
Important for 'Self-Memory'
NEW YORK (Reuters Health) - Most of the time, the right side
of the brain is better at identifying familiar faces, but when
it comes to recognizing one's own face, the left side of the brain
is tops, new research suggests.
A man who had undergone surgery to treat epilepsy provided Dr.
David J. Turk and colleagues at Dartmouth College in Hanover,
New Hampshire, with an opportunity to evaluate separately the
ability of each side of the brain to recognize familiar faces.
To treat epilepsy that did not respond to other therapies, fibers
in the man's brain that connect the left and right brain hemispheres
had been cut. Therefore, the two brain hemispheres could no longer
communicate with one another, which allowed the researchers to
investigate their individual functions.
Using computer technology, the researchers altered a pair of
photos, one of the patient himself and the other of "Mike," a
doctor the patient knew well. Some of the altered photos looked
more like the patient while others resembled the doctor more.
When shown the photos, the man had to decide whether the picture
looked more like himself or Mike. The same exercise was repeated
with photos of other easily recognized faces, including President
Bush and former President Clinton.
The right hemisphere of his brain did a better job at recognizing
faces, with one exception, according to a report in the advance
online edition of the journal Nature Neuroscience for September.
The left side of the man's brain was more accurate at recognizing
his own face.
"Our results support the view that, although both hemispheres
are capable of self-recognition, cortical networks in the left
hemisphere have an important role in the execution of this process,"
Turk and his colleagues write.
According to the researchers, the brain is thought to possess
a "self-memory system" made up of each person's conception of
himself or herself. The fact that the left hemisphere is better
able to recognize photos of the self suggests that this side of
the brain plays a dominant role in the self-memory system, the
SOURCE: Nature Neuroscience 2002;10.1038/nn907.
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