The find could lead to new therapies for some conditions

Nov 10, 2009 19:31 GMT  ·  By

Words and gesture may seem to be two distinct sets of communication tools, and someone would expect that they are processed in different parts of the brain. However, this does not seem to be the case, as indicated by a new scientific study funded by the National Institute on Deafness and Other Communication Disorders (NIDCD), a division of the US National Institutes of Health (NIH). Details of the investigation are published in the early online issue of the journal Proceedings of the National Academy of Sciences (PNAS), PhysOrg reports.

Scientists have known for quite some time that spoken and written words are deciphered and processed in the same brain areas, but they had no idea that wordless gestures were integrated by the same areas. The new find is highly important, because it seems to indicate the fact that these specific portions of the cortex are the areas from which language originated. If this turns out to be true, then a number of new therapies for conditions related to misunderstanding, or incorrect processing, of words, gestures and other non-verbal clues may be developed.

“In babies, the ability to communicate through gestures precedes spoken language, and you can predict a child's language skills based on the repertoire of his or her gestures during those early months. These findings not only provide compelling evidence regarding where language may have come from, they help explain the interplay that exists between language and gesture as children develop their language skills,” NIDCD director, James F. Battey, Jr., M.D., PhD, says. Previous studies have identified that the two main areas involved in speech processing are the inferior frontal gyrus (Broca's area) and the posterior temporal region (Wernicke's area).

“If gesture and language were not processed by the same system, you'd have spoken language activating the inferior frontal and posterior temporal areas, and gestures activating other parts of the brain. But in fact we found virtual overlap,” adds the senior author of the PNAS paper, Allen Braun, M.D.

“Our results fit a longstanding theory which says that the common ancestor of humans and apes communicated through meaningful gestures and, over time, the brain regions that processed gestures became adapted for using words. If the theory is correct, our language areas may actually be the remnant of this ancient communication system, one that continues to process gesture as well as language in the human brain,” he adds.