For the first time, scientists at Carnegie Mellon University’s Center for Cognitive Brain Imaging have used a combination of neural imaging methods to discover exactly how the human brain adapts to injury. The research, published in January 2013 issue of Cerebral Cortex, shows that when one brain area loses functionality, a “back-up” team of secondary brain areas immediately activates, replacing not only the unavailable area but also its confederates. The researchers used 16 healthy adult volunteers. They had each one engage in comprehending a sentence inside a machine using fMRI to scan their brain activity. The scanning continued before, during, and after the researchers used a TMS machine to send a pulse of magnetic energy into the precise area of the volunteers’ brains (the Wernicke’s area in the left temporal lobe) which is directly involved in language comprehension. What they found was that although Wernicke’s area was temporarily immobilized, three other back-up areas of the brain immediately activated and coordinated to assist the volunteer in comprehending the sentence. These areas were the frontal lobes (the area of executive function), the contra-lateral area on the right side of the brain that mirrors the Wernicke’s area but has different functions, and the brain areas next to Wernicke’s area.
This experiment served as a very rapid snapshot of what may take place over a much longer time in the brain of a person who suffered a TBI or stroke. In the case of a TBI or stroke victim there is usually a period of global brain impairment with gradual resumption of normal functioning except those functions related to the specific area(s) where the greatest damage occurred. The study shows that brain activities occur not in single areas but in groups and that back-up groups of unharmed cells can be recruited to take over for damaged cells.
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