A complex network of brain connections necessary for language comprehension has been mapped in new detail, according to recent research. These newly charted pathways will help scientists understand how language is processed in the brain, and how brain injuries disrupt the system.
The research was presented at Neuroscience 2010, the annual meeting of the Society for Neuroscience, held in San Diego.
"The question of how the brain understands language has puzzled scientists for generations," said senior author Nina Dronkers, PhD, of the Veterans Affairs Northern California Health Care System and the University of California, Davis. "We found rich connections throughout the brain that have not traditionally been associated with language, but are now found to tie together key areas important for understanding language."
Language and speech disorders affect millions of Americans and include a variety of problems, in both spoken language and in reading. In this study, Dronkers and co-author And Turken, PhD, used structural and functional brain imaging techniques on healthy and injured brains to compose a more complete picture of language processes.
Sixty-four people with problems understanding language due to brain injury were scanned with magnetic resonance imaging. The structural images were used to build a digital atlas of the brain regions thought to be associated with their disorders. The researchers then merged this information with new brain scans of 25 healthy volunteers to illustrate the pathways between brain areas. Finally, functional images of another 25 healthy individuals showed the connections between brain regions actually used for language.
"The results revealed a far more extensive network for language functions than current models would predict," Dronkers said. The network included a core region within the left mid-temporal lobe of the brain, and extended to the frontal and parietal cortex in both halves of the brain -- all connected by long distance communication pathways. The next step for scientists is to explore whether other language abilities, such as talking, reading, and writing, also have such dynamic networks.
Research was supported by the Department of Veteran Affairs' Office of Clinical Sciences Research and Development and the National Institutes of Health.
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