Greg Hickok, professor of cognitive sciences, will lead a team of scientists from UCI, UC San Diego, the University of Southern California and the University of Iowa in this research that may one day help those with language disorders caused by stroke, Alzheimer's disease and autism. The grant is a renewal from the National Institute on Deafness and Other Communication Disorders (NIDCD), a component of the NIH, and will allow Hickok to continue the work he has done in this field since 1999.
"When we listen to speech, what hits our ears is nothing more than tiny fluctuations in air pressure, or sound waves," Hickok said. "The ability of humans to turn these sound waves into meaningful language is a complex task, one that we have not managed to replicate yet with computer voice recognition systems. This project will help us better understand how brain circuits can do what computers circuits so far cannot."
It is estimated that acquired language disorders, also known as aphasia, affect approximately 1 million people in the U.S., with 80,000 new cases diagnosed each year. Aphasia generally results from a stroke. Language ability is also often affected in those who suffer from neurodegenerative diseases such as Alzheimer's and from disorders such as autism. Understanding the basic circuitry of how speech is processed could help in treating these disorders.
Following on his previous work, Hickok, along with his colleagues, will use functional magnetic resonance imaging (fMRI) technology, which measures blood flow and allows scientists to map which brain regions become active during a task involving speech or language use. The team plans to conduct 200 fMRIs on healthy subjects, primarily at UCI.
Simultaneously, the UCI team, together with researchers at the University of Iowa and USC will study the language abilities of approximately 50 people who have suffered a stroke affecting some region of the brain. This information will allow the scientists to correlate different types of language deficits with damage to different brain regions. The data from stroke patients will then be compared with the results of the fMRI scans. Hickok's previous work on this project was restricted to functional imaging studies of healthy individuals.
"Comparison of functional imaging data from healthy brains with information from patients who have lesions is crucial," Hickok said. "Imaging can tell us what areas of the brain are active as the brain circuits process language, but it does not tell us precisely what those areas are responsible for. A brain area can be active but not be critically involved in speech or language. By studying stroke patients, we can determine which brain areas are important for a particular language function."
The study is one of 600 supported or conducted by NIDCD. Established in 1988, the institute is mandated to conduct and support biomedical and behavioral research and research training in the normal and disordered processes of hearing, balance, smell, taste, voice, speech and language.
Hickok also has been named director of the newly created Center for Cognitive Neuroscience, which will be housed in UCI's School of Social Sciences.
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