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A University of Arizona scientist who has specialized in studying how fireflies and other creatures communicate has won a million-dollar grant to conduct a pioneering 5-year study on the roles that attention and memory play when the human brain hears and processes spoken language.

"This is the chance to study the ultimate form of animal communication -- language," said Thomas A. Christensen of UA's department of speech, language and hearing sciences (SLHS). "Humans have evolved a very sophisticated symbolic form of communication. Language affects how we think, what we believe, how we interact with each other. I'd even go so far as to say that our future as a species depends本论文由英语论文网 www.51lunwen.org整理提供 on understanding how we communicate. But very little is known about what's going on in the brain when we're having a simple conversation."

Until recently, Christensen was a research scientist with the Arizona Research Laboratories' Division of Neurobiology, studying olfactory communication (the sense of smell) in insects. His research is grounded in the areas of learning and memory, systems physiology and animal communication. Encouraged by Elena Plante, head of the SLHS department, he applied for a $1 million career development award from the National Institute of Deafness and Other Communication Disorders. The grant was awarded in April.

The grant will take his career -- and biomedical science -- in new directions. Christensen will use UA's state-of-the-art magnetic resonance imaging (MRI) facilities to map the areas and networks within the brain linked to language, attention and memory. The UA's advanced MRI is a non-invasive imaging tool that is sensitive enough to show exactly what parts of the brain are involved when a person listens to another human voice.

"What you read in the text books is that if you're right handed, then language is localized to the left hemisphere of your brain," Christensen said. "I found out right away -- that's just not true. Analyzing a human voice also involves the right hemisphere and even parts of the cerebellum." The cerebellum i本论文由英语论文网 www.51lunwen.org整理提供s a large part of the brain that serves to coordinate voluntary movements, posture, and balance in humans.

"These MRI images destroy the myth that you're only using about 10 percent of your brain for any particular task," Christensen said. "The crux of this grant is to learn more about the language, attention and memory centers in the brain, and also about the complex interactions between them."

Inside the scanner, volunteer subjects don headphones and perform simple language discrimination tasks in Christensen's experiments. They're asked to respond by pressing a button when they hear words that fall into a certain semantic category -- the name of an animal, for example. Then, to make the task a bit harder, subjects are asked to respond only when they hear a woman's voice speak a word in the chosen category. The task taxes attention even more when subjects are asked 本论文由英语论文网 www.51lunwen.org整理提供to respond to a woman's voice speaking a 'target' word in one ear at the same time a man's voice is speaking words in the other.
The MRI scanner records activity throughout the 45-minute sessions, revealing multiple regions and networks, some deep within the brain, that scientists didn't suspect were involved when the brain liste本论文由英语论文网提供整理，提供论文代写，英语论文代写，代写论文，代写英语论文，代写留学生论文，代写英文论文，留学生论文代写相关核心关键词搜索。