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Language Feature Unique To Human Brain Identified

Date:
March 24, 2008
Source:
Emory University
Summary:
Researchers have identified a language feature unique to the human brain that is shedding light on how human language evolved. The study marks the first use of diffusion tensor imaging, a noninvasive imaging technique, to compare human brain structures to those of chimpanzees, our closest living relative.
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Researchers have compared human brain structures to those of chimpanzees to identify a language feature unique to the human brain that is shedding light on how human language evolved.
Credit: iStockphoto/Igor Karon

Researchers at the Yerkes National Primate Research Center, Emory University, have identified a language feature unique to the human brain that is shedding light on how human language evolved. The study marks the first use of diffusion tensor imaging (DTI), a non-invasive imaging technique, to compare human brain structures to those of chimpanzees, our closest living relative.

To explore the evolution of human language, Yerkes researcher James Rilling, PhD, and his colleagues studied the arcuate fasciculus, a pathway that connects brain regions known to be involved in human language, such as Broca's area in the frontal lobe and Wernicke's area in the temporal lobe. Using DTI, researchers compared the size and trajectory of the arcuate fasciculus in humans, rhesus macaques and chimpanzees.

According to Rilling, "The human arcuate fasiculus differed from that of the rhesus macaques and chimpanzees in having a much larger and more widespread projection to areas in the middle temporal lobe, outside of the classical Wernicke's area. We know from previous functional imaging studies that the middle temporal lobe is involved with analyzing the meanings of words. In humans, it seems the brain not only evolved larger language regions but also a network of fibers to connect those regions, which supports humansÕ superior language capabilities."

"This is a landmark," said Yerkes researcher Todd Preuss, PhD, one of the study's coauthors. "Until DTI was developed, scientists lacked non-invasive methods to study brain connectivity directly. We couldn't study the connections of the human brain, nor determine how humans resemble or differ from other animals. DTI now makes it possible to understand how evolution changed the wiring of the human brain to enable us to think, act and speak like humans."

The study will be published in the online version of Nature Neuroscience.


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The above post is reprinted from materials provided by Emory University. Note: Materials may be edited for content and length.


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Emory University. "Language Feature Unique To Human Brain Identified." ScienceDaily. ScienceDaily, 24 March 2008. <www.sciencedaily.com/releases/2008/03/080323210220.htm>.
Emory University. (2008, March 24). Language Feature Unique To Human Brain Identified. ScienceDaily. Retrieved July 31, 2015 from www.sciencedaily.com/releases/2008/03/080323210220.htm
Emory University. "Language Feature Unique To Human Brain Identified." ScienceDaily. www.sciencedaily.com/releases/2008/03/080323210220.htm (accessed July 31, 2015).

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