The network -- called the arcuate fasciculus -- connects brain regions necessary for the comprehension and production of speech. Researchers at the Yerkes National Primate Research Center at Emory University made their discovery using a new, non-invasive imaging technique called diffusion tensor imaging, or DTI.
The scientists used DTI to measure the size and trajectory of the arcuate fasciculus in humans, rhesus macaques and chimpanzees.
"The human arcuate fasciculus 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," said Professor James Rilling. "In humans, it seems the brain not only evolved larger language regions, but also a network of fibers to connect those regions (that) support humans' superior language capabilities."
"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," study co-author Professor Todd Preuss said.
The study findings appeared in the online version of the journal Nature Neuroscience.