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An animal rights group known as the Nonhuman Rights Project filed lawsuits in three New York courts this week in an...
Researchers have been hot on the trail of the elusive Denisovans, a type of ancient human known only by their DNA and...
Thousands of scientists in the Russian Academy of Sciences (RAS) are about to lose their jobs as a result of the...
Dyslexia, a learning disability that hinders reading, hasn't been associated with deficits in vision, hearing, or...
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Researchers have sequenced and analyzed the first two snake genomes, which represent two evolutionary extremes. The...
Snake venoms are remarkably complex mixtures that can stun or kill prey within minutes. But more and more researchers...
At age 30, Dutch biologist Freek Vonk has built up a respectable career as a snake scientist. But in his home country,...
- 5 December 2013 11:26 am , Vol. 342 , #6163
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Neural Disconnection May Trip Up Stutterers
2 August 2002 (All day)
Fibers in the brain that bridge a region governing speech and another controlling the tongue may be less robust in stutterers than nonstutterers, new research finds. The study is among the few that have analyzed the brains of stutterers and is the first to focus on the white matter that connects brain structures.
Stuttering afflicts 1% of adults and has been around since the dawn of history: It's referred to in the Bible and on Egyptian hieroglyphs, says David Rosenfield of Baylor College of Medicine in Houston, Texas. A year ago, neurologist Anne Foundas at Tulane University Health Sciences Center in New Orleans, Louisiana, and her colleagues found subtle differences between stutterers and nonstutterers in two language regions, called Wernicke's area and Broca's area.
Neurologist Christian Büchel and his colleagues at the University of Hamburg, Germany, recruited 15 confirmed stutterers and 15 nonstutterers to dig deeper into the neuroanatomy of stuttering. The researchers performed a type of brain imaging called diffusion tensor imaging (DTI), which highlights the brain's white matter--the long nerve fibers made up of axons that send messages between neurons. Fibers running between two regions in the left side of the brain--one a speech center near Wernicke's and Broca's, the other a motor control region for the tongue and larynx--were about 30% less tightly packed among those who stuttered, the team reports in the 3 August issue of The Lancet. That suggests either that stutterers have fewer axons in this tract or that the axons meander, says Büchel.
In stutterers, "the whole system seems to be disrupted at multiple sites," says Foundas. She wonders whether the differences in brain anatomy that her lab found might induce these nearby changes in white matter.