Featured Research

from universities, journals, and other organizations

Brain Imaging Reveals New Language Circuits

Date:
December 28, 2004
Source:
John Wiley & Sons, Inc.
Summary:
The language network of the brain seemed simpler in the past. One brain area was recognized to be critical for the production of language, another for its comprehension. A dense bundle of nerve fibers connected the two. But there have always been naysayers who pointed to evidence that failed to fit this tidy picture. Now a study employing a powerful variant of magnetic resonance imaging (MRI) confirms these suspicions.

The language network of the brain seemed simpler in the past. One brain area was recognized to be critical for the production of language, another for its comprehension. A dense bundle of nerve fibers connected the two.

Related Articles


But there have always been naysayers who pointed to evidence that failed to fit this tidy picture. Now a study employing a powerful variant of magnetic resonance imaging (MRI) confirms these suspicions. The study will be published December 13, 2004 in the online edition of Annals of Neurology (http://www.interscience.wiley.com/journal/ana).

"We were surprised that the two classical language areas were densely connected to a third area, whose presence had already been suspected but whose connections with the classical network were unknown," said lead author Marco Catani, M.D., of the Institute of Psychiatry at King's College London.

The authors dubbed this language area "Geschwind's territory" in honor of the American neurologist Norman Geschwind who championed its linguistic significance decades ago.

Language is generated and understood in the cortex, the outermost covering of the brain. Paul Broca and Carl Wernicke, 19th Century neurologists, noted that damage to specific cortical areas, which came to bear their names, produced primarily language production or language processing disorders, but not both. A large bundle of nerve fibers was found to connect Broca's and Wernicke's areas, and damage to this pathway also produced language disorders, or aphasias.

However, even in the 19th Century, there were bits of evidence that other brain areas play some role in language, though these have remained enigmatic, as scientists could not use animal models to probe language networks in the same way they could visual or movement networks in the brain.

In the last few decades, advanced brain imaging techniques such as CT, PET, and more recently, MRI have allowed scientists to begin studying these areas in living humans.

Standard MRI, by itself a powerful innovation, shows the major tissue structures of the brain. A variant called "functional" MRI even allows researchers to identify which areas are being used during different tasks, including producing and comprehending language.

Diffusion tensor (DT) MRI has gained prominence in the past decade because it reveals in greater detail the nerve fiber connections through which different brain regions form communication networks.

With DT-MRI, Catani and his colleagues found a separate, roundabout route that connects Broca's and Wernicke's areas via a region in the parietal lobe of the cortex, which Geschwind had pointed out as an important language region already in the 1960s.

"There are clues that the parallel pathway network we found is important for the acquisition of language in childhood," said Catani. "Geschwind's territory is the last area in the brain to mature, the completion of its maturation coinciding with the development of reading and writing skills. An important future line of study will be to examine the maturation of this area and its connections in the context of autism and dyslexia."

The fact that these pathways appear to exist – in more rudimentary forms – in the brains of monkeys may also have bearing on the search for the evolutionary origins of language.

"These data suggest that language evolved, in part, from changes in pre-existing networks, not through the appearance of new brain structures," said Catani.

"This method provides another example of the remarkable versatility of MRI technology," said Marsel Mesulam, M.D., of Northwestern University in Chicago, Illinois, whose editorial will accompany the print publication of the article.

"It is theoretically possible to combine diffusion tensor imaging with functional MRI so as to reveal the connectivity of brain areas with identified specializations," said Mesulam. "This method can be applied anywhere in the brain. Revealing the connections of the human brain will constitute the next frontier in the field of cognitive neurology."

###

Article: "Perisylvian Language Networks of the Human Brain," Marco Catani, Derek K. Jones, and Dominic H. Ffytche, Annals of Neurology; Published Online: December 13, 2004 (DOI: 10.1002/ana.20319).

Editorial: "Imaging Connectivity in the Human Cerebral Cortex: The Next Frontier?" Marsel Mesulam, Annals of Neurology (DOI: 10.1002/ana.20368).

About the Annals of Neurology:

The Annals of Neurology, the preeminent neurological journal worldwide, is published by the American Neurological Association, the world's oldest and most prestigious neurological association. The 1,500 members of the ANA--selected from among the most respected academic neurologists and neuroscientists in North America and other countries--are devoted to furthering the understanding and treatment of nervous system disorders. For more information, visit http://www.aneuroa.org.


Story Source:

The above story is based on materials provided by John Wiley & Sons, Inc.. Note: Materials may be edited for content and length.


Cite This Page:

John Wiley & Sons, Inc.. "Brain Imaging Reveals New Language Circuits." ScienceDaily. ScienceDaily, 28 December 2004. <www.sciencedaily.com/releases/2004/12/041220023913.htm>.
John Wiley & Sons, Inc.. (2004, December 28). Brain Imaging Reveals New Language Circuits. ScienceDaily. Retrieved November 26, 2014 from www.sciencedaily.com/releases/2004/12/041220023913.htm
John Wiley & Sons, Inc.. "Brain Imaging Reveals New Language Circuits." ScienceDaily. www.sciencedaily.com/releases/2004/12/041220023913.htm (accessed November 26, 2014).

Share This


More From ScienceDaily



More Mind & Brain News

Wednesday, November 26, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Are Female Bosses More Likely To Be Depressed?

Are Female Bosses More Likely To Be Depressed?

Newsy (Nov. 24, 2014) — A new study links greater authority with increased depressive symptoms among women in the workplace. Video provided by Newsy
Powered by NewsLook.com
Winter Can Cause Depression — Here's How To Combat It

Winter Can Cause Depression — Here's How To Combat It

Newsy (Nov. 23, 2014) — Millions of American suffer from seasonal depression every year. It can lead to adverse health effects, but there are ways to ease symptoms. Video provided by Newsy
Powered by NewsLook.com
Could Your Genes Be The Reason You're Single?

Could Your Genes Be The Reason You're Single?

Newsy (Nov. 21, 2014) — Researchers in Beijing discovered a gene called 5-HTA1, and carriers are reportedly 20 percent more likely to be single. Video provided by Newsy
Powered by NewsLook.com
Milestone Birthdays Can Bring Existential Crisis, Study Says

Milestone Birthdays Can Bring Existential Crisis, Study Says

Newsy (Nov. 21, 2014) — Researchers find that as people approach new decades in their lives they make bigger life decisions. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins