Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Brain imaging reveals new language circuits

14.12.2004


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 study will be published December 13, 2004 in the online edition of Annals of Neurology. "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."

David Greenberg | EurekAlert!
Further information:
http://www.interscience.wiley.com/journal/ana
http://www.wiley.com

More articles from Life Sciences:

nachricht Link Discovered between Immune System, Brain Structure and Memory
26.04.2017 | Universität Basel

nachricht Researchers develop eco-friendly, 4-in-1 catalyst
25.04.2017 | Brown University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

From volcano's slope, NASA instrument looks sky high and to the future

27.04.2017 | Earth Sciences

Control of molecular motion by metal-plated 3-D printed plastic pieces

27.04.2017 | Materials Sciences

Move over, Superman! NIST method sees through concrete to detect early-stage corrosion

27.04.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>