Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers uncover novel mechanism that balances the sizes of functional areas in the brain

11.09.2007
Researchers uncover novel mechanism that balances the sizes of functional areas in the brain

In the cerebral cortex, the brain’s powerful central processing unit responsible for higher functions, specialized subdivisions known as areas are laid out like a map, but little is known about the genetic forces that shape the geography of our brains.

In this week’s advance online edition of Nature Neuroscience, an international collaboration between researchers at the Salk Institute for Biological Studies and the Telethon Institute of Genetics and Medicine in Italy reports the discovery of a novel function for a factor that negotiates the borders between areas and balances their sizes and positions relative to each other.

The factor, COUP-TF1, ensures that the frontal areas don’t claim too much cortical real estate. Without COUP-TF1 keeping the frontal areas in check, they undergo massive expansion squeezing and pushing neighboring sensory areas literally to the back of the brain.

The findings show how the cortex is properly parceled into “frontal” areas that control higher functions related to emotions and the movements of our bodies versus areas that interpret our sensory environment and allow us to see, hear and feel. Because primary areas in humans differ by two-fold or more in the normal population, these findings may explain these size differences, which appear to account, at least in part, for differences between individuals in behavior and skills.

“Until now, there has been only one other gene, Emx2, that everybody agrees on directly controls area patterning,” explains co-senior author Dennis O’Leary, Ph.D., professor in the Molecular Neurobiology Laboratory at the Salk Institute. “Our current understanding of this process is the proverbial tip of the iceberg. We are only beginning to define the mechanisms that determine the area identity of neurons in the cortex.”

The back of the cortex is predominantly specialized to process vision, whereas the front of the cortex handles motor functions and controls voluntary movement, as well as having a central role in higher cognitive functions. The area right above the ear trades in sounds and speech, while the somatosensory area located in the middle top of the head interprets information about touch and pain.

In previous studies, the O’Leary lab discovered that Emx2, a gene common to mice and men as is COUP-TF1, instructs progenitor cells to develop into visual neurons. “Emx2 is the gold standard for genes that impart area identity to cortical neurons,” says O’Leary. “When we increased the amount of Emx2, the visual area expanded at the expense of the frontal and somatosensory areas and vice versa.”

Just like the Emx2 gene, COUP-TF1 is normally most active in the back of the cortex, with its activity gradually tapering off toward the front. Both genes code for transcription factors — which operate by controlling a cascade of other genes — hinting at a possible role for COUP-TF1 in area patterning as well.

Completely eliminating the gene in lab mice through genetic engineering – a mainstay of scientists trying to figure out the function of a particular gene – did not clarify the roles of COUP-TF1. “Mice without COUP-TF1 have many defects and die a few days after birth before functional areas can be defined,” explains co-first author Shen-Ju Chou, a postdoctoral researcher in the O’Leary lab.

So O’Leary and his team collaborated with Italian researchers, led by Dr. Michele Studer, who is co-senior author with O’Leary of the study, to develop mice in which COUP-TF1 can be selectively removed from progenitor cells in the cortex just before they start generating cortical neurons. The mice survive to be adults and appear quite normal. Their cortical landscape, however, is a different matter.

“We were surprised by what we saw,” Chou says. “The frontal areas took over most of the cortex, while the sensory areas were drastically reduced in size and relegated to a small domain at the back of the brain.” The overall size of the cortex stayed the same.

“Our findings imply that Emx2 and COUP-TF1 work in opposing ways,” says O’Leary. “While Emx2 works in a positive manner to specify the area identity of visual neurons, the presence of COUP-TF1 prevents progenitor cells from taking on a motor area identity.”

Although the mice lacking COUP-TF1 in their cortex do not have any obvious sensory or motor problems, the researchers believe that a closer look will reveal substantial deficits. Their prediction is based on a study published by O’Leary and his colleagues earlier this year. They found that individual areas must be the right size relative to each other or mice will underperform in tests of their skills at the relevant behaviors.

Gina Kirchweger | EurekAlert!
Further information:
http://www.salk.edu

Further reports about: Coup-Tf1 Emx2 O’Leary balances cortical frontal mechanism neurons novel

More articles from Life Sciences:

nachricht Bacteria as pacemaker for the intestine
22.11.2017 | Christian-Albrechts-Universität zu Kiel

nachricht Researchers identify how bacterium survives in oxygen-poor environments
22.11.2017 | Columbia 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: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Corporate coworking as a driver of innovation

22.11.2017 | Business and Finance

PPPL scientists deliver new high-resolution diagnostic to national laser facility

22.11.2017 | Physics and Astronomy

Quantum optics allows us to abandon expensive lasers in spectroscopy

22.11.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>