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 Microscope measures muscle weakness
16.11.2018 | Friedrich-Alexander-Universität Erlangen-Nürnberg

nachricht Good preparation is half the digestion
16.11.2018 | Max-Planck-Institut für Stoffwechselforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: UNH scientists help provide first-ever views of elusive energy explosion

Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.

Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure

Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

European Space Talks: Weltraumschrott – eine Gefahr für die Gesellschaft?

23.10.2018 | Event News

 
Latest News

Purdue cancer identity technology makes it easier to find a tumor's 'address'

16.11.2018 | Health and Medicine

Good preparation is half the digestion

16.11.2018 | Life Sciences

Microscope measures muscle weakness

16.11.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>