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 NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation

nachricht Pollen taxi for bacteria
18.07.2018 | Technische Universität München

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

NYSCF researchers develop novel bioengineering technique for personalized bone grafts

18.07.2018 | Life Sciences

Machine-learning predicted a superhard and high-energy-density tungsten nitride

18.07.2018 | Materials Sciences

Why might reading make myopic?

18.07.2018 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>