Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Trigger for Brain Plasticity Identified

11.08.2008
Researchers have long sought a factor that can trigger the brain’s ability to learn – and perhaps recapture the “sponge-like” quality of childhood. In the August 8 issue of the journal Cell, neuroscientists at Children’s Hospital Boston report that they’ve identified such a factor, a protein called Otx 2.

Otx2 helps a key type of cell in the cortex to mature, initiating a critical period -- a window of heightened brain plasticity, when the brain can readily make new connections.

The work was done in a mouse model of the visual system, a classic model for understanding how the brain sets up its wiring in response to input from the outside world. But Takao Hensch, PhD, of the Neurobiology Program and Department of Neurology at Children’s, the study’s senior investigator, speculates that there may be similar factors from the auditory, olfactory and other sensory systems that help time critical periods. Timing is important, because the brain needs to rewire itself at the right moment -- when it's getting the optimal sensory input.

“If the timing is off, the brain won't set up its circuits properly,” Hensch says.

Being able to control the timing of critical periods in different parts of the brain could possibly ameliorate developmental disorders such as autism, in which researchers believe critical periods may be inappropriately accelerated or delayed. Retriggering a critical period might also help people learn more readily after childhood – acquiring a new language, developing musical abilities or recovering from stroke or brain injury, for example.

Interestingly, Hensch and colleagues found that the brain cells that switch on critical periods in the visual system (parvalbumin cells) don’t actually make Otx2 themselves. Instead, Otx2 is sent by the retina. In essence, the eye is telling the brain, "The eyes are ready and seeing properly -- you can rewire now."

"The eye is telling the brain when to become plastic, rather than the brain developing on its own clock," says Hensch, who is also a professor at Harvard Medical School and at Harvard University’s Department of Molecular & Cellular Biology. “The idea that this class of molecular messenger is passed from cell to cell is considered unorthodox in cell biology.” This idea, however, has long been advocated by Dr. Alain Prochiantz of the Ecole Normale Superieure (Paris) and College de France, Hensch’s collaborator and a coauthor on the study.

It was previously known that when parvalbumin cells mature, they set up inhibitory circuits in the cortex, balancing the existing excitatory circuits. Hensch and others have shown that setting up inhibitory circuits is key in launching critical periods. “Early excitatory input is important to make first contacts between neurons,” Hensch explains. “But then, at the next stage, you need inhibition.”

In the current study, Hensch and colleagues demonstrated that when mice are reared in the dark, thus getting no visual input, Otx2 remains in the retina. Only when the mice received full visual input did Otx2 begin to appear in the cortex, and only then did parvalbumin cells start to mature.

In other experiments, the researchers injected Otx2 directly into the cortex. The parvalbumin cells matured, even when the mice were kept in the dark. Finally, when Otx2 synthesis was blocked in the eye, parvalbumin cell functions failed to mature.

Otx2 has an unusual derivation: it is originally produced during embryonic development; without it, mice don't develop heads. Production then stops, but some days after birth, it reappears in parvalbumin cells. “The nervous system is recycling an embryonic factor to induce brain plasticity,” says Hensch.

Hensch, who last fall won the highly competitive NIH Director’s Pioneer Award, is also interested in the transport mechanism that propagates Otx2 from the retina to the cortex. He speculates that Otx2 itself could be a carrier for factors you’d want to deliver to the brain, envisioning eye drops for brain disorders such as schizophrenia, in which parvalbumin cells don't properly mature.

The study was funded by the Human Frontiers Science Program (Strasbourg), the Fondation pour La Recherche Medicale, and in part by RIKEN (Japan) and the Japanese Ministry of Science, Education and Technology (MEXT). Sayaka Sugiyama, PhD, was first author.

Children’s Hospital Boston is home to the world’s largest research enterprise based at a pediatric medical center, where its discoveries have benefited both children and adults since 1869. More than 500 scientists, including eight members of the National Academy of Sciences, 11 members of the Institute of Medicine and 12 members of the Howard Hughes Medical Institute comprise Children’s research community. Founded as a 20-bed hospital for children, Children’s Hospital Boston today is a 397-bed comprehensive center for pediatric and adolescent health care grounded in the values of excellence in patient care and sensitivity to the complex needs and diversity of children and families. Children’s also is the primary pediatric teaching affiliate of Harvard Medical School.

James Newton | Newswise Science News
Further information:
http://www.hms.harvard.edu/

Further reports about: Harvard Otx2 Otx2 synthesis brain plasticity cell biology

More articles from Studies and Analyses:

nachricht New model connects respiratory droplet physics with spread of Covid-19
21.07.2020 | University of California - San Diego

nachricht Risk of infection with COVID-19 from singing: First results of aerosol study with the Bavarian Radio Chorus
03.07.2020 | Klinikum der Universität München

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

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

Im Focus: ScanCut project completed: laser cutting enables more intricate plug connector designs

Scientists at the Fraunhofer Institute for Laser Technology ILT have come up with a striking new addition to contact stamping technologies in the ERDF research project ScanCut. In collaboration with industry partners from North Rhine-Westphalia, the Aachen-based team of researchers developed a hybrid manufacturing process for the laser cutting of thin-walled metal strips. This new process makes it possible to fabricate even the tiniest details of contact parts in an eco-friendly, high-precision and efficient manner.

Plug connectors are tiny and, at first glance, unremarkable – yet modern vehicles would be unable to function without them. Several thousand plug connectors...

Im Focus: New Strategy Against Osteoporosis

An international research team has found a new approach that may be able to reduce bone loss in osteoporosis and maintain bone health.

Osteoporosis is the most common age-related bone disease which affects hundreds of millions of individuals worldwide. It is estimated that one in three women...

Im Focus: AI & single-cell genomics

New software predicts cell fate

Traditional single-cell sequencing methods help to reveal insights about cellular differences and functions - but they do this with static snapshots only...

Im Focus: TU Graz Researchers synthesize nanoparticles tailored for special applications

“Core-shell” clusters pave the way for new efficient nanomaterials that make catalysts, magnetic and laser sensors or measuring devices for detecting electromagnetic radiation more efficient.

Whether in innovative high-tech materials, more powerful computer chips, pharmaceuticals or in the field of renewable energies, nanoparticles – smallest...

Im Focus: Tailored light inspired by nature

An international research team with Prof. Cornelia Denz from the Institute of Applied Physics at the University of Münster develop for the first time light fields using caustics that do not change during propagation. With the new method, the physicists cleverly exploit light structures that can be seen in rainbows or when light is transmitted through drinking glasses.

Modern applications as high resolution microsopy or micro- or nanoscale material processing require customized laser beams that do not change during...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“Conference on Laser Polishing – LaP 2020”: The final touches for surfaces

23.07.2020 | Event News

Conference radar for cybersecurity

21.07.2020 | Event News

Contact Tracing Apps against COVID-19: German National Academy Leopoldina hosts international virtual panel discussion

07.07.2020 | Event News

 
Latest News

Rare Earth Elements in Norwegian Fjords?

06.08.2020 | Earth Sciences

Anode material for safe batteries with a long cycle life

06.08.2020 | Power and Electrical Engineering

Turning carbon dioxide into liquid fuel

06.08.2020 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>