Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Study identifies gene in mice that may control risk-taking behavior in humans

27.09.2005


One teenager likes to snowboard off a cliff. Another prefers to read a book and wouldn’t think of trading places. Why these differences exist is a mystery, but for the first time researchers have identified a possible genetic explanation behind risk-seeking behavior.



Scientists at Fred Hutchinson Cancer Research Center have found that a specific neurodevelopmental gene, called neuroD2, is related to the development of an almond-shaped area of the brain called the amygdala, the brain’s emotional seat. This gene also controls emotional-memory formation and development of the fear response, according to research led by James Olson, M.D., Ph.D., associate member of the Clinical Research Division at the Hutchinson Center.

The findings will be published in the early online edition of the Proceedings of the National Academy of Sciences the week of Sept. 26. Olson and colleagues studied mice with a single copy of the neuroD2 gene and found they had an impaired ability to form emotional memories and conditioned fear.


"Most of us are familiar with the fact that we can remember things better if those memories are formed at a time when there is a strong emotional impact – times when we are frightened, angry or falling in love," he said. "That’s called emotional-memory formation. The amygdala is the part of the brain that is responsible for formation of emotional memory."

In the brain’s early development, the neuroD2 gene encodes the neuroD2 protein to transform undifferentiated stem cell-like cells into neurons, or brain cells. Under the microscope, certain areas of the amygdala were absent in mice with no neuroD2 gene. In mice with just one copy of neuroD2, researchers also found fewer nerve cells in the amygdala.

Researchers conducted experiments on mice with a single copy of the neuroD2 gene to test the theory that only having one copy of the gene impacts emotional learning and the development of traits such as fear and aggression. Long-term behavioral studies of mice with no neuroD2 genes were not possible because these mice die within a few weeks of birth.

In one experiment, mice were exposed to an adverse stimulus coupled with a non-adverse stimulus, a tone followed by a mild foot shock. Normal mice crouch down and stop moving the next time they hear the tone, a physiologic response that indicates they expected a shock. The mice remembered the experience. However, those with a single copy of the neuroD2 gene did not respond to the tone like the normal mice did, researchers found. These mice did not freeze their movements as often in anticipation of the mild shock.

To assess the level of unconditioned fear in mice with a single copy of the neuroD2 gene, researchers put them into a situation that would elicit a fear response in normal mice. They used a maze elevated 40 centimeters above a tabletop where mice had the option to walk along narrow, unprotected walkways or arms with protective walls. Half of the time the neuroD2-deficient mice chose the unprotected arms, whereas the normal mice almost always chose the protected arms, Olson said.

"All of this matches very well with previous observations that the amygdala is responsible for fear, anxiety and aggression," said Olson. "Now we’re seeing that the neuroD2-deficient mice, when compared to normal littermates, show a profound difference in unconditioned anxiety levels as well as their ability to form emotional memories."

Olson noted that the dosage of neuroD2, one copy versus the normal two copies, was important for how much fear, anxiety and aggression the mice displayed.

"These findings are new to science," said Olson, who is also an associate professor in pediatrics at the University of Washington School of Medicine. "The contribution we have made is showing that neuroD2 is related to the development of the amygdala. This is the first time that a specific neurodevelopmental gene has been related to these emotional activities in the brain."

Further research is needed that one day could explain why some people react the way they do to fear, or why they take risks, Olson said. "The question is, are there differences in the neuroD2 gene-coding sequence or differences downstream of the neuroD2 pathway during brain development that could affect either psychiatric or emotional functions in humans? It’s a completely unexplored question; it is the immediate next question you would go to if you want to understand how this gene impacts human behavior."

Dean Forbes | EurekAlert!
Further information:
http://www.fhcrc.org

More articles from Studies and Analyses:

nachricht Multi-year study finds 'hotspots' of ammonia over world's major agricultural areas
17.03.2017 | University of Maryland

nachricht Diabetes Drug May Improve Bone Fat-induced Defects of Fracture Healing
17.03.2017 | Deutsches Institut für Ernährungsforschung Potsdam-Rehbrücke

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: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Northern oceans pumped CO2 into the atmosphere

27.03.2017 | Earth Sciences

Fingerprint' technique spots frog populations at risk from pollution

27.03.2017 | Life Sciences

Big data approach to predict protein structure

27.03.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>