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 When a fish becomes fluid
17.12.2018 | Institute of Science and Technology Austria

nachricht Some brain tumors may respond to immunotherapy, new study suggests
11.12.2018 | Columbia University Irving Medical Center

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: Data storage using individual molecules

Researchers from the University of Basel have reported a new method that allows the physical state of just a few atoms or molecules within a network to be controlled. It is based on the spontaneous self-organization of molecules into extensive networks with pores about one nanometer in size. In the journal ‘small’, the physicists reported on their investigations, which could be of particular importance for the development of new storage devices.

Around the world, researchers are attempting to shrink data storage devices to achieve as large a storage capacity in as small a space as possible. In almost...

Im Focus: Data use draining your battery? Tiny device to speed up memory while also saving power

The more objects we make "smart," from watches to entire buildings, the greater the need for these devices to store and retrieve massive amounts of data quickly without consuming too much power.

Millions of new memory cells could be part of a computer chip and provide that speed and energy savings, thanks to the discovery of a previously unobserved...

Im Focus: An energy-efficient way to stay warm: Sew high-tech heating patches to your clothes

Personal patches could reduce energy waste in buildings, Rutgers-led study says

What if, instead of turning up the thermostat, you could warm up with high-tech, flexible patches sewn into your clothes - while significantly reducing your...

Im Focus: Lethal combination: Drug cocktail turns off the juice to cancer cells

A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.

The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...

Im Focus: New Foldable Drone Flies through Narrow Holes in Rescue Missions

A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.

Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

ICTM Conference 2019: Digitization emerges as an engineering trend for turbomachinery construction

12.12.2018 | Event News

New Plastics Economy Investor Forum - Meeting Point for Innovations

10.12.2018 | Event News

EGU 2019 meeting: Media registration now open

06.12.2018 | Event News

 
Latest News

Pressure tuned magnetism paves the way for novel electronic devices

18.12.2018 | Materials Sciences

New type of low-energy nanolaser that shines in all directions

18.12.2018 | Physics and Astronomy

NASA research reveals Saturn is losing its rings at 'worst-case-scenario' rate

18.12.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>