Corporate Banner
Satellite Banner
Genomics
Scientific Community
 
Become a Member | Sign in
Home>News>This Article
  News
Return

Gene in Mice Controls Risk-Taking Behavior in Humans

Published: Wednesday, September 28, 2005
Last Updated: Wednesday, September 28, 2005
Bookmark and Share
Scientists have studied mice with a single copy of the neuroD2 gene and found they had an impaired ability to form emotional memories and conditioned fear.

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.

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.”


Further Information

Join For Free

Access to this exclusive content is for Technology Networks Premium members only.

Join Technology Networks Premium for free access to:

  • Exclusive articles
  • Presentations from international conferences
  • Over 2,900+ scientific posters on ePosters
  • More than 4,200+ scientific videos on LabTube
  • 35 community eNewsletters


Sign In



Forgotten your details? Click Here
If you are not a member you can join here

*Please note: By logging into TechnologyNetworks.com you agree to accept the use of cookies. To find out more about the cookies we use and how to delete them, see our privacy policy.

Related Content

Study Reveals Why Certain Ovarian Cancers Develop Resistance to Platinum-Based Chemotherapy
Researchers identified a mechanism that explains why some recurrent ovarian tumors become resistant to treatment with commonly used platinum-based chemotherapy drugs.
Wednesday, February 13, 2008
Scientific News
Biosensors on Demand
New strategy results in custom "designer proteins" for sensing a variety of molecules.
Unique Mechanism for a High-Risk Leukemia
Researchers uncovered the aberrant mechanism underlying a notoriously treatment-resistant acute lymphoblastic leukemia subtype; findings offer lessons for understanding all cancers.
NIH Researchers Identify Striking Genomic Signature for Cancer
Institute has identified striking signature shared by five types of cancer.
CRI Develops Innovative Approach for Identifying Lung Cancer
Institute has developed innovative approach for identifying processes that fuel tumor growth in lung cancer patients.
The Spice of Life
Scientists discover important genetic source of human diversity.
Removing Race from Human Genetic Research
A group of scientists are urging their colleagues to take a step forward and stop using racial categories when researching and studying human genetics.
Tick Genome Reveals Secrets of a Successful Bloodsucker
NIH-funded study could lead to new tick control methods.
Light Signals from Living Cells
Fluorescent protein markers delivered under high pressure.
Counting Cancer-busting Oxygen Molecules
Researchers from the Centre for Nanoscale BioPhotonics (CNBP), an Australian Research Centre of Excellence, have shown that nanoparticles used in combination with X-rays, are a viable method for killing cancer cells deep within the living body.
Genomic Signature Shared by Five Types of Cancer
National Institutes of Health researchers have identified a striking signature in tumor DNA that occurs in five different types of cancer.
Skyscraper Banner

Skyscraper Banner
Go to LabTube
Go to eposters
 
Access to the latest scientific news
Exclusive articles
Upload and share your posters on ePosters
Latest presentations and webinars
View a library of 1,800+ scientific and medical posters
2,900+ scientific and medical posters
A library of 2,500+ scientific videos on LabTube
4,200+ scientific videos
Close
Premium CrownJOIN TECHNOLOGY NETWORKS PREMIUM FOR FREE!