( One teenager likes to snowboard off a c...)Study identifies gene in mice that may control risk-taking behavior in humans

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 aggressio
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Source:Fred Hutchinson Cancer Research Center