DALLAS March 31, 2010 UT Southwestern Medical Center researchers have found new clues that might help explain why some people are more susceptible to stress than others.
In a study of mice, the researchers determined that weeks after experiencing a stressful event, animals that were more susceptible to stress exhibited enhanced neurogenesis the birth of new nerve cells in the brain. Specifically, the cells that these animals produced after a stressful event survived longer than new brain cells produced by mice that were more resilient.
In addition, when researchers prevented neurogenesis in both stress-susceptible and resilient mice, the animals previously susceptible to stress became more resilient.
"This work shows that there is a period of time during which it may be possible to alter memories relevant to a social situation by manipulating adult-generated nerve cells in the brain," said Dr. Amelia Eisch, associate professor of psychiatry at UT Southwestern and senior author of the study, available in the Proceedings of the National Academy of Sciences. "This could eventually lead to a better understanding of why, in humans, there is an enormous variety of responses to stressful situations."
Mice that are susceptible to stress exhibit long-lasting social avoidance and depressive-like behavior after experiencing a stressful event, such as being placed in a cage with a more aggressive mouse. Resilient mice behave more like unstressed control animals. This animal model is commonly used in studies of stress and depression, as understanding the changes in the brain and behavior of the mice can shed light on stress-induced changes in the human brain and in human behavior.
In the study, the brain cells of both groups of mice responded in similar ways after a stressful event. But weeks later, researchers found that mice displaying social avoidance had more nerve cells in a region of the brain called the hippoc
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UT Southwestern Medical Center