Brain mechanism may help some cope better in stressful situations

Oct 22 2007

According to researchers in the U.S. a mechanism found in some people's brain could be the key to them staying relaxed in stressful situations.

The scientists say a difference in brain chemistry may explain why some people are more prone to post-traumatic stress disorder and why some cope well with stress.

Experts say new evidence is increasingly showing that responses to stress are linked to chemical mechanisms in the brain and people differ widely in their responses to stressful situations, some people seem highly resilient to stress while others struggle to cope.

The researchers, from the University of Texas Southwestern Medical Centre, studied the brains of normal mice put under a stressful situation in the form of a larger more aggressive mouse.

Some of the mice coped with the stress well and others became timid and withdrew from social interaction and the researchers found a key pathway in those who coped well with stress, and those who did not.

It seems in the mice who did not cope well with stress, nerve cells fired signals at a faster rate in two areas of the brain associated with pleasure and reward, releasing a substance called BDNF, which has previously been linked to poor coping.

The resilient mice had no increase in BDNF, probably because the neurons were firing less rapidly; blocking BDNF in the timid mice caused them to become more resistant to stress.

In mice who coped better with stress, there were also greater regulation of genes in the key brain regions, suggesting resilience to such conditions is an active process rather than a lack of a response.

Dr. Vaishnav Krishnan who led the study says they have identified the ways in which the brain naturally copes with chronic stressful experiences.

Dr. Krishnan says the findings could lead to new treatments for conditions such as post-traumatic stress disorder and depression.

The researchers say preventing BDNF release in certain brain regions may be a way to increase coping with stress or depression, but simply blocking BDNF might also affect other systems, so the researchers must find a way to target the specific pathway involved in stress.

The study appears in the journal Cell.