Gene Mutation Brings Stronger Recall of Bad Memories
> 8/2/2007 2:26:48 PM

For some people, a natural disaster is a frightening episode that becomes an exciting story to tell. For others, it is a crippling memory that replays again and again. No one is able to predict which people will develop PTSD from identical experiences, but scientists have taken a large step towards understanding why some people are more vulnerable to traumatizing memories.

Dr. Dominique Querain from the University of Zurich published a study in the most recent edition of Nature about the role of noradrenaline in emotional memory. Noradrenaline distribution is governed by a deletion variant of ADRA2B, a gene present in 30% of Caucasians and 12% of Africans. Dr. Querain performed an experiment for each of these groups.

The first experiment asked Caucasian participants to examine pictures with happy, neutral, or upsetting emotional connotation. When they were asked to describe these pictures later, an obvious pattern emerged. Participants with the ADRA2B variation were able to recall many more details about emotional pictures even though their memory of neutral pictures was no more accurate. This variant gene could be very useful, because the most important moments of our lives are often complex and emotional. It can be pleasant to recall our first kiss and life-saving to remember the face of a brutal assailant.

The second experiment asked survivors of the Rwandan genocide to describe their experiences. Again, participants with the ADRA2B variant were able to recall more details. Their memories were more vivid and less likely to decay with time.

These findings confirm another study in Nature by Dr. Larry Cahill. The New York Times reported on his experiment, which showed that subjects on noradrenaline-blocking drugs were less capable of recalling details about emotional scenes the week after witnessing them. This is not entirely unprecdented, because we have previously discussed cdk5, another chemical that revealed its role in emotional memory recall when blocked in mice. Noradrenaline has long been suspected of mediating emotional memory, but this is the first time that the effect found in mice has been clearly observed in humans. Studies in the past decades, like this one, which claims that noradrenaline has nothing to do with emotional or long-term memory, now stand corrected.

These breakthroughs in understanding the genetic and chemical mechanism for emotional memory have important implications for PTSD treatment. Genetic screenings will be able to warn people that they may have trouble with traumatic memories. This can alert psychiatrists to be on the lookout for symptoms from patients with traumatic histories. The military could screen recruits so that those with the gene variant are not put into combat-heavy positions. For those who have the gene or are likely to face traumatic events, the drug findings by Dr. Cahill offer hope. It may be possible to alter the levels of noradrenaline in the brain during disturbing experiences so that you are not haunted by terrible memories.


Interesting post...thanks for sharing.The way you react to stress factors in on how you feel. You could feel depressed, if you react to stress in negative light. Stress is a part of life and hits us every single day we live. There is no escape for stress.Stress overall is changes small and large in which you must regulate to its actions. Most people believe stress is a negative act. However, stress can work in your favor. Stress coming from injury, illnesses, and death can also be, turned into positive influences.
Posted by: Self Help Zone 8/3/2007 3:56:13 AM

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