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A GENE TO BETTER REMEMBER TRAUMATIC EVENTS --
Gene variant leads to more vivid recollections
of
emotionally powerful episodes, both good and
bad. Could be a step toward gene testing for
PTSD.
For more information on PTSD, use the VA
Watchdog search engine...click here...
http://www.yourvabenefits.org/ses
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Story here...
http://www.sciam.com/article
.cfm?articleID=18E4716D-E7F2-99DF
-351642C9346A93D3&chanID=sa007
Story below:
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A Gene to Better Remember Traumatic Events
Gene variant (found in 30 percent of Caucasian
population and 12 percent of African-Americans) leads to more vivid
recollections of emotionally powerful episodes—both good and bad
By Nikhil Swaminathan
It's generally accepted both inside and outside psychological circles
that the details surrounding emotional events—like scoring the winning
touchdown in a football game or a traumatic car accident—are easier to
recall than those associated with mundane occurrences.
A new study, appearing in this week's issue of Nature Neuroscience,
reports that those who carry a common variant of a gene called ADRA2B
may have better recall of emotionally charged moments than those who
lack the gene.
"This was a first proof of principle that we are able to identify genes
[specifically] related to emotional memory," says the new paper's lead
author Dominique de Quervain, a professor in the University of Zurich's
Division of Psychiatry Research. "[This work] may have consequences for
anxiety disorders where emotional memory plays a critical role."
From laboratory studies, this specific mutation of ADRA2B is known to
cause the deletion of three amino acids in the protein that it encodes.
This deletion disrupts the behavior of a receptor for the
neurotransmitter noradrenaline, which is known to be involved in
emotional memory.
According to the study's results, this receptor modification actually
improves the recall of emotional memories.
After genotyping 435 young Swiss adults, de Quervain's team presented
their subjects with 30 pictures in random order for four seconds each.
Each scene fell into one of three emotional arousal categories: neutral
(such as a secretary on the phone); positive (a grandfather playing with
his grandchildren); or negative (a car accident involving a head wound).
After viewing all the pictures, subjects had to write short descriptions
of each scene.
Subjects with the gene variant—which is believed to be in 30 percent of
the U.S. Caucasian population and 12 percent of African-Americans—could
recall up to 80 percent of the emotionally arousing scenes.
(Participants without the gene could only remember 40 percent of them.)
"If that deletion variant enhances emotional memories," in the context
of an experiment, de Quervain says, "we thought maybe it also enhances
very [real] emotional memories". The team then tested 202 refugees from
the 1994 Rwandan civil war—133 who had been diagnosed with
post-traumatic stress disorder (PTSD). Among this population, subjects
with the gene variant reported (and reexperienced) more distressing
wartime memories than those without the variant—regardless of PTSD
status.
"Traumatic memory is one of the core features of PTSD," explains de
Quervain. "The variant just predisposed to traumatic memory, but not to
PTSD."
Going forward, de Quervain said that neuroimaging studies are necessary
to determine where exactly the effect on the noradrenaline is taking
place in the brain. (Odds are that the amygdala, which is the seat of
emotional response to memory, has some involvement.) In addition, the
team will continue to look for other genes that may be related to
emotional memory. Once more novel genes are discovered, de Quervain
says, researchers can begin to test for relevance to anxiety disorders
like PTSD.
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Larry Scott --
