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STUDY PROBES ROOTS OF FEARFUL MEMORIES --
New research is helping scientists understand
why
frightening, traumatic memories, which can help
cause
PTSD, go so deep and linger so long in the
human brain.
For more on
norepinephrine, use the VA Watchdog search
engine...click here...
http://www.yourvabenefits.org/ses
search.php?q=Norepinephrine&op=and
For more on PTSD, use the VA Watchdog search
engine...click here...
http://www.yourvabenefits.org/ses
search.php?q=ptsd&op=and
Story here...
http://www.forbes.com/
forbeslife/health/feeds/hscout/20
07/08/22/hscout607525.html
Story below:
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Study Probes Roots of Fearful Memories
WEDNESDAY, (HealthDay News) -- New research is helping scientists
understand why frightening, traumatic memories go so deep and linger so
long in the human brain.
A study in rats shows that a powerful neurochemical called
norepinephrine is released to help the brain deal with trauma -- but it
also "imprints" an emotional fear tagged to the memory of that event.
These emotionally loaded memories could help cause post-traumatic stress
disorder (PTSD), said a team at Harvard University. But the findings may
also provide a target for treatment, they added.
"Norepinephrine is released in a part of the brain called the amygdala,
which is associated with emotional conditions, particularly in bad
situations," said lead researcher Vadim Bolshakov, director of the
Cellular Neurobiology Laboratory at Harvard-affiliated McLean Hospital,
in Belmont, Mass.
In addition, norepinephrine -- also called noradrenalin -- makes
memories last longer, Bolshakov said. "There is some evidence that
norepinephrine is involved in the transition from short-term memory to
long-term memory," he said.
According to Bolshakov, experiments with rats suggest that when a
traumatic event occurs, a surge of norepinephrine occurs in the brain.
In the new study, Bolshakov's team used the rodents' fear of certain
sounds to uncover the mechanisms driving fearful behavior. The animals
learned to associate a sound with a mild foot shock.
The researchers looked at tissue slices from the amygdala region of the
rat's brain that were then infused with norepinephrine. They observed
how norepinephrine increased fear-learning through brain cell pathways
linked to fear conditioning, Bolshakov said.
"We could see how the brain cells 'talked' to each other," Bolshakov
said. "This could be a model of PTSD," because norepinephrine increased
long-term memory in emotionally charged situations, he said.
PTSD and other mental conditions, such as generalized anxiety disorder,
are associated with fear conditioning. The finding could lead to a
better understanding of these conditions, too -- as well as better
treatments, Bolshakov said.
He believes that blocking norepinephrine production as soon as possible
after a traumatic event might prevent PTSD, because these events would
be blocked from becoming long-term memories.
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Larry Scott --
