Brain's Gray Cells Appear To Be Changed By Trauma Of Major Events Like 9/11 Atta

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http://www.sciencedaily.com/releases/2008/06/080603184256.htm

 

ScienceDaily (Jun. 4, 2008) — Healthy adults who were close to the

World Trade Center during the terrorist attacks on Sept. 11, 2001,

have less gray matter in key emotion centers of their brains compared

with people who were more than 200 miles away, finds a new Cornell study.

 

" This suggests that really bad experiences may have lasting effects on

the brain, even in healthy people, " said Barbara Ganzel, the study's

lead researcher and postdoctoral fellow at Cornell's College of Human

Ecology.

 

The study -- one of the first to look at the effects of trauma on the

brains of healthy adults -- is published in the April issue of

Neurolmage. It follows a Cornell study by the same authors that found

people living near the World Trade Center on 9/11 have brains that are

more reactive to such emotional stimuli as photographs of fearful

faces. Combined, the two studies provide an emerging picture of what

happens in the brains of healthy people who experience a traumatic event.

 

The smaller volume of gray matter -- composed largely of cells and

capillary blood vessels -- that Ganzel found were in areas that

process emotion and may be, Ganzel suggests, the brain's normal

response to trauma. The subjects in the study did not suffer from any

mental or physical health disorders. Gray matter, a major component of

the nervous system, is composed of the neuron cell bodies that process

information in the brain.

 

About half of Americans experience a trauma in their lifetime, and

scientists know a lot about the effects of trauma on the brains of

people with post-traumatic stress disorder (PTSD), but not about

people without clinical disorders. And most people, Ganzel said, who

experience a trauma don't get PTSD.

 

Key brain areas that are smaller are also more responsive to threat,

said Ganzel, suggesting that these changes may be a helpful response

to living in an uncertain environment.

 

" We have known for a long time that trauma exposure can lead to

subsequent vulnerability to mental health disorders years after the

trauma, " Ganzel added. " This research gives us clues about the biology

underlying that vulnerability. "

 

The researchers used two types of magnetic resonance imaging to scan

the brains of 18 people who were within 1.5 miles of the World Trade

Center on Sept. 11 and compared them to scans of 18 people who lived

at least 200 miles away at the time. One type showed the gray matter

volume, and the other showed the brain's response to emotional stimuli

(pictures of fearful and calm faces). Those who were close to the

disaster on Sept. 11 showed more emotional reactivity in the amygdala,

a brain area that detects the presence of threatening information.

 

Combining the brain data revealed that those who were near the World

Trade Center had smaller, more reactive amygdalas, and this, in turn,

was related to how anxious they were years later. Several other brain

regions associated with emotion processing were also smaller in those

who were close to the disaster.

 

The researchers also found that study subjects who had experienced

other types of trauma (violent crimes, sudden death of a loved one)

showed a similar reduction in gray matter and similar response to

emotional faces and anxiety.

 

" This suggests that the differences we see in the brain and behavior

of people who were near the Sept. 11 disaster are not specific to that

one event, " Ganzel said. " And it turns out there is a very similar

pattern of gray matter volume loss with normal aging, which raises the

question of what role trauma plays in the aging brain. "

 

Co-authors include Elise Temple of Dartmouth College, Cornell graduate

student Pilyoung Kim, and Gary Glover of Stanford University.

Adapted from materials provided by Cornell University. Original

article written by Sheri Hall.

 

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Not totally convinced about the interpretation, but I'm open to it. I

tend to think that people go through " transmarginal inhibition " :

 

" Transmarginal Inhibition, or TMI, is an organism's response to

overwhelming stimuli. Ironically, the popular acronym TMI means too

much information, which can be a common factor of transmarginal

inhibition in today's culture.[...] "

 

Read more at

http://laura-knight-jadczyk.blogspot.com/2007/07/transmarginal-inhibition-or-bat\

tle-for.html

 

best,

navegante