Double Duty: Psychology Graduate Student Hopes Twins Hold Key to Understanding Post-Traumatic Stress Disorder
On most days, Michael VanElzakker can't help but see double.
This is what happens when your research subjects are twins.
VanElzakker, a GSAS psychology doctoral student and member of Professor Lisa
Shin's research group, is studying post-traumatic stress disorder (PTSD) among
identical twins, many of whom fought in the Vietnam War. PTSD—which afflicts as
many as 14 percent of returning Iraq War veterans (Source:" PTSD And Depression
Common In Returning Combat Soldiers," National Public Radio, 2010)—is
characterized by reoccurring memories of an emotionally traumatic event. A
person with PTSD may experience flashbacks of the traumatic event; have
uncontrollable, negative thoughts; avoid places or things associated with the
traumatic experience; and/or have difficulty controlling emotions.
VanElzakker's research focuses on the possibility of a biological link to PTSD,
that the neural wiring of certain individuals may make them a more likely
candidate to be afflicted with the disorder.
The twins in VanElzakker's study are broken up into two groups. The first group
consists of twins who fought in the Vietnam War
and got PTSD (their fellow twin was not involved in the conflict).
The second group consists of twins who fought in the Vietnam War and
did not get PTSD; like with the first
group, the fellow twin did not fight.
"We fly the twins in from all over the country
for two long days of brain scans and other types of testing," said VanElzakker.
"We collect a lot of
information about the structure and function of our participants' brains. For
example, we look at the chemical composition of their brains, the shape and size
of certain structures, and the thickness of nerve fibers within the brain. We
also look at how the brain responds functionally to different types of emotional
and cognitive experiences."
To gauge how the brain functions in the face
of these experiences, VanElzakker and his fellow researchers expose test subjects
in the lab to a
series of "fearful" and "non-fearful" faces.
When someone sees a "fearful face" or image, it can trigger a response in the
amygdala, the part of the brain which alerts an individual of a threat; it also
appears that this part of the brain stores emotional memories which can "hold" a
person's fear of, for example, spiders or dogs.
Even though VanElzakker's
project is in its early stages, there have been some interesting developments
"The data are still being
collected, and so all analyses are still quite preliminary," said
VanElzakker. "But from what the
data look like so far, one of the most striking things is that there really
seems to be a pre-existing neurocircuitry vulnerability to PTSD."
In other words, it appears that the twins in
the study may be predisposed to developing PTSD.
"The circuits involved in fear memory look very similar in the
veterans with PTSD and their twins," said VanElzakker. "We
hypothesized that the brains of veterans with PTSD would be
unique. But it's more like PTSD takes root in circuits that were
already there. We're hoping to find ‘biomarkers,' meaning that
we want to understand what PTSD looks like in the brain and
body. This information should result in more effective and
perhaps more personalized treatment strategies. Hopefully, the
twin study will help us better understand the root cause of