Nav: Home

Researchers look to unlock post-traumatic stress disorder puzzle

June 28, 2019

A team of Penn State and University of Puerto Rico School of Medicine researchers is attempting to answer a question that has long puzzled experts: Why do some individuals suffer post-traumatic stress disorder (PTSD) after experiencing trauma, and others do not?

The research, led by Nanyin Zhang, professor of biomedical engineering and Lloyd & Dorothy Foehr Huck Chair in Brain Imaging at Penn State, explores whether individual vulnerability to PTSD is due to pre-existing conditions or to a response to trauma exposure.

The team used the predator scent model of PTSD in rats and longitudinal design, which involves repeated observations of the same subject over a period of time. Using this methodology, they measured pre-trauma, brain-wide, neural circuit functional connectivity; behavioral responses to trauma exposure; release of corticosterone, a steroidal hormone produced in the cortex of adrenal glands; and post-trauma anxiety.

The results, reported in a recent issue of Nature Communications, found that rats that freeze and become motionless in response to predator scent exposure, correlate with functional connectivity in a set of neural circuits in the brain of these rats. Functional connectivity is the connectivity between different regions of the brain that share functional properties, and is measured via magnetic resonance imaging.

The researchers found that pre-existing neural circuit function can predispose animals to different fearful responses to threats.

"The data we gathered provides a framework of pre-existing circuit function in the brain that determines threat responses," Zhang said. "This may directly relate to PTSD-like behaviors."

Such a framework has a variety of potential benefits for further research into PTSD prevention and treatment.

"This research can help us understand core components of the vulnerability to stress-induced neuropsychiatric disorders," Zhang said. "These components can potentially serve as indicators to not only predict risk for developing anxiety disorders like PTSD but also assist in evaluating different stages of PTSD and possible recovery."

Using rats as test subjects helped overcome a major obstacle of investigating risk factors of PTSD in humans -- the difficulty of monitoring PTSD development from pre- through post- trauma in humans via exposure to well-controlled traumatic events. Studies on humans focus on populations already exposed to a variety of uncontrolled traumatic events and can lead to inconsistent results. Such barriers were overcome in the present study by using rats and applying longitudinal design with controlled traumatic stressors.

"The outcomes of the research can potentially be translated to human studies," Zhang said. "For instance, a biomarker predicting a vulnerability to stress-induced disorders will help determine the risk of assigning an individual to a highly stressful environment, such as combat."

One interesting aside in the study was a counterintuitive finding. Rats with lower freezing behavior showed more avoidance of the predator scent, a prolonged corticosterone response, and higher anxiety long after exposure to the scent.

"It is very likely that they froze less as they adopted different reactions to threats, such as fleeing," Zhang said.

Zhang said the next steps for the research team include identifying neuroimaging biomarkers that can predict an individual's response to threats and developing a process for determining the probability an individual will develop PTSD-like behaviors when exposed to trauma. The team will also explore methods to protect animals with high-risk factors from developing PTSD-like behaviors, such as through optogenetics, which is the use of light to control the activities of individual neurons in freely moving animals.
-end-
Along with Zhang, other researchers working on the study include David Dopfel, doctoral candidate in bioengineering; Pablo Perez, postdoctoral fellow in bioengineering; Alexander Verbitsky, graduate research assistant in engineering science and mechanics; and Yuncong Ma, doctoral candidate in bioengineering, all at Penn State; Héctor Bravo-Rivera, graduate student, University of Puerto Rico School of Medicine; and Gregory Quirk, professor of psychiatry, University of Puerto Rico School of Medicine.

Penn State

Related Brain Articles:

Scientists predict the areas of the brain to stimulate transitions between different brain states
Using a computer model of the brain, Gustavo Deco, director of the Center for Brain and Cognition, and Josephine Cruzat, a member of his team, together with a group of international collaborators, have developed an innovative method published in Proceedings of the National Academy of Sciences on Sept.
BRAIN Initiative tool may transform how scientists study brain structure and function
Researchers have developed a high-tech support system that can keep a large mammalian brain from rapidly decomposing in the hours after death, enabling study of certain molecular and cellular functions.
Wiring diagram of the brain provides a clearer picture of brain scan data
In a study published today in the journal BRAIN, neuroscientists led by Michael D.
Blue Brain Project releases first-ever digital 3D brain cell atlas
The Blue Brain Cell Atlas is like ''going from hand-drawn maps to Google Earth'' -- providing previously unavailable information on major cell types, numbers and positions in all 737 brain regions.
Landmark study reveals no benefit to costly and risky brain cooling after brain injury
A landmark study, led by Monash University researchers, has definitively found that the practice of cooling the body and brain in patients who have recently received a severe traumatic brain injury, has no impact on the patient's long-term outcome.
More Brain News and Brain Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Rethinking Anger
Anger is universal and complex: it can be quiet, festering, justified, vengeful, and destructive. This hour, TED speakers explore the many sides of anger, why we need it, and who's allowed to feel it. Guests include psychologists Ryan Martin and Russell Kolts, writer Soraya Chemaly, former talk radio host Lisa Fritsch, and business professor Dan Moshavi.
Now Playing: Science for the People

#537 Science Journalism, Hold the Hype
Everyone's seen a piece of science getting over-exaggerated in the media. Most people would be quick to blame journalists and big media for getting in wrong. In many cases, you'd be right. But there's other sources of hype in science journalism. and one of them can be found in the humble, and little-known press release. We're talking with Chris Chambers about doing science about science journalism, and where the hype creeps in. Related links: The association between exaggeration in health related science news and academic press releases: retrospective observational study Claims of causality in health news: a randomised trial This...