Scientists report link between traumatic brain injury, post-traumatic stress disorder

February 15, 2012 By Stuart Wolpert, University of California Los Angeles

(Medical Xpress) -- UCLA life scientists and their colleagues have provided the first evidence of a causal link between traumatic brain injury and an increased susceptibility to post-traumatic stress disorder.

Their new study, published Feb. 15 in the in the journal Biological Psychology, also suggests that people who suffer even a mild are more likely to develop an anxiety disorder and should take precautions to avoid stressful situations for at least some period of time.

The motivation behind the study, which was conducted in rats, was the observed correlation of traumatic , or TBI, and PTSD, particularly in military veterans returning from service overseas, said Michael Fanselow, a UCLA professor of psychology and the senior author of the study. 

The reasons for this correlation are unknown. It could be simply that the events that cause brain injury are also very frightening and that the link between TBI and PTSD could be merely incidental. Fanselow and his colleagues, however, hypothesized that the two "could be linked in a more mechanistic way."

Using procedures to separate the physical and emotional traumas, the scientists trained the rats using " conditioning" techniques two days after they experienced a concussive brain trauma — ensuring the brain injury and the experience of fear occurred on different days.

"We found that the rats with the earlier TBI acquired more fear than control rats (without TBI)," said Fanselow, a member of UCLA's Brain Research Institute. "Something about the brain injury rendered them more susceptible to acquiring an inappropriately strong fear. It was as if the injury primed the brain for learning to be afraid."

To learn why this occurred, the researchers analyzed a small piece of brain tissue, the amygdala, which is the brain's critical hub for fear learning.

"We found that there are significantly more receptors for excitatory neurotransmitters that promote learning," said Maxine Reger, a UCLA graduate student of psychology in Fanselow's laboratory and the lead author of the study.

"This finding suggests that brain injury leaves the amygdala in a more excitable state that readies it for acquiring potent fear," Fanselow said.

The research was funded by the National Institutes of Health, the U.S. Department of Defense and the UCLA Brain Injury Research Center.

Co-authors of the study were David Hovda, a professor of neurosurgery and of molecular and medical pharmacology at the David Geffen School of Medicine at UCLA and director of the UCLA Brain Injury Research Center; Andrew Poulos, a postdoctoral fellow in Fanselow's laboratory; Floyd Buen, a former graduate student in Hovda's laboratory; and Christopher Giza, an associate professor of neurosurgery at the Geffen School of Medicine.

The research was a collaboration between Fanselow's laboratory, which studies neural mechanisms of anxiety disorders, and Hovda's laboratory, which investigates brain injury.

"One of UCLA's great strengths is the spirit of collaboration that allows scientists from very different departments to combine their very different expertises to answer important but difficult questions," Fanselow said.

Explore further: Traumatic brain injury increases risk of Parkinson's disease, researchers say

More information: The article is "Concussive Brain Injury Enhances Fear Learning and Excitatory Processes in the Amygdala" by Maxine L. Reger, Andrew M. Poulos, Floyd Buen, Christopher C. Giza, David A. Hovda, and Michael S. Fanselow (doi:10.1016/j.biopsych.2011.11.007). The article appears in Biological Psychiatry, Volume 71, Issue 4 (February 15, 2012)

Related Stories

Traumatic brain injury increases risk of Parkinson's disease, researchers say

August 22, 2011
(Medical Xpress) -- Traumatic brain injury has entered the public's consciousness as the silent, signature wound brought back by many of our military warriors from Iraq and Afghanistan. But such injuries don't only happen ...

Risk factors predictive of psychiatric symptoms after traumatic brain injury

July 12, 2011
A history of psychiatric illness such as depression or anxiety before a traumatic brain injury (TBI), together with other risk factors, are strongly predictive of post-TBI psychiatric disorders, according to an article published ...

Recommended for you

Study of learning and memory problems in OCD helps young people unlock potential at school

January 22, 2018
Adolescents with obsessive-compulsive disorder (OCD) have widespread learning and memory problems, according to research published today. The findings have already been used to assist adolescents with OCD obtain the help ...

Intensive behavior therapy no better than conventional support in treating teenagers with antisocial behavior

January 19, 2018
Research led by UCL has found that intensive and costly multisystemic therapy is no better than conventional therapy in treating teenagers with moderate to severe antisocial behaviour.

Babies' babbling betters brains, language

January 18, 2018
Babies are adept at getting what they need - including an education. New research shows that babies organize mothers' verbal responses, which promotes more effective language instruction, and infant babbling is the key.

College branding makes beer more salient to underage students

January 18, 2018
In recent years, major beer companies have tried to capitalize on the salience of students' university affiliations, unveiling marketing campaigns and products—such as "fan cans," store displays, and billboard ads—that ...

Inherited IQ can increase in early childhood

January 18, 2018
When it comes to intelligence, environment and education matter – more than we think.

Modulating molecules: Study shows oxytocin helps the brain to modulate social signals

January 17, 2018
Between sights, sounds, smells and other senses, the brain is flooded with stimuli on a moment-to-moment basis. How can it sort through the flood of information to decide what is important and what can be relegated to the ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.