For combat veterans suffering from post-traumatic stress disorder, 'fear circuitry' in the brain never rests

May 18, 2013

Chronic trauma can inflict lasting damage to brain regions associated with fear and anxiety. Previous imaging studies of people with post-traumatic stress disorder, or PTSD, have shown that these brain regions can over-or under-react in response to stressful tasks, such as recalling a traumatic event or reacting to a photo of a threatening face. Now, researchers at NYU School of Medicine have explored for the first time what happens in the brains of combat veterans with PTSD in the absence of external triggers.

Their results, published in Neuroscience Letters, and presented today at the annual meeting of the American Psychiatry Association in San Francisco, show that the effects of trauma persist in certain even when combat veterans are not engaged in cognitive or emotional tasks, and face no immediate external threats. The findings shed light on which areas of the brain provoke traumatic symptoms and represent a critical step toward better diagnostics and treatments for PTSD.

A chronic condition that develops after trauma, PTSD can plague victims with disturbing memories, flashbacks, nightmares and emotional instability. Among the 1.7 million men and women who have served in the wars in Iraq and Afghanistan, an estimated 20% have PTSD. Research shows that is higher in veterans with PTSD. Tragically, more soldiers committed suicide in 2012 than the number of soldiers who were killed in combat in Afghanistan that year.

"It is critical to have an objective test to confirm PTSD diagnosis as self reports can be unreliable," says co-author Charles Marmar, MD, the Lucius N. Littauer Professor of Psychiatry and chair of NYU Langone's Department of Psychiatry. Dr. Marmar, a nationally recognized expert on trauma and stress among veterans, heads The Steven and Alexandra Cohen Veterans Center for the Study of Post-Traumatic Stress and at NYU Langone Medical Center.

The study, led by Xiaodan Yan, a research fellow at NYU School of Medicine, examined "spontaneous" or "resting" brain activity in 104 veterans of combat from the Iraq and Afghanistan wars using functional MRI, which measures blood-oxygen levels in the brain. The researchers found that spontaneous brain activity in the amygdala, a key structure in the brain's "fear circuitry" that processes fearful and anxious emotions, was significantly higher in the 52 combat veterans with PTSD than in the 52 without PTSD. The PTSD group also showed elevated in the anterior insula, a brain region that regulates sensitivity to pain and negative emotions.

Moreover, the PTSD group had lower activity in the precuneus, a structure tucked between the 's two hemispheres that helps integrate information from the past and future, especially when the mind is wandering or disengaged from active thought. Decreased activity in the precuneus correlates with more severe "re-experiencing" symptoms—that is, when victims re-experience trauma over and over again through flashbacks, nightmares and frightening thoughts.

Key scientific contributors include researchers at NYU School of Medicine, the University of California at San Francisco, Mt. Sinai School of Medicine, and the Center for Imaging of Neurodegenerative Diseases at the VA Medical Center in San Francisco.

Explore further: PTSD linked to smaller brain area regulating fear response

Related Stories

PTSD linked to smaller brain area regulating fear response

November 5, 2012

Recent combat veterans who are diagnosed with post traumatic stress disorder have significantly smaller volume in an area of the brain critical for regulating fear and anxiety responses, according to research led by scientists ...

Why some soldiers develop PTSD while others don't

February 21, 2013

Pre-war vulnerability is just as important as combat-related trauma in predicting whether veterans' symptoms of post-traumatic stress disorder (PTSD) will be long-lasting, according to new research published in Clinical Psychological ...

Severely injured vets may need ongoing emotional care

April 11, 2013

(HealthDay)—U.S. veterans who suffered major limb injuries in combat showed little improvement with mental health problems such as depression, anxiety and post-traumatic stress disorder (PTSD) in the two years after receiving ...

Young vets with PTSD receive more CT scans

May 2, 2013

(HealthDay)—Computed tomography (CT) scans are significantly more commonly used in young veterans with posttraumatic stress disorder (PTSD) compared to young veterans without PTSD, according to research published in the ...

Recommended for you

Umbilical cells help eye's neurons connect

November 24, 2015

Cells isolated from human umbilical cord tissue have been shown to produce molecules that help retinal neurons from the eyes of rats grow, connect and survive, according to Duke University researchers working with Janssen ...

Brain connections predict how well you can pay attention

November 24, 2015

During a 1959 television appearance, Jack Kerouac was asked how long it took him to write his novel On The Road. His response – three weeks – amazed the interviewer and ignited an enduring myth that the book was composed ...

No cable spaghetti in the brain

November 24, 2015

Our brain is a mysterious machine. Billions of nerve cells are connected such that they store information as efficiently as books are stored in a well-organized library. To this date, many details remain unclear, for instance ...

Neurons encoding hand shapes identified in human brain

November 23, 2015

Neural prosthetic devices, which include small electrode arrays implanted in the brain, can allow paralyzed patients to control the movement of a robotic limb, whether that limb is attached to the individual or not. In May ...

Wireless sensor enables study of traumatic brain injury

November 23, 2015

A new system that uses a wireless implant has been shown to record for the first time how brain tissue deforms when subjected to the kind of shock that causes blast-induced trauma commonly seen in combat veterans.

Neuroscientists reveal how the brain can enhance connections

November 18, 2015

When the brain forms memories or learns a new task, it encodes the new information by tuning connections between neurons. MIT neuroscientists have discovered a novel mechanism that contributes to the strengthening of these ...


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.