News | Magnetic Resonance Imaging (MRI) | December 18, 2015

Brain Regions of PTSD Patients Show Differences During Fear Responses

Brain Regions of PTSD Patients Show Differences During Fear Responses

Regions of the brain function differently among people with post-traumatic stress disorder, causing them to generalize non-threatening events as if they were the original trauma, according to new research from Duke Medicine and the Durham VA Medical Center.

Using functional MRI, the researchers detected unusual activity in several regions of the brain when people with PTSD were shown images that were only vaguely similar to the trauma underlying the disorder. The findings, reported in the Dec. 15, 2015, issue of the journal Translational Psychiatry, suggest that exposure-based PTSD treatment strategies might be improved by focusing on tangential triggers to the initial event.

“We know that PTSD patients tend to generalize their fear in response to cues that merely resemble the feared object but are still distinct from it,” said Rajendra A. Morey, M.D., an associate professor in the Department of Psychiatry and Behavioral Sciences at Duke and director of the Neuroimaging Lab at the Durham VA Medical Center. “This generalization process leads to a proliferation of symptoms over time as patients generalize to a variety of new triggers. Our research maps this in the brain, identifying the regions of the brain involved with these behavioral changes.”

Morey and colleagues enrolled 67 military veterans who had been deployed to conflict zones in Iraq or Afghanistan after Sept. 11, 2001, and who had been involved in traumatic events. Thirty-two were diagnosed with PTSD and 35 did not have the disorder.

All patients were showed a series of five facial images, depicting a range of emotions from neutral to frightened, while undergoing a functional MRI. The scans showed no dissimilarities between those with PTSD and those unaffected.

Outside the MRI, the participants were shown the images again and given a mild electrical shock when viewing the middle image – the face showing moderate fear.

The patients then underwent another MRI scan as they viewed all five faces. People with PTSD showed heightened brain activity when they saw the most fearful face and associated it with the electric shock, even though they had actually experienced shocks when the middle, less fearful face appeared. Brain activity was heightened for the non-PTSD group when participants saw the correctly associated middle face.

“The PTSD patients remembered incorrectly and generalized their anxiety to the image showing the most fearful expression,” Morey said. “This phenomenon was captured in MRI scans, showing where the PTSD group had heightened activity.

“The amygdala, which is an important region in responding to threat, did not show a bias in activation to any particular face,” Morey said. “But there was a definite bias of heightened activity in response to the most frightened expression in brain regions such as the fusiform gyrus, insula, primary visual cortex, locus coeruleus and thalamus.”

Morey said the visual cortex was significant because it is not only doing visual processing, but also assessing threats. He said the locus coeruleus is responsible for triggering the release of adrenaline during stress or serious threat.

These functional brain differences provide a neurobiological model for fear generalization in which PTSD symptoms are triggered by things that merely resemble the source of original trauma.

“People with posttraumatic stress disorder grow anxious based on reminders of past trauma, and generalize that fear to a variety of triggers that resemble the initial trauma,” Morey said. “Current fear conditioning therapies are limited by repeated use of the same cue to trigger the initial trauma, but they might be enhanced by including cues that resemble, but are not identical to, cues in the original trauma.”

In addition to Morey, study authors included Joseph E. Dunsmoor; Courtney C. Haswell; Vanessa M. Brown; Avani Vora; Jonathan Weiner; Daniel Stjepanovic;
Ryan Wagner III; Kevin S. LaBar; and the VA Mid-Atlantic MIRECC Workgroup.

This research received financial support from the Veterans Health Affairs and the National Institute of Neurological Disorders And Stroke of the National Institutes of Health.

For more information: www.dukemedicine.org

Related Content

Novel Technique May Significantly Reduce Breast Biopsies
News | Breast Biopsy Systems | January 17, 2019
A novel technique that uses mammography to determine the biological tissue composition of a tumor could help reduce...
Digital Mammography Increases Breast Cancer Detection
News | Mammography | January 16, 2019
The shift from film to digital mammography increased the detection of breast cancer by 14 percent overall in the United...
Artificial Intelligence Used in Clinical Practice to Measure Breast Density
News | Artificial Intelligence | January 15, 2019
An artificial intelligence (AI) algorithm measures breast density at the level of an experienced mammographer,...
Machine Learning Uncovers New Insights Into Human Brain Through fMRI
News | Neuro Imaging | January 11, 2019
An interdisciplinary research team led by scientists from the National University of Singapore (NUS) has successfully...
Mobile App Data Collection Shows Promise for Population Health Surveys
News | Population Health | January 10, 2019
Mobile app data collection can bring access to more potential clinical study participants, reduce clinical study...
Hypertension With Progressive Cerebral Small Vessel Disease Increases Cognitive Impairment Risk
News | Magnetic Resonance Imaging (MRI) | January 08, 2019
Patients with high blood pressure and progression of periventricular white matter hyperintensities showed signs of...
Artificial Intelligence Pinpoints Nine Different Abnormalities in Head Scans

A brain scan (left) showing an intraparenchymal hemorrhage in left frontal region and a scan (right) of a subarachnoid hemorrhage in the left parietal region. Both conditions were accurately detected by the Qure.ai tool. Image courtesy of Nature Medicine.

News | Artificial Intelligence | January 07, 2019
The rise in the use of computed tomography (CT) scans in U.S. emergency rooms has been a well-documented trend1 in...
Electronic Brachytherapy Effective in Long-Term Study of 1,000 Early-Stage Breast Cancers
News | Brachytherapy Systems, Women's Healthcare | January 07, 2019
Breast cancer recurrence rates of patients treated with intraoperative radiation therapy (IORT) using the Xoft Axxent...
Brachytherapy Alone Superior Treatment for Intermediate-Risk Prostate Cancer
News | Brachytherapy Systems | January 04, 2019
Patient-reported outcomes (PROs) indicated a significantly different clinician and patient-reported late toxicity...
Breast Cancer Patients Have Less Heart Damage With Heart Drug and Trastuzumab
News | Cardio-oncology | January 03, 2019
Breast cancer patients who take a heart drug at the same time as trastuzumab have less heart damage, according to a...