Understanding how post-traumatic stress disorder (PTSD) impacts the brain is an important step to developing effective treatments for the many armed forces veterans who return from deployment with PTSD. A new study from the Hospital for Sick Children in Canada, in partnership with Canadian Armed Forces, finds that soldiers with PTSD have heightened brain reactions to threatening expressions than soldiers without PTSD. The study finds that over-connected brain circuitry in key areas is to blame. The findings are useful because they may lead to a better assessment method for PTSD, which can be difficult to diagnose.
The research team monitored the brain activity of 20 Canadian Armed Forces soldiers with PTSD and 25 without PTSD using magnetoencephalography (MEG) while the participants viewed images of facial expressions. The researchers then compared brain activity in the amygdala (which regulates the fight-or-flight response) and the ventral medial prefrontal cortex (which inhibits the fear response) between the two groups of soldiers.
Soldiers with and without PTSD demonstrated similar behavioral reactions when viewing angry and happy expressions, but their brain responses told a different story. When viewing angry faces, the soldiers with PTSD exhibited over-connectivity from the amygdala and the ventral medial prefrontal cortex to other brain regions. This indicates that the heightened perception of threat in PTSD may be caused by over-connectivity between these fear-regulating brain areas. The data revealed typical brain functioning when the soldiers with PTSD viewed happy expressions.
“We were surprised to find that all key brain circuits were over-connected in PTSD. This may be why emotional responses are so immediate and automatic, and why threatening faces are such a trigger. These findings emphasize the challenges of living with PTSD and treating PTSD,” stated lead study author Dr. Benjamin Dunkley.
Dr. Dunkley also states that the findings may lead to improved assessments for PTSD. This could result in a better method for determining when soldiers are ready to return to deployment.
This research is published in the journal Heliyon.