A generalized disruption in the brain’s memory control system may explain why people with post-traumatic stress disorder (PTSD) are unable to suppress unwanted memories, a study published in the journal Science suggests.
“This disruption could constitute a central factor in the persistence of traumatic memories,” researchers wrote, “undercutting the ability to deploy the necessary coping resources that maintain healthy memory.”
The findings stem from functional magnetic resonance imaging (fMRI) scans of 175 individuals, including 102 people exposed to the 2015 Paris terrorist attacks—55 of whom had PTSD symptoms. In a laboratory setting, researchers implemented neutral and inoffensive memories paired with a reminder cue. Brain scans subsequently measured how the dorsolateral prefrontal cortex, a core of the brain’s control system, regulated and suppressed memory activity during intrusive memories.
While participants without PTSD demonstrated a significant reduction of the functional coupling between control and memory systems during attempts to stop the emergence of intrusive memories, participants with PTSD had a near-absence of decreased connectivity, researchers found.
In participants without PTSD, the suppression of intrusive memories arose from regulation of the right anterior dorsolateral prefrontal cortex, which worked to reduce the response of memory processes.
“Our study suggests that the general mental operations typically engaged to banish and suppress the intrusive expression of unwanted memories might contribute to positive adaptation in the aftermath of a traumatic event,” researchers wrote, “paving the way for new treatments.”