Why is it that some people develop symptoms of post-traumatic stress disorder (PTSD) after a stressful event, while others don't? Researchers from the Netherlands have found a possible answer. In a new study published in Nature, they found that higher brain activity in the anterior prefrontal cortex is associated with more resilience to the onset of post-traumatic stress.
The anterior prefrontal cortex is the part of the brain used to regulate emotional responses. Being able to control it over the amygdala's fight or flight' response is thought to help cope with life's stressors. Until now, however, it remained unclear how much prefrontal regulation of emotions contributed to resilience against developing symptoms of PTSD.
For the study, the researchers recruited 185 police officers. They used functional magnetic resonance imaging (fMRI) to monitor their brain activity during an approach-avoidance task- a computer task participants are shown images of happy and angry faces with the option to move towards or away from them with a joystick. Naturally, we tend to retreat from angry faces and approach happy faces. Being able to do the opposite requires one to override their automatic emotional response.
The researchers assessed the police officers once early in their training and then around a year and a half later. They also interviewed them to understand which were more affected by symptoms of PTSD, including poor sleep, avoidance of thoughts about the event, and negativity.
All in all, the researchers found that those with higher baseline activity in their prefrontal cortex tended to have fewer PTSD symptoms than those with lower activity at baseline following traumatic events. The researchers further noted that activity in the prefrontal cortex was more predictive of PTSD symptom development than self-reported and behavioral measures.
"In research into stress, the question is always whether differences between people, such as differences in brain activity, are a cause or a result of stress-related disorders such as PTSD." says lead author of the study, Reinoud Kaldewaij.
"With this study we have demonstrated the pre-existence of a stress resilience factor in the brain. That is the power of a longitudinal study, where you examine people both before and after a traumatic event. However, we still do not know whether this resilience factor against stress can be trained or not."