Unlocking the Secrets of PTSD: Is Amygdala Hyperresponsivity a Familial Vulnerability for PTSD?
A research team from Tufts University, Massachusetts, have likely found a marker that indicates vulnerability to post-traumatic stress disorder (PTSD).
They discovered that heightened activation in the amygdala in response to seeing surprised and neutral facial expressions appears to be tied to developing PTSD.
Previous research has found abnormalities in brain activation in individuals with PTSD, including hyperresponsivity in the amygdala and hyporesponsivity in the ventral portions of the medial prefrontal cortex. This phenotype is described as the emotional undermodulation phenotype of PTSD.
It is unclear if these abnormalities generalise to more ambiguous stimuli and whether they reflect familial vulnerabilities, trauma exposure, or acquired characteristics of PTSD.
This study used functional magnetic resonance imaging (fMRI) to measure brain responses to emotionally ambiguous stimuli (surprised facial expressions) in identical twin pairs discordant for trauma exposure.
The results showed that amygdala activation to surprised and neutral facial expressions was greater in individuals with PTSD and their trauma-unexposed identical co-twins without PTSD, compared to control twin pairs.
In contrast, medial frontal gyrus (MFG) activation to surprised facial expressions was diminished in the PTSD group relative to the other three groups.
The study suggests that amygdala hyperresponsivity to emotionally ambiguous facial expressions may be a familial vulnerability factor that increases the likelihood of developing PTSD after experiencing a traumatic event, while MFG hyporesponsivity may be an acquired characteristic of the disorder.
While this discovery is a significant step towards a deeper understanding of PTSD and the role that the brain plays in its development, further research with larger and more diverse participant samples is needed to confirm these findings. By better understanding the mechanisms underlying PTSD, we can work towards better prevention and management of this condition.
Hinojosa, C. A., VanElzakker, M. B., Hughes, K. C., Offringa, R., Sangermano, L. M., Spaulding, I. G., … & Shin, L. M. (2022). Exaggerated amygdala activation to ambiguous facial expressions is a familial vulnerability factor for posttraumatic stress disorder. Journal of Psychiatric Research, 156, 451-459.