Are amygdala and insula consistently hyperresponsive to aversive stimuli in PTSD? Comment on Bastos et al. 2022

Abstract

Background

A recurring theme in fMRI studies is the inconsistent findings in amygdala and insula hyperreactivity among patients with PTSD vs. trauma-exposed controls. This study reanalyzed data from Bastos et al. (2022) investigating group effects to aversive stimuli in those regions.

Methods

Patients with PTSD (n = 20) and trauma-exposed controls (n = 23) briefly viewed neutral and mutilation pictures. Amygdala and insula ROIs were analyzed for valence and group effects. Subsequently, regressor duration was extended to determine whether a longer regressor would capture a lasting valence effect beyond picture presentation.

Results

Significant main effects of valence were observed in the amygdala and insula ROIs, for both regressor durations. In both regions there were no significant main effects for group. Further no interactions between valence and group were found, indicating lack of consistent hyperresponsivity in patients with PTSD.

Conclusions

Our results help to challenge hyperreactivity as a proxy of PTSD. In fact, multiple traumatic experiences and/or childhood maltreatment were shown to be associated with hyporeactivity in PTSD. If this is not taken into consideration, the average pattern of reactivity recorded from a mixed sample with both hypo and hyper responders can be indistinguishable from controls.