Civilian Moral Injury and Amygdala Functional Connectivity During Attention to Threat

Abstract

Background: Moral injury references emotional and spiritual/existential suffering that may emerge following psychological trauma. Despite being linked to adverse mental health outcomes, little is known about the neurophysiological mechanisms of this phenomenon. In this study, we examined neural correlates of moral injury exposure and distress using the Moral Injury Exposure and Symptom Scale for Civilians. We also examined potential moderation of these effects by race (Black vs. White individuals) given the likely intersection of race-related stress with moral injury.

Methods: Forty-eight adults ages 18 to 65 years (mean age = 30.56, SD = 11.93) completed the Moral Injury Exposure and Symptom Scale for Civilians and an affective attentional control measure, the affective Stroop task (AS), during functional magnetic resonance imaging; the AS includes presentation of threat-relevant and neutral distractor stimuli. Voxelwise functional connectivity of the bilateral amygdala was examined in response to threat-relevant versus neutral AS distractor trials.

Results: Functional connectivity between the right amygdala and left postcentral gyrus/primary somatosensory cortex was positively correlated with the Moral Injury Exposure and Symptom Scale for Civilians exposure score (voxelwise p < .001, cluster false discovery rate-corrected p < .05) in response to threat versus neutral AS distractor trials. Follow-up analyses revealed significant effects of race; Black but not White participants demonstrated this significant pattern of amygdala-left somatosensory cortex connectivity.

Conclusions: Increased exposure to potentially morally injurious events may lead to emotion-somatosensory pathway disruptions during attention to threat-relevant stimuli. These effects may be most potent for individuals who have experienced multilayered exposure to morally injurious events, including racial trauma. Moral injury appears to have a distinct neurobiological signature that involves abnormalities in connectivity of emotion-somatosensory paths, which may be amplified by race-related stress.

Keywords: Attention; Civilians; Functional connectivity; Moral injury; Trauma.