Resting-State Neural Signatures of Moral Injury: Associations With Rumination

Moral injury (MI) is a condition that may emerge following a violation of an individual's moral code. MI leads to significant functional impairment in many trauma-exposed civilians, with rumination proposed as a mechanism of action. Little is known about the neuropathophysiology of different MI dimensions, including MI related to transgressions caused by the self or others. We examined links between facets of MI, resting-state amplitude of low-frequency fluctuations (ALFF), and rumination in trauma-exposed civilians.

Sixty adults (ages 18-56 years; 51 female) completed measures of MI (Moral Injury Exposure and Symptom Scale for Civilians [MIESS-C]), rumination (Response Styles Questionnaire), and resting-state functional magnetic resonance imaging. Voxelwise linear regression on ALFF was performed with rumination and MIESS-C-derived self-, other-, and betrayal-related MI as regressors.

Betrayal-related MI associated with higher ALFF in the bilateral precuneus and left medial prefrontal cortex (mPFC). Other-related MI was associated with lower ALFF in the left dorsolateral PFC and insula (voxelwise p < .001, cluster false discovery rate-corrected p < .05). Rumination severity was positively associated with betrayal-related ALFF clusters in the bilateral precuneus (r = 0.32, p = .012) and left mPFC (r = 0.31, p = .017).

Results revealed distinct neural signatures of MI, with betrayal-related MI associated with greater ALFF in default mode network regions and this activation related to rumination severity. Other-related MI was linked to diminished activation in cognitive control and interoceptive network regions, which may reflect physiological withdrawal. These signatures are attractive candidate neuromodulatory targets.