Dinámica alterada de la conectividad de la amígdala en estado de reposo en el trastorno depresivo mayor con ideación...

Major depressive disorder (MDD) is frequently accompanied by suicidal ideation (SI), which has been linked to functional disruptions in brain regions involved in emotion regulation, including the key amygdala. However, the temporal dynamics of amygdala-based functional connectivity in MDD patients with SI remain unclear.

First-episode MDD patients with SI (n = 53), without SI (NSI, n = 27), and healthy controls (HCs, n = 58) who underwent resting-state functional magnetic resonance imaging were included. Co-activation pattern (CAP) analysis was employed to characterize amygdala connectivity dynamics. Five distinct network states were identified and corresponding dynamic metrics were analyzed with respect to clinical characteristics, and support vector machine (SVM) classification was applied to classify individuals based on aberrant CAP features.

Both SI and NSI groups showed increased dominance of the affective network (AN) co-activated with the amygdala compared to HCs, with a positive correlation to anxiety symptoms. Notably, SI group exhibited decreased occurrence rate and resilience of a transient network state, predominantly involving the default mode network (DMN) and reward network (RN), which was negatively correlated with SI severity. SVM classification achieved robust performance in distinguishing SI individuals from NSI and HC based on dynamic CAP metrics.

These findings highlight heightened temporal instability of the AN and associated excessive anxious mood in MDD, while the diminished dominance of the amygdala-DMN-RN coupling indicates impairments in self-referential and reward processing in MDD patients with SI. Overall, disruptions in amygdala-based network dynamics may implicate neurobiological substrates underlying emotional dysregulation and elevated suicide risk in MDD.

The registration number is ChiCTR2000031931 and date of registration is April 15th 2020.