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Published on: August 11, 2015
Disrupted resting-state amygdala connectivity dynamics in major depressive disorder with suicidal ideation:
Chengwen Liu1, Shulin Fang2, Chang Cheng3
1Cognition and Human Behavior Key Laboratory of Hunan Province, Department of Psychology, Hunan Normal University, Changsha, China; Medical Psychological Center, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China.
Background:
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.
Methods:
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.
Results:
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.
Conclusion:
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.
Trial Registration:
The registration number is ChiCTR2000031931 and date of registration is April 15th 2020.
Insights
Major depressive disorder (MDD) with suicidal ideation (SI) shows altered brain network dynamics, particularly in the amygdala. These disruptions in functional connectivity may underlie emotional dysregulation and increased suicide risk.
Area of Science:
- Neuroscience
- Psychiatry
- Medical Imaging
Background:
- Major depressive disorder (MDD) frequently co-occurs with suicidal ideation (SI).
- Functional disruptions in emotion-regulating brain regions, like the amygdala, are implicated in MDD with SI.
- The temporal dynamics of amygdala-based functional connectivity in MDD patients with SI are not well understood.
Purpose of the Study:
- To investigate the temporal dynamics of amygdala-based functional connectivity in first-episode MDD patients with and without suicidal ideation (SI).
- To identify distinct network states and their dynamic metrics related to clinical characteristics.
- To assess the potential of these dynamic metrics for classifying individuals based on SI.
Main Methods:
- Resting-state functional magnetic resonance imaging (fMRI) was performed on first-episode MDD patients with SI (n=53), without SI (NSI, n=27), and healthy controls (HCs, n=58).
- Co-activation pattern (CAP) analysis was used to characterize amygdala connectivity dynamics and identify five distinct network states.
- Dynamic metrics of these network states were analyzed, and support vector machine (SVM) classification was applied.
Main Results:
- Both SI and NSI groups exhibited increased dominance of the affective network (AN) co-activated with the amygdala compared to HCs, correlating positively with anxiety.
- The SI group showed decreased occurrence and resilience of a transient network state involving the default mode network (DMN) and reward network (RN), negatively correlating with SI severity.
- Dynamic CAP metrics effectively distinguished SI individuals from NSI and HC groups via SVM classification.
Conclusions:
- MDD with SI is characterized by heightened temporal instability of the AN, linked to excessive anxious mood.
- Diminished amygdala-DMN-RN coupling in SI patients suggests impaired self-referential and reward processing.
- Aberrant amygdala-based network dynamics may represent neurobiological substrates for emotional dysregulation and elevated suicide risk in MDD.
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