Altered dynamic functional connectivity in weakly-connected state in major depressive disorder

Area of Science:

• Neuroscience
• Psychiatry
• Medical Imaging

Background:

• Major depressive disorder (MDD) is linked to abnormal dynamic functional connectivity (FC) in the brain.
• Understanding if these FC abnormalities are state-dependent is crucial for MDD research.

Purpose of the Study:

• To investigate state-dependent abnormalities in dynamic functional connectivity (FC) in individuals with major depressive disorder (MDD).
• To explore the association between disease severity and the dynamics of aberrant FC.

Main Methods:

• Time-varying functional connectivity (FC) analysis was performed on resting-state functional magnetic resonance imaging (rs-fMRI) data.
• Data from 49 MDD patients and 54 healthy controls (HCs) were analyzed.
• Group differences in FC within identified connectivity states were examined.

Main Results:

• Two distinct connectivity states, weakly-connected and strongly-connected, were identified.
• MDD patients exhibited increased mean dwell time and decreased FC within and between subnetworks in the weakly-connected state compared to HCs.
• Reduced FC dynamics between the cognitive control network and default mode network predicted depression severity.

Conclusions:

• Functional connectivity alterations in MDD are predominantly observed in the weakly-connected state.
• These state-dependent FC changes may offer potential biomarkers for the clinical diagnosis of MDD.
• Findings offer novel insights into the neurophysiological mechanisms underlying MDD.