Topologically state-independent and dependent functional connectivity patterns in current and remitted depression.

Area of Science:

• Neuroscience
• Psychiatry
• Network Science

Background:

• Major depressive disorder (MDD) is a complex mental health condition with unclear pathophysiology.
• Identifying neural biomarkers can aid in understanding MDD and developing effective treatments.

Purpose of the Study:

• To investigate state-independent and state-dependent topological alterations in brain functional networks of individuals with MDD.
• To identify potential neural biomarkers for MDD using resting-state functional magnetic resonance imaging (fMRI).

Main Methods:

• Acquired resting-state fMRI data from 59 unmedicated current MDD (cMDD) patients, 48 remitted MDD (rMDD) patients, and 60 healthy controls (HCs).
• Applied graph theory to analyze whole-brain functional network topology at global and nodal levels.

Main Results:

• Both cMDD and rMDD groups exhibited decreased global normalized clustering coefficients compared to HCs.
• Decreased nodal centrality was observed in both patient groups, particularly in mood-regulation brain regions (dorsolateral prefrontal cortex, posterior parietal cortex, posterior cingulate cortex).
• The rMDD group showed higher nodal centrality in the right parahippocampal gyrus compared to the cMDD group.

Conclusions:

• Deficits in whole-brain and mood-regulation brain region topological organization are state-independent biomarkers in both current and remitted MDD.
• These findings suggest persistent neural network alterations in MDD, regardless of symptom state.