Structure-function coupling and hierarchy-specific antidepressant response in major depressive disorder.

Area of Science:

• Neuroscience
• Neuroimaging
• Psychiatry

Background:

• Major depressive disorder (MDD) is associated with altered brain networks, but structure-function coupling (SFC) findings are inconsistent.
• The brain's functional hierarchy may explain variations in SFC and MDD pathology.
• Investigating SFC across functional levels is crucial for understanding MDD and treatment response.

Purpose of the Study:

• To investigate alterations in structure-function couplings (SFC) in major depressive disorder (MDD) patients compared to healthy controls (HC).
• To examine the relationship between SFC and antidepressant response in MDD.
• To analyze SFC changes from a functional hierarchical perspective.

Main Methods:

• Compared regional SFC in MDD patients (n=258) and HC (n=99) using resting-state fMRI and diffusion tensor imaging.
• Assessed SFC differences between antidepressant non-responders (n=55) and responders (n=68).
• Ranked regions by principal gradient values to evaluate hierarchy-specific SFC patterns.

Main Results:

• MDD patients showed increased SFC in unimodal regions (low gradient) and decreased SFC in transmodal regions (high gradient) versus HC.
• Antidepressant responders exhibited higher SFC in unimodal regions and lower SFC in attentional networks.
• Significant differences in SFC were observed across the functional hierarchy (p < 0.001).

Conclusions:

• MDD pathology involves opposing SFC alterations in low-level unimodal and high-level transmodal networks.
• SFC variations across the functional hierarchy highlight spatial heterogeneity in MDD.
• Hierarchy-specific antidepressant effects offer potential for predicting treatment outcomes in MDD.