Structural covariance pattern abnormalities of insula in major depressive disorder: A CAN-BIND study report

Area of Science:

• Neuroscience
• Psychiatry
• Brain Imaging

Background:

• Major depressive disorder (MDD) is a complex condition with unclear etiopathogenesis.
• The insula's role in MDD is an area of active investigation.
• Understanding brain network alterations is crucial for diagnosing and treating MDD.

Purpose of the Study:

• To introduce and apply a novel gray matter volume (GMV) based structural covariance technique.
• To investigate structural brain network (SBN) coupling patterns of insular subregions in MDD patients.
• To compare these patterns between MDD patients and healthy controls.

Main Methods:

• A novel GMV-based structural covariance technique was employed.
• The unilateral insula was divided into three subregions: anterior, superior-posterior, and inferior-posterior.
• Structural coupling between insular subregions and whole-brain SBNs was analyzed in 157 MDD patients and 93 controls from the CAN-BIND cohort.

Main Results:

• MDD patients exhibited altered inter-network coupling in the right insula: increased with the default mode network (DMN) and decreased with the central executive network (CEN) in the anterior region; the reverse pattern was observed in the ventral-posterior region.
• Right ventral-posterior insular structural covariance negatively correlated with suicidal ideation in patients.
• Controls showed positive correlations between right ventral-posterior insular structural covariance and motor/psychomotor speed, which were absent in patients.

Conclusions:

• A novel technique for analyzing structural covariance coupling between large-scale SBNs was proposed.
• Findings provide evidence that MDD is a system-level disorder characterized by disrupted structural coupling between brain networks.
• Altered insular connectivity patterns may serve as potential biomarkers for MDD and its associated symptoms.