Characterizing multiscale modular structures in medication-free obsessive-compulsive disorder patients with no...

Area of Science:

• Neuroscience
• Connectomics
• Systems Neuroscience

Background:

• Brain networks possess modular structures optimizing wiring cost and information transmission.
• Altered modularity in brain networks is implicated in obsessive-compulsive disorder (OCD).
• Previous OCD connectomic studies often examined modularity at a single scale.

Purpose of the Study:

• To comprehensively investigate modular architecture alterations in the functional connectome of OCD patients across global, meso, and local scales.
• To explore the relationship between brain network modularity changes and OCD symptom severity.

Main Methods:

• Recruited 92 OCD patients and 90 healthy controls for voxelwise functional connectome analysis.
• Assessed modular architecture at global (modularity), meso (segregation, within/between-module connections), and local (participation coefficients) levels.
• Correlated modular structure metrics with OCD clinical symptom scores.

Main Results:

• No significant difference in global modularity between OCD patients and controls.
• OCD patients exhibited reduced modular segregation in primary (visual, sensorimotor) and high-order (dorsal attention, frontoparietal) networks, linked to increased between-module connections.
• OCD patients showed altered participation coefficients in specific brain regions, including the occipital, frontal, and temporal lobes, with some regions showing higher and others lower PC values.

Conclusions:

• Functional network dysfunction in OCD involves alterations across multiple modularity scales.
• Increased between-module connectivity and altered participation coefficients in specific regions contribute to disrupted modular segregation in OCD.
• Observed changes in brain network modularity are associated with OCD pathophysiology and clinical symptoms.