Dynamic modular-level alterations of structural-functional coupling in clinically isolated syndrome.

Area of Science:

• Neuroscience
• Radiology
• Neurology

Background:

• Multiple sclerosis (MS) involves abnormalities in brain structure and function.
• The relationship between evolving structural and functional connectivity in MS is not well understood.
• Structural-functional coupling may detect brain alterations more sensitively than individual modalities.

Purpose of the Study:

• To investigate the longitudinal changes in structural-functional coupling in the first year after clinically isolated syndrome (CIS).
• To explore global and modular alterations in connectivity over time.
• To test the hypothesis that MS causes decoupling between functional and structural connectivity.

Main Methods:

• Prospective study of 41 patients with CIS and 19 healthy controls over 1 year.
• Resting-state functional MRI and diffusion tensor imaging at baseline and follow-up.
• Graph theory analysis and neuropsychological assessments.

Main Results:

• Patients with CIS showed baseline structural reorganization (increased clustering coefficient) and modular alterations.
• After 1 year, both structural and functional reorganization occurred, with abnormal modular connectivity and increased functional betweenness centrality.
• Structural-functional decoupling was observed in salience, visual, and somatomotor networks, despite preserved cognitive performance.

Conclusions:

• Structural damage precedes functional reorganization in the first year of MS following CIS.
• The observed structural-functional decoupling suggests compensatory mechanisms are active.
• Functional reorganization may occur via indirect anatomical pathways in early MS.