Abnormal Static and Dynamic Local Functional Connectivity in First-Episode Schizophrenia: A Resting-State fMRI Study

Area of Science:

• Neuroscience
• Psychiatry
• Medical Imaging

Background:

• Schizophrenia involves global functional connectivity (FC) disturbances.
• Local FC dynamics in never-treated first episode schizophrenia (FES) are poorly understood.
• Dynamic Regional Phase Synchrony (DRePS) offers a novel method for local FC analysis.

Purpose of the Study:

• To comprehensively examine static and dynamic local FC alterations in FES patients.
• To compare DRePS-derived static local FC with traditional regional homogeneity (ReHo) methods.
• To explore the association between local FC metrics and clinical/cognitive characteristics in FES.

Main Methods:

• Resting-state fMRI was used in FES patients (N=74) and healthy controls (HCs, N=41).
• Dynamic Regional Phase Synchrony (DRePS) was applied for local FC analysis.
• Static local FC metrics were compared with Kendall's coefficient of concordance (KCC-ReHo) and frequency coherence (Cohe-ReHo).

Main Results:

• FES patients showed increased static local FC in specific brain regions (e.g., temporal gyri, hippocampus, basal ganglia) compared to HCs.
• No significant differences in dynamic local FC metrics were found between FES and HCs.
• A combination of static and dynamic FC features significantly predicted Global Assessment of Functioning and Brief Visuospatial Memory Test-Revised scores.
• Including DRePS' zero crossing ratio improved classification accuracy for schizophrenia detection.

Conclusions:

• Schizophrenia is associated with altered static local functional connectivity.
• Dynamic local FC metrics alone did not differentiate FES from HCs.
• DRePS, particularly its dynamic metrics, shows potential as a diagnostic biomarker for schizophrenia when combined with static measures.