Decreased Resting-State Interhemispheric Functional Connectivity in Medication-Free Obsessive-Compulsive Disorder

Area of Science:

• Neuroscience
• Psychiatry
• Radiology

Background:

• Cortico-striato-thalamo-cortical (CSTC) circuits are implicated in obsessive-compulsive disorder (OCD) pathophysiology.
• Reduced homotopic connectivity within CSTC circuits is a potential factor in OCD.
• Interhemispheric functional connectivity (FC) at rest in OCD remains underexplored.

Purpose of the Study:

• To investigate interhemispheric coordination at rest in individuals with OCD.
• To utilize the voxel-mirrored homotopic connectivity (VMHC) method to analyze resting-state fMRI data in OCD patients.

Main Methods:

• Resting-state functional magnetic resonance imaging (fMRI) was performed on 40 medication-free patients with OCD and 38 healthy controls (HCs).
• Voxel-mirrored homotopic connectivity (VMHC) analysis was employed to assess interhemispheric FC.
• Support vector machine (SVM) was used to differentiate between OCD patients and HCs based on VMHC values.

Main Results:

• Patients with OCD exhibited significantly lower VMHC values in the orbitofrontal cortex, thalamus, middle occipital gyrus, and precentral and postcentral gyri compared to HCs.
• VMHC values in the thalamus and postcentral gyrus were identified as optimal discriminators between OCD patients and HCs.
• These findings indicate widespread alterations in interhemispheric FC in OCD.

Conclusions:

• Decreased interhemispheric FC within and beyond CSTC circuits contributes to the pathophysiology of OCD.
• The study provides neuroimaging evidence supporting the role of altered brain connectivity in OCD.
• VMHC analysis is a valuable tool for understanding interhemispheric dysfunction in psychiatric disorders.