Abnormal functional connectivity density in patients with obsessive-compulsive disorder.

Area of Science:

• Neuroscience
• Psychiatry
• Radiology

Background:

• Obsessive-compulsive disorder (OCD) is a debilitating mental health condition.
• The cortico-striatal-thalamic (CST) loop is traditionally implicated in OCD pathophysiology.
• Understanding broader neural network involvement is crucial for advancing treatment.

Purpose of the Study:

• To investigate functional connectivity density (FCD) and resting-state functional connectivity (rsFC) abnormalities in OCD.
• To examine connectivity within and outside the CST loop.
• To correlate neuroimaging findings with clinical symptom severity and illness duration.

Main Methods:

• Multimodal MRI was performed on 92 OCD patients and 75 healthy controls.
• Voxel-based FCD analysis identified local and distant nodal changes.
• Seed-based rsFC analysis and clinical assessments (Y-BOCS, BAI, BDI) were conducted.

Main Results:

• OCD patients showed altered short-range FCD in sensorimotor and temporal regions, and increased FCD in the left caudate nucleus.
• Long-range FCD was increased in orbitofrontal and frontal gyri.
• Enhanced rsFC was observed between frontal, cingulate, and visual processing areas; caudate FCD correlated negatively with Y-BOCS scores.

Conclusions:

• OCD exhibits widespread connectivity abnormalities beyond the CST loop.
• These alterations involve sensorimotor, executive control, and emotion-regulation networks.
• Findings provide novel insights into OCD's neural underpinnings and suggest a broader network dysfunction.