Association between symptom severity and internal capsule volume in obsessive-compulsive disorder

Area of Science:

• Neuroimaging
• Neuropsychiatry
• White Matter Imaging

Background:

• Neurobiological models suggest white matter tract involvement in obsessive-compulsive disorder (OCD) pathophysiology.
• Systematic evaluation of white matter volumes in OCD using magnetic resonance imaging (MRI) is limited.

Purpose of the Study:

• To investigate white matter volume differences in the cingulum bundle (CB) and anterior limb of the internal capsule (ALIC) in OCD patients compared to controls.
• To explore correlations between regional white matter volumes and OCD symptom severity.

Main Methods:

• Utilized 1.5T MRI to assess white matter volumes in 19 OCD patients and 15 controls.
• Employed optimized voxel-based morphometry for between-group comparisons after spatial normalization and segmentation.
• Correlated regional white matter volumes with OCD symptom severity ratings.

Main Results:

• Obsessive-compulsive disorder patients exhibited significant global white matter reductions compared to controls.
• No specific white matter volume deficits were found in the predicted CB and ALIC regions.
• Significant positive correlations between bilateral ALIC white matter volumes and OCD severity scores were identified.

Conclusions:

• Findings provide evidence for OCD-related abnormalities in the anterior limb of the internal capsule (ALIC).
• Suggests potential connectivity dysfunction within frontal-striatal-thalamic-cortical circuits in OCD.
• Further research is needed to define the role of white matter alterations in OCD pathophysiology and neurosurgical targeting.