Connectomics-based structural network alterations in obsessive-compulsive disorder.

Area of Science:

• Neuroscience
• Psychiatry
• Connectomics

Background:

• Obsessive-compulsive disorder (OCD) pathophysiology involves affect, but the cortico-striato-thalamo-cortical (CSTC) model's role of emotion processing regions is debated.
• Connectomics offers a whole-brain approach to analyze structural connectivity beyond the traditional CSTC circuitry.

Purpose of the Study:

• To investigate whole-brain structural connectivity differences in OCD patients compared to healthy controls.
• To explore the involvement of emotion-processing regions in OCD pathophysiology using a connectomics approach.

Main Methods:

• Structural T1-weighted MRI and diffusion tensor imaging (DTI) were used to create 83x83 whole-brain structural networks for 41 OCD patients and 42 controls.
• Network-based statistic (NBS) was applied to assess group differences in structural connectivity.
• Graph theoretical measures were calculated to analyze local and global network characteristics.

Main Results:

• NBS analysis identified a distinct network with decreased structural connectivity in OCD patients, including orbitofrontal, striatal, insula, and temporo-limbic areas.
• Graph theory revealed local alterations in the amygdala and temporal pole, while overall network topology remained preserved.
• This is the first study to combine NBS and graph theory in OCD research.

Conclusions:

• The findings support the involvement of temporo-limbic regions, crucial for emotion processing, in the neurobiological alterations observed in OCD.
• Structural connectivity deficits extend beyond the CSTC model, emphasizing the importance of emotion-related brain networks in OCD.