Reduced orbitofrontal and parietal gray matter in chronic insomnia: a voxel-based morphometric study

Area of Science:

• Neuroimaging
• Neuroscience
• Brain Anatomy

Background:

• Chronic insomnia is prevalent but its brain mechanisms remain poorly understood.
• Previous research has not extensively investigated the structural brain changes associated with chronic insomnia.

Purpose of the Study:

• To investigate structural brain differences in chronic primary insomnia patients.
• To explore the correlation between regional brain volumes and insomnia severity.

Main Methods:

• A case-control study utilizing optimized voxel-based morphometry.
• Comparison of regional brain volumes between 24 chronic insomnia patients and 13 matched controls.
• Exclusion of psychiatric comorbidity in selected participants.

Main Results:

• Insomnia patients showed significantly smaller gray matter (GM) volume in the left orbitofrontal cortex.
• Reduced GM volume in the orbitofrontal cortex strongly correlated with subjective insomnia severity (r = -.71).
• Additional reductions in GM volume were observed in the anterior and posterior precuneus; no white matter differences were found.

Conclusions:

• This study provides the first voxel-based morphometry evidence of structural brain correlates in insomnia.
• The findings link specific brain structural changes to insomnia severity.
• Future research should explore the functional roles of affected areas (orbitofrontal cortex, precuneus) in decision-making and stimulus processing for a better understanding of insomnia.