Altered default mode network and glymphatic function in insomnia with depression: A multimodal MRI study.

Area of Science:

• Neuroscience
• Medical Imaging
• Sleep Medicine

Background:

• Chronic insomnia disorder (CID) and major depressive disorder (MDD) frequently co-occur.
• The interplay between CID, MDD, and brain network function, particularly the default mode network (DMN) and glymphatic system, requires further elucidation.

Purpose of the Study:

• To investigate functional alterations in the DMN and glymphatic system in individuals with CID and comorbid MDD.
• To assess whether MDD exacerbates glymphatic dysfunction in CID patients.
• To identify neuroimaging markers for diagnosing CID with comorbid MDD.

Main Methods:

• Resting-state functional MRI (rs-fMRI) to assess DMN connectivity.
• Diffusion tensor imaging along the perivascular space (DTI-ALPS) to evaluate glymphatic function.
• Binary logistic regression for diagnostic modeling using imaging features.

Main Results:

• CID patients with comorbid MDD showed weakened DMN functional connectivity and enhanced connectivity of the posterior cingulate cortex (PCC) with external networks.
• Reduced glymphatic function, indicated by a lower ALPS index, was observed in CID patients with comorbid MDD compared to those without depression.
• Depression severity (HAMD scores) correlated significantly with specific DMN connectivity metrics.

Conclusions:

• DMN destabilization may be a neurological link between depression and insomnia.
• Comorbid MDD appears to worsen glymphatic dysfunction in CID patients.
• Neuroimaging findings offer high diagnostic efficacy for CID with comorbid MDD, underscoring the need for early depression management in insomnia.