Night sleep influences white matter microstructure in bipolar depression

Area of Science:

• Neuroimaging
• Sleep Medicine
• Psychiatry

Background:

• Circadian rhythm alterations and sleep disruption are key features of bipolar disorder (BD).
• Diffusion tensor imaging (DTI) indicates widespread white matter (WM) microstructure changes in BD patients.
• Sleep is crucial for myelination and oligodendrocyte precursor cell proliferation.

Purpose of the Study:

• To investigate the association between DTI-derived WM microstructure measures and sleep quantity in individuals with BD.
• To explore how sleep impacts the physical structure of white matter in the brain.

Main Methods:

• Sixty-nine inpatients with a bipolar I disorder depressive episode were studied.
• Whole-brain tract-based spatial statistics analyzed DTI measures (AD, RD, MD, FA) of WM microstructure.
• Sleep quantity was assessed using the Pittsburgh Sleep Quality Index (PSQI) and actigraphy in a subsample.

Main Results:

• Fractional anisotropy (FA) positively correlated with actigraphy and PSQI measures of time asleep (TA) and total sleep time (TST).
• Radial diffusivity (RD) showed an inverse association with actigraphy and PSQI measures of TA and TST.
• Affected WM tracts included the corpus callosum, cingulate gyrus, and corticospinal tract, among others.

Conclusions:

• Findings suggest a link between sleep disruption and altered WM microstructure (reduced FA, increased RD) in specific brain tracts in BD.
• These microstructural changes may impact functional connectivity within the brain in individuals with BD.