Feasibility of Observing Glymphatic System Activity During Sleep Using Diffusion Tensor Imaging Analysis Along the...

Area of Science:

• Neuroscience
• Medical Imaging

Background:

• The glymphatic system clears brain metabolic waste; dysfunction is linked to neurological disorders.
• The Diffusion Tensor Imaging Analysis Along the Perivascular Space (DTI-ALPS) index measures glymphatic function non-invasively.
• Previous studies have not validated DTI-ALPS for sleep-related glymphatic changes.

Purpose of the Study:

• To assess the feasibility of using the DTI-ALPS index as a quantitative marker for dynamic glymphatic activity during sleep.
• To investigate sleep-induced changes in glymphatic function using DTI-ALPS.

Main Methods:

• Diffusion tensor imaging (DTI) data collected from 9 healthy males during wakefulness and sleep (post-sleep deprivation and zolpidem administration).
• Simultaneous MR-compatible electroencephalography used to monitor sleep states.
• DTI-ALPS index calculated from 9 regions of interest; analysis focused on participants with continuous sleep.

Main Results:

• Three out of nine regions of interest (ROIs) showed a significant increase in the DTI-ALPS index during sleep compared to wakefulness (p < 0.05).
• These increases occurred within 14-25 minutes after sleep induction.
• Significant changes were observed with FDR-corrected p-values below 0.024.

Conclusions:

• Time-series DTI analysis demonstrated a significant increase in the DTI-ALPS index within 30 minutes of sleep induction.
• The findings support the DTI-ALPS index's potential as a biomarker for glymphatic activity.
• This study provides quantitative evidence for dynamic glymphatic function changes during sleep.