Circadian Rhythms Help Guide Waste from Brain
Wednesday, September 2, 2020
New research details how the complex set of molecular and fluid dynamics that comprise the glymphatic system – the brain’s unique process of waste removal – are synchronized with the master internal clock that regulates the sleep-wake cycle. These findings suggest that people who rely on sleeping during daytime hours are at greater risk for developing neurological disorders.
“These findings show that glymphatic system function is not solely based on sleep or wakefulness, but by the daily rhythms dictated by our biological clock,” said neuroscientist Maiken Nedergaard, M.D., D.M.Sc., co-director of the Center for Translational Neuromedicine at the University of Rochester Medical Center (URMC) and senior author of the study, which appears in the journal Nature Communications.
The findings add to a growing understanding of the operation and function of glymphatic system, the brain’s self-contained waste removal process which was first discovered in 2012 by researchers in the Nedergaard’s lab. The system consists of a network of plumbing that follows the path of blood vessels and pumps cerebrospinal fluid (CSF) through brain tissue, washing away waste. Research a few years later showed that the glymphatic system primarily functions while we sleep.
Since those initial discoveries, Nedergaard’s lab and others have shown the role that blood pressure, heart rate, circadian timing, and depth of sleep play in the glymphatic system’s function and the chemical signaling that occurs in the brain to turn the system on and off. They have also shown how disrupted sleep or trauma can cause the system to break down and allow toxic proteins to accumulate in the brain, potentially giving rise to a number of neurodegenerative diseases, such as Alzheimer’s.