Skip to main content

First-of-its-kind study links the sleeping brain to toxin-clearing

By November 12, 2019Commentary, In the News

Contributed by Bryce Mander, PhD

A new landmark study from researchers in Boston was published in Science this month. This study linked human brain waves during deep sleep, called “slow waves,” with the pulsating flow of cerebrospinal fluid (CSF) through the brain.

Fultz et al., 2019, NPR


This study is important because it is the first to directly link sleeping brain waves with a mechanism thought to clear the brain of metabolic waste and toxins, called the “glymphatic system.” Prior studies in rodents indicate that the glymphatic system actively clears Alzheimer’s disease pathology, as well as other toxins and waste products, from the brain.

Furthermore, the study reveals that this process depends on slow waves during deep sleep in humans, which has implications for the role of sleep in Alzheimer’s disease risk and progression. Slow waves are disrupted by both aging and Alzheimer’s disease, but behavioral, electrical, and pharmacological interventions may be able to counteract this disruption.

Future studies will need to build on this study’s findings by examining how slow wave-dependent CSF pulsating flow is related to the burden and accumulation of waste and toxins in Alzheimer’s disease, and whether slow wave treatment interventions impact CSF flow and prevent this pathological accumulation.

Bryce Mander, PhD, is Assistant Professor of Psychiatry & Human Behavior at UCI. He received his PhD in Neuroscience at Northwestern University, and completed his postdoctoral fellowship in the Department of Psychology at UC Berkeley. His research looks at how sleep disturbance impacts brain function, thinking, and memory in older adults, particularly those at risk for dementia. In his studies, he combines the use of multiple brain imaging tools, such as MRI, EEG, and PET, with behavioral testing to uncover the mechanisms linking sleep disturbance to cognitive decline in later life. Dr. Mander is one of the fields leading experts in the neuroscience of sleep and has published many important findings on the link between sleep and brain health.