Brain’s waste removal system unveiled: Neurons act as miniature pumps during sleep

Researchers at Washington University School of Medicine in St. Louis have discovered that brain cell activity during sleep is responsible for propelling fluid into, through, and out of the brain, cleaning it of debris. This process is facilitated by individual nerve cells coordinating to produce rhythmic waves that propel fluid through dense brain tissue, effectively washing the tissue in the process.

The findings, published in Nature, suggest that synchronized neural activity powers fluid flow and removal of debris from the brain. According to Li-Feng Jiang-Xie, PhD, a postdoctoral research associate in the Department of Pathology & Immunology, these neurons act as miniature pumps, and building on this process could potentially delay or prevent neurological diseases, including Alzheimer’s and Parkinson’s disease, in which excess waste accumulates in the brain and leads to neurodegeneration.

The brain’s cleaning process during sleep has long eluded scientists due to the challenge of observing it in the living brain. However, using new imaging technologies, researchers were able to observe in mice a plumbing system that piggybacks on the brain’s blood vessels and pumps cerebrospinal fluid (CSF) through the brain’s tissue, effectively flushing waste back into the circulatory system. This timely removal of waste from the brain is essential, as the accumulation of toxic proteins such as amyloid-beta can lead to neurodegenerative diseases .

The study’s senior author, Jonathan Kipnis, PhD, highlighted the critical importance of the brain disposing of metabolic waste to prevent neurodegenerative diseases. The findings suggest the possibility of developing strategies and potential therapies to speed up the removal of damaging waste and prevent dire consequences.