Study Reveals That the Brain Cleans Itself During Sleep

Study Reveals That the Brain Cleans Itself During Sleep

                                       

While the Body Sleeps and the Mind Works... A Study Changes Our Concepts of Sleep

A new scientific study conducted by researchers at Mass General Brigham using advanced, next-generation imaging techniques has revealed that the brain exhibits a coordinated shift in its activity when we fall asleep.

The results of the study, published in the journal Nature Communications, show that the brain does not completely "switch off" when we fall asleep, but rather reorganizes its activity in a coordinated manner. In the deep stage of sleep known as non-rapid eye movement (NREM) sleep, areas responsible for movement and sensory perception remain active and continue to consume energy, while areas associated with thinking, memory, and imagination quiet down and use less energy.

"These findings help us understand how the brain remains responsive to the outside world even as consciousness fades during sleep," said Dr. Jingyuan Chen, a researcher at the Athenola A. Martinus Center for Biomedical Imaging at Massachusetts General Hospital.

Chen added that the study provides new insights into the mechanisms of neurological diseases and sleep disorders, thanks to the advanced techniques the team used, including EEG-PET-MRI, which combines electroencephalography, functional magnetic resonance imaging, and positron emission tomography to monitor glucose metabolism.

The researchers conducted their experiments on 23 healthy adult volunteers during short periods of daytime sleep. The results showed that brain energy consumption gradually decreases as sleep deepens, while blood flow becomes more dynamic, particularly in sensory areas that remain active. Increased cerebrospinal fluid flow was also observed, supporting the hypothesis that sleep plays a key role in clearing the brain of waste.

The team emphasized that future research will focus on studying larger and more diverse groups, with longer sleep recordings and the use of more accurate tools to measure brain metabolism and differentiate between sleep stages.