Chronic lack of sleep contributes to a host of health problems including cardiovascular disease and diabetes. Numerous studies have also shown a strong correlation between not getting enough rest and reduced efficiency. Sleep plays a critical role but researchers have never fully understood why.
A new study has discovered a new system that is akin to scrubbing away neural waste in the brain. The process results in feeling far more refreshed and sharp. The revelations help to better understand the fundamentals of sleep and its impact in other areas.
Using mice and two-photon microscopy, researchers were able to show the increase of space between brain cells during sleep. The research shows that brain cells contract during rest. This process allows for spinal fluid to flow more freely through the brain which then flushes out toxins into the circulatory system.
“We have a cleaning system that almost stops when we are awake and starts when we sleep. It’s almost like opening and closing a faucet – it’s that dramatic,” says Dr. Maiken Nedergaard, co-director of the Center for Translational Neuromedicine at the University of Rochester Medical Center and lead author of the study.
The lymphatic system is a functional waste clearance pathway for the central nervous system (CNS) which is almost 10 times more active during sleep. The findings are profound and only demonstrate the crucial function that sleep has.
Researchers were able to demonstrate for the first time that spacing between brain cells changed dramatically.
To measure activity within the brain during sleep, researchers injected dye directly into the cerebrospinal fluid (CSF) of mice and examined how it flowed through their brains. The dye flowed rapidly during states of unconsciousness compared to when the mice were active.
The results have major implications for discovering new ways to treat neurological disorders.
The protein amyloid-beta is a waste product of the brain that accumulates and forms plaques, a severe condition which is commonly associated with patients diagnosed with Alzheimer’s. Researchers have previously demonstrated that these levels experienced a drop in mice brains during sleep.
Possible drugs are currently in testing to decrease the amount of amyloid-beta production and to further increase the amount of space between the brain cells. Experiments to measure production and clearance between states of sleep and consciousness are ongoing.
Understanding the lymphatic system functions and how it clears waste is a critical step forward.