Sleeping well is very important because it allows the brain to tidy up and get rid of the waste, so to be efficient on waking.
Maintenance performed during sleep allows the proper functioning of the system and prevents any degeneration such as Alzheimer’s and many other neurological diseases.
Here are some examples that you can learn more about by following the respective links at the bottom of the page.
It is not surprising that a good night’s sleep improves our ability to remember what we learned during the day.
Researchers at the RIKEN Brain Science Institute in Japan have discovered a brain circuit that governs how certain memories are consolidated in the brain during sleep.
Brain may flush out toxins during sleep: NIH-funded study suggests sleep clears brain of damaging molecules associated with neurodegeneration.
In Alzheimer’s, for example, there are accumulations of big protein chunks in the brain, Jonathan Kipnis, a professor in U.Va.’s Department of Neuroscience and director of U.Va.’s Center for Brain Immunology and Glia said.
“We think they may be accumulating in the brain because they’re not being efficiently removed by these vessels.” He noted that the vessels look different with age, so the role they play in aging is another avenue to explore.
The cleaning system of the brain cells, the so-called mitophagy, is very weakened in animals and humans with Alzheimer’s.
When the cleaning system does not work properly, there will be an accumulation of defective mitochondria in the brain cells. And this may be really dangerous.
When an international research team improved the cleaning system in the animals, the Alzheimer’s symptoms almost disappeared, says Vilhelm Bohr, author of the study and affiliate professor at the Center for Healthy Aging and National Institutes of Health.
Now comes word of yet another way that sleep is good for us: it triggers rhythmic waves of blood and cerebrospinal fluid (CSF) that appear to function much like a washing machine’s rinse cycle, which may help to clear the brain of toxic waste on a regular basis.
The video above uses functional magnetic resonance imaging (fMRI) to take you inside a person’s brain to see this newly discovered rinse cycle in action.
First, you see a wave of blood flow (red, yellow) that’s closely tied to an underlying slow-wave of electrical activity (not visible).
As the blood recedes, CSF (blue) increases and then drops back again.
Then, the cycle—lasting about 20 seconds—starts over again.
The findings, published recently in the journal Science, are the first to suggest that the brain’s well-known ebb and flow of blood and electrical activity during sleep may also trigger cleansing waves of blood and CSF.
While the experiments were conducted in healthy adults, further study of this phenomenon may help explain why poor sleep or loss of sleep has previously been associated with the spread of toxic proteins and worsening memory loss in people with Alzheimer’s disease.
In the new study, Laura Lewis, Boston University, MA, and her colleagues at the Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston. recorded the electrical activity and took fMRI images of the brains of 13 young, healthy adults as they slept.
The NIH-funded team also built a computer model to learn more about the fluid dynamics of what goes on in the brain during sleep.
And, as it turns out, their sophisticated model predicted exactly what they observed in the brains of living humans: slow waves of electrical activity followed by alternating waves of blood and CSF.
Lewis says her team is now working to come up with even better ways to capture CSF flow in the brain during sleep. Currently, people who volunteer for such experiments have to be able to fall asleep while wearing an electroencephalogram (EEG) cap inside of a noisy MRI machine—no easy feat.
The researchers are also recruiting older adults to begin exploring how age-related changes in brain activity during sleep may affect the associated fluid dynamics.
Taking out the protein garbage becomes more difficult as neurons age (2019-08-06)
The cleaning system of the brain cells tied to Alzheimer’s (2019-02-26)
Speeding up waste disposal in the brain may slow down neurodegenerative diseases (2016-01-08)
Researchers Find Textbook-Altering Link Between Brain, Immune System (2015-06-10)
Lymphatic vasculature: A cholesterol removal system (2013-04-12)
Brain may flush out toxins during sleep (2013-11-05)
Mimicking deep sleep brain activity improves memory (2016-06-03)
For more information
Coupled electrophysiological, hemodynamic, and cerebrospinal fluid oscillations in human sleep
Fultz NE, Bonmassar G, Setsompop K, Stickgold RA, Rosen BR, Polimeni JR, Lewis LD.
This post is also available in: Italian