Sleep cleanses the brain of toxins: sleep, toxins, brain: Why do we sleep?

Why are we sleeping? This is a question that bothers not only scientists. It seems that an answer has been found, because it turns out that sleep can literally clear the mind. Researchers at the University of Rochester in New York have found that during sleep, the spaces between the brain cells increase in size, which allows toxins to be removed from it.
It is believed that sleep is necessary for learning and remembering. The discovery of American scientists may prove that sleep is mainly needed to cleanse the brain of toxins - during sleep cells shrink, the spaces between them increase, which causes faster leaching of toxic substances.

The theory of brain cleansing is based on the glymphatic system discovered in the last year by the same scientists from the University of Rochester. This system is associated with glia cells and is the equivalent of the lymphatic system. The cerebrospinal fluid flows through the glymphatic system, draining unnecessary substances from the brain and providing nutrients.

In experiments, scientists studied the glymphatic system by injecting the dye into the mouse's cerebrospinal fluid and observed its flow through the brain while monitoring the electrical activity of the brain. Injected dye appeared to flow quickly through the brain while the mouse was sleeping. However, when the mouse was awake, the dye flow was very low. These results suggested that the space between brain cells varies depending on whether the mouse is sleeping or not. To check this, the researchers decided to measure these spaces. It turned out that the size of the space between brain cells increases by 60 percent during sleep, this is due to the shrinkage of cells, probably glial cells.

In subsequent experiments, it was examined whether the glymphatic system controls the accumulation of toxins in the intercellular spaces of the brain. In neurodegenerative diseases, such as Alzheimer's disease, toxic substances accumulate in the brain and in the case of this disease it is a protein - beta-amyloid. Subsequent experiments involved injecting stained beta-amyloid into mice and observing how long the injected protein remains in the brain when the mouse is asleep and when not asleep. Beta-amyloid has been shown to be cleared faster from the brain when the mouse is asleep, which shows that the brain is cleared of toxic substances during sleep.

These results also suggest that if the brain cleansing process is disturbed, there may be disturbances in its functioning, which can lead to neurodegenerative diseases such as Alzheimer's disease. The authors of the study say that cells that control the lymphatic system may be a target in research into therapies for various diseases.

Analogous human studies are planned to establish the true meaning of the results.
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