They say that a good nights rest can clear the mind. The functions of sleep are numerous, from imposing a state of rest on the body, to memory processing. There is no question that sleep is essential for us to function, but there seems to be a debate between scientists as to what its basic function entails. A new study conducted by the University of Rochester Medical Center adds evidence to one of the long-standing functions of sleep, which is described as a way for the brain to “clean up” the accumulations from our waking hours. This leads to a possible new purpose for sleep in regard to health and disease.
For the first time, researchers discovered that the space between brain cells might be enlarged during sleep, which could allow for the brain to rid itself of toxins that build up over time. The discovery of this “plumbing” system, named the glymphatic system, may allow fluid to travel through the brain. Working with mice, they were able to observe this occurrence by injecting and then watching dye flow through the brain of the sleeping mouse. At the same time, brain activity was monitored. They found that the dye flowed rapidly while the mouse was asleep, and in contrast, it hardly flowed at all while the same mouse was awake.
This discovery may be a catalyst in new research involving neurological disorders in humans, as there may be a connection between the glymphatic system and these conditions. The researchers tested this connection by injecting mice with a protein associated with Alzheimers disease, and took note of how long it lasted in their brains while they were both awake and asleep. The results mirrored the initial findings, and suggest that sleep may clear the brain of toxic molecules. Jim Koenig, Ph.D., a program director at NINDS states that, “this means the cells regulating the glymphatic system may be new targets for treating a range of disorders.”
Overall, the study is well executed from an experimental standpoint. There was a variable being manipulated, which was the state of consciousness of the mice. Altering whether mice were awake or asleep resulted in a change in the cellular structure of the brain. It’s hard to say for sure that sleep directly affects the enlargement of the space between brain cells, even though the increased movement of fluids during that time gives a strong causal link. Still, correlation does not equal causation. It could be something else entirely, such as any third variable. Additionally, I think that reverse causation could be ruled out, because it seems unlikely that the shrinkage of brain cells causes one to become unconscious. And in any case, the results could be due to chance.
The implications of such an experiment may lead to similar studies in human brains. Do you think it would be ethical for researchers to conduct this experiment on humans? Also, based of the results of the experiment, would it be a benefit to us to get more sleep if it may prevent a range of neurological problems? We already know sleep is important, so this just adds another reason for us to catch some Z’s.
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