A recent study indicates that sleep does not only help put the body to rest in aid of restoring major body functions. It can also help cleanse the mind. That is because researchers have discovered that the space between brain cells increase during sleep. This allows the brain to flush out the toxins it has accumulated during its waking hours.
The recent discovery may give sleep another role in protecting a person’s health. According to Maiken Nedergaard, M.D., D.M.Sc., co-director of the Center for Translational Neuromedicine at the University of Rochester Medical Center in New York, “Sleep changes the cellular structure of the brain. It appears to be a completely different state.”
For hundreds of years, scientists and philosophers have pondered on why people need to sleep. Scientists only discovered also recently that sleep is essential for helping improve the brain’s storage capabilities, especially in storing memories. The new study also indicates that sleep may also be a time when the brain is trying to cleanse itself from toxins that affects its daily function.
The results of the study showed that during sleep, a unique system that is called the glymphatic system is activated and becomes open. It works as the brain’s plumbing system, letting fluid rapidly flow through the brain. Dr. Nedergaard, the study’s lead author, and her team also discovered that the glymphatic system helps control the flow of cerebrospinal fluid or CSF, the clear liquid that surrounds the brain and the spinal cord.
The researchers studied the system by injecting dye into the CSF of the brain in mice and watched it flow through the brain and monitoring electrical activity in the brain. The researchers found out that the dye flowed rapidly when the mice were sleeping or anesthetized. On the other hand, the dye barely flowed when the mice were wide awake.
Dr. Nedergaard stated, “We were surprised by how little flow there was into the brain when the mice were awake. It suggested that the space between brain cells changed greatly between conscious and unconscious states.”
In order to test this, the researchers used electrodes inserted directly into the brain to measure the space between brain cells. The researchers discovered that the space between the brains increased greatly between conscious and unconscious states by as much as 60 percent.
In addition, previous studies have suggested that toxic molecules associated with neurodegenerative disorders may accumulate in the space between brains cells. The researchers tested whether the glymphatic system has an effect over this. The researchers injected mice with labeled beta-amyloid, a type of protein associated with Alzheimer’s disease. The researchers then measured how long the protein lasted in the brain when the mice were asleep or awake.
The researchers found out that the beta-amyloid disappeared faster in mice when they were asleep. This suggests that sleep normally cleans toxic molecules in the brain. The results of the said study may have important implication in the current understanding of sleep. In addition, scientists may have also discovered a potential target in form of the glymphatic system when it comes to finding possible treatments for a range of neurological disorders. Results of the study were published in the journal Science.
Source: IH/National Institute of Neurological Disorders and Stroke. “Brain may flush out toxins during sleep; Sleep clears brain of molecules associated with neurodegeneration: Study.” ScienceDaily, 17 Oct. 2013. Web. 18 Nov. 2013.