Brain Undergoes ‘Cleaning’ Process Whilst Asleep, Study Finds

Amy Taylor October 21, 2013

Want to clear your mind? Have a good night sleep. According to a new study, our brain undergoes a ‘cleaning process’ whilst we sleep, where it literally clears away the toxins responsible for Alzheimer’s disease and other neurological disorders.

The purpose of sleep has been a subject of scientific and philosophical scrutiny since the time of ancient Greeks. Practically all animals sleep on a daily basis. This makes researchers believe that sleep is a fundamental biological process living organisms need to survive.

The new study, which was published in the journal Science, reveals that the glymphatic system – the brain’s ‘waste removal’ area, is highly active during sleep. Such system is responsible for eliminating toxins known to cause Alzheimer’s disease and other brain disorders.

Researchers also found that during sleep, brain cells reduce in size, allowing the waste to be removed more effectively.

Using advanced brain scanning technologies, such as the two-photon microscopy, scientists at the University of Rochester Medical Centre found that the glymphatic system acts as the brain’s ‘plumbing’ system which piggybacks on the brain’s blood vessels and pumps cerebral spinal fluid (CSF) through the brain’s tissue, flushing accumulated wastes back into the circulatory system.

Sleep boosts the brain’s detoxifying ability

One possible reason for the heightened activity of the glymphatic system during sleep, according to the researchers, is the fact that the amount of energy consumed by the brain does not reduce dramatically during sleep. They theorised that the cleaning process may not be compatible with all other functions the brain performs when it is awake.

What’s more, brain cells tend to ‘shrink’ by 60 per cent during sleep. This contraction creates more space between the cells and allows the cerebral spinal fluid (CSF) to wash more freely through the brain tissue. On the other hand, the brain cells are closer together when the brain is awake, restricting the flow of CSF.

This study echoes the findings presented last year, which revealed that the brain has its own ‘waste removal’ system separate from the lymphatic system. According to the researchers, the lymphatic system does not extend to the brain because it maintains its own closed ‘ecosystem’ and is protected by a complex system of molecular gateways called the ‘blood-brain barrier’ which strictly controls what enters and exits the brain.

Previous studies suggest that memory consolidation occurs during sleep, which plays an important role in learning. This and the recent findings support the growing idea that sleep may aid in the prevention and treatment of various illnesses, particularly neurological disorders.

Source of this article:

Sleep Drives Metabolite Clearance from the Adult Brain