Sleep flushes dementia-linked waste from brain: Study

If you have ever slept over a problem and woken up to a Eureka! moment you would have probably wondered at the amazing power of sleep to recharge your brain cells.

But there apparently there is more to it than that and scientists say sleep allows your brain to undergo a mop-up process that removes waste products linked to Alzheimer's and dementia.

Science online has published the results yesterday has the details.

According to a research team at the University of Rochester Medical Center (URMC) which used high-tech imaging to look deep into the brains of mice, the brain functioned differently while asleep than awake, sweeping away accumulated proteins at a much faster rate.

Led by Maiken Nedergaard, MD, who co-directs the URMC's Center for Translational Neuromedicine, the researchers uncovered a waste-draining system they called the ''glymphatic system'' which was 10 times more active during sleep than while awake.

This nocturnal cleaning system removed proteins called amyloid-beta, which accumulate into the plaques contributing to Alzheimer's disease and dementia.

The term ''glymphatic system'' was first used by the team last year, when they used new imaging technology known as two-photon microscopy to discover a scrubbing process taking place around brain cells, known as glial cells.

In it were so, according to Clete Kushida, medical director of the Stanford Sleep Medicine Center sleep would perhaps be even more important in slowing the progression of further damage.

Kushida was not a member of the research team.

It is known that people who do not get enough sleep have trouble learning and making decisions, and are slower to react.

However, despite years of research, scientists could not agree on the basic purpose of sleep with reasons ranging from processing memory, saving energy to regulating the body.

The new research lends fresh support to a long held view that the brain goes on a cleaning spree, when we are asleep.

In the new study, scientists injected the brains of mice with beta-amyloid, a substance that built up in Alzheimer's disease, and tracked its movement. They found that the substance was flushed out faster in sleeping mice than in mice that were awake.

The team further found that brain cells tended to shrink during sleep, which widened the space between the cells, allowing waste to pass through that space more easily.

According to Nedergaard, though the work involved mouse brains, the plumbing system also existed in dogs and baboons, and it was logical to think that the human brain also cleared away toxic substances.