Revealed: why we need a good night's sleep
Scientists warn of the dangers of sleepless nights after discovering how brain clears out day's mental rubbish
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Independent Minds
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A video portrait of David Beckham sleeping, by the artist Sam Taylor-Wood, shown at the National Portrait Gallery
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To sleep, perchance to dream, said Hamlet. Now scientists have shown that sleep is more about getting rid of the previous day's mental rubbish than it is about dreaming.
A study into slumber has found that the nerve connections built up in the brain during a busy day are pruned back during the night in an attempt to keep the mind from overloading on junk information.
The findings lend support to the idea that a good night's sleep is essential for consolidating important memories of the previous day and getting rid of things that would otherwise clog up the system.
The researchers behind the study said the results showed how important it was for people to get a good night's sleep to be on top form the next day.
"Right now, a lot of people are worried about their jobs and the economy, and some are no doubt losing sleep over these concerns," said one of the authors, Paul Shaw, from the Washington University School of Medicine in St Louis.
"But these data suggest the best thing you can do to make sure you stay sharp and increase your chances of keeping your job is to make getting enough sleep a top priority."
The research was based on analysis of fruit flies. The scientists believe that these simple creatures are a good model of sleep in humans because, like people, flies need between six and eight hours a night and show physical and mental signs of deprivation if they fail to get enough.
Like humans, fruit flies exposed to a busy day's activities need more sleep. Those raised in crowded conditions sleep two or three hours longer than those kept in solitary confinement and flies that are kept active with "mental workouts" sleep longer than those that are not.
Previous studies had shown that sleep promotes learning and memory in animals. The latest research went further by showing that the connections (synapses) between nerve cells in the brain are built up during the day and are pruned after a good night's sleep, Professor Shaw said.
"There are a number of reasons why the brain can't indefinitely add synapses, including the finite spatial constraints of the skull. We were able to track the creation of new synapses in fruit flies during learning experiences, and to show that sleep pushed that number back down," he said.
The scientists kept the fruit flies in a specially designed "fly agitator" with a robot arm that occasionally shook the resting platforms for the flies to prevent them from sleeping. The scientists found physical changes in the brains of these sleep-deprived flies – specifically, a build-up of the proteins that connect one nerve cell to another.
When the scientists analysed the brains of the flies after they had slept, the level of these proteins had dropped, indicating that the nerve connections themselves had become weaker or even eliminated during the night.
"At the end of sleep, the strongest synapses shrink, while the weakest synapses may even disappear," said Chiara Cirelli, from the University of Wisconsin-Madison, another author of the study, published in Science.
"Much of what we learn in a day, we don't really need to remember," she said. "If you have used up all the space, you can't learn more before you clean out the junk that is filling up your brain."
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Comments
Perhaps science will soon prove that poking ourselves in the eye is bad for vision, and that breaking an ankle is not, as was previously supposed, good for our health!
Flawed logic in that sentence.
Who'd have thunk it?!
Who previously supposed breaking an ankle was good for health?
How the god squad have managed to make this about God is quite bizarre. Their self confessed teeny tiny brains with minimal intellect and comprehension logically inferring that God exists 'because we dream' is blasphemy in the highest order.
I think you win. To my knowledge and I am none of the above, we need 8 hours under the ages of 25 to 35, more for the kids say 10 and 5 hours above the 50 years. These are the prescribed hours my granny who lived to 104.
I thank you
Firozali A. Mulla
Perhaps it is more interesting to ask exactly what a memory is? Is it a "fact" or is it a smell, an image or taste?! For I often remember the most pointless things at random times which appear to have to relation to anything else. But I am not a philosopher so I will leave these questions to soeone else...
And the brain architecture of a fruit fly may be similar to that of the average Labour minister, but I don't accept that the findings extend to the rest of us.
You probably don't care what an 18 year old girl has to say (most people don't) but I was just so struck by the attacking nature of some of these comments. I'm sorry if i have offended anyone! I was just intrigued, me being a young girl who still has to experience the world! :)
"What is so bad about the monetary system is that it channel's the human ability to channel "faith" (monetary system) into inhuman, oppressive and regressive ideas" - I guess like any other organised religion then?! ;-)
everyone happy now?
you should be- you've all managed to annoy one another no end
me I found it dead entertaining
Did somebody get paid money for reiterating the wisdom of the ages as though he had invented it?
Thankfully a new pharma-regimen has been introduced which shows promise for me. The medicined I speak of is known by its trade-name Xyrem. It's true ID is GHB, also known as the date-rape drug.
Due to the unfortunate actions of a few depraved individuals who have used this chemical to drug unsuspecting women(and men) for their sexual abominations, the FDA has chosen to regulate this drug to the point it is prohibitively expensive for law-abiding and moral people such as myself. I cannot afford this medication without insurance. If not for the regulatory horror of the FDA, I could make the substance myself for less than $20/month. But I doubt these regulations have slowed down the cretans who take advantage of others.
I can only hope that in the near future an epiphany will overcome the world of regulation and decent fold like me will have unfettered access to the medication we need.
But I won't hold my breath.
So I am glad that as a young person I became defiant against all attempts to rob me of sleep. If it was necessary to step on toes I did. Thank goodness. Never had an illness more serious than a cold as a result, and never took more than 2 or 3 sick days a year.