Why do We Sleep? -Scientists Search for the Answer

For many of us, sleep is a precious gift, akin to coffee, that was gifted to us early on in our evolution. But scientists have long been completely baffled as to just why we sleep, and just what constitutes sleep anyway. A new study attempts to address just why we sleep.

"We don't understand the purpose of sleep, but it must be important because all animals do it," Chiara Cirelli and Giulio Tononi, the study authors say, who describes the search for sleep as like the search for the mythological phoenix.

Some scientists believe that sleep is not important by itself in mammals and birds, and is just a way to impose a quiet and immobile state. Cirelli and Tononi reject this opinion, pointing to the fact that, so far, there has been no evidence of any animal not sleeping.

Even the dolphin, which is often used as an example of an animal that does not sleep because it keeps moving, has developed its own method of sleeping. The dolphin shuts down one half of its brain, swimming with one eye closed, and exhibiting the slow waves characteristic of deep sleep.

"The very fact that dolphins have developed the remarkable specialization . . ., rather than merely getting rid of sleep altogether, should count as evidence that sleep must serve some essential function and cannot be eliminated," Cirelli says.

Cirelli also points to sleep deprivation, and the after-effect of having gone a long time without sleep, as examples of the necessity of it. Sleep deprivation has been shown to kill animals like rats, flies and cockroaches, as well as humans who suffer from genetic insomnia. And when a human rebounds from lack of sleep, they sleep for a long time to recuperate.

Their hypothesis suggests that sleep acts as a way for the brain to regroup after a hard day. Sleep theoretically gives the synapses – which have been escalating in strength during the day – a chance to slow down again, and return to a base level. Given that the brain uses 80% of its energy in order to keep the synaptic activity happening, there is an obvious need for the brain to rest.

They also suggest that sleep allows for the consolidation of new memories, and the trashing of older, random and unimportant memories from the day passed. This theoretically allows for more learning the following day. "While there may still be no consensus on why animals need to sleep, it would seem that searching for a core function of sleep, particularly at the cellular level, is still a worthwhile exercise," Cirelli concludes.

Posted by Josh Hill.

Related Galaxy posts:

 

 

Science of Sleep: 5 Reasons Why You Might Want More of It
"Sleepless" Mutation Found Responsible for Sleeplessness
Hey Night Owls: It's in Your Genes
Study Finds that Mobile Phones Affect Our Brains & Disrupts Sleep
The Science of Siesta: Research Finds That Napping Improves Brain Functioning
DARPA Develops Brain Chemical to Replace Sleep
The Ultimate Mystery: What Do Our Brains Do While Sleeping?
Science of Sleep: 5 Reasons Why You Might Want More of It

Source: http://www.physorg.com/news138941239.html

Comments

[ar-lock]

Yawn.....

[Morf]

Yes, I can't really define naps, but after a good one I feel more alive and perhaps even more human. Though perhaps a cat feels more fully its cat-ness after a good nap as well...

So perhaps sleep is undefinably essential - like art.

[True]

Sure. I understand this completely. It's always been my opinion that sleep acts as a way for the brain to kind of defrag itself. When a days worth of activity goes into your brain it takes up random space, in layman's terms, like just dropping tetris blocks where they fall. And deep sleep (including dreaming) is your brain re-arranging these ideas/memories/data into a more functional space. If you don't understand.. just sleep on it... you'll get it in the morning.

[Josh]

Maybe there is a way to have a journaling memory system for your brain so you don't have to defrag.

[Doug Brenner]

We have to sleep so that our brains can physically index the day's impressions. For us to be free of the need of sleep, we would need to attain the level of waking consciousness wherein each impression is consciously digested and stored. It is a state of combined consciousness of the self and of the world. Attainment of this is rare, but the closer we get to it, the less sleep we need; and it also becomes possible to retain consciousness both during the process of falling asleep, and during physical sleep itself. The physical healing which occurs during sleep is periodically necessary, but this can also happen deliberately during meditative states.

[fasunlade isreal adeson]

I have love to work on this verry articul too furtunately i run into the answer to this question why do wesleep? and am so hapy to see this but if there is any additive ifnformation how can i pass it forword to you?
Am from Nigeria west Africa.

[saci]

How about this one.. "cause we're tired!!"

Yeh!!.. I think I've solved it! Give me the $1 million grant!

[sleepy time gorilla]

i want my 10 minutes back from this article

[knoxvilledaniel]

We have to have REM sleep to process the information we pick up during the day in dreams, the brain needs " down time ". Without it, we can go insane. We need sleep to keep our bodies from over - accumulating fatigue poisons.

This must be ANOTHER slow news day for the folks at Daily Galaxy..... !!!

[ady]

I'd like to sleep only 3 hours a day and to be rested. There's so much I should do and there's so much work to be done

[Mr. Buslon]

we need to sleep so that our TAMPAYAK will not explode!!!

[Mr. Buslon]

we need 2 sleep for us to satisfy our needs; like having a wet dreams i realy enjoy it every time it happened.

[Mr. Buslon]

we need 2 sleep for us to satisfy our needs; like having a wet dreams i realy enjoy it every time it happened.

[Mr. daryl]

for me we need to sleep so that our body can relax and it can survive in the times of sex.

[43P04T34]

OK, all animals sleep. We've established that. During sleep there is no motion which is deliberate as motion is during awake. This can be observed even in one-celled animals. Deliberate motion is observed when an animal is in search of food, is ingesting food, is procreating, whether in one-celled animals or the most complex multi-celled animals.

The question to pursue, then, is an examination of the metabolic activities (whether anabolic or catabolic) during the phases of deliberate motion (awake) and the absence of deliberate motion (asleep). I believe this pursuit will reveal that sleep and awake are a behavioral description of a metabolic balance between anabolism and catabolism. In other words, sleep is, like awake is, a behavioral description of the most fundamental metabolic reality of all, the ongoing shift in every organism between the predomination of anabolic and catabolic processes.