Monday, February 14, 2011

why do we sleep?


Video - Jay Electronica Dimethyltryptamine

Physorg | While we can more or less abstain from some basic biological urges—for food, drink, and sex—we can’t do the same for sleep. At some point, no matter how much espresso we drink, we just crash. And every animal that’s been studied, from the fruit fly to the frog, also exhibits some sort of sleep-like behavior. (Paul Sternberg, Morgan Professor of Biology, was one of the first to show that even a millimeter-long worm called a nematode falls into some sort of somnolent state.) But why do we—and the rest of the animal kingdom—sleep in the first place?

“We spend so much of our time sleeping that it must be doing something important,” says David Prober, assistant professor of biology and an expert on how genes and neurons regulate sleep. Yes, we snooze in order to rest and recuperate, but what that means at the molecular, genetic, or even cellular level remains a mystery. “Saying that we sleep because we’re tired is like saying we eat because we’re hungry,” Prober says. “That doesn’t explain why it’s better to eat some foods rather than others and what those different kinds of foods do for us.”

No one knows exactly why we slumber, Prober says, but there are four main hypotheses. The first is that sleeping allows the body to repair cells damaged by metabolic byproducts called free radicals. The production of these highly reactive substances increases during the day, when metabolism is faster. Indeed, scientists have found that the expression of genes involved in fixing cells gets kicked up a notch during sleep. This hypothesis is consistent with the fact that smaller animals, which tend to have higher metabolic rates (and therefore produce more free radicals), tend to sleep more. For example, some mice sleep for 20 hours a day, while giraffes and elephants only need two- to three-hour power naps.

Another idea is that sleep helps replenish fuel, which is burned while awake. One possible fuel is ATP, the all-purpose energy-carrying molecule, which creates an end product called adenosine when burned. So when ATP is low, adenosine is high, which tells the body that it’s time to sleep. While a postdoc at Harvard, Prober helped lead some experiments in which zebrafish were given drugs that prevented adenosine from latching onto receptor molecules, causing the fish to sleep less. But when given drugs with the opposite effect, they slept more. He has since expanded on these studies at Caltech.

Sleep might also be a time for your brain to do a little housekeeping. As you learn and absorb information throughout the day, you’re constantly generating new synapses, the junctions between neurons through which brain signals travel. But your skull has limited space, so bedtime might be when superfluous synapses are cleaned out.

And finally, during your daily slumber, your brain might be replaying the events of the day, reinforcing memory and learning. Thanos Siapas, associate professor of computation and neural systems, is one of several scientists who have done experiments that suggest this explanation for sleep. He and his colleagues looked at the brain activity of rats while the rodents ran through a maze and then again while they slept. The patterns were similar, suggesting the rats were reliving their day while asleep.

4 comments:

SoloInto said...

First off big fist bump for the Jay Electronica look.

While I agree to an extent with your statement, don't you agree that we don't necessarily need to understand completely the nature of a given topic to make observations upon which lead to practical and beneficial conclusions i.e. quantum mechanics and computing? Is it not that an incomplete understanding is the building block for that which is?

Is your beef about the inherent prioritization of research on this one CNu? Does a better understanding of sleep have a better payout than a search for a more complete understanding of the universe, even if along the way there are some stupid theories posited?

CNu said...

Naw mang, forget about "science" and "research".

It's simultaneously simpler and much deeper at the same time - and has nothing whatsoever to do with the lab coat set.

I can't think of a clearer and more decisive indictment of cultural dysfunction or madness than that this one has no grasp of the purpose of its members most basic and pervasive functions.

I sincerely consider it the exact equivalent of cattle not understanding the function of a prod or of a feedlot.

nanakwame said...

Hello Serendipity

CNu said...

Trying to see if I can instigate a momentary critical mass;

http://cobb.typepad.com/cobb/2011/02/god-good.html

http://denmarkvesey.blogspot.com/2011/02/s-t-y-l-e.html

Before Y'alls Time - But We Don't Have Any Voices Like Carl Rowen Any More...,

LATimes  |   If you’ve ever heard that soothing voice or read those scholarly sentences, you’d know it’s him. Syndicated columnist Carl Row...