How your brain sleeps.

[GrandMasterTerwynn]

According to this study:

Study Reveals How Your Brain Sleeps
By Robert Roy Britt
LiveScience Managing Editor
posted: 29 September 2005
02:01 pm ET


Your brain never stops working. But it does cease talking to itself when you lose consciousness, a new study shows.

Scientists have long wondered what the brain does and doesn't do during deep sleep. It remains active, they know. So what's the difference between consciousness and the lack of it?

When we're awake, different parts of the brain use chemicals and nerve cells to communicate constantly across the entire network, similar to the perpetual flow of data between all the different computers, routers and servers that make up the Internet.

In the deepest part of sleep, however, the various nodes of your cranial Internet all lose their connections.

"The brain breaks down into little islands that can't talk to one another," said study leader Giulio Tononi of the University of Wisconsin-Madison.

Tononi's team used a non-invasive procedure to activate select parts of the brain. Subjects had electrodes attached to their heads to monitor how each stimulation triggered reactions elsewhere.

In the early morning, when subjects were dreaming, signals careened around the noggin similarly to when they were awake. But at night, during deeper sleep, the picture was much different.

"During deep sleep early in the night," Tononi said, "the response is short-lived and doesn't propagate at all."

Consciousness has long mystified scientists. The new finding suggests that it depends on the brain's ability to integrate information, Tononi says.

The compartmentalization might also help the brain's synapses, which make all the connections that give us thought, to take a break, according to Tononi's colleague, Marcello Massimini.

"This process would allow cortical circuits to eliminate noisy synapses and renormalize in order to be ready for the next day," Massimini told LiveScience. The reduced activity might also help explain why performance in various tasks improves after sleep, he said.

The machine used to conduct the experiments is new. It generates a magnetic field to provide stimulation, and Tononi's team expects this to be the first of many similar studies that will help researchers better understand the mind and specific disorders of the brain.

The study is detailed in the Sept. 30 issue of the journal Science.

This is definitely interesting. From both the standpoint of what, exactly, is going on while one sleeps, and further proof that human consciousness is nothing more than a sum of the brain's activity (but only when it's all synched together.)

[Edi]

So basically one implication of this is that when people go into deep sleep, for a time they cease being who they are in a sense? I know that's a little exaggerated, but that's the basic idea for provoking some interesting discussion and what-if scenarios.

Edi

[squidman001]

how would the brain know when to come back together if thier disconnected?

p.s. my last name is massimini, like the guy in the article... its a small world after all!

[Magnetic]

I wonder how dreaming plays into that time?

What is interesting about dreams is that most dreams I have are not of personal experiences or things I've seen on TV/movies. Where my brain gets those images from, I have no idea.

[drachefly]

The article said that during dreaming sleep the brain is internally connected -- it's the non-dreaming, deep sleep that disconnects.

[Magnetic]

Oh. .. . missed that. Thanks!