2 Mar 2011

Work while you sleep

My attention was recently attracted by a short article in a French daily newspaper (Le Monde, edition 27 & 28 February 2011), that spoke of the fact that one's brain continues to work whilst one sleeps. In other words the brain never rests, or at least not completely. Of course we know this from the world of dreams, but this article spoke of the sifting of information from everyday life, allowing the brain to abandon unwanted information, whilst retaining the more important stuff. Now how does the brain know what is "important" and what is not? Maybe its a matter of which brain we are talking about (good excuse to show this beautiful image of 8 brains).

I looked around for more information on this subject, and saw various articles, including some talking about "screen-saver" mode for the brain. I am not too convinced by this particular analogy, but then I do not know any more about computers than I do about the brain (and that ain't a lot folks!). Neuroscientists have found that a resting brain (see at top of page for a picture of a resting brain), awake or not, continues to perform meaningful functions (not quite sure what a "meaningful" function is, but still). In the process of research using 16 participants, Lila Davachi, of New York University, scanned the brains of her subjects using magnetic resonance imaging. Then she showed them images containing pairs of objects and asked them to imagine interactions between them. After a few minutes another scan was made.The test was repeated, with new faces and objects being shown each time. Finally, the participants were given a quiz designed to measure their recollection of the pictures. Comparing the results of the scans before and after the experiment, researchers found a higher level of correlation of brain activity after looking at the images than before. And the more brain activity going on during "rest" after looking at the images, the better a participant performed on the quiz. It would seem that other researchers have found similar results.

The piece of reserach related in the article that I read in Le Monde involved sleep phases for the subjects. The idea, I suppose, was to test that old saying "take a good night's sleep and all will be clear in the morning." Researchers took 26 volonterres, aged between 23 and 27, and showed them a series of words to read, each word being followed either by "to remember" or "to forget". Half the test group slept the night following this, whereas the other half was deprived of sleep. Three days later their memories of the full exercise were tested. The subjects who had slept performed much better that those who had not. The scan performed during the test also revealed that the hippocampus area of the brain (see above) was more active when a word was marked "to remember" than when one was marked "to forget". And this information, it seems, is consolidated by the brain when one is asleep, whereas the person who stays awake tends not to consolidate it.

So one's brains is functioning when one sleeps. In some respects it may even be functioning better when you are asleep than when you are awake. This probably doesn't mean that you should go to sleep at work, but it does mean that you need to sleep in order to be able to work well and retain stuff that you have recently taken in. Does this explain the use of short naps, or siestas? I do not know. It does give me an excuse to show this image (entitled Android at rest) which I also find very beautiful.

This particular piece of research does not tell us either whether men's brains are different from women's, but one can perhaps make assumptions on that issue from personal experience...