Professor, does your brain take a nap while you are awake?

By MAIA SZALAVITZ Friday, May 6, 2011:

Have you ever been so exhausted that you feel basically half-asleep? Turns out, that may be what's literally going on in your brain, according to a new study published in Nature.

In a study of rats, researchers found that when the animals were deprived of sleep, parts of their brains (specifically, neurons in two areas of the cerebral cortex) switched into a sleeplike state, even while the rest of the brain stayed awake — and the rats themselves appeared completely alert.

The new findings may help researchers better understand how sleep-deprivation affects human performance and may even shed light on why sleep is necessary to begin with.

Researchers led by Giulio Tononi of the University of Wisconsin-Madison measured the electrical activity in the brains of 11 rats, which they kept awake past their bedtimes by continuously introducing new objects into their cages. They found that the activity in some brain areas in the rats showed brief descents into "slow wave" sleep patterns. That's the type of sleep we experience for 80% of the night, the kind that mostly doesn't involve dreaming.

In other words, although the rats were awake, some of their brain cells were not. And the longer the rats were forced to stay awake, the more "sleepy" regions their brains registered. Read more>>