Feeling Groggy? Your Brain May Be Half Asleep

Ann Lukits:

Sleep deprivation can make it hard to concentrate. A possible reason is that neurons in different regions of the brain seem to go "off line," or shut off for brief periods, during forced periods of wakefulness, according to a study of rats published in Nature. U.S. and Italian researchers kept laboratory rats awake for four hours past their normal sleep time by stimulating them with new objects. EEG (electroencephalogram) readings, which test the brain's electrical activity, were typical of an awake state and the rats moved about freely with their eyes open. However, electrodes implanted in the rat brains showed that some neurons went off line briefly in seemingly wide-awake animals while other neurons remained on. Neuronal off periods increased with prolonged sleep deprivation, impairing the rats' performance in the routine task of reaching for a sugar pellet. Researchers said these off periods during wakefulness aren't well understood but they may be a means of conserving energy or part of a restorative process.

Caveat: It's not clear if the periods of neuronal off-time reflect the capacity of neurons to exist in two states, a phenomenon known as bistability, researchers said.

Posted by Jim Zellmer at June 1, 2011 1:44 AM
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