Even when you're deprived of sleep, you may feel that you're able to function just fine -- but your brain cells could be telling a different story.
A new study shows that even when we feel wide awake, "parts of our brains may be opting to go offline in a sort of rolling blackout similar to what the electric company does when demands for power spike," reports MSNBC's Body Odd blog.
Scientists conducted the experiment on rats, placing electrodes in the rats' brains and keeping the rodents awake much longer than they were used to by dropping toys into the rats' cages. The rats, though tired, would keep playing with the toys for hours.
As the rats played, researchers saw that their nerve cells would be sparking one minute and then go completely silent in a kind of nap phase.
They all seemed to look perfectly normal, but when given tasks, rats showed subtle differences in performance. For example, the rats had been taught to obtain sugar pellets by reaching a paw through a hole in their cages, which takes a lot of concentration and dexterity, says Body Odd.
But the sleep-deprived rats had much more difficulty getting the pellets into their cages, and scientists saw that the mistakes happened when nerve cells went offline in the region that controls movement.
One of the scientists behind the study pointed out that this was precisely the danger in getting too little sleep. "Think about driving -- or air traffic controllers," says Body Odd. "You might be going along just fine and then need to make a split-second decision when the wrong brain circuits go offline to catnap. The result could be catastrophic: a downed plane or a driver switching into a lane that already has a car in it."
So, whether you feel tired or not, being sleep-deprived is not only bad for your health -- it could be unpredictably dangerous.