The next time you don’t get enough sleep, imagine the power going out in your neighborhood. Because that’s what happens to your brain when you’re sleep deprived. That’s the gist of a new study we read about from the University of Wisconsin. It’s one of the first to look at what actually happens inside your brain when you don’t get enough sleep.

To find out, researchers used special electrodes to monitor individual neurons inside the brains of rats – whose brains happen to function the same way ours do. Then, researchers kept the rats awake past their usual “bedtimes,” and gave them a series of tasks to do – like pulling sugar pellets through a hole. Keep in mind, this was a task the rats did all the time, effortlessly, when they had a normal amount of sleep. So what happened?

As you might expect, the sleep-deprived rats took longer to move the pellets, and often struggled to pull them through the hole! What surprised researchers was what happened inside the rats’ brains, because while the rats seemed to behave normally, scans revealed that some brain cells were sparking “on” and “off” at unexpected times. Researchers compared it to the way power companies sometimes conserve electricity in big cities. They might shut down one block at a time in so-called “rolling blackouts.” When researchers compared these brain “blackouts” to what was going on inside the cage, they noticed the rats made more mistakes when certain brain cells switched “off.” That’s important to remember when you try to drive a car after staying up all night. As this study shows, you might feel perfectly fine behind the wheel, but your brain may be switched “off.”