This is your brain on sleeplessness

You could not have designed a better experiment had I been a rat in a maze. I'd been confidently getting by on five, maybe six hours of sleep a night for two weeks, juggling work with a rigorous academic seminar in Switzerland. I figured it was a small price for the experience of a lifetime. After all, no one ever said that having it all didn't mean making some sacrifices — and what easier sacrifice is there to make in your schedule than sleep?

The only problem was that now I couldn't figure out how to get to my clothes. I knew they were behind a door in the basement of my aparthotel. But was it the door with an image of a barbell, a bicycle or a washing machine on it? Why couldn't I figure it out? And why couldn't I even remember how to use my key card? 

"You had a glimpse into what dementia feels like," Sara C. Mednick, a cognitive neuroscientist and author of "The Power of the Downstate: Recharge Your Life Using Your Body's Own Restorative Systems" and "Take a Nap! Change Your Life," tells me a few days afterward. This wasn't the groggy feeling of the aftermath of a late night out. This was the shambling, full system malfunction of a body and brain that could no longer outrun its own basic need for rest. I didn't feel tired. I felt deeply, frighteningly disoriented. There's a good reason that sleep deprivation is an internationally recognized form of physical and mental torture — even in small doses, it feels like hell.