Here's a few ways a tired brain can affect an otherwise pleasant and productive human being: You can get extremely cranky; you will make a federal case out of the smallest annoyance. You can turn daffy; you will put the ice cream away in the cupboard instead of the freezer. You can become stupid - unable to solve even the simplest crossword puzzle clue. Or so I've been told by fed-up loved ones.
Todd Maddox, a psychology professor at the Institute for Neuroscience at the University of Texas in Austin, tries to understand what exactly is going wrong in the impaired brain, whether it is impaired by lack of sleep, normal aging or as a result of diseases like Parkinson's and Alzheimer's. "The brain regions that are impaired when you are sleep-deprived are the same ones that are impaired with aging," he says.
He'd also like to use that knowledge to find ways of improving the performance of people with chronically impaired brains or those who can become sleep deprived in high-pressure, life-and-death jobs, like doctors, firefighters and soldiers. One possibility: Something called neurorehabilitation, where people learn to teach unaffected parts of their brains to pick up tasks usually done by a part of the brain that is now not working so well.
Whether this research will help make over-tired reporters less cranky is still a distant hope.
To probe how impaired brains work, Maddox impairs them by depriving them of sleep. In a recent study, he and colleague David Schnyer, also of the University of Texas, tortured a group of West Point cadets as they tried to see how two distinct brain functions, information processing and information categorization, were affected by lack of sleep.
Maddox and Schnyer had the cadets do a task on a computer that forced them to use a part of the brain called the striatum, which is associated with non-conscious, implicit learning--information categorization. This is opposed to the frontal cortex, that gray matter that makes us human and allows the smartest versions of the species to prove Fermat's last theorem--information processing.
They were shown lines on a computer screen and told to put each in one of two groups according to instructions that didn't make much sense, like, "Which line is longer than its orientation."
"The best way to solve these tasks is to view hundreds of these lines--you have to gain experience," says Maddox. "You can't overthink it and come up with a verbal rule; you have to turn off the frontal cortex, stop thinking and go with your gut."
(They proved this little game worked by showing in earlier studies that people who were forced to occupy their frontal cortices with a complex task like counting backward from 100 by threes did better at the line game than people who had their entire brains at their disposal.)
The cadets worked on the task on a Saturday morning after getting a good night's sleep on Friday night. Some were then kept awake all night and forced to do it again on Sunday morning. Others, a control group, enjoyed a nice night of sleep before repeating the task.
What the researchers found is that the striatum seemed to be much less affected than the frontal cortex by the lack of sleep. Tired people who were able to keep their frontal cortices out of the way and let the more automatic striatum do its work were able to do almost as well on the task with no sleep.
There was a wrinkle, though. Some over-tired cadets who were able to relax and let the striatum take over on Saturday couldn't do it on Sunday. "We found people falling back on conscious verbal strategies when they were tired," he says. "They started drawing on these brain regions that were massively broken down."
When you are sleep-deprived, you can overthink things, and that's just when the part of the brain that does the overthinking is cooked. Clearly, says Maddox, some people were much more highly susceptible to sleep deprivation. What he'd like to know next is why. "What it is about them that makes them vulnerable so they fall back on control systems and perform poorly?" he wonders. "Another group of people were able to use automatic processes and performed well."
Maddox has no plans to probe crankiness, but the subject does interest him. "Some cadets handled it no problem; it was [as] if they hadn’t been sleep-deprived," he says. "And some came in and were cranky, cranky, cranky. It would have been interesting to know if the cranky ones did worse. Or better."