May 5, 2011 at 8:34 AM ET
Scientists may have found an explanation for all those slip-ups we make when we haven’t gotten enough sleep.
A new study shows that even when we feel wide awake, regions 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.
Though the study was in rats, its results should be applicable to humans, said Dr. Chiara Cirelli, a co-author on the study and an associate professor in the department of psychiatry at the University of Wisconsin at Madison.
When it comes to the mechanics of sleeping and waking brains, there isn’t a whole lot of difference between humans and rats, Cirelli said.
To learn what happens in the brains of the sleep deprived, Cirelli and her colleagues wired up the rats’ brains. By implanting electrodes in brain tissue the researchers would then be able to monitor what individual neurons were doing.
Some of the electrodes were positioned deep in the rats’ brains, which means that the experiment will be difficult to duplicate in humans.
The researchers kept the rodents awake long past their “bedtimes,” by dropping fun toys into the rats’ cages. Though they were tired, the rats would continue to play for hours with the novel toys.
As the rats played, the researchers watched what was happening in the rodents’ brains. What they saw surprised them: nerve cells would be sparking one minute and then go completely silent in a kind of nap phase.
You couldn’t tell this was happening by watching the rats playing -- they all looked perfectly normal. But subtle differences showed up when the researchers gave the rats a task to perform.
The rats had been taught to access sugar pellets by reaching through a hole in their cages with just one paw. Getting a pellet through the hole and into the cage takes a lot of concentration and dexterity, Cirelli said. Normally the rats would be able to do this over and over again, only rarely dropping a pellet.
But rats that were sleep-deprived had much less success getting the pellets into their cages. And when researchers watched what was happening in the rats’ brains, they saw that the mistakes happened when nerve cells went offline in the region that controls movement.
The rats weren’t consistently bad at what they were doing -- one minute they’d be able to pull a sugar pellet in and the next they’d slip up. And therein lies the danger of getting too little sleep, Cirelli said.
Think about driving – or air traffic controllers – she said. 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. And yet another reason to get your Zzzz’s.
Ever had any funny (or scary) slip-ups when your snooze-time was curtailed? Tell us about it, below.
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