Rodent of the Week: The brain takes micro naps

We’ve all had them, and scientists now know what brain glitches look like. Certain parts of the brain can briefly shut down while the rest of the brain is functioning, a new study shows. These micro naps may help explain why people sometimes do mindless things, like leaving the key in the front door.

Researchers at the University of Wisconsin conducted an experiment with rats to explore the phenomenon of micro sleep. The longstanding theory has been that any momentary loss of consciousness affects the entire brain. But that is not what the scientists found. They inserted probes into specific groups of neurons in the brains of rats. The rats were then kept awake for long periods of time to produce sleep deprivation. Even while the rats were obviously awake and active, the probes showed that portions of the brain were asleep. During a task, the sleep-deprived rats started to make mistakes.

The study shows that even before falling asleep, certain groups of neurons in the brain are already going offline, the lead author of the study, Dr. Chiara Cirelli, a professor of psychiatry, said in a news release.

“This activity happened in a few cells,” Cirelli said. “For instance, out of 20 neurons we monitored in one experiment, 18 stayed awake. From the other two, there were signs of sleep -- brief periods of activity alternating with periods of silence.”

The study, published Wednesday in the journal Nature, supports the advice to halt certain activities, such as driving, when someone realizes he or she is sleepy.

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