Mice fidget. Those motions have big effects on their brains

Extra movements may shape thinking, a study hints 

mice brains

In the brains of mice trained to do a job, nerve cell activity (shown) is more tightly linked to irrelevant body movements than to the job itself, researchers found.

A. Churchland

Survey any office, and you’ll see pens tapping, heels bouncing and hair being twiddled. But jittery humans aren’t alone. Mice also fidget while they work.

What’s more, this seemingly useless motion has a profound and widespread effect on mice’s brain activity, neuroscientist Anne Churchland of Cold Spring Harbor Laboratory in New York and colleagues report September 24 in Nature Neuroscience. Scientists don’t yet know what this brain activity means, but one possibility is that body motion may actually shape thinking.

Researchers trained some mice to lick a spout corresponding to an area where a click or a flash of light originated. To start their task, mice grabbed a handle and waited for the signal. As the mice focused on their jobs, researchers used several different methods to eavesdrop on nerve cell behavior in the animals’ brains.

All the while, video cameras and a sensor embedded on a platform under the mice picked up every move the rodents made — and there were a lot.

Mice wiggled their noses, flicked their whiskers and fiddled their hind paws while concentrating on finding the sound or light, the team found. Those fidgets showed up in nerve cell activity. When a whisker moved, for instance, nerve cells involved in moving and sensing sprang into action. Fidgets predicted a big chunk of neural behavior, mathematical models suggested. Mice’s fidgets even had stronger effects on brain activity than did the task at hand, the researchers report.

These movements reflect “unknown priorities of the animal,” the researchers write. One tantalizing possibility is that body motion — and its big effect on brain activity — may be part of the thinking process.

Laura Sanders

Laura Sanders is the neuroscience writer. She holds a Ph.D. in molecular biology from the University of Southern California.

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