Over the past few years, there has been growing interest in something called “resting state functional MRI”, a technique for seeing what your brain is doing when you aren’t doing much of anything at all. It turns out that brains at rest are pretty restless, consuming far more energy than they do when doing. More interesting, “resting” activity is not random, but highly coherent, consistent, and predictable. The discovery of the brain’s characteristic resting behavior led some years ago to the postulation of a “default network” for the brain–a set of regions that consistently cooperate to do … well, what, exactly, we don’t know. But surely it must be something interesting. Your brain would hardly waste all of that energy dancing to the beat of its inner drummer if there weren’t some reason for it, right?