Your Idling Brain

Do you know what your brain is doing when it seems like it isn’t doing anything at all? First of all, some circuits must remain active to keep your heart pumping and your lungs working. But much of the rest of the brain continues to chug away as the mind naturally wanders through grocery lists, rehashes conversations and just generally daydreams. This activity has been dubbed the resting state and it’s important, if the amount of energy devoted to it is any indication. Blood flow to the brain during rest is typically just 5–10% lower than during task-based experiments. Neuroscientists have seen evidence that the networks the brain engages during a resting state appear to look a lot like those that are active during tasks and they are designing studies to help identify the purpose for mind wandering, daydreaming, and so on. As one researcher put it, whatever resting activity is doing, its existence certainly proves one thing, the brain only rests when it’s dead.