The default network: your mind, on its own time

Studies about the brain usually focus on neural activity during the completion of a specific task-remembering a series of words, for example. But over the last 20 years, researchers have been interested in what the brain does during periods of supposed inactivity. They discovered that when someone appears to be doing nothing at all, a network of brain regions-named the default network-is hard at work, allowing for the rich inner lives inside our heads. Applying what is known about the default network to diseases like Alzheimer's allows for new possibilities for diagnosis and evaluation of treatments.