Your brain is electric. Tiny impulses constantly race among billions of interconnected neurons, generating an electric field that surrounds the brain like an invisible cloud. A new study published online July 15 in Neuron suggests that the brain’s electric field is not a passive by-product of its neural activity, as scientists once thought. The field may actively help regulate how the brain functions, especially during deep sleep. Although scientists have long known that external sources of electricity (such as electroshock therapy) can alter brain function, this is the first direct evidence that the brain’s native electric field changes the way the brain behaves.