1. Multiple neuroscience studies on insomnia identified a critical pattern: the brain's default mode network — responsible for self-referential thinking, planning, and rumination — fails to quiet down at bedtime in people experiencing sleep problems. Researchers consistently found hyperactivity in this network when it should have been winding down for sleep. 2. Here's the trap: the DMN is supposed to deactivate at night. But for people carrying cognitive overload, it can't. Your brain learned th