For decades, scientists have mapped attention, memory, language, and reasoning to separate brain networks — yet one big mystery remained: why does the mind feel like a single, unified system?

The default mode network (DMN) is a set of interconnected brain regions known to be most active when humans are awake but not engaged in physical activities, such as relaxing, resting or daydreaming.

Hormone levels fluctuate like the tides, ebbing and flowing according to carefully orchestrated cycles. These hormones not only influence the body, but can cross into the brain and shape the behavior ...