Bizarre Parasomnias and Sleep Disorders

Science reveals what happens when your sleeping, dreaming and waking worlds collide
Unlike nightmares, night terrors, which can cause someone to wake up screaming for no reason, occur in non-REM sleep when the brain is most quiescent. Your body activates the brain's amygdala (its fear center), triggering a fight-or-flight response.

French philosopher Gaston Bachelard wrote in 1960 that “sleep opens within us an inn for phantoms.” Recent research agrees, finding that some sleepers shriek or even gorge themselves without knowing it. These sleep-disorder sufferers experience neural glitches that mix conscious and unconscious states. Scientists are now searching for the physiological underpinnings in hopes of developing better drug therapies.

Launch our gallery of the most bizarre parasomnias here.

Instant Expert: Launch Your Quick and Easy Primer on Just About Everything at