“The witching hour… was a special moment in the middle of the night when every child and every grown-up was in a deep, deep sleep, and all the dark things came out from hiding and had the world all to themselves.”
-Roald Dahl, The BFG

In folklore and literature, the sleeping hours represent a state of heightened vulnerability, a time when the “ghoulies and ghosties, and long-leggedy beasties” roam free and wreak havoc. Today, neuroscientists are unraveling the biological underpinnings of nightmares, night terrors, and other sleep disturbances. 

Recently, I had the chance to sit down to discuss these nighttime phenomena with biologist H. Craig Heller, PhD, a member of the Stanford Neurosciences Institute and an expert in the neurobiology of sleep.