Probing Question: What is a lucid dream?

By Nick Bascom - Research/Penn State Have you ever had a dream that just didn't feel like a dream - where, like Alice in Wonderland, you had trouble telling fiction from reality? Perhaps you even felt like you had control over what was happening, as if you were directing a film produced entirely in your imagination. If so, you most likely experienced what sleep scientists like Edward Bixler call a "lucid dream." Bixler, a professor of psychiatry at Penn State Milton S. Hershey Medical Center who specializes in the electrophysiology of sleep and sleep disorders, says lucid dreams occur "when a person recognizes he or she is dreaming while in a dreaming state and often manipulates events within the dream." This is different from "dream recall," simply remembering a dream after you wake up. In order to distinguish between these states, says Bixler, it's important to understand the two basic stages of sleep: rapid eye movement, or REM; and non-rapid eye movement, or NREM. REM sleep is considered deep sleep and only accounts for about a quarter of sleep time. NREM is the longer, lighter stage of sleep. Although it was once believed that dreaming could take place only during REM sleep, recent studies suggest otherwise. Subjects awakened from NREM sleep often recall still images from their dreams, explains Bixler, but in order to dream in "live action," a sleeper must reach the REM stage.