Hypnagogic experiences and imagery are thought to occur in humans during the transition state between the phases of consciousness known as wakefulness and sleep. In contrast hypnopompic experiences and imagery are thought to occur during the transition from sleep to wakefulness.

This wakefulness-sleep transition (WST) state has been described as a no mans land which involves both features of wakefulness , NREM and REM sleep.[1].This WST state is sometimes referred to simply as the hypnagogic state.