What Is Lucid Dreaming?
From a scientific perspective, a lucid dream is a unique state of consciousness that occurs during sleep, when a person maintains self-awareness. During a lucid dream, not only can a person understand that they are dreaming, but they can also (to varying degrees) influence both the dream’s events and their own behaviors and emotional states.

How Is Lucid Dreaming Different from Regular Dreams?
Physiologically, lucid dreams occur during the REM phase of sleep, which is the phase when the brain’s activity resembles that of wakefulness and most vivid dreams occur. Polysomnographic measurements conducted by various researchers have confirmed this fact.