REM Sleep
REM Sleep: Rapid Eye Movement — the sleep stage characterized by rapid eye movements. The majority of dreams occur during this phase. The brain is highly active while the body experiences temporary paralysis.
Related Terms
Sleep Cycle
A cycle of approximately 90 minutes consisting of NREM and REM stages, repeating 4-6 times per night. REM duration increases with each cycle, and dreams become more vivid.
Sleep Paralysis
A temporary condition where the body cannot move while consciousness is awake during sleep onset or awakening. May be accompanied by hallucinations and fear. Culturally associated with 'the nightmare' or incubus.
NREM Sleep
Non-REM sleep stages. Consists of three phases: light sleep, medium-depth sleep, and deep sleep. Dreams can occur in these stages but are typically less vivid and shorter.
Lucid Dream
A conscious dream state where the dreamer is aware they are dreaming and can sometimes direct the dream's flow. Studied from ancient Tibetan tradition to modern neuroscience.
Hypnagogic Imagery
Visual, auditory, or bodily hallucinations experienced during the transition between wakefulness and sleep. Associated with creative ideas and artistic inspiration.
Hypnopompic Imagery
A semi-dream state experienced during the transition from sleep to full wakefulness. The awakening version of hypnagogic imagery; dream remnants blend with reality.