REM sleep plays a crucial role in emotional recovery, with studies showing that 60% of participants experience REM rebound after deprivation. Historical discoveries by pioneers like Aserinsky and Kleitman established its unique characteristics, including a blend of brain activation and muscle atonia. The review emphasizes REM sleep homeostasis and its periodicity within ultradian rhythms. It also explores the complex relationship between arousals, sleep, and consciousness, highlighting notable distinctions between non-REM and REM sleep-related arousals, revealing their similarities to wakefulness.
A 7-year history of vivid, immersive dreaming perceived as continuous with waking life, accompanied by persistent dream-reality confusion, is described in a younger individual. The patient engaged in reality-testing behaviors and reported significant cognitive fatigue. Video-polysomnography confirmed REM sleep without atonia and a dream re-enactment episode. Neuropsychiatric evaluation ruled out dissociative or psychotic disorders, and no neurodegenerative disease was observed. The case suggests a potentially distinct, non-neurodegenerative REM parasomnia phenotype, highlighting the need to expand current classifications to capture cognitive and metacognitive dimensions of REM sleep disorders. Potential mechanisms involving melanin-concentrating hormone signaling are discussed.
Dreaming is an involuntary cognitive process that occurs during sleep. While dreams have been studied since ancient times and became important in psychoanalysis, scientific research accelerated after the discovery of rapid eye movement (REM) sleep in the 1950s. This review brings together current findings on the neurobiological and psychological aspects of dreaming, covering what affects dream recall and content, the brain activity associated with dreaming, experimental models used to study dreams, and what these insights mean for clinical practice.