Non-rapid eye movement sleep
NREM Sleep Stages – NREM sleep was divided into 4 stages in 1968, reduced to 3 in 2007. – Stage 1: Slow eye movement at […]
NREM Sleep Stages
– NREM sleep was divided into 4 stages in 1968, reduced to 3 in 2007.
– Stage 1: Slow eye movement at the beginning of sleep.
– Stage 2: No eye movement, rare dreaming, and sleep spindles.
– Stage 3: Deep sleep with more common dreaming and parasomnias.
– SWS dreams in Stage 3 are less vivid than REM dreams.
Physiological Aspects of NREM Sleep
– Sleep spindles are unique to NREM sleep and involve brain activation.
– K-complexes are single long delta waves unique to NREM and can be induced by transient noises.
– Inhibition of respiratory muscles during NREM sleep.
– Muscle movements during NREM sleep, including upper airway collapse leading to snoring and sleep apnea.
NREM Sleep and Memory
– NREM sleep aids memory consolidation, particularly declarative memory.
– SWS is crucial for memory consolidation.
– Working model of sleep and memory stabilization, including theta and gamma waves, and the role of sleep spindles.
Polysomnography and Slow-Wave Sleep
– Polysomnography (PSG) is used to study sleep, highlighting NREM stages 1, 2, and 3.
– Slow-wave sleep (SWS) is the deepest stage of NREM with the highest arousal threshold.
– SWS is crucial for memory consolidation and active rather than quiescent.
Research and Studies on NREM Sleep
– Structural differences between REM and NREM dream reports.
– Studies on NREM sleep deprivation and its effects on memory and EEG activity.
– Language learning during sleep, memory reactivation, and the role of sleep spindles.
– Evolutionary origins of distinct NREM and REM sleep stages, and the impact of sleep deprivation on sleep patterns.
Non-rapid eye movement sleep (NREM), also known as quiescent sleep, is, collectively, sleep stages 1–3, previously known as stages 1–4. Rapid eye movement sleep (REM) is not included. There are distinct electroencephalographic and other characteristics seen in each stage. Unlike REM sleep, there is usually little or no eye movement during these stages. Dreaming occurs during both sleep states, and muscles are not paralyzed as in REM sleep. People who do not go through the sleeping stages properly get stuck in NREM sleep, and because muscles are not paralyzed a person may be able to sleepwalk. According to studies, the mental activity that takes place during NREM sleep is believed to be thought-like, whereas REM sleep includes hallucinatory and bizarre content. NREM sleep is characteristic of dreamer-initiated friendliness, compared to REM sleep where it is more aggressive, implying that NREM is in charge of simulating friendly interactions. The mental activity that occurs in NREM and REM sleep is a result of two different mind generators, which also explains the difference in mental activity. In addition, there is a parasympathetic dominance during NREM. The reported differences between the REM and NREM activity are believed to arise from differences in the memory stages that occur during the two types of sleep.