Moods And Sleep: Rem Vs Nrem

Sleep is a complex and mysterious process that humans spend about one-third of their lives doing. A good night's sleep is essential for our health, mood, and overall well-being.

During sleep, our brain cycles through four stages: three non-rapid eye movement (NREM) stages, followed by a rapid eye movement (REM) stage. Each stage has a unique function and plays a role in maintaining our brain's overall cognitive performance.

NREM sleep is characterised by slower brain waves, reduced heart rate, and relaxed muscles. The first stage is a transition period between wakefulness and sleep, where we can be easily awakened. In the second stage, we become less aware of our surroundings, and our body temperature drops. The third stage is deep sleep, where our body repairs tissues, builds bone and muscle, and strengthens our immune system.

Following NREM sleep, we enter REM sleep, which is characterised by rapid eye movements and increased brain activity. Our body is temporarily paralysed during this stage, preventing us from acting out our dreams. REM sleep is important for learning, memory, and emotional processing.

The duration and quality of each sleep stage can be affected by various factors, including stress, lifestyle choices, sleep environment, irregular sleep schedules, health issues, age-related changes, diet, exercise, and the use of electronic devices.

Understanding the sleep cycle and its stages can help us recognise the importance of both the quantity and quality of sleep for our overall health and well-being.

Dreaming and memory consolidation

Dreams typically occur during REM sleep, when the brain is highly active and the body is temporarily paralysed. Dreaming is thought to be a way for the brain to process emotions and emotional memories. Dreaming is most common in the final stage of the sleep cycle, when the brain is highly active and the body is temporarily paralysed.

Memory consolidation also occurs during REM sleep. This is when the brain gathers, processes, and filters new memories acquired during the day. REM sleep is important for learning and memory, and non-REM sleep is when the body repairs and regrows tissues.

During NREM sleep, the brain produces bursts of rapid, rhythmic brain wave activity known as sleep spindles, which are thought to be a feature of memory consolidation. Sleep spindles are important for memory consolidation, and individuals who learn a new task have a significantly higher density of sleep spindles than those in a control group.

Memory consolidation also occurs during NREM sleep stage 3, when the brain consolidates declarative memories, such as general knowledge, facts or statistics, and personal experiences.

The sleep cycle includes both NREM and REM sleep, and both are important for memory consolidation. While NREM sleep is important for the consolidation of declarative memories, REM sleep is important for the consolidation of emotional memories.

REM sleep and negative self-concept

REM sleep has been found to contribute to the core features of cognitive dysfunction in anxious depression, including negative self-appraisals. A study by McNamara et al. (2010) found that self-appraisals of depressed/anxious participants were significantly more negative after awakenings from REM sleep compared to NREM sleep. This finding suggests that REM sleep may play a role in the negative self-concept observed in individuals with anxious depression.

The study included 35 healthy college students and 20 depressed/anxious students who were awakened during REM and NREM sleep episodes. After each awakening, participants completed tasks assessing their mood, memory, and self-appraisal. The results showed that depressed/anxious participants had more negative self-appraisals and recalled more negative memories after being awakened from REM sleep.

The study also found that REM sleep dreams in depressed/anxious participants were associated with greater frequencies of negative emotion, aggression, and victimization rates compared to dreams during NREM sleep. These findings suggest that REM sleep may facilitate the cognitive distortions associated with anxious depression.

Furthermore, the study suggested that REM sleep mechanisms may differentially impact the content or cognitions that occur in anxious depression. The results have clinical implications as REM-related indices and poor self-concept are predictors of mood dysfunction and suicidal ideation in individuals with depression.

While the study provides valuable insights into the relationship between REM sleep and negative self-concept in anxious depression, it is important to note that the participants were not clinically diagnosed with depression and were mostly college students. Therefore, the results may not be generalizable to older clinical populations.

Further research is needed to understand the complex relationship between REM sleep and self-concept, especially in clinical populations with depression and anxiety disorders.

REM sleep and negative emotions

REM sleep is associated with negative emotions and the processing of emotional experiences. During REM sleep, the brain is active and dreams typically occur. Research has shown that REM sleep is important for regulating emotions and that a lack of REM sleep can cause trouble coping with emotions.

REM sleep is believed to stimulate areas of the brain that help with learning and memory. During this stage, the brain repairs itself, processes emotional experiences, and transfers short-term memories into long-term memories.

Selective REM sleep suppression has been found to increase general negative affect and enhance amygdala responses. A study by Glosemeyer et al. found that lower amounts of REM sleep across all participants were associated with higher levels of general negative affect the next morning.

Another study found that REM sleep contributes to core features of cognitive dysfunction in anxious depression, including negative self-appraisals, biased memory processing, and unpleasant dream content. The study found that REM sleep differentially impacts the content or cognitions that occur in anxious depression, with a more potent depressogenic effect.

The way an individual copes with emotional stress or regulates their emotions may also modulate the effects of emotional stress on sleep. Experiential emotion regulation strategies, such as focusing on and expressing actual emotional feelings, have been found to promote efficient recovery from emotionally negative situations and have positive effects on sleep.

REM sleep plays a crucial role in regulating emotions and processing emotional experiences. A lack of REM sleep or REM sleep suppression can lead to increased negative emotions and affect the way individuals cope with emotional stress. Experiential emotion regulation strategies can help mitigate the detrimental effects of emotional stress on sleep.

REM sleep and aggression

REM sleep is the stage of sleep where most dreams occur. During this stage, the brain is highly active and resembles brain activity when awake. While the brain is aroused with mental activities during REM sleep, the body is temporarily paralysed, preventing sleepers from acting out their dreams.

REM sleep behaviour disorder (RBD) is a condition where this paralysis does not occur, enabling people to physically act out their dreams. RBD is relatively rare, affecting less than 1% of the population, and typically starts after the age of 50. It is often associated with other neurological conditions, such as Parkinson's disease, Lewy body dementia, and multiple system atrophy.

People with RBD may exhibit violent behaviours during sleep, such as shouting, punching, kicking, and jumping out of bed. These actions can put themselves and their bed partners at risk of physical injury. RBD has been linked to violent behaviours and aggression, with some patients reporting dreams about being chased or attacked, which they then unknowingly enact in real life.

Studies have found that RBD is more common in men and is often associated with dream enactment. One study reported that 79% of participants with RBD recalled vivid dreams, and 31% had hurt themselves or someone else. Another study found that RBD was more frequent in subjects younger than 35 years old.

Treatment for RBD typically involves a combination of lifestyle changes, medication, and injury prevention techniques. Melatonin is usually the first-line medication due to its fewer side effects and safety for elderly individuals. Creating a safe sleep environment is crucial, as sleep-related injuries have been reported in up to 81% of individuals with RBD.

REM sleep and emotional processing

REM sleep is important for emotional processing and plays a vital role in our overall health. During REM sleep, the brain processes information and emotions from the day, playing a vital role in learning and memory.

REM sleep is characterised by rapid eye movement, increased brain activity, and temporary muscle paralysis, which prevents us from acting out our dreams as they’re happening. Dreaming occurs during this stage, and dreams are often emotionally charged.

REM sleep is a deep sleep phase, but our brain waves are as active as when we're awake. In adults, REM sleep makes up about 20-25% of the sleep cycle. The final REM stage is the longest, lasting up to an hour.

During REM sleep, the brain's limbic system, which is involved with emotions, is active. This is when the brain processes emotions and emotional memories.

REM sleep deprivation can cause trouble coping with emotions.

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