Dreaming Beyond Rem Sleep: Why And How?

Dreaming is a normal and healthy part of the sleep cycle, but why do dreams occur when we are not in REM sleep? Dreams can happen during any stage of sleep, but the vivid dreams that people tend to remember happen during REM sleep. During REM sleep, the brain is highly active and dreams are usually more elaborate and follow a narrative. Dreams during non-REM sleep tend to be more abstract. However, it's important to note that both REM and non-REM sleep are crucial for overall health and well-being. While REM sleep aids in learning, memory, and emotional processing, non-REM sleep is the time when the body repairs and regrows tissues, builds bone and muscle, and strengthens the immune system.

Dreaming occurs during all sleep stages, but REM sleep dreams are more vivid and memorable

Dreaming does occur during all sleep stages, but REM sleep dreams tend to be more vivid and memorable.

REM sleep, or rapid eye movement sleep, is the fourth of four sleep stages. During this stage, the eyes move rapidly, and brain activity increases. The brain activity during REM sleep is similar to the brain activity when a person is awake. Dreams typically occur during REM sleep, and they tend to be more vivid and memorable. Dreaming is considered normal and healthy, but frequent nightmares can interfere with sleep.

Non-REM sleep, or non-rapid eye movement sleep, is the first stage of sleep that a person enters. During this stage, the brain is not as active, and the body repairs and regrows tissues, builds bone and muscle, and strengthens the immune system. The non-REM stage of sleep is divided into three substages: light sleep, light sleep, and deep sleep.

While dreams occur during both REM and non-REM sleep stages, the dreams that occur during REM sleep tend to be more intense and memorable. This is because, during REM sleep, the brain is more active, and the dreams are often more vivid, fantastical, and bizarre. REM sleep dreams may also involve elements of waking life, but in a more distorted or fantastical way. In contrast, non-REM dreams tend to be more coherent and grounded in a specific time and place.

Additionally, the majority of REM sleep occurs during the second half of a normal sleep period. This means that dreaming is concentrated in the hours before waking up. This may also contribute to the increased memorability of REM sleep dreams, as they occur closer to the time of waking up.

Dreams during non-REM sleep tend to be more abstract and less narrative-driven

Dreaming during non-REM sleep is entirely possible. However, dreams during non-REM sleep tend to be more abstract and less narrative-driven than dreams during REM sleep.

REM sleep, or rapid eye movement sleep, is characterised by relaxed muscles, quick eye movement, irregular breathing, elevated heart rate, and increased brain activity. It is during this stage that most dreams occur. The brain activity during REM sleep is similar to its activity when a person is awake. Dreams during REM sleep are usually more vivid and elaborate, and they tend to follow a narrative.

Non-REM sleep, on the other hand, involves slower brain activity and deeper sleep. Dreams during non-REM sleep are more abstract and less story-like. A 2020 study found that participants who were woken up during non-REM sleep were more likely to report abstract dreams or "white dreams", where they could remember the feeling of dreaming but not the content.

While dreams during non-REM sleep may be more abstract, they can still be emotionally charged. Dreaming, in general, is thought to be the brain's way of processing emotions. Dreams can also occur during the transition phases between non-REM and REM sleep, which may further contribute to the abstract nature of non-REM dreams.

REM sleep is important for memory consolidation, emotional processing, and brain development

The rhythmic interactions in the theta band between the medial prefrontal cortex (mPFC) and limbic structures are thought to play a crucial role in processing emotional memories, including fear memories. The infralimbic cortex (IL) in the mPFC is thought to be critical in suppressing fear memories. During REM sleep, the strengthening of connections from the IL to the amygdala and the weakening of connections from the amygdala to the IL result in the suppression of fear expression cells associated with a given memory.

REM sleep is also important for brain development. Researchers hypothesize that REM sleep promotes brain development, as newborns spend most of their sleep time in this stage. Additionally, animals born with less developed brains, such as humans and puppies, spend more time in REM sleep during infancy than those with more developed brains, such as horses and birds.

Furthermore, REM sleep may aid in preparing the body for wakefulness. As the night progresses, we spend increasing amounts of time in REM sleep, which may explain why we are easier to wake up during this stage.

Dreaming may be the brain's way of processing emotions and clearing unnecessary information

Several contemporary theories of dreaming have been proposed, including the continuity theory, the emotion regulation theory, and the simulation theory. The continuity theory suggests that the emotional temperature of dreams will be positively associated with that of waking experiences. According to this theory, the content and affect of dreams mirror our daytime experiences and thoughts. For example, if we have a stressful day at work, we may have unpleasant dreams about work-related tasks that night and have similar feelings of stress the following day.

The emotion regulation theory of dreaming proposes that dreams play an active role in reprocessing and regulating waking affect. According to this theory, dreams provide a safe space to experience and process emotions, particularly negative ones. The simulation theory of dreaming also emphasises the active role of dreaming in emotional processing, positing that dreams serve to simulate threats and rehearse coping methods in a virtual context.

The current study aims to answer the question of whether dreaming plays a passive or active role in memory consolidation and emotion regulation by specifically addressing how the presence and content of dreams affect the prioritisation of emotional memories over neutral memories, as well as changes in valence and arousal ratings to negative stimuli overnight. The results of the study replicated the emotional memory trade-off, but only in those who reported dreaming (Dream-Recallers), and not in Non-Dream-Recallers. Results also replicated sleep-dependent reductions in emotional reactivity, but only in Dream-Recallers, not in Non-Dream-Recallers. Additionally, the more positive the dream report, the more positive the next-day emotional reactivity is compared to the night before. These findings implicate an active role for dreaming in overnight emotional memory processing and suggest a mechanistic framework whereby dreaming may enhance salient emotional experiences via the forgetting of less relevant information.

REM sleep paralysis prevents us from acting out our dreams

Dreaming is associated with the REM stage of sleep, which is characterised by relaxed muscles, quick eye movement, irregular breathing, an elevated heart rate, and increased brain activity. During this stage, your body experiences temporary muscle paralysis, known as muscle atonia, which prevents you from acting out your dreams.

Sleep paralysis occurs when you become conscious during the REM stage of sleep, finding yourself stuck between sleep phases. While sleep paralysis can be a standalone condition, it is often associated with other sleep disorders, such as narcolepsy, cataplexy, and hypnagogic hallucinations. It can also be triggered by factors such as stress, alcohol consumption, sleep deprivation, and certain medications.

During an episode of sleep paralysis, you may experience hallucinations, a feeling of suffocation, or a sense of an intruder in the room. These episodes can be frightening and may provoke a panic response. However, they typically only last from a few seconds to a few minutes, and you can safely wake someone up if they are experiencing sleep paralysis.

While there is no treatment to stop an episode of sleep paralysis once it has started, certain medications and improvements in sleep hygiene can help reduce the frequency of episodes. Maintaining a consistent sleep schedule, creating a comfortable sleep environment, and limiting the use of electronic devices before bed can all help to improve sleep quality and reduce the likelihood of sleep paralysis.

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