Rem Sleep: Vital To Our Wellbeing And Daily Functioning

Sleep is a normal body process that allows your body and brain to rest. While it might seem as simple as closing your eyes and nodding off, sleep is anything but simple. In fact, modern medicine's understanding of sleep, what it does and how it works is just getting off the ground.

REM sleep is a phase of sleep where the eyes move frequently and rapidly under the eyelids. It was first identified in babies, and we now know that newborn mammals (including humans) spend most of their early lives in REM sleep. As humans develop and mature, the amount of REM sleep gets less and less and eventually levels out in early adulthood.

REM sleep is important for brain development and plays a role in memory consolidation, emotional processing, brain development, and dreaming. Most adults need about two hours of REM sleep each night.

REM sleep and brain development

REM sleep is thought to be important for brain development, particularly in infants and children.

REM sleep was first identified in babies

REM sleep and memory consolidation

REM sleep is important for memory consolidation, which is the process of storing new information in the brain. During REM sleep, the brain processes new learnings and motor skills from the day, committing some to memory, maintaining others, and deciding which ones to delete.

REM sleep is characterised by relaxed muscles, quick eye movement, irregular breathing, elevated heart rate, and increased brain activity. It is also when most dreams occur.

REM sleep makes up about 25% of total sleep time. The first cycle is usually the shortest, around 10 minutes, and each subsequent cycle is longer, up to an hour.

While the importance of REM sleep for memory consolidation is well-established, the specific mechanisms by which it occurs are still being studied. Some studies have shown that sleep deprivation can lead to memory consolidation issues, while others have shown that it does not have a significant impact.

It has been hypothesised that the high levels of brain activity during REM sleep may be involved in memory consolidation. This includes the replay of neuronal activity from waking learning episodes, which could be evidence of memory consolidation.

Additionally, the role of REM sleep in emotional processing may also be linked to its role in memory consolidation. REM sleep helps the brain process emotional memories, and dreams, which are more vivid during REM sleep, may also play a role in emotional processing.

REM sleep and emotional processing

REM sleep is important for regulating our emotions. During REM sleep, our brain processes emotional memories, including those associated with fear. This is supported by research which has shown that sleep deprivation increases negative emotional reactivity and diminishes positive reactions to positive events. REM sleep is also thought to play a role in our ability to cope with emotional stress in everyday life.

REM sleep and dreaming

REM sleep, or rapid eye movement sleep, is a phase of sleep where the eyes move frequently and rapidly under closed eyelids. It was first identified in human infants, who spend most of their early lives in this sleep stage.

During REM sleep, the brain remains highly active and dreams occur. The heart rate, blood pressure, and breathing increase to levels similar to when one is awake, and the body experiences temporary paralysis, which may be to prevent people from acting out their dreams.

REM sleep is thought to be important for several reasons. Firstly, it may aid in brain development, especially in newborns, who spend most of their sleep in this stage. Secondly, it is believed to facilitate the formation and consolidation of certain types of memories, particularly emotional ones. Thirdly, it may help with learning and memory by regulating neuronal synapses. Finally, it may also play a role in mood regulation and emotional processing.

Overall, REM sleep is a crucial aspect of sleep, and disruptions to this stage can have negative consequences on various aspects of health and daily functioning.

REM sleep and learning

REM sleep is vital for learning and memory consolidation. Research has shown that sleep does more than allow the brain to rest; it aids the consolidation of long-term memories. REM sleep and slow-wave sleep play different roles in this process. REM sleep is associated with the consolidation of nondeclarative (implicit) memories, such as procedural memories or tasks that we can do without consciously thinking about them, like riding a bike. Slow-wave sleep or non-REM (NREM) sleep, on the other hand, is associated with the consolidation of declarative (explicit) memories, which are facts that need to be consciously remembered, such as dates for a history class.

During REM sleep, the brain prunes its synapses, which are the spaces where brain cells communicate with one another. This process improves memory and problem-solving abilities. Studies have shown that a healthy sleep routine, including sufficient REM sleep, produces a significant learning-dependent performance boost. The idea is that sleep helps the brain edit its memory, looking for important patterns and extracting overarching rules, which can be described as 'the gist', and integrating this with existing memory.

The 'synaptic scaling' hypothesis suggests that REM sleep plays a crucial role in regulating learning that occurs while we are awake, enabling more efficient and effective storage in the brain by making better use of space and energy. Physiological studies have also shown that, aside from the occasional twitch, a person becomes temporarily paralysed during REM sleep, preventing them from acting out their dreams.

Research has also found that taking an afternoon nap increases learning capacity, with REM sleep facilitating the consolidation of nondeclarative memories. A study on rats revealed that cell assemblies that formed upon learning were more active during subsequent sleep episodes, providing further evidence of the link between sleep and learning.

In summary, REM sleep is essential for learning and memory consolidation, with studies demonstrating its role in enhancing memory performance and regulating learning that occurs while awake.

Frequently asked questions