Humans spend 33% of their lives sleeping. Getting proper sleep is essential to living a healthy life. There are 2 types of sleep. They are REM(Rapid Eye Movement) and non-REM sleep. REM sleep is deep sleep that involves realistic, lucid dreams, while non-REM sleep is considered normal sleep.
In 1953 a German scientist who studies brain activity made a compelling discovery. While running tests on brain activity he noticed that the subject’s eyes were moving rapidly during sleep. The subject’s brain was active and the subject’s muscles were relaxed. There are several different names for this kind of sleep. It can be called REM(rapid eye movement) sleep, desynchronized sleeping, or paradoxical sleep. The reason it was also given the name “paradoxical sleep” is because the brain is active and eyes are moving, while the rest of the body is in a paralyzed state, creating a paradox.
Paradoxical or REM sleep occurs for about 90-20 minutes per night in adults. This makes up 20-25% of the sleep night. In infants REM sleep makes up about half of their sleep night. It happens in cycles 4 to 5 times throughout the night. REM sleep tends to happen at the end of sleep. How long a person stays in REM sleep, how often they enter REM sleep, and how early they enter REM sleep depends on where that person stands psychologically. For example, a person who is depressed will most likely be in the REM state longer than somebody else. It’s common to go into a lighter sleep or even wake up after exiting REM sleep. People who are sleep deprived tend to enter REM earlier than people who get proper sleep.
During REM sleep the muscles are in a state of paralysis. This is to protect ourselves and others. By our muscles being paralyzed we can’t act out our dreams. Not everyone experiences paralysis while in REM. It’s highly possible that they will act out their dreams and this could be potentially dangerous. This disorder is called REM behavioral disorder or RDB for short. People with RDB can remember their dreams in vivid detail, unlike those who experience paralysis during REM sleep. They are also at high risk of developing Parkinson’s disease or dementia later on in life.
Paradoxical sleep is the stage of sleep where lucid, strange dreams happen. Studies show that there are certain parts of the brain that are active during REM and other parts are not. The section of the brain responsible for emotions are highly active during sleep, which explains why we feel emotions during dreams. The part of the brain responsible for producing visual images is also highly active during dreams, which explains how we can see such vivid, realistic images during our dreams. During REM we have no control over the actions we take. That’s because that section and the section of the brain responsible for decision making are barely active at all during REM.
Neurons called REM sleep-on cells are active during REM sleep. These neurons serve as the catalyst for paradoxical sleep. The electrical and chemical activity that is responsible for REM sleep comes from the brain stem. The right and left brain very responsive during REM, especially when lucid dreams are happening.
There are theories that REM sleep is responsible for holding memories together. It is also theorized that REM sleep plays a role in brain development. This is supported by the fact that babies are in a state of REM sleep for half of the time they are asleep, and as humans get older they experience less REM sleep. This is because the brain develops more with age, and the more the brain is developed the less REM sleep is needed.
REM sleep and non-REM sleep are associated with different activities. non-REM sleep occurs at the beginning of sleep, while REM sleep occurs at the end of sleep. REM sleep improves the ability of the brain to think critically. This explains why it is harder to solve problems when there is a lack of sleep. It also increases spatial memory. Spatial memory has to do with a person’s ability to navigate and feel comfortable in a familiar place. Non-REM sleep improves declaritive memory, which has to do with long-term memory based on facts. That basically means remembering things as they actually happened rather than what is believed to have happened.