This trope is taken Up to Eleven in the ' Battle of the Planets ' episode. See the Rule of Cool entry below.
Sleep is not one homogeneous state, but rather a progression through various states with extremely unique characteristics. In total, there are five stages of sleep that can be readily distinguished from each other. In other words, sleep is not just sleep! Additionally, non-REM sleep can be subdivided into 4 sub-stages, distinguishable by levels of EEG a measurement for the bioelectric activity of the brain visible during polysomnographic recordings.
Each successive stage of non-REM sleep is indicative of a deeper sleep, with stage 1 as the lightest and stage 4 as the deepest. The sleep science community has more recently combined non-REM stages 3 and 4 into one stage, stage 3.
So a basic picture we get of sleep looks like this: See the more complex graph below But beyond this simplified view, there is much more that can be said about both the characteristics of these two types of sleep and the way we move between their distinct stages of sleep throughout the night.
This connection between REM sleep and dreaming was first made in by our own Dr. Dementas well as his fellow student Eugene Aserinsky and their teacher Nathaniel Kleitman.
The stages of sleep were first described in by Alfred Lee Loomis, an American also known for significant work in developing the radar. Loomis and his coworkers used EEG recordings to classify 5 different levels of sleep that they referred to using the letters A to E.
When Dement and Kleitman discovered that REM sleep was a distinct state init led them to reclassify the stages of sleep, separating REM from the other four stages of non-REM and giving us the model we use today. This is known as the scanning hypothesis.
The rapid eye movements for which REM sleep takes its name are a result of the brain trying to scan the events in the dream world.
This is known as the scanning hypothesis, and you can read about some very cool studies that were used to prove it on the REM sleep page here.
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In many ways these eye movements during REM sleep are entirely indistinguishible from the eye movements that occur during wakefulness. In both cases they are characterized by darting movements and binocularly synchronicity, meaning that both eyes move together.
There are also, however, features of eye movements during REM sleep that are not real similar at all to that of wakefulness. Namely, during REM sleep there is a lack of eye centering and fixation, which are essential to waking sight, but a presence of occasional slow, drifting movements that never occur during wakefulness.
In order to conjure a dream, as you might imagine, the brain has to be highly active. In waking life the brain perceives and reacts to the world around a person. During dreaming the brain is not only perceiving and reacting, but also creating the environment.
Thus, it makes sense that mental activity is very high during REM sleep. Brain activity during REM sleep is very comparable to activity during wakefulness, as evidenced in these EEG recordings showing very fast, quick waves in both states.
ASP actually happens to most people at least once during their lifetime, and for those who experience it frequently it can be quite alarming.
Another characteristic of REM sleep is paralysis. REM paralysis is achieved by the REM atonia system, which creates a blockage of final nerve pathways, essentially inhibiting directions to react given by the brain from reaching the muscles.
However, not every muscle group is paralyzed. The diaphragm functions to let us breathe, smooth muscle groups such as the urinary sphincter work, as do the eye muscles, which has given researchers much to study in REM sleep.
A wonderful simplification of this information, and a great way to think about REM sleep, is below: In fact, non-REM is characterized by continuous low-level muscle movements in the neck and jaw muscles.
The sleeper can also more commonly roll around and shift positions during non-REM, but movement is still typically very infrequent compared to wakefulness, as you might cunningly have imagined ;- This is to say nothing of the intriguing occurrences of such events as sleepwalking and sleep terrors though!
Throughout the night, your body progresses in and out of the stages of non-REM sleep, and each stage has its own very unique characteristics.
Stage 1 Stage 1 sleep is a transition period from wakefulness to the other 3 stages of non-REM sleep. It is of short duration, usually lasting only from 1 to 7 minutes.
Stage 1 sleep is characterized by low voltage, mixed frequency EEG, as well as some slow, rolling eye movements and some relatively higher EMG activity.
The brain activity is shown below in the following EEG recording. A sleep researcher can easily recognize stage 2 sleep because of the presence of sleep spindles and K-complexes in the EEG waves.
A sleep spindle is a rapid wax and wane of the EEG waves in a 1 to 2 second interval, while a K-complex is a large wax and wane of the wave that somewhat resembles a mountain. Stage 3 Stage 3 and stage 4 are similar and both fall into the category of slow wave sleep.
They are so named because of the high amplitude waves in the EEG. In order to qualify as stage 3 sleep, these slow waves must be present in no more than 50 percent of the epoch. The waves are also referred to as delta waves.
Stage 4 Stage 4 is the other slow wave sleep period.Rapid eye movement sleep (REM sleep, REMS) is a unique phase of sleep in mammals and birds, distinguishable by random/rapid movement of the eyes, accompanied with low muscle tone throughout the body, and the propensity of the sleeper to dream vividly.
Jul 29, · Early studies of the echidna led to the conclusion that this monotreme did not have rapid eye movement (REM) sleep.
Because the monotremes had diverged from the placental and marsupial lines very early in mammalian evolution, this finding was used to support the hypothesis that REM sleep evolved after the start of the mammalian line. Rapid eye movement (REM) sleep was discovered by Aserinsky and Kleitman in 1 These workers reported that REM sleep was characterized by the periodic recurrence of rapid eye movements, linked to a dramatic reduction in the amplitude of the electroencephalogram (EEG) from that of the higher-voltage activity of the previous NREM sleep period.
Rapid eye movement sleep: Rapid eye movement sleep (REM) sleep is the portion of sleep when there are rapid eye movements (REMs).. Dreams occur during REM sleep. We typically have 3 to 5 periods of REM sleep per night. They occur at intervals of hours and are quite variable in length.
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