Sleep Paralysis and Stages of Sleep

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Questions and Answers

What role does paralysis play during REM sleep?

To facilitate deep NREM sleep

To enhance muscle tone during dreams

To allow the body to move freely

To protect the body from the mind's dreams (correct)

How often does the NREM to REM sleep cycle occur in humans?

90 minutes (correct)

30 minutes

60 minutes

120 minutes

Which of the following best describes the brain wave activity during awake status?

Moderately fast and synchronized

Slow and desynchronized

Slow and synchronized

Fast and desynchronized (correct)

What happens to muscle tone during stage 2 NREM sleep?

It is greatly reduced Signup and view all the answers

What are sleep spindles associated with in NREM sleep?

Higher amplitude brain waves Signup and view all the answers

What is the frequency of brain waves during slow wave sleep (Stage 3 and 4 NREM)?

1-4 Hz Signup and view all the answers

What characterizes the eyes during stage 3 + 4 NREM sleep?

No eye movements Signup and view all the answers

What change occurs in brain wave activity as a person transitions from NREM to REM sleep?

Increases in frequency and desynchronization Signup and view all the answers

What distinguishes REM sleep in the evolutionary context of reptiles, birds, and mammals?

REm sleep evolved separately in birds and mammals. Signup and view all the answers

Which of the following statements is true about the original stage of sleep in evolution?

NREM sleep is the original stage of sleep. Signup and view all the answers

What is a potential function of REM sleep related to body temperature?

It aids in metabolic regulation and thermoregulation. Signup and view all the answers

How do the sleeping habits of the !Kung people contrast with modern Western practices?

The !Kung sleep on hard surfaces while Westerners have soft mattresses. Signup and view all the answers

What is a key characteristic of sleep patterns observed in most pre-industrial hunter-gatherer tribes?

They engage in frequent afternoon naps of 30-60 minutes. Signup and view all the answers

Which neurotransmitter is NOT critical for controlling sleep?

GABA Signup and view all the answers

Where do the neuromodulators critical for sleep originate?

The brain stem Signup and view all the answers

What happens to acetylcholine levels during NREM sleep?

Acetylcholine levels decrease significantly. Signup and view all the answers

What was observed about children who took afternoon naps compared to those who did not?

They performed better on tests after napping. Signup and view all the answers

What does a higher density of NREM sleep spindles imply for a child's memory?

It leads to a greater improvement in memory retention. Signup and view all the answers

How long after a normal night of sleep did the performance differences in napping persist?

24 hours after sleeping. Signup and view all the answers

What role do sleep spindles potentially play in memory function?

They serve as a file transfer mechanism to aid memory storage. Signup and view all the answers

Can naps enhance learning according to the discussions presented?

They can enhance both memory and learning. Signup and view all the answers

What is the primary function of Process S in sleep regulation?

To regulate NREM sleep Signup and view all the answers

What effect does a night of sleep deprivation have on sleep patterns?

Increases sleep pressure and NREM sleep Signup and view all the answers

Which of the following statements about circadian rhythms is correct?

They can be influenced by external factors known as zeitgebers Signup and view all the answers

What is REM rebound?

An increase in REM sleep following sleep deprivation Signup and view all the answers

Which part of the brain is primarily responsible for controlling sleep timing?

Suprachiasmatic Nucleus (SCN) Signup and view all the answers

What characteristic distinguishes REM sleep from other sleep stages?

It is associated with increased brain activity Signup and view all the answers

What conclusion can be drawn from the persistence of circadian rhythms in the absence of external cues?

They are innate biological processes that guide behavior Signup and view all the answers

How does the evolution of REM sleep in birds and mammals illustrate evolutionary adaptation?

Birds and mammals have developed REM sleep independently Signup and view all the answers

What effect did taking a nap after the lecture have on students' memory performance over time?

It helped maintain higher memory performance for several days. Signup and view all the answers

What was the main finding of students’ performance at the 5-day test after taking a nap?

Both groups performed equally well on the 5-day test. Signup and view all the answers

What percentage decrease in performance did non-nap students experience one day after the lecture?

83% Signup and view all the answers

Why was the impact of napping on students' memory not verified?

Researcher did not confirm whether students actually napped. Signup and view all the answers

How did napping relate to students' overall learning at school according to the findings?

Napping can enhance learning and memory retention. Signup and view all the answers

What change occurs in the sleep patterns as individuals age, according to ontogeny?

Amount of total sleep decreases. Signup and view all the answers

Which group performed equally well in the immediate test after the lecture regardless of napping?

All students tested immediately. Signup and view all the answers

What is a common misconception about the impact of napping following a learning session?

Napping only benefits students who are sleep-deprived. Signup and view all the answers

Study Notes

Sleep Paralysis

Sleep paralysis is a phenomenon where the body is unable to move or speak during sleep.
The purpose of sleep paralysis is to prevent individuals from acting out their dreams.
NREM (Non-Rapid Eye Movement) and REM (Rapid Eye Movement) sleep were only discovered in 1953 by Nathaniel Kleitman and Eugene Aserinsky.

Sleep Stages and Their Characteristics

The NREM → REM sleep cycle lasts approximately 90 minutes in humans.
Deeper NREM (slow wave sleep) stages occur earlier in sleep, while REM sleep occurs later in sleep.

Stage 1 NREM

Eyes: Open with blinks, high-frequency brainwaves, low amplitude
Brainwaves: Alpha waves (8-12 times/sec or 8-12Hz)
Muscle: Strong muscle tone

Stage 2 NREM

Eyes: Slow rolling eye movements
Brainwaves: Theta waves (4-7 times/sec or 4-7Hz), higher amplitude, more synchronized
Muscle: Lowered muscle tone
Special events: K-complexes and sleep spindles

Stage 3 + 4 NREM (Slow Wave Sleep)

Eyes: No eye movements
Brainwaves: Delta waves (1-4 times/sec or 1-4Hz), very slow, high amplitude
Muscle: Further reduction in muscle tone

Sleep Regulation

Processes C and S regulate sleep:
- Process C is regulated by circadian clocks and melatonin, influencing NREM < REM sleep.
- Process S regulates NREM sleep and is the priority stage of sleep.
- Sleep deprivation leads to increased sleep pressure, resulting in increased NREM sleep.

REM Rebound

When REM sleep is deprived, the amount of REM sleep increases in subsequent nights.

Circadian Rhythms

Circadian rhythms are 24-hour biological cycles that regulate various bodily functions.
Zeitgebers are external cues, like light and dark, that influence circadian rhythms.
Circadian rhythms help regulate the sleep/wake cycle.

Evolutionary History of Sleep

All living species exhibit a 24-hour circadian rhythm.
Jean Jacque d'Orto de Mairan (1729) studied the leaf movements of heliotrope plants to demonstrate the persistence of circadian rhythms in the absence of external cues.
Sleep exists in all animals. However, only birds and mammals experience full-blown REM sleep, suggesting it evolved independently in both lineages.
This suggests that NREM sleep is the original stage of sleep, while REM sleep evolved later.

Function of REM Sleep

REM sleep may be related to thermoregulation and metabolic regulation.
The !Kung, a group of hunter-gatherers, exhibit a biphasic sleep pattern with afternoon naps.

Sleep During the Day

Humans experience a biologically hardwired dip in alertness in the middle of the day.
Afternoon naps can improve memory and cognitive performance.
Naps can help consolidate information learned during the day, leading to improved recall several days later.

Brain Mechanisms of Consciousness

Three critical neurotransmitters for controlling sleep: acetylcholine (Ach), noradrenaline (NA), and serotonin (5-HT).
These neurotransmitters are released from the brainstem.

Neurochemicals and Sleep Stages

Active wake: High levels of Ach, NA, and 5-HT
Quiet wake: Lower levels of Ach, NA, and 5-HT
NREM: Lower levels of Ach, NA, and 5-HT, except serotonin stays relatively high
REM: High levels of Ach, low levels of NA and 5-HT

Changes in Sleep Across the Lifespan (Ontogeny)

Sleep patterns and the WAKE:NREM:REM ratio change throughout life.
Children have a higher NREM to REM ratio compared to adults, with more deep REM sleep.
Total amount of sleep decreases with age.

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Description

Explore the fascinating phenomenon of sleep paralysis and the various stages of sleep. This quiz covers NREM and REM cycles, their characteristics, and how they affect our sleep patterns. Test your knowledge about the science of sleep and its stages.