Sleep Science and REM Sleep Characteristics

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Questions and Answers

What characterizes REM sleep in terms of muscle activity?

Complete muscle paralysis (correct)

Twitching of muscles only

Increased muscle tone

Control over muscle movement

Which of the following EEG characteristics is associated with stage 2 sleep?

High amplitude, low frequency waves

K complexes and sleep spindles (correct)

Delta waves predominance

Theta waves only

What is the primary wave type present in stage 3 sleep?

Delta waves (correct)

Theta waves

Beta waves

Alpha waves

How does the time spent in different sleep stages change throughout the night?

Less time is spent in REM sleep as the night progresses Signup and view all the answers

What kind of stimuli can easily arouse a person from REM sleep?

Meaningful stimuli Signup and view all the answers

Which statement is true regarding the content of dreams recalled from REM sleep?

Dreams are usually stories rather than isolated experiences Signup and view all the answers

Which type of waves is characterized by bursts of 11- to 15-Hz waves occurring during stage 2 sleep?

Sleep spindles Signup and view all the answers

What typically happens after the initial cycle of sleep stages through stage 3?

Sleepers go back through the stages of sleep Signup and view all the answers

What characterizes the sleep cycles of most human adults?

They sleep only once per day. Signup and view all the answers

What effect does melatonin have when administered at the correct time?

It significantly reduces the adverse effects of jet lag and shift work. Signup and view all the answers

What is the role of the pineal gland in relation to sleep?

It secretes melatonin in response to signals from the SCN. Signup and view all the answers

Which condition is characterized by falling asleep around 7:30 PM and waking up at 4:30 AM?

Advanced sleep phase syndrome Signup and view all the answers

What can be inferred about the relationship between circadian genes and evolutionary history?

Circadian genes evolved early in evolutionary history. Signup and view all the answers

During which sleep state are levels of ACh in the hippocampus and neocortex highest?

REM sleep Signup and view all the answers

What is the relationship between the activity of noradrenergic neurons and sleep states?

Activity is high during wakefulness and low during slow-wave sleep. Signup and view all the answers

What does the term 'polyphasic sleep' refer to?

A sleep pattern of frequent naps throughout the day. Signup and view all the answers

What substance is released by astrocytes during increased brain activity, promoting sleep?

Adenosine Signup and view all the answers

Which sleep disorder is characterized by involuntary leg movements during sleep?

Periodic limb movement disorder Signup and view all the answers

What advantage is observed when adults are awakened during REM sleep and kept awake for 15 minutes?

They do not experience tiredness the next day. Signup and view all the answers

How does caffeine affect adenosine receptors?

It blocks them to prevent inhibition of neural activity. Signup and view all the answers

What is a common cause of insomnia according to the content?

Physician-created factors Signup and view all the answers

Which type of memory is primarily facilitated by slow-wave sleep?

Declarative memories Signup and view all the answers

What is the primary role of the hippocampus during sleep?

To support navigational learning during slow-wave sleep. Signup and view all the answers

Which type of sleep apnea is caused by a failure of the CNS to stimulate respiration?

Central sleep apnea Signup and view all the answers

What are zeitgebers?

Temporal cues in the environment that help synchronize circadian rhythms. Signup and view all the answers

What happens to adenosine during slow-wave sleep?

It gets destroyed. Signup and view all the answers

What phenomenon occurs when an individual's sleep-wake cycle and body temperature cycle break away from each other?

Internal desynchronization Signup and view all the answers

What characterizes obstructive sleep apnea?

Obstruction of the respiratory passages by muscle atonia. Signup and view all the answers

Fatal familial insomnia leads to what outcome?

Normal sleep patterns in midlife followed by a loss of sleep. Signup and view all the answers

During which type of sleep are specific patterns of hippocampus activation indicative of memory rehearsal?

Slow-wave sleep Signup and view all the answers

What happens to the average free-running period in humans when they are under conditions of constant illumination?

It increases to an average of 24.2 hours. Signup and view all the answers

What effect does jet lag have on circadian rhythms during east-bound flights?

It results in phase advances. Signup and view all the answers

What is primarily affected by both jet lag and shift work?

Sleep disturbances Signup and view all the answers

How long does it typically take to adjust to an 8-hour phase advance caused by jet lag?

8 days Signup and view all the answers

What role do zeitgebers play in adjusting the internal clock?

They help synchronize the internal clock to the external environment. Signup and view all the answers

What occurs if a person is exposed to bright light after the low point in their daily rhythm?

Their circadian rhythm is advanced. Signup and view all the answers

Where in the brain is the circadian clock primarily located?

Suprachiasmatic nuclei (SCN) Signup and view all the answers

What happens to the activity of noradrenergic neurons in the locus coeruleus (LC) during wakefulness?

It is high. Signup and view all the answers

What is the function of melanopsin in circadian rhythms?

It facilitates light information transfer to the SCN. Signup and view all the answers

Which type of neurons are mostly inactive during REM sleep?

Serotonergic neurons Signup and view all the answers

What ability is preserved in people who are blind but lose rods and cones?

They can still show normal circadian rhythms. Signup and view all the answers

What happens to circadian rhythm entrainment when SCN neurons are lesioned?

Entrainment by light is blocked, but not by food/water availability. Signup and view all the answers

What is the effect of electrical stimulation of the preoptic area?

It produces drowsiness and sleep. Signup and view all the answers

Which part of the hypothalamus is thought to promote wakefulness?

Posterior hypothalamus Signup and view all the answers

What occurs during REM sleep deprivation regarding penile erections?

They begin to occur during slow-wave sleep. Signup and view all the answers

How does the activity in the reticular formation affect sleep and wakefulness?

Low activity induces sleep. Signup and view all the answers

What happens if the preoptic area is destroyed?

Total insomnia. Signup and view all the answers

What is the role of the anterior hypothalamus in sleep regulation?

It suppresses arousal activity. Signup and view all the answers

Study Notes

Different Stages of Sleep

Sleep is categorized by patterns in EEG, EOG (eye movement), and EMG (muscle activity).
Synchronous EEG activity occurs when neurons fire together, creating large, clear waves.
Desynchronous EEG activity results from randomly firing neurons, making small chaotic waves.
Alpha waves (8-12 Hz) are present during quiet rest with eyes closed.
Beta waves (13-30 Hz) indicate active information processing and alertness.
Stage 1 sleep is characterized by low voltage, high frequency waves similar to alert wakefulness, but slower. Theta waves (3.5-7.5 Hz) start emerging. Hypnic jerks (muscle twitches) are common. Emergent stage 1 sleep has theta and beta activity, REMs, loss of muscle tone.
Stage 2 sleep displays higher amplitude, lower frequency waves than stage 1. K-complexes (sudden sharp waveforms) and sleep spindles (0.5-2s bursts of 11-15Hz waves) are hallmark features.
Stage 3 sleep (also called slow-wave sleep, SWS) is dominated by large, slow delta waves (1-2 Hz). It's the deepest stage of sleep, where loud noises are needed to wake someone up.
Stages cycle through a pattern. A night's sleep typically involves multiple cycles of these stages and REM (emergent stage 1).

Theories of Dreaming

Hobson's activation-synthesis hypothesis: Dreams arise from random brain activity during sleep that the cortex attempts to interpret.
Revonsuo's evolutionary theory: Dreams provide a way to simulate threatening situations, improving our responses in real life.
Protoconsciousness Hypothesis (Hobson): Dreams simulate various events, not just threatening ones, acting as a training ground for experiences.

Neurological Basis of Sleep

The suprachiasmatic nuclei (SCN) of the hypothalamus are the body's main circadian clock, detecting light and helping to entrain behaviors to a 24-hour cycle.
Melanopsin is a special photochemical helping the retina communicate with the SCN about lighting conditions.
Damage to the preoptic area can lead to insomnia in animals.
Orexin/hypocretin is a neuropeptide that promotes wakefulness.
Neurotransmitters like acetylcholine (ACh), norepinephrine, and serotonin show different activity levels across sleep stages.

Effects of Sleep Deprivation

Sleep-deprived individuals report increased sleepiness, negative affect, and poor performance on tasks needing sustained attention.
Executive functions (problem-solving, memory, decision-making) are more susceptible.
Performance on logical deduction tasks may not suffer much.
Microsleeps are brief periods of sleep that can occur during wakefulness, often preceded by sleep deprivation.

Sleep Disorders

Insomnia: Difficulty falling or staying asleep. Can be iatrogenic due to sleeping pills.
Sleep apnea: Breathing stops during sleep. Can be obstructive or central.
Hypersomnia: Excessive sleepiness. Examples include narcolepsy.
Narcolepsy: Characterized by excessive sleepiness, sleep attacks, cataplexy (muscle weakness), and other symptoms.
REM sleep behavior disorder (RBD): Paralysis during REM sleep is absent, causing acting out of dreams.
Restless legs syndrome (RLS): Urge to move legs, causing discomfort, typically at night.
Sleep-related eating disorder: Eating while asleep, often resulting in weight gain.
Night terrors (Pavor nocturnus): Episodes of intense fear, screaming, and sweating during sleep, typically in children.
Sleepwalking (somnambulism): Walking or performing other actions during sleep.

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Description

This quiz explores various aspects of sleep science, focusing on REM sleep and other sleep stages. Questions cover muscle activity during REM, EEG characteristics, the role of melatonin, and the significance of sleep cycles. Test your knowledge about the fascinating world of sleep and its different phases.