Sleep Measurement and Polysomnography

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Questions and Answers

What aspect of the hippocampus is most directly associated with its function?

Memory formation (correct)

Logical reasoning

Complex visual processing

Emotional regulation

How do zeitgebers impact human chronotype variation?

They create fluctuations in sleep patterns. (correct)

They have no significant influence.

They stabilize circadian rhythms across all environments.

They exclusively affect older adults.

What finding was reported regarding the effect of napping on infants' memory?

Napping has no effect on memory retention in infants.

Naps only improve memory if combined with nighttime sleep.

Infants remembered less if given a nap.

Infants showed significant learning only if they napped after learning. (correct)

Which of the following best explains the Sentinel Hypothesis?

Awake individuals can provide a defense against predators. Signup and view all the answers

What was the outcome of the study regarding naps for middle school students?

Students who napped after a lecture showed improved memory retention. Signup and view all the answers

What correlation was found between NREM sleep spindles and memory recall?

Increased spindle density led to better memory recall. Signup and view all the answers

What memory task did preschool children perform in the study assessing naps?

Spatial location memory on a grid. Signup and view all the answers

What was concluded about the effect of naps taken shortly after learning?

They provide a protection against memory decay over time. Signup and view all the answers

How does chronological age impact chronotype according to recent findings?

Chronotype generally becomes earlier as individuals age. Signup and view all the answers

What aspect of sleep spindles may enhance memory function?

They serve as a file transfer system for memory consolidation. Signup and view all the answers

What happens to the total amount of sleep as individuals age?

Total sleep decreases Signup and view all the answers

At what stage of life does the sleep pattern typically shift to monophasic sleep?

10 years old Signup and view all the answers

Which process in the two-process model is related to the buildup of adenosine?

Process S Signup and view all the answers

What is the main effect of caffeine on the sleep process?

Blocks the signal of adenosine Signup and view all the answers

What characterizes the sleep of infants compared to adults?

Highly polyphasic sleep Signup and view all the answers

During which age range does the child typically exhibit the greatest amount of slow wave sleep?

Around age 7 Signup and view all the answers

What notable change occurs in sleep patterns for the elderly around the age of 75?

Reduced REM sleep Signup and view all the answers

How does the pattern of sleep change as children transition from newborn to toddler stages?

From polyphasic to biphasic sleep Signup and view all the answers

How does sleep deprivation impact feelings of well-being in relation to Processes C and S?

Increases the gap between Process C and S Signup and view all the answers

What effect does REM sleep typically have on problem-solving abilities?

It allows for faster recognition of patterns Signup and view all the answers

What is a distinguishing feature of bird sleep cycles compared to mammal sleep cycles?

Unihemispheric sleep during REM Signup and view all the answers

How do reptiles differ from birds and mammals in terms of sleep?

Most studies show reptiles exhibit no REM sleep. Signup and view all the answers

What is the primary role of acetylcholine during REM sleep?

Activation of electrical brain power Signup and view all the answers

Which neurotransmitter is primarily associated with active wakefulness?

Acetylcholine Signup and view all the answers

In terms of sleep patterns, what is unique about the behavior of the White-crowned Sparrow?

It is being studied for potential methods to skip sleep. Signup and view all the answers

What physiological state is NOT observed in birds during NREM sleep?

Consistent eye closure Signup and view all the answers

During REM sleep, which of the following occurs in the brain?

Visual centers and memories are activated Signup and view all the answers

Which hunting-related behavior is associated with the sleep patterns of the !Kung tribe?

Collective sleeping and afternoon naps Signup and view all the answers

What is a critical role of the thalamus during wakefulness?

Gates sensory information to the cortex Signup and view all the answers

Which of the following sleep stages is primarily characterized by the absence of serotonin and noradrenaline?

REM sleep Signup and view all the answers

What evolutionarily significant conclusion can be drawn about REM sleep?

It evolved concurrently in birds and mammals. Signup and view all the answers

What does the presence of PGO waves during REM sleep indicate?

Bursts of electrical activity related to dreaming Signup and view all the answers

During which sleep phase does the brainstem partly activate while the cortex is less logical?

REM sleep Signup and view all the answers

Which neurotransmitter is least active during REM sleep?

Serotonin Signup and view all the answers

What is the main difference in muscle tone during REM sleep between birds and mammals?

Birds do not lose muscle tone consistently during REM sleep. Signup and view all the answers

Which type of sleep is characterized by a significant increase in muscle tone and synchronized brain waves?

Stage 2 NREM Signup and view all the answers

What physiological measurement is often considered the gold standard for analyzing sleep stages?

Polysomnography (PSG) Signup and view all the answers

Which process is primarily responsible for regulating alertness and arousal within the Two Process Model of sleep?

Process C Signup and view all the answers

What is the primary zeitgeber that helps synchronize internal biological clocks?

Light Signup and view all the answers

Rapid Eye Movement (REM) sleep is characterized by which of the following brain wave patterns?

Desynchronized high-frequency activity Signup and view all the answers

What distinguishes NREM sleep from REM sleep in terms of muscle activity?

Decreased muscle tone during REM Signup and view all the answers

In which stage of sleep is memory consolidation notably enhanced?

Stage 2 NREM Signup and view all the answers

What occurs during REM sleep that protects the body from the mind's dreams?

Muscle paralysis Signup and view all the answers

Circadian rhythms influence which of the following biological functions?

Eating and drinking behavior Signup and view all the answers

Which physiological measure is responsible for recording eye movements during sleep research?

Electrooculography (EOG) Signup and view all the answers

How long is the typical NREM to REM sleep cycle in humans?

90 minutes Signup and view all the answers

What kind of sleep is characterized by changes in the brain and body indicated during polysomnography?

REM sleep Signup and view all the answers

What is primarily measured by Polysomnography (PSG) during a sleep study?

Brain waves, eye movements, and muscle tone Signup and view all the answers

What happens to melatonin secretion when light exposure ceases?

It increases Signup and view all the answers

Study Notes

Sleep Measurement

Sleep can be measured through phenomenology, behavior, and physiology.
Phenomenology is based on self-reported experiences, including loss of external awareness, disconnected thoughts, and disorientation.
Behavioral measures include horizontal position, low muscle tone, circadian rhythm, and non-responsiveness.
Physiology is considered the gold standard, involving changes in brain and body activity.
Polysomnography (PSG) is used to measure sleep physiology.

Polysomnography

PSG tracks brainwaves using electroencephalography (EEG), eye movements using electrooculography (EOG), and muscle activity using electromyography (EMG).
EEG measures brain activity, characterized by different wave frequencies and amplitudes.
EOG records changes in voltage near the eye, indicating eye movements.
EMG records muscle activity, often measured under the chin and face.
Participants may require a first night of adaptation to the PSG setup.

Sleep Stages

Sleep is divided into two main categories: NREM and REM.
NREM consists of Stages 1, 2, 3, and 4.
Stage 3 and 4 are often combined and referred to as SWS (slow-wave sleep).
REM is associated with PGO waves and dreaming.
During REM, REM paralysis occurs, inhibiting nerve connections to skeletal muscles to prevent physical actions during dreams.

Sleep Cycle

The NREM-REM sleep cycle lasts approximately 90 minutes.
Deep NREM sleep predominates earlier in the night, while REM sleep increases later.
The hypnogram is a diagram illustrating the stages and duration of sleep.

Sleep Stage Characteristics

Awake is characterized by open eyes with blinks, high-frequency and low-amplitude brain waves, and strong muscle tone.
Stage 1 NREM involves slowing eye movements and slower, larger, synchronized brain waves.
Stage 2 NREM is marked by stopped eye movements and the presence of K-complexes and sleep spindles.
SWS (Stage 3 & 4) exhibits very slow frequency and high amplitude brain waves, with minimal muscle tone and no eye movements.
REM sleep involves closed eyes with rapid horizontal movements, high-frequency and low-amplitude brain waves, and atonia (muscle paralysis).

Circadian Rhythms

Circadian rhythms are endogenous biological cycles that occur in approximately 24-hour cycles.
They regulate sleep/wake cycles, eating, drinking, body temperature, and hormone release.
Zeitgebers are external stimuli that synchronize circadian rhythms.
Light is the most influential zeitgeber, but food, exercise, and activity also have an impact.
The suprachiasmatic nucleus (SCN) acts as the master clock, regulating biological rhythms.
Melatonin is a hormone released from the pineal gland, impacting the SCN and influencing sleep timing.

Circadian Disruptions

Jet lag occurs after crossing time zones, leading to sleepiness during the day and sleeplessness at night.
Circadian disruption can result in cognitive deficits, such as slower reaction times and decreased accuracy.
Sleep deprivation is a potential carcinogen.

Importance of Circadian Rhythms

Circadian rhythms are crucial for optimizing bodily functions.
Synchronization with the 24-hour light/dark cycle allows for efficient energy utilization.
The SCN regulates the timing of hormone release, including melatonin.

Two Process Model of Sleep-Wake Regulation

The two process model describes the interplay of circadian and homeostatic factors that govern sleep.
Process S represents sleep debt and increases during wakefulness, declining during sleep.
Process C represents circadian processes that regulate alertness and arousal.
Process S favors NREM sleep, while Process C favors REM sleep.

Sleep Deprivation

Sleep deprivation significantly increases sleep pressure, leading to daytime sleepiness and increased NREM sleep duration.

Phylogeny of Sleep

Sleep is evident in all animals, but REM sleep is present only in birds and mammals.
REM sleep evolved independently in birds and mammals, indicating its importance for thermoregulation and metabolic regulation.

Insects

Insects exhibit circadian timing, low muscle tone, horizontal position, and non-responsiveness during sleep.

Birds

Birds have shorter sleep cycles compared to mammals.
They exhibit unihemispheric sleep, allowing one brain hemisphere to sleep while the other stays awake.
Birds' REM sleep involves brief bursts of rapid eye movements.

Reptiles, Amphibians, and Fish

These species show evidence of NREM-like sleep but lack distinct REM sleep phases.
REM activity in reptiles remains a subject of debate.

Sleep in Humans

Human sleep patterns have evolved with societal changes.
Hunter-gatherer tribes often utilize short afternoon naps to enhance alertness.
Biphasic sleep involves a period of sleep at night and a short nap during the day.

Neurochemistry of Sleep-Wake Cycle

Acetylcholine (Ach), noradrenaline (NA), and serotonin (5-HT) are key neurotransmitters for regulating sleep.
These substances are released from the brainstem, the "activating center."

Brain Activation During Sleep Stages

Awake is characterized by high brainstem activity, activating the thalamus and cortex for sensory processing.
NREM involves reduced brainstem activity, deactivating the thalamus and leading to limited brain processing.
REM brings about partial brainstem activation, primarily driven by acetylcholine.
The thalamus becomes activated, leading to dream-like experiences in the cortex.
The prefrontal cortex is deactivated, allowing for illogical and emotional content in dreams.

Functional Anatomy of Sleep

Brain activity during sleep stages can be measured using PET and fMRI.
REM sleep involves increased activity in the cingulate cortex (emotional regulation), motor cortex (movement initiation), hippocampus (memory), and occipital cortex (visual processing).
The lateral prefrontal cortex, responsible for logical reasoning, is deactivated during REM sleep.

Chronotype

Chronotype refers to individual differences in sleep timing preferences.
Morningness-Eveningness Questionnaire (MEQ) is a tool used to assess chronotype.
Chronotype can vary with age and environmental factors.
Sentinel Hypothesis proposes an evolutionary explanation for chronotype variation, suggesting that it may provide a continuous watch against predators.

Naps

Naps have been found to enhance memory in infants.
Nap-induced memory improvement can persist for up to 24 hours.
Naps can improve performance on cognitive tasks compared to sleep deprivation.

Sleep Deprivation and Memory

Sleep deprivation negatively impacts memory performance, particularly for complex information.
NREM sleep is particularly important for memory consolidation.

Summary

Sleep is a complex process regulated by circadian and homeostatic processes.
These processes work together to determine sleep stages, duration, and timing.
Understanding the neurochemistry and neurophysiology of sleep is crucial for optimizing sleep quality and improving overall health.

Infant Napping and Learning

Napping after learning significantly enhances memory for infants
Infants who napped remembered more than 24 hours later compared to those who did not nap
The nap group experienced a sleep episode shortly after learning, contributing to better memory retention
The memory task involved observing a puppet perform actions and recalling those actions later.

Sleep and Memory in Preschool Children

Preschoolers who napped performed better on a spatial memory task compared to those who stayed awake
This performance advantage persisted even after 24 hours, indicating that a night of sleep did not negate the benefits of napping
NREM sleep spindle density during naps was positively correlated with improved memory recall, suggesting a role in memory consolidation

Naps and Learning in Middle School Students

A study investigated whether napping enhances learning in middle school students.
Students learned about a new topic and were then assigned to either a nap condition or a regular class.
Those who napped showed improved memory performance on the topic tested 2 and 5 days after the lecture.
Students who did not nap had their memory of the topic decline over time.

Ontogeny of Sleep

Sleep patterns change significantly across the lifespan.
Newborn infants exhibit highly polyphasic sleep - they sleep multiple times throughout the day.
Children gradually transition to monophasic sleep patterns, sleeping once overnight.
The ratio of wake, NREM, and REM sleep also changes over time.
Older adults have shorter sleep durations and less slow-wave sleep compared to younger individuals.

Two-Process Model of Sleep-Wake Regulation

The Two Process model describes the interplay of two factors regulating sleep: Process C (circadian drive) and Process S (sleep pressure).
Process C is a 24-hour cycle influencing our drive to be awake.
Process S accumulates as we are awake, leading to an increasing urge to sleep.
Adenosine is a neurotransmitter that builds up during wakefulness, contributing to Process S.

Creativity and Sleep

Societal anecdotes suggest a link between sleep and creative insights.
Scientific studies demonstrated that REM sleep can improve problem-solving abilities.
Numeric number reduction task found improvements in participants who had slept compared to those who stayed awake.
REM or dream sleep seems to enhance this kind of creative problem-solving.

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Description

This quiz explores the various methods of measuring sleep, focusing on phenomenology, behavioral indicators, and physiological metrics, particularly polysomnography (PSG). Learn about the technologies used in PSG, including EEG, EOG, and EMG, and their importance in accurately assessing sleep patterns.