Sleep Psychology Chapter 5

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Questions and Answers

What is the typical duration of REM sleep periods at the beginning of the night?

10-20 minutes (correct)

20-30 minutes

30-45 minutes

5-10 minutes

Which of the following is an example of an ultradian rhythm?

NREM/REM cycle (correct)

Body temperature

Menstrual cycle

Appetite

What characterizes REM sleep based on neurophysiological measurements?

High-amplitude, low-frequency EEG pattern

Increased muscle tone

Inconsistent muscle activity

Greater eye movements and loss of muscle tone (correct)

What is the primary role of an electrooculogram (EOG) in sleep studies?

Measuring eye movements during REM sleep Signup and view all the answers

What percentage of total sleep time is typically REM sleep in adults?

20-25% Signup and view all the answers

Which brain wave pattern is predominantly observed during light sleep (Stage 1)?

Theta waves Signup and view all the answers

What is the primary EEG pattern noticed during REM sleep?

Mixed frequencies Signup and view all the answers

At what frequency range do delta waves occur during sleep?

0.5-4 Hz Signup and view all the answers

Which of the following stages of sleep is primarily associated with the presence of sleep spindles?

Stage 2 Signup and view all the answers

What happens to REM sleep proportion as individuals age, particularly in neonates versus the elderly?

It decreases from 50% to lower proportions Signup and view all the answers

Which type of brain wave activity is prevalent when a person is awake with eyes open and alert?

Beta waves Signup and view all the answers

What is the characteristic feature of Stage 4 sleep?

Predominantly delta waves Signup and view all the answers

Which of the following is true regarding the characteristics of alpha waves?

They are present when eyes are closed and inattentive. Signup and view all the answers

What characterizes a vegetative state?

Awake with sleep-wake cycles but no signs of awareness Signup and view all the answers

Which brain activity measurement is typically very low or non-specific in acute coma?

EEG showing flat or isoelectric patterns Signup and view all the answers

What is the definition of brain death?

Irreversible loss of all cerebral and brainstem activities Signup and view all the answers

What features are associated with brain death?

Loss of pain responses and cranial nerve reflexes Signup and view all the answers

Which process assists in transitioning memories from the hippocampus to more permanent areas in the cortex during sleep?

Memory consolidation Signup and view all the answers

Which mechanism is responsible for a vegetative state?

Damage to the cerebral cortex with retained brainstem functions Signup and view all the answers

What is one of the critical benefits of sleep related to neurotoxic waste removal?

Glymphatic clearance Signup and view all the answers

In the context of neurological responsiveness during acute coma, what is behavioral responsivity?

Any observable reactions in response to external stimuli Signup and view all the answers

What typically happens to cerebral metabolism in a patient diagnosed with brain death?

It shows no glucose metabolism due to cessation of activity Signup and view all the answers

What hormone is primarily secreted during the 'healing and repair' period of sleep, particularly between 10 pm and 2 am?

Growth hormone Signup and view all the answers

Which of the following statements is false regarding acute coma?

Patients may exhibit purposeful behavioral responses Signup and view all the answers

Which of the following is NOT a consequence of sleep deprivation?

Enhanced memory consolidation Signup and view all the answers

What role does sleep have in regulating insulin and carbohydrate metabolism?

Enhancing metabolism Signup and view all the answers

Which physiological benefit of sleep is related to immune system functionality?

Optimized cytokine production Signup and view all the answers

One of the impacts of sleep deprivation includes alterations in neurotransmitter levels. Which area of the brain is particularly affected?

Amygdala Signup and view all the answers

Which process is negatively affected by sleep deprivation, impacting learning and decision-making?

Synaptic pruning Signup and view all the answers

What role do intrinsically photosensitive retinal ganglion cells (ipRGCs) play in the circadian rhythm?

They send signals to the suprachiasmatic nucleus in response to light. Signup and view all the answers

How does the SCN influence melatonin production?

By signaling the pineal gland to produce melatonin as light decreases. Signup and view all the answers

What happens to melatonin levels in the morning?

They decrease to promote wakefulness. Signup and view all the answers

Which neurotransmitter accumulates in the brain to contribute to sleep pressure?

Adenosine Signup and view all the answers

What is the main effect of adenosine accumulation in the brain?

It creates a drive for sleep. Signup and view all the answers

How does the SCN contribute to the synchronization of peripheral clocks in the body?

By regulating circadian rhythms across different tissues. Signup and view all the answers

What is the relationship between light exposure and melatonin release?

Decreased light exposure triggers melatonin release. Signup and view all the answers

Which physiological activities are influenced by the SCN related to the sleep-wake cycle?

Body temperature and metabolism. Signup and view all the answers

Which type of sleep apnea occurs when throat muscles intermittently relax and block the airway during sleep?

Obstructive Sleep Apnea Signup and view all the answers

What neurotransmitter is involved in the regulation of sleep-wake cycles, particularly in narcolepsy?

Orexin Signup and view all the answers

Which diagnostic tool is used to measure orexin levels in the diagnosis of narcolepsy?

Cerebrospinal Fluid Analysis Signup and view all the answers

Cataplexy, characterized by sudden loss of voluntary muscle control, is primarily associated with which type of narcolepsy?

Type 1 Narcolepsy Signup and view all the answers

What is a common risk factor associated with obstructive sleep apnea?

Neck size Signup and view all the answers

Which symptom is characteristic of narcolepsy?

Excessive daytime sleepiness Signup and view all the answers

The phenomenon of sudden sleep paralysis that can occur in narcolepsy is mainly attributed to deficiencies in what?

Orexin levels Signup and view all the answers

Which type of parasomnia involves unwanted events like sleepwalking and night terrors during NREM sleep?

NREM-related parasomnias Signup and view all the answers

What change occurs to the duration of REM sleep as sleep cycles progress throughout the night?

It increases, reaching up to 30-45 minutes. Signup and view all the answers

Which of the following physiological indicators shows a notable decrease during REM sleep?

Muscle activity as measured by EMG Signup and view all the answers

What is the primary use of an electroencephalogram (EEG) in clinical settings related to sleep disorders?

To diagnose and classify sleep disorders like sleep apnea. Signup and view all the answers

Which statement correctly identifies characteristics of the NREM/REM sleep cycle?

The NREM/REM cycle typically has a duration that varies throughout the night. Signup and view all the answers

What is a defining feature of ultradian rhythms, particularly in the context of sleep cycles?

They exhibit cycles that repeat every few hours. Signup and view all the answers

What is the defining characteristic of a vegetative state?

Awake but showing no signs of conscious awareness Signup and view all the answers

In the context of brain death, what typically happens to neuronal activity?

Irreversible end of all brain activity Signup and view all the answers

What distinguishes behavioral responsivity from neurological responsiveness?

Behavioral responsivity is a reaction to external stimuli Signup and view all the answers

Which feature is indicative of a condition leading to brain death?

Loss of spontaneous respiration Signup and view all the answers

What is primarily retained in a vegetative state despite the damage to the cerebral cortex?

Brainstem functions Signup and view all the answers

How is the presence of cranial nerve reflexes affected in a brain death scenario?

All cranial nerve reflexes are absent Signup and view all the answers

What type of brain activity is typically observed in an acute coma?

Generally non-responsive, low brain activity Signup and view all the answers

What is the consequence of total brain anoxia in relation to brain death?

Irreversible damage leading to neuronal death Signup and view all the answers

What is the key feature that differentiates coma from vegetative state?

Ability to respond to painful stimuli Signup and view all the answers

Which characteristic is NOT associated with consciousness?

Absence of perceptual ability Signup and view all the answers

What distinguishes brain death from coma or vegetative state?

Complete and irreversible loss of all brain function Signup and view all the answers

In the context of sleep stages, which of the following measurements is least likely to be used for characterization?

Functional magnetic resonance imaging (fMRI) Signup and view all the answers

Which statement most accurately describes a feature of unconsciousness?

Temporal lack of responses with potential for recovery Signup and view all the answers

What is a primary function of sleep that is critical for cognitive processes?

Facilitating memory consolidation Signup and view all the answers

Which of the following best describes the nature of a vegetative state?

Preserved autonomic functions with no evidence of awareness Signup and view all the answers

What is commonly observed in patients diagnosed with locked-in syndrome?

Complete paralysis except for eye movements Signup and view all the answers

What physiological benefit of sleep primarily aids in tissue repair and muscle recovery?

Cellular regeneration Signup and view all the answers

Which of the following statements is true about neurogenesis during sleep?

It is supported by the secretion of growth factors. Signup and view all the answers

How does sleep deprivation most significantly affect mood?

By altering neurotransmitter levels and neural activation Signup and view all the answers

What is the role of the glymphatic system during sleep?

It removes neurotoxic waste from the brain. Signup and view all the answers

Which of the following factors does NOT contribute to impaired metabolism due to sleep deprivation?

Decreased cortisol levels Signup and view all the answers

What effect does slow-wave sleep have on growth hormone secretion?

It enhances growth hormone secretion during sleep. Signup and view all the answers

In what way does sleep support immune system functionality?

By optimizing T-cell activity Signup and view all the answers

Which cognitive function is most directly impaired by sleep deprivation?

Attention and decision-making Signup and view all the answers

What is the primary diagnostic tool for identifying obstructive sleep apnea?

Polysomnography Signup and view all the answers

Which of the following is a neurotransmitter associated with the regulation of sleep-wake cycles?

Orexin Signup and view all the answers

Which of the following symptoms is not typically associated with narcolepsy?

Frequent snoring Signup and view all the answers

The type of sleep apnea characterized by the brain not sending proper signals to the muscles that control breathing is known as:

Central sleep apnea Signup and view all the answers

What is the main distinguishing feature of Type 1 narcolepsy?

Presence of cataplexy Signup and view all the answers

In the context of sleep disorders, which of the following is a common risk factor for obstructive sleep apnea?

Alcohol use Signup and view all the answers

What sleep disorder is characterized by unwanted experiences occurring while falling asleep, during sleep, or waking up?

Parasomnia Signup and view all the answers

Which of the following is a potential cause of narcolepsy in patients with Type 1?

Genetic predisposition Signup and view all the answers

What is the primary photopigment found in intrinsically photosensitive retinal ganglion cells (ipRGCs)?

Melanopsin Signup and view all the answers

Which hormone is produced by the pineal gland and regulated by the suprachiasmatic nucleus (SCN)?

Melatonin Signup and view all the answers

What happens to adenosine levels in the brain as a person spends more time awake?

They accumulate gradually. Signup and view all the answers

How does the SCN influence the body’s various physiological processes?

By communicating with peripheral clocks. Signup and view all the answers

In which phase of the day do melatonin levels typically rise?

In the evening as light levels decrease. Signup and view all the answers

What role does homeostatic sleep pressure play in the sleep-wake cycle?

It gradually increases with time spent awake to create a drive for sleep. Signup and view all the answers

Which physiological function is NOT influenced by the suprachiasmatic nucleus?

Muscle contraction Signup and view all the answers

What is the relationship between light exposure and the regulation of melatonin?

Light exposure decreases melatonin production. Signup and view all the answers

Study Notes

Course Information

Class: Year 2 Semester 1
Course: CNS
Code: CNS
Title: Consciousness, Unconsciousness, Sleep & EEG
Lecturer: Dr. Melanie Föcking (RCSI-IE), Dr. Colin Greengrass (RCSI-BH)
Date: 08.11.2023

Learning Objectives

ALO167: Define consciousness and unconsciousness and describe coma, vegetative state and brain death
ALO168: Characterise circadian rhythms, ultradian rhythms and sleep stages
ALO169: List neurophysiological measurements to characterise sleep stages
ALO170: Recall benefits of sleep
ALO171: Describe the regulation of sleep-wakefulness cycle
ALO172: List sleep disorders

Defining Consciousness, Unconsciousness, Coma, Vegetative State, and Brain Death

ALO 167: Defines consciousness and unconsciousness, and describes coma, vegetative state, and brain death.
Images of brain scans depicting healthy control, brain death, and vegetative state are included, showing differences in metabolic activity.

O-PET fMRI

Assesses cerebral metabolism in various states of consciousness (healthy individuals, vegetative state, locked-in syndrome, minimally conscious).
Colour scale indicates glucose metabolism per 100 g of brain tissue per minute.

Consciousness

Definition: A state of self-awareness, perception, ability to respond to stimuli, and ability to act with judgment.
Features: Characterised by an individual's awareness of their surroundings, thoughts, feelings, memories, and internal sensations. Encompasses the ability to perceive, communicate, and exhibit purposeful behaviour.

Unconsciousness

Definition: A temporary or prolonged state where there's a lack of responsiveness to external stimuli and an absence of voluntary actions.
Features: Absence or disruption of consciousness where an individual cannot respond to external stimuli.

Coma

Definition: State of profound unconsciousness with inability to sense or respond to external stimuli and loss of sleep-wake cycle.
Features: Profound unresponsiveness, inability to move spontaneously, no response to painful stimuli, and inability to be awakened.
Mechanism: Often involves injury to both cerebral hemispheres or the reticular activating system in the brainstem.
Causes: Intoxication, acute neurological injuries, metabolic disorders, CNS infection, stroke, hypoxia.
Duration: Generally, few days to few weeks (2-5 weeks).
Some patients progress to a vegetative state or die.
Glasgow Coma Scale (GCS) is used for classification of acute traumatic brain injury based on the level of consciousness;
- Severe (GCS 3-8)
- Moderate (GCS 9-12)
- Mild (GCS 13-15)

Sleep

Sleep is a state of changed consciousness from which a person can be aroused by stimulation.
Alternates with wakefulness in a 24-hour cycle (circadian rhythm).
Physiological state.

Vegetative State

Condition of wakefulness that lacks awareness.
Individuals have sleep-wake cycles but do not show any signs of consciousness or purposeful activity.
Mechanism: Damage to the cerebral cortex, but retention of some brainstem functions.

Brain Death

Definition: An irreversible cessation of all cerebral and brainstem activities.
It is the irreversible end of all brain activity due to the total necrosis of cerebral neurons after the loss of blood flow and oxygenation.
Mechanism: Total brain anoxia leading to neuronal death.
Features: Loss of pain responses, cranial nerve reflexes (like pupillary response, fixed pupils), loss of spontaneous respiration.

Circadian Rhythms, Ultradian Rhythms, and Sleep Stages

ALO168: Characterises circadian rhythms, ultradian rhythms, and sleep stages.
Circadian Rhythm: Biological processes that have an endogenous oscillation of about 24 hours.
- Mechanism: Regulated primarily by the suprachiasmatic nucleus (SCN) of the hypothalamus.
- Features: Roughly 24-hour cycles regulating physiological processes influenced by the natural environment (e.g., light-dark cycles).
Ultradian Rhythm: Biological processes that display an endogenous oscillation several times within 24 hours.
- Mechanism: Includes hormonal feedback loops, NREM/REM sleep cycle, and hunger cycles.
- Features: Occurring several times within a 24-hour period.
Sleep Stages: distinct patterns of brain waves during sleep.
- Includes Non-REM (NREM) and REM sleep stages Non-REM has four stages (1-4), with stage 4 being the deepest, including extremely slow brain waves and difficulty waking the person. REM sleep is characterized by rapid eye movements, muscle paralysis, and vivid dreams.
- EEG waveforms are shown depicting different stages.

Measurements for Sleep Stages

ALO169: neurophysiological measurements to characterise sleep stages.
EEG, EOG, and EMG measure brain waves, eye movements, and muscle activity respectively to characterize sleep stages.

Benefits of Sleep

ALO170: Recall benefits of sleep.
Cognitive Benefits: Includes memory consolidation, glymphatic clearance, and neurogenesis.
Physiological Benefits: Includes cellular regeneration, immune modulation, endocrine homeostasis, muscle recovery, energy rebalance, and glycaemic control.

Regulation of Sleep-Wakefulness Cycle

ALO171: Describes the regulation of sleep-wakefulness cycle.
Reticular activating system (RAS): A network of neurons in the brainstem plays a critical role in regulating arousal and wakefulness. Projects to various brain regions, facilitating transitions between different states of consciousness.
Neurotransmitters: Acetylcholine, noradrenaline, serotonin, and histamine promote wakefulness and alertness. Orexin promotes arousal and sustains wakefulness.
Suprachiasmatic nucleus (SCN): Central regulator of the sleep-wake cycle. Receives input from light-sensitive cells in the retina and controls melatonin production in the pineal gland.

Sleep Disorders

ALO172: Lists sleep disorders.
Insomnia (difficulty falling or staying asleep).
Excessive daytime sleepiness (EDS) .
Sleep apnoea (pauses or shallow breathing during sleep).
Narcolepsy (periods of excessive daytime sleepiness and sudden, irresistible bouts of sleep).
Parasomnias (unwanted events or experiences during sleep, including sleepwalking, sleep terrors, confusional arousals, REM sleep behaviour disorder, recurrent isolated sleep paralysis, nightmare disorder).
Restless legs syndrome.

Studying That Suits You

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Description

Test your knowledge on the various aspects of sleep, focusing on REM sleep, sleep stages, and related neurophysiological measurements. This quiz covers topics such as ultradian rhythms, brain wave patterns, and the functions of different sleep stages. Perfect for students studying psychology and sleep science.