159 Questions
What type of waves are characteristic of alert waking activity and are characterized by sleep spindles on an EEG?
Beta waves
Which type of waves are associated with sleep onset and light sleep (N1) on an EEG?
Theta waves
What is the key characteristic of N2 sleep on an EEG?
Presence of K-complexes
Which theory argues that sleep keeps us safe from predators?
Enhance survival/adaptation (inactivity theory)
Which theory suggests that sleep is designed to restore the body of things that build up during the day?
Restoration theory
Which theory struggles to explain why humans need sleep, as humans have the capacity for relaxed wakefulness?
Energy conservation theory
What is the typical duration of sleep needed by humans?
8 hours
What is the characteristic of beta waves on an EEG?
High frequency and low amplitude
When do sleep spindles occur?
N2 sleep
What helps to stage REM sleep by looking at body movement on an EEG?
Electromyogram (EMG)
What are common issues that result from inadequate sleep?
Impaired cognition
What does sleep look like over the night?
More N3 sleep at start of night and more REM sleep towards end of night
What are the different measures of a polysomnography?
Provides sleep onset latency, total sleep time, sleep efficiency, awakenings, WASO, sleep architecture
What are some subjective ways of measuring sleep?
Sleep diary
What are the primary functions of N3 - deep sleep?
Useful for memory & cognition, physically restorative, synaptic plasticity, brain 'cleaning'
What is the typical duration of one sleep cycle?
60-90 minutes
What is the role of REM sleep?
Memory consolidation, emotional processing
What did early work on wake prompting systems find?
Mid brain (reticular formation) + parts of hypothalamus are involved in sleep + wake
What is the thalamocortical loop?
An ascending activating system maintains an activated cortex -> runs from reticular formation to thalamus to cortex; arouses/awakens the brain' cortex projects back to thalamus forming thalamocortical loop
What is the ascending (reticular) activation system?
It involves two main branches: 1. cholinergic inputs (PPT and LDT) and 2. monoaminergic inputs (norepinephrine, serotonin, histamine, dopamine)
What is the orexinergic system?
The orexin/hypocretin pathway plays an essential role in stabilisation of wakefulness - i.e., these fire exclusively during wake
What causes narcolepsy?
Low waking levels of orexin i.e., caused by a reduction of orexin neurons
What else does orexin control?
Appetite and energy balance
What part of the brain is associated with slow wave sleep?
Temporal lobe
Which neurotransmitter is NOT part of the ascending (reticular) activation system?
GABA
What is the role of the thalamus in the thalamocortical loop?
Receiving input from the cortex and projecting back to the cortex
What is the primary function of the midbrain reticular formation?
Controlling wakefulness and arousal
What is the main function of the ventro-lateral preoptic area (VLPO) in the brain?
To promote inhibitory neurotransmitters during sleep
What is the synaptic homeostasis hypothesis?
Synaptic connections are strengthened during wake and downscaled during sleep
Who first described the ascending reticular activating system?
Moruzzi & Magoun
Where do cholinergic neurons originate from in the brain?
The laterodorsal tegmental (LDT) and pedunculopontine nuclei (PPT)
Where do monoaminergic neurons project to in the brain?
The lateral hypothalamus (LH)
Where do monoaminergic neurons come from in the brain?
Norepinephrine - the locus coeruleus
What is the primary role of the median preoptic nucleus (MnPO) in the brain?
To be highest during sleep onset and dissipate across the night
What are the main functions of the parafacial zone (PFZ) in the brain?
To send upward sleep signals via GABA and switch off areas related to alertness
What is the known function of orexin in the brain?
Stimulates wake, feeding, and reward
What is the meaning of Zeitgeber in the context of circadian rhythm?
It represents the 'outer' day, usually referring to the light cycle
What is the difference between phase delay and phase advance in relation to circadian rhythm?
Light pulse at the beginning of night causes phase delay, while closer to morning causes phase advance
What is the significance of Circadian Time (CT) in the context of circadian rhythm?
It refers to the 'inner' day of an organism, usually activity onset
What are some non-photic causes of phase shifting in circadian rhythm?
Running (on a wheel)
Which gender has a longer intrinsic period in relation to circadian rhythm?
Men have a longer intrinsic period than women
What does the term 'phase angle' refer to in the context of circadian rhythm?
It signifies the difference between intrinsic time and external time
What is the effect of being on a light cycle on the internal clock in circadian rhythm?
Being on a light cycle will pull the internal clock towards its time
What is the 'free running' period of the circadian clock?
Slightly different from the external cycle being measured
What does phase shift refer to in the context of circadian rhythms?
A rapid change in an oscillation from one phase to another
What is the role of zeitgebers in regulating circadian rhythms?
They are external cues that entrain the internal clock
What is the significance of phase angle in circadian biology?
It represents the difference in time between reference points on two oscillations
What is the role of tau in the context of circadian rhythms?
It refers to the length of the endogenous rhythm
Where does melanopsin sit in the eye?
Ganglion cell layer
What are eclosion rhythms related to?
Emerging from the larva (in insects)
What is the core clock in mammals?
Suprachiasmatic nucleus (SCN)
How do we know the SCN is the clock in mammals?
Ablation - removing the clock eliminates rhythms
What is the function of melanopsin in the circadian system?
Provides light input information
What happens when a SCN is transplanted into an arrhythmic animal?
Brings back rhythms
At what age do toddlers typically experience a drop in sleep duration compared to infancy?
3 years
What sleep architecture starts to resemble adults at around 4/5 years of age?
Sleep spindles
What is associated with reduced slow wave sleep in older age?
Prefrontal atrophy
At what age does diurnal preference start to develop?
6 years
What characterizes quiet sleep in foetal sleep?
Precursor to NREM sleep
What is the precursor to REM sleep in foetal sleep?
Active sleep
At what age do newborns start to experience day/night entrainment?
16 weeks
At what age do sleep spindles and K-complexes typically develop in newborns?
6 months
What is the expected sleep duration for newborns?
16 hours
At what age do toddlers typically drop their daytime nap?
3 years
What is the primary sleep issue commonly experienced by children between 4-10 years of age?
Difficulty falling asleep
How is delayed phase sleep disorder diagnosed?
By assessing the individual's subjective account
What is non-24 hour sleep wake disorder characterized by?
Peak melatonin falling at random points in the day
What is acrophase in the context of circadian rhythms?
The peak time for melatonin
How is DLMO (Dim light melatonin onset) used?
To measure entrainment to a 24-hour light/dark cycle
What is the primary characteristic of shift work disorder?
Impaired sleep and impaired wake
What is the significance of measuring melatonin?
To determine the suppression of melatonin by light
What is the typical duration of sleep needed by humans?
7-9 hours
What percentage of people in Australia have sleep complaints?
20-30%
What is a protective factor for sleep issues before bed?
Time with family
What results in increases in sleep latency?
Pre-sleep arousal (e.g., social media)
Who is a particularly vulnerable population to sleep disturbances?
Adolescents
What sleep efficiency percentage is considered good?
85%
Which population has highly variable sleep?
Adolescents
How common is insomnia?
1 in 3 people
What are the components considered in CBT-I?
Stimulus control
What is a risk factor for sleep issues before bed?
Playing video games
What is a common protective factor for sleep issues before bed?
Spending time with family
Which factor is associated with an increase in mortality, especially in terms of cardiometabolic activity?
Disrupting clock with light
What hormonal signal is lower when individuals get less sleep, impacting their ability to feel satiated?
Leptin
What is the primary impact of sleep restriction on glucose tolerance?
Impaired ability to clear glucose from the system
What determines an individual's ability to sleep according to circadian time?
Circadian rhythms
What is the primary association between sleep duration and BMI?
Less sleep leads to higher BMI
What is the impact of light at night on glucose tolerance?
Reduces glucose tolerance
What is the primary function of the sleep/wake homeostat?
Building of sleepiness as one stays awake
What happens when an individual goes to bed a few hours earlier or later than their circadian clock dictates?
They experience much more wakefulness during sleep
What is a potential consequence of circadian misalignment?
Increased risk of obesity
What effect does light exposure have on melatonin and cancer risk?
Light decreases melatonin, increasing cancer risk
What is the impact of shift work on cancer risk, according to the text?
Shift work is associated with increased cancer risk
What is the relationship between circadian rhythm disturbance and cardiovascular disease?
Circadian rhythm disturbance is associated with increased cardiovascular disease
How does light sensitivity differ in bipolar disorder and depression?
Light sensitivity is increased in bipolar disorder but decreased in depression
What is the impact of SSRIs on light sensitivity in individuals with depression?
SSRIs increase light sensitivity in individuals with depression
When are heart attacks most common, according to the text?
Most common in the morning
What is the impact of circadian phase on seasonal affective disorder (SAD) severity?
Moving off an ideal circadian phase increases SAD severity
What is the impact of delayed melatonin secretion on Major Depressive Disorder (MDD) symptoms?
Delayed melatonin secretion correlates with increased MDD symptoms
What is the term for the sleep pattern of having one sleep period per day?
Monophasic
What distinguishes human sleep from that of other mammals?
Shorter duration
What is the evolutionary advantage of sentinel behavior?
Protecting the tribe during sleep
What does the evidence against segmented sleep suggest?
Segmented sleep is a modern phenomenon
What is the term for animals that are active primarily during the night?
Nocturnal
What is the term for animals that are active primarily during the day?
Diurnal
What is the term for animals that are active primarily during twilight?
Crepuscular
What type of sleep pattern is not suited to human adults according to the text?
Polyphasic sleep
What type of light exposure has a larger impact on the circadian system according to the text?
White LEDs
What has enabled humans to reshape sleep patterns at will according to the text?
Electricity
What does spending less time outdoors in sunshine and brighter light at night lead to according to the text?
Worse sleep and phase delay
What is the primary impact of white LEDs on the circadian system according to the text?
Larger impact on melanopsin
What was used by prehistoric humans to see at night, which did not disrupt sleep as much according to the text?
Fire
What type of sleep pattern do humans almost always favor in lab settings according to the text?
Monophasic sleep
What is not adapted to the reshaped sleep patterns enabled by electricity according to the text?
Our physiology
What is a characteristic of rapid entry to REM sleep according to the text?
Sign of REM sleep deprivation
What is sleep insufficiency defined as?
When sleep is insufficient to support adequate alertness, performance, and health
What cognitive domains does sleep loss affect?
Attention, Executive function, and Emotional regulation
What is the definition of alertness?
Non-specific brain activation in relation to sleep and wake
What are some determining factors of alertness?
Chronic sleep restriction, Time of day (phase), Sleep inertia, Presence of sleep disorder
What is a common subjective measure of alertness?
Karolinska Sleepiness Scales
What are objective measures of alertness?
Pupil size, EEG, Self-reported questionnaires
What percentage of Australians report suffering from insufficient sleep?
40%
What is the most common subjective measure of alertness?
Karolinska Sleepiness Scales
What is the primary impact of sleep insufficiency?
Decreased productivity
What are potential work-related issues resulting from sleep insufficiency?
Stroke, Workplace injuries, Depression
What is the impact of chronic sleep restriction on alertness?
Alertness degrades cumulatively with each day that sleep is inadequate
What is the impact of time of day on alertness?
Alertness is worse during the night
What is measured in the Multiple Sleep Latency Test (MSLT)?
Time taken to fall asleep during scheduled naps
What is the main outcome measured in Ocular Derived Alertness Outcomes?
Blink rate
What does EEG derived alertness outcomes measure?
Number of microsleeps
What is attention control networks of the brain affected by sleep insufficiency?
Dorsal - fronto-parietal network reduced control
How does sleep deprivation impact planning?
It impairs planning time
What is the impact of sleep deprivation on decision making?
It is compromised
What is the effect of sleep insufficiency on cognitive flexibility?
It is impaired
What is the primary measure in Psychomotor Vigilance Task (PVT)?
Reaction time to visual stimuli
What part of the brain do the executive functions rely on?
Prefrontal cortex
What is the primary outcome of sleep deprived performance?
Unstable performance
What is the impact of sleep deprivation on amygdala activation?
60% increase in activation
What role does age play in vulnerability to sleep loss in the context of driving performance?
Young drivers are more affected
What are the cons of using averages to measure sleep regularity?
They overlook regularity and variability
What are the three traditional measures of sleep regularity?
Standard deviation, social jetlag, and interdaily stability
What are the pros and cons of using standard deviation to measure sleep regularity?
Pro: Measures intraindividual variability; Con: Does not consider the ordering of days
What is the primary disadvantage of using averages to measure sleep regularity?
They do not capture regularity and variability
What is the purpose of using interdaily stability to measure sleep regularity?
To compare the pattern of activity on each day to the average across days
What does social jetlag measure in the context of sleep regularity?
Difference in average midsleep timing between work/school days and days off
What is the drawback of using standard deviation to measure sleep regularity?
It overlooks the ordering of days
What is the limitation of using social jetlag to measure sleep regularity?
It does not account for intraindividual variability
What is the advantage of using interdaily stability to measure sleep regularity?
It compares the pattern of activity on each day to the average across days
What is the primary limitation of using averages to measure sleep regularity?
They overlook regularity and variability
What does interdaily stability score of 1 indicate?
Super regular pattern of activity
What is the main drawback of using social jetlag to measure sleep regularity?
It does not account for intraindividual variability
What is the primary function of melanopsin in the eye?
Regulating circadian rhythm
What is the impact of light exposure on the human habenula?
Inhibition by light leads to increased optimism
What is the relationship between light exposure and amygdala activation?
Light suppresses amygdala activation
What impact does SSRIs (Selective Serotonin Reuptake Inhibitors) have on light sensitivity?
SSRIs greatly increase light sensitivity
What is the recommended approach to enhance the effectiveness of SSRIs?
Combining light therapy with SSRI treatment
What is the impact of evening light exposure on humans?
Humans are 3-4x more sensitive to evening light than previously thought
What is the impact of blue light on slow wave sleep?
Blue light suppresses slow wave sleep in the frontal brain regions
What is the potential impact of healthy light behaviors on socioeconomic status?
Healthy light behaviors may relate to socioeconomic status
Test your knowledge on the impact of inadequate sleep and the different stages of sleep with this quiz. Explore common issues resulting from lack of sleep such as impaired cognition, weight gain, and depression, and learn about the various stages of sleep including light sleep (N1), moderate depth sleep (N2), and deep sleep (N3).
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