28 Questions
What are the two processes involved in the Two Process Model of sleep regulation?
Circadian rhythm and homeostatic sleep drive
According to the Two Process Model, what drives the circadian rhythm?
Biological clock
What is the homeostatic sleep drive driven by, according to the Two Process Model?
Amount of time awake
What is the definition of sleep according to the lecture?
Reversible behavioral state of perceptual disengagement from, and unresponsiveness to the environment
What is the active defense of a set point known as?
Homeostasis
What determines sleep propensity and the duration of sleep in the Two Process Model?
2 processes combined
What does the homeostatic sleep drive lead to, as time awake increases?
Progressive tiredness
What are the separate and independent mechanisms that regulate sleep and wakefulness, according to the Two Process Model?
Circadian and homeostatic regulation
What drives periods of sleepiness at roughly the same times each day, according to the Two Process Model?
Circadian rhythm
What is the main function of sleep in relation to the cortex?
Disconnecting the cortex from sensory input
What is the role of thalamic cells in driving rhythms in the cerebral cortex?
Generating rhythmic, self-sustaining discharge patterns
What is the synaptic homeostasis theory of consolidation?
Information encoding during wakefulness leads to an increase in synaptic strength, which is downscaled during sleep
What drives the generation of large EEG signals by synchronous activity?
Synchronous activity of thousands of neurons
What is the role of thalamus in driving rhythms in the cerebral cortex?
Rhythms in thalamus drive rhythms in cerebral cortex
What generates bursts of synchronous neural activity in the awake brain?
Cortical and subcortical components
What is the effect of slow oscillations during slow-wave sleep (SWS) on synaptic strength?
Downscaling synaptic strength
What allows the signal large enough to be seen at the scalp electrode?
Thousands of neurons contributing synchronous activity
What is the main purpose of gamma rhythms in the awake brain?
Binding several components into a common construction
What serves as the brain's way of disconnecting the cortex from sensory input?
Sleep
Which neurotransmitter is involved in the activity of state-regulatory nuclei governing wake, non-REM, and REM sleep?
Serotonin
What is the approximate duration of the human sleep cycle?
90-110 minutes
Which sleep stage is characterized by rapid eye movements and lack of muscle tone?
REM sleep
What regulates the sleep-wake cycle involving nonREM and REM sleep alternation?
Homeostatic, circadian, and ultradian processes
Which diagnostic method involves clinical analysis using subjective measures like the Pittsburgh sleep quality index?
Polysomnography
Which neurotransmitter is part of the wake-on, REM-on arousal systems?
Dopamine
What activates the arousal regions in the sleep-wake cycle?
Orexin
Which sleep-promoting agent is involved in the control of sleep through circadian mechanisms?
Adenosine
What is involved in the objective measures of the sleep-wake cycle and characterizes amplitude, frequency, and patterns often superimposed?
EEG
Study Notes
Understanding the Sleep-Wake Cycle
- Homeostasis maintains steady states in the organism, with sleep drive proportional to prior wakefulness and expressed as EEG delta power during nonREM sleep.
- Three processes regulate the sleep-wake cycle: homeostatic, circadian, and ultradian, involving nonREM and REM sleep alternation.
- Sleep stages include wake, REM sleep characterized by rapid eye movements and lack of muscle tone, and NREM sleep with sustained muscle tone and no eye movements.
- The human sleep cycle lasts approximately 90-110 minutes and is repeated 3 to 6 times per night, consisting of non-REM and REM sleep stages.
- Constantin Von Economo discovered Encephalitis lethargica and its three types: Somnolentophthalmoplegic, Hyperkinetic, and Amyostatic-akinetic (parkinsonism).
- The wake-promoting mechanisms involve the Reticular Activating System, which maintains the conscious, alert state, and is activated by sensory information relayed to the cerebrum.
- Orexin activates arousal regions, while the sleep-promoting mechanisms involve non-REM and REM sleep mechanisms, as well as the circadian control of sleep.
- Amines, acetylcholine, orexin/hypocretin, and GABA are involved in the activity of state-regulatory nuclei governing wake, non-REM, and REM sleep.
- Wake-on, REM-off arousal systems include norepinephrine, serotonin, and histamine, while wake-on, REM-on arousal systems include acetylcholine, dopamine, and glutamate.
- Other sleep-promoting agents include adenosine, proinflammatory cytokines, prostaglandin D2, and growth hormone releasing hormone.
- Sleep diagnostics involve clinical analysis using subjective measures like the Pittsburgh sleep quality index and objective measures such as polysomnography, wrist actigraphy, and EEG, EOG, and EMG.
- Objective measures of the sleep-wake cycle include sleep staging variables like EEG, EOG, and EMG, which characterize amplitude, frequency, and patterns often superimposed, with origins driven by specific neuronal activities.
Test your knowledge of the sleep-wake cycle with this quiz. Explore the processes regulating sleep, the stages of the sleep cycle, and the mechanisms controlling wakefulness and sleep. Learn about diagnostic measures and the factors influencing the sleep-wake cycle.
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