Intro to Sleep + Techniques - Forster, Franco Flashcards Preview

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Flashcards in Intro to Sleep + Techniques - Forster, Franco Deck (31):

What is the definition of sleep? How do you differentiate sleep from coma or anesthesia?

Sleep: Unconsciousness from which th person can be aroused by sensory or other stimuli.

Coma / Anesthesia: Person cannot be aroused.


Describe the putative functions of NREM vs. REM sleep.

NREM: "physical upkeep"

  • Growth, tissue repair, waste clearance
  • Immune system enhancement
  • Restoration of cerebral energy stores

REM: "mental upkeep"

  • Information processing
  • Purging of irrelevant information
  • Memory consolidation
  • Facilitates learning & memory


Name the stage of sleep in which the following are noted:

  1. Alpha waves
  2. Theta waves
  3. Delta waves
  4. Sleep Spindles
  5. K complex
  6. Sawtooth waves


  1. Alpha waves: Awake / Drowsy
  2. Theta waves: Stage 1
  3. Delta waves: Stages 3 & 4 (Deep)
  4. Sleep Spindles: Stage 2
  5. K complex: Stage 2
  6. Sawtooth waves: REM


  1. Describe general sleep architecture for a healthy young adult.
  2. How does this differ from infant sleep architecture?
  3. From sleep architecture in the elderly?

  1. Initial progression from Stage 1 → 4. After a while in deep sleep, rise back through earlier stages before arriving at REM. After a short REM period, sink back into deep sleep. As further cycles occur, REM periods become longer and more frequent, and the lowest level of sleep reached becomes shallowed (around Stage 2 instead of deep sleep).
  2. Infants may sleep for less time contiunuously, but have more total sleep during a day, as well as more REM sleep.
  3. The elderly have little deep (Stages 3 & 4) sleep, less REM, and their sleep is more fractionated with more cycles.


Approximately how much of a full night's sleep is spent in each of the following sleep stages?

  1. Stage 1 (N1)
  2. Stage 2 (N2)
  3. Stages 3 & 4 (N3)
  4. REM (R)
    • How much does REM decrease with age?


  1. N1: 2-8%
  2. N2: 45-55%
  3. N3: 13-23%
  4. R: 20-25%
    • Decreases ~1.0% of absolute per decade


Do you dream in NREM or REM sleep?

Both, but typically only REM dreams are recalled.


What phase of sleep is called paradoxical sleep, and why?

REM sleep, because it is similar to wakefulness in terms of EEG readings.


In a popular model of the sleep-wake cycle, two major processes are said to control wakefulness vs. sleepiness. Name and describe these two processes.

  1. Process HHomeostatic process. The longer awake, the greater propensity to sleep.
  2. Process CCircadian oscillatory process that affects the propensity for sleep vs. wakefulness dependent on the time of day.


  1. What part of the brain controls the circadian rhythm?
  2. The circadian rhythm can be trained / reset to match the day length. How is this accomplished?

  1. Suprachiasmatic nucleus (SCN) of the hypothalamus
    • About 10,000 neurons
  2. Environmental photoperiod is matched via photoreceptors in the retina which communicate with the SCN
    • These photoreceptors are seperate from those used in sight


  1. How long is the normal period of the circadian rhythm?
  2. How long is the period of the circadian rhythm if environmental cues are removed (e.g. all natural light, complete retinal blindness)?

  1. 24 hours
  2. 26 hours


Name the patterns of sleep indicated by the blue, pink, and red lines.

Q image thumb

A image thumb

For each of the factors listed below, state whether that factor is wake-promoting or sleep-promoting.

  1. Cytokines (e.g. interleukins)
  2. Adenosine
  3. Serotonin
  4. Epinephrine
  5. Cortisol
  6. Prostaglandin D2
  7. Somatostatin
  8. Histamine
  9. Glutamate

  1. Cytokines: Sleep
  2. Adenosine: Sleep (caffeine blocks adenosine receptors)
  3. Serotonin: Can be either!
  4. Epinephrine: Wake
  5. Cortisol: Wake
  6. Prostaglandin D2: Sleep
  7. Somatostatin: Sleep
  8. Histamine: Wake
  9. Glutamate: Wake


  1. Neurons in the raphe pallidus produce ________.
  2. Neurons in locus coeruleus produce ________.
  3. Neurons in the PPT and LDT produce ________.

  1. Serotonin
  2. Norepinephrine
  3. Acetylcholine


During REM sleep, state whether activity from each of the following brain areas increases or decreases. What is the interaction between these areas?

  1. Locus coeruleus
  2. Raphe pallidus
  3. LDT/PPT
  4. Gigantocellular tegmental field (FTG)

  1. Decreases
  2. Decreases
  3. Increases
  4. Increases

Decreased NE and 5-HT from 1 + 2 release inhibition of 3 + 4, which produce ACh and activate REM.


Compared to wakefullness, REM sleep has (increased / decreased):

  1. Norepinephrine
  2. Serotonin
  3. Acetylcholine

  1. Decreased
  2. Decreased
  3. Increased


  1. What are PGO waves?
  2. Where do they originate?
  3. When do they appear most frequently?

  1. Ponto-geniculo-occipital waves
  2. Pons, LGN, and occiptal cortex
  3. Immediately preceeding REM sleep


Compared to NREM sleep, REM sleep has (increased/decreased):

  1. Mean discharge rate of neurons
  2. Cerebral glucose utilization
  3. Cerebral blood flow

  1. Increased
  2. Increased
  3. Increased


Compare body movements between NREM and REM sleep.


  • Few motor events
  • But there is body repositioning


  • Paralysis via postsynaptic motorneuron inhibition 
    • hyperpolarization
  • Phasic events
    • REM
    • Muscle twitches


During what stages of sleep is periodic breathing noted?

What breathing abnormalities can be seen during REM sleep?

Periodic: Stages 1 & 2 (Regular breathing occurs in Stages 3 & 4)


  • Irregular timing & amplitude of ventilation
  • paradoxical respiration
    • (Rib cage moves inward when abdomen moves outward)


True / False: The decrease in ventilation during sleep is equal to the concurrent decrease in metabolic rate.


The ventilatory decrease is greater than the metabolic decrease, leading to increased PaCO2 and a sleep-induced hypoventilation. The hypoxic & hypercapnic responses are blunted.

(Unique to humans among mammals.)


During sleep, when does metabolic rate begin to accelerate again?

~5:00 AM


Does sympathetic or parasympathetic activity dominate during NREM sleep? During REM sleep?

Parasympathetic predominates during both NREM and REM


What happens to total vascular resistance during sleep?

Slight decrease


How does the sleep/wake cycle affect plasma levels of the following hormones? At what time during sleep do levels peak?

  1. Growth Hormone
  2. PTH
  3. Cortisol


  1. GH: Duration of 1-3 hours, supressed with sleep deprivation
  2. PTH: Increases during sleep
  3. Cortisol: Decreases with sleep onset.


  1. GH: 90min after sleep onset
  2. PTH: 2:00-4:00am
  3. Cortisol: 4:00-8:00am


Describe the changes in thermoregulation during NREM and REM sleep.


  • Lowered temp set point
    • Shivering threshold lower
    • Sweating at normal ambient temp


  • No regulation
    • No shivering response
    • No sweating at high ambient temp
    • Body temp drifts toward ambient temp


Name three types of sleep disorders that polysomnography is useful for diagnosing.

  1. Sleep disorded breathing
    • OSA
    • CSA
  2. Periodic Limb Movement Disorder
  3. Parasomnias


Describe the difference between obstructive, central, and mixed sleep apnea.

Obstructive: Lack of airflow with respiratory effort

Central: Lack of airflow without respiratory effort

Mixed: Some respiratory effort during apnea, some lack of effort


What is a sleep diary useful for?

What are its limitations?

What data are included in sleep diaries?


  • Quantifying sleep
  • Assessing pattern of sleep
  • Assessing factors affecting sleep timing


  • Subjective reporting
  • No measurements of breathing


  • Time: When you go to bed, when you wake up
  • Naps
  • Where you slept
  • When you had:
    • Meals, snacks, caffeine, alcohol, exercise, or medicine


What is actigraphy useful for? What is a major limitation?


  • Wearable motion detector
  • Complements sleep diary
  • Objective quantification of sleep over time, sleep pattern
  • Research & clinical tool for quantifying sleep in large numbers of people

Limitation: Not reliable in insomnia


  1. What is a Multiple Sleep Latency Test (MSLT)?
  2. What does it measure?
  3. What is a normal value? A pathologic value?
  4. What other finding indicates sleep pathology?

  1. 20 minute opportunities to nap every 2 hours for 5 sessions in a row
  2. Sleep Latency: time from lying down until falling asleep, measured in minutes
  3. "Normal" is >10 minutes. Pathologically sleepy is <8min
  4. REM sleep during more than one nap is abnormal


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