Week 5 - Sleep Flashcards

1
Q

Function of sleep

A
  • Immune system functioning
  • Neurological development
  • Memory processing
  • Many, many other functions
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2
Q

Every living animal with a _____ sleeps

A

CNS

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3
Q

Food chain and how long we sleep

A
  • Those higher on the food chain tend to sleep longer than those lower down (e.g., python sleeps 18 hours versus a giraffe, which sleeps 1.9 hours)
  • Humans tend to fall right in the middle at
    around 8 hours per night
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4
Q

Measuring sleep stages

A

Measured with
electroencephalogram (EEG)

Gold standard: polysomnography (Tracks brain waves, blood oxygen
levels, heart rate, breathing, and
eye and leg movements)

Synchronous delta activity: If the cells are active at about the same time, their electrical messages are synchronized and appear as a large, clear wave in the EEG data

Desynchronous beta wave activity: If neurons are active at
different times, their electrical messages are desynchronized and
appear as small, chaotic waveforms without a clear pattern in the EEG data.

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5
Q

5 stages of sleep

A

Wakefulness
NREM stage 1
NREM stage 2
NREM stage 3
REM

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6
Q

Stages of sleep and their waves

A

Wakefulness - alpha and beta
NREM stage 1 - theta
NREM stage 2 - k complex and sleep spindles
NREM stage 3 - delta
REM - theta and beta

*The Silly Kids Don’t Think Bout (sleep)

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7
Q

Total time in sleep for each NREM Stage

A

NREM stage 1 - 2/5%
NREM stage 2 - 50%
NREM stage 3 - 20%

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8
Q

NREM 1

A
  • Transition between wakefulness and sleep
  • Lightest stage of sleep (may not realize you were sleeping)
  • Theta waves (4/7Hz)
  • 2-5% of total sleep time
  • Hypnic jerks
  • Increased proportion suggests sleep fragmentation
    –> E.g., chronic pain
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9
Q

NREM 2

A

About half the night is spent in N2

Experience:
* Slowed heartrate, breathing, muscle activity, eye movements
* Reduced body temperature

Characterized by:
* Sleep spindles
* K complexes

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10
Q

NREM 3

A
  • Commonly referred to as deep sleep or slow wave sleep (SWS)
  • Low frequency, high amplitude DELTA waves
  • 20% time spent (increases with physical exertion)
  • MOST restorative sleep stage (memory consolidation, waste clearance)
  • Predominates the first half of the night
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11
Q

REM Sleep

A
  • Rapid eye movement sleep
  • Muscle paralysis
  • Dreams
  • Easily awoken from this stage
  • Desynchronized EEG
  • Absence of movement on EMG
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12
Q

Slep Cycles

A

Each cycle lasts
approximately 90 minutes

  • Alternates between REM
    and NREM
  • SWS (NREM stage 3) predominates first
    half of the night
  • REM predominates second
    half
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13
Q

Brain activity in REM and Dreaming

A

Prefrontal cortex: low activity (why dreams have no planning, etc.)

Cerebral blood flow is high in the
extrastriate cortex (visual) but low in the striate (primary) visual cortex and
prefrontal cortex

Brain regions active during a dream are same as in real life

Lucid dreaming: eye movements maybe correlated to visual movements in dreams

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14
Q

Deficiency in REM sleep

A

Called the rebound phenomenon

Made up later

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15
Q

Lucid dreams

A

A state where one is “physiologically asleep while at
the same time aware that they are dreaming, able to intentionally
perform diverse actions, and in some cases remember their waking
life” (Baird, Mota-Rolim, & Dresler, 2019)

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16
Q

Brain Activity in Slow-Wave Sleep

A
  • Involves slow oscillations synchronized across large neuronal regions –> memory consolidation
  • Initiation of cortically-based slow wave oscillations largely based in the prefrontal cortex
  • Prior work suggested global decrease in neural activity during SWS
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17
Q

Sleep deprivation

A

record: 11 days

See issues in daylight savings (increase MI, traffic accidents, sucide, etc.)

Fatal familial insomnia: neurological disorder, damages thalamus, death after 12 months

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18
Q

Is sleep important following physical exertion?

A

probably not!

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19
Q

Is sleep important following cognitive exertion?

A

YES!

SWS permits the brain to rest and recover from its daily cognitive activity

SWS increases after a day or weeks of intense cerebral activity

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20
Q

Neurologically, sleep is important for many processes, including:

A
  • Waste clearance
  • Memory consolidation
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21
Q

Sleep and memory consolidation

A

SWS: there is a reactivation of recently encoded memory representations
* Thought to be important for transferring them
to long-term memory store
* AKA playing through through again

REM sleep: stabilizes transformed memories

(May occur across physiological systems: Immunological memories encoded/stored
during sleep)

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22
Q

Synaptic Homeostasis theory

A

During SWS, synapses are pruned back (increases efficiency of brain)

23
Q

REM and neurological development

A

Highest proportion of REM sleep is during the most active phase of brain development: infancy and childhood

Becasue REM sleep supports memory and learning

24
Q

REM and SWS: Long term memories (nondelcarative vs declarative)

A
  • REM sleep facilitates consolidation of nondeclarative memories
  • Slow-wave sleep facilitates consolidation of declarative memories (The brain rehearses newly learned information during slow-wave sleep)

REM: NONDECLARATIVE

SWS: DECLARATIVE

25
Q

Chemicals at play

A
26
Q

Adenosine (inhibitory)

A

Inhibitory response

Steps:
1) Astrocytes store glycogen for “emergency energy,” break down into glucose to give to neurons
2) By product of that is adenosine,
3) Accumulation of adenosine triggers DELTA sleep
4) throughout day body naturally accumulates adenosine, which helps us feel sleepy at night
5) during the night, body recycles adenosine

Sleep Depriva􀆟on = ↓ Glycogen Stores & ↑ Adenosine = SLEEPINESS

27
Q

Adenosine and Caffine

A

Caffeine blocks adenosine receptors, so you don’t feel sleepy but are still sleepy

28
Q

Adenosine and Caffeine

A

Caffeine blocks adenosine receptors, so you don’t feel sleepy but are still sleepy

29
Q

Histamines

A

produced in hypothalamus, relays to brain

MAKES YOU FEEL AWAKE

Histamines also activate release of ACH

Antihistamines: makes you sleepy

30
Q

Acetylcholine

A

High during wakefulness and REM, low during SWS

Hallmark of REM sleep

1 neuron in the Hippocampus, 2 located in the Pons and Forebrain

Produce cortical desyncrhony and activation

Cortical Desynchrony = low voltage mixed
frequencies

31
Q

Serotonin

A

Serotonin plays a role in activating behavior, stimulation causes locomotion and cortical arousal. IT AROUSES

SO most active during waking, low during REM becasue you have limited movement

32
Q

Norepinephrine

A

BOTH Arousal & Sleeplessness controlled by norepinephrine

This is mediated by the Locus Coeruleus in the PONS.

↑ Locus Coeruleus Firing = ↑ Vigilance/Focus

33
Q

Orexin

A

Secreted by hypothalamus

Stimulates other neurons to promote alertness & energy metabolism in response to stress in the environment.

High during alert or active waking, especially exploratory activity

34
Q

WHere is melatnonin produced

A

Pineal Gland

35
Q

Melatnonin

A

Produced by the Pineal Gland in response to evening/darkness about 2 hours
before normal sleep time

Serotonin is converted into melatonin

Exogenous melatonin = take 1-2mg 30 to 1 hr before bedtime (higher just peed out)

Doesn’t keep you asleep, just puts you to sleep

36
Q

Sleep disorders: Trends in sleep in USA

A
  • 25% less sleep than earlier generations
  • 20% Americans employed in shift work
  • 40% of adults report falling asleep during the day without meaning to at least once a
    month
37
Q

Insomnia

A

effects 30% of adults, mostly women (40 vs 30)

Insomnia disorder has a high comorbidity rate with chronic medical conditions

CBTI most effective

Chronic use of sleep-promoting drugs can cause rebound insomnia

38
Q

Primary and secondary insomnia

A

Primary insomnia = difficulty falling asleep after going to bed or after awakening during the night.

Secondary insomnia = inability to sleep due to another mental or physical condition (e.g., pain, medication)

39
Q

Narcolepsy

A

Orexin-related neurological d/o (missing 85%)

39
Q

Narcolepsy

A

Orexin-related neurological d/o (missing 85%)

Most people have sleep attacks (overwhelming urge to sleep during something boring) -> but people with narcolepsy just fall asleep

40
Q

Narcolepsy: cataplexy

A

sudden muscle weakness/paralysis

  • Triggered by strong emotional reaction or physical exertion
  • Remain fully conscious.
  • Loss of muscle control d/t massive inhibition of motor neurons in spinal cord
41
Q

Narcolepsy: Sleep paralysis

A

inability to move before onset of sleep or waking

hypnagogic Hallucinations (visual)

42
Q

Narcolepsy

A

Treatment = modafinil

43
Q

REM Sleep Behavior D/O

A

Lack of muscle paralysis during REM –> acting out of dreams

Can be comorbid narcolepsy

later in life, neurodegenerative

Clonazepam

44
Q

Sleep Apnea

A

Difficulties sleeping and breathing at the same time ↑CO2 = stimulates
chemoreceptors –> wake up gasping for air & decreased slow wave activity

Untreated causes significant deficits in attention, memory, & exec fxns, and anxiety (wake up anxious because of extra co2)

CPAP and BIPAP

45
Q

Two types of sleep apnea

A

Obstructive Sleep Apnea = d/t narrowing of airway (obesity, enlarged tonsils,
hormonal changes)

Central Sleep Apnea = brain does not signal need to breath.

46
Q

Maladaptive Slow-Wave Sleep Bxs in Children

A

Children typically outgrow

bedwetting, sleepwalking, night terrors

Could be all three or a combination.

47
Q

Night terrors vs nightmares

A

terror = Wake up with no memory of the nightmare

48
Q

Disordered Circadian Rhythms: Alzheimers

A

body temp lowers at off time (9-noon vs. 4-5 a.m), see return of sleep walking

49
Q

Disordered Circadian Rhythms: schizo

A

Melatonin production lags, so starts around 2-3am

50
Q

Disordered Circadian Rhythms: Depression

A

40-65% report sleep px

51
Q

Disordered Circadian Rhythms: suicide

A

Sleep deprivation independent risk factor

52
Q

Sleep D/O’s Post- TBI

A

Up to 80% report sleep problems after injury
–> typically dropped to 50% by half year mark

Poor sleep = poorer recovery trajectory d/t increased risk for mood d/o’s, ongoing cog deficits, and neurodegeneration.

53
Q

Nap lengths

A

10-20: feel alert after, because only in NREM

30 minutes: BAD, feel groggy

60 minutes: groggy, but do learn some

90: Best