Sleep Flashcards
(93 cards)
1
Q
What are the four stages of sleep?
A
1) non-rem stage 1
2) non-rem stage 2
3) non-rem stage 3
4) rem
2
Q
How do the sleep cycles change during the night?
A
- early stages: mostly deep sleep (stage 3/4)
- later stages: mostly REM sleep/stage 1/2 sleep
3
Q
How is sleep measured?
A
- EEG to measure brain activity
- EMG (electromyogram) to measure muscle activity
- EOG (electro-oculogram) to measure eye activity
4
Q
What is measured in the brain activity during sleep?
A
the synchronization (or not) of neurons
5
Q
What are the different types of brain activity?
A
- beta activity
- alpha activity
- theta activity
- delta activity
6
Q
What is beta activity?
A
- typical of aroused states
- desynchronous neural activity
7
Q
What is alpha activity?
A
- awake people in relaxed states
8
Q
When does theta activity appear?
A
- when people are drowsy and in the early stages of sleep
9
Q
When does delta activity appear?
A
- during deepest stages of slow-wave sleep
10
Q
What characterizes delta activity?
A
highly synchronized low frequencies
11
Q
What characterizes theta activity?
A
desynchronized EEG activity
12
Q
What caracterizes REM sleep?
A
- rapid eye movements
- sleep paralysis
- dreaming
- increased cerebral blood flow
- increased oxygen consumption
- desynchronized EEG activity
13
Q
What caracterizes stages 3 and 4 of brain activity?
A
- large amplitude and high synchronicity in brain activity
14
Q
What happens when an animal is sleep deprived for many weeks at a time?
A
- cognitive problems
- loss of control of the metabolic processes: body overheats, the rat looses too much weight and dies
15
Q
What are the main effects of sleep deprivation?
A
- sensation of tiredness
- delayed reaction time
- poor judgment
- increse in stress hormones/mood swings/impulsive behavior
- worst learning and memory
- heightened propensity for: weight gain, migraines, hallucinations, dementia, seizures, death
- tends to exacerbate effects of mental illness
- apparition of microsleep states
16
Q
How do sleep patterns vary within a species?
A
- depending on developmental stages
17
Q
What is particular about the way dolphins sleep?
A
- one side of the brain is in deep sleep, the other side is awake
18
Q
What are the elements that allow us to identify differences in sleep behavior among different species?
A
- amount of sleep needed
- ratio of REM to non-REM
- length of sleep cycles
19
Q
How do we differentiate different sleep cycles?
A
Time between two periods of REM sleep
20
Q
What is generally the biggest difference in sleep behavior between predatory and preyed animals?
A
predatory animals indulge in long and uninterupted periods of sleep. preyed upon animals typically sleep in short intervals.
21
Q
What is the correlation between sleep and body weight?
A
smaller animals sleep more than bigger animals
22
Q
how are the basal metabolic rate and mass correlated?
A
positively correlated
23
Q
What is the basal metabolic rate?
A
How many calories an animal burns to stay alive
24
Q
How are the metabolic rate per cell and mass correlated?
A
the more mass increases, the more the metabolic rate per cell decrease
25
How are the heart rate and the size of the animal correlated?
The bigger the animal, the lower the heart rate
26
What does the correlation between metabolic rate per cell and sleep time seem to suggest reguarding sleep?
that sleep may be critical for a restorative process
27
What could explain the correlation between metabolic rate per cell and animal size?
- economies of scale related to heat savings and nutrient/waste distribution networks
- smaller animal=less cells=more work per cell to keep the animal alive
28
What are the main theories about the reasons why animals sleep?
1) to recover from exhaustion (physical or mental)
2) to allow brain processing
3) to allow waste removal
29
What is the general idea of the recovery sleep hypothesis?
- sleep to conserve energy when we are not "hunting", or to recover the energy spent in mental or physical activity
30
What are the problems with the recovery sleep hypothesis?
- sleep is not energy saving
- no clear correlation between exertion and amount of sleep needed
31
What is the brain processing theory of sleep?
- sleep gives the brain an opportunity to reorganize data and archive memories (processing and transfer of information)
- synaptic modificaitons are observed during sleep
32
What appears to support the brain processing theory of sleep?
- correlation between the amount of slow-wave/REM sleep and improvements in declarative and procedural memory
33
What type of learning is associated with slow wave sleep?
declarative learning
34
What type of learning is associated with REM sleep?
procedural learning
35
What is the glymphatic system?
As it moves through the interstitial spaces, CSF clears waste products awaty before exiting into blood vessels
36
What is the waste removal theory of sleep?
- sleep is necessary for the brain to get rid of the waste that built up during the wakefulness stage
37
How does the correlation between baseline metabolic rate and sleep support the waste removal hypothesis of sleep?
- waste removal is favoured by economies of scale
38
What happens during sleep to allow for the glymphatic system to be more efficient?
- glial cells in the brain lose water and shrink in size
- the total volume of interstitial space increases
- the CSF diffuses more easily through the brain, allowing the clearance of waste
39
How does waste removal benefit from economies of scale?
- more space to accumulate waste
- clearance is faster than in smaller brains
40
What is the circadian rythm?
daily changes in behaviour and physiological processes that follows a cycle of approximately 24 hours. controls more interestingly the hormonal secretions as well as the sleep/wake cycles
41
What regulates the circadian rythm/activity level?
exposure to light
42
What happens if there is a change in exposure to light?
body adapts to the changes in exposure
43
What happens if there is no light exposure?
the circadian rythm is maintained, but may be a tad longer or shorter (never goes more than 25 or less than 23)
44
What regulates the sleep-wave cycles?
The suprachiasmatic nucleus
45
Where is the suprachiasmatic nucleus?
- In the hypothalamus
- right above the optic chiasm
46
What information does the suprachiasmatic nucleus recive and analyze?
- analyzes the quantity of light that is present
47
What happens if you lesion the suprachiasmatic nucleus?
Deregulates sleep schedules (length and timing)
Changes when you sleep, not how much you sleep
48
what maintains the circadian rythm?
- interlocking feedback loop of PER2 and PER3 proteins
49
How does the interlocking feedback loop of PER2 and PER3 function?
- when the expression of one protein is high enough, it inhibits its produciton and promotes the expression of another
50
What is the PER2 protein responsible for?
wakefulness
51
What is the PER3 protein responsible for?
sleepiness
52
What is caused by a mutation of the per2 gene?
- advanced sleep phase syndrome
53
What is the advanced sleep phase syndrome?
4-hour advance in the biological clock
54
What is caused by a mutation of the per3 gene?
- delayed sleep syndrome
55
What is the delayed sleep syndrome?
4-hour delay in the biological rythms
56
What is the sleep-molecule hypothesis?
the build-up of certain molecules in the brain during wakefulness promote sleepiness and drowsiness at high concentrations
57
What is adenosine?
- molecule whose levels rise during waking hours
- levels fall rapidly during sleep
58
What is the function of adenosine receptors through the brain?
modulates drowsiness
modulate the duration of sleep
modulate the depth of sleep
59
With what we know, what is the element that most likely determines the length of sleep?
molecular signaling (adenosine)
60
What is the chemical effect of caffeine?
adenosine receptor antagonist
61
What influences the neural circuits that regulate arousal?
suprachiasmatic nucleu neurons and the build up of sleep promoting molecules
62
What signaling molecules are released by neurons that are active during arousal/alertness/wakefulness?
- serotonin
- norepinephrine
- acetylcholine
- orexin
- histamine
63
Where is sleep-relevant serotonin produced?
Raphe nuclei in the hindbrain
64
Where is sleep-relevant norepinephrine produced?
locus coeruleus in the hindbrain
65
Where is sleep-relevant acetylcholine produced
hindbrain
66
Where is sleep-relevant acetylcholine produced?
throughout the brain
67
Where is sleep-relevant orexin produced?
hypothalamus
68
Where is sleep-relevant histamine produced?
hypothalamus
69
What happens considering the signaling molecules when the animal goes to sleep?
decrease in activity
70
What is the particularity of a flip flop circuit?
- both regions cannot be active at the same time (activity of one inhibits the other)
- switch from one state to another is fast
71
Where are situated the neurons that promote sleep?
ventral lateral preoptic area
72
Where are situated the neurons that promote wakefulness?
Brain stem and forebrain
73
What composes the flip-flop sleep circuit?
- sleep-promoting region in the ventrolateral preoptic area
- arousal systems f the brain stem and forebrain
74
What happens when the flip-flop circuit is "on"?
- brain stem and forebrain arousal systems are activated
- animal is awake
- secretion of activity-promoting signaling molecules
- ventrolateral preoptic area is inhibited
75
What happens when the flip-flop circuit is "off"?
- Sleep promoting region in the ventrolateral preoptic area is activated
- animal is asleep
- arousal systems are inhibited
76
What activates the ventrolateral preoptic area?
the activity of the adenosine that has built up during the day
77
What activates the arousal systems of the flip-flop circuit?
the secretion of orexin
78
What is the most frequent cause of narcolepsy?
absence of orexin neurons
79
What regulates the activation or not of REM sleep?
the REM flip-flop circuit
80
What region is active when the animal is in REM?
the sublateral dorsal nucleus
81
What is narcolepsy?
- sleep disorder caracterized by periods of excessive daytime sleepiness and irresistible urges to sleep
- the REM system comes on when it is not supposed to
82
What is the most likely cause of narcolepsy?
death of orexin neurons
83
What causes the death of orexin neurons?
the activity of a person's immune system
84
What are some symptoms of narcolepsy?
- irresistible urges to sleep
- sleep paralysis
- cataplexy (muscle paralysis when the person is awake)
85
What is the role of orexin?
Regulate wakefulness and arousal
86
What is insomnia?
difficulty falling asleep or going back to sleep
87
What is fatal family insomnia? Sporadic fatal insomnia?
progressively worstening states of insomnia
88
What are the symptons of fatal family insomnia and sporadic fatal insomnia?
- delirium
- confusional states
- death
89
What are the most likely causes of fatal family insomnia and sporadic fatal insomnia
- neurodegenaration around thalamus, hypothalamus and brain stem
90
What are the non-rem parasomnias?
sleep disorders where the brain seems to get caught between a sleepong and a waking state
91
What are some examples of non-rem parasomnia?
night terrors, sleep-walking, sleep-talking, etc.
92
What is the REM sleep behavior disorder?
neurological disorder where the person does not become paralyzed uring REM sleep, thus acts out dreams
93
What causes REM sleep behavior disorder?
it is a neurodegenerative disorder. has at least some genetic component
