Sleep Flashcards
(98 cards)
1
Q
What is a circadian rhythm?
A
variation in physiological processes that cycles in a ~24 hour period
2
Q
What are some physiological changes that follow a circadian rhythm?
A
body temperature, melatonin levels, alertness
3
Q
What rhythm is followed by people when left in the absence of time cues?
A
free-running rhythms
4
Q
Why don’t humans usually free-run?
A
time cues (sunlight, alarm clock) reset our internal clock every day
5
Q
What is an ultradian rhythm?
A
a cycle that lasts less than 24 hours
6
Q
What type of rhythm do sleep stages follow?
A
ultradian
7
Q
How do typical free-running rhythms compare to circadian rhythms?
A
free-running rhythms are slightly longer
8
Q
What do EEG readings indicate during sleep?
A
changes in brain activity
9
Q
What waves do EEG scans show when someone is awake?
A
beta waves
10
Q
When do EEG scans show alpha waves?
A
when awake but relaxed and drowsy
11
Q
How many stages make up non-REM sleep?
A
4
12
Q
What brain waves are seen in non-REM sleep?
A
theta and delta
13
Q
What brain waves are seen during REM sleep?
A
beta-like waves
14
Q
What are the characteristics of beta waves?
A
rapid, low-energy waves?
15
Q
How do alpha waves compare to beta waves?
A
slower
16
Q
How do theta waves compare to alpha waves?
A
slower, lower energy
17
Q
What characteristics does REM sleep share with wakefulness?
A
- increased heart rate, blood pressure, respiration
- muscle twitching (fingers and face)
- eyes move around (under lids)
18
Q
What is muscle tension during REM sleep?
A
very relaxed - almost paralyzed
19
Q
Why might it be a benefit for muscle tension to be relaxed during REM sleep?
A
to prevent injury from acting out dreams
20
Q
What happens when a person first enters stage 1 sleep?
A
- brain changes to theta waves
- become less responsive to outside world
21
Q
How much is needed to wake up someone in stage 1 sleep vs. a later stage?
A
not much needed to wake up from stage 1
22
Q
What brain waves dominate stage 2 sleep?
A
theta waves
23
Q
What stages of sleep are dominated by delta waves?
A
stages 3 and 4
24
Q
What happens after reaching stage 4 sleep for the first time?
A
brain transitions back to stage 1, where REM sleep occurs
25
How many sleep cycles does an adult have during a typical night?
4-6 cycles
26
How does the length of REM sleep change as more sleep cycles are completed in one night?
it lengthens
27
How does the amount of time spent in non-REM sleep as a night progresses?
it decreases
28
What is the acoustic arousal threshold?
amount of sound required for awakening
29
What is used to characterize sleep depth?
acoustic arousal threshold and EEG
30
How does the time spent in REM sleep change over a lifetime?
time spent in REM decreases sharply from birth and childhood, continuing to trop as we age
31
How does the time spent in non-REM sleep change as we age?
decreases slightly
32
What is a possible reason to explain why children spend more time in REM sleep than adults?
REM sleep assists in brain growth and development
33
How does sleep structure vary between long sleepers (>8.5 hours) and short sleepers (<6.5 hours)?
long sleepers spend more time in REM/stage 1 and 2 sleep than short sleepers, whereas stage 3/4 sleep time doesn't change
34
What happens to sleep deprived organisms?
physical deterioration, inhibited neural growth, impaired memory
35
What is the restoration theory of sleep?
sleep is necessary for physical restoration of cells in body
36
How does the body get damaged during the day?
oxygen metabolism produces harmfull free radicals in cells
37
How can sleep repair physical damage?
produces enzymes to fight cell damage
38
What is some support for the restoration theory?
sleep deprivation leads to breakdown of tissues; sleep more after a marathon
39
How did sleep structure vary between control groups and people who exercised 30 minutes or 60 minutes at their maximum intensity threshold?
it was mostly preserved - only a minor difference in stage 1 sleep (less time spent in stage 1 for those who exercised)
40
What does WASO stand for?
wake after sleep onset
41
How did WASO vary between controls and people who exercised 30 or 60 minutes?
WASO was lower for those who exercised
42
What are two measures of sleep quality?
WASO (wake after sleep onset) and latency
43
What is sleep latency?
the length of time it takes to fall asleep
44
How long does it usually take to fall asleep?
15-20 minutes
45
What is the memory consolidation theory?
sleep enhances learning and memory
46
According to the memory consolidation theory, what does the brain do during sleep?
rehearses new tasks (hippocampus activity seen when learning something is repeated during slow-wave sleep - neurons fire in same pattern)
47
What is some support for the memory consolidation theory?
sleep architecture changes with learning, and sleep deprivation reduces learning improvement
48
How does sleep architecture change after learning something new?
increased REM sleep
49
How does improvement in learning a task relate to sleep?
less sleep, less improvement
50
What effect does chronic sleep restriction have on cognitive function?
it produces cognitive impairments
51
What does 4 hours of sleep restriction per night over two weeks correspond to?
2 days of total sleep deprivation
52
What is sleep debt?
the amount of sleep our brain owes our body
53
How does sleep debt get paid back?
by increases in slow wave sleep (not total sleep time)
54
How does sleep restriction to 4/6 hours a night differ from total sleep deprivation in terms of sleepiness ratings over time?
sleepiness increases very sharply for total deprivaiton while it gradually increases over time for 4/6 hours
55
How does sleep architecture change when sleep is restricted?
slow wave sleep time stays constant, while stages 1 and 2 time are decreased
56
What are some signs of sleep deprivation?
needing an alarm clock to wake, sleeping longer on weekends, falling asleep during lectures
57
What are insomnia, sleep apnea, sleepwalking, narcolepsy, and hypersomnia?
sleep disorders
58
What is insomnia?
sleep difficulty characterized by difficulty falling and staying asleep, as well as not feeling rested
59
What are some possible causes of insomnia?
restless leg syndrome, erratic hours, medical conditions, psychological disorders, alcohol/drug use, iron deficiency
60
How can insomnia be treated?
increase effect of GABA
61
How does increasing GABA's effect help treat insomnia?
it decreases CNS activity, producing a general feeling of relaxation
62
What is the problem with treating insomnia with GABA?
the brain can adapt to GABA's inhibitory effects by making neurons less excitable, which causes rebound insomnia when drug use is stopped
63
What is sleep apnea?
sleep difficulty that ersults from temporary blockage of air passage
64
What sleep disorder is more common in men and obese people?
sleep apnea
65
How does sleep apnea affect one's sleep structure?
lack of deep sleep and REM sleep - sleep deprived
66
What sleep disorder increases the risk of car accidents, diabetes, and heart disease
sleep apnea
67
How can sleep apnea be treated?
weight loss, surgery, devices that keep throat open
68
What is sleepwalking?
sleep difficulty characterized by activities occurring during non-REM sleep that usually occur when awake
69
Why can't sleepwalking occur during REM sleep?
muscle activity is inhibited during REM
70
What sleep disorder is more common in children?
sleepwalking
71
What is narcolepsy?
sleep disorder characterized by excessive daytime sleepiness and weakness in facial and limb muscles
72
What is a term to describe a weakness in facial and limb muscles?
cataplexy
73
What does a defecit of orexin cause?
narcolepsy
74
What is orexin?
neurotransmitter important for arousal
75
What sleep disorder has a genetic basis and why?
narcolepsy - caused by lack of orexin
76
What are amphetamines and antidepressants used to treat, and what aspects of the disorder do they deal with?
narcolepsy; amphetamines help prevent daytime sleepiness and antidepressants help with cataplexy
77
What is hypersomnia?
sleep difficulty characterized by sleeping more than 10 horus a day for 2+ weeks, including the urge to nap during inappropriate times
78
What can apnea, brain injury, and/or depression cause?
hypersomnia
79
What sleep disorder is correlated with suicidal adolescents?
hypersomnia
80
What are dreams?
images, thoughts, and feelings experienced during sleep
81
What dream theory states that dreams are "the royal road to the unconscious?
Freud's psychoanalytic theory
82
What are the two levels of access of dreams, according to Freud?
manifest level and latent level
83
What is the manifest level of dreams?
what you actually dream - the surface level, recalled upon waking
84
What is the latent level of dreams?
the deeper unconscious level, where true meaning lies
85
What does Freud think the latent level of dreams reveals?
hidden conflicts
86
What evidence does the memory consolidation theory present to indicate that dreaming (REM) supports memory functions?
new learning increases amount of REM, while REM deprivation impairs certain types of memory and synaptic plasticity
87
Other than REM, what is important for some types of learning?
non-REM sleep
88
What role does the suprachiasmatic nucleus (SCN) play?
internal timekeeper - regulates physiological activity on daily cycles
89
Where is the suprachiasmatic nucleus located?
hypothalamus
90
What structure keeps the body's circadian rhythms on track?
SCN
91
How does the SCN regulate alertness in the morning?
1. retina in eye senses morning light
2. stimulates SCN
3. sends signals to pineal gland to decrease amount of melatonin levels released
92
How does the SCN regulate alertness in the evening?
1. SCN activity decreases
2. more melatonin secreted
3. increased relaxation
93
What is melatonin?
hormone with role in relaxation/drowsiness
94
What can melatonin be taken to combat?
jet lag
95
What neurotransmitter is found in neurons in the basal forebrain?
acetylcholine
96
What effect does acetylcholine have on the brain in regards to sleep?
produces rapid EEG activation patterns observed in waking and REM sleep
97
Do neurons in the preoptic area promote or inhibit sleep and what neurotransmitters do they contain?
promote sleep (GABA)
98
What part of the brain contains orexin neurons?
posterior hypothalamus
