Ch. 8- Wakefulness and Sleep Flashcards
(140 cards)
1
Q
endogenous circannual rhythm and
endogenous circadian rhythm
A
endogenous: coming from inside the animal/ not necessarily triggered by outside stimuli
circannual: yearly (birds flying north)
circadian: daily
2
Q
processes that follow the circadian rhythm in humans
A
sleep, body temperature, mood, hormones, and much more
3
Q
zeitgeber
A
stimuli that help setting and resetting the biological clock. Light is the important one for humans, other factors like activity, or food intake play a minor role. Lack of or problematic zeitgeber (e.g. in Antarctica) can lead to bad sleep and feeling unrested
4
Q
jet lag
A
disruption of circadian rhythms due to crossing time zones. Jet lag is stressful –> more cortisol –> long term repeated jet lag damages the hippocampus
5
Q
shift work
A
people often cannot adjust to working in the night
To improve adjustment the sleeping room must be very dark and the work place must have bright blueish light
6
Q
morning and evening types
A
the body temperature rhythm differs for people, some have their peek of activity in the midday, some have it later in the afternoon
7
Q
middle of sleep at different ages
A
the middle of sleep gets later and later until age 20, from which it starts to get earlier and earlier again
8
Q
social jet lag
A
teenagers that are evening types suffer under the early times school starts and get worse grades than pupils with comparable IQ
9
Q
the biological clock
A
the biological clock is endogene and works even when a person is deprived of light, food, has brain damages, takes drugs etc. It is quite robust. It slowly gets out of phase though when people do not get any indication of the day time
10
Q
main brain structure for rhythms of sleep and body temperature
A
Add to dictionary nucleus (SCN)
11
Q
properties of suprachiasmatic nucleus
A
lies just above the optic chiasm, works independent of the rest of the body,
12
Q
how does light influence the SCN
A
there are special ganglion cell at the eye, which slowly respond to light, and transmit the average light intensity right into the SCN. These ganglion cells even work with little information, for example for nearly blind people
13
Q
what are PER and TIM, and how do they work
A
They are proteins which promote sleep. Their production follows a negative feedback loop. Concentration is low in the morning, so they get produced. We (or flies actually) have the most of them in the night. A lot of PER and TIM sends messages to stop producing them. Therefore, the PER and TIM levels lower towards the morning. Light activates chemical to destroy these proteins
14
Q
melatonin
A
is a hormone that promotes sleep and thereby also influence circadian rhythms. It get released by the pineal gland, which in turn is controlled by the SCN
15
Q
distinction sleep and coma
A
sleep: actively produced by the brain, characterized by decreased responsibility to stimuli, but a loud noise still can wake people up
coma: extended period of unconsciousness caused by head trauma or the like. People cannot be woken up with a loud noise. Usually leads to death or recovery within
16
Q
vegetative state
A
alternate between sleep and moderate arousal, but never with awareness of surroundings or purposeful behavior. Can last a long time
17
Q
minimally conscious state
A
occasional brief periods of purposeful actions and limited amounts of speech and comprehension. Can last a long time
18
Q
brain death
A
no sign of brain activity or response to stimuli, for 24 hours
19
Q
EEG measurements
A
the eeg measures activity when most cells do the same thing, so no slight or small regional variations
20
Q
polysomnography
A
a combination of eeg and eye movements
21
Q
alpha waves
A
characteristic of relaxation, not of full wakefulness, frequency of 8 to 12 per second
22
Q
sleep spindle
A
12 to 14 hz waves during a birst that lasts at least half a second, results out of interactions between thalamus and cortex
23
Q
k-complex
A
a sharp wave associated with temporary inhibition of neuronal firing
24
Q
stage 1 sleep
A
irregular, jagged low voltage waves
25
stage 2 sleep
characterized by sleep spindles and k-complexes
26
sleep stage 3 and 4, aka slow-wave sleep
activity decreases, slow high voltage (amplitude) waves become more common. highly synchronized neuronal activity
27
paradoxical sleep
the same as rem sleep. was called this way because animals seemed highly relaxed (muscles) but active (brain) at the same time. We do not call rem sleep "deep" or "light" because of this, because this categorization would be misleading
28
non-rem sleep (NREM)
exactly that, just wanted to mention it
29
sleep cycle
stage 2 --> 3 --> 4 --> 3 --> 2 --> rem repeat
| early in the night longer 4 and 3, later longer rem
30
rem and dreams
rem seems to have more visual and intense dreams, but dreams can occur outside rem too
--> they are not the same
31
reticular formation
damaging this formation decreases brain arousal
it is located in the midbrain, and has axons down the spinal cord and up to the brain
a cut through this structure puts animals into days of sleep with only short periods awake
32
pontomesencephalon
part of the reticular formation
input: sensory information + spontaneous activity on its own
output: hypothalamus, thalamus, basal forebrain
maintains arousal during wakefulness
stimulation wakes sleeping animals up
33
locus coeruleus
small structure in the pons that increases attention
inactive during sleep
sends bursts of norepinephrine to emotional meaningful events
it increases activity of most active neurons and decreases activity of least active ones
enhanced attention to important information and enhanced memory
34
histamine
neurotransmitter, has an excitatory effect that increases arousal
released by the hypothalamus
35
orexin or hypocretin (same thing)
peptide neurotransmitter, necessary for staying awake
not necessary for waking up
released by the hypothalamus
36
basal forebrain
anterior dorsal to the hypothalamus
has axons that provide acetylcholine through the cerebral cortex and thalamus exiting it, but can also release gaba, inhibiting them
37
acetylcholine
tends to be excitatory, not released during slow-wave sleep, sharpens attention during wakefulness
38
how do we stay unconscious during sleep?
thalamus becomes hyperpolarized, decreasing its "information relay" function
GABA is released throughout the brain, which interferes with the spread of information from one neuron to the other
connections between brain areas become weaker
when stimulation does not spread, you don't become conscious of it
39
explain sleep walking and lucid dreams
sleep can occur in parts of the brain but not in others.
| sleep walkers for example are awake in the motor cortex and some other areas, lucid dreaming works similarly
40
the pons in rem
the pons makes sure that you do not move during rem sleep (except for eye and facial muscles). If you awake while the pons is still in rem, it is a very unpleasant experience
41
PGO-waves
Pons-geniculate-occipital. The geniculate is a nucleus in the thalamus. This wave occurs during REM and moves from P to G to O.
42
important neurotransmitters for rem sleep
it depends on the relationship between serotonin and acetylcholine. stimulating acetylcholine synapses moves people into rem quicker. Note: acetylcholine is important for both wakefulness and rem. Serotonin and norepinephrine interrupt rem sleep
43
insomnia
inadequate sleep. most adults need 7 1/2 to 8 hours. Reasons can be nearly anything. Most interesting one: circadian body temperature rhythm can be phase delayed (to actual sleeping times) --> problems falling asleep; or it can be phase advanced --> problems staying asleep
44
sleep apnea
impaired ability to breathe while sleeping. Causes them to awake in the nights, which leads to impaired attention, depression (a common symptom of sleep problems in general), even loss of neurons. Comes from genetics, hormones, obesity, old-age. Is treated through diet, no alc, surgery, or a breathing mask
45
symptoms narcolepsy
1 in a 1000 people, has a genetic component.
1. attacks of sleepiness during the day
2. occasional cataplexy, an attack of muscle weakness triggered by strong emotions
3. frequent sleep paralysis
4. Hypnagogic hallucinations, dreams that cannot be distinguished from reality, at the onset of sleep
46
causes narcolepsy
lack of hypothalamic cells that produce and release orexin --> less orexin (which is important for maintaining wakefulness) --> frequent alternations between wakefulness and sleep
-the lack of hypothalamic cells might be due to an autoimmune reaction, where the immune system destroys theses cells
47
periodic limb movement disorder
involuntary movement of the limbs during sleep. Middle aged people mostly, kick once every 20-30 seconds during nrem
48
rem behavior disorders
moving vigorously during rem, acting out the dream. Often injure themselves or others. GABA not working properly might be the explanation
49
night terrors
intense anxiety from which a person awakens screaming in terror. A night terror is more severe than a nightmare, which is simply an unpleasant dream. Night terrors occur during NREM sleep and are more common in children than adults. Dream content, if any, is usually simple, such as a single image
50
sleep walking
Sleepwalking runs in families and occurs mostly in children. Most people who sleepwalk, and many of their relatives, have one or more additional sleep difficulties such as chronic snoring, disordered sleep breathing, bed-wetting, and night terrors. The causes of sleepwalking are not well understood, but it is more common when people are sleep deprived or under unusual stress. It is most common during slow-wave sleep early in the night and usually not accompanied by dreaming. usually harmless, but not always. Parts of the brain are asleep while others are awake. not dangerous to wake them up
51
sexsomnia
An analogous condition is sleep sex or “sexsomnia,” in
which sleeping people engage in sexual behavior, either with a partner or by masturbation, and do not remember it afterward. Sexsomnia poses a threat to romances and marriages
52
sleeps original function
to save energy. There are times where we can work efficiently and times where we cant, and when we cant we should conserver our energy (night for example). The decrease in body temperature saves energy. In that sense, sleep can be compared to hibernation
53
hibernation
body functions get shut down as much as possible. it retards the aging process
54
species differences in sleep
deep sea fish appear to never sleep. Other animals might have special times in their lives, migrating birds or dolphins after giving birth, where their need for sleep greatly decreases or vanishes completely. Overall we can say that the amount of sleep an animals gets seems to fit in well with the animals need to conserve energy. animals that must spend their whole day grazing sleep less than animals that can fill their nutritional needs in a short hunt.
55
sleeps influence on memory
sleep helps retrieve memories, it helps consolidating new memories, it helps reanalyzing memories
56
how does sleep improve memory
in sleep, fast activity in the hippocampus that resembles the activity during learning. The brain replays its daily experiences but with no clear pattern, so the role of hippocampal activity is not really clear. The brain also weakens less appropriate (less used synapses) during sleep, thereby emphasizing the synapses that do get used during wakefulness. Sleep spindles seem to contribute too. They also correlate highly (0.7) with IQ
57
amount of rem sleep across species and age
the longer a species sleeps, the higher the percentage of rem.
this is the same over age. With age, the total amount of sleep decreases and the relative amount of rem decreases to. Although rem is certainly important, nrem is more tightly regulated.
58
functions of rem
One hypothesis is that REM is important for memory storage, especially for weakening the inappropriate connections. REM and non-REM sleep may be important for consolidating different types of memories. Depriving people of sleep early in the night (mostly non-REM sleep) impairs verbal learning, such as memorizing a list of words, whereas depriving people of sleep during the second half of the night (more REM) impairs consolidation of learned motor skills. Maybe, we just need to arouse the body to shake our eyeballs, so that we can increase oxygen supply to corneas. Sounds odd, but might be
59
the activation-synthesis hypothesis
tries to explain dreams. a dream represents the brain’s effort to make sense of sparse and distorted information. PGO waves activate some cortex areas in a [willkürlich] fashion, and the brain creates a story to make sense of it all. Can explain some sorts of dreams (dreams of falling make sense of the vestibular sensations due to lying on a bed), but it is criticized for having too vague predictions
60
the clinic-anatomical hypothesis
also emphasized the connection of more or less random brain patterns that occur during sleep, but with less emphasis on the PGO waves.
Thinking that takes place under unusual conditions.
Little sensory input + inhibited working memory lead to free associations without much constraint, which are also quickly forgotten. We also loose our sense of planning.
So the idea is that either internal or external stimulation
activates parts of the parietal, occipital, and temporal cortex. The arousal develops into a hallucinatory perception, with no sensory input from area V1 to override it. Hard to test as well
61
suppose you fell into a cave and lost your watch. Without any time cues, your circadian rhythm would
remain relatively stable
62
Researchers have demonstrated that the expression of the SCN genes can be changed through
exposure of the eyes to light
63
Based on research it has been determined that the human circadian rhythm appears to be
Just over 24 hours
64
If the suprachiasmatic nucleus neurons are disconnected from the rest of the brain they
Continue to produce activity that follows the circadian rhythm
65
Social stimuli that is the effects of other people are weak unless they induce exercise or other vigorous activity
Zeitgebers
66
A humans body temperature over the course of 24 hours is usually highest
Mid to late afternoon
67
What is the principal Zeitgeber for land animals
light
68
The SCN is located just above the
Optic chiasm
69
An astronaut orbiting earth experiences 45 minute periods of daylight alternating with 45 minute periods of darkness what is likely to happen
They sleep poorly during rest periods
70
When traveling across time zones how does the direction of travel affect one's adjustment to the new time zone
Travel to the west is easier
71
Research on circadian rhythm's has shown that one of the best ways to increase the alertness and efficiency of workers on night shift's is to
Expose them to bright lights while they work
72
Suppose you work on a submarine with only artificial light you're required to follow a schedule of working for 12 hours and then sleeping for six what rhythm if Annie will your alertness and body temperature show
They will follow the usual rhythm of 24 hours
73
what does endogenous mean
generated from within
74
a Zeitgeber is an
environmental cue that resets a biological clock
75
what is the role of the suprachiasmatic nuclear in circadian rhythms
its neurons generate a 24 hour rhythm by themselves
76
animals produce endogenous circadian rhythms that last
about a day
77
a small branch of the optic nerve, known as the ____ path extends directly from the retina to the SCN
retinohypothalamic
78
The suprachiasmatic nucleus is found in the
hypothalamus
79
Circadian rhythm is reset by input from special ganglion cells in the retina these ganglion cells are unusual in that they
Respond directly to light the respond very slowly
80
The SCN produces circadian rhythms by altering
production of proteins
81
a persons circadian activity cycle would most likely drift out of phase with the activity of other people if the person
spends a period of time in seclusion, away from sunlight
82
which of the following is most clearly under the control of a circadian rhythm in most animals
sleep
83
the pineal gland releases the ____ hormone, which influences both circadian and circannual rhythms
melatonin
84
the proteins PER and TIM, originally discovered in insect but now found in mammals also, influence circadian rhythms by
building up during the day and declining during sleep
85
mammals have circadian rhythms
for a variety of activities, including sleep
86
Which statement is TRUE with regard to the duration of a self generated sleep activity cycle
it is highly consistent in a given individual in a. given environment
87
what happens after damage to the suprachiasmatic nucleus itself
animals activity patterns become less consistent and no longer respond to light and dark cycles
88
When do the secretions of melatonin begin
a couple hours before a person naturally falls asleep
89
typically, a person who galls asleep enters
stage 1 and slowly progresses through stages 2,3,and 4 in order
90
research found that during REM sleep, activity
increased in both the pons and the limbic system
91
someone in a ____ state between periods of sleep and moderate arousal, although even during the more aroused state, the person shows no awareness of surroundings and no purposeful behavior
vegetative
92
in comparison to NREM dreams, REM dreams
are more likely to include complicated plots
93
which of the following increases risk of sleep apnea
being obese
94
for a normal person, about how long does a cycle of sleep from stage 1-4 and back again last
90 minutes
95
one part of the reticular formation that contributes to cortical arousal is known as the
pontomesencephalon
96
a person who is taking an antidepressant that increases serotonin or norepinephrine levels in the brain is most likely to have
interrupted or shortened REM sleep
97
slow wave sleep is comprised of
stages 3 and 4
98
orexin, produced by neurons in the hypothalamus, appears to be necessary for
staying awake
99
what are the dreamlike experiences at the onset of sleep that are difficult to distinguish from reality
hypnagogic hallucinations
100
with each succeeding stage of sleep
slow, large amplitude waves increase in number
101
the sequence of the bursts of neural activity during REM sleep is
pins, lateral geniculate nucleus, and occipital cortex
102
with regard to sleep and arousal, the locus coeruleus is
almost completely inactive during sleep
103
alpha waves are characteristic of what type of activity
relaxed wakefulness
104
PGO waves are associated with
REM sleep
105
which condition has often been interpreted as an intrusion of REM sleep into wakefulness
narcolepsy
106
loss of orexin-containing neurons in the hypothalamus may contribute to
narcolepsy
107
the relationship between sleep stage and dreaming is that dreams
are more frequent and more vivid in REM sleep
108
what is a typical characteristic of insomnia
consistently feeling sleepy during the day
109
during sleep what happens in the brain
increased firing by GABA neurons `
110
which of these is characteristic of sleep apnea
period without breathing during sleep
111
it appears from research with cats that one function of the messages from the pons to the spinal cord is to prevent us from
acting out our dreams
112
sleep singles and K complexes are most characteristic of which sleep stage
stage 2
113
during ____, cells in the pins send messages that inhibit the motor neurons that control the bodys large muscles
REM sleep
114
what is the best way to determine if an individual who claims to never dream does, in fact, have dreams
wake them up during REM sleep and ask them if they have been dreaming
115
During REM sleep, the EEG shows
irregular low voltage fast waves
116
what is narcolepsy
sudden periods of sleepiness during the day
117
some drugs use to read allergies may produce drowsiness if they
block histamine
118
when does sleep walking occur
mostly during slow wave sleep
119
what does cataplexy involve
an attack of muscle weakness while awake
120
repeated involuntary movements of the arms and legs that may prevent a person from calling asleep are known as
periodic limb movement disorder
121
cells in the basal forebrain increase arousal and wakefulness by releasing
acetylcholine
122
REM sleep is characterized by which of the following
a high level of brain activity
123
people with REM behavior disorder
move vigorously during REM apparently acting out their dreams
124
what do the EEG waves look like when brain activity is desynchronized
irregular waves with low amplitude
125
In response to emotionally arousing events, the locus coeruleus releases
norepinephrine
126
compared to the earlier part, the later part of a nights sleep
includes a larger percentage of REM sleep
127
EEG waves are larger when brain activity decreases because
neurons are becoming more synchronized
128
sometimes people find themselves unable to move their postural muscles immediately after awakening Why?
part of the brain is still asleep
129
what is paradoxical about paradoxical sleep
it is light sleep in some ways and deep sleep in other ways
130
night terrors can be distinguished from nightmares in that night terrors
occur during NREM sleep
131
Young adults deprived of a nights sleep show deficits on ____ tasks
memory
132
which hypothesis/theory suggests that the primary motor cortex is suppressed so arousal during sleep cannot lead to action
a clinics-anatomical hypothesis
133
if we compare either different species or different ages, what trend emerges
the more total sleep, the higher the percentage of REM sleep
134
A decrease in the amount of sleep most likely to affect the performance of migratory bird during
seasons other migrations
135
according to the activation-synthesis hypothesis, what do dreams reflect
the brains attempt to make sense of spontaneous neural activity
136
compared to REM, research suggests that NREM is
important for strengthening memories of lists of words
137
research suggests that REM is
most important for strengthening memories of motor skills
138
a recent hypothesis proposed that the role of REM is
to shake the eyeballs back and forth in order to get sufficient oxygen to the corneas of the eyes
139
another aspect of sleeps contribution to memory relates to
sleep spindles
140
according the the activation-synthesis hypothesis, it should be possible to predict the content of a persons dreams if we know what information about the person
stimuli currently acting on the body and areas of spontaneous brain activity
