Sleep and Circadian Rhythms Flashcards

1
Q

What is 5-hydroxytryptophan (5-HTP?

A

the precursor of serotonin

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2
Q

What is the activation-synthesis hypothesis?

A

the theory that the information supplied to the cortex by the brain stem during REM sleep is largely random and that the resulting dream is the cortex’s best effort to make sense of those random signals

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3
Q

What are the adaptation theories of sleep?

A

theories of sleep based on the premise that sleep evolved to protect organisms from predation and accidents and to conserve their energy rather than to fulfil some particular physiological need

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4
Q

What are alpha waves?

A

Regular, 8- to 12-per-second, high-amplitude EEG waves that typically occur during relaxed wakefulness and just before falling asleep

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5
Q

What are antihypnotic drugs?

A

sleep-reducing drugs

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6
Q

What are benzodiazepines?

A

a class of GABAa agonists with anxiolytic, sedative, and anticonvulsant properties; drugs such as chlordiazepoxide (Librium) and diazepam (Valium)

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7
Q

What is a carousel apparatus?

A

an apparatus used to study the effects of sleep deprivation in laboratory rats

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8
Q

What is cataplexy?

A

a disorder that is characterised by recurring losses of muscle tone during wakefulness and is often seen in cases of narcolepsy

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9
Q

What is cerveau isole preparation?

A

an experimental preparation in which the forebrain is disconnected from the rest of the brain by a midcollicular transection

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10
Q

What is a chronobiotic?

A

a substance that influences the timing of internal biological rhythms

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11
Q

What is a circadian clock?

A

an internal timing mechanism that is capable of maintaining daily cycles of physiological functions

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12
Q

What are circadian rhythms?

A

daily cycles of bodily functions

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13
Q

What are delta waves?

A

the largest and slowest EEG waves

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14
Q

What is a desychronised EEG?

A

low-amplitude, high-frequency EEG

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15
Q

What is an electroencephalogram (EEG)?

A

a measure of the gross electrical activity of the brain, commonly recorded through scalp electrodes

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16
Q

What is a electromyogram (EMG)?

A

a record of muscle tension

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17
Q

What is an electrooculogram (EOG)?

A

A measure of eye movement

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18
Q

What is emergent stage 1 EEG?

A

all periods of stage 1 sleep EEG except initial stage 1; each is associated with REMs

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19
Q

What is encephale isole preparation?

A

an experimental preparation in which the brain is separated from the rest of the nervous system by a transection of the caudal brain stem

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20
Q

What is executive function?

A

a collection of cognitive abilities (e.g., innovative thinking, lateral thinking and insightful thinking) that appear to depend on the prefrontal cortex

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21
Q

What is a free-running period?

A

the duration of one cycle of a free-running rhythm

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22
Q

What are free-running rhythms?

A

circadian rhythms that do not depend on environmental cues to keep them on a regular schedule

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23
Q

What is hypersomnia?

A

disorders characterised by excessive sleep or sleepiness

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24
Q

What are hypnagogic hallucinations?

A

dreamlike experiences that occur during wakefulness

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25
Q

What are hypnotic drugs?

A

sleep-promoting drugs

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26
Q

What does iatrogenic mean?

A

physician-created

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27
Q

What are imidazipyridines?

A

a class of GABAa agonists that were marketed for the treatment of insomnia

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28
Q

What is initial stage 1 EEG?

A

the period of the stage 1 EEG that occurs at the onset of sleep; it is not associated with REMs

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29
Q

What is insomnia?

A

Sleeplessness

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30
Q

What is internal desynchronisation?

A

the cycling on different schedules of the free-running circadian rhythms of two or more different processes

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31
Q

What is jet lag?

A

the adverse effects on bodily function of the acceleration of zeitgebers during eastbound flights or their deceleration during westbound flights

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32
Q

What is melanopsin?

A

photopigment found in certain retinal ganglion cells that responds to changes in background illumination and plays a role in the entrainment of circadian rhythms

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33
Q

What is melatonin?

A

a hormone that is synthesised from serotonin in the pineal gland, and is both a soporific and a chronobiotic

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34
Q

What are microsleeps?

A

brief periods of sleep that occur in sleep-deprived subjects while they remain sitting or standing

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35
Q

What are monophasic sleep cycles?

A

sleep cycles that regularly involve only one period of sleep per day, typically at night

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36
Q

What is narcolepsy?

A

a disorder of hypersomnia that is characterised by repeated, brief daytime sleep attacks and cataplexy

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37
Q

What is the nucleus magnocellularis?

A

the nucleus of the caudal reticular formation that promotes relaxation of the core muscles during REM sleep and during attacks of cataplexy

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38
Q

What is orexin?

A

a neuropeptide that has been implicated in narcolepsy; sometimes called hypocretin

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39
Q

What is periodic limb movement disorder?

A

characterised by periodic, involuntary movements of the limbs often involving twitches of the legs during sleep; one cause of insomnia

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40
Q

What is the pineal gland?

A

the endocrine gland that is the human body’s sole source of melatonin

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41
Q

What are polyphasic sleep cycles?

A

sleep cycles that regularly involve more than one period of sleep per day

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42
Q

What are recuperation theories of sleep?

A

theories based on the premise that being awake disturbs the body’s homeostasis and the function of sleep is to restore it

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43
Q

What is REM sleep?

A

the stage of sleep characterised by rapid eye movement, loss of core muscle tone and emergent stage 1 EEG

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44
Q

What is REM-sleep behaviour disorder?

A

a disorder where the individual experiences REM sleep without core-muscle atonia

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45
Q

What is restless legs syndrome?

A

tension of uneasiness in the legs that keeps a person from falling asleep; one cause of insominia

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46
Q

What is the reticular activating system?

A

the hypothetical arousal system in the reticular formation

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47
Q

What is sleep apnea?

A

a condition in which sleep is repeatedly disturbed by momentary interruptions in breathing

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48
Q

What is sleep inertia?

A

the unpleasant feeling of grogginess that is sometimes experienced for a few minutes after waking

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49
Q

What is sleep paralysis?

A

a sleep disorder characterised by the inability to move (paralysis) just as a person is falling asleep or waking up

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50
Q

What is slow-wave sleep (SWS)?

A

stage 3 sleep, which is characterised by the largest and slowest EEG waves (delta waves)

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51
Q

What is the suprachiasmatic nuclei (SCN)?

A

nuclei of the medial hypothalamus that control the circadian cycles of various body functions

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52
Q

What is tau?

A

the first circadian gene to be identified in mammals

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53
Q

What are zeitgebers?

A

environmental cues, such as light-dark cycle, that entrain circadian rhythms

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54
Q

What are the three standard psychophysiological measures of sleep?

A

EEG
EOG
EMG

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55
Q

According to the American Academy of Sleep Medicine, how many stages of sleep are there?

A

Three

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56
Q

What are the characteristics of brain waves during stage 1 of sleep?

A

Low-voltage, high-frequency signals that is similar to, but slower than, that of alert wakefulness

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57
Q

What are the characteristics of brain waves during stage 2 of sleep?

A

Higher-amplitude and lower-frequency signals compared to stage 1.
K complexes and sleep spindles also feature

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58
Q

A single large negative wave followed immediately by a single large positive wave experienced during stage 2 is called what?

A

A K complex

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59
Q

A 0.5 - 3-second waxing and waning burst of 9- to 15-Hx waves experienced during stage 2 is called what?

A

A sleep spindle

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60
Q

What waves feature during stage 3 of sleep?

A

Delta waves

61
Q

True or False:

REMs can be seen during initial stage 1 EEG

A

False

REMs are experienced only during emergent stage 1 EEG

62
Q

How long is each sleep cycle?

A

Around 90 minutes

63
Q

True or False:

Antidepressants greatly reduced REM sleep without affecting aspects of dream recall

A

True

64
Q

True or False:

Dreaming is unaffected by cortical lesions

A

False

Cortical lesions can abolish dreaming without affecting REM sleep

65
Q

What is somniloquy?

A

Sleeptalking

66
Q

What is somnambulism?

A

Sleepwalking

67
Q

When does sleeptalking usually occur?

A

Usually during the transition to wakefulness but it can occur during any stage

68
Q

When does sleepwalking occur?

A

Usually during slow-wave sleep (never during REM)

69
Q

What did Freud believe dreams represented?

A

Dreams are triggered by unaccepted repressed wishes, often of a sexual nature

70
Q

What are the two kinds of theories of sleep?

A

Recuperation theories

Adaption theories

71
Q

What are the four main conclusions of the comparative analysis of sleep?

A

Sleep serves some important physiological function
The primary function of sleep is not some special, higher-order human function
Although sleep may be essential for survival, it is not necessarily needed in large quantities
There is no relationship between a species’ sleep time and its level of activity

72
Q

What is a common confounder in sleep deprivation studies?

A

Stress

73
Q

What are the three predictions that recuperation theories make about the effects of sleep deprivation?

A

Long periods of wakefulness will produce physiological and behavioural disturbances
These disturbances will grow worse as the sleep deprivation continues
After a period of deprivation has ended, much of the missed sleep will be regained

74
Q

What are the effects of moderate sleep deprivation (loss of 3 to 4 hours) in humans?

A

Increased sleepiness
Decreased mood regulation
Decreased performance on tasks requiring attention

75
Q

What types of cognitive function seem to be immune to sleep deprivation?

A

Logical deduction and critical thinking

76
Q

What types of cognitive function seem to be susceptible to sleep deprivation?

A

Executive function

77
Q

What are the physiological effects of sleep deprivation?

A
Reduced body temperature
Increased blood pressure
Decreased immunity
Hormonal changes
Metabolic changes
78
Q

How many days of sleep deprivation are usually required before microsleeps occur?

A

2 to 3 days

79
Q

What is a criticism of the carousel apparatus?

A

It may be that repeatedly being awakened by this apparatus kills the experimental rats not because it keeps them from sleeping but because it is stressful

80
Q

What is REM rebound?

A

A phenomenon that occurs following a period of REM-sleep deprivation where an individual has more than their usually amount of REM sleep for the first two or three nights

81
Q

What is the default theory of REM sleep?

A

It is difficult to stay continuously in NREM sleep, so the brain periodically switches to one of two other states. If there are any immediate bodily needs to be taken care of, the brain switches to wakefulness; if there are no immediate needs, it switches to REM sleep.

82
Q

REM sleep is characterised by rapid eye movement, loss of core muscle tone, and _______

A

Emergent stage 1 EEG

83
Q

________ believed that dreams are triggered by unaccepted repressed wishes

A

Sigmund Freud

84
Q

Freud referred to dreams that we experience as _______

A

Manifest dreams

85
Q

The _________ hypothesis states that the information supplied to the cortex during REM sleep is largely random, and the resulting dream is the cortex’s effort to make sense of random signals

A

Activation-synthesis

86
Q

_______ are brief periods of sleep that are typically about two or three seconds long

A

Microsleeps

87
Q

The effects of sleep deprivation are often difficult to study because they are often confounded by ______

A

Stress

88
Q

Convincing evidence that REM-sleep deprivation does not produce severe memory problems comes from the study of patients taking certain _________ drugs

A

Antidepressant

89
Q

After a lengthy period of sleep deprivation (e.g. several days), a person’s first night of sleep is only slightly longer than usual, but it contains a much higher proportion of ______ waves

A

Slow or delta

90
Q

________ sleep in particular, rather than sleep in general, appears to play the major restorative role

A

Slow-wave (or stage 3)

91
Q

Environmental cues, such as the light-dark cycle, that can entrain circadian rhythms are called _______

A

Zeitgebers

92
Q

What are the symptoms caused by jet lag and shift work?

A

Sleep disturbances, fatigue, general malaise, and deficits on tests of physical and cognitive function

93
Q

How can someone reduce the disruptive effects of jet lag?

A

Gradually shifting one’s sleep-wake cycle in the days prior to the flight
Administering treatments after the flight that promote the required shift in the circadian rhythm (i.e. melatonin)

94
Q

Lesions to the suprachiasmatic nuclei results in what?

A

Disruption of various circadian cycles

95
Q

True or False:
Under certain conditions, bilateral SCN lesion have been shown to leave some circadian rhythms unaffected while abolishing others

A

True

96
Q

True or False:

Bilateral SCN lesions eliminate the ability of all environmental stimuli to entrain circadian rhythms

A

False

They do not eliminate it

97
Q

What happens when you cut the optic nerve before the optic chiasm?

A

The light-dark cycle can no longer entrain circadian rhythms

98
Q

What happens when you cut the optic nerve after the optic chiasm?

A

The light-dark cycle is still able to entrain circadian rhythms

99
Q

What are retinohypothalamic tracts?

A

Nerves that leave the optic chiasm and project towards the SCN that mediate the ability of light to entrain circadian rhythms

100
Q

True or False:

Rod and cones are not required for entrainment of circadian rhythms

A

True

101
Q

What cells in the eye detect the light responsible for circadian rhythm entrainment?

A

Retinal ganglion cells

102
Q

What photopigment do retinal ganglion cells have?

A

Melanopsin

103
Q

What was the first circadian rhythm gene to be discovered?

A

Tau

104
Q

Which parts of the brain promote sleep?

A

Anterior hypothalamus and adjacent basal forebrain

105
Q

Which parts of the brain promote wakefulness?

A

Posterior hypothalamus and adjacent midbrain

106
Q

What are the effects of a cerveau isole preparation?

A

Continuous slow-wave sleep

107
Q

Low levels of activity in the reticular formation produce _______ and high levels produce ________

A

Sleep; wakefulness

108
Q

Which part of the brain controls REM sleep?

A

A variety of nuclei scattered thoughout the caudal reticular formation. Each site is responsible for controlling one of the major indices of REM sleep

109
Q

_________ means lasting about one day

A

Circadian

110
Q

Free-running rhythms are those that occur in environments devoid of _______

A

Zeitgebers

111
Q

The major circadian clock seems to be located in the _______ nuclei of the hypothalamus

A

Suprachiasmatic

112
Q

The ______ tracts conduct information about light-dark cycles to the SCN

A

Retinohypothalamic

113
Q

The first mammalian circadian gene to have its structure characterised was ________

A

Clock

114
Q

Patients with damage to the _________ hypothalamus and adjacent basal forebrain often have difficulty sleeping

A

Anterior

115
Q

Damage to the _________ hypothalamus and adjacent areas of the midbrain often cause excessive sleepiness

A

Posterior

116
Q

The low-amplitude high-frequency EEG of wakefulness is said to be ________

A

Desynchronised

117
Q

In Bremer’s classic study, cats with a _________ preparation displayed an EEG characteristic of continuous slow-wave sleep

A

Cerveau isole

118
Q

The indices of REM sleep are controlled by a variety of nuclei located in the caudal ________

A

Reticular formation

119
Q

What are drugs that increase sleep called?

A

Hypnotic drugs

120
Q

What are the complications of benzodiazepines as a hypnotic drug?

A
Tolerance
Withdrawal symptoms (insomnia)
Normal sleep pattern disruption 
Following day drowsiness
Reduction of life expectancy
121
Q

What are three classes of hypnotic drugs?

A

Benzodiazepines
Imidazopyridines
5-hydroxytryptophan (5-HTP)

122
Q

What are three classes of antihypnotic drugs?

A

Cocaine-derived stimulants
Amphetamine-derived stimulants
Tricyclic antidepressants

123
Q

What are side-effects of antihypnotic drugs?

A

Loss of appetite, anxiety, tremor, addiction and disturbance of normal sleep patterns

124
Q

Which part of the brain synthesises melatonin?

A

Pineal gland

125
Q

Does exogenous (externally produced) melatonin improve sleep?

A

Exogenous melatonin has a slight, but statistically significant, soporific (sleep-promoting) effect

126
Q

A substance that adjusts the timing of internal biological rhythms are called what?

A

Chronobiotic

127
Q

What are the two complementary categories of sleep disorders?

A

Insomnia and hypersomnia

128
Q

True or False:

Many cases of insomnia are caused by physicians

A

True

129
Q

What are the two types of sleep apnea disorders?

A

Obstructive sleep apnea

Central sleep apnea

130
Q

What is obstructive sleep apnea?

A

Sleep apnea caused by muscles spasms or atonia (lack of muscle tone) that block respiratory passages

131
Q

What is central sleep apnea?

A

The failure of the CNS to stimulate respiration

132
Q

What are the symptoms of narcolepsy?

A

Severe daytime sleepiness and repeated, brief daytime sleep episodes
Cataplexy
Sleep paralysiss
Hypnagogic hallucinations

133
Q

What findings have suggested that narcolepsy is caused by an abnormality in the mechanisms that trigger REM sleep?

A

People with narcolepsy often go straight into REM sleep when they fall asleep
They experience dreamlike states and loss of muscle tone while awake

134
Q

Which neuropeptide is responsible for narcolepsy?

A

Decreased orexin

135
Q

Which part of the brain produces orexin?

A

Posterior hypothalamus

136
Q

Individuals who experience REM sleep without core muscle atonia suffer from what?

A

REM-sleep behaviour disorder

137
Q

Which part of the brain is responsible for core muscle atonia during REM sleep?

A

Nucleus magnocellularis

138
Q

True or False:

There is no differences between individuals who sleep 6 hours or less and individuals who sleep 8 hours or more

A

True

139
Q
Because REM sleep is similar to wakefulness in several respects, it makes sense that REM sleep circuits are controlled by a structure involved in maintaining wakefulness:
Select one:
a. the reticular activating system.
b. the basal forebrain.
c. the thalamus.
A

a. the reticular activating system.

140
Q
Bilateral lesions of the \_\_\_\_\_\_\_\_\_\_ selectively disrupt circadian cycles.
Select one:
a. reticular activating system
b. suprachiasmatic nuclei
c. lateral hypothalamus
d. lateral preoptic area
A

b. suprachiasmatic nuclei

141
Q
During REM sleep, changes in autonomic nervous system activity suggest:
Select one:
a. neural inactivity.
b. increased relaxation.
c. unresponsiveness.
d. arousal.
A

d. arousal.

142
Q
Melatonin is synthesized from:
Select one:
a. GABA.
b. glutamate.
c. serotonin.
d. dopamine.
A

c. serotonin.

143
Q
Most selective sleep-deprivation studies have been studies of \_\_\_\_\_\_\_\_\_\_ deprivation.
Select one:
a. REM-sleep
b. stage 3 sleep
c. NREM-sleep
d. stage 2 sleep
A

a. REM-sleep

144
Q
Paradoxically, insomnia is often caused by:
Select one:
a. hypnotic drugs.
b. anxiety.
c. depression.
d. Sleep deprivation.
A

a. hypnotic drugs.

145
Q
REM sleep without the usual core muscle atonia is likely a consequence of damage to the:
Select one:
a. caudal hypothalamus.
b. nucleus magnocellularis.
c. subfornical organ.
A

b. nucleus magnocellularis.

146
Q
Slow-wave sleep seems to play a particularly important
Select one:
a. physiological role.
b. psychological role.
c. circadian role.
d. recuperative role.
A

d. recuperative role.

147
Q
Theories postulating that sleep permits the body to recover from internal deficits produced by wakefulness are often referred to as:
Select one:
a. recuperation theories.
b. free-running theories.
c. circadian theories.
d. adaptation theories.
A

a. recuperation theories.

148
Q

Under normal living conditions, most people sleep during:
Select one:
a. the rising phase of the circadian body-temperature cycle.
b. body temperature homeostasis.
c. internal desynchronization.
d. the falling phase of the circadian body-temperature cycle.

A

d. the falling phase of the circadian body-temperature cycle.