Exam 3 - Sleep, dreaming, and circadian rhythms Flashcards
The 8-to-12 Hz EEG waves that are associated with relaxed wakefulness are called
A. K complexes
B. Delta waves
C. Alpha waves
D. Sleep spindles
C
During REM sleep, there
A. Is a general increase in muscle tension in the muscles of the body core
B. Is an absence of EMG activity in the muscles of the body core
C. Are occasional bursts of delta activity
D. Are occasional bursts of EMG activity from the cortex
B
Theories postulating that sleep permits the body to recover from internal deficits produced during wakefulness are often referred to as:
A. Circadian theories
B. free-running theories
C. Zeitgeber theories
D. recuperation theories
D
Species that sleep a lot tend to:
A. Be invulnerable to predation when they sleep
B. Be more active
C. Have higher body temperatures
D. Be small
A
Circadian cycles without zeitgebers are said to be:
A. free-running rhythms
B. desynchronized
C. Diurnal
D. jet lag
A
Which of the following is most likely to occur after the loss of a small amount of sleep?
A. Disruption of motor performance
B. deficits in IQ
C. Disruption of homeostasis
D. disturbances of vigilance
D
Electrical stimulation of the _________ awakens sleeping cats
A. Preoptic area
B. cerebellum
C. Reticular formation
D. basal forebrain
C
Bilateral lesions of the __________ disrupt circadian cycles.
A. Suprachiasmatic nuclei
B. lateral preoptic area
C. POAH
D. amygdala
A
What are the 3 physiological measures of sleep?
- EEG - sum of electrical activity in the brain, differentiates different stages in the sleep cycle
- Electrooculogram - eye movements seen during REM
- Electromyogram - loss of activity in neck muscles during some sleep stages
Stage 1 of sleep, what are the two components of stage 1?
- similar to awake EEG, but slower. High frequency, low voltage.
1. beta waves - mentally alert and paying attention
2. alpha waves - eyes closed, prepared to sleep
What is stage 2 of sleep characterized by?
- K complexes - large negative waves
- Sleep spindles - burst of 12-14 Hz waves
- some theta waves
What are stages of 3 and 4 of sleep characterized by?
- delta waves (large and slow)
- deeper stages of sleep
What is the order of the stages of sleep?
- initial stage 1 - stage 4
- stage 4 - emergent stage 1/stage 5 (REM)
About how long is each sleep stage?
90 minutes
REM
- rapid eye movement
- loss of core muscle tone, low-amplitude/high-frequency EEG, increased cerebral and autonomic activity, muscles may twitch
- beta waves
Slow wave sleep
Stages 3 and 4
When do vivid dreams occur? When is sleepwalking and talking less likely to occur?
during REM
What was Freud’s theory about dreaming?
dreams represent acceptable release of sexual and aggressive instincts
What is the Cognitive theory of dreaming?
dreams are a way to deal with life’s problems, and may be involved in memory storage
What is the Activation-synthesis theory of dreaming?
dreams have no inherent meaning, and result from mental interpretation of neural activity during sleep
Lucid dreaming
when you’re dreaming and aware of it
What are the theories of why we sleep? Explain each.
- Recuperation theory - sleep is needed to restore homeostasis that is deviated by wakefulness
- Circadian theory - sleep is an internal timing mechanism, and has evolved to protect us from the dangers of the night
What are free running rhythms?
rhythms that do not depend on external signals (light)
Circadian rhythms
internal timing mechanism that results in sleep, a sleep-wake cycle that lasts 24 hours
What does 3-4 hours of sleep deprivation in one night result in?
- increased sleepiness
- disturbances in mood
- decreased vigilance
What does 2-3 days of sleep deprivation result in?
- microsleeps (naps of 2-3 seconds)
What apparatus was used to deprive test-rats of sleep? What was the result of several days of sleep deprivation in these rats?
- carousel apparatus - if the rats do not awaken, they will fall into water
- death due to extreme stress
What are the two effects of REM sleep deprivation?
- proceed more rapidly into REM
- REM rebound (more time spent in REM)
What are the purposes of REM?
- necessary for mental health
- necessary for maintenance of normal levels of motivation
- necessary for processing of memories, and learning
What does damage in the posterior hypothalamus and adjacent midbrain cause?
excessive sleep
What does damage in preoptic area and adjacent forebrain cause?
wakefullness
What brain mechanism controls arousal?
- reticular activating system (begins in hindbrain and extends into midbrain)
What is the main part of the reticular activating system? What is its transmitter substance?
- locus coeruleus
- norepinephrine
What brain mechanisms control NREM sleep? What are their transmitters?
- Raphé nuclei, serotonin
- basal forebrain, GABA
What brain mechanisms control REM sleep?
decreased locus coeruleus activity removes inhibition from the caudal reticular formation, which initiates REM sleep
What CANNOT be activated if REM is to take place?
the locus coeruleus
How long are circadian rhythms?
about a day
Zeitgebers
environmental cues that entrain circadian cycles
What is the suprachiasmatic nucleus responsible for? Where is it located?
- location of the major circadian clocks
- medial hypothalamus
What does the pineal gland release? What can this be used for?
- melatonin
- shifting the circadian rhythms
Jet lag, how can it be reduced?
- zeitgebers are accelerated or decelerated, circadian rhythm is shifted
- gradually shift sleep-wake cycle
Shift work, how can it be reduced?
- zeitgebers unchanged, but sleep-wake cycle is altered
- move from current schedule to one that starts later
What is the Cerveau isole preparation?
disconnected basal forebrain from the rest of the brain
Insomnia
a long-term inability to get enough sleep
Sleep apnea
characterized by repeated interruption of sleep caused by the cessation of breathing
Sleepwalking, what type of sleep disorder is this?
- getting out of bed and walking around, occurs in stages 3 and 4
- NREM
Night terrors, what type of sleep disorder is this?
- an abrupt wakening, accompanied by intense autonomic arousal and feelings of panic, do not remember what scared them
- NREM
Bedwetting, what type of sleep disorder is this?
- characterized by a lack of bladder control during sleep
- NREM
Narcolepsy, what type of sleep disorder is this?
- sudden, uncontrollable sleep attack, usually initiated by monotonous activity
- REM
What is narcolepsy characterized by?
- fall into REM sleep randomly
1. Cataplexy - sudden, complete lack of muscle tone
2. Sleep paralysis - a brief paralysis that occurs when the individual is falling asleep or awakening
What are also a part of REM sleep?
nightmares, they do remember what scared them
About how much sleep do you need?
7-9 hours
