Module 9.2 Flashcards
What are the defining characteristics for coma?
extended period of unconsciousness caused by head trauma, stroke, or disease; low level of brain activity; little to no response to stimuli
What are the defining characteristics for vegetative state?
alternating between periods of sleep and moderate arousal; breathing is more regular; a painful stimulus produces at least the responses of increased heart rate, breathing, and sweating; no speaking, response to speech, or any purposeful activity
What is an EEG?
it records the degree of synchrony of neuronal activity; enables researchers to compare brain activity at different times during sleep
What is the behavioral correlate of alpha waves?
relaxation
What are the defining characteristics of a minimally conscious state?
occasional brief periods of purposeful actions and a limited amount of speech comprehension
What are the defining characteristics of brain death?
no sign of brain activity or response to stimuli
Describe the EEG in stage 1 sleep.
irregular, jagged, low-voltage waves
What are the EEG characteristics of Stage 2 sleep?
k-complex and sleep spindles
Which stages of sleep are classed as slow-wave sleep (SWS)?
stages 3 and 4
Why is REM sleep called paradoxical?
because it is deep sleep in some ways and light sleep in others
What is a polysomnograph?
a combination of EEG and eye-movement records
What is the typical duration of the sleep cycle?
about 90 minutes
During which part of the night is REM predominant?
towards the morning
During which parts of the night are stages 3 & 4 predominant?
earlier in the night
How good is the correlation between REM sleep and dreaming?
they usually overlap
What is the effect of a cut through the midbrain on sleep and waking cycles?
Was the result due simply to loss of sensory input or damage to a particular brains structure?
If a cut through the midbrain is made, sleep periods become longer and wake periods become more brief. Damage to a particular brain structure, reticular formation.
What is the pontomesencephalon’s relation to the reticular formation?
it is part of the reticular formation
Describe the input, output, and interconnections of the pontomesencephalon.
It receives input from many sensory systems and generates spontaneous activity. Their axons extend into the forebrain and release acetylcholine and glutamate, which excites cells in the hypothalamus, thalamus, and basal forebrain.
Give the location, neurotransmitter, and a major function of the locus coeruleus.
The locus coeruleus is located in the pons. It releases norepinehrine and it strengthens the storage of recent memories.
What is the neurotransmitter from the hypothalmus that stimulates arousal?
histamine
What is the implication of histamine for allergy treatments ?
Antihistamines, used for allergy treatments, counteract histamine and produce drowsiness.
What is the function of orexin?
helps us to stay awake
What is the major neurotransmitter released by neurons in the basal forebrain that contributes to sleep? To arousal?
GABA contributes to sleep and acetylcholine contributes to arousal.
What are PGO waves?
patterns of high-amplitude electrical potentials
Where are PGO waves recorded?
first in the pons, then in the lateral geniculate, and finally in the occipital cortex
What happens to PGO waves after a period of REM deprivation?
they begin to emerge during sleep stages 2 to 4 and during wakefullness, where they normally don’t occur
Describe the mechanism for inhibiting motor activity during REM sleep.
Cells in the pons send messages to the spinal cord, inhibiting the motor neurons that control the body’s large muscles.
Which neurotransmitter is important for REM onset?
acetylcholine
Which two neurotransmitters interrupt or shorten REM?
serotonin and norepinphrine
What is one effect of the drug carbachol?
it quickly moves a sleeper into REM sleep
How is circadian rhythm related to insomnia?
Shifts in circadian rhythm can cause insomnia.
How might sleeping pills contribute to insomnia?
dependency on sleeping pills can lead to an inability to sleep
Describe the symptoms of sleep apnea.
Waking up gasping for breath, sleepiness during the day, impaired attention, depression, and sometimes heart problems.
Which four factors contribute to sleep apnea?
genetics, hormones, old-age deterioration of the brain mechanisms that regulate breathing, and obesity
What four symptoms are commonly associated with narcolepsy?
- Gradual or sudden attacks of sleepiness during the day.
- Cataplexy: an attack of muscle weakness while the person remains awake
- Sleep paralysis: an inability to move while falling asleep or waking up
- Hypnagogic hallucinations: dreamlike experiences that the person has trouble distinguishing from reality
What tends to trigger cataplexy?
strong emotions
Explain how orexin (or lack thereof) contributes to narcolepsy.
Orexin is important for maintaining wakefulness and people with narcolepsy tend to lack the hypothalamic cells that produce and release orexin.
Describe the symptoms of periodic limb movement disorder.
Repeated involuntary movement of the legs and sometimes the arms
What are the symptoms of REM behavior disorder?
Moving around a lot during REM periods (which normal people don’t do) and acting out dreams
How do night terrors differ from nightmares?
Night terrors are scarier and more intense than nightmares
During which type of sleep are night terrors most common?
NREM
During which stages does sleep talking occur?
REM and non-REM
What stages does sleepwalking occur?
stage 3 or 4 early in the night
What is sexomnia?
when people engage in sexual behavior during a sleeplike state and do not remember it afterward
Which stages of sleep are classed as slow-wave sleep (SWS)?
stages 3 and 4
What is cataplexy?
an attack of muscle weakness while the person remains awake
What are hypnagonic hallucinations?
dreamlike experiences that the person has trouble distinguishing from reality
REM is associated with a distinctive pattern of high-amplitude electrical potentials known as __________.
PGO waves
What is a possible cause of REM behavior disorder?
damage to the cells in the pons that send messages to inhibit the spinal neurons that control large muscle movements
What is one treatment for periodic limb movement disorder?
tranquilizers
What are the characteristics of REM?
increased brain activity, decreased body movement (sleep paralysis), eye movement, facial twitches, easily awakened
