CH8 Flashcards
proposed that the body generates its own cycles of activity and inactivity
Curt Richter
Some animals generate endogenous _________, internal mechanisms that operate on an annual or yearly cycle
Example: birds migratory patterns; animals storing food for the winter
circannual rhythms
All animals produce endogenous ________, internal mechanisms that operate on an approximately 24-hour cycle
circadian rhythms
German meaning “time giver”; refers to the stimulus that resets the circadian rhythm
Examples: sunlight, tides, exercise, meals, arousal of any kind, meals, temperature of environment, and so on.
Zeitgeber
Refers to the disruption of the circadian rhythms due to crossing time zones
Stems from a mismatch of the internal circadian clock and external time
Sleepiness during the day, sleeplessness at night, and impaired concentration
Jet Lag
The main control center of the circadian rhythms of sleep and temperature
Located above the optic chiasm and part of the hypothalamus
The Suprachiasmatic Nucleus (SCN)
comes from a special population of ganglion cells that have their own photopigment called melanopsin
The retinohypothalamic path
Two types of genes are responsible for generating the circadian rhythm
Period: produce proteins called PER
Timeless: produce proteins called TIM
The pineal gland secretes ______, a hormone that increases sleepiness
Melatonin
extended period of unconsciousness characterized by low brain activity that remains fairly steady
Person shows little response to stimuli
Coma
person alternates between periods of sleep and moderate arousal but no awareness of surrounding
Some autonomic arousal to painful stimulus
No purposeful activity/response to speech
Vegetative state
one stage higher than a vegetative state marked by occasional brief periods of purposeful action and limited speech comprehension
Minimally conscious state
no sign of brain activity and no response to any stimulus
Brain death:
_____ __sleep is when sleep has just begun
The EEG is dominated by irregular, jagged, and low voltage waves
Brain activity begins to decline
Stage 1
______ sleep is characterized by the presence of:
______: 12- to 14-Hz waves during a burst that lasts at least half a second
______: a sharp wave associated with temporary inhibition of neuronal firing
Stage 2, Sleep Spindles, K-complex
______ and _______ together constitute slow wave sleep (SWS) and is characterized by:
EEG recording of slow, large amplitude wave
Slowing of heart rate, breathing rate, and brain activity
Highly synchronized neuronal activity
Stage 3, Stage 4
describes periods characterized by rapid eye movements during sleep
Also known as paradoxical sleep: deep sleep in some ways, but light sleep in other ways
is predominant later at night
is strongly associated with dreaming, but people also report dreaming in other stages of sleep
Rapid eye movement sleep (REM)
is a part of the midbrain that extends from the medulla to the forebrain and is responsible for arousal
The reticular formation
a part of the reticular formation in the midbrain, contributes to cortical arousal
The pontomesencephalon
is a small structure in the pons whose axons release norepinephrine to arouse various areas of the cortex and increase wakefulness
Usually dormant while asleep
The locus coeruleus
contains neurons that release “histamine” to produce widespread excitatory effects throughout the brain
Antihistamines produce sleepiness
The hypothalamus
The lateral and posterior nuclei of the hypothalamus releases _____
is released by cells into the basal forebrain to stimulate neurons responsible for wakefulness and arousal
orexin
Cells of the basal forebrain release the inhibitory neurotransmitter _____
GABA
A sleep disorder associated with inadequate sleep
Caused by a number of factors, including noise, stress, pain, diet, and medication
Can also be the result of disorders such as epilepsy, Parkinson’s disease, depression, anxiety or other conditions
Dependence on sleeping pills or alcohol and shifts in the circadian rhythms can also result in ______
Insomnia
A sleep disorder characterized by the inability to breathe while sleeping for a prolonged period of time
Consequences: sleepiness during the day, impaired attention, depression, and sometimes heart problems
Causes: genetics, hormones, old age, obesity and deterioration of the brain mechanisms that control breathing
Effects: cognitive impairment may result
Sleep Apnea
A sleep disorder characterized by frequent periods of sleepiness
Attacks of sleepiness during the day
Gradual or sudden attack of sleepiness
Occasional cataplexy: muscle weakness triggered by strong emotions
Sleep paralysis: inability to move while falling asleep or waking up
Hypnagogic hallucinations: dreamlike experiences
Caused by the lack of hypothalamic cells that produce and release orexin
Narcolepsy
The repeated involuntary movement of the legs and sometimes the arms while sleeping
Legs kick once every 20–30 seconds for periods of minutes to hours
Usually occurs during NREM sleep
Periodic Limb Movement Disorder
Associated with vigorous movement during REM sleep
Usually associated with acting out dreams
REM Behavior Disorder
______ are experiences of intense anxiety from which a person awakens screaming in terror
Usually occurs in NREM sleep
“_______” runs in families, mostly occurs in young children, and occurs mostly in stage 3 or 4 sleep
Not associated with dreaming
Night Terrors, Sleepwalking
Two biological theories of dreaming include
The activation-synthesis hypothesis
The neurocognitive hypothesis
Suggests that dreams begin with spontaneous activity in the pons, which activates many parts of the cortex
The Activation-Synthesis Hypothesis
Places less emphasis on the pons, PGO waves, or even REM sleep
Similar to the activation synthesis hypothesis in that dreams begin with arousing stimuli that are generated within the brain
Suggests that dreams are similar to thinking, just under unusual circumstances
The Neurocognitive Hypothesis
