Chapter 9 Flashcards
Richter (1922) and others
The body generates its own cycles of activity and inactivity
rhythm that prepares animal for seasonal changes
endogenous circannual rhythm
rhythms that last about a day
endogenous circadian rhythms
Behaviors subject to circadian rhythms:
waking & sleeping eating & drinking urination secretion of hormones sensitivity to drugs others (e.g., body temp)
rhythm that occurs when no stimuli reset or alter it
free-running rhythm
effect of staying up all night
feel sleepier and sleepier as the night goes on; as sun comes up become more alert
the stimulus that resets the circadian rhythm
zeitgeber
Dominant zeitgeber for land animals
light
other zeitgebers
exercise, noise, meals, temp. of environment
Going east to west
we Phase-delay our circadian rhythms
going west to east
we phase-advance our rhythms
a disruption of circadian rhythms due to crossing time zones
jet lag
ppl who sleep irregularly
shift work
stress elevates adrenal hormone ____
cortisol
effects of cortisol
damages neurons in the hippocampus
part of the hypothalamus (basic body functions); provides the main control of the circadian rhythms for sleep and body temperature
Suprachasmatic nucleus (SCN)
damage to the SCN
less consistent body rhythms that are no longer synchronized to environmental patterns of light and dark
cells have their own photopigment
melanospin
2 types of genes are responsible for generating the circadian rhythm
period and timeless
produce proteins called PER
period
produce proteins called TIM
timeless
An endocrine gland located posterior to the thalamus
pineal gland
influences both circadian and circannual rhythm
melatonin
is a state that the brain actively produces
sleep
o Characterized by a moderate decrease in brain activity and decreased response to stimuli
sleep
extended period of unconsciousness characterized by low brain activity that remains fairly steady
coma
person alternates between periods of sleep and moderate arousal but no awareness of surrounding
vegetative state
person shows little response to stimuli
coma
some autonomic arousal to painful stimulus, but no purposeful activity or response to speech
veg. state
one stage higher than a veg. state marked by occasional brief periods of purposeful action and limited speech comprehension
minimally conscious state
brain dead; no sign of brain activity and no response to any stimulus
brain death
impaired ability to breathe while sleeping
sleep apnea
condition characterized by frequent periods of sleepiness during day
narcolepsy
characterized by repeated involuntary movement of the legs and sometimes the arms
periodic limb movement disorder
ppl w/this disorder move around vigorously during REM periods, apparently acting out their dreams
REM behavior disorder
experiences of intense anxiety from which a person awakens screaming in terror
night terrors
Common and harmless
sleep talking
runs in families and occurs mostly in children
sleepwalking
analogous condition is sleep sex; ppl engage in sexual behavior during a sleeplike state and don’t remember it afterward
sexsomnia
as close to being dead w/o actually being dead
brain death
records average of the electrical potentials of the cells and fibers in the brain areas nearest each electrode on the scalp
electroencophalograph (EEG)
a combo of EEG and eye-movement records
polysomnograph
have frequency of 8 to 12 per sec.
alpha waves
have characteristics of relaxation, not of all wakefulness; present when one begins a state of relaxation
alpha waves
EEG is dominated by irregular, jagged, low-voltage waves
stage 1 sleep
sleep has just begun; brain activity begins to decline
stage 1 sleep
characterized by sleep spindles and k-complexes
stage 2 sleep
result from oscillating interactions between cells in the thalamus and the cortex
sleep spindle
12 to 14-Hz waves during a burst that lasts at least half a second
sleep spindle
a sharp high amplitude negative wave followed by a smaller, slower positive wave
k-complex
stages 3 and 4 constitue
slow wave sleep (SWS)
more than half the record includes lrg waves of at least .5 second duration
by stage 4
EEG recording of slow, lrg amplitude wave, highly synchronized neuronal activity, slowing of heart rate, breathing rate, and brain activity
stages 3 and 4 (SWS)
discovered and named paradoxical sleep
jouvet
periods of rapid eye movement during sleep
REM sleep
REM
rapid eye movement
deep sleep in some ways, but light sleep in other ways
paradoxical sleep
synonymous to REM
paradoxical sleep
EEG shows irregular, low voltage fast waves that indicate increased neuronal activity. however, postural muscles of body are more relaxed than in other stages
REM sleep
stages other than REM are known as
non-REM (NREM) sleep
each cycle lasts approximately
90 minutes
part of reticular formation that contributes to cortical arousal
pontomesencephalon
small structure in the pons that emits bursts of impulses in response to meaningful events, especially those that produce emotional arousal
locus coeruleus
neurotransmitter released by pathway from hypothalamic-axons releasing orexin extend to basal forebrain and other areas and stimulate neurons responsible for wakefulness
hypoctretin OR orexin
necessary for staying awake
orexin
other pathways from lateral hypothalamus regulate cells in ______
basal forebrain
provide axons that extend throughout thalamus and cerebral cortex- some release acetyocholine
basal forebrain cells
High amplitude electrical potentials
PGO waves
During REM sleep:
activity increases in pons & limbic system.
activity decreases in primary visual cortex, motor cortex, & dorsolateral prefrontal cortex, but increases in parts of parietal & temporal cortex.
REM sleep associated w/PGO waves.
REM sleep depends on relationship between _________
serotonin & acetylcholine
AKA inadequate sleep
insomnia
the best gauge of insomnia is how one feels the next day
insomnia
causes of insomnia
stress, noise, pain, diet, uncomfortable temps, medications.
Epilepsy, Parkinson’s disease, brain tumors, depression, anxiety, or other disorders.
some cases relate to shifts in circadian rhythms.
has trouble falling asleep at usual time
rhythm is phase-delayed
falls asleep easily but awakens early
rhythm is phase-advanced
Causes of sleep apnea
genetics, hormones, old-age deterioration of the brain mechanisms that regulate breathing, obesity
4 main symptoms of narcolepsy
gradual or sudden attacks of sleepiness during the day.
occasional cataplexy.
sleep paralysis.
hypnagogic hallucinations.
attack of muscle weakness while person remains awake
cataplexy
inability to move while falling asleep or waking up
sleep paralysis
Why do we sleep; do you sleep b/c you get tired?
- You feel tired at end of the day because inhibitory processes in your brain force you to become less aroused and less alert.
People deprived of sleep
have trouble concentrating and become more vulnerable to illness
All species sleep- what benefit of sleep applies to all species?
HYPOTHESIS: sleep’s original function was to save energy
Function of hibernation
to conserve energy while food is scarce
Role of GABA in sleep
decreasing the temp and metabolic rate; decreasing the stimulation of neurons
why do we remain unconscious when we sleep?
- When a neuron is active the increased GABA lvls cut the activity short and prevent axons from spreading stimulation to other areas; when stimulation doesn’t spread you don’t become conscious of it
Emotional system
limbic system
consequences of Sleep apnea
sleepiness during the day, impaired attention, depression, and sometimes heart problems
Hypnagogic hallucinations
dreamlike experiences
what happens when most of he brain wakes up while the pons remain in REM?
the result is your experience of being temporarily unable to move
- What about using tranquilizers as sleeping pills?
o Help ppl fall asleep, repeated use causes dependence and an inability to sleep w/o the pills
Functions of sleep:
energy conservation, restoration of the brain and body, memory consolidation
- A dream represents the brain’s effort to make sense of sparse and distorted information
The activation-synthesis hypothesis
Derived from clinical studies of brain-damaged patients
The clinico-anatomical hypothesis
