Chapter 13: Why We Sleep and Dream Flashcards
a natural rhythm or cyclic changes in behaviour/bodily process
biorhythm
the time required to complete one cycle of activity
period
biorhythms are defined by their ___
periods
circannual rhythms have a period of about ___ (e.g., migratory cycles of birds)
1 year
___ have monthly or seasonal periods greater than a day but less than a year
infradian rhythms
example of an infradian rhythm
human menstrual cycle (28 days)
the menstrual cycle is linked to the cycle of the moon so is also referred to as a ___
circalunar cycle
___ have a daily period, (e.g., human sleep-wake cycle)
circadian rhythms
___ have a period of less than a day (e.g., human eating cycles)
ultradian
___ help living things adapt to the cyclical changes that take place in the environment as a result of Earth’s rotation & orbit in relation to the sun
biorhythms
the ___ incline slightly towards the sun for part of the year and slightly away from it for the rest of the year due to ___
North & South Poles; the Earth’s axis tilting slightly
the magnitude of day-night changes increases as ___ increases
distance from the equator
___ determines seasons
the tilt of Earth on its axis
day and night result from ___
rotation of Earth on its axis every 24h
migration requires adaptation to changes in:
- length of day & night
- climate
- food availability
almost every living organism & every living cell displays ___
circadian rhythms
___ change colour in a rhythmic pattern
lizards & crabs
the existence of a biological clock was first recognized in 1729 by geologist ___
Jean Jacques d’Ortous de Mairan
Jean Jacques d’Ortous de Mairan’s conclusion about plant movement
movement of the plant is endogenous, it is caused by an internal clock that matches the temporal passage of a real day
a circadian clock regulates ___ as appropriate to day-night cycles; they also produce ___ effects
feeding/sleeping times & metabolic activity; epigenetic
detailed study of biorhythms had to await the development of ___
electrical & computer-based timing devices
rat behaviour was first measured by ___
giving the animal access to a running wheel for exercise
animals adjust their circadian activities in response to:
- availability of food
- presence of predators
- competition within their own species
to determine whether a rhythm is produced by a biological clock, researchers can conduct tests in which they manipulate these conditions:
- continuous light
- light of varying brightness
- continuous darkness
- light choice of the participant
- eating, activity, sleep times all regulated
who first demonstrated that the human sleep-waking rhythm is governed by a biological clock that has a preferred period, where people selected the length of their own day & night?
Aschoff
during Aschoff’s experiment, the period of the participants’ sleep-wake cycles lengthened to about ___
25-27hrs
rhythm of the body’s own devising in the absence of all external cues
free-running rhythm
when light, eating times, temperature, and sleep times are added into an experiment to more closely regulate behaviour, the avg human free-running period is about ___
24.1-24.2hrs
the period of free-running rhythms also depends on the ___ of a species
light-related biology
environmental event that entrains biological rhythms; German for “time giver”
Zeitgeber
___ is the most potent Zeitgeber for many animals, including humans
light
to determine or modify the period of a biorhythm
entrain
when a Zeitgeber resets a biorhythm, the rhythm is said to be ___
entrained
nonphotic Zeitgebers
- temperature
- activity
- mealtimes
- work
- social events
seasonal affective disorder (SAD) affects ___ of ppl who live in northern latitudes
10%
whose findings support an association between altered circadian rhythms & depression?
Zhang
because a class of retinal ganglion cells that express a photosensitive pigment called melanopsin are responsive to blue light, it has been proposed that exposure to bright white light that contains this blue frequency can ___
reset the circadian clock & ameliorate depression
in ___, the idea is to increase the short winter photoperiod by exposing a person to artificial bright light in the morning or both morning & evening
phototherapy
exposure to artificial light that changes activity patterns and so disrupts circadian rhythms
light pollution
light pollution has increased w/ the use of ___, in which blue wavelengths are not filtered
LED (light-emitting diode) lights
___ account for inconsistent behaviour associated w/ accidents, daytime fatigue, alterations in emotional states, obesity, diabetes, & other disorders characteristic of metabolic syndrome
disruptions of the circadian rhythm
adapting to night shifts are difficult & stressful, and increases ___ by ___
susceptibility to disease; altering immune system rhythms
people who work night shifts & switch between work/nonwork schedules have higher incidence of ___
metabolic syndrome
the difference between a person’s circadian rhythm & the daylight cycle in a new environment can produce ___
the disorientation & fatigue of jet lag
fatigue & disorientation resulting from rapid travel thru time zones & exposure to a changed light-dark cycle
jet lag
travelling ___ is generally more difficult than east-to-west
west-to-east
the ___ biological clock resets in a day, and ___ follow after about a week
brain’s; other body organs
persistent asynchronous rhythms generated by jet lag are associated w/ ___
- altered sleep & temperature rhythms
- fatigue
- stress
- reduced success (sports)
who was the first researcher who attempted to locate biological clocks in the brain?
Curt Richter
Curt Richter tested wild rats in activity wheels & found that they lost their circadian rhythm after damage to the ___
hypothalamus
the ___ acts as the master biological clock, located just above the ___ where the optic tracts cross at the base of the hypothalamus
suprachiasmatic nucleus (SCN); optic chiasm
evidence for the SCN’s role as a CNS biological clock comes from:
- loss of physical eating, drinking, exercise after brain damage
- activity of SCN cells during light phases of cycle
- presence of a pathway from the eye to SCN
evidence for the SCN’s role as a CNS biological clock comes from:
- loss of physical eating, drinking, exercise after brain damage
- activity of SCN cells during light phases of cycle
- presence of a pathway from the eye to SCN
although the SCN is considered the brain’s master clock, these 2 structures also have a clocklike role in controlling behaviour
- intergeniculate leaflet
- pineal gland
animals without an SCN can still display ___ and can ___
anticipatory behaviour (becoming active in relation to scheduled mealtimes); organize related behaviours, incl. memory for food locations, in relationship to mealtimes
___ can act as a Zeitgeber for the main SCN clock
scheduled feeding activity
___ is a property of SCN cells
rhythmic activity
the SCN receives info about light thru the ___
retinohypothalamic tract
the main source of the retinohypothalamic tract signal comes from ___ that contain the photosensitive pigment ___, which is sensitive to ___ light
specialized retinal ganglion cells (RGCs); melanopsin; blue
4 steps of the retinohypothalamic tract
- SCN drives oscillators + receives signals from other brain/body areas
- signal from SCN core neurons entrains shell neurons
- retinohypothalamic tract carries info about light changes to core cells in the SCN
- photosensitive retinal ganglion cells respond to blue light
melanopsin-containing RGCs also receive inputs from ___
cones + rods
one solution to unwanted blue-light stimulation
filter out blue light using filters that give light a yellow appearance
melanopsin-containing photosensitive RGCs are distributed across the ___, and in humans they make up between ___ of all RCGs - their axons innervate the SCN ___
retina; 1-3%; bilaterally
melanopsin-containing ganglion cells use ___ as their primary neurotransmitter but contain 2 cotransmitters: ___ and ___
glutamate; substance P; pituitary adenylate cyclase-activating polypeptide (PACAP)
when stimulated by light, melanopsin-containing RGCs are excited, and in turn excite cells in the ___
SCN
the SCN contains two parts: a ventrally located ___ that’s activated by the retinohypothalamic tract, and a dorsally located ___
core; shell
in the SCN, ___ neurons are not rhythmic, but they entrail the ___ neurons, which are rhythmic
core; shell
in addition to receiving retinohypothalamic input, the SCN receives projections from other regions like ___
- intergeniculate leaflet (thalamus)
- raphe nucleus (serotonergic)
the ___ are pathways thru which nonphotic events can influence the SCN rhythm, such as by arousal, moving about, or feeding
intergeniculate leaflet + raphe nucleus
evidence supporting the idea that suprachiasmatic cells are genetically programmed for rhythmicity comes from studies performed in Canada by ___ with the use of ___
Martin Ralph; transplantation techniques
rhythms of many, but not all, body organs show restored rhythmic activity following ___
suprachiasmatic transplant
two proteins combined into one
dimer
a cell’s main clock mechanism is a ___ that paces the clock over a 24h period
transcription-translation-inhibition-feedback loop
how does the SCN control biological rhythms?
- light info from photosensitive RGCs entrains the suprachiasmatic nucleus pacemaker
- pacemaker has a rhythm that drives slave oscillators, which control functions that exhibit circadian activity
the multiple pathways the SCNclock entrains slave oscillators thru
- send axonal connections to nuclei in the hypothalamus + thalamus
- connects w/ pituitary endocrine neurons
- sends indirect messages to autonomic neurons in spinal cord to inhibit pineal gland from producing melatonin
the SCN controls these 2 hormones:
- melatonin
- glucocorticoids
the SCN controls the release of ___ from the pineal gland so it circulates during the dark phase of the circadian cycle
melatonin
the SCN controls the release of ___ from the adrenal glands so they circulate during the light phase of the circadian cycle
glucocorticoids
___ promotes sleep & activates the parasympathetic rest-and-digest system
melatonin
___ mobilize glucose for cellular activity to support arousal responses in the sympathetic system
glucocorticoids
example of the SCN controlling circannual rhythms
hamsters are summertime (long-day) breeders
- as days lengthen, gonads of male hamsters grow & release hormones that stimulate sexual behaviour
melatonin’s effect on reproductive behaviour in ___ is the reverse of the hamster: reproductive activities begin as melatonin release ___
sheep & deer; increases
there is no evidence that a melatonin cycle influences the gonads of ___
human males
who hypothesized in their book “Biological Clocks in Medicine and Psychiatry” that many physical/behavioural disorders might be caused by an upset in the timing of biological clocks?
Curt Richter
the attacks of mental illness displayed by English writer ___ appear to have a cyclic component
Mary Lamb
time type; individual variations in circadian activity
chronotypes
“lark” & “owl” chronotypes are likely produced by differences in ___ and ___
SCN neurons; the genes that influence the clock in those neurons
in hamsters & mice, mutant gene variations produce chronotypes w/ circadian periods as varied as ___
24, 20 or 17 hrs
small changes in about __ genes influence the chronotypes that African Americans have shorter ___ than European Americans, due to ancestors living closer to the equator
10; free-running periods
circadian rhythms can influence:
- emotional experience
- learning & retention
- decision making
- motivation
we now understand that chronotype changes with ___: many people shift from being ___ owls to being ___ larks
age; adolescent; old
Gale and Martyn tested Benjamin Franklin’s maxim ___, and found that neither group was any healthier, wealthier, or wiser than the other
“early to bed and early to rise to make a man healthy, wealthy and wise”
Schmidt’s conclusions about performance & time of day:
- synchrony between time of day & chronotype is a dominant effect (morning people thrive in the morning, vice versa)
- highly practiced behaviours are not influenced by time-of-day effects
- large differences between old/young ppl related to performance & time of day or related to chronotype
- a weakness of studies is that they rely on self-reports of chronotype
“is memory for learned items better when test-restest is given at the same time of the circadian cycle?” refers to ___
time stamping
as animals ___ their ability to associate appropriate activity w/ appropriate time declines, impairing their ___
age; daily schedule
a strong home advantage in sports likely stems from a ___
time-of-day effect
who found heightened emotional responses to stimuli at night, supporting the notion that circadian period influences emotional behaviours?
Li
who proposed that the mind must be independent of the body that undergoes sleeping & waking transitions due to lucid dreams?
Rene Descartes
contemporary fMRI studies suggest lucid dreaming is especially common in people who display high levels of prefrontal cortex activity in ___
Brodmann’s areas 9 +10
what we refer to as “waking” comprises these 3 states:
- alert consciousness w/o accompanying movement (cholinergic system activity)
- consciousness w/ movement is associated w/ additional serotonergic system activity
- the peptide orexin plays a role in maintaining waking activity
___ entails 3 stages, while ___ contains 2
N-sleep; R-sleep
when one is conscious of being awake during the atonia & visual & emotional features of a dream
cataplexy
when one experiences the hallucinations & fears that are common in dreams
sleep paralysis
what suggested that eye closure is sufficient to produce the visual components of R-sleep with neither loss of consciousness nor atonia?
- J. Allan Hobson had complete insomnia for 10 days after his stroke
- whenever he closed his eyes, he had visual hallucinations that had a dreamlike quality
what does the study of sleep tell us about consciousness?
a remarkable # of variations of conscious states exist - far more than just sleeping/waking
one measure of sleeping/waking behaviour where people record in a diary when they wake & when they retire to sleep
self-report
people sleep more when:
- they are young
- after engaging in physical activity
- they are pregnant
napping is normally best if it is:
- short in duration (less than 20min)
- happens earlier in the day
- occurs at schedules times of the day
measuring sleep requires recording at least 3 electrical body signals:
- brain activity
- muscle activity
- eye movement
electrodes pasted onto standard locations on the skull’s surface yield an ___
encephalogram (EEG)
electrodes placed on neck muscles provide an ___
electromyogram (EMG), a record of muscle activity
electrodes located near the eyes provide an ___
electrooculogram (EOG), a record of eye movements
EEGs show distinct patterns of brain-wave activity for sleep states such as:
- awake
- relaxed
- drowsy
- sleep
- deep sleep
- dreaming
sleep consists of periods when a sleeper is ___ and periods when the ___ twitch
relatively still; mouth, fingers & toes
who observed that twitching is periodic & is also associated w/ rapid eye movements (REMs) & an awake pattern in the EEG record?
Eugene Aserinsky + Nathan Kleitman
faster brain-wave pattern displayed by the neocortical EEG record during sleep
REM sleep (R-sleep)
slow-wave sleep associated w/ rhythms having slower waves + larger amplitude
non-REM (NREM) sleep (N-sleep)
the American Association of Sleep Medicine’s 5-point classification of sleep
W - waking
N1 - NREM stage 1
N2 - NREM stage 2
N3 - NREM stage 3
R - REM
waking
N1-sleep
N2-sleep
N3-sleep
R-sleep
when a person is awake, the EEG pattern consists of ___ with a ___, or beta rhythm, defined by a frequency of ___
small-amplitude waves; fast frequency; 15-30 Hz
fast brain-wave activity pattern associated w/ a waking EEG
beta rhythm
in waking state, the EMG is ___ and the EOG indicates ___
active; that the eyes move
large, extremely regular brain waves w/ a frequency ranging from 7-11 Hz; found in most ppl when relaxed w/ eyes closed
alpha waves
humans generate alpha rhythms in __, and abruptly stop if a relaxed person ___
the visual cortex at the back of the brain; is disturbed or opens their eyes
does everyone display alpha rhythms?
no
in __ sleep, EEG indicates beta-wave activity give way to low-amplitude, mixed frequency activity, including 4-7 Hz theta-wave activity; EMG remains somewhat active; EOG indicates eyes can be rolling
N1
in ___ sleep, a person continues to produce theta waves but also produces periodic sleep spindles (brief runs of 11-18 Hz rhythmic waves) + K-complexes, well-defined sharp waves followed by slow waves, all lasting for about half a second
N2
in ___ sleep, one is difficult to arouse, groggy when aroused, quick to go back to sleep when undisturbed; EEG has larger-amplitude, slow waves (delta rhythms); EMG indicates muscle activity; EOG indicates eyes do not move
N3
slow brain-wave activity pattern associated w/ deep sleep
delta rhythms
in ___, EEG displays beta rhythm similar to W/N1 stage; EMG indicates muscles are inactive (atonia); EOG indicates the mouth, fingers & toes twitch
R-sleep (REM)
reduced muscle tone; condition of maximally low muscle inactivity produced by motor neuron inhibition
atonia
measures of ___ generally decline during sleep
metabolic activity (e.g. body temp)
an N-R sequence lasts approx ___ and occurs ___ over the course of the participant’s sleep period
90 minutes; 5x
___ dominates early sleep periods while ___ dominates later sleep periods
N-sleep; R-sleep
periods of R-sleep are high in ___, increase during ___, in conjunction with ___, and during ___
infancy; growth spurts; physical exertion; pregnancy
during ___, body temp declines, heart rate + blood flow decrease, body weight decreases from perspiration, growth hormone levels increase; also when we toss/turn
N-sleep
___ is a disorder in which ppl experience unpleasant sensations in the legs (creeping, crawling, tingling, pulling) often accompanied by periodic leg movements
restless leg syndrome (RLS)
RLS affects ___ of the population, and more commonly ___
5%; women
2 explanations for the twitching of eyes, face & distal parts of limbs in R-sleep
- such movements help maintain blood flow
- brain is developing coordinated movements/tuning the neural circuits
who discovered that vivid dreaming occurs during R-sleep in 1957?
William Dement + Nathaniel Kleitman
research shows that dreams take place in ___
real time
why does it appear that a dream takes place in a moment?
time shrinking is a product of remembering a dream (just like recalling other memories)
the first modern treatment of dreams was made by ___ in “The Interpretation of Dreams”, published in 1900
Sigmund Freud
Freud suggested the function of dreams is the ___ & further proposed that dreams have 2 levels of meaning, ___ and ___
symbolic fulfillment of unconscious (sexual) wishes; manifest content (bizarre); latent content (true)
Freud pointed out that a dream usually begins with an ___, incorporates ___, & includes ___
incident from the previous day; childhood experiences; ongoing unfulfilled wishes
who proposed that dream symbolism signifies distant human memories long since lost to conscious awareness?
Carl Jung
Carl Jung proposed that dreams allow the dreamer to ___
relive the history of the human race - our “collective unconscious”
J. Allan Hobson’s activation-synthesis theory
- during a dream, the cortex is bombarded by signals from the brainstem
- produces the pattern of waking EEG
- in response, cortex generates images, actions & emotions from personal memory stores
- in absence of external verification, these dream events are fragmented/bizarre
- only reveals that the cortex is activates
Hobson proposed, on the bases of PET imaging, that part of the frontal cortex is ___ active in dreaming than waking
less
in Hobson’s theory, dreams are personal in that ___, but have no intrinsic meaning
memories & experiences are activated
who uses content analysis to argue that dreams are biologically adaptive in that they lead to enhanced coping strategies for threatening life events?
Anttio Revonsuo
what was Revonsuo’s justification about dreams providing strategies for dealing with problems specifically?
noted people seldom dream about reading, writing & calculating, even if that fills up their day
who suggests that reward-seeking behaviour is as likely to represent a dream’s latent content as avoidance behaviour?
Malcolm-Smith
do dreams occur in N-sleep?
yes
when one is aware of their dream as they are dreaming
lucid dreaming
who argues that daydreams are ordinary & often fun, w/ little of the turmoil of REM dreams, and seem the true opposite of night dreams?
Eric Klinger
very young children spend a lot of time in R-sleep yet do not report ___ dreams filled with ___
complex; emotion/conflict
children may experience brief frightening dreams called ___ during N-sleep
night terrors
findings from sensory deprivation research reveal that when participants are isolated in quiet bedrooms, they spend ___ time asleep
less
3 contemporary explanations for sleep
- adaptive
- restorative
- supportive of memory
___ have a long awake time and short sleep time, while ___ sleep the most as they consume most of their food at a single meal
prey; predators
(ascending) avg time animals spent sleeping per day
donkey
human
guinea pig
rat
rabbit
cat
opossum
herbivores sleep ___ than carnivores
less
switching off the ___ during sleep (esp. N-sleep) conserves energy
brain
recurring cycle of temporal packets (about 90min periods in humans), during which an animal’s level of arousal waxes & wanes
basic rest-activity cycle (BRAC)
who suggested that animals have a BRAC, and that it can’t be turned off?
Kleitman
one hypothesis of sleep as restorative
chemical events that provide energy to cells are reduced during waking & replenished during sleep
in 1965, ___ broke the world record of 260 hrs (11 days) of consecutive wakefulness & reported no ill effects
Randy Gardner
during his period of sleep deprivation, Gardner ___ & had ___, but these did not last afterwards
hallucinated; cognitive/memory lapses
sleep deprivation & irregular sleep are associated with poorer ___; the deficit is in maintaining ___
cognitive function; sustained attention
brief sleep period lasting a second or so
microsleep
2 effects of R-sleep deprivation
- increased tendency to enter R-sleep in subsequent sleep sessions
- experience R-sleep rebound, showing more than the usual amt of R-sleep in the first available sleep session
some evidence suggests that R-sleep deprivation ___
weakens the immune system, decreasing resistance to infections + other disease
rodent studies suggest R-sleep deprivation reduces ___, esp in the ___, thus ___
neurogenesis; hippocampus; impairing memory processes & weakening resistance to stress
argument against effects of prolonged/complete R-sleep deprivation
- virtually all antidepressant drugs suppress R-sleep
- lower-brainstem damage = complete loss of R-sleep
___ of ppl on antidepressants display R-sleep behavioural disorder, suggesting that some aspects of R-sleep are resistant to the drug
6%
patients with ___ remained ambulatory & verbally communicative, appearing to live satisfactory without R-sleep
brainstem lesions
conscious info, autobiographical memories, knowledge of facts
episodic memory
unconscious processes, motor skills
implicit memory
the central challenge for sleep-related memory research lies in ___
associating the complexity of memory w/ the complexity of brain metabolic & genetic events
both naps & a night’s sleep are followed by improved ___
memory
memory has 3 phases:
- labile
- storage
- recall
as a memory is encoded, it is fragile & must compete w/ existing memories & the addition of new memories, associated w/ activities of walking, memory is at risk for being abolished
labile phase
forges a relatively permanent representation of the memory, depends on biochemical/genetic activities that underlie structural changes in the nervous system, which are better formed in sleep
storage phase
puts the memory to work at some future time & integrates it into existing memory stores
recall phase
propose that different kinds of memory are stored during different sleep states
multiple process theory
propose that different features of a memory are improved in different ways during different sleep states
sequential process theories
propose that brain regions that handle different kinds of memory during waking continue to do so during sleep
storage process theories
theory based on the idea that sleep allows synapses that have been active during waking to return to a relatively quiet state during sleep
synaptic homeostasis memory theory of sleep
___ is a major consumer of the brain’s energy + is high during waking activities
synaptic activity
during sleep, the slow electrical waves, especially the ___, allow synaptic activity to shift to a resting/homeostatic energy-conserving state
4-7 Hz theta waves of N1/N2-sleep
analogy for the synaptic homeostasis memory theory of sleep
cleaning up after working each day so things do not accumulate
experiments support the homeostatic by showing that:
- access to N-sleep soon after learning improves memory
- interference w/ slow-wave activity in N-sleep disrupts memory formation
hippocampal neurons maximally responsive to specific locations in the world
place cells
who found that many hippocampal cells fire when a rat is in a certain location?
Gerrard
in rats, the correlation of cell activity during N-sleep is similar to that during ___
searches for food when previously awake
who’s experiment concluded that rule learning in both motor + cognitive domains is strengthened during sleep, including R-sleep?
Pierre Maquet
who identified a variety of mutations that disrupt memory formation/plasticity + found that memory disruptions decrease after sleep (in fruit fly Drosophila)?
Dissel
who studied spatial memory formation in chicks in which memories are mainly stored in the right hemisphere?
Nelini
sleep can survive the removal of the ___
pineal gland
in ___, only 1 brain hemisphere sleeps at a time
dolphins + birds
___ recorded cortical EEG from anesthetized cats while electrically stimulating their brainstem, and found that large, slow waves of typical anesthesia are replaced by ___?
Guiseppe Moruzzi + Horace Magoun; low-voltage fast-wave beta EEG typical of waking
experiments show that a waking EEG & waking behaviour can be induced from a large neural area running thru the center of the ___
brainstem
large reticulum (mixture of cell nuclei & nerve fibres) that runs thru the centre of the brainstem; associated w/ sleep-wake behaviours & behavioural arousal
reticular activating system (RAS)
- cortex
- hypothalamus
- reticular activating system (RAS)
- peribrachial area
- medial pontine reticular formation
prolonged state of deep consciousness resembling sleep
coma
who sustained RAS damage that left her comatose after taking a minor tranquillizer & having a few drinks, later to be removed from life support after 10 years?
Karen Ann Quinlan
which 2 brainstem systems influence waking EEG?
- basal forebrain (ACh)
- median raphe (5-HT)
how does the basal forebrain influence waking EEG?
- large cholinergic cells secrete ACh onto cortical neurons
- stimulates waking beta-rhythm EEG
- alert but immobile behaviour like paying attention
how does the median raphe influence waking EEG?
- serotonin (5-HT) neuron axons project to the cortex
- they stimulate cortical cells to produce a beta EEG
- physical movement like walking
the ___ EEG is responsible for waking associated w/ being alert yet still, whereas the ___ activation is responsible for the waking EEG associated w/ movement
cholinergic; serotonergic
what happens if both the basal forebrain system & median raphe system are removed?
- can still walk but its EEG resembles a sleeping animal
- cannot learn/display intelligent behaviour
cholinergic nucleus in the dorsal brainstem having a role in R-sleep behaviour; projects to medial pontine reticular formation
peribrachial area
who selectively destroyed peribrachial cells by spraying them w/ the neurotoxin kainic acid, and found that R-sleep was dramatically reduced?
Barbara Jones
nucleus in the pons that participates in R-sleep
medial pontine reticular formation (MPRF)
the peribrachial initiates R-sleep by activating the ___
MPRF
the MPRF sends projections to excite ___, which activate the EEG recorded from the cortex
basal forebrain cholinergic neurons
the MPRF excites ___ to produce rapid eye movements & other twitches
brainstem motor nuclei
the atonia of R-sleep is produced by the ___ thru a pathway that sends input to the ___ just behind it
MPRF; subcoerulear nucleus
the subcoerulear nucleus excites the ___, which sends projections to the spinal motor neurons to inhibit them so paralysis is achieved during R-sleep
magnocellular nucleus of the medulla
who observed that cats w/ lesions in the subcoerulear nucleus act out their dreams (loss of atonia) when they enter R-sleep?
Michel Jouvet
___ of people report ongoing sleep problems, while ___ of people report occasional sleep problems
15%; 20%
as people age, the amount of people whoo report sleep problems ___
increases
symptom of a number of disorders characterized by an inability to fall asleep/stay asleep
insomnia
disorder of falling asleep at inappropriate times, or a difficulty staying awake
hypersomnia
currently the International Classification of Sleep Disorders has ___ categories of sleep disorders
6
common causes of sleep disorders
- stress
- long work hours
- irregular lifestyle
- light pollution
anxiety & depression account for ___ of insomnias
35%
although sleeping pills promote ___, they deprive the user of ___
N-sleep; R-sleep
syndrome in which patients unsuccessfully attempt to sleep by increasing their drug dosage
drug dependence insomnia
almost complete inability to sleep that contributes to death after a number of months; caused by gene mutation of PRNP gene on chromosome 20; no treatment
fatal familial insomnia
symptoms of fatal familial insomnia
- panic attacks
- paranoia
- phobias
- weight loss
- eventual dementia
causes of daytime sleepiness
- poor sleep habits
- disruptions to circadian cycle
- jet lag
J.S. often fell asleep while sitting still, these bouts consisted of brief spurts of ___ lasting ___; treated with Ritalin
N-sleep; 5-10 mins
inability to breathe during sleep, causing a sleep to wake up to breathe
sleep apnea
why is being overweight a contributor to sleep apnea?
their respiratory pathways may be constricted
sudden infant death may be caused by ____
sleep apnea
2 things that may cause sleep apnea
- central sleep apnea: weak neural command to the respiratory muscles
- obstructive sleep apnea: collapse/blockage of upper airway
a person w/ sleep apnea can breathe as little as __ in a 6-minute period, while a healthy sleeper breathes more than 60x
4x
obstructive sleep apnea is more common among ___
overweight people + snorers
treatments for sleep apnea
- weight loss
- face mask delivering negative pressure to open airway
- appliance to expand upper airway
- surgery
untreated sleep apnea can lead to:
- high blood pressure
- cardiovascular disease
- memory problems
- weight gain
- impotence
- headaches
- brain damage due to oxygen insufficiency
rare condition in which the sufferer has recurring bouts of excessive sleeping
sleeping beauty syndrome (Kleine-Levin syndrome)
those with sleeping beauty syndrome may experience
- 15+ hr sleep episodes
- excessive sleep periods longer than 1 week
- increased urge to eat
- hypersexuality
rare condition w/ symptoms that can include sleep paralysis & cataplexy
narcolepsy
symptoms of narcolepsy include ___, and their sleep immediately starts with ___
mental cloudiness, lack of energy/concentration, memory lapses, depressed mood, extreme exhaustion; R-sleep
atonia & dreaming that occur when a person is awake, usually just falling asleep or waking up
sleep paralysis
almost ___ of students report experiencing sleep paralysis, where atonia is typically accompanied by ___
1/3; dread or fear
in sleep paralysis, the person is partially in ___
R-sleep
state of atonia, as in R-sleep, occurring while a person is awake & active; linked to strong emotional stimulation
cataplexy
if someone quickly loses muscles tone & falls to the floor after being excited or laughing, they most likely are in ___
cataplexy
dreamlike event occurring as sleep begins or while a person is in a state of cataplexy
hypnogogic hallucinations
in 1970, ___ found that narcolepsy is transmitted as a recessive trait thru the use of dogs
William Dement
who found the cause of narcolepsy in dogs?
Jerome Siegel
what causes narcolepsy in dogs?
- neurons in subcoerulear nucleus of brainstem become inactive
- neurons in magnocellular nucleus of medulla become active during attacks of cataplexy (like R-sleep)
- neuronal loss in hypothalamus + amygdala
the peptide neurotransmitter ___ serves as a signalling molecule to maintain wakefulness
orexin (hypocretin)
how do orexin cells in the hypothalamus work?
send projections similar to other brain regions in similar ways to using acetylcholine and serotonin
what confirmed that orexin loss is related to narcolepsy?
mice that lack orexin become active and collapse into cataplexy
people who display R-sleep behavioural disorder behave as though they are ___
acting out their dreams
