test 3 Flashcards
short-term homeostasis of REM sleep example
- A lengthy REM sleep episode exhausts the homeostatic drive for REM sleep, so there is time for a long NREM sleep episode before the independent drive for REM sleep again reaches threshold and initiates REM sleep again
- A short REM sleep episode does not exhaust the drive for REM sleep, so only a short NREM sleep episode can follow before the REM sleep initiation threshold is reached again
Disrupted sleep»_space;
more pain the next day in people with fibromyalgia and burn injuries
why have two regulatory mechanisms?
- Circadian clock sets the timing for sleep etc. based on the patterns that have served a species well over evolutionary time
- But circadian system can fail in unusual circumstances (e.g., inadequate food, water, or sleep)
- Homeostatic mechanisms function as an emergency backup system
homeostasis?
the mechanism by which organisms respond to spontaneous or externally induced changes in their internal environments by corrective actions that restore the initial condition
Sleep deprivation prevents the…
typical morning decline in Aβ levels in CSF
hypersomnia symptoms
- Primary complaint is daytime sleepiness where the cause is not disturbed nocturnal sleep or misaligned circadian rhythms
- Daytime sleepiness: the inability to stay alert and awake during major waking episodes of the day, resulting in unintended lapses into sleep
*not narcolepsy
hypocretin =
associated with arousal
issues comparing sleep patterns method
- EEG on animals must be done in a lab-type setting. Lab environment effects sleep parameters compared to natural environment.
- Actigraphy in natural habitat can change behaviour and effect measurements
- Cerebral mass (brain size) does not necessarily mean more neurons or increased cognitive function
disk over water: deprivation/approach/controls
- ‘total’ or stage-selective; short or very long-term (weeks)
- passive (& active); sleep onset triggers requirement to wake & walk briefly to avoid falling into shallow pool
- control animal in same environment loses much less sleep
two process model of sleep regulation?
homeostatic model of sleep regulation
sleep spindles are involved in
regulating sensory filtering and attention while awake
REM sleep deprivation leads to
increased REM sleep amounts on recovery nights
Ratities REM sleep
(diverse group of flightless, large, long-necked, and long-legged birds)
- are primitive species and show mixed REM sleep features
Reciprocal causal relationship between sleep disturbances and anxiety
-Cognitive behavioural therapy aimed at reducing insomnia symptoms given to those with cooccurring anxiety»_space; significant reductions in reported levels of anxiety
-Cognitive behaviour therapy aimed at treating anxiety symptoms in GAD»_space; reductions in reported insomnia symptoms
Observational studies have consistently found that adults with short sleep have….
higher weight
….but increasing the amount of REM sleep does not…
result in rebound decreases the following night
unihemispheric sleep
electrophysiologically defined sleep in one cerebral hemisphere while the other hemisphere remains awake
SWA is associated with
increase flow of blood and CSF into human brain
pro-inflammatory leukocytes example
interleukin (IL)-1, IL-6, IL-12, and tumour-necrosis factor (TNF)-⍺
ostrich REM sleep
- Brainstem REM sleep features (i.e., eyes closed, REM, reduced muscle tone in neck)
- Forebrain slow waves or an activated EEG
Physiological changes in rats in DOW studies observed after…
NREM and REM sleep deprivation (although more slowly with REM sleep deprivation)
Daily rhythm with increasing levels of Aβ in the CSF during….
daytime waking and lowest levels immediately after a night’s sleep
rats results?
not consistent, could be affected by strain or methods used
association between poor regulation of glucose and delayed chronotype/increased social jetlag also supported by
PSG and actigraphy studies — not just self report
paradoxical insomnia symptoms
Occurs in <5% of insomniac patients
Sleep State Misperception
by the early 21st century, only ___ of mammals sleep studied electrophysiologically
Only 3% of mammals’ sleep studied electrophysiologically
anticatapletics
medications that inhibit serotonin or norepinephrine reuptake (e.g., antidepressants)
evidence that SWS is particularly important for regulating glucose metabolism
Disrupting SWS with noise over 3 nights»_space; increased insulin resistance proportional to the amount of SWS lost, despite normal total sleep durations
Even a single night of SWS reduction»_space; increased insulin resistance
But not reductions in REM sleep
Finish the sentence: REM sleep and endothermy seem to be linked
seem to be linked in opposite ways phylogenetically and developmentally.
what is the relationship between altricial mammals and endothermy?
complex. REM sleep and endothermy seem to be linked in opposite ways phylogenetically and developmentally.
- endothermy generate REM sleep
- however, altricial mammals which are essentially ectothermic at birth show large amounts of REM sleep that steeply declines
Sleep enhances the flow of…
CSF through deep regions of cortex by expanding the volume of the interstitial space surrounding cells
Short-term sleep loss has been shown to:
- Suppress pro-inflammatory cytokines (e.g., IL-6)
- Decrease number of natural killer cells (NK cells, -leukocytes that respond to infections and tumours)
- Increase levels of anti-inflammatory cytokines
regulating REM may appear to be…
a complex process
phocidae sleep
Only bilateral sleep
Remain submerged for long periods of time without breathing
short-term homeostasis theory proposes that
- REM sleep and NREM sleep are each regulated by independent homeostatic mechanisms within a sleep period
- REM sleep is the target of homeostatic regulation and NREM sleep “fills in” the gaps between REM sleep episodes
Short term = within a cycle
Chronic, medicated, first episode, and drug-naive people with schizophrenia show…
deficits in performance of a sensorimotor filtering task
Loss of N2 sleep and sleep spindles could impair working memory, deficits in sleep-related memory consolidation
Strong correlations between the length of the NREM-REM sleep cycle and:
Metabolic rate (-0.82)
Brain weight (+0.89)
Improved sleep may act on…
immune system and depression
small platform (flowerpot): deprivation/approach/controls
- principally of REM sleep; short or long term
- passive; risk of falling into shallow pool after REM sleep onset
- multiple platforms permitting movement but not sleep, or large platforms permitting sleep
randy gardner
Deprived himself of sleep for 11 days (264 hours), lost roughly ~74 hours of usual sleep time
people who never sleep or sleep very little…
Most accounts are anecdotal with no objective evidence
sleep apnea treatment
CPAP machine that forces air through airways although that may disrupt sleep
Studies show treatments aimed at treating depression were more effective when combined with ….
CBT for insomnia
blood pressure appears to be under…
circadian control and further reinforced by sleeping
Abnormal glucose regulation reflects…
inadequate responses to the effects of insulin
anti-inflammatory leukocytes example
IL-4, IL-10, IL-13
sleep terrors usually occur during
Usually occur during transitions between N3 or N4 sleep and wakefulness
Episodes typically last a few minutes but can last up to an hour
Often occurs along with sleep walking
delta waves Hz and V
delta waves: 1-4 or 4.5 Hz, amplitude of 75-140V
Rise and fall of SWA during sleep periods in both panels
> > homeostatic mechanisms within a sleep period (i.e., drive to produce SWA gradually decreased)
bird species uni vs. bi sleep seems to be
modulated by the threat of predation
depression and sleep
-Most people with major depression find substantial changes in sleep
-Earlier onset of REM sleep in someone with depression
-Higher percentage of REM sleep relative to total sleep time in people with depression
-Seeing a lot more arousals
-Waking up really early
-Very disturbed sleep
-Large reduction in SWS
insomnia treatments
Stimulus control therapy - idea that you form associations between being in bed and sleeping. If you form an association between being in bed and not sleeping, that needs to be counter-conditioned
Sleep restriction
Relaxation
Cognitive therapies
Paradoxical intention
Sleep hygiene education
Behavioural intervention
Medication
Benzodiazepines
Melatonin agonists
Antidepressants
Antihistamines
carnivores
less vulnerable to predation. Eat energy-rich foods, can afford to sleep and conserve energy for many hours of the day (12-15 hours total)
as the day goes on, the drive for ____ increases
SWS
metabolic syndrome may take…
years to develop
tamaki studied
Studied people experiencing a “first-night effect” while sleeping in a lab
hypersomnia
some people very rarely experience hypersomnia with an episode of depression, where they sleep way more than baseline
when modelled, the level of process S reflects
- the degree of physiological need for sleep
- Current degree of sleepiness
- Predicts the amount of SWA that will be generated when sleep occurs
oleksenki results
Hemisphere that was allowed to sleep freely showed no increase in sleep duration while the other hemisphere was sleep deprived
- During recovery period, there were increases in delta-wave sleep only in the sleep-deprived hemisphere
- Increase in rate at which sleep alternated between hemispheres during recovery period
- illustrates independence of sleep production and sleep need in the two hemispheres
there is a serial positive correlation for
There is a serial positive correlation, but it goes the other way. Length of NREM sleep episode is determined by length of proceeding REM episode (flipped).
- REM —> NREM
Sleep duration association with mortality complicated by:
1.Most studies rely on participants responding to surveys about sleep length, asked in different ways
2.Very few assessments (subjective or objective) obtained in most studies
3.Potential hidden confounders
Ability of birds to implement unihemispheric sleep as needed is likely facilitated by
- Strong visual decussation in the chiasm
- Few interhemispheric connections
- Strongly lateralized eye positions
NT involvement in sleep and depression
-Early onset of REM sleep in those with major depression consistent with reduced 5HT and NE activity
-Drug treatments for depression (SSRIs, SNRIs) suppress REM sleep production
-Expected because those NT oppose REM sleep and are in SSRIs
lange et al hep A results
- People were immunized against hepatitis A
- Group 1: kept awake overnight
- Group 2: slept freely
–> Group 1: blunted antibody response
large mammals retain…
heat more effectively and therefore need to sleep less.
PSG studies and pain
- Amount of SWS an important predictor of next-day pain
- Alpha activity bursts during SWS associated with increased pain reports by people with fibromyalgia
- SWS is very important
rats, no rats survived more than
32 days
paradoxical insomni
complain little or no sleep most nights, but without objective sleep disturbances and no daytime impairments
Otariidae are
fur seals
miller study
Measured under water activity level of 59 sperm whales using data-logging tags
issues comparing sleep patterns among spcies
Most studies are correlational — otherwise you would have to alter something or change their evolution pattern
Not causation!
lange et al study topic
hep A
_____ and _____ are risk factors for vascular disease, independent of increased daytime and average 24-h blood pressure
Non-dipping and elevated nighttime blood pressure
total sleep loss in people signs
Abnormal eye movements
Inability to show visual convergence
Nausea
Abnormal sensory and reflex thresholds
Growth of lymphoid tissue in the throat
Cardiac murmur
Mood changes
Ataxia
Irritable, uncooperative
Memory lapses
Difficulty concentrating
Hallucinations
Mild astereognosis
Dysnomia
pain is usually caused by
tissue damage
tamaki results
- found increased vigilance and reduced NREM activity sleep depth only in the left hemisphere
- Presented auditory stimuli to the left and right hemispheres
- Found EEG and behavioural responses triggered at higher probability and shorter latency with stimuli presented to left hemisphere compared to right hemisphere
- Maybe localized EEG differences during sleep evolved over time
patrick and gilbert study
Kept three healthy young men awake for ~90 hours (3 ¾ days)
Depression
Major depression
Sustained negative mood
Reduced energy
Sleep problems
Loss of enjoyment of previously pleasurable activities
Insomnia
Does improving sleep improve depression?
Will help a lot with some of the symptoms, not a cure
Groups ancestral to all mammals (and birds?) may have shown only _____ during sleep (e.g., like reptiles!)
slow waves
Mechanism linking poor sleep to increased pain …?
No one mechanism, lots of things going on
schizophrenia and sleep spindles
> > Not a product of medication effects
Characteristic of early as well as chronic phases of schizophrenia (not deterioration of brain function)
why did brainstem REM sleep evolve in the first place? why did cortical desynchronization (REM) evolve later?
we dont know
homeostatic regulatory system for sleep depends critically on…
feedback (process S)
extremely short sleep is ____ and is _____
not a conscious choice; rare, genetically determined phenotype
what happens if you sleep later into the day
If you sleep later you may feel you have more dreams when you wake up
bipolar disorder – depressive episodes
- Sleep disrupted by wake episodes
- SWS reduced, REM sleep modified (earlier onset, higher density)
- More extreme sleep changes than those with unipolar depression
rem sleep and endotherms
- Remember, it is generally accepted that reptiles do not generate REM sleep
- Reptiles are ectotherms
- Is REM sleep tied to endothermy?
Elegant Crested Tinamou REM
- Brainstem REM sleep features
- Forebrain activated EEG
Non-dipping is associated with
Sleep apnea
Insomnia
Cardiac arrhythmias
Neurodegenerative diseases
sleep state misperception
ondition in which people perceive themselves to be awake for most or all of a night, even though they are objectively asleep for most of that period
by the early 21st century, only ___ of vertebrates sleep was completely assessed
0.06% of vertebrates’ sleep completely assessed
sleep disorders affect ____, some people experience disturbed sleep ___, others ______
large proportion, periodically, chronically
rheostasis?
Working together, they allow for rheostasis: The regulation of some aspect of a biological organism in a changing environment
people showing sleep state misperception also have high score for…
anxious rumination, depression, and poor coping skills
large mammals (rem)
Large mammals»_space; low metabolic rates and large brains»_space;longer NREM-REM sleep cycles
what is species adaptation related to
ecological pressures under which a species evolved
serial positive correlation direction
REM —> NREM
what about elephants vs. rabbits
- Elephants have few predators but they sleep very little, diet is quite energy poor
- Rabbits have a lot of predators and sleep a lot
smith et al study results
Group 1: pain and analgesia unaffected
Group 2: increased pain reports, impaired analgesia (feeling more pain)
Risk of developing hypertension increased with…
self-reported short sleep and insomnia complaints
insulin is released in response to
increased blood sugar following food intake
how long is an epoch
30 seconds
anti-inflammatory leukocytes are important for…
inhibiting inflammatory responses and promoting tissue healing
parasomnias are…
isorders of arousal, partial arousal, and sleep-stage transition
- Tend to occur when people are transferring through sleep stages
hatori et al study
Given access to high-fat diet all times of the day — developed fatty deposits in liver, elevated insulin levels
Given access to high-fat diet for 8h in daily dark phase
(Ate similar amounts)
Seems the circadian rhythm contributes to how glucose is processed
What happens when people develop increased insulin resistance
our cells are less sensitive to effects of insulin and not taking glucose in as easily, happens when you have had too much sugar. Your body starts to habituate to the signal and you end up with sugar left in your blood (hyperglycemia)
sleep apnea signs
Events are repeated dozens or hundreds of times a night
People may not even realize they have it — hard to know the extent to which they contribute because people often aren’t diagnosed
Monotremes (egg laying mammals) are endotherms but display
large variability in REM sleep
sleep and schizophrenia
Characterized by ‘positive’ psychotic symptoms (e.g., hallucinations, delusions) and ‘negative’ symptoms (e.g., cognitive and attentional deficits, flat affect, social withdrawal)
Studies have shown that subcortical dopamine dysfunction is a key mechanism in the pathophysiology of schizophrenia
Most studies include people currently medicated or recently withdrawn from antipsychotic medication
- Sleep features may be influenced by current or past medication
effects of total sleep deprivation: rats in the DOW procedure (over days and weeks of severe sleep loss)
Skin lesions
Severe disruption of body temperature regulation
Increased metabolic rates
Large increases in food intake
Weight loss
On second and third nights of REM sleep deprivation…
More interventions needed to prevent REM sleep early in the night
SWA could be
-art of the brain’s recovery process, or simply a reliable physiological correlate of an unidentified process
depression: effects on mediated by ___ loss, not by
SWS loss, not by reduction in total sleep time by equal amount
Fully terrestrial mammals (humans included) do not show…
unihemispheric sleep
combination of circadian and homeostatic systems allow for both
Predictive homeostasis
Reactive homeostasis
Working together, they allow for rheostasis
pain is the result of processes in…
peripheral sensory nerves, spinal cord, and the brain
Non-REM, stage 3 sleep (N3)»_space; defined as
epochs of sleep occupied by at least 20% delta waves
Chronic inflammation linked to development of
- Obesity
- Cancer
- Dementia
- Diabetes
- Vascular disease
- Depression
in studies of people limited to 3 or 4 hours of sleep per night for multiple nights, SWS amounts were…
almost completely preserved during the 3 or 4 hours of sleep permitted
promising drug treatment for depression and suicidality
Ketamine treatment for treatment-resistant depression and suicidality»_space; immediate change in glutamatergic neurotransmission»_space; increases SWS and promotes neural plasticity
These are for people who had nothing else work
pro-inflammatory leukocytes are important for…
fighting infections and disease
treatment for excessive daytime sleepiness
medications that increase the release, or inhibit the reuptake, of norepinephrine or dopamine have wake-promoting effects (e.g., Modafinil)
animals that are more primitive have…
only slow wave sleep
sleep walking tends to occur mostly during….
childhood
- Seen in 4-15% of children
- 1-2.5% of adults — tend to be quite dramatic
rats in DOW when did first rat die
after 11 days
REM sleep as a response to NREM, proposes that
- REM sleep is doing the cleaning, would expect both would be longer
- Would predict a positive serial correlation between REM and NREM
- Unfortunately, no evidence for this
Systematic reviews show mortality risk lowest for ____ nightly and increased for habitually shorter or longer sleep durations
7-8h
what is the physiological target
One or more changes in brain function that occur during extended waking and need to be reversed during recovery sleep
how long is an epoch
30 seconds
when is the best time to take drug treatments for blood pressure?
better taken at bedtime than in the morning
Physiology and anatomy of unihemispheric sleep
Acetylcholine levels are elevated bilaterally during both waking and REM sleep, but are strongly reduced during NREM sleep
Conflicting findings about responses of specific cytokines being increased in different studies in response to acute sleep loss
- Differences between sexes
- Sleep restriction for a week resulted in increased IL-6 and TNF-⍺ in men, but only IL-6 in women
the more SWS lost…
The more SWS lost, the higher the insulin resistance, despite if they had normal total sleep durations.
insulin sensitivity after chronic sleep restriction: 5hrs vs. 10hrs conditions
Very clear that healthy young men that only had 5 hours in bed a week had a much lower insulin sensitivity — struggling with blood glucose regulation after only a week
Complete sleep deprivation in humans and animals is virtually impossible
- Delay between onset of sleep episode and action by device or experimenter to wake the person/animal allow for brief sleep episodes
- Microsleeps (even with eyes open) are NREM sleep
- Isolated slow EEG waves while awake
- Increase in slower EEG activity during REM sleep periods
Bdr, SNAP-25
> > phase-advanced circadian rhythms, unstable rest-activity rhythms when housed in a light-dark cycle
Circadian organization normal under free running conditions
It’s not uncommon for one person to have…
several parasomnias
Homeostatic regulation of SWA operates both within…
a sleep period, as well as over longer time periods
bipolar disorder treatment
Most common treatment is lithium
- Reduces both mania and depression
- Reverses some sleep features (i.e., increases SWS, decreases REM sleep amounts)
large mammals =
lower metabolic rate»_space; shorter sleep durations
REM sleep in monotremes
rapid eye movements and loss of muscle tone
depression and sleep deprivation woman study 2
Seeing original high symptoms of depression, stay up all night and mood gets better. Then took a nap around 6am and symptoms went back to feeling quite depressed
Something about sleep that results in depressive symptoms increasing quite quickly again
5h being the restricted sleep condition meal patterns
eating little less for breakfast, lunch similar, dinner similar, daytime snacks similar, post dinner snacks way higher. People awake longer seem to eat way more — resulted in net weight gain over 5 days
ungulates
prey-species, vulnerable, tend to live in open areas. Tend to sleep in brief bouts and total sleep duration is very short (3-5 hours total). Because they are a prey they need to be alert. Diet is energy-poor, spend a lot of the time grazing in order to live.
differences in sleep patterns CAN be attributed to…
species’ adaptations to a specific circadian phase along with ecological factors like diet, shelter, predator-prey relations etc.
study two groups of women
4 h time in bed for 10 nights
8 h time in bed for 10 nights
- Looked at change in IL-6 (pro inflammatory cytokine — pro inflammation like a fever, trying to fight a virus — means more inflammation)
- Increased production of IL-6 in people that are sleep deprived and higher change in bodily discomfort
- Those getting less sleep have increased IL-6 and are more uncomfortable
- Potential relationship that the immune system is interacting with CNS and sleep
proportion of SWS sleep…
SWS starts heavy in the night and then decrease over time
sleep waking (somnambulism)
Person gets out of bed and engages in activities that normally occur during wakefulness
Occurs from sudden arousals from slow wave sleep (N3, N4 — SWS) (not during REM)
People sleep waking are herd to wake and do not remember the event
Tends to occur mostly during childhood
Rats chronically deprived of sleep (3-5 days of 4-6 hours of sleep, rather than their usual 10-12 hours) by means of forced walking
- Showed initial homeostatic increases in NREM sleep and/or SWA but these increases were lost over days as restriction continued
- After sleep restriction ended, showed large rebounds in REM sleep
- Rebounds in NREM sleep or SWA either did not occur or were delayed until hours later
» Allostatic processes?
insomnia symptoms
Difficulty falling asleep
Frequent awakenings
Inability to return to sleep after early morning awakening
people showing sleep state misperception may be good at _____ and poor at _____
- May be good at detecting and remembering being awake during the night
- Poor at detecting intervening sleep periods
