psych unit 4 aos 1 - sleep

sleep def

naturally and regularly occurring state of consciousness that cyclical

sleep notes

• follows internally regulated cycle

• inds in behavioural state of perceptual disengagement (less awareness sounds, smells etc) + unresponsive to envo

• psychological construct

psychological construct def

cannot be objectively measured thru data collection but widely understood to exist

consciousness

• can be described as a continuum of total to no awareness

• sleep near no awareness end

diff between normal waking consciousness (NWC) and altered states of consciousness (ASC) on the continuum

• brain wave patterns: NWC = high freq + low amp, ASC = lower freq + higher amp

• awareness levels: NWC = high, ASC = sig reduced

• perceptual abilities: NWC = all senses used to gather info and respond to stimuli, ASC = limited/absent

• time orientation: NWC = continuous and linear, ASC = distorted

brain waves amplitude

• indicates intensity/strength of brain waves → how many neurons firing tgt same time

• higher peaks + lower troughs = more synchronised brain activity e.g. during sleep

• lower peaks + higher troughs = neurons less synchronised doing diff tasks e.g. while driving

techniques to measure physiological responses during sleep

• EEG, EMG, EOG (objective)

• video monitoring (subjective)

• sleep diaries (subjective)

objective measurements of physiological responses during sleep

• most reliable measure for bod changes during various consciousness states

• EEG, EMG, EOG

• DARE = detects, amplifies, records electrical…

electroencephalograph (EEG)

DARE of the brain displayed as brain wave patterns

• brain wave patterns vary in freq and amp

frequency and amplitude

• frequency = no. brain waves per sec (speed)

• amplitude = brain waves intensity as size of peaks + troughs (height)

brain wave types

• beta waves = NWC, when alert, intense mental activity, high freq low amp

• alpha waves = we relaxed, mid-high freq (slower than beta) mid-low amp

• theta waves = light sleep/deep meditation, mid freq mid amp

• delta waves = deep sleep/unconscious, low frew high amp

— as move into deeper NREM sleep → brain waves decrease in freq and increase in amp → when move into REM → brain waves increase freq and decrease amp

electromyograph (EMG)

DARE activity of muscles

• electrodes attach to muscles → show movement, activity, tone, tension

• light sleep = muscles spasm → EMG high activity

• deep sleep = muscles relax → EMG low activity

electro-ocular graph (EOG)

DARE activity of muscles that control eye movement

• doesn’t measure eye movement !! measures movement muscles around eye

• useful for distinguishing REM and non-REM sleep

• REM sleep = EOG rec high activity

• NREM sleep = EOG rec low activity

objective measurements of physiological responses during sleep — advantages and limitations

+VES

• non-invasive

• inexpensive and safe

• objective data

-VES

• time consuming

• cannot establish activity in specific brain area

subjective data of sleep — sleep diaries

• self-reported log of ind daily sleep routine over time (usually weeks)

can record:

— qualitative data (e.g. describe dreams)

— quantitative data (e.g. 1-10 scale how refreshed after waking)

→ diary analysed by researcher → can be used alongside physiological methods → provide insight into person sleep issues

subjective data of sleep — sleep diaries advantages and disadvantages

+VES

• ind’s thoughts and feelings considered

• time-effective (?)

-VES

• results v subjective → hard to compare diff ppl

• results depend on ind reliability → needs conscious awareness and ability to describe using words

subjective data of sleep — video monitoring

• used in sleep labs to study sleep (esp sleep disturbances + disorders)

• vid cams record externally observable physiological responses e.g.

  — body position

  — breathing

  — movements like tossing, sleep walking

subjective data of sleep — video monitoring +ves and -ves

+VES =

• results can be used tgt with objective physiological measurements (can match real time in vids and observed physiological responses then to the electrical activity recorded by the machines? → more holistic understanding of ind sleep at specific time)

• observe behaviour real time

-VES =

• results can be subjective (diff ppl diff interpretations)

• reviewing vids time consuming

hypnograms

• data of person’s sleep pattern

• from left to right → stages of sleep being experienced over time

• y axis = sleep stages (with decreasing depth as goes higher)

• consider sleep cycles, amount hours in stages, ttl hours sleep, time person falls asleep/wakes, how many times awake

• each sleep cycle = U-shape

• person sleeps → N1 → N2 → N3 → back up stages → REM → repeats for 2nd cycle → third cycle onwards little time spent in N3 and more in REM → short awakenings may occur between cycles

• typical adult = 4-5 sleep cycles

2 sleep types during rest

• REM = rapid eye movement sleep

• non-REM = non-rapid eye movement sleep

1 cycle of sleep…

period of NREM sleep followed by REM sleep (usually 90 mins)

• after 1 cycle usually briefly wake

REM vs NREM sleep

• duration: REM = 25% ttl sleep, NREM = 75% ttl sleep

• brain activity: REM = very active, NREM = less active

• muscle activity: REM = muscles paralysed, NREM = muscles active

• eye movement: REM = present, NREM = not present

NREM sleep notes

• around 75% ttl sleep

• more in first half of night

• when body recuperates

• 3 stages

NREM stage 1

• light sleep = lose awareness envo

• hypnic jerk (as muscles relax we may exp spasms)

• easily woken, feel as though never slept

NREM stage 2

• regular breathing, less body movements

• still light sleep but more diff to wake up than stage 1

NREM stage 3

• deep sleep

• slow + steady breathing

• muscles fully relaxed + minimal movement

• less responsive envo

• if woken = ind groggy + disoriented

REM sleep

• rapid eyeball movement behind eyelids

• all skeletal muscles (except for breathing) paralysed

• paradoxical sleep = brain v active while body paralysed

• important for brain recovery and memory consolidation

• most dreaming here

• body paralysed so we don’t act from dreams, if woken can recall dream

how sleep cycle changes during night

early in night → more time in NREM stage 3 → as night progresses → more time in REM instead

circadian rhythm

bod changes occur as part of cycle within duration 24 hrs (to make us feel sleepy/awake certain times)

• sleep-wake cycle

• envo cues

ultradian rhythm

bod changes that occur as part of cycle within duration less than 24 hrs

• heartbeat

• respiration

• hunger

• sleep (90 min sleep cycle = one ultradian cycle)

suprachiasmatic nucleus in hypothalamus

• coordinates circadian phase (rhythm?) by regulating melatonin release in response to light

• retina detect light → transfer to SCN in hypothalamus → SCN send inhibitory (if high light) or excitatory (low light) messages to pineal gland → signal to stop (high light) or release (low light) melatonin dependent on amount light on retina

• low light = melatonin released

melatonin def

neurohormone prod in pineal gland that initiates sleepiness when its levels increase every evening

melatonin levels

• high melatonin levels = feel drowsy/tired

• low melatonin levels = feel awake/alert

— in bloodstream

— note: melatonin levels in blood monitored by SCN via negative feedback loop

what is main envo cue to influence sleep-wake cycle

light

other influences on SCN activity

• temperature: internal cue signals when to wake up and sleep (morning = SCN signals bod to wake = body temp rise = inds become alert, evening = SCN signals body sleep = body temp lowers = inds become sleepy, relaxed)

• eating and drinking patterns: SCN regulates hormone release for appetite and metabolism → when we feel hungry and when digestive sys most active (morning = SCN promotes wakefulness = ppl have regular meal times and peak metabolism, evening = SCN signals body sleep = appetite and digestion decrease)

sleep change over lifespan

as we age → amount sleep time decreases → amount REM decrease rapidly from infancy to childhood then remains stable through adulthood

LIFESPAN SLEEP CHANGES — NEWBORNS

• rec sleep hrs = 14-17

• REM:NREM = 50:50

— sleep onset anytime

— circadian rhythm not yet developed (no regular sleep-wake pattern)

— irregular sleep duration

— 50% sleep time in REM for active sleep for rapid brain development

LIFESPAN SLEEP CHANGES — CHILDREN

• rec sleep hrs = 9-11

• REM:NREM = 20:80/25:75?

— amount REM has decreased from infancy

— NREM increases esp NREM 3 as bodies growing → growth hormone release in NREM sleep

— sleepwalking, bed wetting prone

— social factors like school reduce ability to nap during day

— early bedtime, wake up early

LIFESPAN SLEEP CHANGES — ADOLESCENTS

• rec sleep hrs = 8-10

• REM:NREM = 20:80/25:75

— sleep onset delayed in evening (bc biological shift from puberty → delay melatonin release)

— prone to partial sleep deprivation (staying up late, cannot sleep in as must wake up for school)

LIFESPAN SLEEP CHANGES — ADULTS

• rec sleep hrs = 7-9

• REM:NREM = 20:80/25:75

— sleep amount decreases further from adolescence → can be according to ind

— feel tired earlier in evening and awaken earlier than adolescents

— REM:NREM proportion and sleep duration remain relatively stable during this stage

LIFESPAN SLEEP CHANGES — ELDERLY

• rec sleep hrs = 7-8

• REM:NREM = 20:80/25:75

— sig decrease NREM 3 → eventually disappears fully as body needs less recovery

— sleep becomes more fragmented → awake more during night + napping during day

explanations for sleep diffs across lifespan

• BIOLOGICAL FACTORS: changes in brain development + maturation of sleep regulatory systems → can influence sleep patterns

• HORMONAL CHANGES: shifting hormone levels like melatonin → can influence sleep patterns

• ENVO AND LIFESTYLE FACTORS: social demands, work schedules, stressors, lifestyle choices → can influence sleep patterns

changes for sleep across lifespan: exam advice → age and sleep duration

listed sleep hrs for each age group varies among diff sources → not one correct answer to hrs each group sleeps oc of variation within age grps → hence understand trends of how sleep duration changes between age grps rather than exact number of sleep hrs

sleep deprivation def

altered state of consciousness caused by inadequate quantity/quality of sleep

sleep quantity and quality

• quantity = sleep amount

• quality = how well we feel we’ve slept

— high quality sleep = makes us feel refreshed and energised

— low quality sleep = makes us feel lethargic and drowsy

partial sleep deprivation def

having some sleep in 24 hr period but less than what normally needed (quantity or quality)

partial vs total sleep deprivation

• partial = some sleep but less than what needed

• total = no sleep at all over 24 hr period or longer

partial sleep deprivation effects on…

ABC

• affective functioning

• behavioural functioning

• cognitive functioning

partial sleep deprivation effects — affective functioning

• involved with emotions

• amplified emotional responses (intense or exaggerated compared to how we’d normally react)

• easily irritated, short-tempered, moody, easily upset

• can be hard to control emotions

partial sleep deprivation effects — behavioural functioning

• involved with actions — generally observable

• slower physical reaction times

• unintended lapses into microsleep (v brief sleep period, 1-10 secs)

• reduced motor control

• more likely risky behaviours

partial sleep deprivation effects — cognitive functioning

• involved with mental processes

• difficulty concentrating (directing + maintaining attention)

• more difficulty problem solving

• memory impairment

• irrational thoughts

• difficulty doing simple repetitive tasks

dawson and reid’s research shows that…

sig relationship between fatigue from mild level sleep deprivation and legal levels of alcohol consumption on impaired performance

sleep deprivation vs BAC

• 17 hrs sleep deprivation = BAC 0.05

• 24 hrs sleep deprivation = BAC 0.10 — double the legal limit

comparative analysis sleep deprivation vs BAC

• both -vely affect functioning

— e.g. affective functioning: both can impair emotional control, more easily irritated

— e.g. cognitive functioning: both can impair attention, decision making, concentration

what can cause diffs between inds for sleep deprivation on functioning

• ind tolerance variations

• severity sleep deprivation

• severity alcohol consumption

— can all influence intensity of effects

circadian rhythm disorder

type sleep disorder where persistent pattern sleep disruption bc sig, consistent misalignment between circadian rhythm and sleep-wake schedule needed by person

• misalignment occurs → ind body cannot adjust → cause dysfunction → circadian rhythm disorder

• misalignment causes: excessive sleepiness, insomnia, impairment person functioning

• can cause ind unable sleep and wake appropriate times

— advanced, delayed, shift work

circadian rhythm disorder — delayed sleep phase syndrome (DSPS)

misalignment in timing sleep onset and awakening (compared to desired timing)

• delay usually 2 or more hours

• person fall asleep later than needed → wake up later

• who’s at risk = adolescents (puberty → body biological clock naturally delays → teens higher risk DSPS), genetic factors, light sensitivity

circadian rhythm disorder — advanced sleep phase disorder (ASPD)

advance in timing sleep onset and awakening (compared to desired timing)

• usually 2 or more hours earlier

• fall asleep earlier than needed → wake up earlier

• who’s at risk = older adults, ppl with autism spectrum disorder, genetic factors

circadian rhythm disorder — shift work

• when ppl work shifts outside 9-5 business hours → can disrupt natural circadian rhythm (esp rotational night shifts → ind body continually adapting to diff sleeping times)

• circadian rhythm cued by light → hence if need to work at night and sleep during day → then need to sleep when bright outside (lots light) and need to stay awake when dark at night → cause mismatch when they need to sleep/stay awake and tiredness levels

• can experience poor sleep quality and quantity (e.g. bc light or noise during day when they try to sleep) → hence feel tired when awake → can negatively impact ability to work

treatment of circadian phase disorders

• if ind adjust life commitments around their circadian rhythm → can exp less -ve impacts

circadian phase disorders treatment — bright light therapy

timed exposure of eyes to bright amounts light

• person exposed to special high-intensity light for set time → bright light reduce body production melatonin → make person more awake than normally would

• BLT used at time when ind needs to feel more awake/alert

bright light therapy exposure timings for diff circadian rhythm disorders

• DSPD = early morning when getting up

• ASPS = early evening

• shift work = evening before night shift

circadian rhythm sleep disorders and SCN

• DSPD = SCN don’t properly synchronise with external day-night cycle

• ASPD =SCN out of sync with external light-dark cycle

• shift work = SCN trouble adjusting to irregular sleep-wake patterns from ind’s schedule

circadian rhythm sleep disorders and eating/drinking patterns + body temp rhythm

• irregular meal timing = bc SCN influences when ppl feel hungry and when dig system most active → hence when misalignment between external cues and internal clock → irregular meal times

• temp rhythm misalignments = SCN may not signal appropriate temp changes for the sleep-wake cycle → hence hard to sleep when body temp not in optimal phase for sleep

sleep hygiene

sleep-related behaviours and envo conds that beneficial for sleep→ bedtime routine changes can improve sleep quality

zeitgebers def

envo cues that can synchronise and regulate bod circadian rhythm

— e.g. light, temp, eating patterns

— can shift ind 24 hr sleep-wake cycle → hence ind can use to improve their sleep-wake cycle → improve their mental wellbeing

zeitgeber — light

• daylight is primary zeitgeber for human circadian rhythm — includes all direct and indirect sunlight during daytime

• has greatest influence on on sleep-wake cycle bc detected by SCN → directly influence melatonin release by pg

• all light wavelengths can shift sleep-wake cycle

• blue light (prod from man-made artificial sources of light) powerful inhibition melatonin release

zeitgeber — temp

• the degree of external heat in envo that can influence quality + quantity sleep

• cool room temp → linked with improved quality + quantity sleep (bc body temp drops during sleep hence cooler room = body temp cool?)

• 18 degrees ideal

zeitgeber — eating and drinking habits

• types + quantity food and drink ind consumes can influence quality + quantity sleep

• circadian rhythm preps bod to be more efficient metabolising food during day when we active

• long-term severe food deprivation, calorie restriction, perceived starvation → all affects SCN

• alcohol, caffeine, high-sugar foods can -vely impact sleep

eating and drinking — de-synchronisation of circadian rhythm

when regularly eat and drink throughout night → can de-synchronise circadian rhythm

• risk factor for night shift workers that eat and drink at night → increase risk circadian rhythm disruption → -vely impact sleep and wellbeing

neuromodulators and the sleep-wake cycle

• dopamine and serotonin maintain alertness and motivation during waking hours → they become less active during sleep

• decrease in dopamine and serotonin activity → contributes to transition from being awake to sleep

NEUROMODULATORS AND CIRCADIAN RHYTHM SLEEP DISORDERS

• DSPS = serotonin disruptions → delayed release melatonin

• ASPD = abnormal dopamine regulation → increased alertness evening + difficulty staying awake during day

• shift work = exposure to light and work at night → affect release and sensitivity dopamine + serotonin → disrupted d + s signalling → difficulties falling asleep during day + staying awake at night

— s disruptions and abnornal d regulation → bc changes in their receptor sensitivities?