unit 4 aos 1 Flashcards
consciousness
the level of awareness an individual has to something internal or external to yourself. includes thoughts, feelings, perceptions & existence
- divided into normal waking consciousness and altered states of consciousness
what is a naturally occurring altered state of consciousness
naturally occurring in the course of our everyday activities without the need for any aid, differs in awareness from normal waking consciousness
continuum of awareness
varies from total awareness to complete lack of awareness
- total awareness
- daydreaming
- meditative state
- hypnotised
- asleep
- anaesthetised
- coma
- total lack of awareness
sleep
- a regular and naturally occurring altered state of consciousness that involves a loss of awareness and disengagement with internal and external stimuli
- cycle through NREM and REM in each sleep episode
- each cycle lasts around 90 mins, with a transition between each of the stages of NREM, and a period of REM
characteristics of NREM sleep
- replenishment of the body
- 80% of total sleep episode
- delta brain waves
- reduced physiological activity & no eye movement
- 3 stages:
- N1= light sleep, 5 mins (4-5% of cycle)
- N2 = moderate sleep, 10-25 mins, (50% of cycle)
- N3 = deep sleep, 20-40 mins (10-15% of cycle)
NREM stage 1
- light sleep
- low level of bodily arousal (HR, body temp, respiration)
- slow, minimal eye movement
- 5% of total sleep time
NREM stage 2
- moderate sleep, gradually gets deeper
- continued slowing of physiological body activity
- brain waves slow further, with brief bursts of activity
- eye movement stops
- 50% of total cycle
NREM stage 3
- deep sleep
- muscles completely relaxed
- no eye movement
- slow delta waves occurring
- less time spent in N3 as the night progresses
- 10-15% of total cycle
characteristics of REM sleep
- replenishment of mind
- beta brain waves
- 20% of total sleep episode
- spontaneous bursts of rapid eye movement, eyes move back and forth in coordinated movements
- internally active while body looks calm
- periods lengthen and occur closer together as sleep episode progresses (20-25% of cycle)
measurement of physiological responses associated with sleep
- electroencephalography (EEG)
- electromyography (EMG)
- electro-oculargraphy (EOG)
- sleep diaries
- video monitoring
electroencephalography (EEG)
- detects, amplifies and records different brain waves produced:
> beta: alert
> alpha: mentally & physically relaxed
> theta: drowsy
> delta: deep sleep - brain waves are spontaneous, rhythmic electrical impulses that come from different brain areas
electromyography (EMG)
detects, amplifies and records the electrical activity of muscles produced by sleep
electro-oculargraphy (EOG)
detects, amplifies and records electrical activity of muscles around the eyes during sleep
sleep diaries
- log used to self-record & report sleep & wake time over a period of time
- subjective data
video monitoring
record externally observable physiological responses throughout a sleep episode, including behaviours when falling asleep and waking
regulation of sleep by internal biological rhythms
changes that repeat themselves through time in a cyclical way, linked to cyclical changes in environmental cues, such as sunrise & sunset, day length, amount of light
- circadian rhythm
- ultradian rhythm
biological clock
innate timing mechanism that regulates the cycle of a biological rhythm
circadian rhythms
involves physiological, psychological or behavioural changes that occur as part of a cycle with a duration of ~24 hrs (sleep-wake cycle)
ultradian rhythms
- involves physiological, psychological or behavioural changes that occur as part of a cycle that is less than 24 hours (sleep cycle)
- heartbeat, respiration, sleep
- complete sleep cycle is ~90 mins
melatonin
- produced by the pineal gland and is involved in initiation & regulation of sleep-wake cycle
- helps feel sleepy, amount of melatonin in the blood is associated with alertness
- light determines melatonin production
- low light = produce more melatonin
- high light = produce less melatonin
suprachiasmatic nucleus (SCN)
- detects light through eyes and responds by signalling pineal gland to release melatonin
- adjusts our sleep-wake cycle accordingly by signalling pineal gland to release more or less melatonin based on how much light is detected
- initiates an increase in body temp & releasing hormones to promote alertness
- keeps sleep-wake cycle in sync with day-night cycle
age related changes in sleep
- time spent sleeping decreases as we get older, especially in the amount of N3 sleep
trends in sleep across lifespan
- infancy: ~ 16 hours a day, 50% REM, 50% NREM
- childhood: ~11-13 hrs a day, 20-25% REM, 75% NREM
- adolescence: ~9 hrs a day, 20-25% REM, 75% NREM
- adulthood: ~7-8 hrs a day, 20% REM, 80% NREM
- later adulthood: ~6 hrs
sleep restoration theory
sleep is needed to replenish the mind & bodys resources, explains why we sleep
- REM is higher when studying
- NREM is higher when exercising
sleep debt
accumulated loss of sleep from insufficient amount of sleep
sleep deprivation
a state caused by inadequate quantity or quality of sleep
- PARTIAL sleep deprivation: having less sleep than what is normally required. may occur periodically or persistently over short or long term
- TOTAL sleep deprivation: no sleep at all over a short or long term period.
effect of partial sleep deprivation on affective functioning
sleep loss interferes with emotional regulation, compromising brains ability to process emotional info & control emotions
- amplified emotional responses
- mood changes
- heightened anxiety
- depression
- irritability
- lack of motivation
effect of partial sleep deprivation on behavioural functioning
- sleep inertia: temporary period of reduced alertness & performance impairment that occurs immediately after awakening (groggy feeling)
> motor & cognitive functions are not at full capacity during sleep inertia
> sleep inertia stronger when waking during N3 than any other stage - excessive sleepiness during the day
- slower reaction times, clumsiness
- increased risk taking behaviour
- impaired control of behaviour
effect of partial sleep deprivation on cognitive functioning
- impaired attention
- impaired memory
- lack of concentration
- trouble with simple everyday tasks (driving, cooking)
- increased errors associated with loss of attention
- reduced ability to think clearly
- difficulty decision making & problem solving
- processing info in STM can be impaired
- irrational thoughts
psychological and physiological effects of sleep deprivation
physiological-
- increased HR > increased risk of heart attack
- tremors
- risk of obesity
- fatigue
- headaches
psychological-
- cognitive impairment
- memory loss
- impaired immune system
cognitive effects of one night sleep deprivation compared to BAC of 0.05 and 0.10
relationship found between fatigue due to sleep deprivation, legal levels of alcohol and impaired performance.
- cognitive effects:
> performance on cognitive tasks following 17 hrs sleep deprivation had decreased to the equivalent of a person with a BAC pf 0.05%
> performance after 24 hours sustained wakefulness was equivalent to BAC of 0.10%
- cognitive effects of moderate sleep deprivation are equivalent to or greater than the legally unacceptable amount of alcohol when driving
- lack of concentration, impaired memory, irrational thoughts, trouble decision making
affective effects of one night sleep deprivation compared to BAC of 0.05 and 0.10
- influence our emotional state
- irritable, short tempered
- can impair concentration & cognitive performance
- mood can also influence alcohol consumption
sleep disorders
persistent disturbance to the sleep-wake cycle, occur due to a problem with the timing of the sleep & wake states
- delayed sleep phase syndrome (DSPS)
- advanced sleep phase disorder (ASPD)
- shift work
delayed sleep phase syndrome (DSPS)
- the sleep episode is delayed in relation to the desired sleeping time by 2-3 hrs
- most common adolescents, affects ~7-15%
symptoms: - sleep onset insomnia
- difficulty waking
- difficulty waking at desired time
- excessive sleepiness
advanced sleep phase disorder (ASPD)
- advance of the sleep episode to an earlier time than the desired sleep time
- going to bed and waking up too early, having difficulty staying awake in the evening
- more common among older people
- onset between 6-8pm, wake between 1-3am
shift work disorder
- results from work shifts being regularly scheduled during the usual sleep period, overlapping with sleep period and requiring adjustment of sleep & wake times
symptoms: - insomnia when trying to go to sleep
- excessive sleepiness when a person needs to be awake & alert
- sleep debt
- difficulty waking
- reduction in total sleep time
bright light therapy as a treatment for sleep disorders
- timed exposure to intense light which aims to shift the sleep-wake cycle to a desired schedule
- received by eyes for transmission to the SCN, which will influence melatonin secretion from pineal gland
DSPS: light exposure in morning hours to help advance circadian rhythm to earlier time
ASPD: exposure in early evening to delay circadian rhythm by a few hours
shift work: exposure in the evening to help someone who works nights to be more alert
zeitgebers
environmental time cues
- light is strongest zeitgeber
> daylight, blue light
- eating & drinking patterns
- temperature
- anything that can signal time
entrainment
when the SCN adjusts or resets the sleep-wake cycle through the influence of a zeitgeber, circadian rhythm is entrained
> adjusts activity in relation to time cues
light (zeitgeber)
- primary zeitgeber for the circadian rhythm
- can directly affect sleep by making it difficult to fall asleep
- can indirectly affect sleep by influencing timing of SCN activity, as it signals SCN to send inhibitory message to pineal gland, suppressing release of melatonin & therefore our preferred time to sleep
> daylight
> blue light
daylight (zeitgeber)
- sleep wake cycle becomes closely synchronised with sunrise & sunset
- exposure to daylight in morning & afternoon pushes sleep wake cycle forward to an earlier time
- pushed back to later by light exposure in evening
- sleeping with a light on interferes with NREM-REM sleep cycle & affects sleep quality
blue light (zeitgeber)
- biggest impact on circadian rhythm
- comes from the sun, TV, phone, computer
- suppresses secretion of melatonin
- too much exposure in the evening disrupts circadian rhythm
- using devices with blue light before bed keeps us alert, prolongs sleep onset, shortens total sleep time
- can cause a phase shift resulting in DSPS
- no use of electronic devices 30-60 mins before sleep
temperature (zeitgeber)
- core (internal) body temp & sleep are closely related
- follows a 24 hr circadian rhythm linked with sleep wake cycle
- falls during nighttime and rises during day
- adjusting bedroom temp to 18 degrees can signal to the body that it is time for sleep
eating & drinking patterns (zeitgeber)
- eating/drinking schedule and sleep-wake schedule should be aligned
- erratic eating patterns have detrimental effects on sleep- wake cycle
- well timed eating & drinking routine stabilises sleep-wake cycle
- alcohol can induce sleep, but shorten duration & quality
sleep hygiene
sleep habits that improve & maintain good sleep and full daytime alertness
- behaviours & environmental factors
inappropriate sleep hygiene practices
- irregular sleep onset & wake times
- stimulating & alerting activities before bedtime
- consuming stimulants too close to sleep time
good sleep hygiene practices
- regular sleep schedule & bedtime routine
- associate bedroom with sleep & not other activities
- avoid stimulating activities in the hour before bed
- avoid napping during wake period
- get up when u cannot sleep
- avoid large meals close to bedtime
- make sure room is right temperature (17-19 degs)
- ensure adequate exposure to natural light to help wake up
- sleep in complete darkness with no lights on
- dont use electronic devices 30-60 min before bed
