VCE psych U4 AOS 1

consciousness

Consciousness is the awareness of your own internal mental processes, including your thoughts, feelings, sensations and perceptions, and your awareness of the external world around you

why is consciousness a psychological construct

it can't be objectively observed or measured through collection of data

normal waking consciousness

a state associated with being aware of our internal and external environments

experience in every day activities when we are awake and have a regular level of awareness

can manage attention and behaviour, thoughts and perceptions are organised and clear

altered states of consciousness

any state that differs in awareness from normal waking consciousness

levels of awareness are lower or higher than in normal waking consciousness

naturally occurring altered states of consciousness

occur without external influence for example sleep, or a state of fatigue

Induced altered states of consciousness

a type of altered state of consciousness that occurs due to a purposeful action or aid for example alcohol induced state or an anaesthetised state

sleep

naturally occurring and reversible altered state of consciousness, characterised by a reduction in awareness and responsiveness to external surroundings

NREM (non-rapid eye movement) sleep

a type of sleep characterised by a progressive decline in physiological activity

~ 80% of a sleep episode in people of school age and older

N1

a transitional phase between wakefulness and sleep.

considered to be light sleep.

physiological responses begin to slow down including brain activity, heart rate and body temp.

if a person is not disturbed for a couple of minutes in N1, a person quickly moves into N2

N2

also considered light sleep

physiological responses continue to slow down

person can still wake relatively easily however bursts of brain activity help resist being woken by environmental stimuli such as noise

experienced the most throughout a sleep episode

N3

deep sleep

physiological responses are at their slowest and a person is most difficult to wake up

known as 'slow-wave sleep' - brain activity is at its slowest

experienced more in first half of sleep episode than second half

REM sleep

eyes make quick darting movements behind their closed eyelids

physiological activity increases

brain activity resembles wakefulness

voluntary muscles are seeming paralysed - twitch only intermittently

most vivid and memorable dreams occur

~ 20% of sleep for 5 and older

if you have less sleep than normal you may have more REM when you next sleep

hypnograms

line graph of a person's sleep mapped over time

displays patterns of a sleep episode

EEG (electoencephalography)

detects, amplifies and records electrical activity of the brain (brainwaves)

scalp electrodes measure voltage fluctuations induced by the mass electrical activity of neurons

EMG (electromyography)

detects, amplifies and records the electrical activity of skeletal muscles

can be used on face or body muscles

EOG (electrooculography)

detects, amplifies and records electrical activity of the muscles that allow the eye to move (only infers eye movement)

electrodes placed around the eye

Sleep diaries (subjective)

often used when a person is having sleep troubles

helps sleep experts understand the participant's experience

video monitoring (subjective)

record externally observable physiological responses throughout a sleep episode

recordings can also help participants become more aware of their behaviour

strengths of objective data

quantitive date - easy to measure and compare

minimal interpretations required - minimises bias

more accurate and reliable data - allows for replication

limitations of objective data

can lack details - no insight gained as to why measurements obtained

can be more artificial and less external validity as measurements taken in a laboratory

strengths of subjective data

provides qualitative data, thus is more detailed

can provide insight into mental processes that can't be directly measured for example dreams

limitations of subjective data

qualitative - can be difficult to measure and compare

requires personal judgements and interpretations - often influenced by bias

less valid and reliable due to bias - more difficult to replicate

circadian rhythms

biological processes in all animals that coordinate the timing of activity of body systems over a 24-hour period

allow for optimised functioning at certain time points over 24 hours

controls our sleep-wake cycle, release of hormones, regulation of body temp

biological rhythms

repeated biological processes that are regulated by internal mechanisms

ultradian rhytms

biological processes that coordinate the timing of activity of body systems over periods of less than 24 hours

may last from a few minutes to hours

SCN (suprachiasmatic nucleus)

found in the hypothalamus

synchronises and controls the body's circadian rythms

at specific times during the 24 hour day the SCN sends signals to regulate various activities in the body

can function independently to maintain approx 24 hour cycle because of feedback loop

zeitgebers

external cues that influence SCN

Process of SCN and melatonin

1. Light sensitive neurons in the retinas of the eyes detect incoming light and send messaged to the brain's SCN about the amount of light

SCENARIO 1

2. no light detected - SCN sends excitatory neural signal to pineal gland

3. pineal gland releases melatonin

4. melatonin induces sleepiness and decrease cell activity

SCENARIO 2

2. light detected

3. SCN sends inhibitory nueral signals to pineal gland

neonatal period

· 0 - 1 month old

· sleep for up to 16 hours each day

· each sleep episode is about 2 - 4 hours - wake for feeding, etc.

· sleep cycle does not align with circadian rhythm - due to ongoing neurological development

· REM sleep first - approx 50% of sleep

· NREM approx 50%

· Neonates may actively move their faces and limbs during REM - support brain and nervous system development

infancy period

· 2 - 12 months

· total of 13 - 15 hours of sleep - sleep episodes last 5-8 hours per night

· Circadian rhythm develops a more regular sleep pattern following a day-night cycle

· Interactions between SCN and melatonin begin to synchronise with 24 hour circadian rhythm

proportion of REM and NREM for infants

REM - 35-40%

NREM - 60-65%

childhood

· 2 - 11 years old

· total of 9-11 hours of sleep

· timing of circadian rhythm gradually delays

NREM and REM of childhood

REM - 20%

NREM - 80%

2-5: N3 > half of NREM

6-10: N1 and N2 increase and N3 decreases

adolescence

· 11 - 18 years old

· total of 8 - 11 hours of sleep - steadily declines throughout adolescence

·delay in circadian rhythm due to hormonally determined shift in melatonin release - preference for a later bed time

wake after sleep onset (WASO)

state of wakefulness experienced by an individual after the onset of sleep that can occur periodically throughout an episode of sleep

early to middle adulthood

· 19 - 50 years old

· 7 - 9 hours

· N3 sleep decreases - more time in N1 and N2

· more frequent WASO

older adult

· 50+

· 6 - 7 hours of sleep a day - significant decline in N3 sleep

· more WASO

· SCN decreases

partial sleep deprivation

the experience of achieving inadequate sleep in terms of quantity and/or quality

starts at about 17 hours without sleep

equivalent to the effects of 0.05% BAC

affective component of partial sleep deprivation

· trouble regulating or controlling emotions

· mood swings or emotional outbursts

behavioural component of partial sleep deprivation

· decreased control in balance and coordination

· slower reaction times

· may participate in more risk taking or impulsive behaviour

· children may be hyperactive and have increased misbehaviour

cognitive component of partial sleep deprivation

· memory trouble

· decreased alertness

· lack of motivation

full sleep deprivation

· no sleep for 24 hours

· effects are more severe than partial sleep deprivation

· impairs physical wellbeing - obesity, diabetes, heart problems

· impairs psychological wellbeing - hallucinations, depersonalisation, depression, anxiety

equivalent to the effects of 0.10% BAC

circadian rhythm sleep disorders

persistent pattern of sleep disruption due to a misalignment between the circadian rhythm and the sleep–wake schedule required by a person

delayed sleep phase syndrome (DSPS)

• delay in the timing of sleep onset and awakening, compared with the timing that is desired (delay is usually 2 or more hours)

• delay in sleep onset contributes to a sleep disorder when a person is unable to achieve their recommended amount of sleep

• more common in teenagers and young adults

• main effect is sleep deprivation

advanced sleep phase disorder (ASPD)

• an advance in the timing of sleep onset and awakening compared to the timing that is desired (fall asleep 2 or more hours earlier)

• When a person with ASPD attempts to adhere to alater bedtime, they may continue to have an early wake time due to the shift in their circadian rhythm

• More common in middle-aged and older adults

• main effect is feeling sleepy in the early evening and struggling to stay awake

shift work sleep disorder

• shift work can cause sleep disorder when a person regularly works outside of normal business hours, particularly at night and the very early morning

• symptoms can reduce if person spends longer than one shift rotation before changing (minimum 3 weeks)

• Where rotating schedules are required, they should ideally shift forward, such as from morning shift, to afternoon shift, to evening shift, to allow a person the best chance to adjust

• main effect is distress and dysfunction due to excessive sleepiness at work and impaired sleep at home after their shift

improving sleep hygiene - temperature

• COOL ROOM, WARM BEDDING

• Regulating temp can help initiate sleep quickly and maintain sleep

• Having a warm shower before bed promotes relaxation, getting into cool air cools the body to promote sleep onset

improving sleep hygiene - light

• Blue light inhibits melatonin

• Expose eyes to light at ideal times (NOT before bed)

• Stop exposure to bright and device lights 1-2 hours before bed

bright light therapy

• exposing a person to different light intensities for a specific amount of time to reset the sleep–wake cycle.

• 20-60 minutes is recommended

• most effective when timed exposure to light occurs over several days.

improving sleep hygiene - eating and drinking patterns

• Don’t try not to eat a full meal less than 4 hours before bedtime

• Limit caffeine intake later in the day