Psych U4 AOS1

consciousness

awareness of our own thoughts, feelings and perception

• personal

• selective

• continuous and changing

Psychological construct

A concept to explain things that we believe exist but cannot see, touch or measure in any objective way

• sleep is a psychological construct

• altered state of consciousness, neutral and regularly occurring

  • loss of awareness and disengagement with internal and external stimuli

Normal Waking Consciousness (NWC)

state of consciousness in which we are aware of our thoughts, memories, feelings and the sensations we experience from the outside world

Altered state of Consciousness (ASC)

distinctly different state of awaresness in comparison to NWC

• with major changes in qualities of one’s thoughts, feelings and perceptions.

• ASC neutral state

  • An ASC that occurrs spontaneouslt wthout any intentional effort (sleep, daydreaming)

• ASC induced state

  • An ASC that is intentionally triggered through conscious efforts (substance intake)

NREM (non rapid eye movement)

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

• as NREM progresses, movements decrease

• makes up 75-80% of sleep episode

NREM 1

Transitional phase from wakeness to sleep (light sleep)

• brain activity, heart rate, body temperature go down

• easily waken

• loss of self awareness and their surroundings

• still aware of faint sounds in environment

NREM 2

• experienced the most during sleep episode

• bursts of brain activity resist being woken up easily

• 50% of sleep episode

NREM 3

deep sleep

• physiological responses at its slowest

• difficult to wake

• if woken, sleeper is likely to feel dorwsy and disoriented

• sleepwalking/talking usually occurrs during this stage

• adolescents likely to experience more compared to adults

• more in first half of episode

REM (Rapid eye movement)

A type of sleep characterised by the quick darting of the eyes behind the closed eyelids, and an increase in brain and physiological activity

REM sleep characteristics

• highly active brain, less active body

• sleeper is in a pralysed state

• makes up 20-25% of sleep episodes for most age groups

• amount of time spent in REM increases as sleep episode progresses

• largest amount occurrs just before waking up

Sleep episode

the full time spent asleep

sleep cycle

made up of multiple repeated stages of REM and NREM, lasting for approximately 90 minutes

• after first cycle, we skip N1 and go straight to N2

• by third cycle ~ we do bnot enter N3

• our time in REM increases as sleep duration increases

• we usually emerge from N2 when we naturally awake

EEG (brain scan)

Detects, amplifies and records electrical activity of the brain

• attatched to the surface of the scalp

• useful for sleep studies or diagnosis of patients brain damage or disorders

• As amplitude goes higher, there is less brain activity (deeper sleep)

• As frequency goes lower, there is less brain activity (deeper sleep)

EMG (body’s muscles)

Detects, amplifies and records the electrical activity of the body’s muscles

• can be used to identify the different stages of sleep

• REM → low electrical activity

• NREM → medium/moderate electrical activity

• as NREM approaches N3, activity decreases.

EOG (eye muscles)

Detects, amplifies and records the electrical activity of the muscles surrounding the eyes.

• REM → high electrical activity

• NREM → low electrical activity

Circadian rhythm

biological processes that coordinate the timing of bodily activities over a 24 hour period

• sleep wake cycle is endogenous (from within)

• external cues influence time giving cuesm keeping us in a 24 hour day-night sync

• Regulated by the suprachiasmatic nucleus (SCN) within the hypothalmus

Ultradian rhythm

biological processes that coordinate the timing of bodily activities over a period of less than 24 hours

• one sleep cycle is considered an ultradian rhythm cycle

SCN (suprachiasmatic nucleus)

Area of hypothalmus that is responsible for regulating one’s sleep wake pattern/cycle

• maintains internal body clock

• responds to light control and the production of melatonin

  • cues are dictative of messages sent to pineal gland, responsible for release and production of melatonin

• receives information from both external and internal cues to moderate the circadian rhythms

  • external cues (Zeitgeber)

    • From environment, absence/presence of light

  • internal cues

    • originates from within body, nutrients, meals, caffeiene

Melatonin in sleep

higher at night, lower in morning

• released by pineal gland, typically at night, to induce sleep as part of the sleep wake cycle

• promotes a state of calm and relaxation to aid sleep

• levels rise at the onset/presence of darkness

Cortisol

released in morning

• responsible for increasing alertness and maintaining heightened arousal

• released from adrenal cortex

importance of NREM and REM

• REM → important for brain and cognitive development, and rest

• NREM → physiological rest and devlopment

  • hence babies’ high level of REM sleep due to rapid brain development

Newborns sleep (0-3 months)

• 50:50 NREM and REM sleep

• sleep onset starts in REM, as opposed to N1

• 17 hours sleep time (not 17 straight) ideally

• circadian rhythms no developed yet

  • melatonin release

Childhood sleep (2-12 years)

• greater % of time spent in NREM 3

• child might ‘skip’ the first REM sleep in the first two cycles due to intensity of slow wave sleep (NREM)

• 11-14 hours of sleep time (ideally)

• 25% REM, 75% NREM

Adolescents sleeo (13-17)

• ideally 9-10 hours

• 20% REM, 80% NREM

• will often experience hormonal changes which cause delay in melatonin release

→ leading to a tendency to sleep later (later sleep onset)

Adults sleep (18-64 years)

• 8 hours of total sleep

• 20% REM, 80% NREM

• N3 steadily declining

Older adults sleep (65+)

• 7 hours full sleep (ideally)

• 20% REM, 80% NREM

• little to no NREM 3 sleep

• more awakenings during night

• earlier sleep onset, tendency to go to sleep earlier and wake earlier in the morning

Full sleep deprivation

• sleep deprvation for 24 hours

Partial sleep deprivation

• sleep deprivation for some duration with 24 hours

• OR sleep duration is too short in accordance to recomended amount of sleep for age

• based on individual needs

Affective effects of sleep deprivation (Abc)

• changes in emotions

• heightened agression/irritability

• increased negative emotions

• amplified emotional response

Behavioural effects of sleep deprivation (aBc)

• delayed reaction time

• motor control worsened

• clumsiness

Cognitive effects of sleep deprivation (abC)

• impairment of memory

• lapse of attention

• reduced concentration

Sleep and BAC

Alcohol has similar effects to sleep deprivation

• the higher then BAC, the greater the impairment of cognition, behaviour, affective

• BAC of 0.05 → 17 hours of sleep deprivation

• BAC of 0.10 → 24 hours of sleep deprivation

DSPS (delayed sleep phase syndrome)

• sleeping and waking occurs later than usual

• delayed sleep wake cycle

• melatonin secretion occurs later

ASPD (advanced sleep phase disorder)

• sleep and waking earlier than usual

• sleep wake cycle is advaced

• melatonin secretion occurs earlier, thus sleeping and waking earlier

Bright light therapy (works to readjust circadian rhythms)

• triggers SCN with light, supresses melatonin release, promoting wakefulness

• supresses pineal gland release

• expose to light in the MORNING (6-8am) helps with DSPS

  • encourages wakefulness in the morning

• expose to light in EARLY EVENING when feeling sleepy (7pm-9p) helps with ASPD

  • encourages individuals to stay awake for longer

sleep hygiene

practices and patterns and environments that are beneficial for one’s sleep patterns

• lack of sleep hygeine involves worsening quality of sleep and worsened sleep patterns

Zeitgebers - Light

• signals to SCN for wakefulness

• bluelight

Zeitgeber - Temperature

• linkbetween having a cool room and improved quality and quantity of sleep (body temp decreases during sleeping, therefore a cooler room helps with that)

• ideal room temp 19-20 degrees celcius

Zeitgeber - eating and drinking patterns

• what, when, quantity of food and drinks consumed

• alcohol, caffeine, spicy foods, high sugar and fat foods can negatively impact sleep patterns

• eating too close to sleep time can disrupt sleep

• going to sleep hungry can also lead to poor sleep