Psych unit 4 AOS 1

Psychological constructs

An agreed upon description and understanding of psychological phenomena

that cannot be overtly measured or observed

What are psychological constructs used for?

• To understand or explain things that we believe exist but cannot

  • see,

  • touch,

  • or measure in any way.

• Researchers rely on

  • info provided by the individual,

  • behaviour that is shown

  • physiological changes

Normal waking consciousness (NWC)

• The ability to be aware of our internal and external stimuli

• The ability to voluntarily direct our awareness and attention

Altered states of consciousness (ASC)

Any state of consciousness that deviates from normal waking consciousness, in terms of marked differences in the levels of:

• awareness

• thinking

• sense of time, etc

Naturally occurring altered state of consciousness

A type of altered state of consciousness that occurs without intervention

• e.g. sleep

Induced altered state of consciousness

A type of altered state of consciousness that occurs due to a purposeful action or aid

e.g. meditation

What is sleep?

A regular and naturally occurring altered state of consciousness

• involves a loss of awareness and disengagement with internal and external stimuli.

Sleep episode

The full duration of time spent asleep

Sleep cycle

A proportion of the sleep episode in which the sleeper progresses through stages of REM and NREM sleep

• on average: 90mins

Eye movements: REM vs NREM

NREM: Non-rapid eye movements

REM: Rapid, jerky eye movements

Brainwaves REM vs NREM

NREM: high amplitude, low frequency

REM: high frequency, low amplitude

Physiological arousal REM vs NREM

NREM: Decreases (heart rate, breathing)

REM: Increases (heart rate, breathing)

Muscles REM vs NREM

NREM: Some movement

REM: State of paralysis (muscle atonia)

Dreams REM vs NREM

NREM:

• Short lived

• Not likely to be vivid or recalled

REM: Common and likely to be recalled

Duration REM vs NREM

NREM:

• Approx. 80% of the night’s sleep

• decreases in proportion as the night progresses

REM:

• Approx. 20% of the night’s sleep

• increases in proportion as the night progresses

Purpose NREM vs REM

NREM: Physical restoration and memory consolidation

REM: Optimising neural pathways & emotional processing

NREM sleep definition

A period of sleep subdivided into three different stages

• the sleeper does not experience any rapid eye movement.

REM sleep definition

A period of sleep where the sleeper experiences rapid eye movement beneath closed eyelids.

NREM stage 1

• light stage of sleep

• easily awakened: low arousal threshold 

lower levels of bodily arousal, decrease in:

• heart rate

• respiration

• body temperature

NREM stage 2

• truly asleep

• more intense stimuli than stage 1 to awaken: higher arousal threshold

Physiological changes:

• Fewer body movements

• eye movements stop 

• breathing→more regular

• heart rate → slower

NREM stage 3

• deepest stage of sleep- highest arousal threshold 

• Muscles→ completely relaxed

• No eye movement

• Heart rate, blood pressure and body temperature → lowest and most regular

Physiological sleep measures

• electroencephalograph (EEG)

• electromyograph (EMG)

• electro-oculograph (EOG)

Subjective sleep measures

• sleep diaries

• video monitoring

Electroencephalograph (EEG)

a device that detects, amplifies, and records the electrical activity of the brain.

• Electrodes placed onto scalp- picks up signals & represent them in brain wave patterns.

Brain waves & consciousness

The frequency and amplitude of brain waves can indicate what state of consciousness an individual is experiencing.

• Frequency- rate

• Amplitude- height

Electromyograph (EMG)

A device that detects, amplifies and records the electrical activity of muscles.

• Higher level of muscular activity - more alert

Electro-occulargraph (EOG)

A device that detects, amplifies, and records the electrical activity of the muscles that move the eyes. 

• Electrodes- attached to areas around the eyes. 

• Used for REM/NREM measure. 

DARE acronym- used for physiological sleep measures

Detects

Amplifies

Records

Electrical activity

Sleep diaries

A record containing self-reported descriptions from an individual about their sleeping periods

• recorded over a period of time

• includes:

  • duration of sleep

  • quality of sleep

  • number of sleep disruptions, etc

Video monitoring

The use of camera and audio technologies to record an individual as they sleep

• Usually paired with physiological measures

• gives validity to a phenomenon

Circadian rhythm

Biological and behavioural changes that occur as part of a cycle that lasts around 24 hours.

e.g. sleep wake cycle

Ultradian Rhythm

Biological and behavioural changes that occur in a cycle that lasts less than 24 hours.

e.g. REM and NREM sleep cycles

The Suprachiasmatic Nucleus (SCN)

An area of the hypothalamus that is responsible for regulating an individual’s sleep-wake patterns.

Where does the SCN receive information from?

• External cues: info from environment

  • e.g presence or absence of light

• Internal cues: info that originates within the body

  • e.g. expression or suppression of clock genes

SCN’s role in melatonin release

1. SCN receives external cues (lights off) and internal cues (clock genes).

2. SCN sends neural messages to the pineal gland

3. Pineal gland produces and releases melatonin into bloodstream

4. Promotes feelings of calm and relaxation- therefore promotes sleep.

Melatonin

A hormone released by the pineal gland typically at night-time to induce sleep as part of the sleep-wake cycle.

Cortisol’s Role in the Sleep Wake-Cycle

A hormone released by the adrenal glands in the morning to increase alertness, wakefulness and maintain heightened arousal, thereby regulating the sleep-wake cycle. 

• High levels in the morning and low levels at night

What is the sleep wake cycle regulated by?

biological mechanisms:

• Circadian rhythms

• ultradian rhythms

• the SCN

• melatonin

Sleep Wake Cycle

A type of circadian rhythm – 24-hour-cycle made up of time spent sleeping and time being awake and alert.  

neonatal period characteristics of sleep (1-15 days)

Sleep duration ~ 16 hrs.

Sleep episode ~50% REM, ~50% NREM.

• brief awakenings during the sleep episode

infancy period characteristics of sleep (3-24 months)

Sleep duration: ~13.5 hrs.  

Sleep episode: ~35% REM, ~65% NREM. 

Compared to adults

• brief awakenings

• < amount of sleep cycles

• Shorter sleep cycles

Childhood characteristics of sleep (2-14 years)

Sleep duration: ~11 hrs.

Sleep episode: ~20% REM, ~80% NREM. 

Adolescence characteristics of sleep (14-18 years)

Sleep duration: ~9 hrs.

Sleep episode: 20% REM, 80% NREM.

- DSPD: biological delayed sleep onset:

• melatonin released 1–2 hrs later

Adulthood characteristics of sleep (18-75 years)

Sleep duration: ~7-8 hrs.

Sleep episode: 20% REM, 80% NREM.

Compared to infants

• more likely to experience one full sleep episode- less wakeups

• less sleep cycles

• longer sleep cycles

Old age characteristics of sleep (75+ years)

• Sleep duration: ~6 hrs.

• Sleep episode: 20% REM, 80% NREM.

• ASPD: biological shift forward in sleep-wake cycle. 

• Wake up more frequently throughout the night.

• NREM3 sleep→ decreases, replaced mostly by NREM2 sleep.

Explanations for Notable Differences in Sleep Across the Lifespan 

Sleep requirements change because physical and cognitive needs change over time. 

• REM = important for brain and cognitive development and rest.

• NREM = important for physiological rest and development.

Neonatal period and infancy- explanation for sleep characteristics

• No established circadian rhythm – sleep distributed across the full 24 hour day. 

• Significant time spent in REM sleep due to rapid brain development.

Infancy

• Growth, development, rapid physiological changes- begin to have a fairly consistent circadian rhythm. 

Childhood- explanation for sleep characteristics

Time spent in REM sleep starts to reduce as the pace of brain development steadies.

Adolescence- explanation for sleep characteristics

• Social factors decrease proportion of sleep – waking up early for school, social commitments during the nighttime. 

Adulthood and old age- explanation for sleep characteristics

Lower levels of sleep due to:

- Ill health and increase prevalence of sleep disorders.

- Reduced amount of cognitive and physical growth.

Partial sleep deprivation

inadequate sleep based on an individual’s needs (quantity/quality)

Total sleep deprivation

when an individual has no sleep within a 24-hour period

Effects of partial sleep deprivation

Affective effects

Behavioural effects

Cognitive effects

Affective effects of sleep deprivation

Amplified emotional responses

• Increased irritability

• Depressed mood

• Heightened anxiety

• Decreased motivation

Behavioural effects of sleep deprivation

Observable actions

• reduced motor control

• reduced spatial awareness

• slower reaction times

• microsleeps

Cognitive effects of sleep deprivation

internal mental process

• decreased ability to concentrate and direct attention

• poorer performance on tasks involving problem solving or logical reasoning

• Increased forgetfulness

Partial Sleep deprivation compared to BAC

The effects of a BAC level of 0.05 are roughly equivalent to 17 hours of sleep deprivation.

Total Sleep deprivation compared to BAC

The effects of a BAC level of 0.10 are roughly equivalent to 24 hours of sleep deprivation

Affective effects of sleep deprivation compared to blood alcohol concentration

Can both impact a person’s affective functioning

Sleep deprivation: negative effects

Alcohol: range of effects

• happy

• excited

• angry

• sad

Cognitive effects of sleep deprivation compared to blood alcohol concentration

Both have cognitive impairments that include:

• reduced speed in processing and understanding information

• decreased ability to reason and problem solve

• greater difficulty making sense of the world

Circadian Rhythm Sleep Disorders definition

Sleep disorders that interfere with the typical regulation of the circadian rhythm of sleep

• leads to a change in the sleep-wake cycle. 

Circadian Rhythm Sleep Disorders features

• SCN may receive external and internal cues at abnormal times. 

• Misalignment b/w circadian rhythm and sleep-wake cycle

• Disruption to typical sleep-wake cycle:

  • biological issues e.g. shift later for adolescents

  • lifestyle changes e.g. shift work. 

Bright light therapy

A treatment for sleep-related problems used to adjust a person’s misaligned circadian rhythm through exposure to a high-intensity light source.

Bright Light Therapy and the SCN

1. Exposure to bright light source.

2. SCN receives this as an external cue.

3. Triggers pineal gland to inhibit the release of melatonin→ promoting wakefulness (for DSPS- release melatonin earlier at night)

4. Readjusts the circadian rhythm so that the individual is sleeping and waking at desired time.

Factors Essential to Successful Bright Light Therapy 

1. Appropriate timing of exposure sessions: when a person is feeling tired

2. The right amount of light: min. 15 minutes + min of 2 weeks

3. Safe exposure: a person should not look directly at the light

Delayed Sleep Phase Syndrome (DSPS) 

A type of circadian rhythm sleep disorder in which sleep and waking occur later than typical. 

• occurs during adolescence

• involves delayed melatonin secretion.

Causes of Delayed Sleep Phase Syndrome (DSPS) 

A misalignment between internal and external cues that regulate a circadian rhythm

• external cues are received at appropriate time

• internal cues are not

• (melatonin release later than usual).

Bright Light Therapy for DSPS

Morning at appropriate waking time

• external cue to SCN→ promotes wakefulness by sending signals to pineal gland to inhibit melatonin release

• promotes melatonin release earlier in the night → reset circadian rhythm, promoting sleep.

Advanced Sleep Phase Disorder (ASPD) 

type of circadian rhythm sleep disorder in which sleep and waking occur earlier than typical, due to a misalignment of internal and external cues

Advanced Sleep Phase Disorder (ASPD) causes

Problems with internal cues resulting in a misalignment between external and internal cues that regulate the circadian rhythm

- Melatonin secretion occurs earlier = sleep and wake earlier.

Bright Light Therapy for ASPD

Evening when feeling sleepy

• external cue to SCN→ promotes wakefulness.

• Helps SCN send signals for later melatonin release→ delayed onset of sleep

Shift Work

An occupation that involves working at unusual hours, including overnight.

• Cause of circadian rhythm sleep disorders rather than being a sleep disorder itself. 

Shift Work causes

• External cues→ individual is required to be awake when dark and sleep when it's light→ unusual sleep times. 

Why does shift work result in poor sleep

Work hours out of sync with internal cues

• Sleeping during daylight reduces melatonin→ poor sleep quality and daytime fatigue.

• Working at night→ increases zeitgebers which make it more difficult to stay awake

Impacts of shift work on sleep

• Poor sleep quantity and quality→ sleep debt

• Insomnia

• Fragmented sleep

Bright Light Therapy for shift work

Before beginning of shift

• promote wakefulness when they need to be awake and alert.

• Promote sleepiness at a later, more suitable time

Sleep Hygiene 

The practices and habits that promote an individual’s sleep patterns

• Makes it easier to fall asleep at appropriate times

• Improves sleep quality and quantity. 

What to avoid to promote sleep hygiene?

• Activities other than sleeping in bed (studying or watching TV)→ weakens association of bed and sleep.

• Exercise close to sleep time

Actions to promote sleep hygiene

• Sleeping and waking at a consistent time each day

• Sleeping in a quiet place.

• Sleeping in a comfortable space.

Mental wellbeing

an individual’s psychological state, involving their ability to think, process information, and regulate emotions

How can sleep hygiene improve mental wellbeing

1. Adequate quality and quantity of sleep- important for good mental wellbeing→ link b/w poor sleep and mental illness

2. sleep hygiene enables an adequate quality and quantity of sleep→ therefore improves mental wellbeing

Zeitgebers 

External cues from the environment that influence the circadian rhythm

• light

• temperature

• eating and drinking patterns

• exercise.

Used by SCN to adjust circadian rhythms. 

Blue light as a Zeitgeber

A type of light that can be emitted both

• naturally: daylight

• artificially: technology

Daylight as a Zeitgeber

The typical light an individual is exposed to during the day, and is mostly natural blue light. 

How does light regulate the sleep wake cycle?

By signalling to SCN to cease melatonin production and promote wakefulness

• Exposure to light at night→ reduces sleepiness

Temperature as a Zeitgeber

The degree of external heat in the environment that can influence the quality and quantity of sleep.

• link between having a cool room temperature and improved quantity and quality of sleep

Timing of meals as a zeitgeber

• Eating too close to sleep time→ harder to fall asleep

• due to stimulation of the digestive system→ reduced quality and quantity of sleep

• meals should be consumed a couple hours before sleep

Volume of meals as a zeitgeber

• Going to sleep hungry = poorer sleep quality and quantity.

• Large meals close to sleep = impair sleep patterns. 

Effect of caffeine on sleep

A stimulant that increases the activity of the NS, promoting wakefulness.

• Blocks sleep-promoting neurotransmitters.

Effect of Alcohol on sleep

a depressant that increases feelings of tiredness making it easier to fall asleep

• negatively impacts quality of sleep. 

Effect of spicy foods on sleep

increase body temp, impairing sleep as cooler body temps promote sleep.

• can stimulate metabolic processes→ more difficult to fall asleep. 

Effect of high sugar high-fat foods on sleep

negatively impact quality and quantity of sleep.

What is the relationship b/w sleep and mental wellbeing?

Bidirectional relationship→ influence each other

• Poor sleep→ can negatively affect wellbeing→ irritability, low mood, difficulty managing emotions.

• Poor wellbeing→can negatively affect sleep→stress or anxiety making it difficult to fall asleep or stay asleep + impact of cortisol