Psych SAC 4

Consciousness

A level of awareness an individual has of their thoughts, feelings, perceptions and existence.

Psychological construct

An agreed-upon description and understanding of psychological phenomena that cannot be directly measured or observed.

Consciousness continuum

A visual representation of different states of consciousness, progressing from lower to higher levels of awareness.

Normal waking consciousness

A state of consciousness in which an individual is awake and aware of internal and external events, including thoughts, feelings and behaviour.

Altered state of consciousness

A state of consciousness distinctly different from normal waking consciousness in terms of the quality of experience and level of awareness.

Sleep

A regular, naturally occurring altered state of consciousness involving reduced awareness and disengagement from internal and external stimuli.

Sleep cycle

An approximately 90-minute period in which an individual progresses through stages of NREM and REM sleep before repeating.

Hypnogram

A graph representing the duration of each sleep stage and transitions between them.

REM sleep

A type of sleep characterised by rapid eye movements, high brain activity and low physical activity.

NREM sleep

A type of sleep characterised by a lack of rapid eye movements and divided into three stages.

REM vs NREM: eyes

REM: fast, jerky eye movements. NREM: slow or minimal eye movement.

REM vs NREM: brainwaves

REM: beta-like waves. NREM: theta and delta waves.

REM vs NREM: body

REM: muscle paralysis. NREM: movement is possible.

REM vs NREM: heart rate

REM: heart rate increases. NREM: heart rate decreases.

REM vs NREM: dreams

Dreaming is common in REM; dreams can also occur in NREM but are generally less vivid.

REM vs NREM: percentage

REM makes up approximately 20% of sleep; NREM makes up approximately 80%.

REM vs NREM: function

REM is associated with mental restoration; NREM is associated with physical restoration.

Brainwave types

Gamma, beta, alpha, theta and delta.

Physiological indicators of consciousness

Objective measures including heart rate, body temperature, galvanic skin response, eye movement, muscle movement and brain waves.

Psychological indicators of consciousness

Subjective measures including content limitations, perceptual and cognitive distortions, emotional awareness, self-control and time orientation.

EEG

Electroencephalography detects, amplifies and records electrical activity of the brain by measuring brainwave frequency and amplitude.

EMG

Electromyography detects, amplifies and records electrical activity of the body's muscles.

EOG

Electro-oculography detects, amplifies and records electrical activity associated with muscles surrounding the eyes.

Beta waves

High frequency and low amplitude; associated with being awake and alert and beta-like activity during REM.

Alpha waves

Medium-high frequency and low-medium amplitude; associated with relaxed wakefulness and NREM1.

Theta waves

Low-medium frequency and medium-high amplitude; associated with NREM2.

Delta waves

Low frequency and high amplitude; associated with NREM3.

EEG during REM

Beta-like brainwaves.

EEG during NREM

Theta and delta brainwaves.

EOG during REM

High eye activity.

EOG during NREM

Slow, rolling eye movements.

EMG during REM

Very low muscle activity or muscle paralysis.

EMG during NREM

Some muscle movement is possible.

Sleep diary

A subjective measure recording sleep duration, sleep quality, thoughts and feelings before sleep and after waking, behaviours around sleep, and the number of sleep disruptions.

Video monitoring (whats recorded)

Uses cameras and audio to record sleep/wake periods, movements, activities and sounds during sleep.

Advantage of video monitoring

Can observe behaviours during sleep and can be combined with physiological measures to validate findings.

Limitation of video monitoring

Interpretation can be subjective; for example, it may be difficult to determine whether someone getting out of bed is awake or sleepwalking.

Biological rhythms

Repeated biological processes regulated by internal mechanisms.

Circadian rhythm

A biological or behavioural cycle lasting approximately 24 hours, such as the sleep-wake cycle.

Ultradian rhythm

A biological or behavioural cycle lasting less than 24 hours, such as the sleep cycle.

Melatonin

A hormone released by the pineal gland, particularly in low light, that promotes sleep as part of the sleep-wake cycle.

SCN + loco

The suprachiasmatic nucleus is located in the hypothalamus and acts as the body's biological clock.

SCN and melatonin

The SCN signals the pineal gland to release melatonin when light levels are low.

SCN and cortisol

The SCN supports the release of cortisol during periods of higher light and daytime activity.

Sleep across lifespan: neonatal (1-15 days)

Approximately 16 hours; 50% REM and 50% NREM.

Sleep across lifespan: infancy (3-24 months)

Approximately 13.5 hours; 35% REM and 65% NREM.

Sleep across lifespan: childhood (2-14 years)

Approximately 11 hours; 20% REM and 80% NREM.

Sleep across lifespan: adolescence

Approximately 9 hours; 20% REM and 80% NREM.

Sleep across lifespan: adulthood

Approximately 7-8 hours; 20% REM and 80% NREM.

Sleep across lifespan: old age (75+ years)

Approximately 6 hours; 20% REM and 80% NREM.

Zeitgeber

An external environmental cue that influences circadian rhythms, such as daylight or blue light.

Sleep deprivation

Inadequate quantity and/or quality of sleep.

Full sleep deprivation

Receiving no sleep for a period of approximately 24 hours.

Partial sleep deprivation

Receiving some sleep within a 24-hour period, but the duration is too short or the quality is poor.

Affective effects of sleep deprivation

Changes in emotions and emotional responses, including irritability, mood swings, heightened anxiety, reduced motivation, increased negative emotion, poorer emotional regulation, reduced empathy and increased aggression or impatience.

Behavioural effects of sleep deprivation

Changes in actions and ability to control them that arise from sleep deprivation, including:
Sleep inertia

• Excessive sleepiness during the day

• Increased likelihood in partaking in risk taking behaviours

• Fatigue

• Slow reaction time

• Reduced efficiency

• Reduced motor control

• Involuntary lapses to microsleeps

• Diminished social functioning

Cognitive effects of sleep deprivation

Changes in mental processing, including reduced concentration, impaired short-term memory, lapses in attention, impaired decision-making and problem-solving, reduced creativity and impaired visual-spatial ability.

BAC

Blood alcohol concentration; the amount of alcohol present in a person's bloodstream.

Alcohol and the nervous system

Alcohol is a depressant drug that slows the nervous system and decreases alertness, concentration, reflexes and decision-making.

Dawson and Reid (1997)

A BAC of 0.05 was found to be roughly equivalent to 17 hours of sleep deprivation, while a BAC of 0.10 was roughly equivalent to 24 hours of sleep deprivation.

Sleep deprivation and BAC

Both can impair emotional regulation, mental processing, reasoning, problem-solving and decision-making.

Sleep disorder

A disturbance to typical sleeping and waking patterns.

Circadian rhythm sleep disorder

A sleep disorder that interferes with the typical regulation of the circadian rhythm, causing changes to the sleep-wake cycle.

Delayed sleep phase syndrome

A circadian rhythm disorder where sleep and waking occur later than usual.

Cause of delayed sleep phase syndrome

Misalignment between internal and external cues; commonly associated with adolescence and a delayed sleep-wake cycle.

Treatment for delayed sleep phase syndrome

Bright light therapy early in the morning.

Advanced sleep phase disorder

A circadian rhythm disorder where sleep and waking occur earlier than usual.

Treatment for advanced sleep phase disorder

Bright light therapy before bed in the early evening.

Shift work

An occupation involving work during usual sleeping hours, such as overnight work.

Cause of shift work sleep disruption

External environmental cues are out of sync with the required work schedule.

Treatment for shift work sleep disruption

Bright light therapy before the shift begins.

Sleep hygiene

The practices and habits that promote healthy sleep patterns and improve sleep quality and quantity.

Light and sleep hygiene

Daylight and blue light influence circadian rhythms and sleep.

Temperature and sleep hygiene

A comfortable room temperature supports sleep; approximately 18°C is commonly recommended in these notes.

Eating and drinking and sleep hygiene

Eating too close to sleep, being hungry, large meals, caffeine, alcohol and certain foods can negatively affect sleep.

Time and sleep hygiene

Keeping a consistent sleep and wake schedule supports healthy sleep.

Sound and sleep hygiene

A quiet sleeping environment supports sleep.

Comfort and sleep hygiene

A comfortable sleeping environment promotes better sleep.

Bed association and sleep hygiene

Using the bed primarily for sleep can strengthen the association between bed and sleeping.

Exercise and sleep hygiene

Regular exercise can support healthy sleep patterns.