Chapter 6 - Sleep

Psychological construct

a theoretical concept used to describe psychological phenomena that are not directly observable

sleep as a psychological construct

a personal and internal experience that cannot be directly observed.

consciousness

Consciousness is the level of awareness an individual has over their thoughts, feelings, perceptions, and existence.

conscious as a psychological construct

cannot be objectively observed or measured through the collection of data, but it is widely understood to exist.

normal waking consciousness (NWC)

refers to the state of consciousness associated with being awake and aware of our internal and external environments e.g. relaxed state, focused/divided attention

Altered state of consciousness (ASC)

any state of consciousness that is significantly different from normal waking consciousness or any waking state in terms of level of awareness and experience. e.g. coma, sleep, alcohol induced, meditation, drowsy, daydreaming

Sleep as an ASC

ACEPTS - reduced Awareness, fewer Content limitations, reduced control of Emotions, Perceptual and cognitive distortions, less accurate understanding of passage of Time and reduced Self control.

naturally occurring

occurs without intervention (sleep, day dreaming)

induced

occurs due to a purposeful action or aid e.g. meditation, hypnosis, influence of alcohol

sleep

a regularly occurring altered state of consciousness that typically occurs naturally and is primarily characterised by partial or total suspension of conscious awareness.

sleep-wake cycle

the full 24-hour biological rhythm that includes a period of sleep (sleep episode) and a period of wakefulness.

sleep episode

the full duration of time spent asleep (e.g. 8 hours).

NREM sleep

- takes up around 80% of a sleep episode of typical adult.

- characterised by a progressive decline in physiological activity.

- consists of three distinct stages.

- generally thought to support body recovery.

REM sleep

- takes up around 20% of a sleep episode of typical adult.

- characterised by quick darting of the eyes behind closed eyelids.

- skeletal muscles are in a paralysed like state.

- high brain activity.

- when we experience dreaming.

- generally thought to support memory and strengthening neural connections.

Sleep Cycle

an approximately 90-minute-period that repeats during a sleep episode in which an individual progresses through stages of REM and NREM sleep.

Electroencephalography (EEG)

detect, amplify and record the electrical activity of the brains surface.

Electromyography (EMG)

device used to detect, amplify and record the electrical activity of skeletal muscles.

Electro-oculargraphy (EOG)

device used to detect, amplify and record the electrical activity of the eye muscles that control eye movements.

sleep diary

a self-report record of an individual's sleep and waking time activities.

video monitoring

Sleep laboratories usually record externally observable physiological responses on a video camera.

circadian rhythm

any biological changes or activities that repeat every 24 hours e.g. the sleep-wake cycle

Ultradian rhythm

any biological changes or activities that repeat more than once every 24 hours e.g. sleep cycle, heartbeat, breathing

Melatonin

a hormone that is involved in the initiation of sleep and in the regulation of the sleep-wake cycle.

pineal gland

secretes melatonin

suprachiasmatic nucleus (SCN)

a pair of cell clusters in the hypothalamus that controls circadian rhythm. In response to light, the SCN causes the pineal gland to adjust melatonin production, thus modifying our feelings of drowsiness/alertness.

hypnogram

A graphic depiction of a person's progress through the stages of sleep over the course of a night.