Key points in this topic.
● sleep as a regular and naturally occurring altered state of consciousness that follows a circadian rhythm and involves the ultradian rhythms of REM and NREM Stages 1–4 sleep excluding corresponding brain wave patterns and physiological responses for each stage
● theories of the purpose and function of sleep (REM and NREM) including restoration theory and evolutionary (circadian) theory
● the differences in sleep across the lifespan and how these can be explained with reference to the total amount of sleep and changes in a typical pattern of sleep (proportion of REM and NREM).
Grivas J, Letch N 2017, Psychology VCE Units 3&4 Seventh Edition, Jacaranda.
Arousal threshold - the term “arousal threshold” in reference to the respiratory neuromechanical drive or pressure that is present immediately prior to a clinically defined electroencephalography (EEG) (cortical) arousal.
Biological clock - an innate mechanism that controls the physiological activities of an organism which change on a daily, seasonal, yearly, or other regular cycle.
Biological rhythms - periodic biological fluctuation in an organism that corresponds to, and is in response to, periodic environmental change. Examples of such change include cyclical variations in the relative position of Earth to the Sun and to the Moon and in the immediate effects of such variations—e.g., day alternating with night, high tide alternating with low tide.
Circadian rhythms - Circadian rhythms are physical, mental, and behavioral changes that follow a daily cycle.
Entrainment - occurs when rhythmic physiological or behavioral events match their period to that of an environmental oscillation. It is ultimately the interaction between circadian rhythms and the environment.
Evolutionary (circadian) theory - Evolutionary theory, also known as the adaptive theory of sleep, suggests that periods of activity and inactivity evolved as a means of conserving energy.
Hypnagogic state - Hypnagogia, also referred to as "hypnagogic hallucinations", is the experience of the transitional state from wakefulness to sleep: the hypnagogic state of consciousness, during the onset of sleep
Hypnogram - A hypnogram is a form of polysomnography; it is a graph that represents the stages of sleep as a function of time.
Hypothalamus - The hypothalamus is a portion of the brain that contains a number of small nuclei with a variety of functions. One of the most important functions of the hypothalamus is to link the nervous system to the endocrine system via the pituitary gland.
Melatonin - Melatonin is the natural hormone your body secretes that helps to maintain your wake-sleep cycle (also called biological clock).
NREM sleep - A period of sleep characterised by decreased metabolic activity, slowed breathing and heart rate, and the absence of dreaming. Non-REM sleep occurs in the first four of the five stages of the sleep cycle, followed by REM sleep, during which dreaming occurs.
Paradoxical sleep - a recurring sleep state during which dreaming occurs; a state of rapidly shifting eye movements during sleep
Perceptual disengagement - a defining characteristic of sleep
Pineal gland - a pea-sized conical mass of tissue behind the third ventricle of the brain, secreting a hormone-like substance in some mammals.
REM sleep - a kind of sleep that occurs at intervals during the night and is characterized by rapid eye movements, more dreaming and bodily movement, and faster pulse and breathing
Restoration theory - A restorative theory claims that sleep is used to repair the body including the brain. Oswald suggests that slow wave sleep is when body repair occurs and REM sleep is when the brain is repaired.
Sleep cycle - The sleep cycle is an oscillation between the slow-wave and REM phases of sleep.
Sleep episode – in interval of sleep that may be voluntary or involuntary
Sleep latency - In sleep science, sleep onset latency is the length of time that it takes to accomplish the transition from full wakefulness to sleep, normally to the lightest of the non-REM sleep stages.
Sleep onset - Sleep onset is the transition from wakefulness into sleep
Sleep paralysis - Sleep paralysis is a state, during waking up or falling asleep, in which a person is aware but unable to move or speak.
Sleep-wake cycle - a daily pattern that determines when it’s time to sleep and when it’s time to be awake.
Slow wave sleep - Slow-wave sleep (SWS), often referred to as deep sleep, consists of stage three of non-rapid eye movement sleep.
Suprachiasmatic nucleus (SCN) - each of a pair of small nuclei in the hypothalamus of the brain, above the optic chiasma, thought to be concerned with the regulation of physiological circadian rhythms
Ultradian rhythms - a recurrent period or cycle repeated throughout a 24-hour day.
Unresponsiveness – not responsive.
