Module 1.5abc-Unit 1: Sleep, Consciousness, Stages, Disorders, and Dreams

consciousness

our subjective awareness of ourselves and our environment

cognitive neuroscience

the interdisciplinary study of the brain activity linked with cognition (thinking, knowing, remembering, and communicating).

dual processing

the principle that information is often simultaneously processed on separate conscious and unconscious tracks.

blindsight

a condition in which a person can respond to a visual stimulus without consciously experiencing it.

parallel processing

processing multiple aspects of a stimulus or problem simultaneously.

sequential processing

processing one aspect of a stimulus or problem at a time; generally used to process new information or to solve difficult problems.

sleep

a periodic, natural loss of consciousness—as distinct from unconsciousness resulting from a coma, general anesthesia, or hibernation.

circadian rythym

our biological clock; regular bodily rhythms (for example, of temperature and wakefulness) that occur on a 24-hour cycle.

REM sleep

rapid eye movement sleep; a recurring sleep stage during which vivid dreams commonly occur. Also known as paradoxical sleep, because the muscles are relaxed (except for minor eye twitches) but other body systems are active. (Sometimes called R sleep.)

alpha waves

the relatively slow brain waves of a relaxed, awake state.

NREM sleep

non-rapid eye movement sleep; encompasses all sleep stages except for REM sleep.

hallucinations

false sensory experiences, such as seeing something in the absence of an external visual stimulus.

hypnagogic sensations

bizarre experiences, such as jerking or a feeling of falling or floating weightlessly, while transitioning to sleep. (Also called hypnic sensations.)

delta waves

the large, slow brainwaves associated with deep sleep.

suprachiasmatic nucleus (SCN)

a pair of cell clusters in the hypothalamus that controls circadian rhythm. In response to light, it adjusts melatonin production, thus modifying our feelings of sleepiness.

insomnia

recurring problems in falling or staying asleep.

narcolepsy

a sleep disorder characterized by uncontrollable sleep attacks. The affected person may lapse directly into REM sleep, often at inopportune times.

sleep apnea

a sleep disorder characterized by temporary cessations of breathing during sleep and repeated momentary awakenings.

REM sleep behavior disorder

a sleep disorder in which normal REM paralysis does not occur; instead, twitching, talking, or even kicking or punching may occur, often acting out one’s dream.

dream

a sequence of images, emotions, and thoughts passing through a sleeping person’s mind.

REM rebound

the tendency for REM sleep to increase following REM sleep deprivation.