U4: States of Consciousness

Circadian rhythm

the biological clock; regular bodily rhythms that occur on a 24-hour cycle

Alpha waves

the relatively slow brain waves of a relaxed, awake state

Beta waves

smaller and faster brain waves, typically indicating mental activity

Stage 1

light sleep

Stage 2

sleep spindles

Stage 3

delta waves

REM

describes sleep in which vivid dreams typically occur; this type of sleep increases as the night progresses while stage 4 sleep decreases

Activation synthesis model

the theory that dreams are produced when the brain attempts to make sense of random neural activity that occurs during sleep

Hypnagogic sensations

bizarre experiences, such as jerking or a feeling of falling or floating weightlessly, while transitioning to sleep

Paradoxical sleep

The type of sleep encountered during REM when internally, the brain and body are active; while externally, the body appears calm and inactive

Restorative theory of sleep

the theory that the function of sleep is to restore body and mind

REM rebound

the tendency for REM sleep to increase following REM sleep deprivation (created by repeated awakenings during REM sleep)

Miscrosleeps

brief sidesteps into sleep lasting only a few seconds

Insomnia

recurring problems in falling or staying asleep

Narcolepsy

A sleep disorder characterized by uncontrollable sleep attacks. The sufferer may lapse directly into REM sleep, often at inopportune times.

REM sleep behavior disorder

a neurological disorder in which the person does not become paralyzed during REM sleep and thus acts out dreams

Night terrors

a sleep disorder characterized by high arousal and an appearance of being terrified; unlike nightmares, night terrors occur during Stage 4 sleep, within two or three hours of falling asleep, and are seldom remembered

Somnambulism

the condition of walking or performing some other activity without awakening; also known as sleepwalking

Sleep apnea

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

Age related sleep patterns

Children & adolescents: large amounts slow-wave sleep

Sleep continuity & depth decrease with age

Psychoactive drugs

chemicals that affect the central nervous system and alter activity in the brain

Narcotics

Specific drugs that are obtainable only by prescription and are used to relieve pain

Sedatives

Sleep-inducing drugs that tend to decrease central nervous system activation and behavioral activity.

Stimulants

Drugs (such as caffeine, nicotine, and the more powerful amphetamines, cocaine, and Ecstasy) that excite neural activity and speed up body functions.

Suprachiasmatic nucleus of the hypothalamus

circadian rhythm

Pineal gland

secretes melatonin

Hallucinogens

psychedelic ("mind-manifesting") drugs, such as LSD, that distort perceptions and evoke sensory images in the absence of sensory input

Melatonin

A hormone manufactured by the pineal gland that produces sleepiness.