Conciousness

Sleep

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

Circadian rhythm

regular bodily rhythms that occur on a 24-hour cycle

REM sleep

a recurring sleep stage during which vivid dreams commonly occur

NREM sleep

A lower quality, encompasses all sleep stages except for REM sleep

NREM-1

transition from wakefulness to sleep

NREM-2

deep relaxation, lasting 30-60 minutes

NREM-3

deep sleep, or slow-wave sleep, lasts about 20-40 minutes

Hallucinations

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

Hypnagogic sensations

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

Insomnia

recurring problems in falling or staying asleep

Narcolepsy

a sleep disorder characterized by uncontrollable sleep attacks

Sleep apnea

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

Somnambulism

a sleep disorder characterized by engaging in complex behaviors while still asleep

REM sleep behavior disorder (RBD)

a sleep disorder characterized by the physical acting out of dreams during REM sleep

Dreams

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

Activation-synthesis theory

a neurobiological explanation for how dreams are formed

Consolidation theory

suggests that dreaming is the result of the brain consolidating memories during sleep

Psychoactive drugs

a chemical substance that alters perceptions and moods

Substance use disorder

a disorder characterized by continued substance craving and use despite significant life disruption and/or physical risk

Tolerance

the diminishing effect with regular use of the same dose of a drug, requiring the user to take larger and larger doses before experiencing the drug's effect

Withdrawal

the discomfort and distress that follow discontinuing an addictive drug or behavior

Depressants

drugs that reduce neural activity and slow body functions (alcohol, barbiturates, opiates)

Alcohol use disorder

alcohol use marked by tolerance, withdrawal, and a drive to continue problematic use

Opiates

opium and its derivatives, such as morphine and heroin; depress neural activity, temporarily lessening pain and anxiety

Stimulants

drugs that excite neural activity and speed up body functions

Caffeine

a stimulant that speeds up the CNS, stimulating the brain, elevating mood, and postponing fatigue

Cocaine

a powerful and addictive stimulant derived from the coca plant; produces temporarily increased alertness and euphoria

Hallucinogens

psychedelic drugs that distort perceptions and evoke sensory images in the absence of sensory input

THC

the major active ingredient in marijuana; triggers a variety of effects, including mild hallucinations