memory and cognition

NREM-1

The initial stage of non-rapid eye movement sleep characterized by slow breathing, irregular brain waves, lack of awareness, and potential hallucinations.

Hallucinations

Sensory experiences that occur without an external visual stimulus, often described as hypnagogic.

Hypnagogic sensation

A bizarre experience like feeling weightless, occurring during the transition to NREM-1.

Alpha waves

Slow brain waves associated with a state of relaxation and awareness.

Delta waves

Long, slow brain waves that occur during deep sleep.

Theta waves

Brain waves present during light sleep.

Sleep spindles

Bursts of brain activity that occur during NREM-2.

NREM sleep

Non-rapid eye movement sleep, which includes all stages of sleep except REM.

Insomnia

A sleep disorder characterized by difficulty falling asleep or staying asleep.

Narcolepsy

A sleep disorder marked by uncontrollable sleep attacks that can lead the person directly into REM sleep.

Sleep apnea

A condition often found in overweight individuals, causing temporary cessation of breathing during sleep.

Night terrors

Disruptive episodes during NREM-3, where individuals wake up without recalling the event.

Dream

A sequence of images, emotions, and thoughts that occur in a person's mind during REM sleep.

Manifest content

The storyline of a dream, according to Freud.

Latent content

The underlying meaning of a dream.

Methamphetamine

A powerful stimulant drug that accelerates body functions and affects mood.

Ecstasy (MDMA)

A synthetic stimulant and mild hallucinogen that produces euphoria by releasing dopamine and serotonin.

Caffeine

A central nervous system stimulant found in coffee and other products.

Circadian rhythm

The biological 24-hour cycle that regulates physiological processes.

Suprachiasmatic Nucleus

A cluster of neurons in the hypothalamus that regulates circadian rhythms and melatonin production.

Melatonin

A hormone associated with the sleep/wake cycle, released during darkness.

Activation synthesis theory

The hypothesis that dreams are the brain's attempt to synthesize random neural activity.

REM rebound

The phenomenon where REM sleep increases following periods of REM sleep deprivation.

Psychoactive drugs

Chemicals that alter perception and mood.

Physical dependence

A physiological need for a drug that results in unpleasant withdrawal symptoms.

Psychological dependence

The need to use a drug to relieve negative emotions.

Addiction

The compulsive use of a drug despite harmful consequences.

Opiates

Drugs that depress neural activity, reducing pain and anxiety, including morphine and heroin.