Psych U4

Circadian Rhythm

The body's internal biological clock that follows an approximately 24-hour cycle and regulates sleep, wakefulness, and other body functions.

REM Sleep

Rapid Eye Movement sleep. A sleep stage characterized by rapid eye movements, vivid dreaming, and temporary muscle paralysis.

Alpha Waves

Brain waves associated with a relaxed but awake state, often occurring when your eyes are closed and you are preparing to fall asleep.

NREM Sleep

Non-Rapid Eye Movement sleep. Includes all stages of sleep that are not REM sleep.

Hallucinations

Sensory experiences, such as seeing or hearing something, that are not actually happening.

Hypnagogic Sensations

Strange sensations that occur while falling asleep, such as feeling like you are falling or suddenly jerking awake.

Sleep Spindles

Short bursts of rapid brain-wave activity during Stage 2 sleep that are associated with memory processing and learning.

Delta Waves

Slow brain waves associated with deep sleep, especially NREM Stage 3.

Suprachiasmatic Nucleus (SCN)

A group of cells in the hypothalamus that controls the body's circadian rhythm using information about light.

Melatonin

A hormone produced by the pineal gland that helps regulate sleepiness and the sleep-wake cycle. Darkness increases its production.

Stage 1 NREM

Light sleep, transition between wakefulness and sleep. Hypnagogic sensations may occur.

Stage 2 NREM

Deeper sleep. Sleep spindles and K-complexes occur.

Stage 3 NREM

Deep sleep characterized by delta waves. It is difficult to wake someone during this stage.

REM Sleep

Vivid dreaming, rapid eye movements, and temporary muscle paralysis. Brain activity resembles wakefulness.

What happens during a normal sleep cycle?

The body cycles through NREM stages and REM sleep approximately every 90 minutes. REM periods generally become longer later in the night.

Insomnia

A sleep disorder involving difficulty falling asleep, staying asleep, or getting restful sleep.

Narcolepsy

A sleep disorder involving uncontrollable sleep attacks and sometimes suddenly entering REM sleep.

Sleep Apnea

A disorder in which breathing repeatedly stops and starts during sleep, causing disrupted sleep.

REM Sleep Behavior Disorder

A disorder in which the normal muscle paralysis during REM sleep does not work properly, allowing someone to physically act out dreams.

REM Rebound

An increase in REM sleep after someone has been deprived of REM sleep.

Protective

Sleep may have helped our ancestors stay safe by keeping them inactive during dangerous times.

Recuperation

Sleep allows the body and brain to recover, repair tissue, and restore energy.

Memory and Learning

Sleep helps process information, strengthen memories, and improve learning.

Growth

Sleep supports physical development through the release of growth hormones.

Brain Development and Restoration

Sleep supports healthy brain functioning and helps maintain and restore neural connections.

Wish Fulfillment Theory

Dreams represent unconscious wishes, desires, and thoughts that people may not express while awake.

Information-Processing Theory

Dreams help the brain process, organize, and store information and memories from the day.

Physiological Function Theory

Dreaming helps the brain develop and maintain neural pathways needed for proper brain functioning.

Activation-Synthesis Theory

Dreams happen when the brain tries to make sense of random neural activity during sleep by creating a story.

Cognitive Development Theory

Dreams reflect a person's knowledge, experiences, understanding, and level of brain development.

Psychoactive Drugs

Chemicals that change brain functioning, perception, consciousness, mood, or behavior.

Substance Use Disorder

A condition in which someone continues using a substance despite harmful consequences and difficulty controlling their use.

Depressants

Drugs that slow down activity in the central nervous system.

Alcohol

Depressant. Slows nervous system activity and affects judgment, coordination, reaction time, and inhibitions.

Barbiturates

Depressants that reduce central nervous system activity. Can reduce anxiety but impair memory and judgment.

Opioids

Depress nervous system activity and temporarily reduce pain and anxiety. Can cause dependence and dangerous respiratory depression.

Heroin

An opioid depressant. Produces euphoria and pain relief by activating opioid receptors and can lead to physical dependence.

Stimulants

Drugs that increase central nervous system activity, alertness, and energy.

Caffeine

Stimulant. Increases alertness and reduces feelings of tiredness by blocking adenosine receptors.

Nicotine

Stimulant. Increases alertness and activates reward pathways. Highly addictive and can cause withdrawal.

Cocaine

Stimulant. Produces intense euphoria by interfering with the reuptake of dopamine, serotonin, and norepinephrine.

Methamphetamine

Powerful stimulant. Causes a large release of dopamine, producing intense energy and euphoria. Long-term use can damage brain functioning.

Ecstasy (MDMA)

Has stimulant and mild hallucinogenic effects. Causes a large release of serotonin and affects dopamine, increasing feelings of pleasure and emotional closeness.

Hallucinogens

Drugs that alter perception and can cause someone to experience sensations or images that are not actually present.

LSD

Hallucinogen. Changes perception, thoughts, and sensory experiences and can cause visual hallucinations.

Marijuana (Cannabis)

Can alter perception, time awareness, memory, coordination, and mood. THC is its primary psychoactive chemical. It is commonly classified as a hallucinogen in introductory psychology.

Tolerance

When the body becomes accustomed to a drug, requiring more of it to achieve the same effect.

Withdrawal

Physical or psychological symptoms that occur when someone stops or reduces drug use after becoming dependent.

Physical Dependence

When the body adapts to a drug and experiences physical withdrawal symptoms when the drug is removed.

Psychological Dependence

When someone feels mentally or emotionally that they need a drug to function or feel normal.

Addiction

Compulsive substance use that continues despite harmful consequences.

Near-Death Experience

An altered state of consciousness that some people report experiencing when close to death, sometimes involving bright lights, tunnels, or out-of-body sensations.

Altered State of Consciousness

A state of awareness that differs from normal waking consciousness, such as dreaming, hypnosis, or intoxication.