Sleep, Biological Rhythms, and Psychoactive Substances: Study Guide for Psychology Exam

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Biological Rhythms and Sleep

Biological Rhythms

Biological rhythms are regular, cyclical changes in biological processes and behaviors that occur over time. These rhythms are essential for maintaining homeostasis and regulating bodily functions.

Circadian rhythms: These are 24-hour cycles that regulate sleep-wake patterns, hormone release, and other bodily functions. The body's 'biological clock' is located in the suprachiasmatic nucleus (SCN) of the hypothalamus.
Endogenous cycles: Internal cycles that persist even without external cues, such as light or temperature.
SCN and melatonin: The SCN controls the release of melatonin, a hormone that promotes sleep. Disruptions in the SCN can lead to internal desynchronization, affecting sleep and alertness.

Examples and Applications

Jet lag: A common example of circadian rhythm disruption due to rapid travel across time zones.
Shift work: Working night shifts can desynchronize biological rhythms, leading to sleep problems.

Moods and Long-Term Rhythms

Premenstrual and Affective Disorders

Some psychological disorders are linked to biological rhythms and hormonal changes.

Premenstrual dysphoric disorder (PMDD): Severe mood symptoms related to the menstrual cycle.
PMS (Premenstrual Syndrome): Includes physical and emotional symptoms; myths and facts are discussed in the course readings.
Seasonal Affective Disorder (SAD): A mood disorder characterized by depression that occurs at a specific time of year, usually winter.

Stages of Sleep

The Three Stages of Sleep

Sleep is divided into several stages, each characterized by distinct brain wave patterns and physiological changes.

NREM (Non-Rapid Eye Movement) Sleep: Includes stages 1-3, with progressively deeper sleep. Brain waves slow down, and physiological activity decreases.
REM (Rapid Eye Movement) Sleep: Characterized by rapid eye movements, vivid dreaming, and increased brain activity. Most dreams occur during REM sleep.

Brain Wave Patterns

Awake states: Dominated by beta and alpha waves.
Sleep states: Characterized by theta and delta waves. These waves are slower and indicate deeper stages of sleep.

Physiological Changes During Sleep

Slowing of heart rate
Decreased breathing rate
Reduced muscle tone

Sleep Deprivation

Consequences include impaired cognitive function, mood disturbances, and increased risk of health problems.

Sleep Disorders

Common Sleep Disorders

Insomnia: Difficulty falling or staying asleep.
Sleep apnea: Breathing interruptions during sleep.
Narcolepsy: Sudden, uncontrollable episodes of sleep.

Dream Theories

Functions and Theories of Dreaming

Problem-focused approach: Dreams help solve problems and process emotions.
Cognitive approach: Dreams reflect cognitive development and information processing.

Activation-Synthesis Theory

Dreams result from the brain's attempt to make sense of random neural activity during sleep.

Psychoactive Substances

Drugs and Their Effects on the Nervous System

Psychoactive substances alter brain function, mood, and behavior. They are classified based on their effects.

Stimulants: Increase nervous system activity (e.g., caffeine, amphetamines).
Depressants: Decrease nervous system activity (e.g., alcohol, benzodiazepines).

Recognizing Drug Effects

Symptoms, behavior, and physiological signs can help identify the type of drug used.
Some drugs can lead to overdose and possibly death.

Short Answer Essay Topics

Stimulant vs. Depressant Substances

Define and compare the effects of stimulants and depressants on the nervous system.
List examples and describe their impact on behavior and physiology.

Stages of Sleep

Describe the stages of sleep, changes in brain and body, and associated brain wave patterns.
Discuss time frames for moving through sleep stages and the differences between REM and NREM sleep.

Brain Waves

Define and describe alpha and beta waves in awake states.
Explain theta and delta waves in sleep states.

Table: Sleep Stages and Brain Waves

Stage	Brain Waves	Key Features
Awake	Beta, Alpha	Alertness, relaxed wakefulness
NREM Stage 1	Theta	Light sleep, muscle relaxation
NREM Stage 2	Theta, Sleep spindles	Deeper sleep, body temperature drops
NREM Stage 3	Delta	Deep sleep, slow heart rate
REM	Fast, mixed frequency	Dreaming, rapid eye movement

Key Equations and Concepts

Circadian rhythm period:
Sleep cycle duration:

Additional info:

Some content inferred from context and standard psychology curriculum, such as definitions and examples of sleep disorders and drug classifications.
Table entries and equations are based on typical textbook information for introductory psychology courses.