Sleep and dreaming

• What are sleep cycles in psychology?


  Recurring patterns of brain activity that occur during sleep
• How many sleep cycles does a typical night's sleep consist of?

  4-6 sleep cycles
• What is the duration of a typical sleep cycle?

  About 90-120 minutes
• What are the two main types of sleep in a sleep cycle?

  - Non-REM (NREM) sleep - REM (Rapid Eye Movement) sleep
• In what order do the brain cycles through sleep stages?

  Starting with NREM and ending with REM sleep
• What is Non-REM Stage 1 sleep characterized by?

  It is the lightest stage of sleep and serves as a transition between wakefulness and sleep
• What is the typical duration of Non-REM Stage 1 sleep?

  Usually lasts 1-5 minutes
• What type of brain waves are present in Non-REM Stage 1 sleep?

  Theta waves
• What happens to muscle activity during Non-REM Stage 1 sleep?

  Muscle activity begins to slow down
• How easily can a person be awakened during Non-REM Stage 1 sleep?

  They can be easily awakened
• What are hypnic jerks associated with Non-REM Stage 1 sleep?

  Sudden muscle contractions that may occur
• What are the key characteristics of Non-REM Stage 2 sleep?

  - Duration: 20-30 minutes in early cycles - Brain waves: Sleep spindles and K-complexes - Body temperature: Begins to decrease - Heart rate: Slows down - Muscle tension: Further decreases
• What percentage of total sleep time does Non-REM Stage 2 make up in adults?

  About 50%
• What brain wave patterns are characteristic of Non-REM Stage 2 sleep?

  Sleep spindles and K-complexes
• What physiological changes occur during Non-REM Stage 3 sleep?

  Blood pressure drops, breathing slows, and muscles relax completely
• What is the duration of Non-REM Stage 3 sleep?

  Typically 20-40 minutes
• What type of brain waves are predominant in Non-REM Stage 3 sleep?

  Delta waves
• What is the arousal threshold during Non-REM Stage 3 sleep?

  Very high, making it difficult to wake someone
• What is a key function of Non-REM Stage 3 sleep?

  Critical for physical recovery and memory consolidation
• What are the key characteristics of REM sleep?

  - Timing: First occurs about 90 minutes after falling asleep - Duration: Initially short (10 minutes), lengthens in later cycles - Brain activity: Similar to waking state - Eye movements: Rapid, side-to-side movements - Muscle activity: Temporary paralysis of major voluntary muscles - Physiological changes: Increased heart rate, elevated blood pressure, irregular breathing - Function: Critical for cognitive functions like memory consolidation and emotional regulation
• What percentage of total sleep time does REM sleep typically account for in adults?

  About 20-25%
• What type of dreams occur during REM sleep?

  Most vivid and memorable dreams
• What is the relationship between REM sleep and cognitive functions?

  REM sleep is critical for memory consolidation, learning, and emotional regulation