Lecture Notes: Sleep Stages and Brain Waves

Key Points

Brain Waves

• Don't worry about specific names (beta, theta, etc.)
• Understand the pattern change:
  • Awake: Brain waves are zigzaggy and tiny
  • Relaxing/Deeper Sleep: Waves slow down and get larger in amplitude
  • REM Sleep: Resembles awake brain activity

Sleep Stages

• N-REM Sleep (Non-REM Sleep)
  • Stage 1: Light sleep
  • Stage 2: Deeper
  • Stage 3 (Slow Wave Sleep): Deepest sleep
  • Stage 4 sometimes mentioned, but not exact – focus on 3 main stages
• REM Sleep (Rapid Eye Movement Sleep)
  • Brain activity similar to being awake
  • Dreams occur here
  • Brain is active but the body is mostly paralyzed

Remember

• Sleep cycle: About every 90 minutes
  • Not every stage repeats consistently in each cycle
  • First half of the night: More deep sleep (Stage 3)
  • Second half of the night: More REM sleep, preparing body to wake up
• Waking up: Often from a dream due to more time spent in REM in the latter half of sleep

Important Concepts

• Amplitude: Height of the brain wave
• Brain Activity: More during REM sleep
• Paralysis in REM Sleep: Body is paralyzed while brain is active
• Cycle Patterns: Deep sleep early, more REM later

Clarifications

• 3 main [N-REM] stages + 1 REM stage
• Brain waves change from tiny and zigzaggy (awake) to big and slow (deep sleep)
• REM looks like awake activity but involves paralysis and dreaming

Practical Notes

• Test: Open book/open notes
• Focus on understanding the stages rather than memorizing brain wave names