6 Stages of Sleep & 3 Biological Reasons for Sleep-Roller Coaster of Dreams YouTube Lecture Handouts for ICMR NET

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6 Stages of Sleep & 3 Biological Reasons for Sleep - Roller Coaster of Dreams

CONSCIOUSNESS

Sensations & perceptions of external events

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Self-awareness of mental events

Waking Consciousness and Altered Consciousness

Causes of Altered State of Consciousness

  • Sensory Overload
  • Monotonous Stimulation
  • Unusual Physical Conditions
  • Restricted Sensory Input

SLEEP

Micro-sleep to Macro-accidents

It is necessity not luxury

Biological Basis of Sleep

Biological Basis of Sleep

Night Roller-Coaster

Night Roller Coaster

EEG & EMG Patterns

β (beta) > 13 Hz

13 Hz ⩾ α (alpha) ⩾ 8 Hz

8 Hz > θ (theta) ⩾ 4 Hz

4 Hz > δ (delta)

EMG > 0.5 sec ⇾ NREM Sleep

Stage W

  • Waking Stage
  • EMG – High tonic
  • EEG – low voltage (alpha and beta waves)

STAGE 1

  • Light Sleep
  • Irregular Breathing
  • Muscles relax
  • Reflex muscle twitch (hypnic jerk) / Positive Myoclonus
  • Alpha waves (8 - 13 Hz) to Theta Waves (4 - 7 Hz)
  • No K-Complex or Sleep Spindles
  • EEG – Low voltage (amplitude) implies high frequency
  • EMG – Lower than Stage W
Stage - 1

STAGE 2

  • Sleep Spindles (within 4 minutes – person sleeps) – 12 - 14 Hz
  • K-Complex (< 3 minute low voltage)
  • EMG – Muscle activity decrease
  • 45 - 55 % of total sleep
Sleep Spindles and K Complexes

Stage 3

  • Delta Waves appear (large and slow) – 0.5 - 2 Hz
  • Parasomnia, Night terror, Sleepwalking occur
  • No eye movements
  • EOG - High voltage slow wave activity
  • EMG – Active but with very low levels

Stage 4

  • Slow Wave Sleep (SWS)
  • Delta waves
  • Deepest level of normal sleep
  • EOG - High voltage slow wave activity
  • EMG – Active but with very low levels
  • Growth hormones are released at peak

REM

  • 20 - 25 % of total sleep & Most memorable dreams
  • EEG – rapid low voltage, mixed frequency
  • Descending muscle atonia
  • Sawtooth waves – Notched Waves – Theta Range
  • EMG – Lowest Level, Phasic Twitches (< 0.10 sec)
  • EOG – burst of eye movement, increase as sleep progress
  • Rare Delta waves, Alpha waves more prominent than Stage 1
  • Excessive beta waves (not confuse with sleep spindle)
  • Few K complex (if > 3 minutes)
Rapid Eye Movement Sleep Image - 1
Rapid Eye Movement Sleep Image - 2
Rapid Eye Movement Sleep Image - 3

Recommendations - American Academy of Sleep Medicine (AASM)

  • REM ⇾ R
  • NREM ⇾ N
  • Wakefulness ⇾ W
  • Stage 3 & 4 ⇾
  • Now, W, R, , and

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