6 Stages of Sleep & 3 Biological Reasons for Sleep-Roller Coaster of Dreams YouTube Lecture Handouts for Andhra Pradesh PSC

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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

Image of Waking Consciousness And Altered Consciousness

Image of Waking Consciousness and Altered Consciousness

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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

Image of Biological Basis of Sleep

Image of Biological Basis of Sleep

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Night Roller-Coaster

Image of Night Roller Coaster

Image of Night Roller Coaster

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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 (4-7Hz)

  • No K-Complex or Sleep Spindles

  • EEG – Low voltage (amplitude) implies high frequency

  • EMG – Lower than Stage W

Image of Stage - 1

Image of Stage - 1

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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

Image of Sleep Spindles And K Complexes

Image of Sleep Spindles and K Complexes

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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 (<0.10sec)

  • 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 - 1

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Rapid Eye Movement Sleep Image - 2

Rapid Eye Movement Sleep Image - 2

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Rapid Eye Movement Sleep Image - 3

Rapid Eye Movement Sleep Image - 3

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Recommendations - American Academy of Sleep Medicine (AASM)

  • REM → R

  • NREM → N

  • Wakefulness → W

  • Stage 3 & 4 → N3

  • Now, W, R, N1, N2, and N3