6 Stages of Sleep & 3 Biological Reasons for Sleep - Roller Coaster of Dreams YouTube Lecture Handouts for NET, IAS, State-SET (KSET, WBSET, MPSET, etc.), GATE, CUET, Olympiads etc.
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6 Stages of Sleep & 3 Biological Reasons for Sleep - Roller Coaster of Dreams
CONSCIOUSNESS
Sensations & perceptions of external events
+
Self-awareness of mental events
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
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 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
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)
Recommendations - American Academy of Sleep Medicine (AASM)
- REM ⇾ R
- NREM ⇾ N
- Wakefulness ⇾ W
- Stage 3 & 4 ⇾
- Now, W, R, , and
✍ Manishika