Sleep and Dreaming

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Sleep and Dreaming
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Sleep
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Sleep observation

• EEG
• EOG
• EMG

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EEG

• electroencephalogram
• like recording crowd sounds at Fenway from a
  microphone suspended from a helicopter

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EOG

• electrooculogram
• records eye movements

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EMG

• electromyogram
• records peripheral muscle movements

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A Nights Sleep

• in the sleep lab
• put on jammies
• hop in bed
• have electrodes pasted to skull (EEG), chin
  (EMG), around eyes (EOG)
• cuddle up with Teddy and lights out

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Stage 1

• EEG recordings change from Beta to Alpha

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Beta

• 13-30 Hertz (Hz)
• low amplitude,
• high frequency,
• desynchronized (a chorus of thousands singing
  different tunes)

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Alpha

• 8-12 Hz
• high amplitude
• low frequency
• synchronized (Omm)

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Beta vs. Alpha waves

• Beta awake and alert
• Alpha relaxed

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Stage 1

• transition between sleeping and waking
• eyelids slowly open and close
• eyes roll up and down

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Beta
Alpha
Theta
drowsy
awake, alert
Stage 1
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Theta

• 3.5-7.5 Hz

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Stage 1

• Theta

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10 minutes later...
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Stage 2

• person sleeping soundly
• if awakened, deny they were asleep

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Stage 2 EEG

• Theta
• Sleep spindles (12-14 Hz)
• K complexes

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Stage 2 EEG

• spindle

K complex
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15 minutes later...
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Stage 3

• appearance of Delta waves (20-50)
• lt3.5 Hz

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Stage 3 EEG

• Delta waves

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Stage 4

• gt50 Delta

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REM sleep

• EEG desynchronizes, looks like Stage 1
• eyes dart rapidly back and forth under lids
• EMG goes silent
• Loss of muscle tonus, with brief occasional
  twitching of hands and feet

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REM sleep

• beta waves

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Function of Sleep

• adaptation
• restoration

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Adaptation

• over 50 of variability in sleep time accounted
  for by size, vulnerability

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Restoration

• physical
• mental

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Restoration

• sleep deprivation should produce signs of
  physical, mental deterioration
• Peter Tripp vs. Randy Gardner
• Tripp in late 30s Gardner a teenager

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Human Sleep Deprivation studies

• no real effects when physical activity minimized
• sleepiness greates at night peaks at 48 hours
  and doesnt increase further

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Animal deprivation studies

• rats dunked in water died of massive internal
  damage
• ulcers
• massive internal hemorrhage
• STRESS?

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Stage 4 sleep deprivation(in humans)

• rebound
• muscle pains, irritability, etc.
• in Stage 3 secretion of growth hormone and
  synthesis of new proteins

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REM deprivation (humans)

• rebound
• may have effects on mental health

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Depression studies

• depressed patients spend more time in REM
• anti-depressants inhibit REM
• sleep loss may lift depression

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REM and consolidation

• early 70s REM deprivation interfers with memory
  of emotionally loaded words

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REM and emotional procesing

• Circumcision in S. Pacific Islandersfilm
  produces anxiety which drops on subsequent
  viewings
• REM deprivation interfers with drop in anxiety
• dream content between showings reflects film
  content

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REM and depression

• normal people unrealistic about negative events
• depressed people too realistic
• interrupting processing of negative events by
  alleviate depression