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Chapter 5: Variations in Consciousness

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  1. Chapter 5: Variations in Consciousness

  2. The Nature of Consciousness • What is consciousness? • Your awareness of external events • your awareness of internal sensations • your awareness of yourself as a unique being having experiences • your awareness of your thoughts about these experiences • The critical element in consciousness is awareness!

  3. Variations in Consciousness • Levels of awareness • Consciousness is not all-or-none • Awake • Sleep • Anesthesia • Coma • Persistent Vegetative State • Death

  4. Definitions of Death • As little as 50 years ago, people were considered “dead” when their heartbeat & breathing stopped. • Brain Death • total unawareness of externally applied stimuli • no movements or breathing during a period of at least one hour • no reflexes • flat EEG (no brain waves)

  5. The Electroencephalograph:A Physiological Index of Consciousness • EEG – monitoring of brain electrical activity • Brain-waves • Amplitude (height) • Frequency (cycles per second) • Beta (13-24 cps) • Alpha (8-12 cps) • Theta (4-7 cps) • Delta (<4 cps)

  6. Biological Rhythms and Sleep • Circadian Rhythms – 24 hr biological cycles • Regulation of sleep/other body functions • Physiological pathway of the biological clock: • Light levels  retina  suprachiasmatic nucleus of hypothalamus  pineal gland  secretion of melatonin • Melatonin and circadian rhythms

  7. Sleep/Waking Research • Instruments: • Electroencephalograph – brain electrical activity • Electromyograph – muscle activity • Electrooculograph – eye movements • Other bodily functions also observed

  8. Sleep Stages: Cycling Through Sleep • Stage 1: brief, transitional (1-7 minutes) • alpha  theta • hypnic jerks • Stage 2: sleep spindles (10-25 minutes) • Stages 3 & 4: slow-wave sleep (30 minutes) • Stage 5: REM, EEG similar to awake, vivid dreaming (first a few minutes, then longer) • Developmental differences in REM sleep

  9. Fig. 5-6, p. 182

  10. Figure 5.5 An overview of the cycle of sleep

  11. The Neural Bases of Sleep • Brain Structures: • Ascending reticular activating system • Pons, medulla, thalamus, hypothalamus, limbic system • Neurotransmitters: • Acetylcholine and serotonin • Also norepinephrine, dopamine, and GABA

  12. Why Do We Sleep? • Hypothesis 1: • Sleep evolved to conserve organisms’ energy • Hypothesis 2: • Immobilization during sleep is adaptive because it reduces danger • Hypothesis 3: • Sleep helps animals to restore energy and other bodily resources

  13. Sleep Deprivation • Complete deprivation • 3 or 4 days max • Partial deprivation or sleep restriction • impaired attention, reaction time, coordination, and decision making • accidents: Chernobyl, Exxon Valdez • Selective deprivation • REM and slow-wave sleep: rebound effect

  14. Figure 5.9 Effect of sleep deprivation on cognitive performance

  15. Sleep Problems • Insomnia – difficulty falling or staying asleep • Narcolepsy – falling asleep uncontrollably • Sleep Apnea – reflexive gasping for air that awakens • Nightmares – anxiety arousing dreams - REM • Night Terrors – intense arousal and panic - NREM • Somnambulism – sleepwalking

  16. Types of Insomnia • Three “flavors” of insomnia • Difficulty falling asleep • No problem falling asleep but difficulty staying asleep (many awakenings) • Waking up too early • Three basic types of Insomnia • Transient insomnia - lasting for a few nights • Short-term insomnia - two or three weeks of poor sleep • Chronic insomnia - poor sleep that last three weeks or longer

  17. Figure 5.12 Sleep problems and the cycle of sleep

  18. Dreams and Dreaming:Content and Significance • Dreams – mental experiences during sleep • Content usually familiar • Common themes • Waking life spillover – day residue • Western vs. Non-Western interpretations

  19. Figure 5.14 Three theories of dreaming

  20. Hypnosis: Altered State of Consciousness or Role Playing? • Hypnosis = a systematic procedure that increases suggestibility • Theories of hypnosis • Role Playing (Barber & Spanos) • people act out the “role” of hypnotized subjects and do what they think hypnotized people should do • Altered State of Consciousness (Hilgard) • people dissociate by splitting awareness into two separate simultaneous streams of awareness • Hypnotic susceptibility: individual differences • Effects produced through hypnosis: • Anesthesia • Sensory distortions and hallucinations • Disinhibition • Posthypnotic suggestions and amnesia

  21. Meditation • Meditation = practices that train attention to heighten awareness and bring mental processes under greater voluntary control • Yoga, Zen, transcendental meditation (TM) • Potential physiological benefits • Similar to effective relaxation procedures

  22. Psychoactive drugs • Narcotics (opiates) – pain relieving • Sedatives – sleep inducing • Stimulants – increase CNS activity • Hallucinogens – distort sensory and perceptual experience • Cannabis – produce mild, relaxed euphoria • Alcohol – produces relaxed euphoria, decreases in inhibitions • MDMA – produces a warm, friendly euphoria

  23. Table 5.3 Psychoactive Drugs: Tolerance, Dependence, Potential for Fatal Overdose, and Health Risks