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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)


7 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

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

9 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

10 Fig. 5-6, p. 182

11 Figure 5.5 An overview of the cycle of sleep

12 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

13 Why Do We Sleep? Hypothesis 1: Hypothesis 2: Hypothesis 3:
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

14 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

15 Figure 5.9 Effect of sleep deprivation on cognitive performance

16 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

17 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

18 Figure 5.12 Sleep problems and the cycle of sleep

19 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

20 Figure 5.14 Three theories of dreaming

21 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

22 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

23 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

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

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