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Chapter 5: Variations in Consciousness. The Nature of Consciousness  What is consciousness? Your awareness of external events your awareness of internal.

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Presentation on theme: "Chapter 5: Variations in Consciousness. The Nature of Consciousness  What is consciousness? Your awareness of external events your awareness of internal."— Presentation transcript:

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)EEG

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)

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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: 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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