Chapter 5 Consciousness

1. Chapter 5Consciousness

2. Consciousness • Awareness of ourselves and our environment: • Subjective: own conscious experiences • Selective attention: ability to focus awareness on a single stimulus • Divided attention: different stimuli at the same time.

3. Consciousness • Awareness of ourselves and our environment: • Stream of consciousness: flow of thoughts, feelings, and sensations • Many levels of consciousness

4. Sleep • A nonwaking state of consciousness characterized by minimal physical movement and responsiveness to one’s surroundings.

5. Circadian Rhythms • The behavioral cycle of sleep and wakefulness that we naturally follow throughout our lives • Circadian rhythms correspond to physiological changes, such as body temperature, blood pressure, and hormone levels.

6. Circadian Rhythms • Sleep-wakefulness cycles • A small area of the hypothalamus known as the suprachiasmatic nucleus and the hormone melatonin, produced by the pineal gland, appear to be crucial in readjusting the body’s sleep-wake cycle.

7. Circadian Rhythms Jet lag • The severity of this jet lag depends on whether you fly westward or eastward. • When flying westward your regular sleep cycle is pushed back five hours (a phase delay). The jet lag resulting from such east-west travel is easier to adjust to—and thus, less severe—than eastward-induced jet lag. • When flying eastward your day is being shortened (a phase advance), which is not only farther away from your natural 24-hour sleep-wake cycle but also is inconsistent with people’s day-stretching habits.

8. EEG Brain Wave Patterns—NREM Sleep

9. EEG Brain Wave Patterns—REM Sleep

10. Stages of Sleep • Stage:1 hypnogogic state: transition between wakefulness and sleep • myoclonic jerk; hypnogogic hallucinations • Stage 2: lasts about 20 minutes and is characterized by sleep spindles • Stage 3: slow-wave sleep; brain waves higher in amplitude and slower in frequency • Stage 4: delta waves much more pronounced • REM (rapid eye movement) sleep: “Active sleep” completes the sleep cycle.

11. The First 90 Minutes of Sleep

12. Why We Sleep • Why do we sleep? • Body needs sleep and will malfunction without a sufficient amount • Restorative theory: • Sleep allows the body to restore itself following the rigors of daily activity. • Safety/conservation theory: • It prevents us from moving about and being injured. • It conserves energy. • We honestly don’t know why we sleep.

13. Sleep Deprivation • Effects of Sleep Loss • fatigue • impaired concentration • immune suppression • irritability • slowed performance • accidents • planes • autos and trucks

14. Sleep Deprivation Accident frequency Less sleep, more accidents More sleep, fewer accidents 2,800 2,700 4,200 2,600 4000 2,500 3,800 2,400 3,600 Spring time change (hour sleep loss) Fall time change (hour sleep gained) Monday after time change Monday before time change

15. Sleep Habits Vary by Age • Newborns sleep about 16 hours • Children average between 9 and 12 hours • Adolescents average about 7.5 hours. • Newborns and young children have the highest percentage of REM sleep. Many sleep experts believe that the heightened brain activity during REM sleep in the young promotes the development of new neural pathways.

16. Sleep Habits Vary by Age • In adulthood, both quantity & quality of sleep decrease with age. • Less time is spent in slow-wave sleep. • There is more stage 1 sleep and more awakenings during the night. • The percentage of REM sleep only diminishes in later life.

17. Sleep Habits Vary Individually • Morning people (25%) wake up early, with a good deal of energy and alertness, but are ready to retire before 10:00 p.m. • Night people (25%) stay up much later and have a hard time getting up early in the morning. • This different sleep pattern appears to be related to differences in circadian body temperatures. • Morning persons’ body temperatures rise quickly rise upon awakening. The body temperature of night persons rises gradually and peaks later.

18. Sleep Habits Vary Culturally • People in industrialized settings sleep less. • This may have to do with work. • Electricity also extends the time people can be active and productive.

19. REM Sleep • REM phase of sleep is paradoxical. • Brain waves are active. • Body is paralyzed. • People dream during REM. • Eugene Aserinsky discovered the association between rapid eye movement and dreaming. • 78 % of people awakened from REM sleep report dreaming.

20. Importance of REM Sleep • Participants deprived of REM sleep often report feeling more tired. • They may experience dreamlike images during the day • They spend extra time REM sleep following deprivation. This is called REM rebound.

21. Theories of Dreams • Biological Dream Theories • Dreams as interpreted brain activity • Dreaming is simply a by-product of brain activity. • Activation-synthesis theory • A dream is the forebrain’s attempt to interpret the random neural activity initiated in the midbrain during sleep. • There is no consensus on the cause or meaning of dreams.

22. Theories of Dreams • Psychological Dream Theories • Dreams as wish fulfillment (Freud) • Dreams are disguised wishes originating in the unconscious mind. • Dreams as problem solving (emotions) • Dreams provide people with the opportunity to creatively solve their everyday problems. • Dreams as information processing (memory) • Off-line dream theory contends that the cognitive processing that occurs during dreaming consolidates and stores information gathered during the day.

23. Sleep Disorders • Insomnia • Sleep apnea • Narcolepsy – wide-awake to REM • Parasomnias – Stage 3 or 4 • Sleepwalking, sleeptalking • Night terrors • REM sleep behavior disorder

24. Sleep Disorders • Insomnia • recurring problems in falling or staying asleep • Narcolepsy • uncontrollable sleep attacks • sufferer may lapse directly into REM sleep, often at inopportune times

25. Sleep Disorders • Sleep Apnea • characterized by temporary cessations of breathing during sleep and consequent momentary reawakenings • Night Terrors • high arousal-appearance of being terrified • usually in Stage 4, within 2-3 hours of falling asleep

26. Consciousness • Consciousness • a person’s awareness of everything that is going on around him or her at any given moment • Waking Consciousness • state in which thoughts, feelings, and sensations are clear and organized, and the person feels alert LO 4.1 Consciousness and Levels of Consciousness

27. Consciousness • Altered State of Consciousness • state in which there is a shift in the quality or pattern of mental activity as compared to waking consciousness LO 4.1 Consciousness and Levels of Consciousness

28. Necessity of Sleep • Circadian rhythm: a cycle of bodily rhythm that occurs over a twenty-four-hour period • “circa”: about • “diem”: day LO 4.2 Why Sleep and How Sleep Works

29. Necessity of Sleep • Hypothalamus: tiny section of the brain that influences the glandular system • suprachiasmatic nucleus: deep within the hypothalamus; the internal clock that tells people when to wake up and when to fall asleep • The hypothalamus tells the pineal gland to secrete melatonin, which makes a person feel sleepy. LO 4.2 Why Sleep and How Sleep Works

30. Necessity of Sleep • Adaptive theory: theory of sleep proposing that animals and humans evolved sleep patterns to avoid predators by sleeping when predators are most active LO 4.2 Why Sleep and How Sleep Works

31. Necessity of Sleep • Restorative theory: theory of sleep proposing that sleep is necessary to the physical health of the body and serves to replenish chemicals and repair cellular damage LO 4.2 Why Sleep and How Sleep Works

32. Figure 4.1 Sleep Patterns of Infants and AdultsInfants need far more sleep than older children and adults. Both REM sleep and NREM sleep decrease dramatically in the first 10 years of life, with the greatest decrease in REM sleep. Nearly 50 percent of an infant’s sleep is REM, compared to only about 20 percent for a normal, healthy adult. (Roffwarg, 1966)

33. Brain Wave Patterns • Electroencephalograph (EEG) • allows scientists to see the brain wave activity as a person passes through the various stages of sleep and to determine what type of sleep the person has entered • alpha waves: brain waves that indicate a state of relaxation or light sleep • theta waves: brain waves indicating the early stages of sleep • delta waves: long, slow waves that indicate the deepest stage of sleep LO 4.2 Why Sleep and How Sleep Works

34. Stages of Sleep • Rapid eye movement (REM): stage of sleep in which the eyes move rapidly under the eyelids and the person is typically experiencing a dream • NREM (non-REM) sleep: any of the stages of sleep that do not include REM LO 4.3 Stages of Sleep and Dreaming

35. Stages of Sleep • Non-REM stage 1: light sleep • may experience: • hypnagogic images: vivid visual events • hypnic jerk: knees, legs, or whole body jerks • Non-REM stage 2: sleep spindles (brief bursts of activity only lasting a second or two) LO 4.3 Stages of Sleep and Dreaming

36. Stages of Sleep • Non-REM stages 3 and 4: delta waves pronounced • deep sleep: when 50 percent or more of waves are delta waves. LO 4.3 Stages of Sleep and Dreaming

37. EEG Brain Wave Patterns—NREM Sleep

38. Stages of Sleep • Stage:1 hypnogogic state: transition between wakefulness and sleep • myoclonic jerk; hypnogogic hallucinations • Stage 2: lasts about 20 minutes and is characterized by sleep spindles • Stage 3: slow-wave sleep; brain waves higher in amplitude and slower in frequency • Stage 4: delta waves much more pronounced • REM (rapid eye movement) sleep: “Active sleep” completes the sleep cycle.

39. Figure 4.2 Brain Activity During SleepThe EEG reflects brain activity during both waking and sleep. This activity varies according to level of alertness while awake (top two segments) and the stage of sleep (middle segments). Sleep Stages 3 and 4 are indicated by the presence of delta activity, which is much slower and accounts for the larger, slower waves on these graphs.

40. Figure 4.2 (continued) Brain Activity During Sleep[NOTE: The American Academy of Sleep Medicine (Iber et al., 2007) has recently published updated guidelines for the scoring of sleep activity and one major change has been to combine NREM stages 3 and 4 into a single stage, now indicated by N3.] REM has activity that resembles alert wakefulness but has relatively no muscle activity except rapid eye movement. The bottom segments illustrate how EEG activity differs between wakefulness, light and deep sleep, and lastly what it looks like when brain activity has ceased in cerebral death. EEG data and images in this figure are courtesy of Dr. Leslie Sherlin.

41. Figure 4.3 A Typical Night’s SleepThe graph shows the typical progression through the night of Stages 1–4 and REM sleep. Stages 1–4 are indicated on the y-axis, and REM stages are represented by the green curves on the graph. The REM periods occur about every 90 minutes throughout the night (Dement, 1974).

42. The First 90 Minutes of Sleep

43. REM Sleep and Dreaming • REM sleep is paradoxical sleep (high level of brain activity). • If wakened during REM sleep, sleepers almost always report a dream. • REM rebound: increased amounts of REM sleep after being deprived of REM sleep on earlier nights LO 4.3 Stages of Sleep and Dreaming

44. Sleep Disorders • Nightmares • bad dreams occurring during REM sleep • REM Behavior Disorder • a rare disorder in which the mechanism that blocks the movement of the voluntary muscles fails, allowing the person to thrash around and even get up and act out nightmares LO 4.4 Sleep Disorders and Normal Sleep

45. Hallucinations • Hypnogogic Hallucination: a type of hallucination that can occur just as a person is entering Stage 1 sleep • Hypnopompic Hallucination: a hallucination that happens just as a person is in the between-state of being in REM sleep (in which the voluntary muscles are paralyzed) and not yet fully awake LO 4.10 What Are Hypnogogic and Hypnopompic Hallucinations?

46. Stage Four Sleep Disorders • Sleepwalking (Somnambulism) • Occurring during deep sleep, sleepwalking is an episode of moving around or walking around in one’s sleep. Sleepwalking is more common among children than adults. LO 4.4 Sleep Disorders and Normal Sleep

47. Stage Four Sleep Disorders • Night terrors • relatively rare disorder in which the person experiences extreme fear and screams or runs around during deep sleep without waking fully LO 4.4 Sleep Disorders and Normal Sleep

48. Problems during Sleep • Insomnia: the inability to get to sleep, stay asleep, or get a good quality of sleep • Sleep apnea: disorder in which the person stops breathing for nearly half a minute or more • continuous positive airway pressure device LO 4.4 Sleep Disorders and Normal Sleep

49. Problems during Sleep • Narcolepsy: sleep disorder in which a person falls immediately into REM sleep during the day without warning • cataplexy: sudden loss of muscle tone LO 4.4 Sleep Disorders and Normal Sleep