textbook chapter 8 summary

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Published on 31 May 2011
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Nov/2/2003 CHANAPS
Notes From Reading
CHAPTER 5: VARIATIONS IN CONSCIOUSNESS
Chapter 5
Variations in Consciousness
-Rapid eye movements during sleep has a connection with dreams
-Rapid eye movement sleep blossomed into a number of other fascinating
insights about what goes on in the brain during sleep
-We cannot directly observe another’s consciousness
On the Nature of Consciousness
-consciousness is the awareness of internal and external stimuli
-conscious includes 1) your awareness of external events, 2) your
awareness of your internal sensation, 3) your awareness of your self as the
unique being having these experiences and 4) your awareness of your
thoughts about these experiences
-contents of your consciousness are continually changing
Variations in Levels of Awareness
-Conscious and unconscious processes are different levels of awareness
(Sigmend Freud)
-Research shows that people continue to maintain some awareness during
sleep and even when they are put under anesthesia for surgery.
The Evolutionary Roots of Consciousness
-consciousness allowed our ancestors to think through courses of action
and their consequences
-evolutionary bases of consciousness remain indefinable
Consciousness and Brain Activity
-consciousness does not arise from any distinct structure in the brain but
rather from activity in distributed networks of neural pathways
-Electroencephalograph(EEG) summarizes the rhythm of cortical activity
in the brain in terms of line tracings called brain waves.
-Brain wave activity divided into 4 brands: beta (13-24 cps), alpha (8-12
cps), theta (4-7cps), and delta (under 4 cps).
-Change in EEG activity are closely related to variations in consciousness
-Variations in consciousness are correlated with variations in brain activity.
Biological Rhythms and Sleep
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Nov/2/2003 CHANAPS
Notes From Reading
CHAPTER 5: VARIATIONS IN CONSCIOUSNESS
-Biological rhythms are periodic fluctuations in physiological functioning
-Existence of these rhythms means that organisms have internalbiological
clocks that somehow monitor the passage of time
The Role of Circadian Rhythms
-Circadian rhythms are the 24 hour biological cycles found in humans and
many other species
-Body temperature varies rhythmically in a daily cycle, usually peaking in
the afternoon and reaching its low point in the depths of the night
-As body temperature drops people sleep and as it ascends they awaken
-Circadian rhythms in humans actually appear to be regulated by several
internal clocks, but the central pacemaker clearly is located in the
suprachiasmatic nucleus (SCN).
Ignoring Circadian Rhythms
-when you ignore your biological clock and go to sleep at an unusual time
the quality of your sleep suffers
-chronic jet lag is when you travel to places and your biological clock does
not change; this is associated with measurable deficits in cognitive
performance
-Readjustment depends on the direction traveled, and its easier to fly
westward and lengthen your day than it is to fly eastward and shorten it.
-Workers get less total sleep and poorer quality sleep when they go on
rotating shifts
Melatonin and Circadian Rhythms
-promising line of research has focused on giving people small doses of the
hormone melatonin, which appears to regulate the human biological clock
-Melatonin can facilitate daytime naps but may have limited value in the
treatment of night-time insomnia.
-Medical experts are worried that health food stores are encouraging people
to take excessive doses of an untested drug that can raise melatonin levels
in the blood to 1,000 times higher than normal
The Sleep and Waking Cycle
-Researchers in a sleep laboratory can observe subjects while using
elaborate equipment to record physiological changes during sleep.
-This kind of research has disclosed that sleep is a complex series of
physical and mental states
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Nov/2/2003 CHANAPS
Notes From Reading
CHAPTER 5: VARIATIONS IN CONSCIOUSNESS
-Electromyograph (EMG) records muscular activity and tension
-Electrooculograph (EOG) records eye movements
-Electroencephalograph (EEG) records brain waves
Cycling Through the Stages of Sleep
-During sleep, people cycle through a series of five stages
Stages 1-4
-stage 1 is a brief transitional stage of light sleep that usually lasts only a
few (1-7) minutes. Alpha waves that dominate just before falling asleep
are replaced by theta waves
-Hypnic jerks are those brief muscular contractions that occur as people fall
asleep, and they generally occur during stage 1 drowsiness
-As the sleeper descends through stages 2, 3, and 4 of the cycle, respiration
rate, heart rate, muscle tension, and body temperature continue to decline
-Gradually, brain waves become higher in amplitude and slower in
frequency, as the body moves into a deeper form of sleep, called slow-
wave sleep
-Slow-wave sleep (SWS) consists of sleep stages 3 and 4, during which
high-amplitude, low-frequency delta waves become prominent in EEG
recordings
REM sleep
-fifth stage of sleep is most widely known as REM sleep
-Term REM sleep was coined by grad student William Dement.
-Rem stage tends to be a “deep” stage of sleep, in the conventional sense
that people are relatively hard to awake from it
-Dreaming is most frequent, vivid, and memorable during REM sleep
-Rem sleep is a relatively deep stage of sleep marked by rapid eye
movements, high-frequency, low-amplitude brain waves (beta), and vivid
dreaming.
-Non-REM sleep consists of sleep stages 1 though 4, which are marked by
an absence of rapid eye movements, relatively little dreaming, and varied
EEG activity.
Repeating the Cycle
-during the course of a night, people usually repeat the sleep cycle about
four times.
-First REM period is relatively short
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Document Summary

Rapid eye movements during sleep has a connection with dreams. Rapid eye movement sleep blossomed into a number of other fascinating insights about what goes on in the brain during sleep. Conscious and unconscious processes are different levels of awareness (sigmend freud) Research shows that people continue to maintain some awareness during sleep and even when they are put under anesthesia for surgery. The evolutionary roots of consciousness consciousness allowed our ancestors to think through courses of action and their consequences evolutionary bases of consciousness remain indefinable. Consciousness and brain activity consciousness does not arise from any distinct structure in the brain but rather from activity in distributed networks of neural pathways. Electroencephalograph(eeg) summarizes the rhythm of cortical activity in the brain in terms of line tracings called brain waves. Brain wave activity divided into 4 brands: beta (13-24 cps), alpha (8-12 cps), theta (4-7cps), and delta (under 4 cps).