1. Variations in Consciousness
Chapter 5
Variations in Consciousness

2. On the Nature of Consciousness
Consciousness – Awareness of internal and external stimuli
Your awareness of external events
Your awareness of your internal sensations
Your awareness of your self as the unique being having these experiences
Your awareness of your thoughts about these experiences

3. Consciousness and Brain Activity
Electroencephalograph (EEG)- Device that monitors the electrical activity of the brain over time by means of recording electrodes attached to the surface of the scalp.
Variations in consciousness are measured using an EEG.
Brain waves – line tracing that indicates the rhythm of cortical activity
Amplitude – height
Frequency – cycles per second (cps)

4. EEG Patterns EEG Pattern Frequency (cps
Typical States of Consciousness
Beta
13-24
Normal waking thought, alert problem solving
Alpha
8-12
Deep relaxation, blank mind, meditation
Theta
4-7
Light sleep
Delta
Less than 4
Deep sleep

5. Biological Rhythms and Sleep
Biological Rhythms – Periodic fluctuations in
physiological functioning
Internal “biological clocks” that monitor the passage of time
Biological rhythms are reflected through the following as
well as various others:
Daily alteration of light and darkness
Annual patterns of the seasons
Phases of the moon

6. The Role of Circadian Rhythms
Circadian Rhythms- The 24 hour biological cycles found
in humans and many other species
Influential in the regulation of sleep
People generally fall asleep when their body temperature begins to drop and awaken once it begins to increase again
Light enters retina
Receptors in retina send information to suprachiasmatic nucleus in the hypothalamus
SCN sends signals to pineal gland
Pineal gland secretes melatonin
Melatonin plays a key role in adjusting biological clocks

7. Ignoring and Realigning Circadian Rhythms
Consequences of Ignoring Circadian Rhythms
Quality of sleep suffers
Causes Jet Lag (It’s easier to fly Westward and lengthen your day than it is to fly Eastward and shorten your day)
Feel fatigued, sluggish, and irritable
Realigning Circadian Rhythms
Doses of melatonin
Exposure to bright light
Carefully plan rotation schedules
Readjustment for Jet Lag takes 1 day for each time zone crossed when flying Eastward and 2/3 when flying Westward

8. The Sleep and Waking Cycle
Devices used to study sleep and wake cycles
Electromyograph (EMG) – Records muscular activity and tension
Electrooculograph (EOG) – Records eye movement
Electrocardiograph (EKG) – Records the contractions of the heart
Other instruments are used to monitor body
Temperature, breathing, and pulse rate.

9. Cycling Through the Stages of Sleep
The average length of time that it takes for people to fall asleep is approximately 25 minutes
Stage 1 is a brief transitional stage of light sleep that lasts only minutes
Breathing and heart rate decrease
Muscle tension declines
Body temperature declines
Lower frequency EEG activity
Theta waves are prominent

10. Cycling Through the Stages of Sleep
Stages 2, 3, and 4
Respiration, heart rate, muscle tension, and body temperature continues to decline
Brain waves become higher in amplitude and slower in frequency
Move into slow-wave sleep
Slow-wave sleep – consists of sleep stages 3 and 4, during
which low frequency delta waves are prominent in EEG
Recordings
Reach slow-wave sleep in approximately one hour and remain there for half an hour
Cycle begins to reverse itself

11. Cycling Through the Stages of Sleep
REM Sleep
REM – Rapid Eye Movement
REM sleep is reached when sleep cycle is reversed and you reach what should be stage 1
Deep stage of sleep
Difficult to awaken a person at this stage
Marked by irregular breathing and pulse rate
Muscle tone is extremely relaxed
EEG dominated by high frequency beta waves resembling the alert and awake state

12. REM & NREM Sleep REM Sleep
Deep stage of sleep marked by rapid eye movements, high frequency brain waves, and dreaming
Dreaming is most vivid, frequent, and memorable.
Non-REM sleep (NREM)
Consists of sleep stages 1-4, which are marked by an absence of rapid eye movements, relatively little dreaming,

13. Sleep Stages

14. Age, Culture, and Sleep
Newborns sleep 6-8 times in a 24 hour period (appx. 16 hours per day)
50% of babies’ sleep is spent in REM sleep
From adolescence on until later adulthood the average time spent in REM sleep is 20%
With increased age, the percentage of time spent in stage 1 sleep increases slightly.
There is a shift towards lighter sleep with increased age

15. Sleep Disorders Insomnia – chronic problems in getting adequate sleep
Difficulty in falling asleep initially
Difficulty in remaining asleep
Persistent early morning awakening
Narcolepsy – Disease marked by sudden and irresistible
onset of sleep during normal waking periods.
Goes directly from wakefulness into REM sleep
Sleep apnea – frequent, reflexive gasping for air that
awakens a person and disrupts sleep
Occurs when a person stops breathing for a minimum of 10 seconds
Somnambulism (sleepwalking) – Occurs when a person arises and wanders about
while remaining asleep
Mostly occurs during the first 3 hours of sleep and during slow-wave sleep
Episodes may last anywhere from 15 seconds to 30 minutes