States of Consciousness

Consciousness  The awareness we have of ourselves and our environment

 Different states of consciousness are associated with different patterns of brain waves as measured using an electroencephalograph (EEG)

Sleep

Biological Rhythms  Sleep is affected by biological rhythms or periodic physiological changes  Biological rhythms are regular, periodic changes in a body’s functioning

Circadian Rhythms  Biological cycles that occur about every 24- hours

Infradian Rhythms  Biological cycles that take longer than 24- hours

Ultradian Rhythms  Biological cycles that occur more than once a day

 Biological rhythms usually synchronize with environmental events & many continue without cues from the environment

Biological Clocks  Endogenous rhythms exist because the body has biological clocks that keep time  The suprachiasmatic nucleus (SNC)

Jet Lag  People experience jet lag when the event sin the environment are out of sync with their biological clocks

The Function of Sleep  We don’t really know why people sleep.  Several theories exists that attempt to answer the why’s of sleep.

Sleep Research  Researchers study sleep by monitoring subjects who spend the night in labs, and they use various instruments for different purposes

 Electroencephalographs (EEG): record brain waves  Electromyographs (EMG): record muscle activity  Electrooculographs (EOG): record eye movements  Electrocardiographs (EKG): record the activity of the heart

Sleep Stages  During one night’s sleep, people pass through several cycles of sleep

Stages 1-4  When people are relaxed and ready to fall asleep, their EEG will show mostly alpha waves  When people fall asleep, they enter into stage 1 sleep, which lasts just a few minutes  In stage 1, the EEG shows mostly theta waves

 Stage 2 lasts about 20 minutes and is characterized by short bursts of brain waves called sleep spindles

 In stages 3 and 4, which together last about 30 minutes, the EEG displays mostly delta waves

REM Sleep  At the end of stage 4, people go back through the stages in reverse, from 4 to 3 to 2 to 1  When they reach stage 1, instead of waking up, people go into REM, or rapid eye movement, sleep –A single cycle might look like this: REM REM

 During REM sleep, pulse rate and breathing become irregular, eyes move rapidly under closed lids, and muscles remain very relaxed  Although dreaming happens in other sleep stages as well, dreams are most vivid and frequent during REM sleep

 People typically go through about 4 sleep cycles during one night of sleep  The REM stage of sleep gets longer and longer as the night passes, while stage 3 and 4 sleep gets shorter and shorter  About minutes in REM each night

Sleep Deprivation  Different people need different amounts of sleep  Insufficient sleep can have negative effects  REM rebound

Aging and Sleep  Sleep patterns change as we age  Newborn babies spend about two-thirds of their time in sleep  As they age, they tend to sleep less  Amount of time spent in REM also changes

 From age 1 to the mid-20s, approximately 25% of total sleep is spent in SWS  After mid-20s, daily sleep pattern becomes stable from now until about age 60, except for SWS which drops dramatically after age 30

 The younger a person is, the more sleep they require

Sleep Disorders  Everyone has occasional difficulty sleeping  These disorders are chronic in nature

 Insomnia –A chronic problem with falling and staying asleep –Basic patterns of insomnia

 Narcolepsy –A tendency to fall asleep periodically during the day –Can be dangerous –Cause of narcolepsy is unknown

 Sleep apnea –A condition in which a person stops breathing many times during a night’s sleep –Can be a very dangerous condition

 Night Terrors –Abrupt awakenings from non-REM sleep accompanied by intense autonomic arousal and feelings of panic –Most common in children ages 2-6, although it sometimes occurs in adults –Tends to run in families –Why is still a mystery –Not indicative of psychological problems

 Sleep Starts –Most people have experience the common motor sleep start - a sudden, often violent, jerk of the entire body that occurs upon falling asleep. –Other forms of sleep starts also occur just as sleep begins such as, but these occurrences are harmless.

 Sleep Talking (somniloquy) –Sleep talking is a normal phenomenon and is of no medical or psychological importance.

 Sleepwalking (somnambulism) –Estimated 10% at least one episode –Not acting out a dream –Cause is unknown, may be affected by stress –Typically occurs during SWS –Most common among children (4-12) –Typically not serious, but can be “scary”