VARIATIONS IN CONSCIOUSNESS

Is this reality or just someone’s imagination of reality?

CONSCIOUSNESS

The awareness of internal and external stimuli

Also includes: Awareness of self as unique Awareness of experiences

VARIATIONS IN LEVELS OF AWARENESS William James---stream of

consciousness Freud believed that stream had depth

(unconscious) Conscious and unconscious are levels

of consciousness

CONSCIOUSNESS AND BRAIN ACTIVITY Consciousness is not centered in one

structure EEG is the best measurement Records brain waves 4 principle waves: beta, alpha, theta,

and delta

BIOLOGICAL RHYTHMS AND SLEEP

Biological rhythms: periodic fluctuations in physiological functioning

Circadian rhythms: 24 hour biological cycles found in humans and many other species

IGNORING CIRCADIAN RHYTHMS

Quality of sleep Crossing time zones causes jet lag Going to bed a couple of hours later

affects rhythm

THE SLEEP AND WAKE CYCLE

CONDUCTING SLEEP RESEARCH

Use EEG Electromyograph (EMG): records

muscular activity and tension Electrooculograph (EOG): records eye

movements

STAGES OF SLEEP---STAGE 1

1: lasts 1-7 minutes; drowsiness; breathing and heart rate decrease; muscle activity declines

Hypnic jerks: brief muscular contractions

Primarily theta waves

STAGES OF SLEEP---STAGE 2

10-25 minutes Sleep spindles: higher-frequency brain

waves Brain waves become higher in

amplitude and slower in frequency

STAGES OF SLEEP---STAGES 3 AND 4

Lasts c. 30 minutes Slow-wave sleep: high amp, low

frequency delta waves prominent After: cycle reverses Before reaching stage one again, ….

REM SLEEP

5th stage Irregular breathing and pulse Virtually paralyzed Beta waves High-frequency, low amp brain waves,

and vivid dreaming Non-REM (nREM): stages 1-4

REPEATING THE CYCLE

Usually repeat c. 4 times REM periods get longer; peak at 40-60

min. NREM periods get shorter Young adults: 60% in light sleep (1 and

2); 20% in slow wave sleep (3 and 4); 20% in REM

AGE AND SLEEP

Infants: 6-8 times in 24 hrs; 16+ hrs total

50% in REM As age increases, deep sleep decreases

in amt Total sleep increases w/age

CULTURE AND SLEEP

Co-sleeping: children and parents sleep together

Discouraged in western societies Napping is cultural; siesta cultures

NEURAL BASES OF SLEEP

Reticular Formation important in sleep and wakefulness

Ascending reticular activating system (ARAS): afferent fibers running through the RF that influence physiological arousal

NEURAL BASES OF SLEEP CONTINUED Pons assoc. with REM sleep Areas in medulla, thalamus,

hypothalamus, and limbic system assoc. with control of sleep and waking

NT’s involved: ACh, serotonin, norepinephrine, dopamine, and GABA

EVOLUTIONARY BASES OF SLEEP

Conserve energy Reduce exposure to predators Helps to restore energy and other

bodily resources Which do you believe?

SLEEP DEPRIVATION

Complete deprivation negatively effects mood, cognitive and perceptual-motor tasks

Difficult to go past 3 or 4 days w/o sleep

Partial deprivation: losing substantially less sleep over a period of time; very common

SLEEP DEPRIVATION CONTINUED

Selective deprivation Repeated disruption of sleep Experiments show rebound effect:

making up time in stages where sleep was interrupted

INSOMNIA

Insomnia: chronic problems in getting adequate sleep

3 main types1: difficulty in falling asleep2: difficulty maintaining sleep3: persistent early-morning waking--assoc. w/ daytime fatigue, impaired functioning, reduced productivity, increased health problems

INSOMNIA

Sleep state misperception: pseudoinsomnia

Causes: anxiety, stress, depression, various health problems

Treatment: sedatives for short term solution

OTHER SLEEP DISORDERS

Narcolepsy: sudden onset of sleep during normal waking periods

Sleep apnea: frequent, reflexive gasping for air that disrupts sleep

Nightmares: anxiety-arousing dreams that lead to awakening, usually from REM

Night terrors: abrupt awakenings from NREM sleep accompanied w/intense autonomic arousal and feelings of panic

Sleepwalking: walking around while asleep