Exam on Wednesday •  80 point, MC exam. You can come early if you think you need

more time •  Limited use of names, but you should know what experiments

found and conclusions from them •  Items will come from lecture and book. You can’t ignore your

book if you want a top grade •  Things I haven’t covered are in the exam

“To Sleep: perchance to dream” Hamlet Circadian Rhythm - daily cycle of biological changes

The Brain’s Time Keeper A Biological Clock? Suprachiasmatic Nucleus of the hypothalamus (Circadian

rhythm generator) •  The SCN controls the sleep-wake cycle in part by regulating the

secretion of the hormone melatonin by the pineal gland about 1 to 2 hours before sleep.

–  Melatonin aids sleep if taken when you are in another time zone, but does not increase tendency to sleep under normal situations since your brain is already doing it.

–  Hypothalamus also important in other cycles, hibernation, migration, ovulation.

•  SCN Receives direct input from special set of receptors in retina. •  Light darkness changes important in circadian rhythm. Zeitgeber

(time giver) stimuli which adjust cycle of SCN. •  If you are in another time zone and feel your rhythms are out of

kilter go to the beach.

What would happen to your circadian rhythms if you were kept in a cave without light cues to determine when you got up and when you went to to sleep? Would you maintain a 24 hr. rhythm? •  Cave experiments. Approximate

circadian rhythm 25 hours rather than 24.

•  Adjust poorly to extremes (18 or 30 hour days).

•  Gustavus weekend jet lag •  Natural cycle helps to explain

Jet Lag

Changing Work Shift Schedules “Morning” and “evening” persons?

What are you like in the morning? If you wake up easily in the morning and become quickly

alert and believe you do your best work in the morning, you are a morning person.

Looks to be a developmental phenomena •  You may be an evening person when you are young but you move

in the direction of becoming a morning person. True for both humans and animals although we don’t know why.

Sleep of Adolescents

Mary Carskadon believes that Adolescents need more sleep •  Older adolescents(16-18) report being sleepier than younger •  If allowed to sleep freely average 9 hours, 25 minutes •  Believes biology sets clock forward an hour and changes release of

melatonin, length may be related to growth hormone release. •  Historically there has been a change in the time when high school

starts. •  Edina high school experience in 1997. Move to 8:40 starting time

from 7:15. –  Fewer behavior problems, illnesses and improved test scores.

Theories for sleep-wakefulness cycle

Restorative-sleep restores “x”. •  We sleep to restore depleted physical reserves depleted •  Slow wave sleep or deep sleep increases after physical exertion •  Lack of sleep leads to impaired concentration, irritability, and

impaired functioning of the immune system

Problems •  People do not sleep less when inactive •  Nothing can be identified that shows change with sleep-Siamese

twins •  There is no repair process that occurs only when we sleep

Evolutionary Theories for Sleep

Survival •  We sleep to preserve energy (demands drop 10-25%) •  We sleep to avoid night dangers. Sleep keeps individual inactive

during dangerous dark period. •  We sleep more when we are sick or injured •  Species differences Predators can afford to sleep more, high

calorie meals and little danger. •  Some animals are on nocturnal schedules others diurnal

Brain waves (EEG) and Sleep

Beta – Normal waking thought and alert problem solving •  High frequency, low amplitude waves when mentally active (13-24 cps)

Alpha – deep relaxation, blank mind, meditation •  large regular waves of 8-13 cycles when relaxed with eyes closed

Stages of Sleep Stage 1, Theta – Light sleep

•  low amplitude and low frequency waves(4-7 cps) Stage 2, Sleep spindles

•  bursts of high amplitude waves Stage 3 & 4, Delta – deep sleep

•  low frequency and high amplitude waves (<4 cps) •  Probably serves a restorative function.

Terminal Stage 1, REM

Rem Sleep

REM Sleep

Characteristics of REM sleep •  Presence of rapid-eye-movements •  Increased autonomic nervous system activity •  EEG resembles that of awake state (beta wave) •  Motor paralysis (except for diaphragm) •  Presence of dreaming

Neurology of Consciousness

Consciousness is distributed throughout the brain •  Prefrontal cortex is key for

conscious control of information processing, inactive in sleep. Accounts for “irrationality of dreams”

•  Reticular Formation controls alertness. Damage to the reticular formation can lead to coma.

•  Neurons in Pons critical in generating REM sleep

•  Medial Medulla important in inhibiting motor movements. Damage leads to acting out our dreams.

What we know about dreams

Length of dreams •  Approximates the time it would take in waking life

Content •  Our eye movements are correlated with dream activity

Who Dreams? •  Everyone dreams, not everyone remembers, “Non-dreamers” less

likely to remember 46% vs 83%.

How much do we dream? •  4 or 5 bouts of about 10-20 dreams a night (20%) •  Age differences in REM

Additional Findings About REM Do we only dream during REM?

•  Story type dream only found in REM. NREM more like passing thoughts or thinking. Recent research suggests dreams occur at other times.

•  Lucid dreaming

Do we need REM sleep? NREM? •  Deprivation studies show REM rebound

–  Since stages 3 & 4 of deep sleep also involved, people feel more tired and bothered by muscle and bone pain

•  Dreams may be way of exercising our neurons to keep them in shape or getting oxygen to cornea

•  REM sleep is correlated with learning. –  REM sleep increases in college students during examination

time. –  Deprivation of REM sleep impairs the ability to learn complex

tasks

Sleep Does everyone sleep?

•  Nonsomniacs •  Individual differences in sleep needs •  How much sleep should you have. Most 8 hours but wide

individual differences.

Mortality Rates and Sleep

(Figure adapted from Kripke et al., 1979)

Sleep Deprivation

Sleep Deprivation. Do you go crazy without sleep? •  The cases of Peter Tripp and Randy Gardner (264 hours or 11 days

without sleep) •  Key finding: Lack of sleep makes you tired but no physical

damage. If sufficiently motivated you can perform quite well

Are we sleep deprived? •  Estimates are that 50% of population needs more sleep. •  Studies show that optimal functioning helped by getting regular

sleep of 8 hours or more and those who increased their sleep time did better.

–  Problems of insomnia in older people.

Sleep Problems

Periodic limb movement disorder •  Restless leg or kick that wakes up. Increases with age.

Sleep Apnea •  Problem of breathing and sleeping at the same time. SIDS

Narcolepsy •  Sudden intrusion of Rem sleep causing cataplexy (loss of skeletal muscle

tone) hypnagogic hallucinations. Persistent daytime sleepiness. •  Deficiency in Orexin or brain receptors for the neurotransmitter. Orexin

keeps you awake rather than alternating between sleep and wakefulness. •  Unlike normals, move directly to REM sleep at night. tape

Sleep Problems Insomnia.

•  Sleep onset-you cannot get to sleep when you go to bed •  Sleep awakening-you get to sleep but you keep waking up •  Early termination-you get to sleep but you wake up too early •  Light sleep-you feel that you never really got to sleep

How to sleep like a baby

•  Do you really need that much sleep as you think? •  Clear you mind of obsessive thoughts and worries

before going to bed. Paradoxical intention. •  Keep a regular schedule of sleeping and waking and

avoid long afternoon naps. •  Don’t got to bed until you are tired. •  Make your bed a place to sleep. •  Adopt a regular program of exercise.

•  Should you exercise before going to bed.

•  Avoid sleep medications. •  Have faith that your circadian rhythms will carry you

though the next day

Psychodynamic View of Consciousness

Freud argued that three mental systems form consciousness •  Conscious: mental events that you are aware of •  Preconscious: Mental events that can be brought

into awareness •  Unconscious: Mental events that are inaccessible

to awareness; events are actively kept out of awareness

Sigmund Freud’s Theory of Dreams

Freud believed dreams gives us a closer look at the workings of the unconscious. Divided dreams into: •  Manifest content of a dream or the story of our dream •  Latent content or the source of the dream in the unconscious

Freud thought dreaming allows us to remain sleeping when any of the following threaten to wake us: •  nocturnal sensory impressions •  daytime preoccupations •  unconscious impulses.

“Dream Work”

•  According to Freud, dream work allows us to incorporate those things which threaten to wake us by disguising images of the impulses which created them.

•  The extent of the disguise depends on the individual’s “dream censor.”

•  Since dreams contain visual symbols we are likely to miss their symbolic meaning.

•  Distortions are dynamic, emotions may appear opposite to what they are.

Common Dream Symbols Body - houses Parents - royalty, persons in power Siblings - little animals or vermin Birth - water Dying - journey Uniform – nakedness Rhythmic activities, dancing, playing piano—intercourse or masturbation Penis - generally any object that can penetrate, or is pointed or elongated, or defy gravity. Sticks, knives, umbrellas etc., Female genitalia - churches, ovens, receptacles Breasts – apples, peaches, fruit in general Male genitalia - machinery, a grouping of three

Where do these symbols come from? Is there empirical support for dream symbols?

Are Dreams the workings of Unconscious?

Problems with Freud •  Freud’s dream theory has difficulty with “Sexual” Dreams and “nonsexual” dreams.

•  Problem with Freud is that he suggests that there is a homunculus that controls our behavior

An alternative explanation: Hobson and McCarley’s

Activation-Synthesis Theory •  Random firing from subcortical brain structures reach the cortex

creating “stimuli” that the cortex attempts to explain in a dream. •  Brain tries to make sense of these images in our dreams. •  This is the reverse of Freud who believed that meaning occurred

first creating the dream, rather than random signals being given meaning.

Hypnotic Phenomena

Disinhibition- will people engage in behavior that is unusual or immoral •  People will follow suggestions. (Orne & Evans,1965) Snake,

nitric acid, assault 5/6 followed directions. Complicating factor is that nonhypnotized people will often follow directions too.

Sensory distortions or hallucinations •  Some report auditory or visual hallucinations. Brain areas

activated differently than if asked to imagine Posthypnotic suggestions Analgesia Recovery of forgotten memories Age regression

Can You Fake Being Hypnotized?

Are people who are hypnotized engaged in a social role? Fooling hypnotist relatively easy.

•  Non hypnotized can often handle pain and show highly similar emotional and physiological reactions.

•  Some differences –  Hallucinatory experiences different –  Will be likely to declare they are “extremely hypnotized”

The case of Kenneth Bianchi, the “Hillside Strangler” •  Under hypnosis discovered alter ego in multiple personality of

Steve Walker

Theories of Hypnosis

Adoption of social role of hypnotized person

But how do you explain analgesia?

Hilgard's "Hidden Observer“ A case of dissociation.

Altered state of consciousness? Most recent evidence suggests EEGs look different.