Sleep & Body Rhythms

What is Consciousness?• Consciousness – Your immediate awareness of thoughts,

sensations, memories, and the world around you. Experience of this tends to blend together.

• William James – described consciousness as a "stream" or "river" that is always changing but unified and unbroken.

• Consciousness first studied through introspection (verbal self-reports) and later rejected in favor of studying only observable overt behavior.

• 1950's brought a new desire to study consciousness for two reasons.

1. Complete understanding of behavior had to consider the role of conscious mental processes.

2. Psychologists had created more objective ways to study consciousness.

Body Rhythms•Natural variations we experience daily in our consciousness as a part of our sleep-wake cycle. •Most people experience at least two peaks in mental alertness:

1.morning around 9:00 or 10:00 and 2.8:00 or 9:00 PM. –Slumps in your mental alertness occur at about 3:00 PM and 3:00 AM.

Biological Rhythms• Periodic physiological fluctuations

• Can affect physiological functioning

• Fall into three main categories

– Circadian Rhythms

– Ultradian Rhythms

– Infradian Rhythms

Circadian Rhythms• Any rhythmic change that occurs approximately

once in a 24-hour cycle • body temperature

• cortisol secretion

• sleep and wakefulness

• In the absence of time cues, the cycle period will become somewhat longer than 24 hours

• Many of your processes like blood pressure, hormones, pain sensitivity along with sleep and wake cycles vary over the day

Sleep and Circadian Rhythms

• Play “Sleep and Circadian Rhythms” (6:09) Module #13 from The Brain: Teaching Modules (2nd edition).

• Intro to Circadian Rhythms & Cave Experiment

The Body’s Clock• Suprachiasmatic

nucleus (SCN)—cluster of neurons in the hypothalamus that governs the timing of circadian rhythms

• Melatonin—hormone of the pineal gland that produces sleepiness

The Body’s Clock: How it works• Special photoreceptors in the retina regulate the

effects of light on the body’s circadian rhythms • In response to morning light, signals from these

special photoreceptors are relayed via the optic nerve to the suprachiasmatic nucleus.

• In turn, the suprachiasmatic nucleus causes the pineal gland to reduce the production of melatonin, a hormone that causes sleepiness.

• As blood levels of melatonin decrease, mental alertness increases.

• Daily exposure to bright light, especially sunlight, helps keep the body’s circadian rhythms synchronized and operating on a 24-hour schedule.

How Melatonin works:• More melatonin = sleepy and reduce activity levels

(between 1-3 AM)• Less Melatonin = more alert and active. Body stops

produced melatonin shortly before sunrise and sunlight suppresses melatonin levels throughout the day

• Jet Lag – Since your body is still operating on the time you left from, your melatonin levels will be off causing a disruption in your circadian rhythms and making you mentally fatigued, depressed, irritable and have problems sleeping.

• Night workers will always have some problems due to sunlight resetting their biological clock.

Biological Rhythms

• Play “Can You Beat Jet Lag?” (6:44) Segment #15 from Scientific American Frontiers: Video Collection for Introductory Psychology (2nd edition).

• How light is used by the body to “reset” your biological clock.

Circadian Rhythms

• Play “Circadian Rhythms” (3:58) Segment #9 from Psychology: The Human Experience.

• Lack of Sleep (on-call workers) & Job Performance

• What are the “down times” during the day?

Ultradian Rhythms

• Biological rhythms that occur more than once each day

• Example: Cycling through the stages of sleep throughout the night

Infradian Rhythms

• Biological rhythms that occur once a month or once a season

• Example: Women’s menstrual cycle or a bear’s winter hibernation

Biorhythms vs. Circadian Rhythms

• Biorhythms – pseudoscience that says people have three natural rhythms that follow cycles. 23-day physical cycle, 28-day emotional, and 33-day intellectual functioning. These are determined by the date of your birth.

• Chronobiology – study of biological rhythms over time. Studies have not scientifically proven that biorhythms play a role in certain events (pg. 141).

A Sleep SurveyMost people will spend about 22 years of

their life sleeping. How much are you spending?

1. To the nearest quarter hour, what is your bedtime on a school night?

2. On the average, how many minutes does it take you to fall asleep after going to bed?

3. To the nearest quarter hour, how many hours of sleep do you get on an average school night?

A Sleep Survey

4. In an average night, how many times do you wake up?

5. On a scale of 1 to 10, with one being poor and 10 being wonderful, rate the quality of your sleep on a typical night.

6. On a scale of 1 to 10, with one being easy and 10 being difficult, how hard is it for you to wake up in the morning?

A Sleep Survey

7. In a typical 7-day week, how many naps do you take?

8. When are you generally most awake and alert?

-Morning

-Afternoon

-Evening

-Night

A Sleep Survey

9. After a typical night’s sleep, how many dreams do you recall?

10. Which term most accurately describes your typical dream?

-Pleasant

-Unpleasant

-Neutral

Sleep and Sleep Deficit

Sleep Deprivation Effects• Hurts performance on simple, boring tasks more than

challenging ones• Decreases efficiency of immune system functioning• Raises the levels of stress hormone cortisol which is linked

to damage of the brain cells responsible for learning & memory

• Safety and accident issues• Contributes to hypertension, impaired concentration,

irritability, premature aging, etc.• After one night of sleep deprivation, people have episodes

of sleep lasting a few seconds called microsleeps• See NBC Report on Sleeplessness in America (2 min)• See NBC Report on Sleep Study (3 min)

Sleep Deprivation(National Transportation Safety Board, 1995)

Why We Sleep•Most people need 8-8.5 hours of sleep to function but most Americans sleep 7-7.5 hours. Almost 1/3 of Americans get less than 6 hours. 74% women sleep less than 8 hours a night.

•Most teens need 9 hours and 15 minutes of sleep a night. Average teenager's biological clock doesn't prepare them to awaken until 8 or 9 AM. This can interfere with memory and learning. Students with most sleep did better on grades and exams.

•Getting less sleep than you need can cause harmful changes in metabolic and endocrine functioning. Study found after only one week of sleep restriction of 4 hours of sleep a night, subjects had glucose levels that were no longer normal.

•REM deprivation will cause subjects to have REM rebound in which they spend more time in REM sleep in an effort "catch up."

•Stage 3 & 4 NREM deprivation – people will have NREM rebound and "catch-up" by spending more time in these stages.

Functions of Sleep• Restoration theory—body wears out during the day

and sleep is necessary to put it back in shape– NREM sleep sees increases in the release of growth

hormone, testosterone, prolactin.– REM sleep plays a role in rate of brain development that

occurs in the early stages of the lifespan.

• Adaptive theory—sleep emerged in evolution to preserve energy and protect during the time of day when there is little value and considerable danger– Animals with few natural predators sleep the most while

animals with many sleep less. – Hibernation occurs during the time of year most hazardous

to the animal.

Hypothalamus

• Sleep control center in the brain

• Monitors changes in light or dark in the environment

• Changes levels of hormones in the body

Melatonin

• A hormone that helps regulate daily biological rhythms

• Linked to the sleep-wake cycle

• Melatonin level increases during the night and decreases with exposure to morning light

IMPROVING SLEEP & MENTAL ALERTNESS

• Dealing with Morning Brain Fog or Sleep Inertia• Staying in bed until the last possible moment will

only intensify disorientation as you hustle to work.• Best way to treat it is to allow for more passage of

time. • Set your alarm 15 minutes earlier and make it so you

have to get up to turn it off. • Drink something with caffeine and sit near sunlight. • Read something to get your brain engaged.

Coping with the Night Shift

• Avoid frequent shift changes• Easier to lengthen your days than shorten

them. Progress morning to evening to night shifts.

• If working at night use bright lights especially early on in the shift to adjust your circadian rhythm.

• Take melatonin in the daytime to help you sleep.

Sleep Deprivation Studies

• Play “Catching Catnaps” (11:45) Segment #13 from Scientific American Frontiers: Video Collection for Introductory Psychology (2nd edition).

• Which stages of sleep are most important?

• Can a person survive on naps alone?

• How does lack of sleep or “bonus” sleep affect mood?

Improving the Quality of Your Sleep• Avoid going to sleep in the "forbidden zone" of wakefulness that

usually occurs between 8-10PM.• Don't drink or eat caffeine-containing drinks or foods. See table

4.7 on pg. 175 for common sources of caffeine.• Don't go to bed very hungry or full• Moderate exercise during the day helps but not just before sleep.• Raise your core body temperature with a warm bath or shower.• Develop a consistent bedtime routine.• Avoid depressant drugs which promote sleep but reduce REM

sleep.• Write down concerns and why you plan to do about them the

next day or redirect your thoughts to something relaxing to deal with stress.

Sleep Stages, REM, and Dreaming:

The Stages of Sleep

Electroencephalograph (EEG)

• A machine that amplifies and records waves of electrical activity that sweep across the brain’s surface

• Electrodes are placed on the person’s scalp to measure the waves

• Used as a means to measure the stages of sleep

Electroencephalogram (EEG)

• Electrodes placed on the scalp provide a gross record of the electrical activity of the brain• EEG recordings are a rough index of psychological states

EEG Waves of Wakefulness

• Awake, but non-attentive: large, regular alpha waves

1 second

Alpha waves

Awake, nonattentive

1 second

Beta waves

Awake, attentive• Awake and

attentive: low amplitude, fast, irregular beta waves

Onset of Sleep• Awake & alert, your brain produces small, fast brain

waves called beta waves.• As you lay down and close your eyes, your brain's

electrical activity gradually gears down generating slightly larger and slower alpha brain waves.

• During drowsy, presleep stage you may experience vivid sensory phenomena called hypnagogic hallucinations.

• Most common hallucination is that of falling which can produce a myoclonic jerk or sleep starts – involuntary muscle spasm of the whole body that jolts the person completely awake.

Stage 1 Sleep• Breathing is slowed.• Brain waves become irregular.• It is easy to wake the person, who will

insist they are not asleep.• Lasts only a few minutes. • Familiar sounds fade away but your can

regain alertness if something interrupts you.

• Some imagery is common although no very strange or vivid.

Stages of Sleep

Stage 1

Stage 1

Stage 2 Sleep• Brain wave cycle slows.

• Appearance of sleep spindles or brief bursts of brain activity and K complexes or large high-voltage spikes of brain activity that periodically occur.

• Brain activity slows considerably and breathing becomes rhythmic.

• Slight muscle twitches occur.

• Brain waves begin to slowly switch from Theta waves to slower and larger delta waves.

Stage 2

K Complex

Stages 3 and 4 Sleep“Slow Wave Sleep”

• Increase in delta waves (large and slow waves per second) 20% = Stage 3. More than 50% = Stage 4.

• First time through stage 4 is about 30 minutes and is where one gets rejuvenated

• During the first stage 4 of sleep, heart rate, blood pressure and breathing drop to their lowest levels and it is very hard to wake up.

• Sleepwalking occurs here. • People can "wake up" during stage 4 and do a

simple task and not remember it.

Stage 3

Stage 4

Stages of Sleep1-4Quick Review

• Sleep stage 1: brief transition stage when first falling asleep

• Stages 2 through 4 (slow-wave sleep): successively deeper stages of sleep

• Characterized by an increasing percentage of slow, irregular, high-amplitude delta waves

Delta waves

Sleep stage 11 second

Sleep stage 4

Sleep stage 2

Spindlers (bursts of activity)

REM Sleep• Stages 1 - 4 considered N-REM (non-REM

sleep)• Rapid eye movement (REM Sleep) as eyes move

quickly back and forth• Most dreaming occurs in REM sleep but muscle

activity is suppressed to keep you acting them out.

• If denied REM sleep and then allowed a person will experience REM Rebound and will increase their time in REM by 50%. “Catching Up” on REM sleep.

REM Sleep

REM: Paradoxical Sleep• During REM sleep brain wave patterns are

similar to when a person is awake• Visual and motor neurons in the brain fire like

they do when you are awake.• Eyes dart back and forth and heart rate, blood

pressure and respirations fluctuate up and down.

• REM sleep is sometimes called paradoxical sleep as one’s physiology is close to that of being awake but the brainstem blocks all muscle movement

• The first REM cycle lasts for 5 to 15 minutes.

Stages of Sleep

• Upon reaching stage 4 and after about 80 to 100 minutes of total sleep time, sleep lightens, returns through stages 3 and 2

• REM sleep emerges, characterized by EEG patterns that resemble beta waves of alert wakefulness– muscles most relaxed– rapid eye movements occur– dreams occur

• Four or five sleep cycles occur in a typical night’s sleep; less time is spent in slow-wave, more is spent in REM

Typical Night’s Sleep

Stage 4/REM Changes

Sleep Changes through Life

Sleep• Play “Sleep: Brain Functions” (11:12)

Module #14 from The Brain: Teaching Modules (2nd edition).

• Review of the stages of sleep.• What happens to animals that are not

allowed to sleep?• What defines normal & abnormal sleep?• Categories of Sleep Disorders

Dream Facts:• 25% of your night’s sleep or 2 hours is spent dreaming.• Sleep Thinking – Vague, uncreative, bland thoughts about real-

life events that take place in NREM. Occur more than dreams.• Dreams have 5 basic characteristics:• Emotions can be intense• Content & Organization are usually illogical• Sensations are sometimes bizarre• Bizarre details are uncritically accepted• Dream images are difficult to remember• Dreams occur in both NREM and REM sleep however they are

more frequent and last longer in REM. • People usually have 4-5 episodes of dreaming a night. Dreams

happen in real time.

Brain During REM Sleep

•PET scans reveal that brain activity is much different in REM sleep than when you’re awake.

•Frontal Lobe and Primary Visual Cortex (registers visual info from retinas) are essentially shut down during REM meaning you are shut out from the external world and rational thought so you accept your dreams no matter how bizarre they are.

•Amygdala & hippocampus of the limbic system which deal with emotion and memory are highly active as are the brain’s visual areas.

What do we Dream About?• Most dreams are about everyday life.• Some themes are found across cultures. (See

Common Dream Themes Table 4.3 pf. 155)• Aggression is more common than friendliness in

dreams.• Environmental cues during dreaming may be

incorporated into the dream.

• What you really want to know about dreams? (Read more - In Focus 4.4, pg. 157)

Why don’t remember our dreams?

• Areas of the brain used in forming memories (frontal lobe) are shut down during REM sleep and neurotransmitters that are used to make memories are greatly reduced.

• More likely to remember a dream if you wake up during it. Visual encoders tend to be better at remembering dreams. Vivid dreams are more likely to be recalled.

• Distractions when you awaken can cause problems with remembering dreams.

• Brain seems programmed to forget most of what occurs during sleep.

Types of Dreams

•True dream—vivid, detailed dreams consisting of sensory and motor sensations experienced during REM

• Sleep thought—lacks vivid sensory and motor sensations, is more similar to daytime thinking, and occurs during slow-wave sleep

• Lucid dreaming

Physiological Function Theory

• Neural activity during REM sleep provides periodic stimulation of the brain.

Psychoanalytic Interpretation• Sigmund Freud – Dreams are the fulfillment of

wishes. Unacceptable thoughts of sex & aggression are repressed when you are conscious but come forth when you are asleep in the form of dreams.

• Dreams were “the royal road to the unconsciousness” and a “safety valve” that allowed for the release of unconscious and unacceptable urges.

• Two components of Dreams• Manifest Content – dream images themselves• Latent Content – Disguised psychological meaning of

the dream.• Research does not support his theories.

Activation Synthesis Model• Brain activity during sleep produces dream

images (activation) which are combined by the brain into a dream story (synthesis).

• Meaning is to be found by analyzing the way the dreamer makes sense of the progression of chaotic dream images.

OR, to put it another way:• Activation of brain stem area (Pons) arouse

other brain areas including visual and auditory and limbic systems.

• Brain responds to these internally created signals and assigns them meaning using memories, emotions and sensations.

Activation-Synthesis Theory

• Dreams are the mind’s attempt to make sense of random neural firings in the brain as one sleeps.

Information-Processing Theory

• Dreams serve an important memory- related function by sorting and sifting through the day’s experiences

• Research suggests REM sleep helps memory storage.

REM & Memory Consolidation

• Memory Consolidation – converting new memories into a long-term, relatively permanent form.

• REM seems to help with procedural memories (skills like riding a bike).

• REM seems to improve performance on learned tasks.

• Brain areas activated during training on a task actually are reactivated during REM sleep perhaps stabilizing the neural connections formed in the recent training experience.

Dream Research• Play “What’s in a Dream?” (13:00) Segment #14 from

Scientific American Frontiers: Video Collection for Introductory Psychology (2nd edition).

• Dream research with Alan Alda.• What happens biologically when we dream during REM

sleep?• Where do stories of our dreams come from?• How brains try to make sense of nonsense.• What kind of tasks are more difficult if you have

random sleep loss?• Can dreaming help us learn?

Sleep Disorders and Sleep Problems:

Individual Differences in Sleep Drive

• Some individuals need more and some less than the typical 8 hours per night

• Nonsomniacs—sleep far less than most, but do not feel tired during the day

• Insomniacs—has a normal desire for sleep, but is unable to and feels tired during the day

Sleep Disorders Quick List• Insomnia—inability to fall asleep or stay asleep• REM sleep disorder—sleeper acts out his or her

dreams• Night terrors—sudden arousal from sleep and intense

fear accompanied by physiological reactions (e.g., rapid heart rate, perspiration) that occur during slow-wave sleep

• Narcolepsy—overpowering urge to fall asleep that may occur while talking or standing up

• Sleep apnea—failure to breathe when asleep – See clip of it here.

Insomnia

• Recurring problems falling asleep or staying asleep

• Sleeping pills tend to inhibit or suppress REM sleep; worsen the problem

• Alcohol suppresses REM sleep; also worsens the problem

• Studies show most people overestimate how long it took them to get to sleep

Sleep Apnea

• A sleep disorder characterized by temporary cessations of breathing during sleep and consequent momentary reawakenings.

• Tend to be loud snorers

• Continuous Positive Airway Pressure machine

Narcolepsy

• A sleep disorder characterized by uncontrollable sleep attacks

• Person goes directly into REM sleep• Nervous system getting aroused tends to trigger the

sleep attack• Narcolepsy has a genetic link and runs in some breeds

of dogs.• Rusty the Narcoleptic Dog (Click to View)• Other Dogs with Narcolepsy (Click to View)• Teenagers Living with Narcolepsy (Click to View)

Somnambulism

• Formal name for sleepwalking

• Starts in the deep stages of N-REM sleep

• Person can walk or talk but remembers nothing of the experience

• Sleep Walking has been linked to Sleep Deprivation. (NBC Report – 2 min.)

Night Terrors• Sleep disorder characterized by high arousal and

appearance of being terrified

• Happens during stage 4 sleep; mostly children

• The children seldom remember the event.

Other Sleep Disorders

• Bruxism – teeth grinding

• Enuresis – bed wetting

• Myoclonus – sudden jerk of a body part occurring during stage 1 sleep

– Everyone has occasional episodes of myoclonus