Sleep Research What do

psychologists who conduct sleep research measure during their studies? . . . . .

The electroencephalograph (EEG), which

records brain electrical activity (brain waves) The electromyograph (EMG), which records

muscle activity and tension The electrooculograph (EOG), which records

eye movements.

Sleep/Waking Research

They may also record heart rate, breathing rate, temperature, etc., as well as videotape the person sleeping through a window.

Psychologists who conduct sleep research use the following instruments a great deal:

“The behavior patterns involved in sleep

are glaring, almost insanely, at odds with common sense.”

Christopher Evans (British psychologist)

Rhythms of Sleep

Measuring sleep:

About every _____ minutes

We pass through a cycle of _______ distinct sleep stages.

Sleep Stages

There are five identified stages of sleep:

It takes about 90-100 minutes to pass through the 5 stages.

The brain’s waves will change according to the sleep stage you are in. The first four stages are known as NREM sleep… The fifth stage is called REM sleep.

Sleep Stages

Awake

• When an individual closes his eyes but remains awake, his brain activity slows down to a large amplitude and slow, regular alpha waves.

• A meditating person exhibits an alpha brain activity.

Awake but RelaxedAwake but Relaxed

• When an individual is awake and alert, his brain waves are very active – these are called beta waves..

This is experienced as falling to sleep and is a

transition stage between wake and sleep. It is when you feel yourself drifting on the edge of

consciousness.

It usually lasts between 1-7 minutes and occupies approximately 2-5% of a normal night of sleep. Eyes begin to roll slightly. Hypnic jerks, those brief muscle contractions that occur

when one is falling asleep, occur in stage 1 sleep. Hallucinations can occur and feeling of falling.

Stage One

Consists mostly of theta waves (high amplitude, low

frequency (slow)). A person who is daydreaming shows theta activity as well.

Brief periods of alpha waves, similar to those present while awake

Stage One

This stage occupies approximately 45-

60% of sleep. In this stage, minor noises won’t disturb

you. Stage 2 is characterized by more mixed

brain wave activity with brief bursts of higher-frequency brain waves, called sleep spindles.

Stage Two

Theta Waves

Stages 3 & 4 are "Delta" sleep or "slow wave" sleep

and may last 15-30 minutes. Stage 3, breathing and pulse have slowed down Stage 4 is a very deep sleep.

By the time we reach stage 4, we are about 1 hour into sleep.

It is called "slow wave" sleep because brain activity slows down dramatically from the "theta" rhythm of Stage 2 to a much slower rhythm called delta waves.

Stage Three & Four

Contrary to popular belief, it is delta

sleep that is the "deepest" stage of sleep (not REM).

In children, delta sleep can occupy up to 40% of all sleep time This is what makes children unawakeable

or "dead asleep" during most of the night.

Stage Three and Four (continued)

After reaching the deepest sleep stage (4), the sleep

cycle starts moving backward towards stage 1. Once stage 1 should be next in line in the cycle, something

interesting happens…rapid eye movement (REM) sleep begins.

From REM, you go back to Stage 2, and the cycle repeats itself.

We will have a REM period about every 90 minutes from the time we fall asleep until morning.

Each REM period lasts longer than the previous one (our longest one might be around 30 – 40 minutes long).

Stage 5: REM Sleep

Although still asleep, the brain engages in low-

amplitude, fast and regular beta waves, much like in the awake-aroused state.

Stage 5: REM Sleep (cont.)

REM sleep is characterized by an EEG that looks awake and alert…and by rapidly moving eyes behind the lids, an irregular (and increased) pulse and breathing rate, and loss of muscle tone.

More information about REM Sleep

REM composes 20-25% of a normal night’s sleep. When someone is awakened from REM sleep, they report

vivid dreaming. 37% of people report rarely or never having “dreams” Even those who claim they never dream will, more

than 80% of the time dream, recall a dream after being awakened during REM sleep

More information about REM

Sleep

The body is essentially paralyzed during REM. During REM, our bodies are in a state of paralysis

Have you ever tried to run away in a dream and found you couldn’t move? That’s because you couldn’t move your legs – literally!

Any part of the sleep cycle when we are not in REM sleep is referred to as NREM sleep (non-rapid eye movement sleep).

During non-REM sleep, the brain is still active, providing partial thoughts, images, and stories, but they do not have the organization of the “stories” found during REM activity. Some researchers think that NREM sleep is the time

when the body rests.

Fig. 5-4, p. 179

Figure 5.4: EEG patterns in sleep and wakefulness. Characteristic brain waves vary depending on one’s state of consciousness. Generally, as people move from an awake state through deeper stages of sleep, their brain waves decrease in frequency (cycles per second) and increase in amplitude (height). However, brain waves during REM sleep resemble “wide-awake” brain waves.

The Sleepytime Bedtime Calculator calculates the optimal time for you to fall asleep so that you don’t wake up in the middle of a 90-minute sleep cycle: http://www.stumbleupon.com/su/1Ihd4K/sleepyti.me

EEG Sleep Stage

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We spend one-third of

our lives sleeping. The exact function of

sleep is uncertain, but sleep appears to provide time for the body to carry out important functions. If an individual remains

awake for several days, immune function and concentration deteriorates and the risk of accidents increases.

Why do we sleep?

Sleep Theories

1. Sleep Protects: Sleeping in the darkness when predators loomed about kept our ancestors out of harm’s way.

2. Sleep Helps us Recover: Sleep helps us recuperate and restores the breakdown of our body. It helps restore and repair brain tissue and eliminate waste products from muscles.

3. Sleep Helps us Remember: Sleep restores and rebuilds our fading memories.

4. Sleep may play a role in the growth process: During sleep, the pituitary gland releases growth hormone. Older people release less of this hormone and sleep less.

So if sleep is important for all of these So if sleep is important for all of these reasons, what happens if we don’t get reasons, what happens if we don’t get

enough?enough?

We all need different amounts of sleep depending

on our __________ and ______________. But we ALL sleep – about 25 years on average.

2/3 of Americans get less than 8 hours Newborns 16-18 hours Elderly 5 hours American students average 6 hours

Adolescents typically need 10 hours Linked to lower grades

How Much Sleep Do We Need?

Fig. 5-7, p. 182

Figure 5.7: Cultural variations in how long people tend to sleep. A recent study (Soldatos et al., 2005) surveyed over 35,000 people in 10 countries about various aspects of their sleep habits. This graph shows the average duration of nighttime sleep reported by the respondents in each country. Although Japan was a bit of an “outlier,” the cultural differences are rather modest. Cultural variability in the average time required to fall asleep was also modest. Consistent with previous findings, the results of this study suggest that the basic architecture of sleep does not vary much across cultures. (Data from Soldatos et al., 2005)

Many students “drag themselves through high school & college like walking zombies… moody, lethargic, and unprepared or unable to learn”

James Maas (sleep researcher) **Video: Inside the Teenage Brain

Sleep Deprivation vs. Sleep

Restriction

Long-Term Sleep Deprivation• Impaired concentration.• Emotional irritability.• Depressed immune system.• Fatigue and subsequent

death.

Sleep Deprivation vs. Sleep Restriction

Sleep restriction: or partial deprivation, occurs when people make do with less sleep than normal. This can cause negative effects,

particularly in performance, with long-lasting, difficult, or monotonous tasks (which can be very, very costly).– The nuclear accident at Three Mile

Island, the space shuttle Challenger explosion, the Chernobyl nuclear power plant explosion, and the Exxon Valdez oil spill off the coast of Alaska were all disasters caused in part by sleep deprivation on the part of workers.

– ARTICLE

Likelihood of traffic & work accidents increases Tired truck drivers 1500 road deaths per year Driver fatigue causes more accidents than alcohol

or other drugs

We may not be piloting a large oil tanker or building a spaceship, but we still face our own dangers that come along with

sleep restriction…

Studies show that sleep deprived drivers are just as dangerous, if not more so, than drunk drivers. Teenagers are at an even greater risk of accidents. See why here: Video Link

Hormone levels necessary for normal muscle development & proper immune system functioning decline

Mental flexibility, attention, & creativity all decline Nelson B. Powell, MD, DDS, who was the head of a sleep

deprivation and reaction time study found that on all seven measures, the group of sleep deprived subject results were worse than those of the drinking group at a blood alcohol level of 0.057 percent. And on three measures, the apnea patients scored as badly or worse than the drinkers who were legally drunk. "That really stunned us," Powell said.

Brain cells can become impaired or damaged

Hallucinations & delusions Higher rate of infections

Other Consequences of Getting Too Little Sleep

Are you sleep deprived?

Table 3.1Myers: Psychology, Ninth EditionCopyright © 2010 by Worth Publishers

Step 1

Add up the number of hours' sleep you've had over the last week from Monday to Friday. Don't include the weekend.

Step 2Think about a day when you felt alert and at your peak. How many hours of sleep did you get the night before? If you are not sure, put eight hours. Multiply that number by five.

Step 3Subtract the number in Step 2 from the number in Step 1.

The number you are left with is your sleep debt. If it's positive or zero, your sleep account is in the black!

"The good news is that it is easy to pay back a sleep debt. Depending on how much in debt you may be, two nights of at least eight hours of deep sleep should get you back into balance."

To calculate your sleep debt…