sleep research what do psychologists who conduct sleep research measure during their studies?
TRANSCRIPT
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…