module 8
how does sleep overtake us?
consciousness fades as different parts of our brain's cortex stop communicating YET the sleeping brain remains active and has its own biological rhythm
What do we dream, and what functions have theorists proposed for dreams?
"We usually dream of ordinary events and everyday experiences, most involving some anxiety or misfortune. Fewer than 10 percent of dreams among men (and fewer still among women) have any sexual content. Most dreams occur during REM sleep; those that happen during NREM sleep tend to be vague fleeting images. There are five major views of the function of dreams. (1) Freud's wish-fulfillment: Dreams provide a psychic "safety valve," with manifest content (story line) acting as a censored version of latent content (underlying meaning that gratifies our unconscious wishes). (2) Information-processing: Dreams help us sort out the day's events and consolidate them in memory. (3) Physiological function: Regular brain stimulation may help develop and preserve neural pathways in the brain. (4) Neural activation: The brain attempts to make sense of neural static by weaving it into a story line. (5) Cognitive development: Dreams reflect the dreamers' level of development—their knowledge and understanding. Most sleep theorists agree that REM sleep and its associated dreams serve an important function, as shown by the REM rebound that occurs following REM deprivation in humans and other species." Excerpt From: David Myers. "Psychology in Modules." Apple Books.
what five theories propose explanations for why we dream?
(1) Freud's wish-fulfillment (dreams as a psychic safety valve), (2) information-processing (dreams sort the day's events and consolidate memories), (3) physiological function (dreams pave neural pathways), (4) activation-synthesis (REM sleep triggers random neural activity that the mind weaves into stories), and (5) cognitive development (dreams reflect the dreamer's developmental stage)
After about age 20
(slightly earlier for women), we begin to shift from being owls to being larks (Roenneberg et al., 2004). Women become more morning oriented as they have children and also as they transition to menopause (Leonhard & Randler, 2009; Randler & Bausback, 2010).
what are five proposed reasons for our need for sleep
1- sleep has survival value 2- sleep help us restore the immune system and repair brain tissue 3- during sleep we consolidate memories 4- sleep fuels creativity 5- sleep plays a role in the growth process
So, our sleep patterns differ from person to person and from culture to culture. But why do we have this need for sleep? Psychologists offer five possible reasons:
1- sleep protect 2- sleep helps up recuperate 3-Sleep helps restore and rebuild our fading memories of the day's experiences. 4-Sleep feeds creative thinking 5-Sleep supports growth
how much time does it take us to " cycle through distinct sleep stages"?
90 minutes
Sleep across the life span
As we age, our sleep patterns change. During our first few months, we spend progressively less time in REM sleep. During our first 20 years, we spend progressively less time asleep. (Data from Snyder & Scott, 1972.)
Freud's wish-fulfillment
Dreams provide a "psychic safety valve"—expressing otherwise unacceptable feelings; contain manifest (remembered) content and a deeper layer of latent content (a hidden meaning). Critical Considerations:Lacks any scientific support; dreams may be interpreted in many different ways.
to reflect cognitive development
Some dream researchers prefer to see dreams as part of brain maturation and cognitive development (Domhoff, 2010, 2011; Foulkes, 1999). For example, prior to age 9, children's dreams seem more like a slide show and less like an active story in which the dreamer is an actor. Dreams overlap with waking cognition and feature coherent speech. They simulate reality by drawing on our concepts and knowledge. They engage brain networks that also are active during daydreaming—and so may be viewed as intensified mind wandering, enhanced by visual imagery (Fox et al., 2013). Unlike the idea that dreams arise from bottom-up brain activation, the cognitive perspective emphasizes our mind's top-down control of our dream content (Nir & Tononi, 2010). Dreams, says G. William Domhoff (2014), "dramatize our wishes, fears, concerns, and interests in striking scenarios that we experience as real events."
Less sleep = more accidents
On the Monday after the spring time change, when people lose one hour of sleep, accidents increased, as compared with the Monday before. In the fall, traffic accidents normally increase because of greater snow, ice, and darkness, but they diminished after the time change.
A circadian disadvantage
One study of more than 24,000 Major League Baseball games found that teams who had crossed three time zones before playing a series had nearly a 60 percent chance of losing their first game
Activation-synthesis
REM sleep triggers neural activity that evokes random visual memories, which our sleeping brain weaves into stories. Critical Considerations:The individual's brain is weaving the stories, which still tells us something about the dreamer
what are the 4 stages, and in what order do we normally travel through those stages?
REM, NREM-1, NREM-2, NREM-3; normally we move though NREM-1, then NREM-2, then NREM-3, then back up thought NREM-2, before we experience REM sleep
About an hour after you first fall asleep, a strange thing happens
Rather than continuing in deep slumber, you ascend from your initial sleep dive. Returning through NREM-2 (where you'll ultimately spend about half your night), you enter the most intriguing of the four sleep phases—REM sleep (FIGURE 8.4). For about 10 minutes, your brain waves become rapid and saw-toothed, more like those of the nearly awake NREM-1 sleep. But unlike NREM-1, during REM sleep your heart rate rises, your breathing becomes rapid and irregular, and every half-minute or so your closed eyes dart around in momentary bursts of activity. These eye movements announce the beginning of a dream—often emotional, usually story-like, and richly hallucinatory. Dreams aren't real, but REM sleep tricks your brain into responding as if you are actually watching a real scene (Andrillon et al., 2015). because anyone watching a sleeper's eyes can notice these REM bursts, it is amazing that science was ignorant of REM sleep until 1952.
Physiological function
Regular brain stimulation from REM sleep may help develop and preserve neural pathways. Critical Considerations:This does not explain why we experience meaningful dreams.
when people were getting ready to sleep for sleep analysis
a researcher comes in and tapes electrodes to your scalp (to detect your brain waves), on your chin (to detect muscle tension), and just outside the corners of your eyes (to detect eye movement; FIGURE 8.1). Other devices will record your heart rate, respiration rate, and genital arousal.
dreams
a sequence of images, emotions, and thoughts passing through a sleeping person's mind.
night terrors
a sleep disorder characterized by high arousal and an appearance of being terrified; unlike nightmares, night terrors occur during NREM-3 sleep, within two or three hours of falling asleep, and are seldom remembered. effect:Doubling of a child's heart and breathing rates during the attack. Luckily, children remember little or nothing of the fearful event the next day. As people age, night terrors become more and more rare.
sleep apnea
a sleep disorder characterized by temporary cessations of breathing during sleep and repeated momentary awakenings. effect:Fatigue and depression (as a result of slow-wave sleep deprivation). Associated with obesity (especially among men)
Narcolepsy
a sleep disorder characterized by uncontrollable sleep attacks. The sufferer may lapse directly into REM sleep, often at inopportune times. Risk of falling asleep at a dangerous moment. Narcolepsy attacks usually last less than 5 minutes, but they can happen at the worst and most emotional times. Everyday activities, such as driving, require extra caution.
REM sleep
rapid eye movement sleep; a recurring sleep stage during which vivid dreams commonly occur. Also known as paradoxical sleep, because the muscles are relaxed (except for minor twitches) but other body systems are active
what is REM sleep
rapid eye movement sleep; a recurring sleep stage during which vivid dreams commonly occur. Also known as paradoxical sleep, because the muscles are relaxed (except for minor twitches) but other body systems are active.
Freud considered dreams the key to
understanding our inner conflicts. However, his critics say it is time to wake up from Freud's dream theory, which they regard as a scientific nightmare. "There is no reason to believe any of Freud's specific claims about dreams and their purposes," observed dream researcher William Domhoff (2003).
Thinking and memory improve as
we approach our daily peak in circadian arousal.
What does yawning do?
which is also socially contagious, stretches your neck muscles and increases your heart rate, which increases your alertness
why would communal sleeping provide added protection for those safety depends upon vigilance
with each person cycling through the sleep stages independently it is very likely that any given Tim least one will be in an easily awakened stages in the event of the threat
What is the difference between narcolepsy and sleep apnea?
with narcolepsy, the personperiodicatly falls directly into REM sleep, with no warning ; with sleep apnea, the person repeatedly awakens during the night
is sleeping pattern cultural influenced?
yes
is sleeping pattern genetically influenced
yes
To catch your own hypnagogic experiences
you might use your alarm's snooze function.
Hallucinations
false sensory experiences, such as seeing something in the absence of an external visual stimulus.
during this brief NREM-1 sleep you may experience
fantastic images resembling hallucinations—sensory experiences that occur without a sensory stimulus. You may have a sensation of falling (at which moment your body may suddenly jerk) or of floating weightlessly.
NREM-1
fleeting images
major sleep disorders
insomnia, narcolepsy, sleep apnea, night terrors
circadian rhythm
our biological clock; regular bodily rhythms (for example, of temperature and wakefulness) that occur on a 24-hour cycle.
when you sleep, as when awake, you
process most information outside your conscious awareness.
a well-rested person would be more likely to have ---- (trouble concentrating/ quick reaction times) and a sleep-deprived person would be more likely to --- ( gain weight/ fight off cold)
quick reaction times; gain weight
Lack of sleep can also make you gain weight. Sleep deprivation
-increases ghrelin, a hunger-arousing hormone, and -decreases its hunger-suppressing partner, leptin (Shilsky et al., 2012). decreases metabolic rate, a gauge of energy use (Buxton et al., 2012). increases production of cortisol, a stress hormone that stimulates the body to make fat. enhances limbic brain responses to the mere sight of food and decreases cortical responses that help us resist temptation (Benedict et al., 2012; Greer et al., 2013; St-Onge et al., 2012).
ample sleep supports skill learning
A regular full night's sleep can "dramatically improve your athletic ability," report James Maas and Rebecca Robbins (2010). REM sleep and NREM-2 sleep—which occur mostly in the final hours of a long night's sleep—also help strengthen the neural connections that build enduring memories, including the "muscle memories" learned while practicing tennis or shooting baskets. Sleep promotes both a strong body and a strong mind. Well-rested athletes have faster reaction times, more energy, and greater endurance, and teams that build 8 to 10 hours of daily sleep into their training show improved performance. One study of Stanford University men's basketball players found that when their average sleep increased 110 minutes per night over the course of several weeks, their sprint times decreased, and their free throw and 3-point shooting percentages both increased 9 percent (Mah et al., 2011). Swimmer Conner Jaeger, who won a silver medal at the 2016 Olympics, takes sleep seriously. "Part of our training that we really just started to focus on," he said, "is sleep" (Mayberry, 2016). Maas, who has been a sleep consultant for college and professional athletes and teams, also advised basketball's Orlando Magic and figure skating's Sarah Hughes to cut their early-morning practices as part of a recommended sleep regimen. Soon thereafter, Hughes' performance scores increased, ultimately culminating in her 2002 Olympic gold medal. Given all the benefits of sleep, it's no wonder that sleep loss hits us so hard.
More commonly, a dream's story line incorporates traces of previous days' nonsexual experiences and preoccupations (De Koninck, 2000):
After suffering a trauma, people commonly report nightmares, which help extinguish daytime fears (Levin & Nielsen, 2007, 2009). One sample of Americans recording their dreams during September, 2001 reported an increase in threatening dreams following the 9/11 terrorist attacks (Propper et al., 2007). Compared with Palestinian children living in a peaceful town in Galilee, those living in the conflict-ridden Gaza Strip more often dream of aggression (Punamäki & Joustie, 1998). Compared with nonmusicians, musicians report twice as many dreams of music (Uga et al., 2006). Studies in four countries have found blind people mostly dreaming of using their nonvisual senses (Buquet, 1988; Taha, 1972; Vekassy, 1977). But even natively blind people sometimes "see" in their dreams (Bértolo, 2005). Likewise, people born paralyzed below the waist sometimes dream of walking, standing, running, or cycling (Saurat et al., 2011; Voss et al., 2011).
sleepwalking/sleeptalking
Doing normal waking activities (sitting up, walking, speaking) while asleep. Sleeptalking can occur during any sleep stage. Sleepwalking happens in NREM-3 sleep. effects:Few serious concerns. Sleepwalkers return to their beds on their own or with the help of a family member, rarely remembering their trip the next morning.
Cognitive development
Dream content reflects dreamers' level of cognitive development—their knowledge and understanding. Dreams simulate our lives, including worst-case scenarios. Critical Considerations:Does not propose an adaptive function of dreams.
Sleep feeds creative thinking
Dreams can inspire noteworthy artistic and scientific achievements, such as the dreams that clued chemist August Kekulé to the structure of benzene (Ross, 2006) and inspired medical researcher Carl Alving (2011) to invent the vaccine patch. More commonplace is the boost that a complete night's sleep gives to our thinking and learning. After working on a task, then sleeping on it, people solve difficult problems more insightfully than do those who stay awake (Barrett, 2011; Sio et al., 2013). They also are better at spotting connections among novel pieces of information (Ellenbogen et al., 2007; Whitehurst et al., 2016). To think smart and see connections, it often pays to ponder a problem just before bed and then sleep on it.
Information-processing
Dreams help us sort out the day's events and consolidate our memories Critical Considerations:But why do we sometimes dream about things we have not experienced and about past events?
Sleep supports growth
During slow-wave sleep, which occurs mostly in the first half of a night's sleep, the pituitary gland releases a growth hormone that is necessary for muscle development.
what does the EEG recorder show when a person is sleeping?
EEG recordings confirm that the brain's auditory cortex responds to sound stimuli even during sleep
the biological clock
Light striking the retina signals the suprachiasmatic nucleus (SCN) to suppress the pineal gland's production of the sleep hormone melatonin. At night, the SCN quiets down, allowing the pineal gland to release melatonin into the bloodstream.
You then relax more deeply and begin about 20 minutes of
NREM-2 sleep, with its periodic sleep spindles—bursts of rapid, rhythmic brain-wave activity. Although you could still be awakened without too much difficulty, you are now clearly asleep. Then you transition to the deep sleep of NREM-3. During this slow-wave sleep, which lasts for about 30 minutes, your brain emits large, slow delta waves and you are hard to awaken. (It is at the end of this stage that children may wet the bed.)
As the night progresses, what happens to the REM stage of sleep?
NREM-3
To make sense of neural static
Other theories propose that dreams erupt from neural activation spreading upward from the brainstem (Antrobus, 1991; Hobson, 2003, 2004, 2009). According to activation-synthesis theory,dreams are the brain's attempt to synthesize random neural activity. Much as a neurosurgeon can produce hallucinations by stimulating different parts of a patient's cortex, so can stimulation originating within the brain. As Freud might have expected, PET scans of sleeping people also reveal increased activity in the emotion-related limbic system (in the amygdala) during emotional dreams (Schwartz, 2012). In contrast, frontal lobe regions responsible for inhibition and logical thinking seem to idle, which may explain why our dreams are less inhibited than we are when awake (Maquet et al., 1996). Add the limbic system's emotional tone to the brain's visual bursts and—Voila!—we dream. Damage either the limbic system or the visual centers active during dreaming, and dreaming itself may be impaired (Domhoff, 2003).
How do biology and environment interact in our sleep patterns?
Our biology—our circadian rhythm as well as our age and our body's production of melatonin (influenced by the brain's suprachiasmatic nucleus)—interacts with cultural expectations and individual behaviors to determine our sleeping and waking patterns. Being bathed in (or deprived of) light disrupts our 24-hour biological clock; night-shift workers may experience chronic desynchronization
How do our biological rhythms influence our daily functioning?
Our bodies have an internal biological clock, roughly synchronized with the 24-hour cycle of night and day. This circadian rhythm appears in our daily patterns of body temperature, arousal, sleeping, and waking. Age and experience can alter these patterns, resetting our biological clock.
the tendency for REM sleep to increase following the REM sleep deprivation Is referred to as
REM rebound
How does sleep loss affect us, and what are the major sleep disorders?
Sleep deprivation causes fatigue and irritability, and it impairs concentration, productivity, and memory consolidation. It can also lead to depression, obesity, joint pain, a suppressed immune system, and slowed performance (with greater vulnerability to accidents). Sleep disorders include insomnia (recurring wakefulness); narcolepsy (sudden uncontrollable sleepiness, sometimes lapsing directly into REM sleep); sleep apnea (the repeated stopping of breathing while asleep; associated with obesity, especially in men); night terrors (high arousal and the appearance of being terrified; NREM-3 disorder found mainly in children); sleepwalking (NREM-3 disorder also found mainly in children); and sleeptalking
sleep help us recuperate
Sleep helps restore the immune system and repair brain tissue. Sleep gives resting neurons time to repair themselves, while pruning or weakening unused connections (Ding et al., 2016). Bats and other animals with high waking metabolism burn a lot of calories, producing free radicals, molecules that are toxic to neurons. Sleep sweeps away this toxic waste (Xie et al., 2013). Think of it this way: When consciousness leaves your house, workers come in to clean, saying "Good night. Sleep tidy."
what are sleep's functions?
Sleep may have played a protective role in human evolution by keeping people safe during potentially dangerous periods. Sleep also helps restore and repair damaged neurons. Sleep consolidates our memories by replaying recent learning and strengthening neural connections. Sleep promotes creative problem solving the next day. During slow-wave sleep, the pituitary gland secretes a growth hormone necessary for muscle development.
measuring sleep activity
Sleep researchers measure brain-wave activity, eye movements, and muscle tension with electrodes that pick up weak electrical signals from the brain, eyes, and facial muscles
Which of the following is NOT one of the reasons that have been proposed to explain why we need sleep?
Sleep rests the eyes.
a dreamy take on dreamland
The 2010 movie Inception creatively played off our interest in finding meaning in our dreams, and in understanding the layers of our consciousness. It further explored the idea of creating false memories through the power of suggestion.
example of sleeping debt
The U.S. Navy and the National Institutes of Health have demonstrated the benefits of unrestricted sleep in experiments in which volunteers spent 14 hours daily in bed for at least a week. For the first few days, the volunteers averaged 12 hours of sleep or more per day, apparently paying off a sleep debt that averaged 25 to 30 hours. That accomplished, they then settled back to 7.5 to 9 hours nightly and felt energized and happier (Dement, 1999).
REM sleep is thus sometimes called paradoxical sleep
The body is internally aroused, with waking-like brain activity, yet asleep and externally calm.
the stages in typical night's sleep
Then you transition to the deep sleep of NREM-3. During this slow-wave sleep, which lasts for about 30 minutes, your brain emits large, slow delta waves and you are hard to awaken. (It is at the end of this stage that children may wet the bed.)
Dream theorists have proposed several explanations of why we dream, including these:
To satisfy our own wishes In 1900, in his landmark book The Interpretation of Dreams, Sigmund Freud offered what he thought was "the most valuable of all the discoveries it has been my good fortune to make." He proposed that dreams provide a psychic safety valve that discharges otherwise unacceptable feelings. He viewed a dream's manifest content (the apparent and remembered story line) as a censored, symbolic version of its latent content, the unconscious drives and wishes (often erotic) that would be threatening if expressed directly. Thus, a gun might be a disguised representation of a penis.
leep helps restore and rebuild our fading memories of the day's experiences.
To sleep is to strengthen. Sleep consolidates our memories by replaying recent learning and strengthening neural connections (Pace-Schott et al., 2015; Yang et al., 2014). It reactivates recent experiences stored in the hippocampus and shifts them for permanent storage elsewhere in the cortex (Racsmány et al., 2010; Urbain et al., 2016). Adults, children, and infants trained to perform tasks therefore recall them better after a night's sleep, or even after a short nap, than after several hours awake (Friedrich et al., 2015; Seehagen et al., 2015). Older adults' more frequently disrupted sleep also disrupts memory consolidation (Boyce et al., 2016; Pace-Schott & Spencer, 2011). After sleeping well, older people remember more of recently learned material (Drummond, 2010). Sleep, it seems, strengthens memories in a way that being awake does not.
the moment of sleep
We seem unaware of the moment we fall into sleep, but someone eavesdropping on our brain waves could tell.
sleep protects
When darkness shut down the day's hunting, gathering, and travel, our distant ancestors were better off asleep in a cave, out of harm's way. Those who didn't wander around dark cliffs were more likely to leave descendants. This fits a broader principle: A species' sleep pattern tends to suit its ecological niche (Siegel, 2009). Animals with the greatest need to graze and the least ability to hide tend to sleep less. Animals also sleep less, with no ill effects, during times of mating and migration (Siegel, 2012).
what did William dement observe
William Dement (1999) observed the moment the brain's perceptual window to the outside world slammed shut. Dement asked a sleep-deprived young man with eyelids taped open to press a button every time a strobe light flashed in his eyes (about every 6 seconds). After a few minutes the young man missed one. Asked why, he said, "Because there was no flash." But there was a flash. He missed it because (as his brain activity revealed) he had fallen asleep for 2 seconds, missing not only the flash 6 inches from his nose but also the awareness of the abrupt moment of entry into sleep.
animal sleep time
Would you rather be a brown bat and sleep 20 hours a day or a giraffe and sleep 2 hours a day?
What is the biological rhythm of our sleeping and dreaming stages?
Younger adults cycle through four distinct sleep stages about every 90 minutes. (The sleep cycle repeats more frequently for
Night-shift workers may experience
a chronic state of desynchronization. As a result, they become more likely to develop fatigue, stomach problems, heart disease, and, for women, breast cancer
What is sleep?
as distinct from unconsciousness resulting from a coma, general anesthesia, or hibernation. (Adapted from Dement, 1999.) it is the irresistible tempter to whom we inevitably succumb
manifest content
according to Freud, the remembered story line of a dream (as distinct from its latent, or hidden, content).
latent content
according to Freud, the underlying meaning of a dream (as distinct from its manifest content).
what does age and experience do to our sleep
age and experience can alter our circadian rhythm
as morning nears
body temperature rises
the SCN does its job partly by
causing the brain's pineal gland to decrease its production of the sleep-inducing hormone melatonin in the morning and to increase it in the evening
Our body temperature tends to rise and fall in sync with a biological clock, which is referred to as __________.
circadian rhythm
How sleep deprivation affects us: brain
decreased ability to focus attention and process and store memories; increased risk of depression; decreased metabolic rate; increased cortisol; enhanced limbic brain responses to the mere sight of food ; decreased cortical response-reducing ability to resist temptation
How sleep deprivation affects us: immure system
decreased production of immune cells; increased risk of viral infections. such as colds
Moreover, REM sleep's processing of emotional experiences helps protect against
depression
Sleep loss is also a predictor of
depression
when the temperature of the body peaks
during the day
when the temperature of the body dips after the peak
early afternoon
the rhythm of the day parallels the rhythm of life
from our waking at a new day's birth to our nightly return to what Shakespeare called "death's counterfeit." Our bodies roughly synchronize with the 24-hour cycle of day and night thanks to an internal biological clock called the circadian rhythm (from the Latin circa, "about," and diem,"day").
Except during very scary dreams, your
genitals become aroused during REM sleep. You have an erection or increased vaginal lubrication and clitoral engorgement, regardless of whether the dream's content is sexual
when you pull an all nighter you will feel
groggiest in the middle of the night but may gain new alertness when your normal wake-up time arrives.
During the NREM-1 sleep stage, a person is most likely to experience
hallucinations.
Brain scans confirm the link between REM sleep and memory.
he brain regions that were active as rats learned to navigate a maze, or as people learned to perform a visual-discrimination task, became active again later during REM sleep (Louie & Wilson, 2001; Maquet, 2001). So precise were these activity patterns that scientists could tell where in the maze the rat would be if awake.
how did this fact of sleep stages come to life
his fact came to light when 8-year-old Armond Aserinsky went to bed one night in 1952. His father, Eugene, a University of Chicago graduate student, needed to test an electroencephalograph machine he had repaired that day (Aserinsky, 1988; Seligman & Yellen, 1987). Placing electrodes near Armond's eyes to record the rolling eye movements then believed to occur during sleep, Aserinsky watched the machine go wild, tracing deep zigzags on the graph paper. Could the machine still be broken? As the night proceeded and the activity recurred, Aserinsky realized that the periods of fast, jerky eye movements were accompanied by energetic brain activity. Awakened during one such episode, Armond reported having a dream. Aserinsky had discovered what we now know as REM sleep (rapid eye movement sleep).
Morning types tend to do better in
in school, take more initiative, be more punctual, and be less vulnerable to depression
These hypnagogic sensations may later be
incorporated into your memories.
AS the night progresses, what happens to the REM stage of sleep?
increase in duration
How sleep deprivation affects us: stomach
increased in hinger-arousing gherkin; decrease in hunger- suppressing leptin
How sleep deprivation affects us: joints
increased inflammation and arthritis
How sleep deprivation affects us: fat cells
increased production; greater risk of obesity
How sleep deprivation affects us: heart
increased risk of high blood pressure
In interpreting dreams, Freud was most interested in their
latent content, or hidden meaning.
given that our ancestors' body clocks were attuned to the rising and setting Sun of the 24-hour day
many of today's young adults adopt something closer to a 25-hour day, by staying up too late to get 8 hours of sleep. For this, we can thank (or blame) Thomas Edison, inventor of the light bulb. Approximately 90 percent of Americans report using a light-emitting electronic device one hour before going to sleep (Chang et al., 2015). Such artificial light delays sleep.
NREM-3
minimal awareness
Sleep deprivation can suppress
mmune cells that battle viral infections and cancer
Discovering the link between REM sleep and dreaming began
new era in dream research Instead of relying on someone's hazy recall hours after having a dream, researchers could catch dreams as they happened. They could awaken people during or within 3 minutes after a REM sleep period and hear a vivid account.
Biological and psychological explanations of behavior are
not competitors.
During REM sleep, your brain's motor cortex is active, but
our brainstem blocks its messages. which causes our uscles relaxed, so much so that, except for an occasional finger, toe, or facial twitch, you are essentially paralyzed. Moreover, you cannot easily be awakened. (This immobility may occasionally linger as you awaken from REM sleep, producing a disturbing experience of sleep paralysis
To develop and preserve neural pathways
perhaps dreams, or the brain activity associated with REM sleep, serve a physiological function, providing the sleeping brain with periodic stimulation. This theory makes developmental sense. Stimulating experiences preserve and expand the brain's neural pathways. Infants, whose neural networks are fast developing, spend much of their abundant sleep time in REM sleep
Sleep deprivation slows
reactions and increases errors on visual attention tasks similar to those involved in screening airport baggage, performing surgery, and reading X-rays (Caldwell, 2012; Lim & Dinges, 2010). Slow responses can also spell disaster for those operating equipment, piloting, or driving. Drowsy driving has contributed to an estimated one in six American traffic accidents (AAA, 2010) and to some 30 percent of Australian highway deaths (Maas, 1999).
insomnia
recurring problems in falling or staying asleep. effect:Chronic tiredness. Reliance on sleeping pills and alcohol, which reduce REM sleep and lead to tolerance—a state in which increasing doses are needed to produce an effect.
How sleep deprivation affects us: muscles
reduced strength ; slower reaction time and motor learning
To file away memories The information-processingperspective proposes that dreams may help
sift, sort, and fix the day's experiences in our memory. Some studies support this view. When tested the day after learning a task, those who had been deprived of both slow-wave and REM sleep did not do as well as those who had slept undisturbed (Stickgold, 2012). Other studies showed similar memory lapses for new material among people who were awakened every time they began REM sleep (Empson & Clarke, 1970; Karni & Sagi, 1994).
This link does not appear to reflect an effect of depression on
sleep
in general, night owls tend to be
smart and creative
Dreams are a fascinating altered
state of consciousness.
Sleep often eludes those who
stay up late and sleep in on weekends, and then go to bed earlier on Sunday evening in preparation for the new workweek
REM
story-like dream
the ----- nucleus helps monitor the brain's release of melatonin, which affect our---- rhythm
suprachiasmatic , circadian
Tiredness triggers
testiness
How has activation-synthesis been used to explain why we dream?
the activation-synthesis thoery suggests that dreams are the brain's attempt[t to make sense of the random neural activity
Brain Waves and Sleep Stages
the beta waves of an alert, waking state and the regular alpha waves of an awake, relaxed state differ from the slower, larger delta waves of deep NREM-3 sleep. Although the rapid REM sleep waves resemble the near-waking NREM-1 sleep waves, the body is more aroused during REM sleep than during NREM sleep
How has activation-synthesis been used to explain why we dream? "For what one has dwelt on by day, these things are seen in visions of the night" (Menander of Athens, Fragments). How might we use the information-processing perspective on dreaming to interpret this ancient Greek quote?
the information- processing explanation of dreaming pro-poses that brain activity during REM sleep enables us to sift through the daily events and activities we have been thinking about
delta waves
the large, slow brain waves associated with deep sleep
Men's common "morning erection" stems from
the night's last REM period, often just before waking
when you are in bed and you close your eyes the researcher in the next room sees on the EEG
the relatively slow alpha waves of your awake but relaxed state As you adapt to all this equipment, you grow tired and, in an unremembered moment, slip into sleep . This transition is marked by the slowed breathing and the irregular brain waves of non-REM stage 1 sleep. Using the American Academy of Sleep Medicine classification of sleep stages, this is called NREM-1
alpha waves
the relatively slow brain waves of a relaxed, awake state
REM rebound
the tendency for REM sleep to increase following REM sleep deprivation
The sleep cycle repeats itself about every 90 minutes for
younger adults (with shorter, more frequent cycles for older adults). As the night goes on, deep NREM-3 sleep grows shorter and disappears, and REM and NREM-2 sleep periods get longer (see Figure 8.4). By morning, we have spent 20 to 25 percent of an average night's sleep—some 100 minutes—in REM sleep. In sleep lab studies, 37 percent of participants have reported rarely or never having dreams that they "can remember the next morning" (Moore, 2004). Yet even they, more than 80 percent of the time, could recall a dream after being awakened during REM sleep. We spend about 600 hours a year experiencing some 1500 dreams, or more than 100,000 dreams over a typical lifetime—dreams swallowed by the night but not acted out, thanks to REM's protective paralysis.
Some Natural Sleep Aids
• Exercise regularly but not in the late evening. (Late afternoon is best.) • Avoid caffeine after early afternoon, and avoid food and drink near bedtime. The exception would be a glass of milk, which provides raw materials for the manufacture of serotonin, a neurotransmitter that facilitates sleep. • Relax before bedtime, using dimmer light. • Sleep on a regular schedule (rise at the same time even after a restless night) and avoid long naps. • Hide time displays so you aren't tempted to check repeatedly. • Reassure yourself that temporary sleep loss causes no great harm. • Focus your mind on nonarousing, engaging thoughts, such as song lyrics or vacation travel (Gellis et al., 2013). • If all else fails, settle for less sleep, either going to bed later or getting up earlier.