Brain Activity During Sleep: Myth of Brain Rest - Prof. Robert Gordon, Study notes of Psychology

Download Brain Activity During Sleep: Myth of Brain Rest - Prof. Robert Gordon and more Study notes Psychology in PDF only on Docsity! 1 Psychology 110 Dr. Gordon Module #17 “States of Consciousness” “Waking and Sleeping Rhythms” A. Waking consciousness • 1. Levels of consciousness • 2. Daydreams and fantasies 1. L ev el s o f c on sc io us ne ss • Myers defines consciousness as “our awareness of ourselves and our environment.” This particular concept has had a “stormy” history in the field of psychology. In James’ “Principles of Psychology,” he proposed that consciousness was like a stream that flowed and wandered aimlessly at times. If one could tape record one’s thoughts, one would find an endless flow of ideas. William James 2 1. L ev el s o f c on sc io us ne ss • Freud proposed that consciousness existed on different levels of awareness. These levels included the consciousness, preconsciousness, and unconscious. According to Freud, the critical level is the unconscious. It is defined as a level of awareness that is not immediately accessible. It is the root of all neuroses and conflict. Sigmund Freud 1. L ev el s o f c on sc io us ne ss • Freud supporters believed that levels of awareness were analogous to an iceberg. That is, the tip of the iceberg represented the conscious. The unconscious and preconscious represented the part of the iceberg that was vast but unseen and unknown. In the Freud view, the conscious level matters the least. 1. L ev el s o f c on sc io us ne ss • During most of the 20th century, our focus on consciousness was the minority view. It was not until brain technologies emerged that consciousness again became a focus of study. In response to stimuli, scientists observed changes in brain wave activity. Brain researchers noted that different levels of consciousness corresponded to different patterns of brain activity. Beta wave activity suggests an active brain and full alertness. 5 True • “All living things have circadian or 24 hour rhythm. This affects us when we feel sleepy and when we feel alert. Light and dark cycles set these circadian rhythms. When you travel across time zones, your circadian rhythm adjusts when the light and dark cycle changes. For a shift worker, the light and dark cycle does not change, so the circadian rhythm never adjusts. Whether you work the night shift or not, you are most likely to feel sleepy between midnight and six in the morning. And no matter how many years you work a night shift, sleeping during the day remains difficult. Shift workers should avoid caffeine during the last half of the day, block out noise and light at bedtime, and stay away from alcohol and alerting activities before bed. “ (USA Today, March, 1999) 1. T he h um an b od y ne ve r a dj us ts to n ig ht sh ift w or k? • The slide above illustrates the circadian rhythm for three bodily functions. These functions include growth hormone release, body temperature, and alertness. The graph above shows that growth hormone release actually increases during sleep. 1. T he h um an b od y ne ve r a dj us ts to n ig ht sh ift w or k? • Besides the graveyard shift, transcontinental flight can play havoc with our circadian rhythms. The experience of jet lag is a common experience among those traveling across time zones. There are two ways of looking at jet lag; eastward or westward. 6 1. T he h um an b od y ne ve r a dj us ts to n ig ht sh ift w or k? • Studies have shown that bright light helps “reset our biological clocks.” When traveling, researchers have identified two types of “light” shifts that affect our circadian rhythms. A phase delay shift is when we extend our daylight by traveling westward. A phase advance shift is when we shorten our daylight by traveling eastward. It takes longer for one to fall asleep after a phase advance shift because of lack of light. 1. T he h um an b od y ne ve r a dj us ts to n ig ht sh ift w or k? • The slide above illustrates that even workers are more satisfied when placed on a phase delay shift that involves increasing the amount of light in one’s day. Improvement was greater for workers who had more time to adjust to each change in shifts. Let’s take a look at the next film clip that reveals the dynamics of circadian rhythms. 2. D ur in g sle ep , y ou r b ra in re sts ? • Researchers have examined neural activity during sleep.As noted by Myers, neural activity during sleep was discovered by accident. A Chicago University graduate student, Eugene Aserinsky placed an EEG electrode underneath the eyes of his sleeping son, Armond. Did Aserinsky find an inactive brain during sleep? 7 False • While your body rests, your brain does not. An active brain during sleep prepares you for alertness and peak functioning the next day. (USA Today, March 1999). 2. D ur in g sle ep , y ou r b ra in re sts ? • Our understanding of the brain’s activity during thesleep has been conducted in sleep laboratories across the country. In addition to an EEG, sleep researchers use electromyograph (EMG) and electrooculograph (EOG). The EMG measures muscle activity. The EOG records eye movements. 2. D ur in g sle ep , y ou r b ra in re sts ? • Sleep researchershave identified different sleep stages. Each stage has its own unique brain wave activity. Stages 1-4 are considered NonREM sleep (i.e., absence of any eye movements). We all begin sleep in a relaxed or alpha wave state. We begin to feel drowsy. Sleep Stages 10 2. D ur in g sle ep , y ou r b ra in re sts ? • Sleep researchers haveidentified changes in the body during REM sleep. First, one experiences rapid and irregular breathing. Second, the eyes move rapidly underneath the eyelids. Third, in males, one can experience a penile erection, whereas, females experience increased vaginal lubrication and clitoral engorgement. For males, REM sleep is often indicates whether one’s erectile dysfunction is physical or psychogenic. REM sleep 2. D ur in g sle ep , y ou r b ra in re sts ? • Sleep researchers haveidentified changes in the body during REM sleep. First, one experiences rapid and irregular breathing. Second, the eyes move rapidly underneath the eyelids. Third, in males, one can experience a penile erection, whereas, females experience increased vaginal lubrication and clitoral engorgement. For males, REM sleep often indicates whether one’s erectile dysfunction is physical or psychogenic. REM sleep 2. D ur in g sle ep , y ou r b ra in re sts ? • During the REM state, thesleeper is paralyzed from the neck down despite brain activity in motor cortex. The REM state has been called paradoxical sleep because internally the body is aroused but externally it appears to be at peace. Lastly, REM sleep has been associated with persons reporting dream states. Unlike the sensory images of “Stage 1” sleep, REM dreams are frequently emotional, storylike, and accessible. Because the individual experiences paralysis during REM sleep, one is unable to act out their dreams. The humorous side of REM sleep 11 2. D ur in g sle ep , y ou r b ra in re sts ? • REM sleep hasbeen discovered in other species. For example, the cats spend nearly 80 percent of their day sleeping. To the right, a cat is currently in a NonREM stage of sleep. The meticulous observer knows this because the cat is upright. A cat during NonREM 2. D ur in g sle ep , y ou r b ra in re sts ? • However, thesame cat progresses to a REM state of sleep. One can observe the temporary state of paralysis by the cat’s limp muscles and body flopped to the side. The relaxed muscles and paralysis explains why we do not act out our dreams. A cat during REM 3. T he o ld er y ou g et , t he fe we r ho ur s o f s le ep y ou n ee d? • Does sleep need vary with age? Do older people require more sleep than teenagers, infants, etc…? Sleep need has always been controversial issue. Most sleep researchers argue that any individual variation in need can be attributed to genetics, temperament. If any age differences exist, they are probably related to sleep efficiency. Do older persons need More sleep? 12 False • Sleep need remains unchanged throughout adulthood. Older people may wake more frequently through the night and may sleep less, but their sleep need is no less than during young adulthood. Sleep difficulties are not a normal part of aging although they are all too common. However, as we age, we get less slow wave delta sleep. What are the implications? 3. T he o ld er y ou g et , t he fe we r ho ur s o f s le ep y ou n ee d? • Do infants require more sleep than adults? The need for sleep does not necessarily change but sleep patterns do change. For example, infants, on the average, sleep about 16 hours a day but with 6 to 8 two hour intervals. At birth, infants do display greater percentage of rem sleep (50%). By the end of the first year, infants spend about 30% of their time in rem sleep. Newborns are in REM sleep 50 percent of the time. 3. T he o ld er y ou g et , t he fe we r ho ur s o f s le ep y ou n ee d? • For adults, there is a gradual shift toward lighter sleep. Adults spend less time in rem (20%) and stage 3/4 delta wave deep sleep. They also spend more time in stage 1 sleep. It is not unusal for adults to experience more frequent awakenings during the night. However, the need remains the same from young to older adulthood. Adults are not always the most efficient sleepers. 15 4. Y ou c an no t l ea rn to fu nc tio n no rm al ly w ith o ne o r t wo fe we r h ou rs o f sle ep a n ig ht th an y ou n ee d? • What about REM deprivation? One variation of sleep research is to deprive subjects of REM sleep. As a result, researchers observed a greater frequency of REM periods after prolonged deprivation. After returning to normal sleep, subjects often reported a “REM rebound effect.” That is, they spent more time in REM if deprived of it over time. 4. Y ou c an no t l ea rn to fu nc tio n no rm al ly w ith o ne o r t wo fe we r h ou rs o f sle ep a n ig ht th an y ou n ee d? • Sleep deprivation studies raise an important issue, why do we need sleep? What is real function of sleep? According to Myers, sleep serves three functions. These are protection (early in our evolution it was not adaptive to function in the dark), restoration (brain repair), and growth (during sleep growth hormone is released). Sleep deprivation can be costly! Sleep basically feeds our brain. 4. Y ou c an no t l ea rn to fu nc tio n no rm al ly w ith o ne o r t wo fe we r h ou rs o f sle ep a n ig ht th an y ou n ee d? • Can you wake without an alarm clock? If you scored three true statements, you are likely deprived! 16 5. R ai sin g th e vo lu m e of y ou r r ad io w ill he lp y ou st ay a wa ke w hi le d riv in g? • Partial sleep deprivation has been linked to car accidents. Drivers drink coffee, take stimulant drugs, talk to passengers, and turn up their radios just to stay awake. Do these things really work? Myers notes that 20 percent of car accidents can be attributed to partial sleep deprivation. False • If you are having trouble staying awake while driving, the only short-term solution is to pull over at a safe place and take a short nap or have a caffeinated drink. The only long-term solution is prevention--- starting out well rested after a good night’s sleep. Research shows that loud radios, chewing gum and open windows fail to keep sleepy drivers alert (USA Today, 1999). 6. Resting in bed with your eyes closed cannot satisfy your body’s need for sleep? • As long as persons are resting, could they be satisfying the need to sleep? 17 False • Sleep is as necessary to health as food and water, and rest is no substitute for sleep. Sleep is an active process needed for health and alertness. When you do not get the sleep you need, your body builds up a sleep debt. Sooner or later, the debt must be paid with sleep. 7. Most people do not know when they are sleepy? • This particular driver may not really know that he is sleeping? This might explain why people wonder why their car is in a ditch and have no idea how it happened. True • Researchers have asked thousands of people over the years if they are sleepy, only to be told no---just before the people fall asleep. What does this mean? Many people do not know whether they are sleepy, when they are sleepy, or why they are sleepy. When driving, do not think you can tough it out when you are sleepy even if you are only a few miles from your destination. If you are sleepy enough, you can fall alseep anywhere. 20 9. S le ep in g di so rd er s a re m ai nl y du e to w or ry o r p sy ch ol og ic al p ro bl em s? • Kale and others’ studies have shown that persons with sleeping problems such as insomnia tend to experience more presleep negative thoughts and feelings than noninsomniacs. Insomnia has also caught the attention of animators. 9. S le ep in g di so rd er s a re m ai nl y du e to w or ry o r p sy ch ol og ic al p ro bl em s? • Sleep researchers have identified other sleep disorders. These include: narcolepsy, nightmares, night terrors, and sleep walking or somnambulism. Night terrors and nightmares are especially a problem for children. Night terrors are a NonREM disorder. Whereas nightmares are a REM disorder. Night Terror or Nightmare? 9. S le ep in g di so rd er s a re m ai nl y du e to w or ry o r p sy ch ol og ic al p ro bl em s? • Night terrors can be described as a state of intense disorientation. The person, typically a child, wakes up feeling terrified in cold sweat. Night terrors usually occur in stage 4 about 2 to 3 hours into the sleep cycle. Nightmares are a REM disorder. Nightmares are associated with neurotic symptoms of neurosis in adults. In children, nightmares of high frequency and intensity are associated with emotional disturbance. 21 9. S le ep in g di so rd er s a re m ai nl y du e to w or ry o r p sy ch ol og ic al p ro bl em s? • Like night terrors, sleepwalking is more common in children. It is a NonREM disorder observed during stage 4 of the sleep cycle. With age, sleep walking tends to decrease because less time is spent in stage 4 of the sleep cycle. Sleepwalkers do not usually hurt themselves and return to bed on their own or with family assistance. Furthermore, sleepwalkers cannot recall anything about their walking incidents. A young teenager receives hypnotic treatment for her sleepwalking problems. 9. S le ep in g di so rd er s a re m ai nl y du e to w or ry o r p sy ch ol og ic al p ro bl em s? • Narcolepsy is a rare sleep disorder that affects 1 in 2000 persons. Narcolepsy stems from the absence of a neurotransmitter called hypocretin, a peptide produced in the hypothalamus. Research indicates that malfunctions in the activity of the small brain peptides, known as either hypocretins (HO), interfere with the sleep-wake cycle. Narcolepsy is clearly linked to problems in the brain. However, this link is yet to be found in human beings. 9. S le ep in g di so rd er s a re m ai nl y du e to w or ry o r p sy ch ol og ic al p ro bl em s? • Researchers recently found that Dobermans and Labrador retrievers with narcolepsy have a defective gene that impairs hypocretin activity. Nevertheless, finding the same gene has been problematic in human research. In the meantime, narcolepsy continues to be a dangerous sleep disorder because it can strike at any time. It can be especially hazardous if a person is driving. A narcolepsy gene was first discovered in Doberman Pinchers 22 10. Snoring is not harmful as long as it does not disturb others or wake you up? • Is snoring a condition that we not worry about or does it suggest serious health problems? False • Snoring may indicate the presence of a life-threatening sleep disorder called sleep apnea. People with sleep apnea snore loudly and awaken repeatedly during the night gasping for breath. There is effective treatment; physicians and sleep specialists should be consulted (USA Today, 1999). 10 . S no rin g is no t h ar m fu l a s l on g as it do es n ot d ist ur b ot he rs o r w ak e yo u up ? • According to sleep researchers, 1 in 20 persons are affected by sleep apnea. Sleep apnea involves frequent, reflexive gasping for air that awakens a person and disrupts sleep. Sleep apnea occurs mostly in men during their middle aged years, who are overweight and smoke. The individual may awaken numerous times (nearly 400) over the course of the night causing significant sleep loss. Most persons suffering from sleep apnea are not aware of having the condition. Individuals who are overweight are at risk for sleep apnea. As obesity cases increase, sleep apnea also increases. 25 11 . E ve ry on e d re am s n ig ht ly ? • Dream content may stemfrom our previous day’s experiences. For example, Dement and colleagues found a link between one’s dream and what happens during one’s day. In one experiment, while in REM sleep, subjects’ hands were sprayed with water. As a result, 42 percent of subjects reported water in their dream. They dreamt about swimming, floods, baths, rainfall, etc... William Dement 11 . E ve ry on e d re am s n ig ht ly ? • What about dreams andculture? Dreams may not have as much significance in western societies as they do other cultures. Nonetheless, some sleep researchers claim that dreams may have historical significance or impact social change. Dreams mean different things to western and nonwestern cultures. For western cultures, dreams do not play a major role in people’s lives. However, in nonwestern cultures dreams play a central role in one’s life. In nonwestern cultures, dreams have major significance. 11. Everyone dreams nightly? • Even though dreams may not hold as much significance in western cultures, they do get the attention of humorists. “The golden arches!” “The golden arches got me!” 26 11 . E ve ry on e d re am s n ig ht ly ? • Why do we dream? A number of theories explaining dreams have been proposed. These include: Freud’s wish fulfillment, Cartwright’s problems solving, and synthesis activation theories. 11 . E ve ry on e d re am s n ig ht ly ? • Why do we dream? A number of theories have been proposed. These include Freud’s notion of wish fulfillment, problem solving or information processing theory, and synthesis activation theory. Let’s take a look at Freud’s theory. Freud believe that dreams were the ultimate road to one’s unconscious mind. Freud believed that all dreams are “traced back by analysis to erotic wishes.” Lets take a look at a humorous clip that implies Freud’s notion of dreams and wish fulfillment. Sigmund Freud proposed that dreams function to satisfy our erotic wishes. 11 . E ve ry on e d re am s n ig ht ly ? • Freud proposed that dreams consisted of two types of content. These included manifest and latent dream content. The manifest content is what a person basically remembers from their dream. The manifest content is a superficial version of one’s dream storyline. The latent content is the underlying meaning of the dream. Freud proposed that dreams were a product of the unconscious. If waking life was ungratified, dreams provided an outlet for satisfaction. If one were sexually frustrated by day, nightly dreams about erotic experiences allowed for satisfaction. The mailman is a part of the manifest content. 27 11. Everyone dreams nightly? • Cartwright proposed that dreams provide a means to solving daily problems . dreams help one to restore a sense of competence. Only limited support has been found for this theory. 11 . E ve ry on e d re am s n ig ht ly ? • Activation synthesis theory proposes that dreams aresimply the by-product of bursts of neural activity coming from subcortical areas in the brain. Neurons fire in lower brain centers are synthesized by higher brain centers to make sense out of signals.