Biological Rhythms Biological rhythms are controlled by internal “biological clocks.” 1. Annual cycles / INFRADIAN: On an annual cycle, geese migrate, grizzly bears hibernate, and humans experience seasonal variations in appetite, sleep, and mood. Seasonal Affective Disorder (SAD) is a mood disorder people experience during dark winter months. OBJECTIVE 2| Distinguish four types of biological rhythms, and give and example of each.

Biological Rhythms 2. 28-day cycles / : The female menstrual cycle averages 28 days. Research shows menstruation may not affect moods. Infradian Rhythm – take place less than once a day, sometimes once a season / month.

Biological Rhythms 3. 24-hour cycles / CIRCADIAN RHYTHMS: Humans experience 24-hour cycles of varying alertness (sleep), body temperature, and growth hormone secretion. 4. 90-minute cycles / ULTRADIAN: We go through various stages of sleep in 90-minute cycles.

Rhythm of Sleep Circadian Rhythms occur on a 24-hour cycle and include sleep and wakefulness, which are disrupted during transcontinental flights. OBJECTIVE 3| Describe the cycle of our circadian rhythm, and identify some events that can disrupt this biological clock. Illustration © Cynthia Turner 2003 Light triggers the suprachiasmatic nucleus to decrease (morning) melatonin from the pineal gland and increase (evening) it at night fall.

How much do you know about sleep? The Revised Sleep and Dream Information Questionnaire

False. Normal REM sleep is accompanied by muscle paralysis that makes acting out of dreams impossible. Sleepwalking actually occurs in sleep stages 3 and 4. False. Night or sleep terrors (occurring in Stages 3 and 4) are marked by intense feelings of dread but lack the fearful narratives that characterize nightmares. Autonomic nervous system arousal is intense in night terrors but mild in nightmares. False. Because there is too little evidence to establish the usefulness of melatonin, the FDA has not approved it as a treatment for insomnia. Also, its long-term safety is uncertain. Evidence does suggest that melatonin helps some people with circadian rhythm disruptions. False. Research indicates that some hallucination like dreams occur in stage 1. Unlike REM dreams, these stage 1 dreams do not follow a narrative or story-line. False. Dreaming, as reported in self-reported dream logs, typically occurs in full color.

False. Infants enter REM sooner and for a greater percentage of sleep than do adults or older children. True. Some require as few as 4 hours while others need as many as 10. Most people require between 6 and 10 hours of sleep. True. Ninety-five percent of people awakened during REM report dreaming. Failure to report dreaming, suggest researchers, reflects a failure of memory. True. According to the 2005 Sleep in America poll, 54 percent of American adults report that, within the last year, they have experienced at least one or more symptoms of insomnia at least a few nights a week. False. Although the body rests during sleep, the brain is active and still controls body functions. More specifically, REM sleep is an active sleep during which dreams occur, breathing and heart rate increase and become irregular, and eyes move back and forth under the eyelids. Even in the deepest non-REM sleep, our minds still process information.

True. Sleep attacks, or persistent daytime sleepiness, is a common symptom of narcolepsy. False. Barbiturates suppress central nervous system activity and are associated with a lower level of REM sleep than is healthy. Moreover, they are highly addictive and are associated with painful and difficult withdrawal. Newer sleep medications (e.g., benzodiazepines) are much safer. False. Although generally safe, OTCs can cause nausea and, more rarely, fast or irregular heartbeat, blurred vision, and heightened sensitivity to sunlight. Because of the side effects of OTCs and because they are often ineffective in relieving sleep problems, experts generally advise against their use. Their primary ingredient is an antihistamine. False. Slow maturation of bladder control is the most common cause of bedwetting. Enuresis is viewed as a disorder of arousal, that is, an elevated sleep arousal threshold leaves the child unable to awaken after an enuretic episode.

True. Men over 50 are more likely to experience REM behavior disorder True. Men over 50 are more likely to experience REM behavior disorder. They may hurt themselves or their bed partners. About one-third of them develop Parkinson’s disease within three years of REM behavior disorder’s onset. False (or is it True?) Clearly there is disagreement on this one. The text cites evidence for the role of dreaming in memory consolidation. However, Palladino and Bloom cite Jerome Siegel’s review published in the November 2003 Scientific American that challenges the idea that REM sleep has a role in memory consolidation: “The findings that argue against memory consolidation include the demonstration that people who have brain damage that prevents REM sleep, or who have a drug induced blockade of REM sleep, have normal—or even improved—memory” (p. 96). True. Bigger animals—elephants, giraffes, humans—need less sleep than smaller animals— rats, cats, voles. The reason seems related to the fact that small animals have higher metabolic rates and higher brain and body temperatures than do large animals.

True. Placing infants on their backs has reduced sudden infant death syndrome by about 40 percent. True. Snoring can be a symptom of sleep apnea which is characterized by pauses in breathing during sleep. The difficult breathing leads to decreased blood oxygen, which increases the risk of cardiovascular disease The condition affects about 18 million adults in the United States and is most common among older, overweight men. True. Brain activity in fetuses is similar to that experienced by children and adults in REM. This activity is associated with facial muscle twitches and muscular tonicity, which would also be expected during REM sleep.

Are you sleep deprived? If you answer “true” to 3 or more of the 15 items you are probably not getting enough sleep.

Discussion Questions Describe your sleeping habits. On average, why don’t teens today get enough sleep? If you could plan how much and when you sleep, what would you plan and why At what times during the day do you feel most sleepy and most awake? Does your daily schedule capitalize on these periods of sleepiness and energy? Why or why not?

Sleep Stages Measuring sleep: About every 90 minutes, we pass through a cycle of five distinct sleep stages. OBJECTIVE 4| List the stages of sleep cycle, and explain how they differ. Hank Morgan/ Rainbow

Awake & Alert During strong mental engagement, the brain exhibits low amplitude and fast, irregular beta waves (15-30 cps). An awake person involved in a conversation shows beta activity. Beta Waves

Awake but Relaxed When an individual closes his eyes but remains awake, his brain activity slows down to a large amplitude and slow, regular alpha waves (9-14 cps). A meditating person exhibits an alpha brain activity.

Sleep Stages 1-2 During early, light sleep (stages 1-2) the brain enters a high-amplitude, slow, regular wave form called theta waves (5-8 cps). A person who is daydreaming shows theta activity. Theta Waves

Sleep Stages 3-4 During deepest sleep (stages 3-4), brain activity slows down. There are large-amplitude, slow delta waves (1.5-4 cps).

Stage 5: REM Sleep After reaching the deepest sleep stage (4), the sleep cycle starts moving backward towards stage 1. Although still asleep, the brain engages in low- amplitude, fast and regular beta waves (15-40 cps) much like awake-aroused state. A person during this sleep exhibits Rapid Eye Movements (REM) and reports vivid dreams.

90-Minute Cycles During Sleep With each 90-minute cycle, stage 4 sleep decreases and the duration of REM sleep increases.

How Long Can We Stay Awake? 264 hours or about 11 days. Randy Gardner, a 17-year-old high school student set this apparent world record for a science fair in 1965. Research participants in more carefully monitored experiments have stayed awake for 8 to 10 days. All showed progressive and significant deterioration in concentration, motivation, perception, and other higher mental processes as the sleep deprivation continued. Continous sleep deprivation in rats : The cause of death was associated with whole body hypermetabolism.

We spend one-third of our lives sleeping. Why do we sleep? We spend one-third of our lives sleeping. If an individual remains awake for several days, they deteriorate in terms of immune function, concentration, and accidents. OBJECTIVE 5| Explain why sleep patterns and duration vary from person to person. Jose Luis Pelaez, Inc./ Corbis

Sleep Deprivation Fatigue and subsequent death. Impaired concentration. Emotional irritability. Depressed immune system. Greater vulnerability. OBJECTIVE 6| Discuss several risks associated with sleep deprivation.

What happens when we don’t sleep? Increase in accidents: Exxon Valdez,, Union Carbide’s Bhopal, India, Three Mile Island & Chernobyl nuclear accidents all happened after midnight. Suppresses immune cells; alters metabolic & hormone functioning that mimic aging & increase chances of weight gain, hypertension & memory impairment; irritability, slowed performance, impaired creativity, concentration and communication

Frequency of accidents increase with loss of sleep

Afternoon Naps Afternoon siesta Americans: 1-2 per week 1/4 never nap 1/3 nap 4-5 per week

Napping Leonardo da Vinci – slept 90min/day in catnaps of 15 min every 4 hours. Salvador Dali – slept with a spoon in his hand Eidson, Churchill, President Johnson, President Clinton

Naps a sign of laziness or social artifact? Body’s cycle includes a period of sleep at night & smaller period in afternoon Isolated room tests 2 periods of sleep Longer at night Shorter during afternoon

I need my nap!! Babies develop habit Most people get drowsy 3-5 Corresponds to people’s drop in productivity

Stampi’s sleep experiment 30 min. nap intervals for 2 months Mood and alertness was good Objective performance dipped in 1st month but then rose above his pre-experiment performance.

Naps improve performance SciAm #13 Selective strategic naps is most important in dealing with sleep crises. – The Promise of Sleep by William Dement The longer the better 45min improved alertness for 6 hrs. 1 hr. improved alertness for 10 hrs.

Sleep Theories Sleep Protects: Sleeping in the darkness when predators loomed about kept our ancestors out of harm’s way. Sleep Recuperates: Sleep helps restore and repair brain tissue. Sleep Helps Remembering: Sleep restores and rebuilds our fading memories. Sleep and Growth: During sleep, the pituitary gland releases growth hormone. Older people release less of this hormone and sleep less. OBJECTIVE 7| Identify four theories of why we sleep.

Sleep Disorders: Insomnia Somnambulism: Sleepwalking. Nightmares: Frightening dreams that wake a sleeper from REM. Night terrors: Sudden arousal from sleep with intense fear accompanied by physiological reactions (e.g., rapid heart rate, perspiration) that occur during SWS. OBJECTIVE 8| Identify major sleep disorders.

Night Terrors & Sleep Walking These disorders occur primarily in children and typically disappear by adolescence Episodes occur in the first deep Stage 4 sleep of the night and are generally associated with body movements and intense autonomic activation. Brain-wave recordings indicate that both sleepwalkers and night terror victims are passing back and forth rapidly between sleep and wakefulness. Sleepwalking often occurs when people are very sleep deprived.

Sleep Disorders: Insomnia Narcolepsy: Overpowering urge to fall asleep that may occur while talking or standing up. Sleep apnea: Failure to breathe when asleep.

Dreams The link between REM sleep and dreaming has opened up a new era of dream research.

What do we Dream? Negative Emotional Content: 8 out of 10 dreams have negative emotional content. Failure Dreams: People commonly dream about failure, being attacked, pursued, rejected, or struck with misfortune. Sexual Dreams: Contrary to our thinking, sexual dreams are sparse. Sexual dreams in men are 1 in 10; and in women 1 in 30. Dreams of Gender: Women dream of men and women equally; men dream more about men than women. OBJECTIVE 9| Describe the most common content of dreams.

Why do we dream? Wish Fulfillment: Sigmund Freud suggested that dreams provide a psychic safety valve to discharge unacceptable feelings. The dream’s manifest (apparent) content may also have symbolic meanings (latent content) that signify our unacceptable feelings. Information Processing: Dreams may help sift, sort, and fix a day’s experiences in our memories. OBJECTIVE 10| Compare the major perspectives on why we dream.

Why do we dream? Physiological Function: Dreams provide the sleeping brain with periodic stimulation to develop and preserve neural pathways. Neural networks of newborns are quickly developing; therefore, they need more sleep.

Why do we dream? Activation-Synthesis Theory: Suggests that the brain engages in a lot of random neural activity. Dreams make sense of this activity. Cognitive Development: Some researchers argue that we dream as a part of brain maturation and cognitive development. All dream researchers believe we need REM sleep. When deprived of REM sleep and then allowed to sleep, we show increased REM sleep called REM Rebound.

Dream Theories Summary