Chapter 10. Biological Rhythms and Sleep
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Mo Costandi Scientists have learned how to discover what you are dreaming about while you sleep. A team of researchers led by Yukiyasu Kamitani of the ATR Computational Neuroscience Laboratories in Kyoto, Japan, used functional neuroimaging to scan the brains of three people as they slept, simultaneously recording their brain waves using electroencephalography (EEG). The researchers woke the participants whenever they detected the pattern of brain waves associated with sleep onset, asked them what they had just dreamed about, and then asked them to go back to sleep. This was done in three-hour blocks, and repeated between seven and ten times, on different days, for each participant. During each block, participants were woken up ten times per hour. Each volunteer reported having visual dreams six or seven times every hour, giving the researchers a total of around 200 dream reports. Most of the dreams reflected everyday experiences, but some contained unusual content, such as talking to a famous actor. The researchers extracted key words from the participants’ verbal reports, and picked 20 categories — such as 'car', 'male', 'female', and 'computer' — that appeared most frequently in their dream reports. Kamitani and his colleagues then selected photos representing each category, scanned the participants’ brains again while they viewed the images, and compared brain activity patterns with those recorded just before the participants were woken up. © 2012 Nature Publishing Group
Mo Costandi A disturbed night's sleep might signal a future diagnosis of Alzheimer’s disease, according to findings presented this week at the annual meeting of the Society for Neuroscience in New Orleans, Louisiana. Patients with Alzheimer’s often complain of changes in their sleep patterns during the early stages of the disease. In healthy people, for example, daytime naps usually last around 20 minutes, but they can be to 3 hours long in patients with Alzheimer’s disease. Roxanne Sterniczuk, a neurophysiologist at Dalhousie University in Halifax, Canada, and her colleagues wanted to determine how early these changes occur and if they could predict a person’s future risk of developing the disease. Sterniczuk and her colleagues analysed data from around 14,600 healthy people, collected as part of the Survey of Health, Ageing and Retirement in Europe (SHARE), a long-term observational study of people aged 50 and over from 12 European countries. They looked at various measures of sleep quality, and used them to produce a ‘sleep disturbance index’. The researchers found that participants who reported sleeping restlessly, feeling tired during the day and taking sleep medication were more likely to be diagnosed with Alzheimer’s within the next 2 years, and that the greater the extent of these problems, the more severe were the symptoms of the subsequent disease. “Increased daytime sleepiness was the biggest predictor,” says Sterniczuk. “It would appear that subtle changes in the sleep–wake cycle are taking place before any disease pathology.” © 2012 Nature Publishing Group
by Jessica Hamzelou Never underestimate the value of a good night's sleep. Not only does a lack of shut-eye leave you irritable, it has been linked to diabetes and weight gain, though no one understood why. To investigate, Matthew Brady at the University of Chicago and his colleagues tested fat cells taken from the bellies of seven adults after four nights of sleeping up to 8 and a half hours, and then again after four nights on a measly 4 and a half hours. The team found that after sleep deprivation fat cells from the same person were on average 30 per cent less responsive to insulin – a hormone that makes muscle, liver and fat cells take up glucose after a meal. High blood glucose levels are linked to diabetes. Fat cells also normally release the appetite-regulating hormone leptin. Brady suggests that if sleep-deprived cells are generally malfunctioning, this mechanism may also be disrupted, affecting weight gain. "We were surprised at how robust the response was," says Brady. "Four nights of sleep curtailment represents a real-world situation, such as sitting for final exams or having a newborn in the house." Journal reference: Annals of Internal Medicine, DOI: 10.7326/0003-4819-157-8-201210160-00005 © Copyright Reed Business Information Ltd.
There was nothing sweet about Kaitlyn Terrana's 16th birthday. And she has virtually no recollection of her last birthday, her 17th, either. She slept through both of them. At a time when the teenager should be living each day to the fullest, she is trapped in a roughly six-week cycle in which she has no choice but to take to her bed, slumbering for about 10 days at a time. Kaitlyn has developed an extremely rare condition called Kleine-Levin syndrome, or KLS, and it is stealing her life away. "Kind of like the day before, I start feeling really tired and it's really hard for me to focus in class," she says from her home in Winona, Ont., near Hamilton. "And then after that, I'm just gone for 10 days. I have to sleep, I can't stay awake." Her mom, Kathy Terrana, has to closely monitor Kaitlyn when she experiences one of these sleeping periods, saying her daughter can't be left alone. "In the beginning of her episodes, she starts off being very, very tired," she says. "By late evening I can usually tell that, yes, she is starting an episode, because she doesn't talk, she doesn't converse with anybody. "It's not very nice to say, but it's almost like she's a walking zombie, because when they're in their episodes they can be walking around but they don't know what's going on around them. So there's no empathy, there's no feeling whatsoever. She's in a complete fog." © CBC 2012
Link ID: 17348 - Posted: 10.09.2012
By Scicurious Ok, I know it’s not Friday Weird Science time, but this paper is both interesting science AND somewhat odd. And who can’t use extra weird in their day, right? I know that Ed has already been here before me, but I can’t let this one go. I like studies on sleep, and I like studies on sex, and this has both! This paper is not actually about gettin’ laid. Though it IS about getting laid…but what it’s really about is the purpose of sleep. What is the purpose of sleep? After all, 8 hours a night (ish, for humans) is an awfully long time to spend unconscious and relatively defenseless. But almost all animals (all mammals and birds, definitely) that have more than a rudimentary brain do it. This leads us to think that it must really be an important thing to do. But why? There are several hypotheses as to why we need to sleep. The one I see most often is that our brains need that relatively inactive time (though there is still a lot of activity) to perform restorative processes and promote the best brain performance. But we don’t know, exactly, what the restorative processes are. We just know that animals and humans perform very badly on tasks when sleep deprived. But there is another hypothesis. This is the hypothesis that sleep is not really all that necessary for optimal performance. Instead, sleep is a way to preserve energy when it’s a better idea to be inactive. So, for example, humans might sleep at night because we’re at a disadvantage in the dark and would waste energy attempting activities. Support for this hypothesis comes from the fact that sleep needs vary massively across the animal kingdom. Some animals need 14 hours (see cats), while others need just 2-3. © 2012 Scientific American,
By James Gallagher Health and science reporter, BBC News Too many people may be damaging their health by self-medicating with sleeping pills, according to the Royal Pharmaceutical Society. It said half of people with insomnia diagnosed themselves and took medication without seeking medical advice. However, the society said insomnia was often part of other physical or mental health problems which needed treating. The warning was based on the findings of a survey of 2,077 people. Insomnia is difficulty in getting to sleep, staying asleep or getting enough good quality sleep night after night. One in three people in the UK are thought to have bouts of insomnia. It can be caused by psychiatric problems such as depression, anxiety disorders and schizophrenia. Other illnesses including heart disease, Alzheimer's disease and hormonal problems can also disturb the normal pattern of sleep. In the survey, 30% of people said they had taken sleeping pills for more than a month without getting advice while 14% had gone six months. One pharmacist, Paul Johnson, said: "It's worrying that so many people are overusing sleeping remedies. "They can be effective for short-term treatment of mild insomnia but should not be taken for long periods without advice because they can hide a serious health problem which could get worse if it remains untreated. BBC © 2012
Link ID: 17309 - Posted: 09.27.2012
By DAVID K. RANDALL SOMETIME in the dark stretch of the night it happens. Perhaps it’s the chime of an incoming text message. Or your iPhone screen lights up to alert you to a new e-mail. Or you find yourself staring at the ceiling, replaying the day in your head. Next thing you know, you’re out of bed and engaged with the world, once again ignoring the often quoted fact that eight straight hours of sleep is essential. Sound familiar? You’re not alone. Thanks in part to technology and its constant pinging and chiming, roughly 41 million people in the United States — nearly a third of all working adults — get six hours or fewer of sleep a night, according to a recent report from the Centers for Disease Control and Prevention. And sleep deprivation is an affliction that crosses economic lines. About 42 percent of workers in the mining industry are sleep-deprived, while about 27 percent of financial or insurance industry workers share the same complaint. Typically, mention of our ever increasing sleeplessness is followed by calls for earlier bedtimes and a longer night’s sleep. But this directive may be part of the problem. Rather than helping us to get more rest, the tyranny of the eight-hour block reinforces a narrow conception of sleep and how we should approach it. Some of the time we spend tossing and turning may even result from misconceptions about sleep and our bodily needs: in fact neither our bodies nor our brains are built for the roughly one-third of our lives that we spend in bed. © 2012 The New York Times Company
Link ID: 17292 - Posted: 09.25.2012
By MyHealthNewsDaily staff In common weight-loss advice, "get more sleep," should figure just as prominently as "eat less" and "move more," two researchers in Canada argue. There is strong evidence that lack of sleep is contributing to the obesity epidemic, they said, and factors that contribute to obesity that have been given less attention than diet and exercise may at least partly explain why weight-loss efforts fail, according to the researchers. "Among the behavioural factors that have been shown to impede weight loss, insufficient sleep is gaining attention and recognition," the researchers write in their editorial published today (Sept. 17) in the Canadian Medical Association Journal. The researchers pointed to a 2010 study in which participants were randomly assigned to sleep either 5.5 hours or 8.5 hours every night for 14 days. They all cut their daily calorie intake by 680 calories, and slept in a lab. Participants who slept for 5.5 hours lost 55 percent less body fat, and 60 percent more of their lean body mass than those who slept for longer. In other words, the sleep-deprived people held onto their fat tissue, and instead lost muscle. In another study, published in July, researchers looked at 245 women in a six-month weight loss program and found that those who slept more than seven hours a night, and those who reported better quality sleep, were 33 percent more likely to succeed in their weight-loss efforts. © 2012 NBCNews.com
Drivers who take certain antidepressants, anti-anxiety or sleeping pills could be at higher risk for motor vehicle collisions. Psychotropic drugs can impair a driver's ability to control a vehicle, but there's been less research on newer drugs used to treat insomnia. To learn more, researchers in Taiwan compared drug use among 5,183 people involved in motor vehicle accidents with a second group of 31,093 people of the same age and gender who went for outpatient care between 2000 and 2009. In Thursday's issue of the British Journal of Clinical Pharmacology, they concluded that those taking two types of antidepressants, sleep aids known as Z-drugs, and benzodiazepines used to treat anxiety and insomnia, face increased risk of motor vehicle accidents compared with people not taking those types of drugs. The antidepressants studied included selective serotonin re-uptake inhibitors or SSRIs like paroxitine or Paxil and fluoxetine or Prozac and tricyclic or TCA antidepressants such as amiptriptyline. "The findings underscore that subjects taking these psychotropic medications should pay increased attention to their driving performance in order to prevent …motor vehicle accidents," lead researcher Hui-Ju Tsai, of the National Health Research Institutes in Zhunan, Taiwan, and co-authors concluded. © CBC 2012
The U.S. national campaign to reduce the risk of sudden infant death syndrome has entered a new phase and will now encompass all sleep-related, sudden unexpected infant deaths, officials of the National Institutes of Health announced today. The campaign, which has been known as the Back to Sleep Campaign, has been renamed the Safe to Sleep Campaign. The NIH-led Back to Sleep Campaign began in 1994, to educate parents, caregivers, and health care providers about ways to reduce the risk of sudden infant death syndrome (SIDS). The campaign name was derived from the recommendation to place healthy infants on their backs to sleep, a practice proven to reduce SIDS risk. SIDS is the sudden death of an infant under 1 year of age that cannot be explained, even after a complete death scene investigation, autopsy, and review of the infant's health history. Sudden unexpected infant death (SUID) includes all unexpected infant deaths: those due to SIDS, and as well as those from other causes. Many SUID cases are due to such causes as accidental suffocation and entrapment, such as when an infant gets trapped between a mattress and a wall, or when bedding material presses on or wraps around an infant’s neck. In addition to stressing the placement of infants on their backs for all sleep times, the Safe to Sleep Campaign emphasizes other ways to provide a safe sleep environment for infants. This includes placing infants to sleep in their own safe sleep environment and not on an adult bed, without any soft bedding such as blankets or quilts. Safe to Sleep also emphasizes breast feeding infants when possible, which has been associated with reduced SIDS risk, and eliminating such risks to infant health as overheating, exposure to tobacco smoke, and a mother’s use of alcohol and illicit drugs.
Link ID: 17254 - Posted: 09.13.2012
By Elizabeth Quill Half a dozen times each night, your slumbering body performs a remarkable feat of coordination. During the deepest throes of sleep, the body’s support systems run on their own timetables. Nerve cells hum along in your brain, their chitchat generating slow waves that signal sleep’s nether stages. Yet, like buses and trains with overlapping routes but unsynchronized schedules, this neural conversation has little to say to your heart, which pumps blood to its own rhythm through the body’s arteries and veins. Air likewise skips into the nostrils and down the windpipe in seemingly random spits and spats. And muscle fluctuations that make the legs twitch come and go as if in a vacuum. Networks of muscles, of brain cells, of airways and lungs, of heart and vessels operate largely independently. Every couple of hours, though, in as little as 30 seconds, the barriers break down. Suddenly, there’s synchrony. All the disjointed activity of deep sleep starts to connect with its surroundings. Each network — run via the group effort of its own muscular, cellular and molecular players — joins the larger team. This change, marking the transition from deep to light sleep, has only recently been understood in detail — thanks to a new look at when and how the body’s myriad networks link up to form an übernetwork. © Society for Science & the Public 2000 - 2012
Link ID: 17235 - Posted: 09.10.2012
Problems sleeping may be an early sign of Alzheimer's if a study in mice also applies to people, say researchers. Clumps of protein, called plaques, in the brain are thought to be a key component of the illness. A study, published in the journal Science Translational Medicine, showed that when plaques first developed, the mice started having disrupted sleep. Alzheimer's Research UK argued that if the link was proven it could become a useful tool for doctors. The hunt for early hints that someone is developing Alzheimer's is thought to be crucial for treating the disease. People do not show problems with their memory or clarity of thought until very late on in the disease. At this point, parts of the brain will have been destroyed, meaning treatment will be very difficult or maybe even impossible. It is why researchers want to start early, years before the first symptoms. One large area of research is in plaques of beta amyloid which form on the brain. Levels of the beta amyloid protein naturally rise and fall over 24 hours in both mice and people. However, the protein forms permanent plaques in Alzheimer's disease. BBC © 2012
by Dennis Normile Are you a morning lark or a night owl? Scientists use that simplified categorization to explain that different people have different internal body clocks, commonly called circadian clocks. Sleep-wake cycles, digestive activities, and many other physiological processes are controlled by these clocks. In recent years, researchers have found that internal body clocks can also affect how patients react to drugs. For example, timing a course of chemotherapy to the internal body time of cancer patients can improve treatment efficacy and reduce side effects. But physicians have not been able to exploit these findings because determining internal body time is, well, time consuming. It's also cumbersome. The most established and reliable method requires taking blood samples from a patient hourly and tracking levels of the hormone melatonin, which previous research has tied closely to internal body time. Now a Japanese group has come up with an alternative method of determining internal body time by constructing what it calls a molecular timetable based on levels in blood samples of more than 50 metabolites—hormones and amino acids—that result from biological activity. The researchers established a molecular timetable based on samples from three subjects and validated it using the conventional melatonin measurement. They then used that timetable to determine the internal body times of other subjects by checking the levels of the metabolites in just two blood samples from each subject per day. © 2010 American Association for the Advancement of Science.
Keyword: Biological Rhythms
Link ID: 17211 - Posted: 08.28.2012
Mo Costandi It sounds like every student's dream: research published today in Nature Neuroscience shows that we can learn entirely new information while we snooze1. Anat Arzi of the Weizmann Institute of Science in Rehovot, Israel, and her colleagues used a simple form of learning called classical conditioning to teach 55 healthy participants to associate odours with sounds as they slept. They repeatedly exposed the sleeping participants to pleasant odours, such as deodorant and shampoo, and unpleasant odours such as rotting fish and meat, and played a specific sound to accompany each scent. It is well known that sleep has an important role in strengthening existing memories, and this conditioning was already known to alter sniffing behaviour in people who are awake. The subjects sniff strongly when they hear a tone associated with a pleasant smell, but only weakly in response to a tone associated with an unpleasant one. But the latest research shows that the sleep conditioning persists even after they wake up, causing them to sniff strongly or weakly on hearing the relevant tone — even if there was no odour. The participants were completely unaware that they had learned the relationship between smells and sounds. The effect was seen regardless of when the conditioning was done during the sleep cycle. However, the sniffing responses were slightly more pronounced in those participants who learned the association during the rapid eye movement (REM) stage, which typically occurs during the second half of a night's sleep. © 2012 Nature Publishing Group
By Christine Gorman More than 25 years later details of the attack are still shocking: Sometime after 2 A.M. one Sunday morning in May 1987, Kenneth James Parks, then 23, left his house in a Toronto suburb and drove 23 kilometers to the apartment of his wife's parents. He got out of the car, pulled a tire iron out of the trunk and let himself into the older couple's home with a key they had given him. Once inside, he struggled with and choked his father-in-law, Dennis Woods, until the older man fell unconscious and then struggled with and beat his mother-in-law, Barbara Ann Woods, stabbing her to death with a knife from her kitchen. Parks then got back into his car, drove to a nearby police station and announced to the startled officers on duty, "I think I have killed some people." For several hours before the Toronto man left his home, however, and throughout the course of the attack, Parks was asleep and therefore not criminally responsible for his actions, according to five doctors and the defense lawyer at his 1988trial for the murder of Barbara Ann and the attempted murder of Dennis. After deliberating for nine hours, the jury agreed and Parks was set free. Although prosecutors at the time considered the defense "ludicrous" and appealed the judge's decision to allow the jury to consider a sleepwalking defense, the Canadian Supreme court upheld the original ruling in 1992. Even the sleep specialist who was first brought in as a consultant on the case was initially skeptical that a sleepwalker could have undertaken such a series of complex behaviors—including safely driving through three traffic lights and portions of an express highway—before attacking anyone. After all, most people who strike out in their sleep usually injure themselves or the person sleeping next to them—not someone 23 kilometers away. But further examination showed that the tragedy was not, as it had first seemed, a clear-cut case of murder. © 2012 Scientific American,
By DOUGLAS QUENQUA Moleendo Stewart can’t say for sure what’s caused his lifelong sleeping problems. But he has his suspicions. There’s the childhood spent in loud, restless neighborhoods in Miami. “You hear people shooting guns all night, dealing drugs,” said Mr. Stewart, 41, who lives in the East Flatbush section of Brooklyn. He also cites his weight, 260 pounds, down from a peak of 310. Sleep experts would point to another factor working against Mr. Stewart: He is a black man. The idea that race or ethnicity might help determine how well people sleep is relatively new among sleep researchers. But in the few short years that epidemiologists, demographers and psychologists have been studying the link, they have repeatedly come to the same conclusion: In the United States, at least, sleep is not colorblind. Non-Hispanic whites get more and better-quality sleep than people of other races, studies repeatedly show. Blacks are the most likely to get shorter, more restless sleep. What researchers don’t yet know is why. “We’re not at a point where we can say for certain is it nature versus nurture, is it race or is it socioeconomics,” said Dr. Michael A. Grandner, a research associate with the Center for Sleep and Neurobiology at the University of Pennsylvania. But when it comes to sleep, “there is a unique factor of race we’re still trying to understand.” © 2012 The New York Times Company
Sleep apnea, a disorder characterized by snoring and daytime sleepiness that has been linked to cardiovascular disease, has primarily been viewed as a male problem, but a new Swedish study suggests the sleep disorder is also a common problem among women. Dr. Karl A Franklin of Umea University Hospital in Sweden and colleagues noted in the study released Wednesday that there have been only a few epidemiological studies conducted in women, and the frequency of the disorder in women "is still uncertain." Obstructive sleep apnea, in which a person has short pauses in breathing during sleep, may be caused by a temporary collapse of the airway. The gaps in breathing can last 10 to 30 seconds, and may occur dozens or hundreds of times each night. For their study, Franklin and the other Swedish researchers investigated 400 women from a population-based random sample of 10,000 women aged 20 to 70. The women answered a questionnaire and were monitored overnight. Obstructive sleep apnea was found in 50 per cent of the women subjects, with 14 per cent of them having a severe form of the disorder. Treatment for obstructive sleep apnea: For mild to moderate apnea, the best treatment is continuous positive airway pressure (CPAP). © CBC 2012
Link ID: 17170 - Posted: 08.16.2012
by Michael Marshall You may think you can cope without sleep, but you have nothing on male pectoral sandpipers. Some of these birds can go more than a fortnight with hardly any sleep – the most extreme case of uninduced sleep deprivation known in any animal. What's more, the males that sleep the least father the most offspring, suggesting they benefit from their lack of slumber. Pectoral sandpipers (Calidris melanotos) breed on the Arctic tundra of Asia and North America. Males don't help with childcare – instead they try to mate with as many females as possible. Bart Kempenaers of the Max Planck Institute for Ornithology in Seewiesen, Germany and colleagues fitted radio tags to 149 birds – accounting for most of a population living near Barrow in Alaska. This showed that males were highly active during periods when females were fertile. One male was active 95 per cent of the time for 19 days. The team then fitted 29 of the males with devices that recorded their brain activity, something never done before with a wild bird. This allowed them to look at the active males' sleep patterns. They found that the males that slept the least slept more deeply, but calculations show that this wouldn't make up for the sleep they missed, says team member Niels Rattenborg. © Copyright Reed Business Information Ltd
By Alyssa A. Botelho, Melanie Brunson, who has been blind since birth, suddenly awoke and found herself standing at 15th and K streets in Northwest Washington. She had stopped at the corner on her way home from work to await a safe time to cross and had dozed off. Even on awakening, she was so groggy she couldn’t focus well enough to hear passing cars and judge when it was safe to cross. The incident was a startling reminder of the sleep problems that had plagued her since birth. “Who knows how long I had been standing there,” she said. “I realized then that my safety was in jeopardy, and I began searching for remedies with a vengeance.” But years after that 2005 traffic scare and many subsequent visits to doctors and sleep clinics, Brunson still lies awake in bed night after night and then is desperately sleepy during the day. Although doctors have not definitively identified her disorder, researchers believe she suffers from non-24-hour sleep-wake disorder, or “non-24.” The chronic and little-known sleep condition is characterized by a body clock that is not aligned with a 24-hour day. Though non-24 can affect those with normal vision, it is especially prevalent among blind people who cannot sense light, the strongest environmental signal that synchronizes the brain’s internal sleep-wake pattern to the 24-hour cycle of the Earth day. © 1996-2012 The Washington Post
Shift workers are slightly more at risk of having a heart attack or stroke than day workers, research suggests. An analysis of studies involving more than 2m workers in the British Medical Journal said shift work can disrupt the body clock and have an adverse effect on lifestyle. It has previously been linked to an increased risk of high blood pressure and diabetes. Limiting night shifts would help workers cope, experts said. The team of researchers from Canada and Norway analysed 34 studies. In total, there were 17,359 coronary events of some kind, including cardiac arrests, 6,598 heart attacks and 1,854 strokes caused by lack of blood to the brain. These events were more common in shift workers than in other people. The BMJ study calculated that shift work was linked to a 23% increased risk of heart attack, 24% increased risk of coronary event and 5% increased risk of stroke. But they also said shift work was not linked to increased mortality rates from heart problems and that the relative risks associated with heart problems were "modest". The researchers took the socioeconomics status of the workers, their diet and general health into account in their findings. BBC © 2012