Links for Keyword: Sleep

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Patrick Fuller is a neuroscientist at Harvard Medical School's esteemed Division of Sleep Medicine. What have you found in your research on the "neurocircuit basis" that supports sleep? In specific reference to our recent work on the brainstem slow-wave-sleep promoter "center," we showed that this region of the brain is first connected (synaptically) to an important wake-promoting region of the brainstem that in turn is connected with important wake-promoting circuitry of the forebrain, which itself connects to the cerebral cortex. Essentially, we provided a circuit "wiring diagram" by which activation of brainstem sleep-promoting neurons might produce "whole brain" sleep. The reason I emphasize the word "neurocircuit" in our work is because I believe that in order to understand how the brain accomplishes virtually anything, one must first understand the functional cellular and synaptic "scaffolding" from which brain phenomena emerge. Tell me about how circadian regulation affects our sleep and wakeful consciousness. So it all starts (and ends!) with a little biological clock in our brain. The so-called "master" circadian clock is actually a collection of neurons located in a small region of the hypothalamus, itself a very small structure. (In humans, the hypothalamus is about the size of an almond.) This clock is remarkable for many reasons, perhaps most notably that no other region of the brain can assume its function if/when it is damaged. The clock's fundamental role is to keep us "synchronized" with the Earth's light-dark cycle as well as keep our body's internal rhythms synchronized with one another. And we now know that proper external and internal synchronization is fundamental to our physical and mental well-being. ©2015 TheHuffingtonPost.com, Inc.

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 20728 - Posted: 03.28.2015

By Nicholas Bakalar Sleeping more than eight hours a day is associated with a higher risk for stroke, a new study has found. Researchers studied 9,692 people, ages 42 to 81, who had never had a stroke. The study tracked how many hours a night the people slept at the beginning of the study and how much nightly sleep they were getting four years later. Over the 10-year study, 346 of the study subjects suffered strokes. After controlling for more than a dozen other health and behavioral variables, the researchers found that people who slept more than eight hours a day were 46 percent more likely to have had a stroke than those who slept six to eight hours. The study, published online last week in Neurology, also found that the risk of stroke was higher among people who reported that their need for sleep had increased over the study period. The authors caution that the data on sleep duration depended on self-reports, which can be unreliable. In addition, the study identified an association between sleep and stroke risk, rather than cause and effect. Sleeping more may be an early symptom of disease that leads to stroke, rather than a cause. “It could be that there’s already something happening in the brain that precedes the stroke risk and of which excessive sleep is an early sign,” said the lead author, Yue Leng, a doctoral candidate at the University of Cambridge. In any case, she added, “we don’t have enough evidence to apply this in clinical settings. We don’t want people to think if they sleep longer it will necessarily lead to stroke.” © 2015 The New York Times Company

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 19: Language and Hemispheric Asymmetry
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep; Chapter 15: Language and Our Divided Brain
Link ID: 20641 - Posted: 03.03.2015

Fatty liver disease, or the buildup of fat in the liver, and sleep apnea, marked by snoring and interruptions of breathing at night, share some things in common. The two conditions frequently strike people who are overweight or obese. Each afflicts tens of millions of Americans, and often the diseases go undiagnosed. Researchers used to believe that sleep apnea and fatty liver were essentially unrelated, even though they occur together in many patients. But now studies suggest that the two may be strongly linked, with sleep apnea directly exacerbating fatty liver. In a study published last year in the journal Chest, researchers looked at 226 obese middle-aged men and women who were referred to a clinic because they were suspected of having sleep apnea. They found that two-thirds had fatty liver disease, and that the severity of the disease increased with the severity of their sleep apnea. A study last year in The Journal of Pediatrics found a similar relationship in children. The researchers identified sleep apnea in 60 percent of young subjects with fatty liver disease. The worse their apnea episodes, the more likely they were to have fibrosis, or scarring of the liver. Though it is still somewhat unclear, some doctors suspect that the loss of oxygen from sleep apnea may increase chronic inflammation, which worsens fatty liver. Although fat in the liver can be innocuous at first, as inflammation sets in, the fat turns to scar tissue, and that can lead to liver failure. © 2015 The New York Times Company

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 20630 - Posted: 02.28.2015

The longer a teenager spends using electronic devices such as tablets and smartphones, the worse their sleep will be, a study of nearly 10,000 16- to 19-year-olds suggests. More than two hours of screen time after school was strongly linked to both delayed and shorter sleep. Almost all the teens from Norway said they used the devices shortly before going to bed. Many said they often got less than five hours sleep a night, BMJ Open reports. The teens were asked questions about their sleep routine on weekdays and at weekends, as well as how much screen time they clocked up outside school hours. On average, girls said they spent around five and a half hours a day watching TV or using computers, smartphones or other electronic devices. And boys spent slightly more time in front of a screen - around six and a half hours a day, on average. Playing computer games was more popular among the boys, whereas girls were more likely to spend their time chatting online. teen using a laptop Any type of screen use during the day and in the hour before bedtime appeared to disrupt sleep - making it more difficult for teenagers to nod off. And the more hours they spent on gadgets, the more disturbed their sleep became. When daytime screen use totalled four or more hours, teens had a 49% greater risk of taking longer than an hour to fall asleep. These teens also tended to get less than five hours of sleep per night. Sleep duration went steadily down as gadget use increased. © 2015 BBC

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep; Chapter 13: Memory, Learning, and Development
Link ID: 20543 - Posted: 02.03.2015

By James Gallagher Health editor, BBC News website The key to learning and memory in early life is a lengthy nap, say scientists. Trials with 216 babies up to 12 months old indicated they were unable to remember new tasks if they did not have a lengthy sleep soon afterwards. The University of Sheffield team suggested the best time to learn may be just before sleep and emphasised the importance of reading at bedtime. Experts said sleep may be much more important in early years than at other ages. People spend more of their time asleep as babies than at any other point in their lives. Yet the researchers, in Sheffield and Ruhr University Bochum, in Germany, say "strikingly little is known" about the role of sleep in the first year of life. Learn, sleep, repeat They taught six- to 12-month-olds three new tasks involving playing with hand puppets. Half the babies slept within four hours of learning, while the rest either had no sleep or napped for fewer than 30 minutes. The next day, the babies were encouraged to repeat what they had been taught. The results, published in Proceedings of the National Academy of Sciences, showed "sleeping like a baby" was vital for learning. On average one-and-a-half tasks could be repeated after having a substantial nap. Yet zero tasks could be repeated if there was little sleep time. Dr Jane Herbert, from the department of psychology at the University of Sheffield, told the BBC News website: "Those who sleep after learning learn well, those not sleeping don't learn at all." © 2015 BBC

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 17: Learning and Memory
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep; Chapter 13: Memory, Learning, and Development
Link ID: 20472 - Posted: 01.13.2015

By Nicholas Bakalar Planning to read in bed tonight? It may be better to read an actual book instead of an e-book reader. A small study has found that reading light-emitting electronic devices before bedtime is a recipe for poor sleep. Researchers randomly assigned 12 healthy young adults to one of two activities: reading a light-emitting e-book in a dimly lit room for about four hours before bedtime on five consecutive evenings, or reading a printed book for the same amount of time. All participants did both tasks. The researchers took blood samples to measure melatonin levels, and electronically tracked how long it took to fall asleep and how much time was spent in each sleep stage. The study, done at Brigham and Women’s Hospital in Boston, is online in the Proceedings of the National Academy of Sciences. Compared with a printed book, a light-emitting e-book decreased sleepiness, reduced REM sleep (often called dream sleep), and substantially suppressed the normal bedtime rise of melatonin, the hormone that regulates the sleep and wake cycle. The e-book users took longer to fall asleep and felt sleepier in the morning. “Much more has to be known about the kind of impact these devices have on our health and well-being,” said the lead author, Anne-Marie Chang, an assistant professor of biobehavioral health at Penn State. “The technology moves quickly, and the science lags.” © 2014 The New York Times Company

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 20436 - Posted: 12.23.2014

Kelly Servick* Anesthesiologists and surgeons who operate on children have been dogged by a growing fear—that being under anesthesia can permanently damage the developing brain. Although the few studies of children knocked out for surgeries have been inconclusive, evidence of impaired development in nematodes, zebrafish, rats, guinea pigs, pigs, and monkeys given common anesthetics has piled up in recent years. Now, the alarm is reaching a tipping point. “Anything that goes from [the roundworm] C. elegans to nonhuman primates, I've got to worry about,” Maria Freire, co-chair of the U.S. Food and Drug Administration (FDA) science advisory board, told attendees at a meeting the agency convened here last month to discuss the issue. The gathering came as anesthesia researchers and regulators consider several moves to address the concerns: a clinical trial of anesthetics in children, a consensus statement about their possible risks, and an FDA warning label on certain drugs. But each step stirs debate. Many involved in the issue are reluctant to make recommendations to parents and physicians based on animal data alone. At the same time, more direct studies of anesthesia's risks in children are plagued by confounding factors, lack of funding, and ethical issues. “We have to generate—very quickly—an action item, because I don't think the status quo is acceptable,” Freire said at the 19 November meeting. “Generating an action item without having the data is where things become very, very tricky.” © 2014 American Association for the Advancement of Science

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep; Chapter 13: Memory, Learning, and Development
Link ID: 20399 - Posted: 12.06.2014

By CATHERINE SAINT LOUIS Nearly 55 percent of infants nationwide are put to bed with soft blankets or covered by a comforter, even though such bedding raises the chances of suffocation or sudden infant death syndrome, federal researchers reported Monday. Their study, published in the journal Pediatrics, is the first to estimate how many infants sleep with potentially hazardous quilts, bean bags, blankets or pillows. Despite recommendations to avoid putting anything but a baby in a crib, two-thirds of black and Latino parents still use bedding that is both unnecessary and unsafe, the study also found. “I was startled a little bit by the number of people still using bedding in the sleep area,” said Dr. Michael Goodstein, a neonatologist in York, Pa., who serves on a task force on sleep-related infant deaths at the American Academy of Pediatrics. “Sleeping face down on soft bedding increases the risks of SIDS 21-fold.” Among the risk factors for SIDS, “bedding has fallen through the cracks,” said Dr. Thomas G. Keens, the chairman of the California SIDS Advisory Council. “This article is a wake-up call.” The new analysis looked at data gathered from 1993 to 2010 in the National Infant Sleep Position Study, which surveyed a random sample of nearly 19,000 parents by telephone. Use of infant bedding declined roughly 23 percent annually from 1993 to 2000. In recent years, however, the declines have slowed or stalled entirely. From 2001 to 2010, use of inappropriate bedding for white and Hispanic infants declined just 5 to 7 percent annually. There was no decline in the use of such bedding for black infants. Parents in the new study were not asked their reasons for using bedding. Previous research has found that they worry infants will be cold, or that the crib mattress is too hard. © 2014 The New York Times Company

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 20374 - Posted: 12.01.2014

More than 40 percent of infants in a group who died of sudden infant death syndrome (SIDS) were found to have an abnormality in a key part of the brain, researchers report. The abnormality affects the hippocampus, a brain area that influences such functions as breathing, heart rate, and body temperature, via its neurological connections to the brainstem. According to the researchers, supported by the National Institutes of Health, the abnormality was present more often in infants who died of SIDS than in infants whose deaths could be attributed to known causes. The researchers believe the abnormality may destabilize the brain’s control of breathing and heart rate patterns during sleep, or during the periodic brief arousals from sleep that occur throughout the night. “The new finding adds to a growing body of evidence that brain abnormalities may underlie many cases of sudden infant death syndrome,” said Marian Willinger, Ph.D, special assistant for SIDS at NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development, which funded the study. “The hope is that research efforts in this area eventually will provide the means to identify vulnerable infants so that we’ll be able to reduce their risk for SIDS.” SIDS is the sudden death of an infant younger than 1 year of age that is still unexplained after a complete post mortem investigation by a coroner or medical examiner. This investigation includes an autopsy, a review of the death scene, and review of family and medical histories. In the United States, SIDS is the leading cause of death between one month and one year of age. The deaths are associated with an infant’s sleep period.

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep; Chapter 13: Memory, Learning, and Development
Link ID: 20356 - Posted: 11.25.2014

By Dr. Catherine A. Madison “Now why did I walk into this room? Oh, yes, looking for my …” This scenario, familiar to many, is most often a sign of normal aging — or of having too much on our minds. But when these events seem to be happening frequently, is it a more serious problem, such as Alzheimer’s disease or another dementia? Even more importantly, are there good health habits that can help lower the risk of these neurodegenerative conditions? Research continues to demonstrate that healthy lifestyles lower one’s risk of developing cognitive decline later in life. Wise food choices and lots of exercise are a good base, along with learning new material and keeping socially connected. But another key element to brain health is good sleep. We may take sleep for granted, but research suggests this is not a passive process. There is a growing consensus that sleep is linked to learning, memory, nerve cell remodeling and repair. Evidence also suggests lack of sleep can contribute to mood and immune disorders, as well as to a decline in overall health. Most of us have read the dos and don’ts of good sleep hygiene: avoid napping, don’t drink alcohol or caffeine close to bedtime, avoid late-evening exercise and sleep in a room that is quiet, dark and cool. We’ve also been told about sleep cycles, in which we typically progress from light sleep early in the night to slow wave sleep with rapid eye movement, or REM, later on. We need a balance of sleep cycles for optimal health.

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep; Chapter 13: Memory, Learning, and Development
Link ID: 20293 - Posted: 11.10.2014

By Paula Span First, an acknowledgment: Insomnia bites. S. Bliss, a reader from Albuquerque, comments that even taking Ativan, he or she awakens at 4:30 a.m., can’t get back to sleep and suffers “a state of sleep deprivation and eventually a kind of walking exhaustion.” Molly from San Diego bemoans “confusion, anxiety, exhaustion, depression, loss of appetite, frankly a loss of will to go on,” all consequences of her sleeplessness. She memorably adds, “Give me Ambien or give me death.” Marciacornute reports that she’s turned to vodka (prompting another reader to wonder if Medicare will cover booze). After several rounds of similar laments here (and not only here; insomnia is prevalent among older adults), I found the results of a study by University of Chicago researchers particularly striking. What if people who report sleep problems are actually getting enough hours of sleep, overall? What if they’re not getting significantly less sleep than people who don’t complain of insomnia? Maybe there’s something else going on. It has always been difficult to ascertain how much people sleep; survey questions are unreliable (how can you tell when you’ve dozed off?), and wiring people with electrodes creates such an abnormal situation that the results may bear little resemblance to ordinary nightlife. Enter the actigraph, a wrist-motion monitor. “The machines have gotten better, smaller, less clunky and more reliable,” said Linda Waite, a sociologist and a co-author of the study. By having 727 older adults across the United States (average age: almost 72) wear actigraphs for three full days, Dr. Waite and her colleagues could tell when subjects were asleep and when they weren’t. Then they could compare their reported insomnia to their actual sleep patterns. Overall, in this random sample, taken from an ongoing national study of older adults, people didn’t appear sleep-deprived. They fell asleep at 10:27 p.m. on average, and awakened at 6:22 a.m. After subtracting wakeful periods during the night, they slept an average seven and a quarter hours. But averages don’t tell us much, so let’s look more closely at their reported insomnia. “What was surprising to us is that there’s very little association between people’s specific sleep problems and what the actigraph shows,” Dr. Waite said. © 2014 The New York Times Company

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep; Chapter 13: Memory, Learning, and Development
Link ID: 20250 - Posted: 10.28.2014

By Jane E. Brody Within a week of my grandsons’ first year in high school, getting enough sleep had already become an issue. Their concerned mother questioned whether lights out at midnight or 1 a.m. and awakening at 7 or 7:30 a.m. to get to school on time provided enough sleep for 14-year-olds to navigate a demanding school day. The boys, of course, said “yes,” especially since they could “catch up” by sleeping late on weekends. But the professional literature on the sleep needs of adolescents says otherwise. Few Americans these days get the hours of sleep optimal for their age, but experts agree that teenagers are more likely to fall short than anyone else. Researchers report that the average adolescent needs eight and a half to nine and a half hours of sleep each night. But in a poll taken in 2006 by the National Sleep Foundation, less than 20 percent reported getting that much rest on school nights. With the profusion of personal electronics, the current percentage is believed to be even worse. A study in Fairfax, Va., found that only 6 percent of children in the 10th grade and only 3 percent in the 12th grade get the recommended amount of sleep. Two in three teens were found to be severely sleep-deprived, losing two or more hours of sleep every night. The causes can be biological, behavioral or environmental. And the effect on the well-being of adolescents — on their health and academic potential — can be profound, according to a policy statement issued in August by the American Academy of Pediatrics. “Sleep is not optional. It’s a health imperative, like eating, breathing and physical activity,” Dr. Judith A. Owens, the statement’s lead author, said in an interview. “This is a huge issue for adolescents.” © 2014 The New York Times Company

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep; Chapter 13: Memory, Learning, and Development
Link ID: 20224 - Posted: 10.21.2014

By Benedict Carey Sleep. Parents crave it, but children and especially teenagers, need it. When educators and policymakers debate the relationship between sleep schedules and school performance and — given the constraints of buses, sports and everything else that seem so much more important — what they should do about it, they miss an intimate biological fact: Sleep is learning, of a very specific kind. Scientists now argue that a primary purpose of sleep is learning consolidation, separating the signal from the noise and flagging what is most valuable. School schedules change slowly, if at all, and the burden of helping teenagers get the sleep they need is squarely on parents. Can we help our children learn to exploit sleep as a learning tool (while getting enough of it)? Absolutely. There is research suggesting that different kinds of sleep can aid different kinds of learning, and by teaching “sleep study skills,” we can let our teenagers enjoy the sense that they’re gaming the system. Start with the basics. Sleep isn’t merely rest or downtime; the brain comes out to play when head meets pillow. A full night’s sleep includes a large dose of several distinct brain states, including REM sleep – when the brain flares with activity and dreams – and the netherworld of deep sleep, when it whispers to itself in a language that is barely audible. Each of these states developed to handle one kind of job, so getting sleep isn’t just something you “should do” or need. It’s far more: It’s your best friend when you want to get really good at something you’ve been working on. So you want to remember your Spanish vocabulary (or “How I Met Your Mother” trivia or Red Sox batting averages)? © 2014 The New York Times Company

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 17: Learning and Memory
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep; Chapter 13: Memory, Learning, and Development
Link ID: 20216 - Posted: 10.18.2014

By CATHERINE SAINT LOUIS Many cases of so-called crib death, about one in eight, occur among infants who have been placed on sofas, researchers reported on Monday. Dr. Jeffrey Colvin, a pediatrician at Children’s Mercy Hospital in Kansas City, Mo., and his colleagues analyzed data on 7,934 sudden infant deaths in 24 states, comparing those that occurred on sofas with those in cribs, bassinets or beds. Previous research had shown that couches were particularly hazardous for infants. The new analysis, published in the journal Pediatrics, tried to identify factors significant in these deaths. “It’s not only one risk that’s higher relative to other sleep environments,” said Barbara Ostfeld, a professor of pediatrics at Rutgers Robert Wood Johnson Medical School who was not involved in the new study. “It’s multiple risks.” Nearly three-quarters of the deaths occurred among infants age 3 months or younger, the researchers found. Pediatricians have long advised putting infants to sleep only on their backs, alone and on a firm, flat surface without a pillow. The new study found parents were more likely to lay their infants face down on a sofa than, for instance, face down in a crib. There’s a “fallacy that if I’m awake or watching, SIDS won’t happen,” Dr. Colvin said, referring to sudden infant death syndrome. © 2014 The New York Times Company

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 20197 - Posted: 10.13.2014

By CLAIRE MALDARELLI Whether it’s lying wide awake in the middle of the night or falling asleep at an international business meeting, many of us have experienced the funk of jet lag. New research has uncovered some of the mysteries behind how our cells work together to maintain one constant daily rhythm, offering the promise of defense against this disorienting travel companion. Many organisms, including humans and fruit flies, have pacemaker neurons — specialized cells in the brain that have their own molecular clocks and oscillate in 24-hour cycles. But in order for an organism to regulate itself, all of these internal clocks must tick together to create one master clock. While scientists understood how individual neurons set their own clock, they didn’t know how that master clock was set. Working with young fruit flies, whose neuronal system is simpler than adults with fewer cells and easier to study, the researchers found that two types of neurons, which they called dawn cells and dusk cells, maintain a continuous cycle. As the sun rises, special “timeless” proteins, as they’re called, help the dawn cells to first signal to each other and then signal to the dusk cells. Then as the sun sets, proteins help the dusk cells signal to each other and then signal back to the dawn cells. Each signal tells the cells to synchronize with each other. Together, these two distinct signals drive the daily sleep and wake cycle. “This really shifts our view of these cells as super strong, independent oscillators to much more of a collective group working together to keep time,” said Justin Blau, a neurobiologist at New York University and co-author of the study. © 2014 The New York Times Company

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 20172 - Posted: 10.07.2014

Carl Zimmer As much as we may try to deny it, Earth’s cycle of day and night rules our lives. When the sun sets, the encroaching darkness sets off a chain of molecular events spreading from our eyes to our pineal gland, which oozes a hormone called melatonin into the brain. When the melatonin latches onto neurons, it alters their electrical rhythm, nudging the brain into the realm of sleep. At dawn, sunlight snuffs out the melatonin, forcing the brain back to its wakeful pattern again. We fight these cycles each time we stay up late reading our smartphones, suppressing our nightly dose of melatonin and waking up grumpy the next day. We fly across continents as if we could instantly reset our inner clocks. But our melatonin-driven sleep cycle lags behind, leaving us drowsy in the middle of the day. Scientists have long wondered how this powerful cycle got its start. A new study on melatonin hints that it evolved some 700 million years ago. The authors of the study propose that our nightly slumbers evolved from the rise and fall of our tiny oceangoing ancestors, as they swam up to the surface of the sea at twilight and then sank in a sleepy fall through the night. To explore the evolution of sleep, scientists at the European Molecular Biology Laboratory in Germany study the activity of genes involved in making melatonin and other sleep-related molecules. Over the past few years, they’ve compared the activity of these genes in vertebrates like us with their activity in a distantly related invertebrate — a marine worm called Platynereis dumerilii. The scientists studied the worms at an early stage, when they were ball-shaped 2-day-old larvae. The ocean swarms with juvenile animals like these. Many of them spend their nights near the ocean surface, feeding on algae and other bits of food. Then they spend the day at lower depths, where they can hide from predators and the sun’s ultraviolet rays. © 2014 The New York Times Company

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 20154 - Posted: 10.02.2014

Christie Nicholson reports. Shakespeare called sleep the chief nourisher in life’s feast. But today we know it’s so much more. Insufficient sleep contributes to the risk of cardiovascular disease, diabetes and obesity. And now a study finds that too little or too much sleep are both associated with a significant increase in sick days away from work. Almost 4,000 men and women between 30 and 64 years old (in Finland) participated in the study, which followed them for seven years. The research revealed that the absence from work due to illness increased dramatically for those who said they slept less than 6 hours or more than 9 hours per night. The sleep time that was associated with the lowest number of sick days was 7 hours 38 minutes for women and 7 hours 46 minutes for men. The study is in the journal Sleep. [Tea Lallukka, Sleep and Sickness Absence: A Nationally Representative Register-Based Follow-Up Study] Of course these findings are associative and not necessarily causal. Other factors may be responsible for the under- or oversleeping to begin with. But sleep patterns are still a warning sign for increased illness and health complications. Shakespeare put it best: Sleep…that knits up the ravell’d sleave of care. © 2014 Scientific American

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 20133 - Posted: 09.30.2014

By Tara Parker-Pope The most reliable workers are those who get seven to eight hours of sleep each night, a new study shows. Researchers from Finland analyzed the sleep habits and missed work days among 3,760 men and women over about seven years. The workers ranged in age from 30 to 64 at the start of the study. The researchers found that the use of sick days was associated with the worker’s sleep habits. Not surprisingly, they found that people who did not get enough sleep because of insomnia or other sleep problems were more likely to miss work. But notably, getting a lot of extra sleep was also associated with missed work. The workers who were most likely to take extra sick days were those who slept five hours or less or 10 hours or more. Short sleepers and long sleepers missed about five to nine more days of work than so-called optimal sleepers, workers who managed seven to eight hours of sleep each night. The workers who used the fewest number of sick days were women who slept an average of 7 hours 38 minutes a night and men who slept an average of 7:46. The study results were published in the September issue of the medical journal Sleep. © 2014 The New York Times Company

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 20074 - Posted: 09.15.2014

by Simon Makin Talking in your sleep might be annoying, but listening may yet prove useful. Researchers have shown that sleeping brains not only recognise words, but can also categorise them and respond in a previously defined way. This could one day help us learn more efficiently. Sleep appears to render most of us dead to the world, our senses temporarily suspended, but sleep researchers know this is a misleading impression. For instance, a study published in 2012 showed that sleeping people can learn to associate specific sounds and smells. Other work has demonstrated that presenting sounds or smells during sleep boosts performance on memory tasks – providing the sensory cues were also present during the initial learning. Now it seems the capabilities of sleeping brains stretch even further. A team led by Sid Kouider from the Ecole Normale Supérieur in Paris trained 18 volunteers to classify spoken words as either animal or object by pressing buttons with their right or left hand. Brain activity was recorded using EEG, allowing the researchers to measure the telltale spikes in activity that indicate the volunteers were preparing to move one of their hands. Since each hand is controlled by the motor cortex on the opposite side of the brain, these brainwaves can be matched to the intended hand just by looking at which side of the motor cortex is active. © Copyright Reed Business Information Ltd.

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 17: Learning and Memory
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep; Chapter 13: Memory, Learning, and Development
Link ID: 20066 - Posted: 09.12.2014

Ever wonder why it’s hard to focus after a bad night’s sleep? Using mice and flashes of light, scientists show that just a few nerve cells in the brain may control the switch between internal thoughts and external distractions. The study, partly funded by the National Institutes of Health, may be a breakthrough in understanding how a critical part of the brain, called the thalamic reticular nucleus (TRN), influences consciousness. “Now we may have a handle on how this tiny part of the brain exerts tremendous control over our thoughts and perceptions,” said Michael Halassa, M.D., Ph.D., assistant professor at New York University’s Langone Medical Center and a lead investigator of the study. “These results may be a gateway into understanding the circuitry that underlies neuropsychiatric disorders.” The TRN is a thin layer of nerve cells on the surface of the thalamus, a center located deep inside the brain that relays information from the body to the cerebral cortex. The cortex is the outer, multi-folded layer of the brain that controls numerous functions, including one’s thoughts, movements, language, emotions, memories, and visual perceptions. TRN cells are thought to act as switchboard operators that control the flow of information relayed from the thalamus to the cortex. To understand how the switches may work, Dr. Halassa and his colleagues studied the firing patterns of TRN cells in mice during sleep and arousal, two states with very different information processing needs. The results published in Cell, suggest that the TRN has many switchboard operators, each dedicated to controlling specific lines of communication. Using this information, the researchers could alter the attention span of mice.

Related chapters from BP7e: Chapter 18: Attention and Higher Cognition; Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 14: Attention and Consciousness; Chapter 10: Biological Rhythms and Sleep
Link ID: 19965 - Posted: 08.16.2014