Links for Keyword: Sleep

Follow us on Facebook and Twitter, or subscribe to our mailing list, to receive news updates. Learn more.


Links 1 - 20 of 849

By Diana Kwon Across the animal kingdom, nearly all creatures sleep or display sleep-like states. The roundworm, Caenorhabditis elegans, does not sleep in a typical day-night cycle like humans and many other animals. Instead, these worms catch most of their z’s while transitioning from one larval stage to another, during a period called lethargus. When these creatures fall asleep, most of their neurons become inactive spontaneously, suggesting that sleep—at least in worms—is a passive state of the brain, according to a study published today (June 22) in Science. “The condition between sleep to wakefulness is probably one of the most drastic changes that our brains undergo,” says Manuel Zimmer, a neuroscientist at the Research Institute of Molecular Pathology at the Vienna Biocenter in Austria. “How a brain can switch between such drastically different states is not really understood.” To investigate this process, Zimmer and colleagues examined the brains of C. elegans. These worms do indeed have primitive brains, yet their nervous system comprises only 302 neurons, making it much easier to tackle than, say, the human brain, with billions of neurons, or even the fly brain, which has around 100,000 nerve cells. Using transgenic worms engineered with a fluorescent indicator that becomes active in response to high calcium levels in neurons (a proxy for neural activity), the researchers imaged the C. elegans brain during the transitions between sleep and wake states by adjusting oxygen levels. Because these soil-dwelling creatures live among low levels of oxygen (10 percent), atmospheric oxygen concentrations (21 percent) induce hyperactivity and wakefulness. © 1986-2017 The Scientist

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 23775 - Posted: 06.26.2017

by Laura Sanders When we brought our first baby home from the hospital, our pediatrician advised us to have her sleep in our room. We put our tiny new roommate in a crib near our bed (though other containers that were flat, firm and free of blankets, pillows or stuffed animals would have worked, too). The advice aims to reduce the risk of sleep-related deaths, including sudden infant death syndrome, or SIDS. Studies suggest that in their first year of life, babies who bunk with their parents (but not in the same bed) are less likely to die from SIDS than babies who sleep in their own room. The reasons aren’t clear, but scientists suspect it has to do with lighter sleep: Babies who sleep near parents might more readily wake themselves up and avoid the deep sleep that’s a risk factor for SIDS. That’s an important reason to keep babies close. Room sharing also makes sense from a logistical standpoint. Middle of the night feedings and diaper changes are easier when there’s less distance between you and the babe. But babies get older. They start snoring a little louder and eating less frequently, and it’s quite natural to wonder how long this room sharing should last. That’s a question without a great answer. In November 2016, the American Academy of Pediatrics task force on SIDS updated its sleep guidelines. The earlier recommendation was that babies ought to sleep in parents’ bedrooms for an entire year. The new suggestion softens that a bit to say infants should be there for “ideally for the first year of life, but at least for the first 6 months.” © Society for Science & the Public 2000 - 2017

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: 23766 - Posted: 06.23.2017

Jon Hamilton Thanks to Sigmund Freud, we all know what it means to dream about swords, sticks and umbrellas. Or maybe we don't. "For 100 years, we got stuck into that Freudian perspective on dreams, which turned out to be not scientifically very accurate," says Robert Stickgold, a sleep researcher and associate professor of psychiatry at Harvard Medical School. "So it's only been in the last 15 to 20 years that we've really started making progress." Today, most brain scientists reject Freud's idea that dreams are highly symbolic representations of unconscious (and usually sexual) desire. That dream umbrella, they say, is probably just an umbrella. But researchers are still trying to figure out what dreams do represent, and what their purpose is. "There's not really a solid theory about why dreaming is there," says Benjamin Baird, a postdoctoral fellow at the Center for Sleep and Consciousness at the University of Wisconsin ­– Madison. "It's a big mystery." We all have a future self, a version of us that is better, more successful. It can inspire us to achieve our dreams, or mock us for everything we have failed to become. In this episode of the NPR podcast Invisibilia, hosts Alix Spiegel and Hanna Rosin talk to a woman who believes she can connect with her younger self in dreams. © 2017 npr

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 23765 - Posted: 06.23.2017

By JUSTIN GILLIS Global warming caused by human emissions of greenhouse gases is having clear effects in the physical world: more heat waves, heavier rainstorms and higher sea levels, to cite a few. In recent years, though, social scientists have been wrestling with a murkier question: What will climate change mean for human welfare? Forecasts in this realm are tricky, necessarily based on a long chain of assumptions. Scientific papers have predicted effects as varied as a greater spread of tropical diseases, fewer deaths from cold weather and more from hot weather, and even bumpier rides on airplanes. Now comes another entry in this literature: a prediction that in a hotter world, people will get less sleep. In a paper published online Friday by the journal Science Advances, Nick Obradovich and colleagues predicted more restless nights, especially in the summer, as global temperatures rise. They found that the poor, who are less likely to have air-conditioning or be able to run it, as well as the elderly, who have more difficulty regulating their body temperature, would be hit hard. If global emissions are allowed to continue at a high level, the paper found, then additional nights of sleeplessness can be expected beyond what people normally experience. By 2050, for every 100 Americans, an extra six nights of sleeplessness can be expected every month, the researchers calculated. By 2099, that would more than double, to 14 additional nights of tossing and turning each month for every 100 people, in their estimation. Researchers have long known that being too hot or too cold at night can disturb anyone’s sleep, but nobody had thought to ask how that might affect people in a world grown hotter because of climate change. Dr. Obradovich is a political scientist who researches both the politics of climate change and its likely human impacts, holding appointments at Harvard and the Massachusetts Institute of Technology. He started the research while completing a doctoral degree at the University of California, San Diego. © 2017 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: 23666 - Posted: 05.27.2017

By Andy Coghlan Burning the midnight oil may well burn out your brain. The brain cells that destroy and digest worn-out cells and debris go into overdrive in mice that are chronically sleep-deprived. In the short term, this might be beneficial – clearing potentially harmful debris and rebuilding worn circuitry might protect healthy brain connections. But it may cause harm in the long term, and could explain why a chronic lack of sleep puts people at risk of Alzheimer’s disease and other neurological disorders, says Michele Bellesi of the Marche Polytechnic University in Italy. Bellesi reached this conclusion after studying the effects of sleep deprivation in mice. His team compared the brains of mice that had either been allowed to sleep for as long as they wanted or had been kept awake for a further eight hours. Another group of mice were kept awake for five days in a row – mimicking the effects of chronic sleep loss. The team specifically looked at glial cells, which form the brain’s housekeeping system. Earlier research had found that a gene that regulates the activity of these cells is more active after a period of sleep deprivation. One type of glial cell, called an astrocyte, prunes unnecessary synapses in the brain to remodel its wiring. Another type, called a microglial cell, prowls the brain for damaged cells and debris. © Copyright New Scientist Ltd.

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 23657 - Posted: 05.24.2017

Susan Milius A question flamingo researchers get asked all the time — why the birds stand on one leg — may need rethinking. The bigger puzzle may be why flamingos bother standing on two. Balance aids built into the birds’ basic anatomy allow for a one-legged stance that demands little muscular effort, tests find. This stance is so exquisitely stable that a bird sways less to keep itself upright when it appears to be dozing than when it’s alert with eyes open, two Atlanta neuromechanists report May 24 in Biology Letters. “Most of us aren’t aware that we’re moving around all the time,” says Lena Ting of Emory University, who measures what’s called postural sway in standing people as well as in animals. Just keeping the human body vertical demands constant sensing and muscular correction for wavering. Even standing robots “are expending quite a bit of energy,” she says. That could have been the case for flamingos, she points out, since effort isn’t always visible. Translate that improbably long flamingo leg into human terms, and the visible part of the leg would be just the shin down. A flamingo’s hip and knee lie inside the bird’s body. Ting and Young-Hui Chang of the Georgia Institute of Technology tested balance in fluffy young Chilean flamingos coaxed onto a platform attached to an instrument that measures how much they sway. Keepers at Zoo Atlanta hand-rearing the test subjects let researchers visit after feeding time in hopes of catching youngsters inclined toward a nap — on one leg on a machine. “Patience,” Ting says, was the key to any success in this experiment. |© Society for Science & the Public 2000 - 2017

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep; Chapter 5: The Sensorimotor System
Link ID: 23656 - Posted: 05.24.2017

Nicola Davis Air pollution might be linked to poor sleep, say researchers looking into the impact of toxic air on our slumbers. The study explored the proportion of time participants spent asleep in bed at night compared with being awake – a measure known as sleep efficiency. The results reveal that greater exposure to nitrogen dioxide and small particulates known as PM 2.5s are linked with a greater chance of having low sleep efficiency. That, researchers say, could be down to the impact of air pollution on the body. “Your nose, your sinuses and the back of your throat can all be irritated by those pollutants so that can cause some sleep disruption as well as from breathing issues,” said Martha Billings, assistant professor of medicine at the University of Washington and co-author of the research. Billings added that pollutants entering the blood could have an effect on the brain and hence the regulation of breathing. The study, presented at the American Thoracic Society’s annual international conference, drew on air pollution data captured for nitrogen dioxide and PM2.5 levels over a five-year period in six US cities, including data captured near the homes of the 1,863 participants. The data was then used to provide estimates of pollution levels in the home. Researchers then captured data from medical-grade wearable devices worn by the participants on their wrists over a period of seven consecutive days to monitor fine movements while they slept – an approach that offers insights into how long each participant spent asleep or awake.

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 23649 - Posted: 05.23.2017

By PERRI KLASS, M.D. Why do children wake up early when they are young but want to stay in bed till noon as teenagers? Experts say it’s biology. Adolescents’ bodies want to stay up late and sleep late, putting them out of sync with what their school schedules demand of them. So kids have trouble waking up, and they often find themselves feeling drowsy in morning algebra class. But that chronic sleepiness can affect their health and well-being, their behavior, and even their safety; it becomes genuinely dangerous when sleepy teenagers get behind the wheel. At a recent conference on adolescent sleep, health and school start times, at which I gave a brief keynote, several experts made compelling arguments supporting the idea that middle and high school start times should shift to 8:30 a.m. or later, as recommended by the American Academy of Pediatrics and the American Academy of Sleep Medicine. Brian Tefft, a senior researcher with the AAA Foundation for Traffic Safety, talked about “drowsy driving.” He cited an annual study that asks, “In the past 30 days how often have you driven when you were so tired that you had a hard time keeping your eyes open?” Over the past five years, on average, a quarter of the 16- to 18-year-old licensed drivers reported driving in that condition at least once, and 2 percent said fairly often or regularly. The argument is that teenagers who face very early school start times are at risk of regular sleep deprivation. Driving after sleeping only four to five hours a night is associated with a similar crash risk as driving with an alcohol level at the legal limit. Sleeping less than four hours puts you at the same risk as driving with double the legal alcohol limit. (This is not only true for adolescents, but for all of us.) Drowsy driving may not be the only risk that tired teenagers take. Wendy Troxel, a clinical psychologist and senior behavioral and social scientist at RAND, talked about the “adolescent health paradox,” that teenagers, who are in a developmental period of physical strength and resilience, face disproportionately high mortality rates. Unintentional injury (especially car crashes) is high on the list of causes, followed by homicide and suicide. © 2017 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: 23648 - Posted: 05.23.2017

By James Gallagher Health and science reporter, BBC News website Toddlers who spend time playing on smartphones and tablets seem to get slightly less sleep than those who do not, say researchers. The study in Scientific Reports suggests every hour spent using a touchscreen each day was linked to 15 minutes less sleep. However, those playing with touchscreens do develop their fine motor skills more quickly. Experts said the study was "timely" but parents should not lose sleep over it. There has been an explosion in touchscreens in the home, but understanding their impact on early childhood development has been lacking. The study by Birkbeck, University of London, questioned 715 parents of children under three years old. It asked how often their child played with a smartphone or tablet and about the child's sleep patterns. It showed that 75% of the toddlers used a touchscreen on a daily basis, with 51% of those between six and 11 months using one, and 92% of those between 25 and 36 months doing so as well. But children who did play with touchscreens slept less at night and more in the day. Overall they had around 15 minutes less sleep for every hour of touchscreen use. Not before bedtime? Dr Tim Smith, one of the researchers, told the BBC News website: "It isn't a massive amount when you're sleeping 10-12 hours a day in total, but every minute matters in young development because of the benefits of sleep." © 2017 BBC.

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 23491 - Posted: 04.14.2017

Nicola Davis Scientists have unpicked the regions of the brain involved in dreaming, in a study with significant implications for our understanding of the purpose of dreams and of consciousness itself. What’s more, changes in brain activity have been found to offer clues as to what the dream is about. Dreaming had long been thought to occur largely during rapid eye-movement (REM) sleep, a period of slumber involving fast brain activity similar to that when awake, but dreams have also been reported to occur during non-REM sleep, leaving scientists scratching their heads as to the hallmark of dreaming. “It seemed a mystery that you can have both dreaming and the absence of dreaming in these two different types of stages,” said Francesca Siclari, co-author of the research from the University of Wisconsin-Madison in the US. Now it seems the puzzle has been solved. In addition the team found that dreaming about faces was linked to increased high-frequency activity in the region of the brain involved in face recognition, with dreams involving spatial perception, movement and thinking similarly linked to regions of the brain that handle such tasks when awake. “[It is] a proof for the fact that dreaming really is an experience that occurs during sleep, because many researchers up until now have suggested that it is just something you invent when you wake up,” said Siclari.

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 23476 - Posted: 04.11.2017

Robin McKie Sleep is that golden chain that ties health and our bodies together. Thus wrote the English playwright Thomas Dekker in the 16th century, reflecting a view that has persisted through the centuries. Sleep is crucial to our wellbeing. Disturb it and you will find your constitution troubled and twisted out of joint. It is a view supported by science. Experiments in which men and women have endured periods of up to 11 days without shut-eye have shown that if we cannot sleep we develop increasingly severe symptoms: progressive decreases in concentration, perception and other higher mental processes. Intriguingly, these problems vanish once subjects are allowed a couple of nights curled up in their beds in a state of blissful unconsciousness. Just why we need sleep has been more difficult to answer. Freud argued that sleep allows us to have dreams in which we can act out wishes that are too disturbing to contemplate while awake. Others have maintained that sleep is a leftover from our stone age past, when it would have been dangerous to blunder around in the night at the mercy of nocturnal carnivores. So we evolved the habit of sleep to keep us safe, sound and unconscious in our caves. More recently, scientists have argued that sleep is involved in helping our bodies to recover from the vicissitudes of the day and for our brains to process the experiences of the previous 12 hours. All these theories have their proponents and opponents – for scientists are certainly far from reaching an agreement about the biological causes of sleep. However, a couple of papers published last week suggest there may be new avenues for researchers to explore so that they can learn how sleep works and why animals need it so badly.

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 23470 - Posted: 04.10.2017

By PENELOPE GREEN At M.I.T.’s Media Lab, the digital futurist playground, David Rose is investigating swaddling, bedtime stories and hammocks, as well as lavender oil and cocoons. Mr. Rose, a researcher, an inventor-entrepreneur and the author of “Enchanted Objects: Design, Human Desire and the Internet of Things,” and his colleagues have been road-testing weighted blankets to induce a swaddling sensation and listening to recordings of Icelandic fairy tales — all research into an ideal sleep environment that may culminate in a nap pod, or, as he said, “some new furniture form.” “For me, it’s a swinging bed on a screened porch in northwestern Wisconsin,” he said. “You can hear the loons and the wind through the fir trees, and there’s the weight of 10 blankets on top of me because it’s a cold night. We’re trying a bunch of interventions.” Meanwhile, at the University of California, Berkeley, Matthew P. Walker, a professor of neuroscience and psychology and the director of the Sleep and Neuroimaging Laboratory there, is working on direct current stimulation as a cure for sleeplessness in the aging brain. Dr. Walker is also sifting through the millions of hours of human sleep data he has received from Sense, a delicately lovely polycarbonate globe designed to look like the National Stadium in Beijing that measures air quality and other intangibles in your bedroom, then suggests tweaks to help you sleep better. “I’ve got a mission,” he said. “I want to reunite humanity with the sleep it is so bereft of.” Sense is the first product made by Hello Inc., a technology company started by James Proud, a British entrepreneur, for which Dr. Walker is the chief scientist. In Paris, Hugo Mercier, a computer science engineer, has invested in sound waves. He has raised over $10 million to create a headband that uses them to induce sleep. The product, called Dreem, has been beta-tested on 500 people (out of a pool of 6,500 applicants, Mr. Mercier said) and will be ready for sale this summer. © 2017 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: 23467 - Posted: 04.08.2017

By PENELOPE GREEN I’m exhausted. Aren’t you? For an article about how Silicon Valley and other innovators have taken on the challenge of sleeplessness, a $32 billion market once populated mostly by mattress and pharmaceutical companies, I tested but a few of the many hundreds of gadgets, apps, podcasts and other inventions now devoted to a good night’s sleep. As the gizmos grow more elaborate, imbued by ever more exotic technologies, they are creating a ruckus in our bedrooms, and sleep experts advocate a simpler approach. Here are a few of their tips (and a gizmo or two): ​Have someone read to you “Sleep With Me,” a wildly popular podcast by Drew Ackerman, a gravelly voiced librarian who tells excruciatingly boring bedtime stories, has millions of fans, but it makes me anxious. Mr. Rose and his colleagues stumbled upon recordings of Icelandic folk tales, which they found incomprehensible, of course, and therefore more soothing and soporific. ​Take a bath Arianna Huffington, author of “The Sleep Revolution: Transforming Your Life, One Night at a Time,” suggests following the bedtime rituals we gave our children. “You didn’t just throw your baby in bed,” she said. “There was a transition. A hot bath makes it easier for you to wash away the day.” ​Tuck in with a weighted blanket At M.I.T.’s Media Lab, the researcher David Rose and his colleagues are investigating what makes an ideal sleep environment. To evoke the feeling of many blankets on a cold night, Mr. Rose turned to the weighted blankets used as sensory therapy for autistic children. © 2017 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: 23466 - Posted: 04.08.2017

SAN FRANCISCO — The nose knows when you’re tired. Sleep deprivation seems to increase the brain’s sensitivity to food smells, researchers reported March 27 at the Cognitive Neuroscience Society’s annual meeting in San Francisco. That might make snacks more enticing — helping explain why people who burn the candle at both ends tend to eat more and gain weight. Adults operating on only four hours of sleep inhaled food odors such as those from potato chips and cinnamon rolls, and nonfood smells like fir trees while undergoing functional MRI scans. (The scientists carefully controlled participants’ food intake throughout the day.) A few weeks later, the same participants repeated the experiment — this time with a full eight hours of sleep. When tired, participants showed greater brain activity in two areas involved in olfaction — the piriform cortex and the orbitofrontal cortex — in response to food smells than they did when well rested. That spike wasn’t seen in response to nonfood odors, says study coauthor Surabhi Bhutani, of the Northwestern University Feinberg School of Medicine in Chicago. Though preliminary, the results fit with previous research showing a link between sleep deprivation and both excessive calorie consumption and weight gain (SN: 8/24/13, p. 18). |© Society for Science & the Public 2000 - 2017

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep; Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 23438 - Posted: 04.03.2017

USA Today Network Josh Hafner , For college students, new parents and employees dogged by deadlines, the all-nighter is nothing new. But going without sleep leaves you basically drunk, putting you at the equivalent of a .1% blood alcohol content as you drive to work, make decisions and interact with others. “The first thing that goes is your ability to think," said Joseph Ojile, M.D., a board member with the National Sleep Foundation. Judgement, memory and concentration all suffer impairment by the body's 17th hour without sleep, he said. “We know at 17 hours, you're at .08% blood alcohol level," he said, the legal standard for drunk driving. "At 24 hours, you’re at 0.1%." Coordination deteriorates as well in those intervening hours, said Ojile, a professor at Saint Louis University School of Medicine. Irritability sets in, too. Pain becomes more acute and the immune system suffers, he said, leaving the body more open to infection. "Here’s the worst part about the lack of judgement," Ojile said. "The person is unaware of their impairment. How scary is that? ‘I’m fine, I’ll just drive home. I’ll do my work at the nuclear plant, no problem. Or fly the plane, no problem.’" It's not entirely clear how the effects worsen past 24 hours, Ojile said, other than they do. The brain starts shutting down in trance-like microsleeps, 15- to 30-second spells that occur without the person noticing. Eventually, not sleeping results in death.

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 23404 - Posted: 03.25.2017

By Torah Kachur, A simple, non-invasive, non-medicinal, safe and cheap way to get a better night's sleep is to play some pink noise, according to a study published on Wednesday in the journal Frontiers in Human Neuroscience. Pink noise has more lower octaves than typical white noise and is hardly soothing. For example, it can be one-second pulses of the sound of a rushing waterfall. The short pieces of quick, quiet sounds would be really annoying if you were trying to fall asleep. But the pink noise isn't trying to get you to fall asleep; it's trying to keep you in a very deep sleep where you have slow brainwaves. This is one of our deepest forms of sleep and, in particular, seems to decline in aging adults. "When you play the pulses at particular times during deep sleep, it actually leads to an enhancement of the electrical signal. So it leads to essentially more of a synchronization of the neurons," said Nelly Papalambros, a PhD student at Northwestern University and the first author on the work. The pulses are timed to coincide with your entry into slow wave sleep. They sound to the same beat as your brainwaves, and they seem to increase the effectiveness of your very valuable and very elusive deep sleep. That slow wave sleep is critical for memory consolidation or, basically, your ability to incorporate new material learned that day with old material and memories. ©2017 CBC/Radio-Canada.

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: 23337 - Posted: 03.10.2017

Susan Milius Fitbit-style tracking of two wild African elephants suggests their species could break sleep records for mammals. The elephants get by just fine on about two hours of sleep a day. Much of that shut-eye comes while standing up — the animals sleep lying down only once every three or four days, new data show. Most of what scientists previously knew about sleeping elephants came from captive animals, says neuroethologist Paul Manger of the University of the Witwatersrand, Johannesburg. In zoos and enclosures, elephants have been recorded snoozing about three hours to almost seven over a 24-hour period. Monitoring African elephants in the wild, however, so far reveals more extreme behavior. Data are hard to collect, but two females wearing activity recorders for about a month averaged less sleep than other recorded mammals. Especially intriguing is the elephants’ ability to skip a night’s sleep without needing extra naps later, Manger and colleagues report March 1 in PLOS ONE. “The remarkably short amount of sleep in wild elephants is a real elephant in the room for several theories for the function of sleep,” says Niels Rattenborg of the Max Planck Institute for Ornithology in Seewiesen, Germany. Ideas that sleep restores or resets aspects of the brain for peak performance can’t explain animals that sleep only a little and don’t need catch-up rest, says Rattenborg, who wasn’t involved in the elephant study. The results also don’t fit well with the thought that animals need sleep to consolidate memories. “Elephants are usually not considered to be forgetful animals,” he says. |© Society for Science & the Public 2000 - 2017.

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: 23304 - Posted: 03.02.2017

Sleeping too much or too little can increase the likelihood of becoming obese, researchers have discovered. The study found abnormal sleeping patterns increased the risk of being overweight for those genetically predisposed to obesity. The effect was seen regardless of diet, health or socio-demographic group. The University of Glasgow study also found no clear link between sleep duration and body weight in those with a low genetic risk of obesity. Researchers looked at the effects of a short sleep of less than seven hours a night and a long sleep - more than nine hours - along with daytime napping and shift work. Negative effect They found that in people with a high genetic risk of obesity, both short-sleep and long-sleep durations further increased risk of carrying excess weight, compared with people who slept for normal durations of between seven and nine hours a night. Long sleepers with a risk of obesity were about 4kg heavier and short sleepers were about 2kg heavier than those with a similarly high genetic obesity risk with normal sleep durations. The negative affect happened irrespective of what subjects ate, their health concerns or socio-demographic factors, the research team said. The findings, based on data from almost 120,000 UK Biobank participants, showed no obvious link between sleep duration and body weight in those considered to be at a low genetic risk of obesity. Dr Jason Gill, from the Institute of Cardiovascular and Medical Sciences, said: "These data show that in people with high genetic risk for obesity, sleeping for too short or too long a time, napping during the day and shift work appears to have a fairly substantial adverse influence on body weight. © 2017 BBC.

Related chapters from BP7e: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 23303 - Posted: 03.02.2017

Ah, to sleep, perchance … to shrink your neural connections? That's the conclusion of new research that examined subtle changes in the brain during sleep. The researchers found that sleep provides a time when thebrain's synapses — the connections among neurons—shrink back by nearly 20 percent. During this time, the synapses rest and prepare for the next day, when they will grow stronger while receiving new input—that is, learning new things, the researchers said. Without this reset, known as "synaptic homeostasis," synapses could become overloaded and burned out, like an electrical outlet with too many appliances plugged in to it, the scientists said. "Sleep is the perfect time to allow the synaptic renormalization to occur … because when we are awake, we are 'slaves' of the here and now, always attending some stimuli and learning something," said study co-author Dr. Chiara Cirelli of the University of Wisconsin-Madison Center for Sleep and Consciousness. "During sleep, we are much less preoccupied by the external world … and the brain can sample [or assess] all our synapses, and renormalize them in a smart way," Cirelli told Live Science. Cirelli and her colleague, Dr. Giulio Tononi, also of the University of Wisconsin-Madison, introduced this synaptic homeostasis hypothesis (SHY) in 2003. © 2017 Scientific American

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: 23186 - Posted: 02.04.2017

Carl Zimmer Over the years, scientists have come up with a lot of ideas about why we sleep. Some have argued that it’s a way to save energy. Others have suggested that slumber provides an opportunity to clear away the brain’s cellular waste. Still others have proposed that sleep simply forces animals to lie still, letting them hide from predators. A pair of papers published on Thursday in the journal Science offer evidence for another notion: We sleep to forget some of the things we learn each day. In order to learn, we have to grow connections, or synapses, between the neurons in our brains. These connections enable neurons to send signals to one another quickly and efficiently. We store new memories in these networks. In 2003, Giulio Tononi and Chiara Cirelli, biologists at the University of Wisconsin-Madison, proposed that synapses grew so exuberantly during the day that our brain circuits got “noisy.” When we sleep, the scientists argued, our brains pare back the connections to lift the signal over the noise. In the years since, Dr. Tononi and Dr. Cirelli, along with other researchers, have found a great deal of indirect evidence to support the so-called synaptic homeostasis hypothesis. It turns out, for example, that neurons can prune their synapses — at least in a dish. In laboratory experiments on clumps of neurons, scientists can give them a drug that spurs them to grow extra synapses. Afterward, the neurons pare back some of the growth. Other evidence comes from the electric waves released by the brain. During deep sleep, the waves slow down. Dr. Tononi and Dr. Cirelli have argued that shrinking synapses produce this change. © 2017 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: 23184 - Posted: 02.03.2017