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If you’ve ever been put under anaesthesia, you might recall the disorienting feeling of blinking your eyes one moment and the next, waking up hours later. Now, findings from a new study illustrate just how profoundly general anaesthesia alters the state of the brain as it induces and maintains unconsciousness. It’s the first paper to track travelling brain waves in subjects all the way through the process of losing to regaining consciousness. An interdisciplinary team has found that the commonly used anaesthetic, propofol, substantially alters how different frequencies of brain waves travel along the cortex – the surface of the brain – and the research has been published in the Journal of Cognitive Neuroscience. Unconsciousness induced by propofol may be in part due to an increase in the strength and direction of slow delta traveling brain waves that disrupt higher-frequency waves associated with cognition. “The rhythms that we associate with higher cognition are drastically altered by propofol,” explains senior author Earl Miller, professor of neuroscience with the Department of Brain and Cognitive Sciences at the Massachusetts Institute of Technology (MIT) in the US. “The beta traveling waves seen during wakefulness are pushed aside, redirected by delta traveling waves that have been altered and made more powerful by the anaesthetic,” he says. “The deltas come through like a bull in a china shop.” Conscious brains show a mixture of brain waves of different frequencies, which rotate or travel straight in various directions: you could think of them like the numerous waves on a choppy ocean.

Related chapters from BN: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 28314 - Posted: 05.04.2022

By Elizabeth Preston On dry nights, the San hunter-gatherers of Namibia often sleep under the stars. They have no electric lights or new Netflix releases keeping them awake. Yet when they rise in the morning, they haven’t gotten any more hours of sleep than a typical Western city-dweller who stayed up doom-scrolling on their smartphone. Research has shown that people in non-industrial societies — the closest thing to the kind of setting our species evolved in — average less than seven hours a night, says evolutionary anthropologist David Samson at the University of Toronto Mississauga. That’s a surprising number when you consider our closest animal relatives. Humans sleep less than any ape, monkey or lemur that scientists have studied. Chimps sleep around 9.5 hours out of every 24. Cotton-top tamarins sleep around 13. Three-striped night monkeys are technically nocturnal, though really, they’re hardly ever awake — they sleep for 17 hours a day. Samson calls this discrepancy the human sleep paradox. “How is this possible, that we’re sleeping the least out of any primate?” he says. Sleep is known to be important for our memory, immune function and other aspects of health. A predictive model of primate sleep based on factors such as body mass, brain size and diet concluded that humans ought to sleep about 9.5 hours out of every 24, not seven. “Something weird is going on,” Samson says. Research by Samson and others in primates and non-industrial human populations has revealed the various ways that human sleep is unusual. We spend fewer hours asleep than our nearest relatives, and more of our night in the phase of sleep known as rapid eye movement, or REM. The reasons for our strange sleep habits are still up for debate but can likely be found in the story of how we became human. Graph shows average time spent sleep of different primate species. Humans sleep the least at seven hours per night; the three-striped night monkey sleeps the most at nearly 17 hours. © 2022 Annual Reviews

Related chapters from BN: 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: 28310 - Posted: 04.30.2022

By Michele Lent Hirsch Sleep problems are a hallmark of modern American life — perhaps never more so than recently. In 2016, the Centers for Disease Control and Prevention found that a third of Americans were getting too little sleep at night. But then came the stressors of the pandemic, job losses, disrupted schedules and closed schools, which kept record numbers of Americans up at night or unable to wake up in the morning. As many as 2 in 3 Americans reported getting either too much or too little sleep, in a survey from the American Psychological Association during the pandemic’s second year. And the insomnia of the past two years may be stubbornly hanging on: Many people continue having more trouble falling asleep or staying asleep or have seen unusual shifts in their sleep schedules. All of this is taking a toll. “These different types of sleep changes seem to be closely related to [problems with] mental health,” says Karianne Dion, a graduate student in clinical psychology at the University of Ottawa. Research she co-wrote, published in the Journal of Sleep Research in 2021, found “worse symptoms of stress, anxiety, and depression” among those who are sleeping less or going to bed later and waking up later than before. Researchers have long known that anxiety and depression can lead to sleeplessness, while sleeping poorly can increase the likelihood of anxiety and depression. But a good night’s rest is also critical for a strong immune system, as well as for health overall. Insufficient sleep over time is associated with a greater risk of diabetes, high blood pressure and heart disease, according to the CDC. It can lead to memory and cognitive issues as well. So how can we get the sleep we need? Here’s how to solve seven common problems that can interfere with your rest and your health. © 1996-2022 The Washington Post

Related chapters from BN: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 28303 - Posted: 04.27.2022

Kayt Sukel Each night, as you transition into deep sleep from wakefulness, your body undergoes a remarkable transformation. Your muscles relax. Your breathing slows. Your temperature and blood pressure drop. Even your brain activity changes, decelerating into slow, coordinated waves. Despite these remarkable physiological changes, scientists are now learning that the brain is far from idle during sleep. Rather, it remains hard at work, facilitating memory and learning while uncoupled from the external world. “For a long time, we believed that being awake all day depleted you and that sleep was what was required to restore and reinvigorate the whole body, including the brain,” says Robert Stickgold, a pioneering sleep researcher at Harvard Medical School. “It turns out that rest has very little to do with the function of sleep—rather, our brain is sorting and consolidating the information we learned during the day so we can better access it when it’s needed.” Anyone who has ever pulled an all-nighter knows the effect that sleep deprivation can have on cognitive function, including one’s ability to learn and retain new information. Yet, over the last few decades, neuroscientists across the globe have learned that sleep plays an integral role in memory—and it is a role that is highly conserved across the animal kingdom. To better understand how sleep helps us remember, these researchers have been working to characterize not only the physiological changes observed during sleep, but also the neural mechanisms underlying them. Nearly every animal on earth, from fruit flies to non-human primates, experiences some form of sleep, a naturally recurring state of altered consciousness and inhibited sensory activity. And while the exact amount of time spent in slumber, and the patterns of neural activity, differ from animal to animal, humans are no different. We need sleep to thrive. © 2022 The Dana Foundation.

Related chapters from BN: 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 and Learning
Link ID: 28285 - Posted: 04.16.2022

By Erin Blakemore From the streetlights outside our bedrooms to the lamps and devices inside, sleeping with some amount of light has become a way of life for many. That may not be such a bright idea. Research suggests that sleeping in a moderately lit room could affect metabolic and cardiovascular health compared with snoozing in a room with dimmer light. We don’t need more sleep. We just need more darkness. In a study published in PNAS, researchers at Northwestern University had two groups of 10 young adults sleep in differently lit rooms. One group slept in rooms with dim light for two nights; the other slept one night in a room with dim night and the next in a room with moderate overhead light — about the equivalent of an overcast day. Participants wore heart monitors at night. In the morning, they did a variety of glucose tests. Both groups got the same amount of sleep but their bodies experienced very different nights. Both groups responded well to insulin the first night, when they both slept in dim lighting. On the second night, however, the group sleeping in brighter lighting didn’t respond as well to insulin. The dim light sleepers’ insulin resistance scores fell about 4 percent on the second night, while the bright sleepers’ rose about 15 percent. Their heart rates were faster on the bright night, too. The heightened heart rate and other measures led the researchers to conclude that light activates the sympathetic nervous system, which usually dominates bodily functions during the day.

Related chapters from BN: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 28252 - Posted: 03.26.2022

By Veronique Greenwood Sharks are celebrated for their apparently ceaseless motion — a small handful of species such as great white sharks must even swim to breathe, keeping water washing over their gills. Still, all that moving doesn’t preclude sharks from having a rest. Sleep across the animal kingdom manifests itself in many peculiar ways, like the birds whose brains sleep one half at a time or the bats that spend almost every hour of their day snoozing. And in a paper published in Current Biology on Wednesday, researchers confirmed that the draughtsboard shark, a small nocturnal shark native to New Zealand, appears to be sleeping during periods of calm, reporting that their metabolism and posture change significantly during these bouts of repose. They do, however, in a creepy touch, keep their eyes open for a lot of it. Further research will be required to demonstrate that other kinds of sharks catch underwater z’s like the draughtsboard shark. But the new study supports the hypothesis that one reason organisms might have evolved sleep is as a tool for conserving energy. Draughtsboard sharks were identified last year as sleepers by this same group of researchers based in New Zealand and Australia. They watched captured sharks carefully in tanks and tested their responses to disturbances during their restful periods. (These sharks are not among those that swim to breathe; they hang out on the ocean floor and pump water over their gills.) The team found that it was more difficult to prompt the sharks into movement if they had been still for a long time, suggesting they were in fact sleeping. This time, said Craig Radford, a professor of marine science at the University of Auckland and an author of the new paper, the researchers were looking to compare the sharks’ metabolisms during these periods of calm, defined as being still for longer than five minutes, with when they were resting for shorter periods and when they were actively swimming. They used a specially built tank with instruments that let them monitor how much oxygen the sharks were using, a way to indirectly measure metabolism. Seven sharks each spent 24 hours in the tank, and the researchers found that these states were indeed quite different. © 2022 The New York Times Company

Related chapters from BN: 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: 28234 - Posted: 03.11.2022

ByKelly Servick In 1997, Laura Gould put her 15-month-old daughter, Maria, down for a nap and returned to find her unresponsive. She had died suddenly, with no clues to explain the tragedy besides a fever the night before. When her daughter’s body was sent to the medical examiner’s office, “I thought they’d call me in an hour and tell me what happened … like on TV,” Gould says. Months later, neither that office nor independent pathologists had an explanation. “I hated ending it with ‘the autopsy was inconclusive, go on and live your life now,’” she says. “It just didn’t really feel like that was an option.” Gould co-founded a nonprofit foundation to support grieving parents, raise research funds, and increase awareness of sudden unexplained death in childhood (SUDC), a term used for children older than 12 months. In the United States, roughly 400 deaths fall into this category each year—about one-quarter as many as are labeled sudden infant death syndrome (SIDS). Two recent genetic analyses, one funded in part by Gould’s SUDC Foundation, now suggest potential causes for at least a small fraction of cases: mutations in genes associated with epilepsy, heart arrhythmias, and neurodevelopmental disorders. “Having this data is important,” says Marco Hefti, a neuropathologist at the University of Iowa Carver College of Medicine who was not involved in the new studies. SUDC is not a single disease, but “a grab bag of different things—and the more of those different things you can pull out, the better for everybody.” Neither study can say with certainty that a mutation is responsible for a child’s death. But the findings provide a basis for animal studies that could reveal how the genetic changes interfere with vital functions. They might also inform future child death investigations and potentially even screening programs to prevent deaths. Research on SUDC has lagged that on the more common and better known SIDS. Yet, biologically, SIDS and SUDC “may be part of a spectrum,” says Ingrid Holm, a medical geneticist at Boston Children’s Hospital. In both, death often occurs during sleep, and researchers suspect contributors including undetected heart defects, metabolic disorders, and central nervous system abnormalities. The children who die are roughly 10 times more likely than the average child to have a history of febrile seizures—convulsions that come with fevers in young children, notes neurologist Orrin Devinsky of New York University (NYU) Langone Health. © 2022 American Association for the Advancement of Science.

Related chapters from BN: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 28200 - Posted: 02.12.2022

Ian Sample Science editor Getting an hour or so more sleep each night can help people to cut calories, according a small clinical trial in overweight adults. Researchers in the US found that people who typically slept for less than 6.5 hours a night shed an average of 270 calories from their daily intake when they got an extra 1.2 hours of sleep. Sustained over three years, the reduction in calories could lead people to lose about 12kg (26lbs) without changing their diet during the day, the scientists believe. Some participants in the study consumed 500 fewer calories a day after improving their sleep. The study was not designed to look at weight loss, but researchers noticed the fall in calories within two weeks of patients changing their sleep patterns. “If healthy sleep habits are maintained over longer duration, this would lead to clinically important weight loss over time,” said Dr Esra Tasali, of the University of Chicago’s sleep centre. “Many people are working hard to find ways to decrease their caloric intake to lose weight – well, just by sleeping more, you may be able to reduce it substantially.” The trial studied 80 adults aged 21 to 40 with a body mass index between 25 and 29.9, meaning they were overweight. Half of the participants were randomly assigned to receive personalised sleep hygiene counselling aimed at extending the amount of time they slept each night. © 2022 Guardian News & Media Limited

Related chapters from BN: 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: 28191 - Posted: 02.09.2022

By Amelia Nierenberg A couple of glasses of wine or a few drinks in the evening will probably make you fall asleep faster than normal. Who among us hasn’t left the dishes for the next morning or neglected a skin-care routine after a dinner party or festive night out? But even if you thud into dreamland, there’s a good chance that too much alcohol will mean a fitful night of sleep. That’s because alcohol disrupts what’s known as your sleep architecture, the normal phases of deeper and lighter sleep we go through every night. A night of drinking can “fragment,” or interrupt, these patterns, experts say, and you may wake up several times as you ricochet through the usual stages of sleep. “You pay for it in the second half of the night,” said Dr. Jennifer Martin, a psychologist and professor of medicine at the University of California, Los Angeles. Alcohol is “initially sedating, but as it’s metabolized, it’s very activating.” Here’s how it breaks down. In the first half of the night, when fairly high levels of alcohol are still coursing through your bloodstream, you’ll probably sleep deeply and dreamlessly. One reason: In the brain, alcohol acts on gamma-aminobutyric acid, or GABA, a neurotransmitter that inhibits impulses between nerve cells and has a calming effect. Alcohol can also suppress rapid eye movement, or REM sleep, which is when most dreaming occurs. Later in the night, as alcohol levels drop, your brain kicks into overdrive. You may toss and turn as your body undergoes a rebound arousal. “As the levels decline, you’re going to get more issues with the fragmentation,” said Dr. R. Nisha Aurora, a member of the board of directors of the American Academy of Sleep Medicine. You’ll also probably have more vivid or stressful dreams and — because fitful sleep means that you’re waking up more regularly — you are more likely to remember them.

Related chapters from BN: Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology; Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 4: Development of the Brain; Chapter 10: Biological Rhythms and Sleep
Link ID: 28183 - Posted: 02.02.2022

By Linda Searing Among people who have covid-19, those who have certain sleep disorders (including sleep apnea) face a 31 percent greater chance of developing a severe case that requires hospitalization, or dying from the disease, than do people who have covid-19 and who do not have sleep-disturbed breathing, according to research published in The study links the increase in risk to breathing disorders that can cause oxygen levels to drop during sleep, creating a low oxygen level called hypoxia. The researchers found that having such a sleep-related breathing disorder did not make people more likely to contract the coronavirus. They wrote, however, that having low oxygen levels “may play a role in worse outcomes once the viral illness evolves,” describing hypoxia as an “amplifier” of covid effects. The findings were based on data from 5,402 adults (average age 56) who had undergone sleep studies and coronavirus testing in 2020 through the Cleveland Clinic Health System. For someone with sleep apnea, which is one of the most common sleep disorders, breathing repeatedly stops and starts during sleep, sometimes 30 times or more an hour and often is accompanied by gasping or snorting sounds. This causes hypoxia. Treatment often involves using what is called positive airway pressure (PAP) while sleeping. The person wears a mask, which has a tube connected to a small PAP machine that sits bedside. It pumps pressurized air into the upper airway, keeping it open and allowing normal breathing. The researchers suggested further studies to determine whether such treatment would improve covid-19 outcomes for people with a sleep disorder. © 1996-2021 The Washington Post

Related chapters from BN: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 28126 - Posted: 12.29.2021

By Richard Sandomir Allan Rechtschaffen, an indefatigable sleep researcher at the University of Chicago who tested the effects of sleep deprivation, studied dreaming, narcolepsy, napping and insomnia and standardized the measurement of sleep stages, died on Nov. 29 at his home in Chicago. He was 93. His wife, Karen Rechtschaffen, confirmed the death. The University of Chicago was an established center of sleep research when Professor Rechtschaffen arrived on its campus in 1957 as a psychology instructor. Four years earlier, Nathaniel Kleitman, a physiologist, and Eugene Aserinsky, a graduate student, had written a paper that reported the discovery of rapid eye movement, or REM, during sleep, an indication of dreaming. The finding appealed to Professor Rechtschaffen’s fascination with the mind’s effect on the body. “This was a perfect vehicle for studying that issue,” he said in an interview in 2010 with the Sleep Research Society, which he helped start 50 years earlier. “You could conceive of it as the mind turning on with the REM period and turning off with the end of the REM period. So you could see periods of mind and periods of no mind.” REM and other aspects of sleep became the focus of his career. In 1958, he was named director of the university’s sleep research laboratory, where his experiments on animals and humans over the next 41 years helped him define a challenge that he described this way: “If sleep doesn’t serve an absolutely vital function, it is the biggest mistake evolution ever made.” His best-known experiment concerned self-deprivation using rats. As Professor Rechtschaffen and his colleagues reported in the journal Science in 1983, they had placed two rats at a time in a plexiglass box, each with an electrode attached from its head to a computer and each placed on one-half of a divided disk built over shallow water. When the experimental rat tried to sleep, the disk automatically rotated, forcing the animal to stay awake. The control rat was treated similarly but could sleep when the other rat was awake and the disk was not moving. © 2021 The New York Times Company

Related chapters from BN: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 28116 - Posted: 12.18.2021

Sofia Moutinho When Thomas Edison hit a wall with his inventions, he would nap in an armchair while holding a steel ball. As he started to fall asleep and his muscles relaxed, the ball would strike the floor, waking him with insights into his problems. Or so the story goes. Now, more than 100 years later, scientists have repeated the trick in a lab, revealing that the famous inventor was on to something. People following his recipe tripled their chances of solving a math problem. The trick was to wake up in the transition between sleep and wakefulness, just before deep sleep. “It is a wonderful study,” says Ken Paller, a cognitive neuroscientist at Northwestern University who was not part of the research. Prior work has shown that passing through deep sleep stages helps with creativity, he notes, but this is the first to explore in detail the sleep-onset period and its role in problem-solving. In this transitional period, we are not quite awake, but also not deeply asleep. It can be as short as a minute and occurs right when we start to doze off. Our muscles relax, and we have dreamlike visions or thoughts called hypnagogia, generally related to recent experiences. This phase slips by unnoticed most of the time unless it is interrupted by waking. Like Edison, surrealist painter Salvador Dalí believed interrupting sleep’s onset could boost creativity. (He used a heavy key instead of a metal ball.) To see whether Dalí and Edison were right, researchers recruited more than 100 easy sleepers. The team gave them a math test that required them to convert strings of eight digits into new strings of seven by using specific rules in a stepwise manner, such as “repeat the number if the previous and next digit are identical.” The volunteers weren’t told that there was an easier way to get the right answers by following a hidden rule: The second number in their final string was always the same as the last number in the same string. © 2021 American Association for the Advancement of Science.

Related chapters from BN: 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 and Learning
Link ID: 28106 - Posted: 12.11.2021

Sophie Fessl Catching some z’s repairs a day’s damage to neurons’ DNA, at least in zebrafish. While the fish are awake, DNA damage accumulates, which, through a buildup of the DNA repair protein Parp1, triggers sleep, according to a study published today (November 18) in Molecular Cell. The study is “pivotal in providing evidence regarding sleep and its role in DNA damage and repair,” writes anesthesiologist Siu Wai Choi of the University of Hong Kong in an email to The Scientist. Choi led an earlier study that established a link between sleep deprivation and DNA damage in doctors but was not involved in the current research. Cells routinely face stress, such as exposure to radiation, that can leave their DNA damaged. Cells therefore have an arsenal of repair proteins to mend the DNA or, if it’s irreparable, trigger cell death. Neuroscientist Lior Appelbaum and his team at Bar-Ilan University in Israel had previously found that DNA damage increases during the day and decreases during the night, suggesting that sleep could help repair this damage. In the new study, they investigated whether DNA damage is the reason why zebrafish—and, by extension, perhaps other animals—sleep. When postdoc David Zada and other authors induced DNA damage in the neurons of zebrafish larvae by inducing neuronal activity or using UV radiation, the fish slept longer. “It makes the fish tired,” says Appelbaum. © 1986–2021 The Scientist.

Related chapters from BN: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 28081 - Posted: 11.20.2021

David Robson Michelle Carr is frequently plagued by tidal waves in her dreams. What should be a terrifying nightmare, however, can quickly turn into a whimsical adventure – thanks to her ability to control her dreams. She can transform herself into a dolphin and swim into the water. Once, she transformed the wave itself, turning it into a giant snail with a huge shell. “It came right up to me – it was a really beautiful moment.” There’s a thriving online community of people who are now trying to learn how to lucid dream. (A single subreddit devoted to the phenomenon has more than 400,000 members.) Many are simply looking for entertainment. “It’s just so exciting and unbelievable to be in a lucid dream and to witness your mind creating this completely vivid simulation,” says Carr, who is a sleep researcher at the University of Rochester in New York state. Others hope that exercising skills in their dreams will increase their real-life abilities. “A lot of elite athletes use lucid dreams to practise their sport.” And there are more profound reasons to exploit this sleep state, besides personal improvement. By identifying the brain activity that gives rise to the heightened awareness and sense of agency in lucid dreams, neuroscientists and psychologists hope to answer fundamental questions about the nature of human consciousness, including our apparently unique capacity for self-awareness. “More and more researchers, from many different fields, have started to incorporate lucid dreams in their research,” says Carr. This interest in lucid dreaming has been growing in fits and starts for more than a century. Despite his fascination with the interaction between the conscious and subconscious minds, Sigmund Freud barely mentioned lucid dreams in his writings. Instead, it was an English aristocrat and writer, Mary Arnold-Forster, who provided one of the earliest and most detailed descriptions in the English language in her book Studies in Dreams. © 2021 Guardian News & Media Limited

Related chapters from BN: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 18: Attention and Higher Cognition
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep; Chapter 14: Attention and Higher Cognition
Link ID: 28079 - Posted: 11.17.2021

By Elizabeth Pennisi Dive among the kelp forests of the Southern California coast and you may spot orange puffball sponges (Tethya californiana)—creatures that look like the miniature pumpkins used for pies. No researchers paid them much mind until 2017, when William Joiner, a neuroscientist at the University of California (UC), San Diego, decided to look into whether sponges take naps. That’s not as silly a question as it seems. Over the past few years, studies in worms, jellyfish, and hydra have challenged the long-standing idea that sleep is unique to creatures with brains. Now, “The real frontier is finding an animal that sleeps that doesn’t have neurons at all,” says David Raizen, a neurologist at the University of Pennsylvania (UPenn) Perelman School of Medicine. Sponges, some of the earliest animals to appear on Earth, fit that description. To catch one snoozing could upend researchers’ definition of sleep and their understanding of its purpose. Scientists have often defined sleep as temporary loss of consciousness, orchestrated by the brain and for the brain’s benefit. That makes studying sleep in brainless creatures controversial. “I do not believe that many of these organisms sleep—at least not the way you and I do,” says John Hogenesch, a genome biologist at Cincinnati Children’s Hospital Medical Center. Calling the restful, unresponsive state seen in jellyfish and hydra “sleeplike” is more acceptable to him. But others in the field are pushing for a much more inclusive view: that sleep evolved not with modern vertebrates as previously assumed, but perhaps a half-billion years ago when the first animals appeared. “I think if it’s alive, it sleeps,” says Paul Shaw, a neuroscientist from Washington University in St. Louis. The earliest life forms were unresponsive until they evolved ways to react to their environment, he suggests, and sleep is a return to the default state. “I think we didn’t evolve sleep, we evolved wakefulness.” © 2021 American Association for the Advancement of Science.

Related chapters from BN: 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: 28061 - Posted: 11.03.2021

By Brooke Jarvis Deirdre Barrett’s body was in bed, but her mind was in a library. The library was inside a very old house, with glowing oil lamps and shelves of beautiful leatherbound books. At first it felt snug and secure and timeless, exactly the sort of place an academic like Barrett, who teaches in the psychiatry department at Harvard Medical School and edits the scientific journal Dreaming, might find inviting. But as the dream went on, she remembered later, “I became less able to focus on the library and more overwhelmed by the unseen horror outside.” Beyond the windows of the softly lit library, “a terrible plague was ravaging the world.” When Barrett woke up, it was mid-March of 2020. She had been reading about the novel coronavirus in Wuhan since it began to make headlines, and she wondered, as she often did when she read about events in the news, how this one might be showing up in the dreams of the people who were experiencing it: residents on lockdown in China, overwhelmed doctors and nurses in Italy. The dreamlife of collective catastrophe was something she had studied repeatedly during her academic career — analyzing, for example, the dreams of Kuwaitis after the Iraqi invasion and those of British officers held prisoner by the Nazis during World War II, to see how the dreams compared with one another and with dreams from calmer times. As a child, Barrett was fascinated by her own dreams, which were often vivid. They tended to stay with her well after she woke up, making nights feel like a time for slipping in and out of new worlds and adventures, often ones she’d read about but was now able to interact with and inhabit fully. When she grew up, she decided, she would become a writer of fiction; many of the early stories she wrote were set not just in worlds that she imagined, but also in and out of the various dream worlds of her characters. She was deeply curious about the dream lives of other people: When she started writing for her high school newspaper, she occasionally asked her sources if they’d had dreams related to whatever she was interviewing them about. Dreams were a window, albeit a very strange one, into the way that other people and their minds worked. In college Barrett decided that fiction was not her future (though she did develop a practice of making visual art about what she saw and felt while sleeping). What she wanted was to be a scientist who studied what happened inside dreams. © 2021 The New York Times Company

Related chapters from BN: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 28060 - Posted: 11.03.2021

A new study re-emphasises the fact that oversleeping can be harmful for us – and especially for older people Says who? Says Brendan P Lucey, MD. Who? Associate professor of neurology and director of the Washington University Sleep Medicine Center. And lead author of a new study at Washington University School of Medicine (which is neither in Washington DC nor Washington state but St Louis, Missouri, confusingly). Here we go, a new study: what does it say? That it is, in fact, possible to have too much of a good thing. And if that good thing is sleep, how much is too much? Possibly anything over seven and a half hours a night. What?! What about my beauty sleep? Eight hours, absolute minimum. The study monitored 100 older adults, in their mid to late 70s. I am awake now, so tell me what they found. That there’s an association between less than five and a half hours’ sleep and, more surprisingly, more than seven and a half hours’ sleep and reduced cognitive performance for older adults. So how much is right for the over-75s? The “sweet spot” is somewhere in the middle range, between five and a half and seven and a half hours’ kip. What else is associated with cognitive decline in older people? Alzheimer’s is the main cause, contributing to around 70% of dementia cases. “It’s been challenging to determine how sleep and different stages of Alzheimer’s disease are related,” said Lucey. “But that’s what you need to know to start designing interventions.” © 2021 Guardian News & Media Limited

Related chapters from BN: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 28056 - Posted: 10.30.2021

Infants who sleep longer through the night and with fewer interruptions may be less likely to become overweight during their first six months of life, according to a study published in the journal SLEEP(link is external). While the research only showed a link – not a cause-effect relationship – between infants’ sleep and weight, the findings suggest that newborns can reap some of the same health benefits that others get from consistent, quality shut-eye. The research emerged from the Rise and SHINE (Sleep Health in Infancy & Early Childhood) study, which analyzes ways sleep may influence a newborn’s growth and development. The five-year study is being supported in part by the National Heart, Lung, and Blood Institute (NHLBI), part of the National Institutes of Health. “What is particularly interesting about this research is that the sleep-obesity association we see across the lifespan appears in infancy and may be predictive of future health outcomes,” said Marishka K. Brown, Ph.D., director of the National Center on Sleep Disorders Research, located within the NHLBI. Brown noted that multiple studies have shown links between good sleep and improved health. For children, this includes a reduced risk of developing obesity and diabetes, while supporting development, learning, and behavior. In the current study, researchers observed 298 newborns and found that for every hourly increase in nighttime sleep, measured between 7 p.m. and 8 a.m., the infants were 26% less likely to become overweight. Likewise, for each reduction in nighttime awakening, they were 16% less likely to become overweight.

Related chapters from BN: 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: 28047 - Posted: 10.23.2021

By Leigh Weingus I’ve struggled with sleep since I was a teenager, and have spent almost as long trying to fix it. I’ve absorbed countless books and articles on getting better sleep that instructed me to go blue-light free at least two hours before bedtime, take nightly baths to lower my body temperature, keep my phone far from my bedroom and avoid caffeine after 12 p.m. In between all my diligent sleep hygiene work, I couldn’t help but feel like there was a larger force at play. My sleep seemed to change throughout my menstrual cycle, for example, getting worse in the days before my period and significantly better afterward. When I was pregnant, I experienced the best sleep of my life, and when I stopped breastfeeding, I didn’t sleep for days. I finally started to ask myself: When we talk about getting better sleep, why aren’t we talking more about hormones? According to the National Sleep Foundation, the lifetime risk of insomnia is 40 percent higher for women than it is for men. Blaming this discrepancy entirely on hormones oversimplifies it — women also tend to take on the bulk of household worrying and emotional labor, and they tend to experience higher levels of anxiety. But according to Mary Jane Minkin, an obstetrician-gynecologist and clinical professor in the Department of Obstetrics, Gynecology, and Reproductive Sciences at the Yale School of Medicine, anecdotal evidence and studies suggest that hormones likely play a role.

Related chapters from BN: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep; Chapter 8: Hormones and Sex
Link ID: 28000 - Posted: 09.22.2021

By Sarah Lyall In the winter of 1995, the Brazilian neuroscientist Sidarta Ribeiro moved to New York to pursue his Ph.D. at Rockefeller University. His arrival, he writes in his fascinating, discursive new book, “The Oracle of Night,” precipitated one of the strangest periods of his life. Overcome by a sudden, inexplicable lassitude, Ribeiro did little but attend classes, read and sleep. But his sleep was exciting and revelatory, full of vivid, evocative dreams that enriched his waking hours. “I began to dream in English,” he writes, “and my dreams became even more intense, with representations of epic narratives through unnaturally deserted New York streets on the sunny, icy morning of an endless Sunday.” This period lasted for several months and then abruptly ended. When Ribeiro re-entered the world, as if emerging from hibernation, he was refreshed and alert, energized by a “cognitive transformation” that he felt had been enhanced by his dreaming imagination. He became fascinated by dreams — why do we have them, what do they say about us, what role do they play in our lives? — and embarked on a lifetime of study of this most interesting of topics. (He wears many hats. He got his Ph.D. in animal behavior; he is the founder and vice director of the Brain Institute at the Federal University of Rio Grande do Norte in Brazil.) “The Oracle of Night” makes a resounding case for the mystery, beauty and cognitive importance of dreams. Ribeiro marshals prodigious evidence to bolster his case that a dream is not simply “fragments of memory assembled at random” (as he summarizes Francis Crick’s dismissive position), but instead is a “privileged moment for prospecting the unconscious” — a phenomenon that, in Carl Jung’s words, “prepares the dreamer for the events of the following day.” © 2021 The New York Times Company

Related chapters from BN: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 27979 - Posted: 09.08.2021