By Hallie Levine Finding that a good night’s rest has become more elusive over the years? Live well every day with tips and guidance on food, fitness and mental health, delivered to your inbox every Thursday. Older people need about the same amount of sleep as younger ones — generally, seven to eight hours, says Rosanne M. Leipzig, a professor of geriatrics and palliative medicine at the Icahn School of Medicine at Mount Sinai in New York. But about 30 percent of older people get less than seven hours of sleep daily, and almost 20 percent report either frequent insomnia or poor sleep quality, according to a 2022 study published in the journal BMC Public Health. If you have been struggling with sleep, consider the following. How your sleep cycle changes Older adults tend to have less deep (what’s called non-REM) sleep, says Ronald Chervin, chief of the Division of Sleep Medicine at University of Michigan Health in Ann Arbor. So “you may find that you’re woken more by things that would not have disturbed you before,” Leipzig says. You may also notice that you become sleepy earlier in the evening. “As we get older, our circadian rhythm — the body’s internal clock — changes,” Chervin says. This may lead you to head off to sleep earlier at night and wake up earlier in the morning. In addition, at night, older people tend to produce less antidiuretic hormone — which “instructs” the kidneys to cut back on creating fluid — than they once did, Leipzig says. As a result, you may wake up more often at night with the need to urinate. Other medical conditions, such as prostate problems or diabetes, can also contribute to those middle-of-the-night bathroom visits.

Keyword: Sleep
Link ID: 28964 - Posted: 10.17.2023

By Veronique Greenwood This morning, when the sun came up, billions of humans opened their eyes and admitted into their bodies a shaft of light from space. When the stream of photons struck the retina, neurons fired. And in every organ, in nearly every cell, elaborate machinery stirred. Each cell’s circadian clock, a complex of proteins whose levels rise and fall with the sun, clicked into gear. That clock synchronizes our bodies to the light-dark cycle of the planet by controlling the expression of more than 40% of our genome. Genes for immune signals, brain messengers and liver enzymes, to name just a few, are all transcribed to make proteins when the clock says it’s time. That means you are not, biochemically, the same person at 10 p.m. that you are at 10 a.m. It means that evenings are a more dangerous time to take large doses of the painkiller acetaminophen: Liver enzymes that protect against overdose become scarce then. It means that vaccines given in the morning and evening work differently, and that night-shift workers, who chronically disobey their clocks, have higher rates of heart disease and diabetes. People whose clocks run fast or slow are trapped in a hideous state of perpetual jet lag. “We are linked to this day in ways that I think people just push off,” the biochemist Carrie Partch tells me. If we understand the clock better, she has argued, we might be able to reset it. With that information, we might shape the treatment of diseases, from diabetes to cancer. For more than a quarter century, Partch has lived among the orchestrators of the circadian clock, the proteins whose rise and fall control its workings. As a postdoc, she produced the first visualization of the bound pair of proteins at its heart, CLOCK and BMAL1. Since then, she has continued to make visible the whorls and twists of those and other clock proteins while charting how changes to their structure add or subtract time from the day. Her achievements in pursuit of that knowledge have brought her some of the highest honors in this field of science: the Margaret Oakley Dayhoff Award from the Biophysical Society in 2018, and the National Academy of Sciences Award in Molecular Biology in 2022. Simons Foundation All Rights Reserved © 2023

Keyword: Biological Rhythms
Link ID: 28957 - Posted: 10.12.2023

By Stephanie Pappas Your bedmate is whimpering in their sleep and perhaps thrashing about. It looks like a nightmare. Should you wake them? Nope, experts say. As terrible as whatever visions that are running through their head might be, waking someone from a nightmare is more likely to ensure that they’ll remember the bad dream. And if someone appears physically distressed in their sleep like this, it’s more likely that they’re having a night terror than a nightmare; night terrors are different neurological experiences. Nightmares are a normal part of dreaming, says Deirdre Barrett, a dream researcher at Harvard Medical School and author of The Committee of Sleep (Oneiroi Press, 2001). They almost always happen in rapid eye movement (REM) sleep, the stage of sleep marked by brain activity that looks very similar to that of an awake brain. “Except for being scary, they look like every other dream,” Barrett says. During REM sleep, the brain areas responsible for long-term memory storage show altered activation, so people don’t tend to remember their nightmares unless those sleep tales are scary enough to wake them up. Once a dreamer awakens, their long-term memory regions come back on line. Most of the time, someone having a nightmare will be indistinguishable from a peaceful dreamer. During a nightmare, heart rate increases by seven beats per minute on average, says Michael Schredl, a dream and sleep researcher at the Central Institute of Mental Health in Germany. Otherwise the sleeper typically lies still in bed: during REM sleep, muscles are paralyzed, which keeps people from acting out their dreams. If someone is moving around, talking in their sleep or sleepwalking while appearing distressed, it’s more likely a night terror, which occurs during non-REM sleep, Schredl says.

Keyword: Sleep
Link ID: 28946 - Posted: 10.07.2023

By Katherine Harmon Courage On the surface, sleep seems obvious, essential. It comes in long, languid, predictable waves, washing over humans and elephants, birds and fish and beetles. It comes bearing restoration, repair, learning. It follows an ancestral rhythm played deep within our cells, cued by the movement of our planet around our star. Perhaps we could believe this nice, simple fantasy, were it not for an irksome little eyeless fish. More than a decade ago, this fish—the Mexican tetra (Astyanax mexicanus)—caught the eye of a graduate student at New York University. It was not new to science—it had been the subject of fascination for aquarists and researchers for decades, who marveled at its ghostly appearance and the splash of skin where its eyes should have been. But other quirks of the fish turned out to be even more mysterious. In Manhattan, the fish were far from their place of origin: a collection of unassuming caves strung through northeastern Mexico. Inside these caves, it is pitch dark, always cool, quiet, and rather boring. A seemingly perfect place to sleep. So Erik Duboué, the curious graduate student, decided to test if these fish showed any unusual sleep habits. One night in 2009, he made a 2 a.m. visit to the lab and noticed something strange about these sightless fish: They seemed wide awake. On further investigation, he found that despite their soporific native environs, they actually hardly sleep at all. In fact, he discovered, they doze just about three and a half hours out of each 24-hour period. And their bouts of sleep seem to come on entirely randomly and only in brief spurts. Curiously, these eyeless cavefish seem to have been flourishing on this quiescence interruptus for hundreds of thousands of years. “What you have is a fish that is completely healthy—it just doesn’t need to sleep,” says Duboué, who is now a molecular geneticist at Florida Atlantic University. Since then, Duboué and others have been studying the strange sleep of these wakeful creatures—prodding them in the lab to rouse them from their occasional slumber and plumbing their DNA. Combined with investigations into other animals, as well as some peculiar experiments that have sent humans to sleep in caves, scientists are uncovering new, closely guarded truths about sleep that have eluded us in our bright, rhythmic world. © 2023 NautilusNext Inc.

Keyword: Sleep; Evolution
Link ID: 28941 - Posted: 10.03.2023

By Stephanie Pappas If you’ve ever awoken from a vivid dream only to find that you can’t remember the details by the end of breakfast, you’re not alone. People forget most of the dreams they have—though it is possible to train yourself to remember more of them. Dreaming happens mostly (though not always exclusively) during rapid eye movement (REM) sleep. During this sleep stage, brain activity looks similar to that in a waking brain, with some very important differences. Key among them: during REM sleep, the areas of the brain that transfer memories into long-term storage—as well as the long-term storage areas themselves—are relatively deactivated, says Deirdre Barrett, a dream researcher at Harvard Medical School and author of the book The Committee of Sleep (Oneiroi Press, 2001). This may be a side effect of REM’s role in memory consolidation, according to a 2019 study on mice in the journal Science. Short-term memory areas are active during REM sleep, but those only hang on to memories for about 30 seconds. “You have to wake up from REM sleep, generally, to recall a dream,” Barrett says. If, instead, you pass into the next stage of sleep without rousing, that dream will never enter long-term memory. REM sleep occurs about every 90 minutes, and it lengthens as the night drags on. The first REM cycle of the night is typically just a few minutes long, but by the end of an eight-hour night of sleep, a person has typically been in the REM stage for a good 20 minutes, Barrett says. That’s why the strongest correlation between any life circumstance and your memory of dreams is the number of hours you’ve slept. If you sleep only six hours, you’re getting less than half of the dream time of an eight-hour night, she says. Those final hours of sleep are the most important for dreaming. And people tend to remember the last dream of the night—the one just before waking. © 2023 Scientific American

Keyword: Sleep; Learning & Memory
Link ID: 28939 - Posted: 10.03.2023

By Meghan Rosen Maybe TikTok showed you people putting a little tape on their lips. Or maybe Instagram served you ads for sticky mouth strips. On social media and beyond, a trend called mouth taping is keeping people’s mouths shut at night — helping them breathe through their nose. Zack Ford, age 38, first tried the trend last month, after recovering from surgery for a deviated septum. Surgery improved his nasal breathing, but at night, he was still sucking air through his lips. In the mornings, Ford says, he’d wake up with a dry mouth and a scratchy throat. Ford brought up mouth taping during an appointment with his doctor, who didn’t think there was harm in trying. That evening, Ford placed a small square of surgical tape over the middle of his lips and settled into bed. It was the best night’s sleep he’s had in recent memory, he says. “When I woke up, I was like, ‘Holy shit this works!’” Mouth taping’s benefits have been touted for everything from the dental to the somnial. People may seal their mouths shut to prevent teeth grinding, bad breath, snoring and sleep apnea — or even to boost fitness or get a stronger jaw. But there’s little data yet to support such claims, dentist Jonathan Quigley wrote in a June 23 letter in the British Dental Journal. Before advising patients, Quigley, who works at a dental clinic in England, would like to see more studies and have a better understanding of the potential risks and benefits. Could taping the mouth improve people’s sleep? Some evidence suggests that mouth taping may have merit for helping treat at least one ailment: sleep apnea. Even here, though, the science is skimpy, and the methods are varied. From a thin strip on the lips to a black patch across the mouth, tape types and techniques can differ between people, brands and studies, making it difficult to draw broad conclusions. © Society for Science & the Public 2000–2023.

Keyword: Sleep
Link ID: 28927 - Posted: 09.27.2023

By Carolyn Wilke Young jumping spiders dangle by a thread through the night, in a box, in a lab. Every so often, their legs curl and their spinnerets twitch — and the retinas of their eyes, visible through their translucent exoskeletons, shift back and forth. “What these spiders are doing seems to be resembling — very closely — REM sleep,” says Daniela Rößler, a behavioral ecologist at the University of Konstanz in Germany. During REM (which stands for rapid eye movement), a sleeping animal’s eyes dart about unpredictably, among other features. In people, REM is when most dreaming happens, particularly the most vivid dreams. Which leads to an intriguing question. If spiders have REM sleep, might dreams also unfold in their poppy-seed-size brains? Rößler and her colleagues reported on the retina-swiveling spiders in 2022. Training cameras on 34 spiders, they found that the creatures had brief REM-like spells about every 17 minutes. The eye-darting behavior was specific to these bouts: It didn’t happen at times in the night when the jumping spiders stirred, stretched, readjusted their silk lines or cleaned themselves with a brush of a leg. Though the spiders are motionless in the run-up to these REM-like bouts, the team hasn’t yet proved that they are sleeping. But if it turns out that they are — and if what looks like REM really is REM — dreaming is a distinct possibility, Rößler says. She finds it easy to imagine that jumping spiders, as highly visual animals, might benefit from dreams as a way to process information they took in during the day. Young jumping spiders have translucent skin. Behind their eyes, tube-shaped retinas move as the spiderlings look about. As shown in this sped-up video, researchers have also observed such retinal tube-shifting behavior in resting — possibly sleeping — spiders. In these intermittent, active bouts, the animals’ legs curl and their spinnerets twitch — suggesting that spiders may experience something like REM sleep. © 2023 Annual Reviews

Keyword: Sleep; Evolution
Link ID: 28896 - Posted: 09.07.2023

By Maria Temming When Christopher Mazurek realizes he’s dreaming, it’s always the small stuff that tips him off. The first time it happened, Mazurek was a freshman at Northwestern University in Evanston, Ill. In the dream, he found himself in a campus dining hall. It was winter, but Mazurek wasn’t wearing his favorite coat. “I realized that, OK, if I don’t have the coat, I must be dreaming,” Mazurek says. That epiphany rocked the dream like an earthquake. “Gravity shifted, and I was flung down a hallway that seemed to go on for miles,” he says. “My left arm disappeared, and then I woke up.” Most people rarely if ever realize that they’re dreaming while it’s happening, what’s known as lucid dreaming. But some enthusiasts have cultivated techniques to become self-aware in their sleep and even wrest some control over their dream selves and settings. Mazurek, 24, says that he’s gotten better at molding his lucid dreams since that first whirlwind experience, sometimes taking them as opportunities to try flying or say hi to deceased family members. Other lucid dreamers have used their personal virtual realities to plumb their subconscious minds for insights or feast on junk food without real-world consequences. But now, scientists have a new job for lucid dreamers: to explore their dreamscapes and report out in real time. Dream research has traditionally relied on reports collected after someone wakes up. But people often wake with only spotty, distorted memories of what they dreamed. The dreamers can’t say exactly when events occurred, and they certainly can’t tailor their dreams to specific scientific studies. © Society for Science & the Public 2000–2023.

Keyword: Sleep; Consciousness
Link ID: 28891 - Posted: 08.30.2023

By Christina Caron About one in four adults in the United States develops symptoms of insomnia each year. In most cases, these are short-lived, caused by things like stress or illness. But one in 10 adults is estimated to have chronic insomnia, which means difficulty falling or staying asleep at least three times a week for three months or longer. Sleep deprivation doesn’t just create physical health problems, it can also harm our minds. A recent poll from the National Sleep Foundation, for example, found a link between poor sleep health and depressive symptoms. In addition, studies have shown that a lack of sleep can lead otherwise healthy people to experience anxiety and distress. Fortunately, there is a well-studied and proven treatment for insomnia that generally works in eight sessions or less: cognitive behavioral therapy for insomnia, or C.B.T.-I. If you cannot find a provider, C.B.T.-I. instruction is easy to access online. Yet it is rarely the first thing people try, said Aric Prather, a sleep researcher at the University of California, San Francisco, who treats patients with insomnia. Instead, they often turn to medication. According to a 2020 survey from the Centers for Disease Control, more than 8 percent of adults reported taking sleep medication every day or most days to help them fall or stay asleep. Studies have found that C.B.T.-I. is as effective as using sleep medications in the short term and more effective in the long term. Clinical trial data suggests that as many as 80 percent of the people who try C.B.T.-I. see improvements in their sleep and most patients find relief in four to eight sessions, even if they have had insomnia for decades, said Philip Gehrman, the director of the Sleep, Neurobiology and Psychopathology lab at the University of Pennsylvania. © 2023 The New York Times Company

Keyword: Sleep
Link ID: 28890 - Posted: 08.30.2023

Nicola Davis Taking a short nap during the day may help to protect the brain’s health as it ages, researchers have suggested after finding that the practice appears to be associated with larger brain volume. While previous research has suggested long naps could be an early symptom of Alzheimer’s disease, other work has revealed that a brief doze can improve people’s ability to learn. Now researchers say they have found evidence to suggest napping may help to protect against brain shrinkage. That is of interest, the team say, as brain shrinkage, a process that occurs with age, is accelerated in people with cognitive problems and neurodegenerative diseases, with some research suggesting this may be related to sleep problems. “In line with these studies, we found an association between habitual daytime napping and larger total brain volume, which could suggest that napping regularly provides some protection against neurodegeneration through compensating for poor sleep,” the researchers note. Writing in the journal Sleep Health, researchers at UCL and the University of the Republic in Uruguay report how they drew on data from the UK Biobank study that has collated genetic, lifestyle and health information from 500,000 people aged 40 to 69 at recruitment. The team used data from 35,080 Biobank participants to look at whether a combination of genetic variants that have previously been associated with self-reported habitual daytime napping are also linked to brain volume, cognition and other aspects of brain health. © 2023 Guardian News & Media Limited

Keyword: Sleep; Development of the Brain
Link ID: 28829 - Posted: 06.21.2023

By Emily Underwood It’s a classic science fiction trope: Astronauts on an interstellar journey are kept in sleek, refrigerated pods in a state of suspended animation. Although such pods remain purely fictional, scientists have pursued research into inducing a hibernation-like state in humans to lessen the damage caused by medical conditions such as heart attacks and stroke, and to reduce the stress and costs of future long-distance space sojourns. In a study published today in Nature Metabolism, scientists report that they can trigger a similar state in mice by targeting part of their brain with pulses of ultrasound. Some experts are calling it a major technical step toward achieving this feat in humans, whereas others say it’s a stretch to extrapolate the results to our species. "It’s an amazing paper,” says Frank van Breukelen, a biologist who studies hibernation at the University of Nevada, Las Vegas and co-authored an editorial accompanying the study. The work builds on a flurry of recent studies that pinpoint specific populations of neurons in a region called the preoptic area (POA) of the hypothalamus. These cells act like an on-off switch for “torpor”—a sluggish, energy-saving state the animals enter when they’re dangerously cold or malnourished. In previous studies, scientists genetically engineered these neurons to respond to light or certain chemicals, and found they could cause mice to enter a torpid state even when they were warm and well-fed. Such invasive techniques can’t be easily translated to people, however, Breukelen notes. “That’s really not going to happen in people.” The new ultrasound study, led by bioengineer Hong Chen and her team at Washington University in St. Louis required no genetic engineering. Chen knew from previous research that some neurons have specialized pores called TRPM2 ion channels that change shape in response to ultrasonic waves, including the subset of POA cells that controls mouse torpor. To see what effect that had on the animals’ behavior, her team next glued miniature, speakerlike devices on the heads of mice to focus these waves on the POA.

Keyword: Sleep; Brain imaging
Link ID: 28800 - Posted: 05.27.2023

By Carolyn Wilke Costello the octopus was napping while stuck to the glass of his tank at the Rockefeller University in New York. He snoozed quietly for half an hour, and then entered a more active sleep stage, his skin cycling through colors and textures used for camouflage — typical behavior for a cephalopod. But soon things became strange. A minute later, Costello scuttled along the glass toward his tank’s sandy bottom, curling his arms over his body. Then he spun like a writhing cyclone. Finally, Costello swooped down and clouded half of his tank with ink. As the tank’s filtration system cleared the ink, Eric Angel Ramos, a marine scientist, noticed that Costello was grasping a pipe with unusual intensity, “looking like he was trying to kill it,” he said. “This was not a normal octopus behavior,” said Dr. Ramos, who is now at the University of Vermont. It’s not clear when or if Costello woke up during the episode, Dr. Ramos said. But afterward, Costello returned to normal, eating and later playing with his toys. “We were completely dumbfounded,” said Marcelo O. Magnasco, a biophysicist at Rockefeller. Perhaps Costello was having a nightmare, he and a team of researchers speculated. They shared this idea and other possible explanations in a study uploaded this month to the bioRxiv website. It has yet to be formally reviewed by other scientists. After the incident, Dr. Ramos reviewed the footage of Costello’s activity, which was recorded as part of a behavior and cognition study (the lab was also observing another octopus, Abbott; both were named after the heptapod aliens in the movie “Arrival”). In total, the team found three more shorter instances that appeared similar. To Dr. Magnasco, the behaviors exhibited in Costello’s longest spell evoked the acting out of a dream. The curling of arms over his body looked like a defensive posture, he said. In the footage, the animal is seen perhaps trying to make himself look larger, and then he tries an evasive maneuver — inking. When he fails to escape, it seems like Costello seeks to subdue a threat by strangling the pipe, Dr. Magnasco said, adding, “This is the sequence of a fight.” © 2023 The New York Times Company

Keyword: Sleep; Evolution
Link ID: 28798 - Posted: 05.27.2023

Nicola Davis Science correspondent From loud snores to twitching paws, dogs often appear to have a penchant for a good snooze. But researchers have said elderly canines with dementia appear to spend less time slumbering than those with healthy brains – mirroring patterns seen in humans. It has long been known that people with dementia can experience sleep problems, including finding it harder to get to sleep. Researchers have also found changes in the brainwaves of people with dementia during sleep – including decreased slow brain waves that occur during non-rapid eye movement deep sleep. These are important in memory consolidation and appear to be linked to the activity of the brain’s system for clearing away waste. Now it seems sleep impairment may occur in dogs experiencing a condition similar to dementia in humans. “Changes in sleep habits should be expected in older dogs, and could be a harbinger of decline in cognition,” said Prof Natasha Olby, senior author of a study at North Carolina State University. Writing in the journal Frontiers in Veterinary Science, Olby and colleagues reported on their study of 28 dogs aged between 10 and 16 years old. The canines’ brainwaves were recorded by electroencephalogram (EEG) while the dogs took a two-hour afternoon nap. The researchers also assessed owners’ answers to a questionnaire and each dog’s performance on a range of problem-solving, memory and attention tasks, to provide a score indicating whether the dog had, or was at risk of, canine dementia. Twenty of the dogs were deemed to have cognitive impairment, with this judged to be severe in eight of them. Combining their data, the team found dogs with higher dementia scores took longer to fall asleep and spent less time sleeping. © 2023 Guardian News & Media Limited

Keyword: Alzheimers; Sleep
Link ID: 28760 - Posted: 04.29.2023

by Kyle H. Kallman In 2010, when I was 18, a sleep study confirmed what kids at sleepovers and camp, and my freshman-year dorm mate who slept with headphones blaring heavy metal, already knew: I snored, and very loudly. The breathing passages in my nose, throat and mouth weren’t staying open, forcing my brain to wake up from deep sleep and open my airways. Over 30 times an hour. I awoke each morning exhausted. At the time, I thought it was normal to feel terrible every morning. “He’s a typical teenager,” said my mom when I slept in until the evening on weekends. My dad’s solution was pouring water on me so I could “seize the day!” I was a regular night owl who hated mornings. I never felt fully awake until the afternoon. Kyle H. Kallman wears a mask for his CPAP machine. (Kyle H. Kallman) But my physician suggested I get tested for sleep apnea since my levels of sleepiness were off the charts, even for a teen. And he warned me that the health effects of sleep apnea over time could be bad: stroke, heart problems, diabetes, and in some cases, even a shortened life span. A specialist looked at my test and said I needed a continuous positive airway pressure machine, a clunky contraption that sits beside your bed and straps on your face at night, providing a little constant air pressure that basically keeps your airways open as you sleep. No way was I going to do that. Sleep apnea seemed like a problem for old people — most CPAP users start at age 55 — and I was living in a college dorm and dating. If I ever brought somebody back to my college dorm room, they’d see the dorky machine on my nightstand and any possibility of romance would end. Besides, I didn’t think snoring was a big deal — I didn’t hear it.

Keyword: Sleep
Link ID: 28759 - Posted: 04.29.2023

Ruth Ogden A year and half alone in a cave might sound like a nightmare to a lot of people, but Spanish athlete Beatriz Flamini emerged with a cheerful grin and said she thought she had more time to finish her book. She had almost no contact with the outside world during her impressive feat of human endurance. For 500 days, she documented her experiences to help scientists understand the effects of extreme isolation. One of the first things that became apparent on April 12 2023 when she emerged from the cave was how fluid time is, shaped more by your personality traits and the people around you than a ticking clock. When talking to reporters about her experiences, Flamini explained she rapidly lost her sense of time. The loss of time was so profound that, when her support team came to retrieve her, she was surprised that her time was up, instead believing she had only been there for 160-170 days. Our actions, emotions and changes in our environment can have powerful effects on the way in which our minds process time. For most people, the rising and setting of the sun mark the passing of days, and work and social routines mark the passing of hours. In the darkness of an underground cave, without the company of others, many signals of passing of time will have disappeared. So Flamini may have become more reliant on psychological processes to monitor time. One way in which we keep track of the passage of time is memory. If we don’t know how long we have been doing something for, we use the number of memories formed during the event as an index to the amount of time that has passed. The more memories we form in an event or era, the longer we perceive it to have lasted. © 2010–2023, The Conversation US, Inc.

Keyword: Attention; Biological Rhythms
Link ID: 28755 - Posted: 04.26.2023

By Carolyn Todd Any sleep tracker will show you that slumber is far from a passive affair. And no stage of sleep demonstrates that better than rapid eye movement, or REM, commonly called dream sleep. “It’s also called paradoxical sleep or active sleep, because REM sleep is actually very close to being awake,” said Dr. Rajkumar Dasgupta, a sleep medicine and pulmonary specialist at the Keck School of Medicine of the University of Southern California. Before scientists discovered REM sleep in the 1950s, it wasn’t clear that much of anything was happening in the brain at night. Researchers today, however, understand sleep as a highly active process composed of very different types of rest — including REM, which in some ways doesn’t seem like rest at all. While the body typically remains “off” during REM sleep, the brain is very much “on.” It’s generating vivid dreams, as well as synthesizing memories and knowledge. Scientists are still working to unravel exactly how this strange state of consciousness works. “It is fair to say that there is a lot left to learn about REM sleep,” Dr. Dasgupta said. But from what researchers do understand, REM is critical to our emotional health and brain function — and potentially even our longevity. Where does REM sleep fall in the sleep cycle? Throughout the night, “We’re going in and out of this rhythmic, symphonic pattern of the various stages of sleep: non-REM 1, 2, 3 and REM,” said Rebecca Robbins, an instructor in medicine at Harvard Medical School and an associate scientist in the division of sleep and circadian disorders at Brigham and Women’s Hospital. As you doze off, you enter the first stage of non-REM. This lasts less than 10 minutes and is considered a light sleep. Your breathing and heart rate decelerate and your muscles relax as you slip into the second stage of non-REM sleep, where your body temperature drops and your brain waves get slower. Then you enter the third stage, known as deep sleep, when your body repairs your bones and muscles, strengthens your immune system, releases hormones and restores your energy. © 2023 The New York Times Company

Keyword: Sleep
Link ID: 28750 - Posted: 04.26.2023

By Annie Roth It long seemed as though African elephants were the champions of the all-nighter. They can get by on about two hours of sleep. Other mammals need much more, like koalas (20 hours) or you (at least seven plus at least one strong cup of coffee). But the largest living mammals on land have some competition at sea. Northern elephant seals are also able to sustain themselves on about two hours’ sleep, according to a study published Thursday in the journal Science. The study found that Northern elephant seals sleep far less at sea than they do on land, and the z’s they do catch at sea are caught hundreds of feet below the ocean’s surface. The study’s authors believe that sleeping in the deep allows the seals to power-nap without being eaten by prowling predators. Northern elephant seals, which are found along the West Coast, are champion divers that can descend to depths of 2,500 feet and stay under for about two hours. They are not as big as elephants, but males can weigh as much as a car and stretch 13 feet long. To maintain their blubbery bulk, Northern elephant seals must spend around seven months at sea each year, gorging on fish and squid. During these epic voyages, the seals are vulnerable to predation by great white sharks and killer whales. Some marine mammals, such as dolphins and fur seals, can rest half of their brain at a time. This type of slumber, known as unihemispheric sleep, enables some mammals at sea to snooze with one eye open, literally, which prevents predators from catching them off guard. However, elephant seals sleep like us, shutting down their brains completely. Jessica Kendall-Bar, now a postdoctoral fellow at the Scripps Institution of Oceanography in San Diego, wondered how Northern ​​elephant seals managed to sleep, given how much time they need to spend eating and avoiding being eaten while at sea. © 2023 The New York Times Company

Keyword: Sleep; Evolution
Link ID: 28746 - Posted: 04.22.2023

By Simon Makin Waves of cerebrospinal fluid which normally wash over brains during sleep can be made to pulse in the brains of people who are wide awake, a new study finds. The clear fluid may flush out harmful waste, such as the sticky proteins that accumulate in Alzheimer’s disease (SN: 7/15/18). So being able to control the fluid’s flow in the brain could possibly one day have implications for treating certain brain disorders. “I think this [finding] will help with many neurological disorders,” says Jonathan Kipnis, a neuroscientist at Washington University in St. Louis who was not involved in the study. “Think of Formula One. You can have the best car and driver, but without a great maintenance crew, that driver will not win the race.” Spinal fluid flow in the brain is a major part of that maintenance crew, he says. But he and other researchers, including the study’s authors, caution that any potential therapeutic applications are still far off. In 2019, neuroscientist Laura Lewis of Boston University and colleagues reported that strong waves of cerebrospinal fluid wash through our brains while we slumber, suggesting that one unappreciated role of sleep may be to give the brain a deep clean (SN: 10/31/19). And the team showed that the slow neural oscillations that characterize deep, non-REM sleep occur in lockstep with the waves of spinal fluid through the brain. “If you drop your clothes in a bath of water, eventually dirt will come out. But if you swish them back and forth, things are moving much more effectively,” Lewis says. “That’s the analogy I think of.” These flows were far larger than the small, rhythmic influences that one’s breathing and heartbeat have on spinal fluid. © Society for Science & the Public 2000–2023.

Keyword: Sleep
Link ID: 28727 - Posted: 04.01.2023

By Meghan Rosen The patient arrived at the hospital one hot night in Masi-Manimba, an agricultural town unfurled along the Democratic Republic of the Congo’s Lukula River. He couldn’t speak, he couldn’t walk, he was conscious but “barely could make … gestures,” says Béatrice Kasita, a nurse who was there when he came in. She remembers his deformed posture, how his body curved into a fetal position. He was also unusually drowsy — a telltale sign of his illness. The patient, a 27-year-old man, had been brought in by a medical team screening villagers for sleeping sickness, a deadly parasitic disease spread via the bite of a blood-feeding fly. Since the first case report in the late 14th century, the illness has ebbed and flowed in sub-Saharan Africa. Across the continent, the predominant form of sleeping sickness shows up in about two dozen countries, most cases now occurring in the DRC. The disease is a nightmarish scourge that can maim the brain and ultimately kill. But today, cases hover near an all-time low. In 2021, the World Health Organization reported just 747 cases of the predominant form, down from more than 37,000 in 1998. That precipitous plunge came out of decades of work, millions of screenings, spinal taps upon spinal taps, toxic treatments and the rapid rise of safer though often burdensome ones, countless IV infusions, long hospital days and nights, medicine lugged to remote villages, and communities on constant alert for sleeping sickness’s insidious symptoms. Now, a promising drug has fanned hope for halting transmission of the disease. Called acoziborole, the drug is taken by mouth in just a single dose. Kasita’s patient, who arrived at the hospital in June 2017, was among the first to try it. © Society for Science & the Public 2000–2023.

Keyword: Sleep
Link ID: 28715 - Posted: 03.23.2023

By Katherine Harmon Courage We all might wish for minds as retentive as a hard drive. Memory file created. Saved. Ready for access at any time. But don’t yet go wishing for the memory performance of AI. Artificial neural networks are prone to a troublesome glitch known, evocatively, as catastrophic forgetting. These seemingly tireless networks can keep learning tasks day and night. But sometimes, once a new task is learned, any recollection of an old task vanishes. It’s as if you learned to play tennis decently well, but after being taught to play water polo, you suddenly had no recollection of how to swing a racket. This apparent network overload put an idea in the head of Maxim Bazhenov, a professor who studies computational neuroscience and sleep at the University of California San Diego School of Medicine. Perhaps the spiking neural networks he was working with simply needed a rest. In natural sleep, he had seen that the same basic brain processes occur in humans and in honeybees, working over information accumulated during waking moments. “That machinery presumably was doing something useful” in order to be conserved across evolutionary paths, he says. So, he thought, why not try a similar state for the machines. The idea was to simply provide the artificial neural networks with a break from external stimuli, to instruct them to go into a sort of rest state. Like the dozing human brain, the networks were still active, but instead of taking in new information, they were mulling the old stuff, consolidating, surfacing patterns.

Keyword: Sleep; Learning & Memory
Link ID: 28709 - Posted: 03.18.2023