Ian Sample Science editor It’s never a great look. The morning meeting is in full swing but thanks to a late night out your brain switches off at the precise moment a question comes your way. Such momentary lapses in attention are a common problem for the sleep deprived, but what happens in the brain in these spells of mental shutdown has proved hard to pin down. Now scientists have shed light on the process and found there is more to zoning out than meets the eye. The brief loss of focus coincides with a wave of fluid flowing out of the brain, which returns once attention recovers. “The moment somebody’s attention fails is the moment this wave of fluid starts to pulse,” said Dr Laura Lewis, a senior author on the study at MIT in Boston. “It’s not just that your neurons aren’t paying attention to the world, there’s this big change in fluid in the brain at the same time.” Lewis and her colleague Dr Zinong Yang investigated the sleep-deprived brain to understand the kinds of attention failures that lead drowsy drivers to crash and tired animals to become a predator’s lunch. In the study, 26 volunteers took turns to wear an EEG cap while lying in an fMRI scanner. This enabled the scientists to monitor the brain’s electrical activity and physiological changes during tests in which people had to respond as quickly as possible to hearing a tone or seeing crosshairs on a screen turn into a square. Each volunteer was scanned after a restful night’s sleep at home and after a night of total sleep deprivation supervised by scientists at the laboratory. Unsurprisingly, people performed far worse when sleep deprived, responding more slowly or not at all. © 2025 Guardian News & Media Limited

Keyword: Sleep; Attention
Link ID: 29993 - Posted: 11.01.2025

Imma Perfetto Anyone who has ever struggled through the day following a poor night’s sleep has had to wrench their attention back to the task at hand after their mind drifted off unexpectedly. Now, researchers have pinpointed exactly what causes these momentary failures of attention. The new study in Nature Neuroscience found that the brains of sleep-deprived people initiate waves of cerebrospinal fluid (CSF), the liquid which cushions the brain, which dramatically impaired attention. This process usually happens during sleep. The rhythmic flow of CSF into and out of the brain carries away protein waste which has built up over the course of the day. When this is maintenance interrupted due to lack of sleep, it seems the brain attempts to play catch up during its waking hours. “If you don’t sleep, the CSF waves start to intrude into wakefulness where normally you wouldn’t see them,” says study senior author Laura Lewis of Massachusetts Institute of Technology’s (MIT) Institute for Medical Engineering and Science. “However, they come with an attentional trade off, where attention fails during the moments that you have this wave of fluid flow. “The results are suggesting that at the moment that attention fails, this fluid is actually being expelled outward away from the brain. And when attention recovers, it’s drawn back in.” © Copyright CSIRO

Keyword: Sleep; Attention
Link ID: 29992 - Posted: 11.01.2025

Joel Snape All vertebrates yawn, or indulge in a behaviour that’s at least recognisable as yawn-adjacent. Sociable baboons yawn, but so do semi-solitary orangutans. Parakeets, penguins and crocodiles yawn – and so, probably, did the first ever jawed fish. Until relatively recently, the purpose of yawning wasn’t clear, and it’s still contested by researchers and scientists. But this commonality provides a clue to what it’s really all about – and it’s probably not what you’re expecting. “When I poll audiences and ask: ‘Why do you think we yawn?’, most people suggest that it has to do with breathing or respiration and might somehow increase oxygen in the blood,” says Andrew Gallup, a professor in behavioural biology at Johns Hopkins University. “And that’s intuitive because most yawns do have this clear respiratory component, this deep inhalation of air. However, what most people don’t realise is that that hypothesis has been explicitly tested and shown to be false.” To test the idea that we yawn to bring in more oxygen or expel excess carbon dioxide, studies published in the 1980s manipulated the levels of both gases in air inhaled by volunteers – and they found that while changes did significantly affect other respiratory processes, they didn’t influence the regularity of yawns. There also doesn’t seem to be any systematically measurable difference in the yawning behaviour of people suffering from illnesses associated with breathing and lung function – which is what you would expect if yawns were respiration-related. This, more or less, was where Gallup came to the subject. “When I was pursuing my honours thesis, my adviser at the time said, well, why not study yawning, because nobody knows why we do it?” he says. “That was intriguing – we knew it had to serve some underlying physiological function. So I started to examine the motor action pattern it involves – this extended gaping of the jaw that’s accompanied by this deep inhalation of air, followed by a rapid closure of the jaw and a quicker exhalation. And it occurred to me that this likely has important circulatory consequences that are localised to the skull.” © 2025 Guardian News & Media Limited

Keyword: Emotions; Sleep
Link ID: 29990 - Posted: 10.29.2025

Rachel Fieldhouse Slow, sleep-like brain waves persist in part of the brain that has been surgically disconnected from the rest of the organ even though the person is awake. The findings1, published in PLoS Biology, add to researchers’ understanding of what conscious and unconscious brain states look like. Children with severe epilepsy who do not respond to medication can undergo a surgical procedure called a hemispherotomy. During surgery, clinicians disconnect the part of the brain in which seizures originate from the rest of the brain, stopping them from spreading. The disconnected tissue is left in the skull and has an intact blood supply. The team wanted to find out whether the disconnected part has some form of awareness — or was capable of exhibiting consciousness, says co-author Marcello Massimini, a neurophysiology researcher at the University of Milan in Italy. “The question arises because we have no access” to the disconnected region, he says, adding that it was unclear what happens once part of the brain is isolated. Studies investigating consciousness are difficult because there is no consensus on what conscious and unconscious states in the brain look like, says Ariel Zeleznikow-Johnston, a neuroscientist at Monash University in Melbourne, Australia. “There’s no generally accepted definitive signatures of consciousness in terms of electrical readings or brain activity,” he adds. Even defining unconsciousness is challenging, because activities associated with consciousness, such as remembering dreams, can occur during states associated with unconsciousness, such as sleep or anaesthesia, Massimini says. © 2025 Springer Nature Limited

Keyword: Sleep
Link ID: 29980 - Posted: 10.22.2025

By Yasemin Saplakoglu The pillow is cold against your cheek. Your upstairs neighbor creaks across the ceiling. You close your eyes; shadows and light dance across your vision. A cat sniffs at a piece of cheese. Dots fall into a lake. All this feels very normal and fine, even though you don’t own a cat and you’re nowhere near a lake. You’ve started your journey into sleep, the cryptic state that you and most other animals need in some form to survive. Sleep refreshes the brain and body in ways we don’t fully understand: repairing tissues, clearing out toxins and solidifying memories. But as anyone who has experienced insomnia can attest, entering that state isn’t physiologically or psychologically simple. To fall asleep, “everything has to change,” said Adam Horowitz (opens a new tab), a research affiliate in sleep science at the Massachusetts Institute of Technology. The flow of blood to the brain slows down, and the circulation of cerebrospinal fluid speeds up. Neurons release neurotransmitters that shift the brain’s chemistry, and they start to behave differently, firing more in sync with one another. Mental images float in and out. Thoughts begin to warp. “Our brains can really rapidly transform us from being aware of our environments to being unconscious, or even experiencing things that aren’t there,” said Laura Lewis (opens a new tab), a sleep researcher at MIT. “This raises deeply fascinating questions about our human experience.” It’s still largely mysterious how the brain manages to move between these states safely and efficiently. But studies targeting transitions both into and out of sleep are starting to unravel the neurobiological underpinnings of these in-between states, yielding an understanding that could explain how sleep disorders, such as insomnia or sleep paralysis, can result when things go awry. Sleep has been traditionally thought of as an all-or-nothing phenomenon, Lewis said. You’re either awake or asleep. But the new findings are showing that it’s “much more of a spectrum than it is a category.” © 2025 Simons Foundation

Keyword: Sleep
Link ID: 29974 - Posted: 10.18.2025

Vladyslav Vyazovskiy After decades of research, there is still no clearly articulated scientific consensus on what sleep is or why it exists. Yet whenever sleep comes up as a topic of discussion, it is quickly reduced to its necessity and importance. Popular media remind us of what can, and will, go wrong if we do not sleep enough, and serve up some handy tips on how to overcome insomnia. Discussed exclusively in utilitarian terms, we are force-fed the idea that sleep exists solely for our immediate benefit. Is this really all we ever want to know about a third of our existence? Sleep is perhaps the biggest blind spot, or the longest blind stretch, if you will, of our life. Naturally, the health and societal implications of sleep are huge: from technogenic disasters caused by tiredness, to sleep deprivation as a form of torture or weapon of war, and to sleep disorders, some of which inflict so much suffering that they compete with chronic pain. However, in my opinion, to say sleep is important is to miss the point entirely. Sleep is the single most bizarre experience that happens to all of us, against our will, every day. The disconnect between old questions about sleep that have remained open for centuries and new, increasingly sophisticated technologies applied to solve them is ever growing. The predominant view is that sleep provides some sort of restoration for the brain or the body: what goes awry – out of balance – in waking is almost magically recalibrated by sleep. At the centre of this narrative is the individual-who-sleeps, a lone castaway, locked in a permanent, inexorable cycle of sleeping and waking, without hope of breaking free (except in death). From the moment of opening one’s eyes, the clock starts ticking, and there is a price to pay for every minute of wakeful time, measured precisely in proportion to the transgression of staying awake. Like a snake eating its own tail, waking and sleep consume each other in an endless cycle, without beginning or end. There is no mercy, and lack of sleep can be paid back only by sleep. The image of burning a candle at both ends endures. Despite vast technological advances in recent years, exponential growth in our understanding of nature and the cosmos, and major breakthroughs in biology and medicine, there is still no unified theory of sleep. I find myself pondering whether it is time to step back and seek a different angle. Medieval manuscript illustration depicting people sleeping in three beds, with two standing figures in dialogue beside them, and an ornate floral border. © Aeon Media Group Ltd. 2012-2025.

Keyword: Sleep
Link ID: 29971 - Posted: 10.15.2025

By Katarina Zimmer Few mammals sleep as deeply as the ampurta. When the blonde, rat-like marsupial returns to its burrow after a night of hunting in the Australian desert, it drifts into a slumber known as torpor. While many other mammals quickly burn through their energy reserves in order to maintain stable body temperatures as they fall asleep, ampurtas allow their bodies to cool down to as low as 50 degrees Fahrenheit, saving energy critical to survival in this harsh desert environment. “I’ve held some when they’re in torpor, and they feel like they’ve been in a freezer,” says wildlife ecologist Dympna Cullen of the University of New South Wales in Sydney. Instead of using their own energy to warm up again, upon waking, the animals drag themselves to the mouths of their burrows to soak up the morning sun. Some scientists say this energy-saving trick helped the ampurta—once thought doomed to extinction—to make a comeback during a severe drought. In what they call a “rare and hopeful conservation signal,” the authors document in a new study in Biological Conservation how, during a two-year drought that lasted from 2017 to 2019—one of the region’s harshest droughts on record—the vulnerable marsupials actually significantly extended their range, reclaiming a large chunk of lost habitat. “Everything crashes during a drought,” Cullen says, “so it was quite unexpected that not only were [ampurtas] increasing in abundance but also increasing their area of occupancy by quite a significant amount during a drought.” Like many other Australian mammals, the ampurta—the Aboriginal name for Dasycercus hillieri or the crest-tailed mulgara—once seemed like it might vanish from the Earth. Rabbits brought to Australia by European colonists in the 19th century wreaked ecological havoc on the continent. They ravaged Australia’s vegetation, robbing small native herbivores of cover and food, including some of the ampurta’s prey, such as smaller mammals. The rabbit boom also fed the spread of non-native foxes and cats, which picked off ampurtas and other native wildlife. But in 1996, the Australian government released a rabbit-killing virus to quash rabbit populations, which allowed some native species populations to recover. Ampurtas were downgraded from endangered in the mid-1990s to “vulnerable” in 2013, and eventually to a species of “least concern.” © 2025 NautilusNext Inc.,

Keyword: Sleep; Evolution
Link ID: 29949 - Posted: 10.01.2025

Lynne Peeples From TikTok videos touting mouth tape and weighted blankets, to magazines ranking insomnia-curbing pillows, sleep advice is everywhere. And it’s no wonder. People all over the world complain of insomnia and not getting enough sleep, driving a market for sleep aids worth more than US$100 billion annually. But scientists warn that online hacks and pricey tools aren’t always effective. And failed attempts to remedy the situation could have negative effects, says Andrew McHill, a circadian scientist at Oregon Health & Science University in Portland. “It could discourage people from finding help, and things could get worse,” he says. Instead, researchers point to the lessons coming from circadian science, which over the past five decades has exposed a network of biological clocks throughout the body. This timekeeping machinery ensures that physiological systems are primed to do the right things at the right times — such as defend against pathogens, digest food and sleep. But circadian clocks don’t cycle precisely on their own. To stay in sync and function optimally, they need regular calibration from sunlight, daily routines and other cues. Modern life doesn’t often cooperate. People spend much of their time indoors. They eat late into the night. They shift sleep schedules between workdays and weekends, effectively jet-lagging themselves. The toll is steep. In the short term, circadian disruption and insufficient sleep can reduce cognition, mood and reaction time. In the long term, they can increase risks of infections, diabetes, depression, dementia, cancer, heart disease and premature death. For better sleep and overall health, McHill and other scientists emphasize three basics: contrasting light and dark, consolidating mealtimes and keeping sleep times consistent. “Simply taking a walk outside during the day and reducing our light exposure in the evening could have great effect,” says McHill. © 2025 Springer Nature Limited

Keyword: Sleep
Link ID: 29948 - Posted: 10.01.2025

By Viviane Callier All animals, from jellyfish to humans, need sleep. But how these wide-ranging organisms control that need has remained a mystery. It turns out that—in fruit flies, at least—sleep might be an “inescapable consequence” of aerobic metabolism, according to a new study. Mitochondria in Drosophila’s sleep-regulating neurons sense metabolic damage that accumulates during waking hours and trigger the pressure to sleep. “It’s a really beautiful contribution,” says Keith Hengen, associate professor of biology at Washington University in St. Louis, who was not involved in the work. The study explains how the brain integrates information from a metabolic thermostat to regulate sleep pressure, Hengen says. “That’s a really hard problem, and I think they’ve nailed it.” The regulators of sleep are distinct from the function of sleep, Hengen and other sleep researchers note. Just as fullness regulates food intake, but food intake doesn’t so much serve to fill the stomach as to get calories and nutrients, “we need to make this distinction between sensing of sleep pressure and the function of sleep,” says Giorgio Gilestro, associate professor of systems neurobiology at Imperial College London, who was not involved in the new study. And with respect to sleep pressure, he adds, there are two processes at play: a well-studied circadian clock mechanism that links sleep to daylight cycles, and a less-understood homeostatic process that fine-tunes the need for sleep based on other factors. © 2025 Simons Foundation

Keyword: Sleep; Evolution
Link ID: 29923 - Posted: 09.10.2025

Nell Greenfieldboyce The early bird gets the worm, as the old saying goes. And now a lot of birds around the globe are starting their days earlier than ever, because of unnaturally bright skies caused by light pollution. "For these birds, effectively their day is almost an hour longer. They start vocalizing about 20 minutes earlier in the morning and they stop vocalizing about 30 minutes later in the evening," says Neil Gilbert, a wildlife ecologist with Oklahoma State University. That's the conclusion of a sweeping study that analyzed bird calls from over 500 bird species in multiple continents, giving researchers an unprecedented look at how human-created lights are affecting the daily lives of birds worldwide. Scientists already knew that light pollution affects birds. It can send migrating birds off course, and some observations have linked artificial lighting to unusual bird activity, including one recent report of American Robins feeding their babies in their nest at night. But Gilbert and Brent Pease, with Southern Illinois University, took a more comprehensive view, by analyzing millions of recordings of birdsong. The audio was collected by thousands of devices installed in backyards and other locations, mostly by birdwatchers and other wildlife enthusiasts, as part of a program called BirdWeather. The BirdWeather devices automatically register bird calls and use them to identify the species, mostly to let bird fans know what's flitting through their yards. © 2025 npr

Keyword: Biological Rhythms
Link ID: 29896 - Posted: 08.23.2025

By Lydia Denworth A remarkably bright pulsing dot has appeared on the monitor in front of us. We are watching, in real time, the brain activity of a graduate student named Nick, who is having an afternoon nap inside an imaging machine at the Massachusetts Institute of Technology, where Lewis has her laboratory. The bright spot first appears toward the bottom of the screen, about where Nick’s throat meets his jaw. It moves slowly upward, fades and then is followed by another bright dot. “It really comes and goes,” says Lewis, who is also affiliated with Massachusetts General Hospital. “It’s in waves.” This moving dot depicts something few people have ever seen: fresh cerebrospinal fluid flowing from the spinal cord into the brain, part of a process that researchers are now learning is vital for keeping us healthy. For decades biologists have pondered a basic problem. As human brains whir and wonder throughout the day, they generate waste—excess proteins and other molecules that can be toxic if not removed. Among those proteins are amyloid beta and tau, key drivers of Alzheimer’s disease. Until recently, it was entirely unclear how the brain takes out this potentially neurotoxic trash. In the rest of the body, garbage removal is handled initially by the lymphatic system. Excess fluid and the waste it carries move from tissue into the spleen, lymph nodes and other parts of the system, where certain particles are removed and put into the bloodstream to be excreted. It was long thought that the brain can’t use the same trick, because the so-called blood-brain barrier, a protective border that keeps infections from reaching critical neural circuitry, stops the transport of most everything in and out. © 2025 SCIENTIFIC AMERICAN,

Keyword: Sleep; Neuroimmunology
Link ID: 29895 - Posted: 08.20.2025

By Andrew Iwaniuk, Georg Striedter Sleep is the most obvious behavior that, in most animals, follows a circadian rhythm. But have you ever seen a bird asleep? Maybe you have, though they usually wake up before you get close enough to see whether they have their eyes closed. Moreover, just because an animal is still and closed its eyes, does that really mean it is sleeping? Maybe it is just resting. Conversely, might some birds sleep with one or both eyes open? Indeed, it is difficult to tell whether an animal is sleeping just by observing it. To overcome this problem, researchers may prod the animal to see whether it is less responsive at certain times of day. A more definitive method for demonstrating sleep in vertebrates is to record an animal’s brain waves (its electroencephalogram, or EEG), because these waves change significantly as an individual falls asleep and then progresses through several stages of sleep. In birds, the use of EEG recordings is essential because they can sleep with one or both eyes open, presumably so they can stay alert to threats. Ostriches, for example, tend to sleep while sitting on the ground, holding their head up high, and keeping both eyes open. They certainly look alert during this time, but EEG waves reveal that they are actually asleep Types and patterns of sleep An EEG measures the activity of many neurons simultaneously. In mammals, it is usually recorded from multiple electrodes placed over the neocortex; in birds, the electrodes are typically placed on top of the hyperpallium (aka the Wulst; see Chapter 1). In addition to performing an EEG, sleep researchers typically record the animal’s eye movements and an electromyogram (EMG), which is a measure of muscle activity, often characterized as muscle “tone.” These kinds of studies have revealed that, in mammals, the transition from the waking state to sleep is marked by a shift from EEG waves that are low in amplitude (i.e., small) and high in frequency (>20 Hz) to waves that are much larger but lower in frequency (1–4 Hz). Because the latter state is characterized by powerful low-frequency EEG waves (aka slow-wave activity), it is commonly called slow-wave sleep (SWS). The mechanisms that cause SWS are complicated and involve a variety of sleep-promoting processes. However, the large amplitude of these slow waves reflects that, during SWS, numerous neurons fire in rhythm with one another so that their electrical potentials sum when they are recorded through the EEG electrodes. © 2025 Simons Foundation

Keyword: Sleep; Evolution
Link ID: 29878 - Posted: 08.06.2025

By Kamal Nahas High-intensity yoga for less than 30 minutes, twice a week, may be the best workout routine for catching high-quality shut-eye, a new study shows. But before people jump on the yoga trend, researchers say more experiments are needed to confirm the study’s findings. While exercise in general is known to improve sleep, a meta-analysis published July 11 in Sleep and Biological Rhythms presents a broad comparison of exercise routines and their influence on sleep quality. By indirectly comparing 30 trials from about a dozen countries, researchers at Harbin Sport University in China ranked how well different exercise methods influence sleep. Yoga won out, followed by walking, resistance training and aerobic exercise. While sleep disorders can be treated with cognitive behavioral therapy or sleeping pills, these interventions don’t work for everyone. “Medications are helpful in the short-term, but some of them have negative effects on the elderly,” says Saurabh Thosar, a sleep researcher at the Oregon Institute of Occupational Health Sciences in Portland. Exercise offers an alternative, but it’s tough to tell which routine is best, making it unclear how best to prescribe it. Trials that investigate this question tend to include one or two types of exercise differing in factors such as how hard, how often or how long they were performed for. Given the global prevalence of sleep problems such as insomnia, which recent estimates say affects about 16 percent of people worldwide, there is a pressing need to find the best exercise to prescribe for a good night’s snooze. © Society for Science & the Public 2000–2025.

Keyword: Sleep
Link ID: 29877 - Posted: 08.06.2025

Katie Kavanagh How does your brain wake up from sleep? A study of more than 1,000 arousals from slumber has revealed precisely how the brain bestirs itself during the transition to alertness1 — a finding that might help to manage sleep inertia, the grogginess that many people feel when hitting the snooze button. Recordings of people as they woke from the dream-laden phase of sleep showed that the first brain regions to rouse are those associated with executive function and decision-making, located at the front of the head. A wave of wakefulness then spreads to the back, ending with an area associated with vision. The findings could change how we think of waking up, says Rachel Rowe, a neuroscientist at the University of Colorado Boulder, who was not involved with the work. The results emphasize that “falling asleep and waking up aren’t simply reverse processes, but really waking up is this ordered wave of activation that moves from the front to the back of the brain”, whereas falling asleep seems to be less linear and more gradual. The study was published today in Current Biology1. The wide-awake brain shows a characteristic pattern of electrical activity, recorded by sensors on the scalp — it looks like a jagged line made up of small, tightly packed peaks and valleys. Although the pattern looks similar during rapid eye movement (REM) sleep, when vivid dreams occur, this stage features a lack of skeletal-muscle movement. The peaks are taller during most stages of non-REM sleep, which ranges from light to very deep slumber. Scientists already knew that the ‘awakened’ signature occurs at different times in different brain regions, but common imaging techniques did not allow these patterns to be explored on a precise timescale. © 2025 Springer Nature Limited

Keyword: Sleep; Attention
Link ID: 29864 - Posted: 07.19.2025

Katie Kavanagh Scientists have identified a group of neurons that might explain the mechanism behind how stress gives rise to problems with sleep and memory. The study — published last week in The Journal of Neuroscience1 — shows that neurons in a brain area called the hypothalamus mediate the effects of stress on sleep and memory, potentially providing a new target for the treatment of stress-related sleep disorders. Previous work has shown that in the hypothalamus, neurons in a structure called the paraventricular nucleus communicate with other areas important for sleep and memory. The neurons of the paraventricular nucleus release a hormone called corticotropin and have a role in regulating stress. But the neural mechanisms underlying the effect of stress on sleep and memory have remained elusive. For co-author Shinjae Chung, a neuroscientist at the University of Pennsylvania in Philadelphia, the question of exactly how stress affects these processes is personal, because, she says, “I experience a lot of sleep problems when I’m stressed”. She adds that “when I have an exam deadline, I have a tendency to have bad sleep that really affects my score the next day”. To study how neurons in the paraventricular nucleus translate stress into sleep and memory problems, the researchers put laboratory mice through a stressful experience by physically restraining the animals in a plastic tube. The team then tested the creatures’ spatial memory and monitored their brain activity as they slept. © 2025 Springer Nature Limited

Keyword: Sleep; Stress
Link ID: 29837 - Posted: 06.21.2025

By Meredith Wadman For people who wear a cumbersome mask to bed to avoid the life-threatening, long-term effects of a serious breathing disease, the prospect of shedding the headgear for a single pill taken at bedtime has been the stuff of dreams. Now, those dreams appear likely to become reality for at least some people with obstructive sleep apnea (OSA), who stop breathing dozens or hundreds of times during the night, causing their blood oxygen to drop before they subconsciously awake. Top-line results from a large clinical trial, released this week, showed a combination of two medications in one pill stimulates muscles that keep the airway open, sharply decreasing breathing disruptions. “It’s pretty clear that this medication combination is reducing obstructive sleep apnea events. And it’s reducing the severity of oxygen drops during sleep. That is exciting,” says Sigrid Veasey, a sleep physician and neuroscientist at the University of Pennsylvania who was not involved with the study. “The effects are robust and have a good scientific basis,” she says. OSA affects an estimated 60 million to 80 million people in the United States, and about 1 billion globally. It comes with long-term risks including stroke, Alzheimer’s disease, and sudden cardiac death. And many people can’t or don’t comply with the gold standard therapy, burdensome continuous positive airway pressure (CPAP) machines that blow air into the throat to keep the airway open, requiring the nocturnal mask. Driven like many before them to search for an alternative, scientists in Boston a decade ago identified a combination of two existing medications that kept the upper airway open by jointly stimulating the relevant muscles, particularly the genioglossus, a workhorse that forms most of the base of the tongue and is critical to keeping the throat open. © 2025 American Association for the Advancement of Science.

Keyword: Sleep
Link ID: 29802 - Posted: 05.24.2025

Freda Kreier Some people can function well on little sleep.Credit: Oleg Breslavtsev/Getty Most people need around eight hours of sleep each night to function, but a rare genetic condition allows some to thrive on as little as three hours. In a study published today in the Proceedings of the National Academy of Sciences1, scientists identified a genetic mutation that probably contributes to some people’s limited sleep needs. Understanding genetic changes in naturally short sleepers — people who sleep for three to six hours every night without negative effects — could help to develop treatments for sleep disorders, says co-author Ying-Hui Fu, a neuroscientist and geneticist at the University of California, San Francisco. “Our bodies continue to work when we go to bed”, detoxifying themselves and repairing damage, she says. “These people, all these functions our bodies are doing while we are sleeping, they can just perform at a higher level than we can.” In the 2000s, Fu and her colleagues were approached by people who slept six hours or less each night. After analysing the genomes of a mother and daughter, the team identified a rare mutation in a gene that helps to regulate humans’ circadian rhythm, the internal clock responsible for our sleep–wake cycle. The researchers suggested that this variation contributed to the duo’s short sleep needs. That discovery prompted others with similar sleeping habits to contact the laboratory for DNA testing. The team now knows several hundred naturally short sleepers. Fu and her colleagues have so far identified five mutations in four genes that can contribute to the trait — although different families tend to have different mutations. Short sleeper In the latest study, the researchers searched for new mutations in the DNA of a naturally short sleeper. They found one in SIK3, a gene encoding an enzyme that, among other things, is active in the space between neurons. Researchers in Japan had previously found another mutation in Sik3 that caused mice to be unusually sleepy2. © 2025 Springer Nature Limited

Keyword: Sleep; Genes & Behavior
Link ID: 29778 - Posted: 05.07.2025

By Giorgia Guglielmi Newly formed memories change over the course of a night’s sleep, a new study in rats suggests. The results reveal that memory processing and consolidation is more complex and prolonged than previously understood, says study investigator Jozsef Csicsvari, professor of systems neuroscience at the Institute of Science and Technology Austria. Sleep has long been known to help consolidate memories, though most studies have tracked only a few hours of this process. The new work monitored memory-related brain activity patterns across almost an entire day—representing a significant step forward, says Lisa Genzel, associate professor of neuroscience at Radboud University, who wasn’t involved in the research. That’s “a heroic effort,” she says. Csicsvari and his team implanted wireless electrodes into the hippocampus of three rats and recorded neuronal activity as the animals learned to navigate a maze in search of hidden pieces of food, rested or slept for 16 to 20 hours after, and then revisited the same food locations the following day. The neurons that fired during learning became active again throughout the rest period, especially during sleep, the team found. This reactivation is a key part of memory consolidation, and it doesn’t just happen immediately after learning; instead, it continues for hours, the study shows. And while the animals slept, their brain activity patterns gradually shifted to resemble the post-sleep recall patterns—a change known as “representational drift” that likely helps the brain weave new information into what it already knows, Csicsvari says. Some neuron groups may be more involved than others in updating memories, the work showed. Some cell types remained stable, whereas others changed their activity. For example, hippocampal neurons called CA1 pyramidal cells showed distinct firing patterns during memory reactivation. And interneurons, too, appeared to play a supporting role, mirroring the changes in pyramidal cells. The team published their findings in Neuron in March. © 2025 Simons Foundation

Keyword: Sleep; Learning & Memory
Link ID: 29777 - Posted: 05.07.2025

By Lydia Denworth The rattling or whistling noises of regular snorers are famously hard on those who share their beds. Middle-aged men and people who are overweight come frequently to mind as perpetrators because they are the most common sufferers of sleep apnea, often caused by a temporarily collapsing airway that makes the person snore heavily. But recent studies in children and pregnant women have revealed that even mild snoring can negatively affect health, behavior and quality of life. “We know that disordered breathing and disturbed sleep can have myriad physiological effects,” says Susan Redline, a pulmonologist and epidemiologist at Brigham and Women’s Hospital in Boston. “More people have sleep-disordered breathing than have overt apneas. We shouldn’t forget about them.” Almost everyone snores occasionally. Allergies and respiratory infections can trigger it. When the upper airway at the back of the throat narrows, it causes the tissues there to vibrate, creating the familiar rumble. Physicians worry if people habitually snore three or more nights a week, especially if they have other red flags such as unexplained high blood pressure. The category of sleep-disordered breathing includes apnea’s total pause in breathing, shallow breaths called hypopnea, snoring without apneas, and a subtler problem called flow limitation in which the shape of the airway is narrowed but the sleeper makes no noise. The standard measure of severity is the apnea-hypopnea index (AHI), which counts pauses in breathing per hour and associated drops in oxygen levels. The normal level in adults is fewer than five pauses; more than 30 is severe. In children, 10 pauses could be considered moderately severe. © 2025 SCIENTIFIC AMERICAN,

Keyword: Sleep; Development of the Brain
Link ID: 29764 - Posted: 04.30.2025

By Michael Schulson Two years ago, at a Stop & Shop in Rhode Island, the Danish neuroscientist and physician Henriette Edemann-Callesen visited an aisle stocked with sleep aids containing melatonin. She looked around in amazement. Then she took out her phone and snapped a photo to send to colleagues back home. “It was really pretty astonishing,” she recalled recently. In Denmark, as in many countries, the hormone melatonin is a prescription drug for treating sleep problems, mostly in adults. Doctors are supposed to prescribe it to children only if they have certain developmental disorders that make it difficult to sleep — and only after the family has tried other methods to address the problem. But at the Rhode Island Stop & Shop, melatonin was available over the counter, as a dietary supplement, meaning it receives slightly less regulatory scrutiny, in some respects, than a package of Skittles. Many of the products were marketed for children, in colorful bottles filled with liquid drops and chewable tablets and bright gummies that look and taste like candy. A quiet but profound shift is underway in American parenting, as more and more caregivers turn to pharmacological solutions to help children sleep. What makes that shift unusual is that it’s largely taking place outside the traditional boundaries of health care. Instead, it’s driven by the country’s sprawling dietary supplements industry, which critics have long said has little regulatory oversight — and which may get a boost from Secretary of Health and Human Services Robert F. Kennedy Jr., who is widely seen as an ally to supplement makers. Thirty years ago, few people were giving melatonin to children, outside of a handful of controlled experiments. Even as melatonin supplements grew in popularity among adults in the late 1990s in the United States and Canada, some of those products carried strict warnings not to give them to younger people. But with time, the age floor dropped, and by the mid-2000s, news reports and academic surveys suggest some early adopters were doing just that. (Try it for ages 11-and-up only, one CNN report warned at the time.) By 2013, according to a Wall Street Journal article, a handful of companies were marketing melatonin products specifically for kids.

Keyword: Biological Rhythms; Development of the Brain
Link ID: 29740 - Posted: 04.12.2025