Chapter 14. Biological Rhythms, Sleep, and Dreaming

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By Dino Grandoni The shrew scampered across the sand, zipping its tiny, velvety body right, left, right, left. In just a few seconds it found the prize concealed in the sandbox: a tasty mixture of earthworms, mealworms and other meat. To quickly solve the puzzle in Dina Dechmann’s lab, the shrew didn’t just need to learn where its meal was hidden. Something else astounding happened in its head. It had to regrow its own brain. “It’s a crazy animal,” said Dechmann, a behavioral ecologist at the Max Planck Institute of Animal Behavior in Germany. “We can learn a lot from the shrews.” To prepare for the depths of winter when food is scarce, many animals slow down, sleep through the cold or migrate to warmer locales. Not the common shrew. To survive the colder months, the animal eats away at its own brain, reducing the organ by as much as a fourth, only to regrow much of brain matter in the spring. The process of shrinking and expanding the brain and other organs with seasons — dubbed Dehnel’s phenomenon — allows animals to reduce calorie-consuming tissue when temperatures drop. Researchers have discovered seasonal shrinkage in the skulls of other small, high-metabolism mammals, including weasels and, most recently, moles. The shrew’s incredible shrinking brain is more than just a biological curiosity. Understanding how these animals are able to restore their brain power may help doctors treat Alzheimer’s, multiple sclerosis and other neurodegenerative diseases in humans. “In the beginning, I couldn’t quite grasp it,” said John Dirk Nieland, an associate professor of health science and technology who is now researching drugs designed to mimic shrews’ brain-altering chemistry in humans.

Keyword: Biological Rhythms; Multiple Sclerosis
Link ID: 28580 - Posted: 12.03.2022

By Dino Grandoni The shrew scampered across the sand, zipping its tiny, velvety body right, left, right, left. In just a few seconds it found the prize concealed in the sandbox: a tasty mixture of earthworms, mealworms and other meat. To quickly solve the puzzle in Dina Dechmann’s lab, the shrew didn’t just need to learn where its meal was hidden. Something else astounding happened in its head. It had to regrow its own brain. “It’s a crazy animal,” said Dechmann, a behavioral ecologist at the Max Planck Institute of Animal Behavior in Germany. “We can learn a lot from the shrews.” To prepare for the depths of winter when food is scarce, many animals slow down, sleep through the cold or migrate to warmer locales. Not the common shrew. To survive the colder months, the animal eats away at its own brain, reducing the organ by as much as a fourth, only to regrow much of brain matter in the spring. The process of shrinking and expanding the brain and other organs with seasons — dubbed Dehnel’s phenomenon — allows animals to reduce calorie-consuming tissue when temperatures drop. Researchers have discovered seasonal shrinkage in the skulls of other small, high-metabolism mammals, including weasels and, most recently, moles. The shrew’s incredible shrinking brain is more than just a biological curiosity. Understanding how these animals are able to restore their brain power may help doctors treat Alzheimer’s, multiple sclerosis and other neurodegenerative diseases in humans. “In the beginning, I couldn’t quite grasp it,” said John Dirk Nieland, an associate professor of health science and technology who is now researching drugs designed to mimic shrews’ brain-altering chemistry in humans.

Keyword: Biological Rhythms; Multiple Sclerosis
Link ID: 28579 - Posted: 12.03.2022

Max Barnhart In 2004, when physician Dr. Wilfried Mutombo began treating patients diagnosed with sleeping sickness, the available treatments were themselves horrific and sometimes deadly. "The widely available treatment then was an arsenic-based drug, and it was toxic. It could kill up to 5% of patients," he says. "I lost two of my patients. They were young, and that was a very bad experience. Sleeping sickness is an often fatal disease caused by a parasite where infected people become prone to sleeping all day and night as the disease progresses. It's endemic to 36 countries in Africa, but most cases occur in the Democratic Republic of the Congo. Now, a new oral drug has emerged that is 95% effective at curing sleeping sickness with just one dose. The results of clinical trials for this new drug, acoziborole, were published in The Lancet Infectious Diseases on Nov. 29. It has the potential to drastically change the way sleeping sickness is treated and help the World Health Organization (WHO) reach its goal of eliminating sleeping sickness by 2030. There are two kinds of sleeping sicknesses, both caused by Trypanosoma parasites. The most common form of the disease, and the one treated by this new drug, is caused by Trypanosoma brucei gambiense. Humans are the primary reservoir for the parasite, and it is spread to others by tsetse flies. WHO estimates there were roughly 300,000 cases per year in the late '90s, but the number of cases has now dropped to fewer than 1,000 cases per year. © 2022 npr

Keyword: Sleep
Link ID: 28577 - Posted: 12.03.2022

By Sandra G. Boodman The first time it happened, Erin Bousquet was a high school freshman who had been diagnosed with strep throat, a common infection in her family. After three days on an antibiotic, she wasn’t getting better, so the 14-year-old was prescribed a second drug. A day or two later, Kristen Bousquet noticed worrisome changes in her oldest child. Erin seemed “lethargic and out of it,” her mother recalled. She was irritable, her pupils looked dilated, and much of what she said made no sense. Most alarming was Erin’s newfound ability to sleep for up to 20 hours at a time. “It was quite scary,” Kristen recalled. “At first we thought she was joking.” That bizarre episode, which occurred in September 2017, has been followed by 11 more, each lasting an average of 10 days. Between episodes, Erin’s behavior is normal. For 2 1/2 years she and her parents, who live in Lincoln, Neb., consulted pediatric neurologists, a neurosurgeon, an obstetrician-gynecologist and other specialists in a largely fruitless search to identify the condition that drastically alters her personality and temporarily shuts down her life two or three times a year. The diagnosis, made in March 2020, was an enormous relief. But it has required the Bousquets to cope with continued uncertainty because so little is known about Erin’s disorder. “The hardest thing for me are the things I’ve missed out on,” said Erin, a 19-year-old sophomore at the University of Nebraska at Lincoln. They include a high school basketball championship, her 18th birthday, a family Christmas trip to Colorado and the start of her sophomore year of college. Erin slept through them all. Because her symptoms — disorientation and prolonged sleep — can be signs of a serious, even life-threatening, illness, the staff at the urgent care clinic where Erin had been treated for strep told her mother to take her to an emergency room. A test for infectious mononucleosis, a contagious virus common among adolescents and young adults that causes profound fatigue was negative and a quick neurological exam was normal. Erin was sent home.

Keyword: Sleep
Link ID: 28567 - Posted: 11.23.2022

By Christina Jewett By 2015, Philips Respironics knew its breathing devices had a problem: Foam inside the CPAP machines, which help people with sleep apnea breathe at night, was breaking off into black flecks and blowing into the mouths and noses of users. The company did nothing at the time. Years went by as complaints mounted, and the company made cursory efforts to examine the problem, according to an investigation conducted later by the Food and Drug Administration. But it was not until April of last year, the company has claimed, that it realized the flaking foam contained potentially cancer-causing particles, setting off the largest and most disruptive medical device recall in more than a decade. Nearly a year and a half after the recall that involved more than five million devices worldwide, millions of American have endured a long wait for a device. Many have been forced to find alternative methods to ensure they can breathe at night without becoming deprived of oxygen or risking a heart attack. Others have been outraged by unexpected illness, suspicious that a device meant to help them actually caused harm. The U.S. Justice Department is now negotiating the terms of a consent decree with Philips, underscoring the deep concern about what the company knew — or should have known — before millions of people received devices that many believe caused devastating illnesses. A decree would likely require the company to document the steps it would take to prevent such a failure in the future. Doug Shiffler, a retired tech executive in Utah, is one of hundreds of people suing the company. His wife began using the device in 2018, when there were no public warnings of possible problems with the machines, and developed a persistent cough. By mid-2020, Joleen Shiffler was diagnosed with an aggressive lung cancer that baffled her doctors, although a direct link between her disease and the Philips device had not been established. Ms. Shiffler, 60, died within the year. “Why weren’t we informed that there was an issue?” Mr. Shiffler asked. If they had known, “I might be standing right beside Joleen instead of mourning her loss.” © 2022 The New York Times Company

Keyword: Sleep
Link ID: 28551 - Posted: 11.16.2022

By Jackie Rocheleau For people haunted by recurring nightmares, untroubled sleep would be a dream come true. Now in a small experiment, neuroscientists have demonstrated a technique that, for some, may chase the bad dreams away. Enhancing the standard treatment for nightmare disorder with a memory-boosting technique cut down average weekly nightmares among a few dozen people from three to near zero, researchers report online October 27 in Current Biology. “The fact that they could actually make a big difference in the frequency of those nightmares is huge,” says Gina Poe, a neuroscientist at UCLA who wasn’t involved in the study. People with nightmare disorder fear the night not for the monsters under the bed, but the monsters in their dreams. Frequent, terrifying dreams disturb sleep and even affect well-being in waking life. The go-to nightmare disorder treatment is imagery rehearsal therapy, or IRT. In this treatment, patients reimagine nightmares with a positive spin, mentally rehearsing the new story line while awake. It reduces nightmares for most but fails for nearly a third of people. To boost IRT’s power, neuroscientist Sophie Schwartz of the University of Geneva and her colleagues leveraged a learning technique called targeted memory reactivation, or TMR. In this technique, a person focuses on learning something while a sound plays, and that same cue plays again during sleep. Experiencing the cue during sleep, which is important for memory storage, may reactivate and strengthen the associated memory (SN: 10/3/19). In the new study, the researchers gave 36 people with nightmare disorder training in IRT, randomly assigning half of them to rehearse their revised nightmares in silence. The other half rehearsed while a short piano chord, the TMR cue, played every 10 seconds for five minutes. © Society for Science & the Public 2000–2022.

Keyword: Sleep
Link ID: 28532 - Posted: 10.28.2022

WASHINGTON — A massive recall of millions of sleep apnea machines has stoked anger and frustration among patients, and U.S. officials are weighing unprecedented legal action to speed a replacement effort that is set to drag into next year. Sound-dampening foam in the pressurized breathing machines can break down over time, leading users to potentially inhale tiny black particles or hazardous chemicals while they sleep, manufacturer Philips warned in June 2021. Philips initially estimated it could repair or replace the units within a year. But with the recall expanding to more than 5 million devices worldwide, the Dutch company now says the effort will stretch into 2023. That's left many patients to choose between using a potentially harmful device or trying risky remedies, including removing the foam themselves, buying second-hand machines online or simply going without the therapy. The devices are called continuous positive airway pressure, or CPAP, machines. They force air through a mask to keep passageways open during sleep. Untreated sleep apnea can cause people to stop breathing hundreds of times per night, leading to dangerous drowsiness and increased heart attack risk. The problem is more common in men than women, with estimates ranging from 10% to 30% of adults affected. Most patients are better off using a recalled device because the risks of untreated sleep apnea still outweigh the potential harms of the disintegrating foam, physicians say. But doctors have been hard pressed to help patients find new machines, which generally cost between $500 and $1,000, and were already in short supply due to supply chain problems. © 2022 npr

Keyword: Sleep
Link ID: 28523 - Posted: 10.26.2022

Nicola Davis Science correspondent Playing sounds while you slumber might help to strengthen some memories while weakening others, research suggests, with experts noting the approach might one day help people living with traumatic recollections. Previous work has shown that when a sound is played as a person learns an association between two words, the memory of that word association is boosted if the same sound is played while the individual sleeps. Now researchers have found fresh evidence the approach could also be used to weaken such memories. “We can an actually induce forgetting of specific material whilst people are asleep,” said Dr Aidan Horner, co-author of the study from the University of York. Advertisement Writing in the journal Learning & Memory, Horner and colleagues report how 29 participants were shown pairs of words on a computer screen, one of which was an object word, such as bicycle, while the other was either a place word, such as office, or a person, such as David Beckham. The process was repeated for 60 different object words, and in the course of the process both possible pairings were shown, resulting in 120 associations. As the pairs flashed up, participants heard the object word being spoken out loud. The team tested the participants on a subset of the associations, presenting them with one of the words and asking them to select a paired word from a list of six options. Participants then spent a night in the team’s sleep laboratory. Once they had entered a particular sleep state – as judged by electrodes placed on their heads – they were played audio of 30 of the object words. The team tested participants on the word associations the next day. The results reveal participants’ ability to recall the first word they had learned to pair with an object word was boosted if audio of the latter was played as they slept, compared with if it was not played. However, their ability to recall the second word they learned to associate with the same object decreased relative to the audio-free scenario. © 2022 Guardian News & Media Limited

Keyword: Sleep; Learning & Memory
Link ID: 28516 - Posted: 10.19.2022

By Erin Blakemore Empathy and generosity are two traits that arguably make the world go ‘round. But a study suggests that the willingness to help collapses when people get too little — or poor — sleep. To see how sleep affects how much humans help one another, researchers conducted three experiments designed to examine the issue from the individual to the societal scale. Their results are published in PLOS Biology. In the first experiment, researchers performed functional magnetic resonance imaging scans of the brain and asked questions to 24 adults after eight hours of sleep and after a night with no sleep. When they were well rested, the participants scored well on a helping behavior test. But after sleep deprivation, 78 percent had less of a desire to help others, even when it came to friends and family. The scans showed that areas of the brain associated with social cognition — our thought processes related to other people — were less active with sleep deprivation. The second experiment tracked 136 healthy adults over four nights and asked them questions about helping the following day. The effect held for them, too, and those who reported worse sleep quality scored worse on the tests. Just one hour of extra sleep each night can lead to better eating habits To test the effects on a societal level, the researchers then looked at a database of 3 million charitable donations given between 2001 and 2016. They found that immediately following the beginning of daylight saving time — a notorious sleep disrupter — donations dropped 10 percent. The effect wasn’t found in data from Hawaii or Arizona, however; neither observe DST. Nor did the shift back to standard time have such an association with donations.

Keyword: Sleep; Emotions
Link ID: 28503 - Posted: 10.08.2022

By Deborah Balthazar It’s a frustration many parents know all too well: You’ve finally lulled your crying baby to sleep, so you put them down in their crib … and the wailing begins again. Science may have a trick for you. Carrying a crying infant for about five minutes, then sitting for at least another five to eight minutes can calm and lull the baby to sleep long enough to allow a parent to put the child down without waking them, researchers report September 13 in Current Biology. Some of those same researchers previously showed that carrying a crying baby soothes the child and calms a racing heart rate (SN: 4/18/13). For the new study, the team looked at what it takes to get that crying baby to nod off and stay asleep. The researchers put heart rate monitors on 21 crying babies, ranging in age from newborns to 7 months old. The team also took videos of the infants, monitoring their moods as their mothers carried them around a room, sat holding them and laid them in a crib. That allowed the team to observe how the babies responded to different environments, whether they were crying, fussy, alert or drowsy, heartbeat by heartbeat. “We tested the physiology behind these things that tend to be kind of common knowledge, though it’s not really well understood why they work,” says Gianluca Esposito, a developmental psychologist at the University of Trento in Italy. The babies’ heart rates slowed and they stopped crying when their mothers picked them up and carried them around for five minutes. Some infants even fell asleep. But the researchers also noticed that the babies tended to respond to the movement of the parent, whether they were in deep sleep or not. For instance, a baby’s heart rate quickened if a parent turned quickly while walking or tried to put the baby down. © Society for Science & the Public 2000–2022.

Keyword: Sleep; Development of the Brain
Link ID: 28494 - Posted: 10.01.2022

By Jim Robbins Tens of thousands of bar-tailed godwits are taking advantage of favorable winds this month and next for their annual migration from the mud flats and muskeg of southern Alaska, south across the vast expanse of the Pacific Ocean, to the beaches of New Zealand and eastern Australia. They are making their journey of more than 7,000 miles by flapping night and day, without stopping to eat, drink or rest. “The more I learn, the more amazing I find them,” said Theunis Piersma, a professor of global flyway ecology at the University of Groningen in the Netherlands and an expert in the endurance physiology of migratory birds. “They are a total evolutionary success.” The godwit’s epic flight — the longest nonstop migration of a land bird in the world — lasts from eight to 10 days and nights through pounding rain, high winds and other perils. It is so extreme, and so far beyond what researchers knew about long-distance bird migration, that it has required new investigations. In a recent paper, a group of researchers said the arduous journeys challenge “underlying assumptions of bird physiology, orientation, and behavior,” and listed 11 questions posed by such migrations. Dr. Piersma called the pursuit of answers to these questions “the new ornithology.” The extraordinary nature of what bar-tailed and other migrating birds accomplish has been revealed in the last 15 years or so with improvements to tracking technology, which has given researchers the ability to follow individual birds in real time and in a detailed way along the full length of their journey. “You know where a bird is almost to the meter, you know how high it is, you know what it’s doing, you know its wing-beat frequency,” Dr. Piersma said. “It’s opened a whole new world.” The known distance record for a godwit migration is 13,000 kilometers, or nearly 8,080 miles. © 2022 The New York Times Company

Keyword: Animal Migration; Sleep
Link ID: 28484 - Posted: 09.21.2022

By Jackie Rocheleau After experimenting on a hen, his dog, his goldfish, and himself, dentist William Morton was ready. On Oct. 16, 1846, he hurried to the Massachusetts General Hospital surgical theater for what would be the first successful public test of a general anesthetic. His concoction of sulfuric ether and oil from an orange (just for the fragrance) knocked a young man unconscious while a surgeon cut a tumor from his neck. To the onlooking students and clinicians, it was like a miracle. Some alchemical reaction between the ether and the man’s brain allowed him to slip into a state akin to light sleep, to undergo what should have been a painful surgery with little discomfort, and then to return to himself with only a hazy memory of the experience. General anesthesia redefined surgery and medicine, but over a century later it still carries significant risks. Too much sedation can lead to neurocognitive disorders and may even shorten lifespan; too little can lead to traumatic and painful wakefulness during surgery. So far, scientists have learned that, generally speaking, anesthetic drugs render people unconscious by altering how parts of the brain communicate. But they still don’t fully understand why. Although anesthesia works primarily on the brain, anesthesiologists do not regularly monitor the brain when they put patients under. And it is only in the past decade that neuroscientists interested in altered states of consciousness have begun taking advantage of anesthesia as a research tool. “It’s the central irony” of anesthesiology, says George Mashour, a University of Michigan neuroanesthesiologist, whose work entails keeping patients unconscious during neurosurgery and providing appropriate pain management. Mashour is one of a small set of clinicians and scientists trying to change that. They are increasingly bringing the tools of neuroscience into the operating room to track the brain activity of patients, and testing out anesthesia on healthy study participants. These pioneers aim to learn how to more safely anesthetize their patients, tailoring the dose to individual patients and adjusting during surgery. They also want to better understand what governs the transitions between states of consciousness and even hope to crack the code of coma. © 2022 NautilusThink Inc, All rights reserved.

Keyword: Sleep; Consciousness
Link ID: 28480 - Posted: 09.17.2022

Michael Heithaus Could you explain how fish sleep? Do they drift away on currents, or do they anchor themselves to a particular location when they sleep? – Laure and Neeraj, New York From the goldfish in your aquarium to a bass in a lake to the sharks in the sea – 35,000 species of fish are alive today, more than 3 trillion of them. All over the world, they swim in hot springs, rivers, ponds and puddles. They glide through freshwater and saltwater. They survive in the shallows and in the darkest depths of the ocean, more than five miles down. If those trillions of fish, three major types exist: bony fish, like trout and sardines; jawless fish, like the slimy hagfish; and sharks and rays, which are boneless – instead, they have skeletons made of firm yet flexible tissue called cartilage. And all of them, every last one, needs to rest. Whether you’re a human or a haddock, sleep is essential. It gives a body time to repair itself, and a brain a chance to reset and declutter. As a marine biologist, I’ve always wondered how fish can rest. After all, in any body of water, predators are all over the place, lurking around, ready to eat them. But somehow they manage, like virtually all creatures on Earth. See the mysterious spot off the coast of Mexico where sharks take a nap. How they do it Scientists are still learning about how fish sleep. What we do know: Their sleep is not like ours. © 2010–2022, The Conversation US, Inc.

Keyword: Sleep; Evolution
Link ID: 28465 - Posted: 09.07.2022

By Rebecca Sohn Distinctive bursts of sleeping-brain activity, known as sleep spindles, have long been generally associated with strengthening recently formed memories. But new research has managed to link such surges to specific acts of learning while awake. These electrical flurries, which can be observed as sharp spikes on an electroencephalogram (EEG), tend to happen in early sleep stages when brain activity is otherwise low. A study published in Current Biology shows that sleep spindles appear prominently in particular brain areas that had been active in study participants earlier, while they were awake and learning an assigned task. Stronger spindles in these areas correlated with better recall after sleep. “We were able to link, within [each] participant, exactly the brain areas used for learning to spindle activity during sleep,” says University of Oxford cognitive neuroscientist Bernhard Staresina, senior author on the study. Staresina, Marit Petzka of the University of Birmingham in England and their colleagues devised a set of tasks they called the “memory arena,” which required each participant to memorize a sequence of images appearing inside a circle. While the subjects did so, researchers measured their brain activity with an EEG, which uses electrodes placed on the head. Participants then took a two-hour nap, after which they memorized a new image set—but then had to re-create the original image sequence learned before sleeping. During naps, the researchers recorded stronger sleep spindles in the specific brain areas that had been active during the pre-sleep-memorization task, and these areas differed for each participant. This suggested that the spindle pattern was not “hardwired” in default parts of the human brain; rather it was tied to an individual's thought patterns. The researchers also observed that participants who experienced stronger sleep spindles in brain areas used during memorization did a better job re-creating the images' positions after the nap. © 2022 Scientific American

Keyword: Sleep; Learning & Memory
Link ID: 28460 - Posted: 09.03.2022

Steven Strogatz Dreams are so personal, subjective and fleeting, they might seem impossible to study directly and with scientific objectivity. But in recent decades, laboratories around the world have developed sophisticated techniques for getting into the minds of people while they are dreaming. In the process, they are learning more about why we need these strange nightly experiences and how our brains generate them. In this episode, Steven Strogatz speaks with sleep researcher Antonio Zadra of the University of Montreal about how new experimental methods have changed our understanding of dreams. Steven Strogatz (00:03): I’m Steve Strogatz, and this is The Joy of Why, a podcast from Quanta Magazine that takes you into some of the biggest unanswered questions in math and science today. (00:13) In this episode, we’re going to be talking about dreams. What are dreams exactly? What purpose do they serve? And why are they often so bizarre? We’ve all had this experience: You’re dreaming about something fantastical, some kind of crazy story with a narrative arc that didn’t actually happen, with people we don’t necessarily know, in places we may have never even been. Is this just the brain trying to make sense of random neural firing? Or is there some evolutionary reason for dreaming? Dreams are inherently hard to study. Even with all the advances in science and technology, we still haven’t really found a way to record what someone else is dreaming about. Plus, as we all know, it’s easy to forget our dreams as soon as we wake up, unless we’re really careful to write them down. But even with all these difficulties, little by little, dream researchers are making progress in figuring out how we dream and why we dream. (01:11) Joining me now to discuss all this is Dr. Antonio Zadra, a professor at the University of Montreal and a researcher at the Center for Advanced Research in Sleep Medicine. His specialties include the study of nightmares, recurrent dreams and lucid dreaming. He’s also the coauthor of the recent book When Brains Dream, exploring the science and mystery of sleep. Tony, thank you so much for joining us today. Strogatz (01:39): I’m very excited to talk to you about this. So let’s start with thinking about the science of dreams as you and your colleagues see it today. Why are dreams so hard to study? All Rights Reserved © 2022

Keyword: Sleep; Evolution
Link ID: 28454 - Posted: 08.27.2022

Yuta Senzai Massimo Scanziani Does rapid eye movement during sleep reveal where you’re looking at in the scenery of dreams, or are they simply the result of random jerks of our eye muscles? Since the discovery of REM sleep in the early 1950s, the significance of these rapid eye movements has intrigued and fascinated scores of scientists, psychologists and philosophers. REM sleep, as the name implies, is a period of sleep when your eyes move under your closed eyelids. It’s also the period when you experience vivid dreams. We are researchers who study how the brain processes sensory information during wakefulness and sleep. In our recently published study, we found that the eye movements you make while you sleep may reflect where you’re looking in your dreams. Past studies have attempted to address this question by monitoring the eye movements of people as they slept and waking them up to ask what they were dreaming. The goal was to find a possible connection between the content of a dream just before waking up (say, a car coming in from the left) and the direction the eyes moved at that moment. Unfortunately, these studies have led to contradictory results. It could be that some participants inaccurately reported dreams, and it’s technically difficult to match a given eye movement to a specific moment in a self-reported dream. We decided to bypass the problem of dream self-reporting. Instead, we used a more objective way to measure dreams: the electrical activity of a sleeping mouse brain. Mice, like humans and many other animals, also experience REM sleep. Additionally, they have a sort of internal compass in their brains that gives them a sense of head direction. When the mouse is awake and running around, the electrical activity of this internal compass precisely reports its head direction, or “heading,” as it moves in its environment. © 2010–2022, The Conversation US, Inc.

Keyword: Sleep; Vision
Link ID: 28453 - Posted: 08.27.2022

By Sujata Gupta Lack of sleep has been linked to heart disease, poor mood and loneliness (SN: 11/15/16). Being tired could also make us less generous, researchers report August 23 in PLOS Biology. The hour of sleep lost in the switch over to Daylight Savings Time every spring appears to reduce people’s tendency to help others, the researchers found in one of three experiments testing the link between sleep loss and generosity. Specifically, they showed that average donations to one U.S.-based nonprofit organization dropped by around 10 percent in the workweek after the time switch compared with four weeks before and after the change. In Arizona and Hawaii, states that do not observe Daylight Savings Time, donations remained unchanged. With over half of the people living in parts of the developed world reporting that they rarely get enough sleep during the workweek, the finding has implications beyond the week we spring forward, the researchers say. “Lack of sleep shapes the social experiences we have [and] the kinds of societies we live in,” says neuroscientist Eti Ben Simon of the University of California, Berkeley. To test the link between sleep loss and generosity, Ben Simon and her team first brought 23 young adults into the lab for two nights. The participants slept through one night and stayed awake for another night. In the mornings, participants completed a standardized altruism questionnaire rating their likelihood of helping strangers or acquaintances in various scenarios. For instance, participants rated on a scale from 1 to 5, with 1 for least likely to help and 5 for most likely, whether they would give up their seat on a bus to a stranger or offer a ride to a coworker in need. Participants never read the same scenario more than once. Roughly 80 percent of participants showed less likelihood of helping others when sleep-deprived than when rested. © Society for Science & the Public 2000–2022.

Keyword: Sleep; Emotions
Link ID: 28444 - Posted: 08.24.2022

By Carolyn Wilke Sign up for Science Times Get stories that capture the wonders of nature, the cosmos and the human body. Get it sent to your inbox. By day, jumping spiders hunt their prey, stalking and pouncing like cats. When the lights go down, these pea-sized predators hang out — and maybe their minds spin dreams. As they twitch their legs and move their eyes, Evarcha arcuata, a species of jumping spiders, show something reminiscent of rapid eye movement, or R.E.M., sleep, researchers report Monday in the Proceedings of the National Academy of Sciences. R.E.M. is the phase of sleep during which most human dreaming occurs. The study suggests that R.E.M. sleep may be more common than realized across animals, which may help untangle the mysteries of its purpose and evolution. To “look at R.E.M. sleep in something as distantly related to us as spiders is just utterly fascinating,” said Lauren Sumner-Rooney, a sensory biologist at the Leibniz Institute for Biodiversity and Evolution Research who wasn’t part of the new study. Daniela Roessler, a behavioral ecologist at the University of Konstanz in Germany and one of the study’s authors, was surprised when she noticed that jumping spiders sometimes dangle upside down during the night. Dr. Roessler started filming the resting arachnids and noticed other odd behaviors. “All of a sudden, they would make these crazy movements with the legs and start twitching. And it just reminded me immediately of a sleeping — not to say dreaming — cat or dog,” said Dr. Roessler. Such jerky movements in limbs are a marker of R.E.M. sleep, a state in which most of the body’s muscles go slack and the brain’s electrical activity mimics being awake. And then there’s the darting eyes, from which R.E.M. gets its name. But that’s tricky to spot it in animals with eyes that do not move, including spiders. However, part of a jumping spider’s eye does move. The acrobatic arachnids have eight eyes in total, and behind the lenses of their two biggest eyes are light-catching retinas that move to scan the environment. The arthropods’ exterior typically obscures these banana-shaped tubes, except when the spiders are babies and have translucent exoskeletons. So Dr. Roessler’s team looked for flitting retinas during rest in spiderlings younger than 10 days old. “It’s really clever,” said Paul Shaw, a neuroscientist at the Washington University School of Medicine. The researchers chose the right animal for this question, he added. © 2022 The New York Times Company

Keyword: Sleep; Evolution
Link ID: 28431 - Posted: 08.11.2022

Mo Costandi We spend approximately one-third of our lives sleeping, but why sleep is important is a big unanswered question, one which science has only begun to answer recently. We now know, for example, that the brain cleans itself while we sleep, and that long-term memories form during the rapid eye movement (REM) stage of sleep. Your brain is highly active during sleep Sleep can be defined as a temporary state of unconsciousness, during which our responses to the outside world are reduced. Yet, we also know that the brain is active during sleep, and there is growing evidence that it remains highly responsive: For instance, your sleeping brain will respond to your name, categorize words and then prepare appropriate actions, and even learn new information. Now, a new study by researchers at UCLA and Tel Aviv University shows that the human brain remains highly responsive to sound during sleep, but it does not receive feedback from higher order areas — sort of like an orchestra with “the conductor missing.” The findings could point to a better understanding of the extent to which the brain processes information in disorders of consciousness such as coma and vegetative states, and to the neural mechanisms of conscious awareness. The missing conductor Hanna Hayat and her colleagues had the rare opportunity to record the activity of cells directly from the brains of 13 patients with drug-resistant epilepsy, who were being evaluated for brain surgery and gave written consent to participate in the study during the evaluation. The researchers implanted depth electrodes in multiple regions of the patients’ brains, primarily to identify the source of their seizures, so that the abnormal tissue could be surgically removed. Over the course of eight overnight sessions and six daytime naps, they played various sounds — including words, sentences and music — to the patients through bedside loudspeakers. They also used standard electroencephalogram (EEG) to monitor the patients’ sleep stages and recorded their sleep behavior with video. © Copyright 2007-2022 & BIG THINK,

Keyword: Sleep
Link ID: 28416 - Posted: 08.03.2022

By Linda Searing Routinely getting a good night’s sleep has been added to the American Heart Association’s list of key components of cardiovascular health, lengthening the list to eight factors the association believes can lead to a longer, higher-quality life without heart disease. Heart disease is the leading cause of death in the United States and has been for the past century, according to the Centers for Disease Control and Prevention. Since 2010, the AHA had focused on seven points: maintaining a healthy weight, not smoking, being physically active, eating a healthy diet, and keeping blood pressure, cholesterol and blood sugar at acceptable levels. Now, however, as indicated in its report published in the journal Circulation, the AHA believes that healthy sleep also should be taken into account. The group’s suggested goal is seven to nine hours of sleep daily for adults, and more for children (eight to 10 hours for 13- to 18-year-olds, nine to 12 hours for 6- to 12-year-olds and 10 to 16 hours for children 5 and younger). Sleep has long been considered vital to good health, both physically and psychologically. Sleep gives the body a needed break to heal and repair itself, setting people up to function normally when they awaken. But a lack of sleep (or poor-quality sleep) puts a person at higher risk for such conditions as diabetes, obesity, high blood pressure and more. © 1996-2022 The Washington Post

Keyword: Sleep
Link ID: 28395 - Posted: 07.14.2022