Chapter 14. Biological Rhythms, Sleep, and Dreaming

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By Nicholas Bakalar If you are a morning person, you may be at reduced risk for major depression, a new study suggests. Several studies of the body’s circadian sleep-wake cycle have shown that being an early bird is associated with a lower risk for depression. But those studies were observational so could not prove cause and effect. For example, people who are early birds may have other health or lifestyle behaviors that reduce their risk for depression — they may have a healthier diet, for example, exercise more, or have fewer health conditions, such as chronic pain, that are associated with depression. All these factors, and many others, could explain the decreased risk for depression, and not the fact of being an early bird. Moreover, depression itself causes sleep disturbances, so it could be that depression is a cause of being a night owl, rather than the other way around. The new study, however, offers more compelling evidence that going to bed early and waking early may, in itself, provide protection against depression, independent of other factors. The study, published in JAMA Psychiatry, uses a research method called Mendelian randomization that helps pinpoint the cause of what may be a cause-and-effect relationship. With Mendelian randomization, researchers can compare large groups of people based on genetic variants that are independent of other health or behavioral characteristics — in this case, the tendency to being a night owl or a morning person, inherited traits that are randomly allocated during our development in the womb. More than 340 genetic variants associated with circadian sleep rhythm have been identified, and the researchers can compare large groups of people with the genetic variants for being a morning person with groups that lack them. Nature has, in essence, set up the randomized experiment for them. © 2021 The New York Times Company

Keyword: Biological Rhythms; Depression
Link ID: 27868 - Posted: 06.23.2021

By Anahad O'Connor According to recent studies, the number of people complaining of insomnia skyrocketed during the pandemic, rising from 20 percent of adults last summer to nearly 60 percent in March. If you’re one of those people who’s been plagued by poor sleep, the Well desk is here to help. Recently, we asked our readers to tell us two things: What’s keeping you from getting a good night’s rest? And what are the most pressing questions you would ask a sleep expert? More than 1,200 of you responded. You asked about insomnia, supplements, middle-of-the-night awakenings, snoring bed mates and more. So we collected your most popular questions, brought them to the world’s top sleep experts and shared their answers below. Sometimes I am physically tired but can’t fall asleep. How is that possible? This is what’s known as the tired but wired syndrome. Usually, it’s driven by stress and anxiety. Even if you’re exhausted, a racing mind can activate the “fight or flight” branch of your nervous system, making you alert and unable to fall asleep. “For us to fall asleep and stay asleep, we need to go in the opposite nervous system direction,” said Matthew Walker, a professor of neuroscience and psychology at the University of California, Berkeley, and the author of the best-selling book “Why We Sleep.” “We need to shift over to the calming branch of the nervous system called the parasympathetic nervous system.” © 2021 The New York Times Company

Keyword: Sleep
Link ID: 27847 - Posted: 06.11.2021

Nicholas Bakalar Many people wear a CPAP machine at night to treat the interrupted breathing of obstructive sleep apnea, a condition that affects an estimated 22 million Americans. But CPAP machines can be noisy, cumbersome and uncomfortable, and many people stop using the devices altogether, which can have dire long-term consequences. Mouth guards may be a more comfortable and easy-to-use alternative for many people with obstructive sleep apnea, according to a new report. The study, published in Laryngoscope, looked at 347 people with sleep apnea who were fitted with a mouth guard by an otolaryngologist. Two-thirds of patients reported they were comfortable wearing the devices, and the devices appeared to be effective in helping to relieve the disordered breathing of obstructive sleep apnea. The lead author of the study, Dr. Guillaume Buiret, head of otolaryngology at Valence Hospital in Valence, France, said that if he had sleep apnea, he would choose an oral appliance first. “It’s easy to tolerate, effective and it costs a lot less than CPAP,” he said. “Thirty to 40 percent of our patients can’t use CPAP, and these patients almost always find the dental appliance helpful. I would recommend it as a first-line treatment” Loud snoring may be the most obvious consequence of sleep apnea, but the condition, if left untreated, can lead to a broad range of complications, including high blood pressure, heart disease, liver dysfunction and Type 2 diabetes. © 2021 The New York Times Company

Keyword: Sleep
Link ID: 27838 - Posted: 06.02.2021

Abby Olena Leptin is a hormone released by fat cells in adult organisms, and researchers have largely focused on how it controls appetite. In a study published May 18 in Science Signaling, the authors show that leptin promotes synapse formation, or synaptogenesis, in developing rodent neurons in culture. “This paper does a really wonderful job [breaking] down the mechanisms” of leptin signaling, and the authors look at changes in synaptic function, not just at the protein level, but also on a physiological level, says Laura Cocas, a neuroscientist at Santa Clara University who was not involved in the study. “Because all of the work on the paper is done in vitro, they can do very careful analysis . . . to break down each step in the signaling pathway.” When Washington State University neuroscientist Gary Wayman and his group started working on leptin about 10 years ago, most of the research had examined the hormone’s function in regulating satiety. But “we and others knew that leptin surged during a critical period of neuronal—and in particular synaptic—development in the brain,” he says. In people, this surge happens during the third trimester of fetal development and, in rodents, over the first few weeks of life. “This surge in leptin is independent of the amount of adipose tissue that’s present. And it does not control feeding during this period because feeding circuits have not developed, so we really wanted to understand what the developmental role was.” Wayman and colleagues focused on the hippocampus because, despite being one of the best-characterized regions in the brain, there wasn’t a lot of information out there about what the leptin receptors present were doing—particularly during development. Multiple groups had also shown that leptin injected in this brain region can improve cognition and act as an antidepressant. © 1986–2021 The Scientist.

Keyword: Obesity; Learning & Memory
Link ID: 27837 - Posted: 05.29.2021

Veronique Greenwood The hydra is a simple creature. Less than half an inch long, its tubular body has a foot at one end and a mouth at the other. The foot clings to a surface underwater — a plant or a rock, perhaps — and the mouth, ringed with tentacles, ensnares passing water fleas. It does not have a brain, or even much of a nervous system. And yet, new research shows, it sleeps. Studies by a team in South Korea and Japan showed that the hydra periodically drops into a rest state that meets the essential criteria for sleep. On the face of it, that might seem improbable. For more than a century, researchers who study sleep have looked for its purpose and structure in the brain. They have explored sleep’s connections to memory and learning. They have numbered the neural circuits that push us down into oblivious slumber and pull us back out of it. They have recorded the telltale changes in brain waves that mark our passage through different stages of sleep and tried to understand what drives them. Mountains of research and people’s daily experience attest to human sleep’s connection to the brain. But a counterpoint to this brain-centric view of sleep has emerged. Researchers have noticed that molecules produced by muscles and some other tissues outside the nervous system can regulate sleep. Sleep affects metabolism pervasively in the body, suggesting that its influence is not exclusively neurological. And a body of work that’s been growing quietly but consistently for decades has shown that simple organisms with less and less brain spend significant time doing something that looks a lot like sleep. Sometimes their behavior has been pigeonholed as only “sleeplike,” but as more details are uncovered, it has become less and less clear why that distinction is necessary. All Rights Reserved © 2021

Keyword: Sleep; Evolution
Link ID: 27825 - Posted: 05.19.2021

By Sofia Moutinho There’s no 9-to-5 for female northern elephant seals. After the winter breeding season, the animals spend more than 19 hours—and up to 24 hours—per day hunting in the northern Pacific Ocean, killing up to 2000 small fish daily to survive, according to a new study of these elusive animals. The work, made possible by cameras and devices attached to the seals’ heads, could also help scientists monitor other deep-ocean life. “This study is fascinating,” says Jeremy Goldbogen, a marine biologist at Stanford University who was not part of the research. “The advanced technology provides unprecedented levels of detail on where and when the elephant seals forage in a deep, dark ocean.” Northern elephant seals (Mirounga angustirostris) are mysterious animals. They appear onshore, on some Pacific Coast beaches, only twice a year: in late December or early January to mate or give birth, and about 2 months later to shed their fur. They spend the rest of their time, almost 10 months, fishing. Males, which can weigh up to 2 tons—about the weight of a small truck—hunt big fish close to the coast. Females, which are only about one-third of the size, hunt smaller fish in a deep-sea region known as the twilight zone. To get food from the zone, which reaches depths of 1500 meters, the females must hold their breath for up to 1.5 hours. “The physiological challenges that these animals face to meet their daily energetic demand is an extraordinary feat,” Goldbogen says. To find out how the females survive on the small fish—some of which are just 2 centimeters long—Japanese and U.S. researchers attached infrared video cameras with depth sensors to the heads of 48 female elephant seals. They also attached GPS trackers and a special device that could count every time a seal opened its mouth. (The researchers called their device the Kami Kami Logger, after the Japanese sound for biting, similar to the English “chomp chomp.”) © 2021 American Association for the Advancement of Science

Keyword: Sleep
Link ID: 27819 - Posted: 05.15.2021

Linda Geddes It’s a common enough scenario: you walk into your local supermarket to buy some milk, but by the time you get to the till, the milk bottle has turned into a talking fish. Then you remember you’ve got your GCSE maths exam in the morning, but you haven’t attended a maths lesson for nearly three decades. Dreams can be bafflingly bizarre, but according to a new theory of why we dream, that’s the whole point. By injecting some random weirdness into our humdrum existence, dreams leave us better equipped to cope with the unexpected. The question of why we dream has long divided scientists. Dreams’ subjective nature, and the lack of any means of recording them, makes it fiendishly difficult to prove why they occur, or even how they differ between individuals. “While various hypotheses have been put forward, many of these are contradicted by the sparse, hallucinatory, and narrative nature of dreams, a nature that seems to lack any particular function,” said Erik Hoel, a research assistant professor of neuroscience at Tufts University in Massachusetts, US. Inspired by recent insights into how machine “neural networks” learn, Hoel has proposed an alternative theory: the overfitted brain hypothesis. © 2021 Guardian News & Media Limited

Keyword: Sleep
Link ID: 27818 - Posted: 05.15.2021

Michael Marshall In her laboratory in Barcelona, Spain, Miki Ebisuya has built a clock without cogs, springs or numbers. This clock doesn’t tick. It is made of genes and proteins, and it keeps time in a layer of cells that Ebisuya’s team has grown in its lab. This biological clock is tiny, but it could help to explain some of the most conspicuous differences between animal species. Animal cells bustle with activity, and the pace varies between species. In all observed instances, mouse cells run faster than human cells, which tick faster than whale cells. These differences affect how big an animal gets, how its parts are arranged and perhaps even how long it will live. But biologists have long wondered what cellular timekeepers control these speeds, and why they vary. A wave of research is starting to yield answers for one of the many clocks that control the workings of cells. There is a clock in early embryos that beats out a regular rhythm by activating and deactivating genes. This ‘segmentation clock’ creates repeating body segments such as the vertebrae in our spines. This is the timepiece that Ebisuya has made in her lab. “I’m interested in biological time,” says Ebisuya, a developmental biologist at the European Molecular Biology Laboratory Barcelona. “But lifespan or gestation period, they are too long for me to study.” The swift speed of the segmentation clock makes it an ideal model system, she says. © 2021 Springer Nature Limited

Keyword: Development of the Brain; Evolution
Link ID: 27790 - Posted: 04.28.2021

The government of New Brunswick says there are now 47 cases of a mysterious neurological disease, for which experts are still trying to figure out a source. As of last Thursday, there have been 37 confirmed and 10 suspected cases of "a neurological syndrome of unknown cause," Bruce Macfarlane, spokesperson for the Department of Health, said in an email Monday. That brings the number of cases up from 44. The province last reported a new case in early April. There have been six deaths caused by the disease, with no new deaths reported Monday. Macfarlane said the province is collaborating with local and national subject matter experts and health-care providers to investigate the individuals showing signs and symptoms of the syndrome. "At this time, the investigation is active and ongoing to determine if there are similarities among the reported cases that can identify potential causes for this syndrome, and to help identify possible strategies for prevention. "The investigation team is exploring all potential causes including food, environmental and animal exposures." Macfarlane said most of the cases are in people who were living in areas around Moncton and on the Acadian Peninsula. "However, it is unknown at this stage of our investigation whether geographic area is linked to the neurological condition and related symptoms" he said. The disease cluster was first reported on in March, when Radio-Canada obtained a memo from Public Health to medical professionals. ©2021 CBC/Radio-Canada.

Keyword: Alzheimers; Neurotoxins
Link ID: 27788 - Posted: 04.28.2021

By Pam Belluck Could getting too little sleep increase your chances of developing dementia? For years, researchers have pondered this and other questions about how sleep relates to cognitive decline. Answers have been elusive because it is hard to know if insufficient sleep is a symptom of the brain changes that underlie dementia — or if it can actually help cause those changes. Now, a large new study reports some of the most persuasive findings yet to suggest that people who don’t get enough sleep in their 50s and 60s may be more likely to develop dementia when they are older. The research, published Tuesday in the journal Nature Communications, has limitations but also several strengths. It followed nearly 8,000 people in Britain for about 25 years, beginning when they were 50 years old. It found that those who consistently reported sleeping six hours or less on an average weeknight were about 30 percent more likely than people who regularly got seven hours sleep (defined as “normal” sleep in the study) to be diagnosed with dementia nearly three decades later. “It would be really unlikely that almost three decades earlier, this sleep was a symptom of dementia, so it’s a great study in providing strong evidence that sleep is really a risk factor,” said Dr. Kristine Yaffe, a professor of neurology and psychiatry at the University of California, San Francisco, who was not involved in the study. Pre-dementia brain changes like accumulations of proteins associated with Alzheimer’s are known to begin about 15 to 20 years before people exhibit memory and thinking problems, so sleep patterns within that time frame could be considered an emerging effect of the disease. That has posed a “chicken or egg question of which comes first, the sleep problem or the pathology,” said Dr. Erik Musiek, a neurologist and co-director of the Center on Biological Rhythms and Sleep at Washington University in St. Louis, who was not involved in the new research. © 2021 The New York Times Company

Keyword: Sleep; Alzheimers
Link ID: 27786 - Posted: 04.24.2021

By Laura Sanders Octopuses cycle through two stages of slumber, a new study reports. First comes quiet sleep, and then a shift to a twitchy, active sleep in which vibrant colors flash across the animals’ skin. These details, gleaned from four snoozing cephalopods in a lab in a Brazil, may provide clues to a big scientific mystery: Why do animals sleep? Sleep is so important that every animal seems to have a version of it, says Philippe Mourrain, a neurobiologist at Stanford University who recently described the sleep stages of fish (SN: 7/10/19). Scientists have also catalogued sleep in reptiles, birds, amphibians, bees, mammals and jellyfish, to name a few. “So far, we have not found a single species that does not sleep,” says Mourrain, who was not involved in the new study. Cephalopod neuroscientist and diver Sylvia Medeiros caught four wild octopuses, Octopus insularis, and brought them temporarily into a lab at the Brain Institute of the Federal University of Rio Grande do Norte in Natal, Brazil. After tucking the animals away in a quiet area, she began to carefully record their behavior during the day, when octopuses are more likely to rest. Two distinct states emerged, she and her colleagues report March 25 in iScience. In the first, called quiet sleep, the octopuses are pale and motionless with the pupils of their eyes narrowed to slits. Active sleep comes next. Eyes dart around, suckers contract, muscles twitch, skin textures change and, most dramatically, bright colors race across octopuses’ bodies. This wild sleep is rhythmic, happening every half an hour or so, and brief; it’s over after about 40 seconds. Active sleep is also rare; the octopuses spent less than 1 percent of their days in active sleep, the researchers found. © Society for Science & the Public 2000–2021.

Keyword: Sleep; Evolution
Link ID: 27749 - Posted: 03.27.2021

By Penelope Green In 1999, Rosalind D. Cartwright, a renowned sleep researcher, testified for the defense in the murder trial of a man who arose from his bed early one night, gathered up tools to fix his pool’s filter pump, stabbed his beloved wife to death, rolled her into the pool and went back to bed. When he was awakened by the police, he said he had no memory of his actions. His lawyers argued that the man, who had no motive to kill his wife, had been sleepwalking and was therefore in an unconscious state and not responsible for his behavior. Dr. Cartwright, who had successfully served as a witness for the defense in a similar case a decade earlier (working pro bono in both trials), agreed. The jury did not, and the man was sentenced to life in prison. As Dr. Cartwright was leaving the courtroom, however, a bailiff asked for her business card. Abashedly, he told her, “I beat people up in my sleep.” Nicknamed the Queen of Dreams by her peers, Dr. Cartwright studied the role of dreaming in divorce-induced depression, worked with sleep apnea patients and their frustrated spouses, and helped open one of the first sleep disorder clinics. She died at 98 on Jan. 15 at her home in Chicago. Her daughter, Carolyn Cartwright, said the cause was a heart attack. The earlier sleepwalking murder case that hinged on Dr. Cartwright’s testimony was a notorious one, even inspiring a television movie, “The Sleepwalker Killing”: In 1987 a young Canadian man murdered his mother-in-law and brutally attacked his father-in-law after driving from his home to theirs in his pajamas. Like the pool man, he had no motive to kill them. © 2021 The New York Times Company

Keyword: Sleep
Link ID: 27733 - Posted: 03.17.2021

By Sofia Moutinho In the movie Inception, Leonardo DiCaprio enters into other people’s dreams to interact with them and steal secrets from their subconscious. Now, it seems this science fiction plot is one baby step closer to reality. For the first time, researchers have had “conversations” involving novel questions and math problems with lucid dreamers—people who are aware that they are dreaming. The findings, from four labs and 36 participants, suggest people can receive and process complex external information while sleeping. “This work challenges the foundational definitions of sleep,” says cognitive neuroscientist Benjamin Baird of the University of Wisconsin, Madison, who studies sleep and dreams but was not part of the study. Traditionally, he says, sleep has been defined as a state in which the brain is disconnected and unaware of the outside world. Lucid dreaming got one of its first mentions in the writings of Greek philosopher Aristotle in the fourth century B.C.E., and scientists have observed it since the 1970s in experiments about the rapid eye movement (REM) phase of sleep, when most dreaming occurs. One in every two people has had at least one lucid dream, about 10% of people experience them once a month or more. Although rare, this ability to recognize you are in a dream—and even control some aspects of it—can be enhanced with training. A few studies have tried to communicate with lucid dreamers using stimuli such as lights, shocks, and sounds to “enter” people’s dreams. But these recorded only minimal responses from the sleepers and did not involve complex transmission of information. © 2021 American Association for the Advancement of Science.

Keyword: Sleep; Attention
Link ID: 27700 - Posted: 02.19.2021

By Diana Kwon Dreams are full of possibilities; by drifting into the world beyond our waking realities, we can visit magical lands, travel through time and interact with long-lost family and friends. The notion of communicating in real time with someone outside of our dreamscapes, however, sounds like science fiction. A new study demonstrates that, to some extent, this seeming fantasy can be made real. Scientists already knew that one-way contact is attainable. Previous studies have demonstrated that people can process external cues, such as sounds and smells, while asleep. There is also evidence that people are able to send messages in the other direction: Lucid dreamers—those who can become aware they are in a dream—can be trained to signal, using eye movements, that they are in the midst of a dream. Two-way communication, however, is more complex. It requires a person who is asleep to actually understand what they hear from the outside and think about it logically enough to generate an answer, explains Ken Paller, a cognitive neuroscientist at Northwestern University. “We believed that it was going to be possible—but until we actually demonstrated it, we weren’t sure.” For this study, Paller and his colleagues recruited volunteers who said they remembered at least one dream per week and provided them with guidance on how to lucid dream. They were also trained to respond to simple math problems by moving their eyes back and forth—for example, the correct answer to “eight minus six,” would be moving your eyes to the left and right twice. While the participants slept, electrodes attached to their faces picked up their eye movements and electroencephalography (EEG)—a method of monitoring brain activity—kept track of what stage of sleep they were in. © 2021 Scientific American

Keyword: Sleep; Attention
Link ID: 27699 - Posted: 02.19.2021

By Valeriya Safronova Jennifer Lopez is wearing them, Kylie Jenner and Rashida Jones are promoting them, and Drew Barrymore is selling them. Blue-light glasses are shaping up to be the accessory of our prolonged screen-mediated moment. But do we need them? Blue-light glasses are fitted with lenses that filter out certain light waves that are emitted by the sun and, to a lesser extent, by digital devices like phones, laptops and tablets. Blue light is not inherently bad; it boosts attention and wakefulness during the day. But it suppresses the natural production of melatonin at night. By limiting exposure to blue light by as little as 20 percent, companies say, a customer could sleep better, experience less eye strain and prevent potential retinal damage. Scientists, however, are not convinced that the glasses are a worthy investment. “Whichever aspect you look at, it’s very hard to justify spending the extra money,” said Dr. John Lawrenson, a professor of clinical visual science at City, University of London. (Prices vary but start at around $20.) After reviewing several studies that tested the effectiveness of blue-light-blocking lenses, he and his colleagues concluded that the glasses are not necessary. Digital eye strain is real, but it’s impossible to say with certainty that the culprit is blue light. “No one has established an independent causal association between blue light coming from the computer and visual symptoms,” Dr. Lawrenson said. He recommended going to an eye doctor for a checkup instead of rushing to buy nonprescription glasses. Regardless, the blue-light category is booming. A quick Google search pulls up several brands that almost exclusively sell “computer glasses” (like Felix Gray, which raised more than $1.7 million in funding in 2020, bringing its total funding to $7.8 million as of September, according to PitchBook), as well as prescription-eyewear companies like Zenni (which sold two million pairs of its Blokz lenses in 2020, according to the company) and Jins (which noted an uptick in online orders last year). If you’ve shopped at Warby Parker recently, you were probably asked if you’d like a blue-light filter added to your lenses. © 2021 The New York Times Company

Keyword: Sleep; Vision
Link ID: 27698 - Posted: 02.19.2021

Elizabeth Landau At a sleep research symposium in January 2020, Janna Lendner presented findings that hint at a way to look at people’s brain activity for signs of the boundary between wakefulness and unconsciousness. For patients who are comatose or under anesthesia, it can be all-important that physicians make that distinction correctly. Doing so is trickier than it might sound, however, because when someone is in the dreaming state of rapid-eye movement (REM) sleep, their brain produces the same familiar, smoothly oscillating brain waves as when they are awake. Lendner argued, though, that the answer isn’t in the regular brain waves, but rather in an aspect of neural activity that scientists might normally ignore: the erratic background noise. Some researchers seemed incredulous. “They said, ‘So, you’re telling me that there’s, like, information in the noise?’” said Lendner, an anesthesiology resident at the University Medical Center in Tübingen, Germany, who recently completed a postdoc at the University of California, Berkeley. “I said, ‘Yes. Someone’s noise is another one’s signal.’” Lendner is one of a growing number of neuroscientists energized by the idea that noise in the brain’s electrical activity could hold new clues to its inner workings. What was once seen as the neurological equivalent of annoying television static may have profound implications for how scientists study the brain. All Rights Reserved © 2021

Keyword: Sleep; Attention
Link ID: 27684 - Posted: 02.13.2021

Allyson Chiu Sleep and circadian rhythms have long been associated with the powerful effects of the sun cycle. But in recent years, a growing number of studies have suggested that another familiar celestial body might also be impacting your ability to get a restful night’s sleep: the moon. A paper published this week in the journal Science Advances found that people tend to have a harder time sleeping in the days leading up to a full moon. Researchers reported that sleep patterns among the study’s 98 participants appeared to fluctuate over the course of the 29½ -day lunar cycle, with the latest bedtimes and least amount of rest occurring on nights three to five days before the moon reaches its brightest phase. They found a similar pattern in sleep data from another group of more than 460 people. Ahead of the full moon, it took people, on average, 30 minutes longer to fall asleep and they slept for 50 minutes less, said Leandro Casiraghi, the study’s lead author and a postdoctoral researcher in the Department of Biology at the University of Washington. “What we did is we came up with a set of data that shockingly proves that this is real, that there’s an actual effect of the moon on our sleep,” Casiraghi said. Previous studies examining the moon’s effect on sleep have produced contradictory results. Some research has found minimal or no association between the lunar cycle and sleep, while other studies have demonstrated correlations in controlled settings. The findings of the Jan. 27 paper support existing observations that there is a link, Casiraghi said. But, he noted that the work he and his fellow scientists did is distinct from past research by a critical difference in methodology. © 1996-2021 The Washington Post

Keyword: Sleep
Link ID: 27668 - Posted: 01.30.2021

David Eagleman When he was two years old, Ben stopped seeing out of his left eye. His mother took him to the doctor and soon discovered he had retinal cancer in both eyes. After chemotherapy and radiation failed, surgeons removed both his eyes. For Ben, vision was gone forever. But by the time he was seven years old, he had devised a technique for decoding the world around him: he clicked with his mouth and listened for the returning echoes. This method enabled Ben to determine the locations of open doorways, people, parked cars, garbage cans, and so on. He was echolocating: bouncing his sound waves off objects in the environment and catching the reflections to build a mental model of his surroundings. Echolocation may sound like an improbable feat for a human, but thousands of blind people have perfected this skill, just like Ben did. The phenomenon has been written about since at least the 1940s, when the word “echolocation” was first coined in a Science article titled “Echolocation by Blind Men, Bats, and Radar.” How could blindness give rise to the stunning ability to understand the surroundings with one’s ears? The answer lies in a gift bestowed on the brain by evolution: tremendous adaptability. Whenever we learn something new, pick up a new skill, or modify our habits, the physical structure of our brain changes. Neurons, the cells responsible for rapidly processing information in the brain, are interconnected by the thousands—but like friendships in a community, the connections between them constantly change: strengthening, weakening, and finding new partners. The field of neuroscience calls this phenomenon “brain plasticity,” referring to the ability of the brain, like plastic, to assume new shapes and hold them. More recent discoveries in neuroscience suggest that the brain’s brand of flexibility is far more nuanced than holding onto a shape, though. To capture this, we refer to the brain’s plasticity as “livewiring” to spotlight how this vast system of 86 billion neurons and 0.2 quadrillion connections rewires itself every moment of your life.

Keyword: Sleep
Link ID: 27638 - Posted: 12.31.2020

Jon Hamilton During deep sleep, the brain appears to wash away waste products that increase the risk for Alzheimer's disease. A host of new research studies suggest that this stage of sleep — when dreams are rare and the brain follows a slow, steady beat – can help reduce levels of beta-amyloid and tau, two hallmarks of the disease. "There is something about this deep sleep that is helping protect you," says Matthew Walker, a professor of neuroscience and psychology at the University of California, Berkeley. The research comes after decades of observations linking poor sleep to long-term problems with memory and thinking, Walker says. "We are now learning that there is a significant relationship between sleep and dementia, particularly Alzheimer's disease." The strongest evidence involves deep sleep, he says. That's when body temperature drops and the brain begins to produce slow, rhythmic electrical waves. So Walker and a team of scientists set out to answer a question: "Can I look into your future and can I accurately estimate how much beta-amyloid you're going to accumulate over the next two years, the next four years, the next six years, simply on the basis of your sleep tonight?" To find out, Walker's team studied 32 people in their 70s who had taken part in a sleep study that looked for the slow electrical waves that signal deep sleep. None of the participants had memory problems. the brain cells of people with Alzheimer's. © 2020 npr

Keyword: Sleep; Alzheimers
Link ID: 27585 - Posted: 11.18.2020

By Catherine Zuckerman It’s 3 a.m. and you’ve been struggling for hours to fall asleep. Morning draws nearer and your anxiety about being exhausted the next day intensifies — yet again. If this sounds familiar, you’re not alone. Among the many disruptions of 2020, insomnia may rank high on the list. Data on how the pandemic has affected sleep is limited because biomedical research can take years to shake out and most studies to date have been small. But evidence from China and Europe suggests that prolonged confinement is altering sleep in adults as well as children. Doctors in the United States are seeing it too. “I think Covid and the election have affected sleep and could be considered a kind of trauma,” said Nancy Foldvary-Schaefer, director of the Cleveland Clinic Sleep Disorders Center. “A lot of people that I talk to — patients and non-patients and colleagues and family — have more anxiety generally now probably because of these two stressors, and high anxiety is clearly associated with insomnia.” Whether you’re suddenly tossing and turning at bedtime or waking up in the middle of the night, the first step toward better sleep is to figure out what’s triggering your insomnia. Once you do that, you can take action to prevent it from becoming chronic — a clinical sleep disorder that should be treated by a sleep-medicine specialist. Stressful and upsetting experiences like the death of a loved one or the loss of a job — two widespread realities of Covid-19 — are known psychological triggers for insomnia. If your insomnia is tied to such an event, the quickest way to get help is to call your doctor. One thing many doctors suggest is cognitive behavioral therapy, or C.B.T. C.B.T., or C.B.T.-I. for insomnia, is a standard treatment for both acute and chronic insomnia and includes a variety of techniques. Meditation, mindfulness and muscle relaxation can help people whose sleep problems are tied to a stressful event. C.B.T. for insomnia typically lasts from six to eight weeks and “works in about two-thirds to three-quarters of patients,” said Jennifer Martin, a psychologist and professor of medicine at the University of California, Los Angeles, David Geffen School of Medicine. © 2020 The New York Times Company

Keyword: Sleep; Stress
Link ID: 27581 - Posted: 11.16.2020