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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.

Related chapters from BN: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 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

Related chapters from BN: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and 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.

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

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

Related chapters from BN: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep; Chapter 7: Vision: From Eye to Brain
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

Related chapters from BN: Chapter 18: Attention and Higher Cognition; Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 14: Attention and Higher Cognition; Chapter 10: Biological Rhythms and Sleep
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

Related chapters from BN: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and 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.

Related chapters from BN: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and 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

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 4: Development of the Brain; Chapter 10: Biological Rhythms and Sleep
Link ID: 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

Related chapters from BN: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep; Chapter 11: Emotions, Aggression, and Stress
Link ID: 27581 - Posted: 11.16.2020

By Nicholas Bakalar Weighted blankets, which have long been popular aids to induce calm, could help reduce insomnia, a new study suggests. Swedish researchers studied 121 patients with depression, bipolar disorder and other psychiatric diagnoses, all of whom had sleep problems. They randomly assigned them to two groups. The first slept with an 18-pound blanket weighted with metal chains, and the second with an identical looking three-pound plastic chain blanket. The study, in the Journal of Clinical Sleep Medicine, used the Insomnia Severity Index, a 28-point questionnaire that measures sleep quality, and participants wore activity sensors on their wrists to measure sleep time, awakenings and daytime activity. More than 42 percent of those using the heavy blanket scored low enough on the Insomnia Severity Index to be considered in remission from their sleep troubles, compared with 3.6 percent of the controls. The likelihood of having a 50 percent reduction on the scale was nearly 26 times greater in the weighted blanket group. The weighted blankets did not have a significant effect on total sleep time, but compared with the controls, the users had a significant decrease in wakenings after sleep onset, less daytime sleepiness and fewer symptoms of depression and anxiety. The senior author, Dr. Mats Adler of the Karolinska Institute in Stockholm, acknowledged that this is only one study and doesn’t provide scientific proof that the blankets work. “I have colleagues using it, and they love it,” he said, “but that’s not proof. This study is an indication that they may work, but more studies should be done.” © 2020 The New York Times Company

Related chapters from BN: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 27524 - Posted: 10.16.2020

By Benedict Carey The swarm of insects — sometimes gnats, sometimes wasps or flying ants — arrived early in this year of nightmares. With summer came equally unsettling dreams: of being caught in a crowd, naked and mask-less; of meeting men in white lab coats who declared, “We dispose of the elders.” Autumn has brought still other haunted-house dramas, particularly for women caring for a vulnerable relative or trying to manage virtual home-schooling. “I am home-schooling my 10-year-old,” one mother told researchers in a recent study of pandemic dreams. “I dreamed that the school contacted me to say it had been decided that his whole class would come to my home and I was supposed to teach all of them for however long the school remained closed.” Deirdre Barrett, a psychologist at Harvard Medical School and the author of “Pandemic Dreams,” has administered dream surveys to thousands of people in the last year, including the one with the home-schooling mother. “At least qualitatively, you see some shifts in content of dreams from the beginning of the pandemic into the later months,” Dr. Barrett said. “It’s an indication of what is worrying people most at various points during the year.” Dr. Barrett is the editor in chief of the journal Dreaming, which in its September issue posted four new reports on how the sleeping brain has incorporated the threat of Covid-19. The findings reinforce current thinking about the way that waking anxiety plays out during REM sleep: in images or metaphors representing the most urgent worries, whether these involve catching the coronavirus (those clouds of insects) or violating mask-wearing protocols. Taken together, the papers also hint at an answer to a larger question: What is the purpose of dreaming, if any? The answers that science has on offer can seem mutually exclusive, or near so. Freud understood dreams as wish fulfillment; the Finnish psychologist Antti Revonsuo saw them as simulations of pending threats. In recent years, brain scientists have argued that REM sleep — the period of sleep during which most dreaming occurs — bolsters creative thinking, learning and emotional health, providing a kind of unconscious psychotherapy. Then again, there is some evidence that dreaming serves little or no psychological purpose — that it is no more than a “tuning of the mind in preparation for awareness,” as Dr. J. Allan Hobson, a Harvard psychiatrist, has said. © 2020 The New York Times Company

Related chapters from BN: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep; Chapter 11: Emotions, Aggression, and Stress
Link ID: 27514 - Posted: 10.07.2020

By Veronique Greenwood Hummingbirds live a life of extremes. The flitting creatures famously have the fastest metabolisms among vertebrates, and to fuel their zippy lifestyle, they sometimes drink their own body weight in nectar each day. But the hummingbirds of the Andes in South America take that extreme lifestyle a step further. Not only must they work even harder to hover at altitude, but during chilly nights, they save energy by going into exceptionally deep torpor, a physiological state similar to hibernation in which their body temperature falls by as much as 50 degrees Fahrenheit. Then, as dawn approaches, they start to shiver, sending their temperatures rocketing back up to 96 degrees. It’s an intense process, says Andrew McKechnie, a professor of zoology at the University of Pretoria in South Africa. “You’ve got a bird perching on a branch, whose body temp might be 20 degrees Celsius,” or 68 Fahrenheit, he said. “And it’s cranking out the same amount of heat as when it is hovering in front of a flower.” Now, Dr. McKechnie and colleagues reported on Wednesday in Biology Letters that the body temperatures of Andean hummingbirds in torpor and the amount of time they spend in this suspended animation vary among species, with one particular set of species, particularly numerous in the Andes, tending to get colder and go longer than others. They also report one of the lowest body temperatures ever seen in hummingbirds: just under 38 degrees Fahrenheit. On a trip to the Andes about five years ago, Blair Wolf, a professor of biology at the University of New Mexico and an author of the new paper, and his colleagues captured 26 of the little birds for overnight observation. They measured the hummingbirds’ body temperatures as they roosted for the night and found that almost all of them entered torpor, showing a steep decline in temperature partway through the night. © 2020 The New York Times Company

Related chapters from BN: Chapter 13: Homeostasis: Active Regulation of the Internal Environment; Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment; Chapter 10: Biological Rhythms and Sleep
Link ID: 27463 - Posted: 09.09.2020

By Charlotte Hartley “I was at home and that scary red monster thing from that stupid Looney Tunes show was hanging around,” reads the dream diary of Izzy, a teenage girl. “There were lots of them trying to get in and I was scared to death.” Like many people, Izzy dreams about strange characters in unlikely situations. But according to a new study, in which researchers analyzed thousands of dreams with an automated tool, Izzy’s dream is probably just an expression of her adolescent anxieties—a funhouse reflection of her everyday experiences. The researchers say the tool, which identifies and quantifies the characters, interactions, and emotions of dreams, could help psychologists quickly identify potential stressors and mental health issues among their patients. Throughout history, people have tried to extract hidden meaning from dreams. Ancient Babylonians believed dreams contained prophecies, whereas ancient Egyptians revered them as messages from the gods. In the 1890s, Sigmund Freud assigned symbolic meanings to dream characters, objects, and scenarios—with an emphasis on sex and aggression. Today, however, most psychologists support the “continuity hypothesis,” which posits that dreams are a continuation of what happens in waking life. Indeed, numerous studies have shown that dreams often reflect day-to-day activities and can act as a sort of nocturnal therapist, helping people process experiences and prepare for real-life problems. “If we can understand our dreams better at scale, then maybe we can also tailor technologies that improve our waking life,” says Luca Maria Aiello, a computational social scientist at Nokia Bell Labs and co-author of the study. © 2020 American Association for the Advancement of Science

Related chapters from BN: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 27434 - Posted: 08.26.2020

By Gretchen Reynolds People who are evening types go to bed later and wake up later than morning types. They also tend to move around far less throughout the day, according to an interesting new study of how our innate body clocks may be linked to our physical activity habits. The study, one of the first to objectively track daily movements of a large sample of early birds and night owls, suggests that knowing our chronotype might be important for our health. In recent years, a wealth of new science has begun explicating the complex roles of cellular clocks and chronotypes in our health and lifestyles. Thanks to this research, we know that each of us contains a master internal body clock, located in our brains, that tracks and absorbs outside clues, such as ambient light, to determine what time it is and how our bodies should react. This master clock directs the rhythmic release of hormones, such as melatonin, and other chemicals that affect sleep, wakefulness, hunger and many other physiological systems. Responding in part to these biochemical signals, as well as our genetic inclinations and other factors, we each develop a chronotype, which is our overall biological response to the daily passage of time. Chronotypes are often categorized into one of three groups: morning, day or night. Someone with a morning chronotype will naturally wake early; feel most alert and probably hungry in the morning; and be ready for bed before Colbert comes on. Day types tend to wake a bit later and experience peak alertness a few hours deeper into the day. And evening types rise as late as possible and remain vampirically wakeful well past dark. Our chronotypes are not immutable, though. Research shows that they have a yearslong rhythm of their own, with most people harboring a morning or day chronotype when young, an evening version during adolescence and young adulthood, and a return to a day or morning type by middle age. But some people remain night owls lifelong. Our shifting chronotypes are known to affect our health, especially if someone is an evening type. In past studies, people identified as evening types were more likely to develop heart disease, obesity, diabetes and other metabolic conditions than people with other chronotypes. They also tended to exercise less and sit far more, which some researchers suspect contributes to their risks for health problems. © 2020 The New York Times Company

Related chapters from BN: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 27425 - Posted: 08.18.2020

By Helen Macdonald I found a dead common swift once, a husk of a bird under a bridge over the River Thames, where sunlight from the water cast bright scribbles on the arches above. I picked it up, held it in my palm, saw the dust in its feathers, its wings crossed like dull blades, its eyes tightly closed, and realized that I didn’t know what to do. This was a surprise. Encouraged by books, I’d always been the type of Gothic amateur naturalist who preserved interesting bits of the dead. I cleaned and polished fox skulls; disarticulated, dried and kept the wings of roadkill birds. But I knew, looking at the swift, that I could not do anything like that to it. The bird was suffused with a kind of seriousness very akin to holiness. I didn’t want to leave it there, so I took it home, swaddled it in a towel and tucked it in the freezer. It was in early May the next year, as soon as I saw the first returning swifts flowing down from the clouds, that I knew what I had to do. I went to the freezer, took out the swift and buried it in the garden one hand’s-width deep in earth newly warmed by the sun. Swifts are magical in the manner of all things that exist just a little beyond understanding. Once they were called the “Devil’s bird,” perhaps because those screaming flocks of black crosses around churches seemed pulled from darkness, not light. But to me, they are creatures of the upper air, and of their nature unintelligible, which makes them more akin to angels. Unlike all other birds I knew as a child, they never descended to the ground. When I was young, I was frustrated that there was no way for me to know them better. They were so fast that it was impossible to focus on their facial expressions or watch them preen through binoculars. They were only ever flickering silhouettes at 30, 40, 50 miles an hour, a shoal of birds, a pouring sheaf of identical black grains against bright clouds. There was no way to tell one bird from another, nor to watch them do anything other than move from place to place, although sometimes, if the swifts were flying low over rooftops, I’d see one open its mouth, and that was truly uncanny, because the gape was huge, turning the bird into something uncomfortably like a miniature basking shark. Even so, watching them with the naked eye was rewarding in how it revealed the dynamism of what before was merely blankness. Swifts weigh about 1½ ounces, and their surfing and tacking against the pressures of oncoming air make visible the movings of the atmosphere. © 2020 The New York Times Company

Related chapters from BN: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 27391 - Posted: 07.29.2020

By Baland Jalal Imagine waking up in the middle of the night to an unearthly figure with blood dripping down its fangs. You try to scream, but you can’t. You can’t move a single muscle! If this sounds familiar, you’ve probably experienced an episode of sleep paralysis, which involves the inability to move or speak upon falling asleep or awakening and is often coupled with hallucinations. About one in five people have had sleep paralysis at least once. But despite its prevalence, it has largely remained a mystery. For centuries, cultures across the world have attributed these hallucinations to black magic, mythical monsters, even paranormal activity. Scientists have since dismissed such explanations, yet these cultural beliefs persist. In fact, my and my colleagues’ research, conducted over roughly a decade in six different countries, suggests that beliefs about sleep paralysis can dramatically shape the physical and psychological experience, revealing a striking type of mind-body interaction. Sleep paralysis is caused by what appears to be a basic brain glitch at the interface between wakefulness and rapid eye movement (REM) sleep. During REM, you have intensely lifelike dreams. To prevent you from acting out these realistic dreams (and hurting yourself!), your brain has a clever solution: it temporarily paralyzes your entire body. Indeed, your brain has a “switch” (a handful of neurochemicals) that tilts you between sleep and wakefulness. Sometimes the “switch” fails, however—your brain inadvertently wakes up while your body is still under the “spell” of REM paralysis, leaving you stuck in a paradoxical state between parallel realities: wakefulness and REM sleep. During sleep paralysis, the crisp dreams of REM “spill over” into waking consciousness like a dream coming alive before your eyes—fanged figures and all. © 2020 Scientific American

Related chapters from BN: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 27367 - Posted: 07.16.2020

By Nicholas Bakalar Artificial outdoor light at night may disrupt adolescents’ sleep and raise the risk for psychiatric disorders, a new study suggests. Researchers tracked the intensity of outdoor light in representative urban and rural areas across the country using satellite data from the National Oceanic and Atmospheric Administration. They interviewed more than 10,123 adolescents living in these neighborhoods about their sleep patterns, and assessed mental disorders using well-validated structured scales. They also interviewed the parents of more than 6,000 of the teenagers about their children. The study, in JAMA Psychiatry, found that the more intense the lighting in your neighborhood, the more sleep was disrupted and the greater the risk for depression and anxiety. After adjustment for other factors such as sex, race, parental education and population density, they found that compared with the teenagers in the one-quarter of neighborhoods with the lowest levels of outdoor light, those in the highest went to bed, on average, 29 minutes later and reported 11 fewer minutes of sleep. Adolescents living in the most intensely lit neighborhoods had a 19 percent increased risk for bipolar illness, and a 7 percent increased risk for depression. The study is observational, and does not prove cause and effect. The senior author, Kathleen R. Merikangas, a senior investigator with the National Institute of Mental Health, said that future policy changes could make a difference. In the meantime, she said, “At least as individuals, we ought to try to minimize exposure to light at night.” © 2020 The New York Times Company

Related chapters from BN: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep; Chapter 4: Development of the Brain
Link ID: 27362 - Posted: 07.15.2020

By Anna Goldfarb It’s understandable that you may be struggling to fall asleep these days. Our world has been turned upside down, so it is especially hard to unplug from the day and get the high-quality sleep your body needs. “Almost every single patient I’m speaking with has insomnia,“ said Dr. Alon Y. Avidan, a professor and vice chair in the department of neurology at the David Geffen School of Medicine at the University of California, Los Angeles, and director of the U.C.L.A. Sleep Disorders Center. “Especially now with Covid-19, we have an epidemic of insomnia. We call it Covid-somnia.” An increase in anxiety in both children and adults is affecting our ability to fall asleep. Additionally, our lifestyles have changed drastically as people observe sheltering in place guidelines. With more people staying indoors, it can mean they are not getting enough light exposure. “Without light exposure in the morning,” Dr. Avidan said, people “lose the circadian cues that are so fundamentally important in setting up appropriate and normal sleep-wake time.” There are nonmedical ways to help you sleep better: Meditation, turning off screens early in the night, warm showers and cool bedrooms can help your body rest better. But if these options don’t work, or if you are ready for the next step, you may have considered trying melatonin supplements. These pills are commonplace enough that you have most likely heard of them and seen them in your local pharmacy. Here’s what you need to know about the pros and cons of using melatonin supplements for sleeping difficulties. What is melatonin? Melatonin is a hormone that helps regulate sleep timing. It is produced in the pea-size pineal gland, which is nestled in the middle of your brain and syncs melatonin production with the rising and setting of the sun. According to the National Sleep Foundation, the gland remains inactive during the day but switches on around 9 p.m. (when it’s generally dark) to flood the brain with melatonin for the next 12 hours. © 2020 The New York Times Company

Related chapters from BN: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 5: Hormones and the Brain
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep; Chapter 8: Hormones and Sex
Link ID: 27360 - Posted: 07.14.2020

By Richard Sandomir Dr. William Dement, whose introduction to the mysteries of slumber as a postgraduate student in the 1950s led him to become an eminent researcher of sleep disorders and to preach the benefits of a good night’s sleep, died on June 17 in Stanford, Calif. He was 91. His son, Nick, a physician, said the cause was complications of a heart procedure. Dr. Dement spent his working life as a popular professor in the department of psychiatry at Stanford University, where he started what is believed to be the world’s first successful sleep disorders clinic. He taught a class on sleep and dreams that drew as many as 1,200 students. When he awakened dozing students with spritzes from a water gun, Dr. Dement gave them extra credit if they recovered and shouted, “Drowsiness is red alert!” — his rallying cry to make sleep deprivation a public health priority. Drowsiness was the last step before falling asleep, he often said. Sleep deprivation put people at a higher risk of an accident on the road, diminished their productivity, increased the likelihood of their making mistakes, made them irritable and actually hurt their ability to fall asleep. “Bill Dement was an evangelist about sleep,” Dr. Rafael Pelayo, a Stanford psychiatry professor who succeeded Dr. Dement in leading the sleep class, said in a phone interview. “He felt that not enough people knew about sleep disorders, and he thought of his students as multipliers who would tell the world about them.” Dr. Dement’s expertise led to his appointment as chairman of a federal commission on sleep disorders. The commission reported in 1992 that 40 million Americans had undiagnosed, untreated, mistreated or chronic sleep problems — findings that led Congress to establish the National Center on Sleep Disorders Research, within the National Institutes of Health, in 1993. When Dr. Dement testified on Capitol Hill five years later about the sleep center’s progress, he said he was pleased with its research but disappointed that the government had not sounded loud enough alarms about the serious, sometimes fatal, consequences of unhealthful sleep. © 2020 The New York Times Company

Related chapters from BN: Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep
Link ID: 27333 - Posted: 06.29.2020