By Meghan Rosen In endurance athletes, some brain power may come from an unexpected source. Marathon runners appear to rely on myelin, the fatty tissue bundled around nerve fibers, for energy during a race, scientists report October 10 in a paper posted at bioRxiv.org. In the day or two following a marathon, this tissue seems to dwindle drastically, brain scans of runners reveal. Two weeks after the race, the brain fat bounces back to nearly prerace levels. The find suggests that the athletes burn so much energy running that they need to tap into a new fuel supply to keep the brain operating smoothly. “This is definitely an intriguing observation,” says Mustapha Bouhrara, a neuroimaging scientist at the National Institute on Aging in Baltimore. “It is quite plausible that myelin lipids are used as fuel in extended exercise.” If what the study authors are seeing is real, he says, the work could have therapeutic implications. Understanding how runners’ myelin recovers so rapidly might offer clues for developing potential treatments — like for people who’ve lost myelin due to aging or neurodegenerative disease. Much of the human brain contains myelin, tissue that sheathes nerve fibers and acts as an insulator, like rubber coating an electrical wire. That insulation lets electrical messages zip from nerve cell to nerve cell, allowing high-speed communication that’s crucial for brain function. The fatty tissue seems to be a straightforward material with a straightforward job, but there’s likely more to it than that, says Klaus-Armin Nave, a neurobiologist at the Max Planck Institute for Multidisciplinary Sciences in Göttingen, Germany. “For the longest time, it was thought that myelin sheathes were assembled, inert structures of insulation that don’t change much after they’re made,” he says. Today, there’s evidence that myelin is a dynamic structure, growing and shrinking in size and abundance depending on cellular conditions. The idea is called myelin plasticity. “It’s hotly researched,” Nave says. © Society for Science & the Public 2000–2023.

Keyword: Glia; Multiple Sclerosis
Link ID: 28983 - Posted: 11.01.2023

By Jake Buehler A fruit bat hanging in the corner of a cave stirs; it is ready to move. It scans the space to look for a free perch and then takes flight, adjusting its membranous wings to angle an approach to a spot next to one of its fuzzy fellows. As it does so, neurological data lifted from its brain is broadcast to sensors installed in the cave’s walls. This is no balmy cave along the Mediterranean Sea. The group of Egyptian fruit bats is in Berkeley, California, navigating an artificial cave in a laboratory that researchers have set up to study the inner workings of the animals’ minds. The researchers had an idea: that as a bat navigates its physical environment, it’s also navigating a network of social relationships. They wanted to know whether the bats use the same or different parts of their brain to map these intersecting realities. In a new study published in Nature in August, the scientists revealed that these maps overlap. The brain cells informing a bat of its own location also encode details about other bats nearby — not only their location, but also their identities. The findings raise the intriguing possibility that evolution can program those neurons for multiple purposes to serve the needs of different species. The neurons in question are located in the hippocampus, a structure deep within the mammalian brain that is involved in the creation of long-term memories. A special population of hippocampal neurons, known as place cells, are thought to create an internal navigation system. First identified in the rat hippocampus in 1971 by the neuroscientist John O’Keefe, place cells fire when an animal is in a particular location; different place cells encode different places. This system helps animals determine where they are, where they need to go and how to get from here to there. In 2014, O’Keefe was awarded the Nobel Prize for his discovery of place cells, and over the last several decades they have been identified in multiple primate species, including humans. However, moving from place to place isn’t the only way an animal can experience a change in its surroundings. In your home, the walls and furniture mostly stay the same from day to day, said Michael Yartsev, who studies the neural basis of natural behavior at the University of California, Berkeley and co-led the new work. But the social context of your living space could change quite regularly. © 2023 An editorially independent publication supported by the Simons Foundation.

Keyword: Learning & Memory
Link ID: 28982 - Posted: 11.01.2023

Michaeleen Doucleff For several months now, I've been studying how the new medications, Ozempic and Wegovy, cause dramatic weight loss. Both medications contain a compound, semaglutide, that squelches hunger like a fly swatter smashes a mosquito. People who take the medication say they no longer have constant cravings for food, so they eat less frequently. The drug seems to quiet what some people call "food noise," the constant internal chatter telling them to eat. While reading study after study about Wevgovy and Ozempic, I learned that the drug mimics a hormone that our bodies naturally make when we're eating food. It's called GLP-1. This made me wonder: Could we increase levels of this hormone by changing our diet? Turns out, the answer is yes – you can increase your body's production of GLP-1 with your diet, says Frank Duca, who studies metabolic diseases at the University of Arizona. One of the key foods that triggers its release is a food most Americans struggle to eat enough of, even though it comes with a cornucopia of health benefits. Yup, I'm talking about fiber. "Whenever my family finds out that I'm studying obesity or diabetes, they say, 'Oh, what's the wonder drug? What do I need to take? What do I need to do?'" Duca explains. "And I say, 'Eat more fiber.' " But here's the hitch. Not all fiber works the same way. Duca and other researchers are beginning to show that particular types of fibers are more potent at triggering GLP-1 release and at regulating hunger than others. "We're seeing now that companies are adding fiber to foods, but a lot of the time, they don't add the kind of fiber that's super beneficial for you," Duca says. To understand why fiber is so important for producing GLP-1, let's look at what happens when you don't eat much fiber. Let's say you wake up in the morning feeling hungry and you eat two slices of white bread and a fried egg. As the digested food moves into the small intestine, many of the nutrients, such as the carbohydrates, fats and amino acids, trigger an avalanche of activity in your blood and brain. "The food activates cells in your intestine, which then release a ton of hormones," says Sinju Sundaresan, who's a gut physiologist at Midwestern University. About 20 of these hormones, including GLP-1, are known as satiation hormones. © 2023 npr

Keyword: Obesity
Link ID: 28981 - Posted: 11.01.2023

by Giorgia Guglielmi / The ability to see inside the human brain has improved diagnostics and revealed how brain regions communicate, among other things. Yet questions remain about the replicability of neuroimaging studies that aim to connect structural or functional differences to complex traits or conditions, such as autism. Some neuroscientists call these studies ‘brain-wide association studies’ — a nod to the ‘genome-wide association studies,’ or GWAS, that link specific variants to particular traits. But unlike GWAS, which typically analyze hundreds of thousands of genomes at once, most published brain-wide association studies involve, on average, only about two dozen participants — far too few to yield reliable results, a March analysis suggests. Spectrum talked to Damien Fair, co-lead investigator on the study and director of the Masonic Institute for the Developing Brain at the University of Minnesota in Minneapolis, about solutions to the problem and reproducibility issues in neuroimaging studies in general. Spectrum: How have neuroimaging studies changed over time, and what are the consequences? Damien Fair: The realization that we could noninvasively peer inside the brain and look at how it’s reacting to certain types of stimuli blew open the doors on studies correlating imaging measurements with behaviors or phenotypes. But even though there was a shift in the type of question that was being asked, the study design stayed identical. That has caused a lot of the reproducibility issues we’re seeing today, because we didn’t change sample sizes. The opportunity is huge right now because we finally, as a community, are understanding how to use magnetic resonance imaging for highly reliable, highly reproducible, highly generalizable findings. S: Where did the reproducibility issues in neuroimaging studies begin? DF: The field got comfortable with a certain type of study that provided significant and exciting results, but without having the rigor to show how those findings reproduced. For brain-wide association studies, the importance of having large samples just wasn’t realized until more recently. It was the same problem in the early age of genome-wide association studies looking at common genetic variants and how they relate to complex traits. If you’re underpowered, highly significant results may not generalize to the population. © 2023 Simons Foundation

Keyword: Brain imaging
Link ID: 28980 - Posted: 11.01.2023

By Paula Span A year ago, the Food and Drug Administration announced new regulations allowing the sale of over-the-counter hearing aids and setting standards for their safety and effectiveness. That step — which was supposed to take three years but required five — portended cheaper, high-quality hearing aids that people with mild to moderate hearing loss could buy online or at local pharmacies and big stores. So how’s it going? It’s a mixed picture. Manufacturers and retailers have become serious about making hearing aids more accessible and affordable. Yet the O.T.C. market remains confusing, if not downright chaotic, for the mostly older consumers the new regulations were intended to help. The past year also brought renewed focus on the importance of treating hearing loss, which affects two-thirds of people over age 70. Researchers at Johns Hopkins University published the first randomized clinical trial showing that hearing aids could help reduce the pace of cognitive decline. Some background: In 2020, the influential Lancet Commission on Dementia Prevention, Intervention and Care identified hearing loss as the greatest potentially modifiable risk factor for dementia. Previous studies had demonstrated a link between hearing loss and cognitive decline, said Dr. Frank Lin, an otolaryngologist and epidemiologist at Johns Hopkins and lead author of the new research. “What remained unanswered was, If we treat hearing loss, does it actually reduce cognitive loss?” he said. The ACHIEVE study (for Aging and Cognitive Health Evaluation in Elders) showed that, at least for a particular group of older adults, it could. Of nearly 1,000 people ages 70 to 84 with untreated mild to moderate hearing loss, half received hearing assessments from audiologists, were fitted with midpriced hearing aids and were counseled on how to use them for several months. The control group participated in a health education program. Over three years, the study found that hearing-aid use had scant effect on healthy volunteers at low risk of cognitive loss. But among participants who were older and less affluent, hearing aids reduced the rate of cognitive decline by 48 percent, compared with the control group, a difference the researchers deemed “clinically meaningful.” © 2023 The New York Times Company

Keyword: Hearing; Alzheimers
Link ID: 28979 - Posted: 11.01.2023

By Darren Incorvaia The idea of a chicken running around with its head cut off, inspired by a real-life story, may make it seem like the bird doesn’t have much going on upstairs. But Sonja Hillemacher, an animal behavior researcher at the University of Bonn in Germany, always knew that chickens were more than mindless sources of wings and nuggets. “They are way smarter than you think,” Ms. Hillemacher said. Now, in a study published in the journal PLOS One on Wednesday, Ms. Hillemacher and her colleagues say they have found evidence that roosters can recognize themselves in mirrors. In addition to shedding new light on chicken intellect, the researchers hope that their experiment can prompt re-evaluations of the smarts of other animals. The mirror test is a common, but contested, test of self-awareness. It was introduced by the psychologist Gordon Gallup in 1970. He housed chimpanzees with mirrors and then marked their faces with red dye. The chimps didn’t seem to notice until they could see their reflections, and then they began inspecting and touching the marked spot on their faces, suggesting that they recognized themselves in the mirror. The mirror test has since been used to assess self-recognition in many other species. But only a few — such as dolphins and elephants — have passed. After being piloted on primates, the mirror test was “somehow sealed in a nearly magical way as sacred,” said Onur Güntürkün, a neuroscientist at Ruhr University Bochum in Germany and an author of the study who worked with Ms. Hillemacher and Inga Tiemann, also at the University of Bonn. But different cognitive processes are active in different situations, and there’s no reason to think that the mirror test is accurate for animals with vastly different sensory abilities and social systems than what chimps have. The roosters failed the classic mirror test. When the team marked them with pink powder, the birds showed no inclination to inspect or touch the smudge in front of the mirror the way that Dr. Gallup’s chimps did. As an alternative, the team tested rooster self-awareness in a more fowl friendly way. © 2023 The New York Times Company

Keyword: Consciousness; Intelligence
Link ID: 28978 - Posted: 10.28.2023

By Christa Lesté-Lasserre A gray cat stares quietly at a nearby orange tabby, squinting her eyes, flattening her ears, and licking her lips. The tabby glares back, wrinkles his nose, and pulls back his whiskers. Cat people know what’s about to go down: a fight. If looks and growls don’t resolve the budding tiff, claws will pop out and fur will fly. Those faces aren’t the only ones cats make at each other, of course—not by a long shot. In a study published this month in Behavioural Processes, researchers tallied 276 different feline facial expressions, used to communicate hostile and friendly intent and everything in between. What’s more, the team found, we humans might be to thank: Our feline friends may have evolved this range of sneers, smiles, and grimaces over the course of their 10,000-year history with us. “Many people still consider cats—erroneously—to be a largely nonsocial species,” says Daniel Mills, a veterinary behaviorist at the University of Lincoln who was not involved in the study. The facial expressions described in the new study suggest otherwise, he notes. “There is clearly a lot going on that we are not aware of.” Cats can be solitary creatures, but they often form friendships with fellow kitties in people’s homes or on the street; feral cats can live in colonies of thousands, sometimes taking over entire islands. Lauren Scott, a medical student and self-described cat person at the University of Kansas, long wondered how all these felines communicated with one another. There has to be love and diplomacy, not just fighting, yet most studies of feline expression have focused on aggression. Fortunately in 2021, Scott was studying at the University of California, Los Angeles (UCLA), just minutes from the CatCafé Lounge. There, human visitors can interact—and even do yoga—with dozens of group-housed, adoptable cats. From August to June, Scott video recorded 194 minutes of cats’ facial expressions, specifically those aimed at other cats, after the café had closed for the day. Then she and evolutionary psychologist Brittany Florkiewicz, also at UCLA at the time but now at Lyon College, coded all their facial muscle movements—excluding any related to breathing, chewing, yawning, and the like.

Keyword: Emotions; Evolution
Link ID: 28977 - Posted: 10.28.2023

By Charles Digges Is there any kind of fence that can make humans and elephants good neighbors? It’s a question Dominique Gonçalves has had to ponder as she leads the elephant ecology project at Mozambique’s Gorongosa National Park, which is not surrounded by a physical barrier. A number of pioneering studies throughout Sub-Saharan Africa over the past several years showed a solution that was simple and natural: bees. As it turns out, the tiny, ubiquitous honeybee has the power to terrify a mammal that’s 22 million times its size. In fact, even the sound of the insect’s buzz is enough to send a family of elephants into a panic, showed studies by Lucy King, an Oxford zoologist and preeminent researcher in human-elephant coexistence at the nonprofit Save the Elephants. Upon hearing the telltale hum, elephants will run, kick up dust, shake their heads as if trying to swat the bees out of the air, trumpeting distressed warnings to other elephants as they flee. Of course, a bee’s stinger can’t penetrate the thick hide of an elephant. But when bees swarm—and African bees swarm aggressively—hundreds of bees might sting an elephant in its most sensitive areas, like the trunk, the mouth, and eyes. And it works. Building on King’s insights, Paola Branco of the University of Idaho conducted a massive two-year-long experiment in Gorongosa that culminated in a 2019 paper she co-authored with King, Marc Stalmans, Gorongosa’s director of scientific services, Princeton zoologist Robert Pringle, and others.1 Their research aimed to settle tensions between human farmers and the park’s growing population of marauding pachyderms—with the help of bees. © 2023 NautilusNext Inc.,

Keyword: Emotions; Evolution
Link ID: 28976 - Posted: 10.28.2023

By Bruce Bower Female chimps living in an East African forest experience menopause and then survive years, even decades, after becoming biologically unable to reproduce. The apes are the first known examples of wild, nonhuman primates to go through the fertility-squelching hormonal changes and live well beyond their reproductive years. The finding raises new questions about how menopause evolved, UCLA evolutionary anthropologist Brian Wood and colleagues conclude in the Oct. 27 Science. Until now, females who experience menopause and keep living for years have been documented only in humans and five whale species. It’s unclear what evolutionary benefit exists to explain such longevity past the point of being able to give birth and pass on one’s genes. Although evolutionary explanations for menopause remain debatable, the new finding reflects an especially close genetic relationship between humans and chimps, Wood says. “Both [species] are more predisposed to post-reproductive survival than other great apes.” Some evidence suggests that female fertility ends at similar ages in humans and chimps (Pan troglodytes) if our ape relatives live long enough, says anthropologist Kristen Hawkes of the University of Utah in Salt Lake City. But in other studies, female chimps, such as those studied by Jane Goodall at Tanzania’s Gombe National Park starting in 1960, aged quickly and often died in their early 30s, usually while still having menstrual cycles, she says. “What’s surprising [in Wood’s study] is so many females living so long after menopause,” Hawkes says. © Society for Science & the Public 2000–2023.

Keyword: Hormones & Behavior; Evolution
Link ID: 28975 - Posted: 10.28.2023

By Hallie Levine Every 40 seconds, someone in the United States has a stroke, and about three-quarters occur in people ages 65 and older. “As people age, their arteries have a tendency to become less flexible,” and clogged arteries are more likely, says Doris Chan, an interventional cardiologist at NYU Langone Health. This hikes the risk of an ischemic stroke — the most common type — when a blood vessel to the brain becomes blocked by a blood clot. But about 80 percent of all strokes are preventable, according to the Centers for Disease Control and Prevention. And the lifestyle steps you take can be especially powerful in fending off stroke. Here’s what you can do to reduce your risk. 1. Watch these issues. Keeping certain conditions at bay or managing them properly can cut the likelihood of a stroke. Take high blood pressure, which some research suggests is responsible for almost half of strokes. A heart-healthy eating plan may help control it. Also, try to limit sodium to less than 1,500 milligrams a day, maintain a healthy weight and exercise regularly, says Sahil Khera, an interventional cardiologist at the Mount Sinai Hospital in New York. If your blood pressure is high even with the above measures, ask your doctor what levels you should strive for and whether meds are appropriate. Staying out of the hypertensive range can be challenging with age because of the higher potential for medication side effects. While blood pressure below 120/80 can reduce cardiovascular risk, that target should be adjusted if side effects such as dizziness occur, says Hardik Amin, an associate professor of neurology at the Yale School of Medicine in New Haven, Conn. Another important condition to watch for is atrial fibrillation (AFib), an irregular and often rapid heartbeat, which affects at least 10 percent of people over age 80, according to a 2022 study in the Journal of the American College of Cardiology. People with AFib are about five times as likely to have a stroke.

Keyword: Stroke; Drug Abuse
Link ID: 28974 - Posted: 10.28.2023

By Laura Dattaro A brain is nothing if not communicative. Neurons are the chatterboxes of this conversational organ, and they speak with one another by exchanging pulses of electricity using chemical messengers called neurotransmitters. By repeating this process billions of times per second, a brain converts clusters of chemicals into coordinated actions, memories and thoughts. Researchers study how the brain works by eavesdropping on that chemical conversation. But neurons talk so loudly and often that if there are other, quieter voices, it might be hard to hear them. For most of the 20th century, neuroscientists largely agreed that neurons are the only brain cells that propagate electrical signals. All the other brain cells, called glia, were thought to serve purely supportive roles. Then, in 1990, a curious phenomenon emerged: Researchers observed an astrocyte, a subtype of glial cell, responding to glutamate, the main neurotransmitter that generates electrical activity. In the decades since, research teams have come up with conflicting evidence, some reporting that astrocytes signal, and others retorting that they definitely do not. The disagreement played out at conferences and in review after review of the evidence. The two sides seemed irreconcilable. A new paper published in Nature in September presents the best proof yet that astrocytes can signal, gathered over eight years by a team co-led by Andrea Volterra, visiting faculty at the Wyss Center for Bio and Neuro Engineering in Geneva, Switzerland. The study includes two key pieces of evidence: images of glutamate flowing from astrocytes, and genetic data suggesting that these cells, dubbed glutamatergic astrocytes, have the cellular machinery to use glutamate the way neurons do. The paper also helps explain the decades of contradictory findings. Because only some astrocytes can perform this signaling, both sides of the controversy are, in a sense, right: A researcher’s results depend on which astrocytes they sampled. All Rights Reserved © 2023

Keyword: Glia
Link ID: 28972 - Posted: 10.25.2023

Christie Wilcox Adult horsehair worms look about how you’d expect given their name: They’re long, noodlelike creatures that resemble wiggling horse hairs. They live and reproduce in water, but their young only develop inside the bodies of other animals—usually terrestrial insects such as praying mantises. Once they’ve finished growing inside their unwitting vessel, the worms must convince their hosts to drown themselves to complete their life cycle. How these parasites manage to lethally manipulate their hosts has long puzzled scientists. Researchers behind a new study published today in Current Biology suggest horsehair worms possess hundreds of genes that allow them to hijack a mantis’ movement—and they may have acquired these genes directly from their ill-fated hosts. “The results are amazing,” says Clément Gilbert, an evolutionary biologist at the University of Paris-Saclay who wasn’t involved in the work. If it turns out to be true that so many of the mantises’ genes jumped over to the parasitic worms—a process known as horizontal gene transfer—then “this is by far the highest number of horizontally transferred genes that have been reported between two species of animals,” he adds. The phenomenon of parasites mind-controlling their hosts to an early grave has always intrigued Tappei Mishina, an evolutionary biologist at Kyushu University and the RIKEN Center for Biosystems Dynamics Research. “For more than 100 years, there have been horrifying observations of terrestrial insects jumping into water right before our eyes all over the world,” he says. He teamed up with ecologist Takuya Sato of the Center for Ecological Research at Kyoto University to investigate the genetic basis of their parasitism. They focused on horsehair or gordian worms, a group of parasitic animals related to nematodes. Many have complex life cycles involving multiple hosts, and the ones that live in freshwater must generally find their way into an insect to finish developing into adults. The genus Mishina, Sato, and their colleagues specialize in, known as Chordodes, infect mantises and can grow to nearly 1 meter long inside the palm-size insects’ abdomens.

Keyword: Genes & Behavior; Evolution
Link ID: 28971 - Posted: 10.25.2023

By George Musser They call it the hard problem of consciousness, but a better term might be the impossible problem of consciousness. The whole point is that the qualitative aspects of our conscious experience, or “qualia,” are inexplicable. They slip through the explanatory framework of science, which is reductive: It explains things by breaking them down into parts and describing how they fit together. Subjective experience has an intrinsic je ne sais quoi that can’t be decomposed into parts or explained by relating one thing to another. Qualia can’t be grasped intellectually. They can only be experienced firsthand. For the past five years or so, I’ve been trying to untangle the cluster of theories that attempt to explain consciousness, traveling the world to interview neuroscientists, philosophers, artificial-intelligence researchers, and physicists—all of whom have something to say on the matter. Most duck the hard problem, either bracketing it until neuroscientists explain brain function more fully or accepting that consciousness has no deeper explanation and must be wired into the base level of reality. Although I made it a point to maintain an outsider’s view of science in my reporting, staying out of academic debates and finding value in every approach, I find both positions defensible but dispiriting. I cling to the intuition that consciousness must have some scientific explanation that we can achieve. But how? It’s hard to imagine how science could possibly expand its framework to accommodate the redness of red or the awfulness of fingernails on a chalkboard. But there is another option: to suppose that we are misconstruing our experience in some way. We think that it has intrinsic qualities, but maybe on closer inspection it doesn’t. Not that this is an easy position to take. Two leading theories of consciousness take a stab at it. Integrated Information Theory (IIT) says that the neural networks in our head are conscious since neurons act together in harmony—they form collective structures with properties beyond those of the individual cells. If so, subjective experience isn’t primitive and unanalyzable; in principle, you could follow the network’s transitions and read its mind. “What IIT tries to do is completely avoid any intrinsic quality in the traditional sense,” the father of IIT, Giulio Tononi, told me. © 2023 NautilusNext Inc.,

Keyword: Consciousness
Link ID: 28970 - Posted: 10.25.2023

By Mike Baker In a carpeted office suite, Alex Beck settled onto a mattress and, under the watch of a trained guide, began chomping through a handful of “Pumpkin Hillbilly” mushrooms. A Marine Corps veteran who was sexually assaulted during his time in the armed forces, Mr. Beck had long been searching unsuccessfully for a way to put those nightmarish years behind him. Now he was ready for a different kind of journey, a psychedelic trip through the nether regions of his own mind. As he felt his thoughts starting to spin, his “facilitator,” Josh Goldstein, urged him to surrender and let the mushrooms guide him. “It’s like the idea of planting a seed and then letting it go,” he said. Stigmatized in law and medicine for the past half-century, psychedelics are in the midst of a sudden revival, with a growing body of research suggesting that the mind-altering compounds could upend psychiatric care. Governments in several places have cautiously started to open access, and as Oregon voters approved a broad drug decriminalization plan in 2020, they also backed an initiative to allow the use of mushrooms as therapy. This summer, the state debuted a first-of-its-kind legal market for psilocybin mushrooms, more widely known as magic mushrooms. Far from the days of illicit consumption in basements and vans, the program allows people to embark on a therapeutic trip, purchasing mushrooms produced by a state-approved grower and consuming them in a licensed facility under the guidance of a certified facilitator. Mr. Beck, 30, was one of the first clients at a facility in the central Oregon city of Bend that began conducting sessions this summer in a building that on other days of the week offers chiropractic services. In his youth, Mr. Beck had experimented with psychedelics for recreation. But as he struggled with his lingering post-traumatic stress in adulthood, he learned about what seemed to be promising new research into plant-based psychedelics for mental health issues that did not respond to other treatments. He wondered if they could help him clear his head from the horrors of the past. © 2023 The New York Times Company

Keyword: Stress; Depression
Link ID: 28969 - Posted: 10.25.2023

Anil Oza Scientists once considered sleep to be like a shade getting drawn over a window between the brain and the outside world: when the shade is closed, the brain stops reacting to outside stimuli. A study published on 12 October in Nature Neuroscience1 suggests that there might be periods during sleep when that shade is partially open. Depending on what researchers said to them, participants in the study would either smile or frown on cue in certain phases of sleep. “You’re not supposed to be able to do stuff while you sleep,” says Delphine Oudiette, a cognitive scientist at the Paris Brain Institute in France and a co-author of the study. Historically, the definition of sleep is that consciousness of your environment halts, she adds. “It means you don’t react to the external world.” Dream time A few years ago, however, Oudiette began questioning this definition after she and her team conducted an experiment in which they were able to communicate with people who are aware that they are dreaming while they sleep — otherwise known as lucid dreamers. During these people’s dreams, experimenters were able to ask questions and get responses through eye and facial-muscle movements2. Karen Konkoly, who was a co-author on that study and a cognitive scientist at Northwestern University in Evanston, Illinois, says that after that paper came out, “it was a big open question in our minds whether communication would be possible with non-lucid dreamers”. So Oudiette continued with the work. In her latest study, she and her colleagues observed 27 people with narcolepsy — characterized by daytime sleepiness and a high frequency of lucid dreams — and 22 people without the condition. While they were sleeping, participants were repeatedly asked to frown or smile. All of them responded accurately to at least 70% of these prompts. © 2023 Springer Nature Limited

Keyword: Sleep; Learning & Memory
Link ID: 28968 - Posted: 10.25.2023

By Hope Reese There is no free will, according to Robert Sapolsky, a biologist and neurologist at Stanford University and a recipient of the MacArthur Foundation “genius” grant. Dr. Sapolsky worked for decades as a field primatologist before turning to neuroscience, and he has spent his career investigating behavior across the animal kingdom and writing about it in books including “Behave: The Biology of Humans at Our Best and Worst” and “Monkeyluv, and Other Essays on Our Lives as Animals.” In his latest book, “Determined: A Science of Life Without Free Will,” Dr. Sapolsky confronts and refutes the biological and philosophical arguments for free will. He contends that we are not free agents, but that biology, hormones, childhood and life circumstances coalesce to produce actions that we merely feel were ours to choose. It’s a provocative claim, he concedes, but he would be content if readers simply began to question the belief, which is embedded in our cultural conversation. Getting rid of free will “completely strikes at our sense of identity and autonomy and where we get meaning from,” Dr. Sapolsky said, and this makes the idea particularly hard to shake. There are major implications, he notes: Absent free will, no one should be held responsible for their behavior, good or bad. Dr. Sapolsky sees this as “liberating” for most people, for whom “life has been about being blamed and punished and deprived and ignored for things they have no control over.” He spoke in a series of interviews about the challenges that free will presents and how he stays motivated without it. These conversations were edited and condensed for clarity. To most people, free will means being in charge of our actions. What’s wrong with that outlook? It’s a completely useless definition. When most people think they’re discerning free will, what they mean is somebody intended to do what they did: Something has just happened; somebody pulled the trigger. They understood the consequences and knew that alternative behaviors were available. But that doesn’t remotely begin to touch it, because you’ve got to ask: Where did that intent come from? That’s what happened a minute before, in the years before, and everything in between. © 2023 The New York Times Company

Keyword: Consciousness; Attention
Link ID: 28967 - Posted: 10.17.2023

Max Kozlov Rich, high-fat foods such as ice cream are loved not only for their taste, but also for the physical sensations they produce in the mouth — their ‘mouthfeel’. Now scientists have identified a brain area that both responds to the smooth texture of fatty foods and uses that information to rate the morsel’s allure, guiding eating behaviour1. These findings, published on 16 October in The Journal of Neuroscience, “add a new dimension” of the eating experience to scientists’ understanding of what motivates people to choose certain foods, says Ivan de Araujo, a neuroscientist at the Max Planck Institute for Biological Cybernetics in Tübingen, Germany, who was not involved in the study. To explore how food textures influence eating habits, Fabian Grabenhorst, a neuroscientist at the University of Oxford, UK, and his colleagues set out to quantify the mouthfeel of fatty foods. The authors prepared several milkshakes with varying fat and sugar contents and placed a sample of each between two pig tongues procured from a local butcher. The researchers then slid the tongues across each other and measured the amount of friction between the two surfaces, providing a numerical index of each shake’s smoothness. The researchers then gave 22 participants milkshakes with the same compositions as those tested on the pig tongues. After tasting each milkshake, participants placed bids on how much they would spend to drink a full glass of it after the experiment. Accompanying brain scans showed that activity patterns in an area called the orbitofrontal cortex (OFC), which is involved in reward processing, reflected the shakes’ texture. The scans also identified OFC activity patterns that reflected participants’ bids, suggesting that this brain region links mouthfeel to the value placed on that food. © 2023 Springer Nature Limited

Keyword: Obesity; Chemical Senses (Smell & Taste)
Link ID: 28966 - Posted: 10.17.2023

By Matt Richtel An Oxford University researcher and her team showed that digital wearable devices can track the progression of Parkinson’s disease in an individual more effectively than human clinical observation can, according to a newly published paper. By tracking more than 100 metrics picked up by the devices, researchers were able to discern subtle changes in the movements of subjects with Parkinson’s, a neurodegenerative disease that afflicts 10 million people worldwide. The lead researcher emphasized that the latest findings were not a treatment for Parkinson’s. Rather, they are a means of helping scientists gauge whether novel drugs and other therapies for Parkinson’s are slowing the progression of the disease. Quotable Quotes The sensors — six per subject, worn on the chest, at the base of the spine and one on each wrist and foot — tracked 122 physiological metrics. Several dozen metrics stood out as closely indicating the disease’s progression, including the direction a toe moved during a step and the length and regularity of strides. “We have the biomarker,” said Chrystalina Antoniades, a neuroscientist at the University of Oxford and the lead researcher on the paper, which was published earlier this month in the journal npj Parkinson’s Disease. “It’s super exciting. Now we hope to be able to tell you: Is a drug working?” Until now, Dr. Antoniades said, drug trials for Parkinson’s had relied on clinical assessment of whether a treatment was slowing the progression of the disease. But clinical observation can miss changes that happen day to day or that might not show up clearly in periodic visits to a doctor, she added. In the paper, the study’s authors concluded that the sensors proved more effective at tracking the disease progression “than the conventionally used clinical rating scales.” © 2023 The New York Times Company

Keyword: Parkinsons
Link ID: 28965 - Posted: 10.17.2023

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

Keyword: Sleep
Link ID: 28964 - Posted: 10.17.2023

By Carl Zimmer An international team of scientists has mapped the human brain in much finer resolution than ever before. The brain atlas, a $375 million effort started in 2017, has identified more than 3,300 types of brain cells, an order of magnitude more than was previously reported. The researchers have only a dim notion of what the newly discovered cells do. The results were described in 21 papers published on Thursday in Science and several other journals. Ed Lein, a neuroscientist at the Allen Institute for Brain Science in Seattle who led five of the studies, said that the findings were made possible by new technologies that allowed the researchers to probe millions of human brain cells collected from biopsied tissue or cadavers. “It really shows what can be done now,” Dr. Lein said. “It opens up a whole new era of human neuroscience.” Still, Dr. Lein said that the atlas was just a first draft. He and his colleagues have only sampled a tiny fraction of the 170 billion cells estimated to make up the human brain, and future surveys will certainly uncover more cell types, he said. Biologists first noticed in the 1800s that the brain was made up of different kinds of cells. In the 1830s, the Czech scientist Jan Purkinje discovered that some brain cells had remarkably dense explosions of branches. Purkinje cells, as they are now known, are essential for fine-tuning our muscle movements. Later generations developed techniques to make other cell types visible under a microscope. In the retina, for instance, researchers found cylindrical “cone cells” that capture light. By the early 2000s, researchers had found more than 60 types of neurons in the retina alone. They were left to wonder just how many kinds of cells were lurking in the deeper recesses of the brain, which are far harder to study. © 2023 The New York Times Company

Keyword: Brain imaging; Development of the Brain
Link ID: 28963 - Posted: 10.14.2023