Will Stone Maybe this happens to you sometimes, too: You go to bed with some morning obligation on your mind, maybe a flight to catch or an important meeting. The next morning, you wake up on your own and discover you've beat your alarm clock by just a minute or two. What's going on here? Is it pure luck? Or perhaps you possess some uncanny ability to wake up precisely on time without help? It turns out many people have come to Dr. Robert Stickgold over the years wondering about this phenomenon. "This is one of those questions in the study of sleep where everybody in the field seems to agree that's what's obviously true couldn't be," says Stickgold who's a cognitive neuroscientist at Harvard Medical School and Beth Israel Deaconess Medical Center. Stickgold even remembers bringing it up to his mentor when he was just starting out in the field — only to be greeted with a dubious look and a far from satisfactory explanation. "I can assure you that all of us sleep researchers say 'balderdash, that's impossible,' " he says. And yet Stickgold still believes there is something to it. "This kind of precision waking is reported by hundreds and thousands of people,'" he says, including himself. "I can wake up at 7:59 and turn off the alarm clock before my wife wakes up." At least, sometimes. Of course, it's well known that humans have an elegant and intricate system of internal processes that help our bodies keep time. Somewhat shaped by our exposure to sunlight, caffeine, meals, exercise and other factors, these processes regulate our circadian rhythms throughout the roughly 24-hour cycle of day and night, and this affects when we go to bed and wake up. © 2022 npr

Keyword: Biological Rhythms
Link ID: 28614 - Posted: 12.28.2022

By Kelsey Ables Persistent loss of smell has left some covid-19 survivors yearning for the scent of their freshly bathed child or a waft of their once-favorite meal. It’s left others inured to the stink of garbage and accidentally drinking spoiled milk. “Anosmia,” as experts call it, is one of long covid’s strangest symptoms — and researchers may be one step closer to figuring it out what causes it and how to fix it. A small study published online on Wednesday in Science Translational Medicine and led by researchers at Duke University, Harvard and the University of California San Diego offers a theory, and new insight, into lingering smell loss. Scientists analyzed samples of olfactory epithelial tissue — where smell cells live — from 24 biopsies, nine of which were from post-covid patients struggling with persistent loss of smell. Although the sample was small, the results suggest that the sensory deficit is linked to an ongoing immune attack on cells responsible for smell — which endures even after the virus is gone — and a decline in the number of olfactory nerve cells. Bradley Goldstein, associate professor in Duke’s Department of Head and Neck Surgery and Communication Sciences and the Department of Neurobiology, an author on the paper, called the results “striking” and said in a statement, “It’s almost resembling a sort of autoimmune-like process in the nose.” While there has been research that looks at short-term smell loss and uses animal models, the new study is notable because it focuses on persistent smell loss and uses high-tech molecular analysis on human tissue. The study reflects enduring interest in the mysterious symptom. In July, researchers estimated that at least 5.6 percent of covid-19 patients develop chronic smell problems. That study, published in the peer-reviewed medical trade publication BMJ, also suggested that women as well as those who had more severe initial dysfunction were less likely to recover their sense of smell. Seniors are also especially vulnerable, The Post has reported.

Keyword: Chemical Senses (Smell & Taste)
Link ID: 28613 - Posted: 12.28.2022

By Shayla Love On Valentine’s Day in 2016, Anne Lantoine received not flowers, but divorce papers. In the months preceding, she had been preparing for her family’s move from France to Canada—or so she thought. She arrived in Quebec early with one of her three children, who was preparing to start college there, while the other two remained in Europe for school. Her husband stayed behind to manage the sale of their house in Marseille. Then the realtors began to complain, through a barrage of calls and emails, to Lantoine. Her husband was not acting like a man who wanted his house sold. He wasn’t answering phone calls and was never available for showings. In January 2016, Lantoine called him after yet another complaint from a realtor. The next morning, he sent her an email with a notice for a court hearing, and she discovered her husband had actually filed for divorce, without telling her, months earlier. That February, she finally got the paperwork, not from her husband, but from her real estate agent. “It was not my last shock,” Lantoine, now 59, recalls. “I also discovered that my husband’s mistress was living in my home.” These revelations were a huge blow practically: It disrupted the immigration paperwork, and Lantoine and her daughter lost their visa applications. But the searing pain was in the betrayal and deceit. “I became very anxious and had constant nightmares,” she says. “I was tired all the time and had panic attacks each time I opened my mail or my emails, or when I had an unidentified phone call.” Though the details of each case vary, romantic betrayal through infidelity, abandonment, or emotional manipulation can upend one’s life in an instant. For Lantoine, her future plans, and the person they were attached to, were suddenly gone, and her functioning along with them. © 2022 NautilusThink Inc, All rights reserved.

Keyword: Stress; Learning & Memory
Link ID: 28612 - Posted: 12.28.2022

By Deborah Blum Back in the year 2000, sitting in his small home office in California’s Mill Valley, surrounded by stacks of spreadsheets, Jay Rosner hit one of those dizzying moments of dismay. An attorney and the executive director of The Princeton Review Foundation, the philanthropic arm of the private test-preparation and tutoring company, The Princeton Review, Rosner was scheduled to give testimony in a highly charged affirmative action lawsuit against the University of Michigan. He knew the case, Grutter v. Bollinger, was eventually headed to the U.S. Supreme Court, but as he reviewed the paperwork, he discovered a daunting gap in his argument.  Rosner had been asked to explore potential racial and cultural biases baked into standardized testing. He believed such biases, which critics had been surfacing for years prior, were real, but in that moment, he felt himself coming up short. “I suddenly realized that I would be deposed on this issue,” he recalled, “and I had no data to support my hypothesis, only deductive reasoning.”   The punch of that realization still resonates. Rosner is the kind of guy who really likes data to stand behind his points, and he recalls an anxiety-infused hunt for some solid facts. Rosner was testifying about an entrance exam for law school, the LSAT, for which he could find no particulars. But he knew that a colleague had data on how students of different racial backgrounds answered specific questions on another powerful standardized test, the SAT, long used to help decide undergraduate admission to colleges — given in New York state. He decided he could use that information to make a case by analogy. The two scholars agreed to crunch some numbers.  Based on past history of test results, he knew that White students would overall have higher scores than Black students. Still, Rosner expected Black students to perform better on some questions. To his shock, he found no trace of such balance. The results were “incredibly uniform,” he said, skewing almost entirely in favor of White students. “Every single question except one in the New York state data on four SATs favored Whites over Blacks,” Rosner recalled.

Keyword: Intelligence; Genes & Behavior
Link ID: 28611 - Posted: 12.24.2022

By Susan Milius As tiny glass frogs fall asleep for the day, they take almost 90 percent of their red blood cells out of circulation. The colorful cells cram into hideaway pockets inside the frog liver, which disguises the cells behind a mirrorlike surface, a new study finds. Biologists have known that glass frogs have translucent skin, but temporarily hiding bold red blood brings a new twist to vertebrate camouflage (SN: 6/23/17). “The heart stopped pumping red, which is the normal color of blood, and only pumped a bluish liquid,” says evolutionary biochemist Carlos Taboada of Duke University, one of the discoverers of the hidden blood. What may be even more amazing to humans — prone to circulatory sludge and clogs — is that the frogs hold almost all their red blood cells packed together for hours with no blood clots, says co-discoverer Jesse Delia, now at the American Museum of Natural History in New York City. Wake the frog up, and cells just unpack themselves and get circulating again. Hiding those red blood cells can double or triple the transparency of glass frogs, Taboada, Delia and colleagues report in the Dec. 23 Science. That greenish transparency can matter a lot for the snack-sized frogs, which spend the day hiding like little shadows on the undersides of the leaves high in the forest canopy. A photo on the left showing a sleeping female glass frog with most of her red blood cells tucked into her liver. While the photo on the right shows the frog while awake with blood circulating and less transparent. What got Delia wondering about transparency was a photo emergency. He had studied glass frog behavior, but had never even seen them asleep. “They go to bed, I go to bed — that was my life for years,” he says. When he needed some charismatic portraits, however, he put some frogs in lab dishes and at last saw how the animals sleep the day away. © Society for Science & the Public 2000–2022.

Keyword: Sleep; Aggression
Link ID: 28610 - Posted: 12.24.2022

By Tom Siegfried Survival of the fittest often means survival of the fastest. But fastest doesn’t necessarily mean the fastest moving. It might mean the fastest thinking. When faced with the approach of a powerful predator, for instance, a quick brain can be just as important as quick feet. After all, it is the brain that tells the feet what to do — when to move, in what direction, how fast and for how long. And various additional mental acrobatics are needed to evade an attacker and avoid being eaten. A would-be meal’s brain must decide whether to run or freeze, outrun or outwit, whether to keep going or find a place to hide. It also helps if the brain remembers where the best hiding spots are and recalls past encounters with similar predators. All in all, a complex network of brain circuitry must be engaged, and neural commands executed efficiently, to avert a predatory threat. And scientists have spent a lot of mental effort themselves trying to figure out how the brains of prey enact their successful escape strategies. Studies in animals as diverse as mice and crabs, fruit flies and cockroaches are discovering the complex neural activity — in both the primitive parts of the brain and in more cognitively advanced regions — that underlies the physical behavior guiding escape from danger and the search for safety. Lessons learned from such studies might not only illuminate the neurobiology of escape, but also provide insights into how evolution has shaped other brain-controlled behaviors. This research “highlights an aspect of neuroscience that is really gaining traction these days,” says Gina G. Turrigiano of Brandeis University, past president of the Society for Neuroscience. “And that is the idea of using ethological behaviors — behaviors that really matter for the biology of the animal that’s being studied — to unravel brain function.” © 2022 Annual Reviews

Keyword: Aggression; Attention
Link ID: 28609 - Posted: 12.24.2022

Jon Hamilton Time is woven into our personal memories. Recall a childhood fall from a bike and the brain replays the entire episode in excruciating detail: the glimpse of wet leaves on the road ahead, the moment of weightless dread, and then the painful impact. This exact sequence has been embedded in the memory, thanks to some special neurons known as time cells. When the brain detects a notable event, time cells begin a highly orchestrated performance, says Marc Howard, who directs the Brain, Behavior, and Cognition program at Boston University. "What we find is that the cells fire in a sequence," he says. "So cell one might fire immediately, but cell two waits a little bit, followed by cell three, cell four, and so on." As each cell fires, it places a sort of time stamp on an unfolding experience. And the same cells fire in the same order when we retrieve a memory of the experience, even something mundane. "If I remember being in my kitchen and making a cup of coffee," Howard says, "the time cells that were active at that moment are re-activated." They recreate the grinder's growl, the scent of Arabica, the curl of steam rising from a fresh mug – and your neurons replay these moments in sequence every time you summon the memory. This system appears to explain how we are able to virtually travel back in time, and play mental movies of our life experiences. There are also hints that time cells play a critical role in imagining future events. Without time cells, our memories would lack order. In an experiment at the University of California, San Diego, scientists gave several groups of people a tour of the campus. The tour included 11 planned events, including finding change in a vending machine and drinking from a water fountain. © 2022 npr

Keyword: Attention; Learning & Memory
Link ID: 28608 - Posted: 12.21.2022

By Yan Zhuang Delirium. Fever. Hallucinations. Not what you expect when adding baby spinach to a salad, but these are among the alarming symptoms dozens of Australians have experienced after consuming what are thought to be contaminated batches of the leafy greens. More than 100 people reported symptoms, including at least 54 who have sought medical help, after eating baby spinach that the authorities believe to be tainted. Four major supermarket chains have recalled products containing the suspect spinach. The authorities said that the spinach had caused “possible food-related toxic reactions” with those affected experiencing symptoms including delirium, hallucinations, blurred vision, rapid heartbeat and fever. Some Australians took to social media to jokingly ask how they could obtain hallucinogenic spinach. “Never have I been so interested in salad,” one Twitter user said. But the authorities have stressed that the symptoms are far from pleasant. “They’re unable to see properly, they’re confused, they’re having hallucinations,” Darren Roberts, the medical director of New South Wales’s Poisons Information Center, said of the victims in an interview on local television. “And we’re talking about scary hallucinations; it’s nothing that’s fun.” Its producer, Riviera Farms in the state of Victoria, said it believed its product had been “contaminated with a weed.” What weed could make spinach hallucinogenic? The health department of the state of Victoria has said that the symptoms suggested “anticholinergic syndrome,” a type of poisoning mainly caused by plants in the Solanaceae family, which includes nightshade, jimson weed and mandrake root. Anticholinergic plants and drugs inhibit the production of a brain chemical called acetylcholine, which is linked to memory, thinking and the visual system, according to Dominic ffytche, a professor of visual psychiatry at King’s College London, who specializes in visual hallucinations (and who really does lowercase his last name). Acetylcholine can also be lost naturally and is linked to Alzheimer’s, some type of dementias and other neurodegenerative diseases, he said. © 2022 The New York Times Company

Keyword: Drug Abuse
Link ID: 28607 - Posted: 12.21.2022

By Laurie McGinley and  Lenny Bernstein Rachel Graham has battled excess weight for years, cycling through trendy diets, various drugs, even bariatric surgery. Nothing worked for long. But last summer, she started a new medication, and today is 40 pounds lighter — and still shedding weight. “It used to be that if I saw food, I would want to eat it,” said the 54-year-old Graham, who is 5-foot-7 and 190 pounds. “Now, if I have three or four bites of food, I don’t want to eat more.” The drug she’s taking, Mounjaro by Eli Lilly, is part of a new crop of therapies that experts are hailing as a medical milestone — a long-sought way to transform the treatment of obesity, one of the nation’s most serious health threats. Designed for diabetes but used for obesity at higher doses, the medications induce loss of 15 to 22 percent of body weight on average — more than enough to significantly reduce cardiovascular and other health risks. That makes them far superior to old-style diet pills that delivered smaller benefits along with nasty side effects such as high blood pressure and loose stools. But during the past year, soaring demand for the drugs has ignited a mad scramble, exposing some of the most persistent problems in the nation’s health-care system, including supply shortages, high costs and health-care inequities. Tensions are surging as patients with diabetes and those with weight problems sometimes compete for the same medications, which are self-administered in weekly injections. Some doctors worry that the drugs, which might have to be taken for life, will overshadow the need for lifestyle changes involving diet and exercise.

Keyword: Obesity
Link ID: 28606 - Posted: 12.21.2022

By Anthea Rowan To many, the word “hobby” signifies something lightweight or trivial. Yet taking on a new hobby as one ages might provide an important defense against dementia, some experts say. About 5.8 million adults over 65 in the United States live with Alzheimer’s disease or other dementia disorders, according to the Centers for Disease Control and Prevention. One in 9 Americans over 65 has Alzheimer’s, according to the Alzheimer’s Association. And although the rate of dementia may be falling thanks to lifestyle changes, more of us are living longer, which means the societal burden of dementia is rising. David Merrill, an adult and geriatric psychiatrist and director of the Pacific Brain Health Center in Santa Monica, Calif., suggests we use the word “pursuit” instead of “hobby,” as it elevates the concept of an activity to something demanding, something requiring concentration or collaboration. Something we ought to chase down. Activities that demand focus and industry are the whetstone to keeping cognition sharp, Merrill says. Our brains, he continues, are like any other part of our body. “‘Use it or lose it’ is not just a hypothesis, it’s a basic biologic fact that holds as true for our brains as our muscles or our bones.” While there is as yet no surefire way to prevent dementia or cure it, the Lancet in 2020 identified 12 potentially modifiable risk factors for the condition; they include physiological (blood pressure, diabetes, hearing loss), lifestyle choices (smoking, drinking, physical inactivity), environmental (air pollution) depression, social isolation and a lower level of education. The Alzheimer Society of Canada is also clear about what we can do to help minimize our dementia risk: keep cognitively engaged, learn new things, meet new people, keep a diary, remain curious and engage in conversations.

Keyword: Alzheimers; Learning & Memory
Link ID: 28605 - Posted: 12.21.2022

Patrick Barkham Three species of cetacean stranded off the coast of Scotland, including a bottlenose dolphin and a long-finned pilot whale, have been found to have the classic markers of Alzheimer’s disease, according to a study. Although types of dementia have been fairly widely detected in other animals, Alzheimer’s disease has not been found to occur naturally in species other than humans. But researchers from the University of Glasgow, the universities of St Andrews and Edinburgh and the Moredun Research Institute in Scotland were surprised to find that postmortem tests of 22 toothed whales, or odontocetes, detected three key brain changes associated with human Alzheimer’s disease in three animals. Scientists do not know the cause of this brain degeneration but it could support one theory about why some groups or pods of whales and dolphins run aground in shallow water. Some mass strandings have been linked to increasing anthropogenic noise in the oceans, but Alzheimer’s-like signs in the brain could support a “sick leader” theory, whereby mostly healthy cetaceans are stranded because they follow a group leader that has become confused or lost. The researchers found signs of Alzheimer’s in three of 22 stranded odontocetes: a white-beaked dolphin, a bottlenose dolphin and a long-finned pilot whale, also a member of the dolphin family.

Keyword: Alzheimers
Link ID: 28604 - Posted: 12.21.2022

By Sandra G. Boodman The 23-year-old patient arrived in the back of a police car and was in four point restraints — hands and feet strapped to a gurney — when emergency physician Elizabeth Mitchell saw her at a Los Angeles hospital early on March 17. Chloe R. Kral was being held on a 5150, shorthand in California for an emergency psychiatric order that allows people deemed dangerous to themselves or others to be involuntarily confined for 72 hours. She had spent the previous six months at a private treatment center receiving care for bipolar disorder and depression. Chloe had improved and was set to move to transitional housing when she suddenly became combative and threatened to harm staff and kill herself. Police had taken her to the emergency room at Cedars-Sinai Marina del Rey Hospital before a planned transfer to a mental hospital. Chloe, Mitchell recalled, was “mumbling about Rosa Parks” when they met. She managed to tell the doctor that she hadn’t used drugs or alcohol, but was otherwise incoherent. “We get a lot of psychiatric patients, and they’re just waiting for placement,” Mitchell said. But something indefinable — Mitchell characterized it as “maybe gut instinct” honed by nearly two decades of practice — prompted her to order a CT scan of Chloe’s head to better assess her mental status. When she pulled up the image, Mitchell gasped. “I had never seen anything like it,” she said. She rounded up her colleagues and “made everyone in the whole ER come look.” “I was speechless,” she said. “All I could think was ‘How did no one figure this out?’ ”

Keyword: Depression; Schizophrenia
Link ID: 28603 - Posted: 12.21.2022

By Claudia López Lloreda Learning lots of new information as a baby requires a pool of ready-to-go, immature connections between nerve cells to form memories quickly. Called silent synapses, these connections are inactive until summoned to help create memories, and were thought to be present mainly in the developing brain and die off with time. But a new study reveals that there are many silent synapses in the adult mouse brain, researchers report November 30 in Nature. Neuroscientists have long puzzled over how the adult human brain can have stable, long-term memories, while at the same time maintaining a certain flexibility to be able to make new memories, a concept known as plasticity (SN: 7/27/12). These silent synapses may be part of the answer, says Jesper Sjöström, a neuroscientist at McGill University in Montreal who was not involved with the study. “The silent synapses are ready to hook up,” he says, possibly making it easier to store new memories as an adult by using these connections instead of having to override or destabilize mature synapses already connected to memories. “That means that there’s much more room for plasticity in the mature brain than we previously thought.” In a previous study, neuroscientist Mark Harnett of MIT and his colleagues had spotted many long, rod-shaped structures called filopodia in adult mouse brains. That surprised Harnett because these protrusions are mostly found on nerve cells in the developing brain. “Here they were in adult animals, and we could see them crystal clearly,” Harnett says. So he and his team decided to examine the filopodia to see what role they play, and if they were possibly silent synapses. The researchers used a technique to expand the brains of adult mice combined with high-resolution microscopy. Since nerve cell connections and the molecules called receptors that allow for communication between connected cells are so small, these methods revealed synapses that past research missed. © Society for Science & the Public 2000–2022.

Keyword: Learning & Memory
Link ID: 28602 - Posted: 12.17.2022

By Gary Stix  Can the human brain ever really understand itself? The problem of gaining a deep knowledge of the subjective depths of the conscious mind is such a hard problem that it has in fact been named the hard problem. The human brain is impressively powerful. Its 100 billion neurons are connected by 100 trillion wirelike fibers, all squeezed into three pounds of squishy flesh lodged below a helmet of skull. Yet we still don’t know whether this organ will ever be able to muster the requisite smarts to hack the physical processes that underlie the ineffable “quality of deep blue” or “the sensation of middle C,” as philosopher David Chalmers put it when giving examples of the “hard problem” of consciousness, a term he invented, in a 1995 paper. This past year did not uncover a solution to the hard problem, and one may not be forthcoming for decades, if ever. But 2022 did witness plenty of surprises and solutions to understanding the brain that do not require a complete explanation of consciousness. Such incrementalism could be seen in mid-November, when a crowd of more than 24,000 attendees of the annual Society for Neuroscience meeting gathered in San Diego, Calif. The event was a tribute of sorts to reductionism—the breaking down of hard problems into simpler knowable entities. At the event, there were reports of an animal study of a brain circuit that encodes social trauma and a brain-computer interface that lets a severely paralyzed person mentally spell out letters to form words. Your Brain Has a Thumbs-Up–Thumbs-Down Switch When neuroscientist Kay Tye was pursuing her Ph.D., she was told a chapter on emotion was inappropriate for her thesis. Emotion just wasn’t accepted as an integral, intrinsic part of behavioral neuroscience, her field of study. That didn’t make any sense to Tye. She decided to go her own way to become a leading researcher on feelings. This year Tye co-authored a Nature paper that reported on a kind of molecular switch in rodents that flags an experience as either good or bad. If human brains operate the same way as the brains of the mice in her lab, a malfunctioning thumbs-up–thumbs-down switch might explain some cases of depression, anxiety and addiction.

Keyword: Consciousness
Link ID: 28601 - Posted: 12.17.2022

By Susan Coll Last summer, my husband had gone hiking with our two dogs when one of them — a year-old rescue who weighs in at over 50 pounds, can scale steep inclines like a mountain goat and has the speed and grace of an Olympic athlete — suddenly collapsed. Unable to stand, Dafna was disoriented and had also become incontinent. Was it a seizure? A stroke? A snake bite? We piled into our car and headed to an emergency veterinary clinic. I held Dafna’s head in my lap, convinced the end was near. This puppy had destroyed two pairs of my prescription eyeglasses, a new leather wallet, and had torn gashes in my clothes. She’d chewed through my daughter’s internet cords. Still, I loved her like no other. At the clinic, the staff rushed Dafna to a back room with the professionalism expected in a life-or-death situation. But we thought we also noticed a hint of amusement? Even a smirk? A few moments later, we learned why. The vet explained that while they were running a urine test to confirm their suspicions, they were pretty sure Dafna had ingested THC, maybe from a marijuana plant growing wild along the trail, or perhaps she’d eaten a discarded pot roach. Basically, our dog was stoned. It turns out that’s not so unusual these days. In Vermont, where we were and where possession and use of marijuana was legalized in 2018, the vet said she now sees as many as 10 cases per week of pot intoxication. According to ASPCApro and local vets, that’s happening across the country. © 1996-2022 The Washington Post

Keyword: Drug Abuse
Link ID: 28599 - Posted: 12.17.2022

Ari Daniel Fred Crittenden, 73, lost his sight to retinitis pigmentosa when he was 35 years old. Today he has no visual perception of light. "It's total darkness," he says. Still, he has cells in his eyes that use light to keep his internal clock ticking along nicely. Marta Iwanek for NPR Every baseball season, 73-year-old Fred Crittenden plants himself in front of his television in his small one-bedroom apartment an hour north of Toronto. "Oh, I love my sports — I love my Blue Jays," says Crittenden. "They need me to coach 'em — they'd be winning, I'll tell ya." He listens to the games in his apartment. He doesn't watch them, because he can't see. "I went blind," Crittenden recalls, when "I was 35 years young." Crittenden has retinitis pigmentosa, an inherited condition that led to the deterioration of his retinas. He lost all his rods (the cells that help us see in dim light) and all his cones (the cells that let us see color in brighter light). Within a single year, in 1985, Crittenden says he went from perfect vision to total blindness. Certain cells within Crittenden's retinas that contain melanopsin help his brain to detect light, even if what he sees is darkness. Among other things, these light-detecting cells help his body regulate his sleep cycles. Marta Iwanek for NPR "The last thing I saw clearly," he says, thinking back, "it was my daughter, Sarah. She was 5 years old then. I used to go in at night and just look at her when she was in the crib. And I could just barely still make her out — her little eyes or her nose or her lips or her chin, that kind of stuff. Even to this day it's hard." © 2022 npr

Keyword: Biological Rhythms; Vision
Link ID: 28598 - Posted: 12.17.2022

By Yasemin Saplakoglu Memory and perception seem like entirely distinct experiences, and neuroscientists used to be confident that the brain produced them differently, too. But in the 1990s neuroimaging studies revealed that parts of the brain that were thought to be active only during sensory perception are also active during the recall of memories. “It started to raise the question of whether a memory representation is actually different from a perceptual representation at all,” said Sam Ling, an associate professor of neuroscience and director of the Visual Neuroscience Lab at Boston University. Could our memory of a beautiful forest glade, for example, be just a re-creation of the neural activity that previously enabled us to see it? “The argument has swung from being this debate over whether there’s even any involvement of sensory cortices to saying ‘Oh, wait a minute, is there any difference?’” said Christopher Baker, an investigator at the National Institute of Mental Health who runs the learning and plasticity unit. “The pendulum has swung from one side to the other, but it’s swung too far.” Even if there is a very strong neurological similarity between memories and experiences, we know that they can’t be exactly the same. “People don’t get confused between them,” said Serra Favila, a postdoctoral scientist at Columbia University and the lead author of a recent Nature Communications study. Her team’s work has identified at least one of the ways in which memories and perceptions of images are assembled differently at the neurological level. When we look at the world, visual information about it streams through the photoreceptors of the retina and into the visual cortex, where it is processed sequentially in different groups of neurons. Each group adds new levels of complexity to the image: Simple dots of light turn into lines and edges, then contours, then shapes, then complete scenes that embody what we’re seeing. Simons Foundation © 2022

Keyword: Attention; Vision
Link ID: 28597 - Posted: 12.15.2022

ByElizabeth Pennisi Willpower might be key to getting off the couch to exercise, but bacteria may lend a helping hand. Studies in mice reported today in Nature suggest microbes in the gut may be behind differences in the desire to work out. A research team has homed in on specific microbial molecules that stimulate a rodent’s desire to run—and keep running. By revealing exactly how these molecules talk to the brain, this group has set the stage for finding out whether similar signals help keep humans active. The work “establishes just how critical the microbiome is for exercise and goes incredibly deep in providing a new gut-brain [connection],” says Aleksandar Kostic, a microbiologist at Harvard Medical School who is co-founder of FitBiomics, a company developing probiotics to improve fitness. Kostic, who wasn’t involved in the research, and others speculate that exercise-inducing commands from the microbes might one day be packaged into pills people could take. To explore why some people like to exercise and others don’t, University of Pennsylvania microbiologist Christoph Thaiss studied mice bred to have a lot of genetic and behavioral variation. His team found more than a fivefold difference in how far the mice ran on wheels in their cages—some covered more than 30 kilometers in 48 hours, whereas others rarely moved in their wheels. The active and lazy mice didn’t show any significant differences in their genetics or biochemistry. But the researchers did notice one clue: When treated with antibiotics, mice that were normally highly energetic tended to exercise less. Follow-up studies showed the antibiotic treatment affected the brains of the formerly active mice. The activity of certain brain genes declined, along with levels of dopamine, a neurotransmitter that has been linked to “runner’s high”—that sense of wellbeing that comes with prolonged exercise.

Keyword: Obesity
Link ID: 28596 - Posted: 12.15.2022

By Yasemin Saplakoglu It’s often subtle at first. A lost phone. A forgotten word. A missed appointment. By the time a person walks into a doctor’s office, worried about signs of forgetfulness or failing cognition, the changes to their brain have been long underway — changes that we don’t yet know how to stop or reverse. Alzheimer’s disease, the most common form of dementia, has no cure. “There’s not much you can do. There are no effective treatments. There’s no medicine,” said Riddhi Patira, a behavioral neurologist in Pennsylvania who specializes in neurodegenerative diseases. That’s not how the story was supposed to go. Three decades ago, scientists thought they had cracked the medical mystery of what causes Alzheimer’s disease with an idea known as the amyloid cascade hypothesis. It accused a protein called amyloid-beta of forming sticky, toxic plaques between neurons, killing them and triggering a series of events that made the brain waste away. The amyloid cascade hypothesis was simple and “seductively compelling,” said Scott Small, the director of the Alzheimer’s Disease Research Center at Columbia University. And the idea of aiming drugs at the amyloid plaques to stop or prevent the progression of the disease took the field by storm. Decades of work and billions of dollars went into funding clinical trials of dozens of drug compounds that targeted amyloid plaques. Yet almost none of the trials showed meaningful benefits to patients with the disease. That is, until September, when the pharmaceutical giants Biogen and Eisai announced that in a phase 3 clinical trial, patients taking the anti-amyloid drug lecanemab showed 27% less decline in their cognitive health than patients taking a placebo did. Last week, the companies revealed the data, now published in the New England Journal of Medicine, to an excited audience at a meeting in San Francisco. Simons Foundation © 2022

Keyword: Alzheimers
Link ID: 28595 - Posted: 12.15.2022

By Jake Buehler Female snakes have clitorises too, a new study finds. The research raises the possibility that the sex lives of snakes are more complicated and diverse than previously understood, researchers report December 14 in Proceedings of the Royal Society B. Clitorises are found in a wide range of vertebrate life, from crocodiles to dolphins (SN: 1/10/22). One exception is birds, which lost their clitorises over the course of their evolution. Female snakes appeared to have lost the sex organ too, which was puzzling, since their close lizard relatives possess paired clitorises, called hemiclitorises. Male lizards and snakes have accompanying paired phalli, or hemipenises.  This element of female snakes’ sexual anatomy went unexamined in detail for so long partly because hemiclitorises can be fragile and easy to miss, but also because female genitalia have historically been considered “quite taboo,” says evolutionary biologist Megan Folwell of the University of Adelaide in Australia. “Even in humans, the proper function and significance of the human clitoris was still being discussed in 2006,” she says. Conflicting accounts of snake hemiclitorises in some scientific papers led Folwell to take a detailed look. She first examined a euthanized female common death adder (Acanthophis antarcticus). “I just started with dissecting the tail and going into it with a really open mind of what I might find,” she says. She was “pleasantly surprised” to find dual organs within that were completely different from the hemipenises found in male snakes. Also, unlike lizard hemiclitorises, the snake’s couldn’t turn out externally. © Society for Science & the Public 2000–2022.

Keyword: Sexual Behavior; Evolution
Link ID: 28594 - Posted: 12.15.2022