Most Recent Links

Follow us on Facebook or subscribe to our mailing list, to receive news updates. Learn more.


Links 1 - 20 of 27828

By Sara Goudarzi Life isn’t always easy for little mouse pups: Hours to days after they are born, the squirmy babies, who can’t hear or see, can roll or stumble away from their nest. Cold and lonely, they call out to their mother. Luckily, Mom snaps into action to ensure the adventures of the little ones are short-lived. Grabbing each pup by the skin on their backs, Mama mouse brings each baby back home to safety. The mom’s behavior is innate, burnt into the mouse brain, and requires no training. But where in the brain does it happen and how does the brain process or execute it? And what happens in those rare cases when the animal brain doesn’t properly execute such behavior? That’s what Stephen Shea is trying to answer in mice, with hopes that it may someday be applicable to humans. Shea, an associate professor at Cold Spring Harbor Laboratory, discovered that this innate mothering behavior corresponds to the firing of cells in a region of the brain called locus coeruleus, a cluster of cells that can be found in the brainstem of all vertebrates. Locus coeruleus is also the source of noradrenaline, a chemical that affects some key brain functions. Shea’s work has greater implications. He hopes that understanding the brain circuits that facilitate this very simple action could be a window into how disruptions in wiring affect social behavior, and a key into understanding inappropriate social interactions, such as those observed in people with autism spectrum disorders. And it may even shed some light on the iconic debate about whether creatures are shaped by nature or nurture. © 2022 NautilusThink Inc,

Keyword: Sexual Behavior
Link ID: 28424 - Posted: 08.06.2022

Martha Bebinger Approaching a van that distributes safe supplies for drug use in Greenfield, Mass., a man named Kyle noticed an alert about xylazine. "Xylazine?" he asked, sounding out the unfamiliar word. "Tell me more." A street-outreach team from Tapestry Health delivered what's becoming a routine warning. Xylazine is an animal tranquilizer. It's not approved for humans, but it's showing up in about half of the drug samples that Tapestry tests in the rolling hills of western Massachusetts. It's appearing mostly in the illegal fentanyl supply but also in cocaine. Kyle rocked backward on his heels at the mention of cocaine. He and his friends regularly use cocaine, but lately, they had suspected that something else was in the bag. "The past week, we've all been just racking our brains, like 'What is going on?'" he said. "Because if we cook it up and we smoke it, we're falling asleep after." Kyle's deep sleep might have been triggered by fentanyl too, but Kyle said one of his buddies used a test strip to check for the opioid and none was detected. Xylazine surged first in some areas of Puerto Rico and then in Philadelphia, where it was found in 91% of opioid samples last year, the most recent reporting period. Data from January to mid-June shows that xylazine was in 28% of drug samples tested by the Massachusetts Drug Supply Data Stream (MADDS), a state-funded network of community drug-checking and advisory groups that uses mass spectrometers to let people know what's in bags or pills purchased on the street. Some areas of the state, including western Massachusetts, are seeing xylazine in 50% to 75% of samples. In Greenfield, that's a big change from last year, when xylazine wasn't a concern. © 2022 npr

Keyword: Drug Abuse
Link ID: 28423 - Posted: 08.06.2022

By Siobhan Roberts In June, 100 fruit fly scientists gathered on the Greek island of Crete for their biennial meeting. Among them was Cassandra Extavour, a Canadian geneticist at Harvard University. Her lab works with fruit flies to study evolution and development — “evo devo.” Most often, such scientists choose as their “model organism” the species Drosophila melanogaster — a winged workhorse that has served as an insect collaborator on at least a few Nobel Prizes in physiology and medicine. But Dr. Extavour is also known for cultivating alternative species as model organisms. She is especially keen on the cricket, particularly Gryllus bimaculatus, the two-spotted field cricket, even though it does not yet enjoy anything near the fruit fly’s following. (Some 250 principal investigators had applied to attend the meeting in Crete.) “It’s crazy,” she said during a video interview from her hotel room, as she swatted away a beetle. “If we tried to have a meeting with all the heads of labs working on that cricket species, there might be five of us, or 10.” Crickets have already been enlisted in studies on circadian clocks, limb regeneration, learning, memory; they have served as disease models and pharmaceutical factories. Veritable polymaths, crickets! They are also increasingly popular as food, chocolate-covered or not. From an evolutionary perspective, crickets offer more opportunities to learn about the last common insect ancestor; they hold more traits in common with other insects than fruit flies do. (Notably, insects make up more than 85 percent of animal species.) Dr. Extavour’s research aims at the fundamentals: How do embryos work? And what might that reveal about how the first animal came to be? Every animal embryo follows a similar journey: One cell becomes many, then they arrange themselves in a layer at the egg’s surface, providing an early blueprint for all adult body parts. But how do embryo cells — cells that have the same genome but aren’t all doing the same thing with that information — know where to go and what to do? © 2022 The New York Times Company

Keyword: Development of the Brain
Link ID: 28422 - Posted: 08.06.2022

Scientists know both a lot and very little about the brain. With billions of neurons and trillions of connections among them, and the experimental limitations of examining the seat of consciousness and bodily function, studying the human brain is a technical, theoretical and ethical challenge. And one of the biggest challenges is perhaps one of the most fundamental – seeing what it looks like in action. The U.S. Brain Research Through Advancing Innovative Neurotechnologies (BRAIN) Initiative is a collaboration among the National Institutes of Health, Defense Advanced Research Projects Agency, National Science Foundation, Food and Drug Administration and Intelligence Advanced Research Projects Activity and others. Since its inception in 2013, its goal has been to develop and use new technologies to examine how each neuron and neural circuit comes together to “record, process, utilize, store, and retrieve vast quantities of information, all at the speed of thought.” Just as genomic sequencing enabled the creation of a comprehensive map of the human genome, tools that elucidate the connection between brain structure and function could help researchers answer long-standing questions about how the brain works, both in sickness and in health. These five stories from our archives cover research that has been funded by or advances the goals of the BRAIN Initiative, detailing a slice of what’s next in neuroscience. Attempts to map the structure of the brain date back to antiquity, when philosophers and scholars had only the unaided eye to map anatomy to function. New visualization techniques in the 20th century led to the discovery that, just like all the other organs of the body, the brain is composed of individual cells – neurons. © 2010–2022, The Conversation US, Inc.

Keyword: Brain imaging; Development of the Brain
Link ID: 28421 - Posted: 08.06.2022

By Betsy Mason What is special about humans that sets us apart from other animals? Less than some of us would like to believe. As scientists peer more deeply into the lives of other animals, they’re finding that our fellow creatures are far more emotionally, socially, and cognitively complex than we typically give them credit for. A deluge of innovative research is revealing that behavior we would call intelligent if humans did it can be found in virtually every corner of the animal kingdom. Already this year scientists have shown that Goffin’s cockatoos can use multiple tools at once to solve a problem, Australian Magpies will cooperate to remove tracking devices harnessed to them by scientists, and a small brown songbird can sometimes keep time better than the average professional musician — and that’s just among birds. This pileup of fascinating findings may be at least partly responsible for an increase in people’s interest in the lives of other animals — a trend that’s reflected in an apparent uptick in books and television shows on the topic, as well as in legislation concerning other species. Public sentiment in part pushed the National Institutes of Health to stop supporting biomedical research on chimpanzees in 2015. In Canada, an outcry led to a ban in 2019 on keeping cetaceans like dolphins and orcas in captivity. And earlier this year, the United Kingdom passed an animal welfare bill that officially recognizes that many animals are sentient beings capable of suffering, including invertebrates like octopuses and lobsters. Many of these efforts are motivated by human empathy for animals we’ve come to see as intelligent, feeling beings like us, such as chimpanzees and dolphins. But how can we extend that concern to the millions of other species that share the planet with us?

Keyword: Vision; Hearing
Link ID: 28420 - Posted: 08.06.2022

By Virginia Morell In the summer of 2013, dolphin researcher Nicole Danaher-Garcia spotted something rare and remarkable in the animal world. As she stood on top of the bridge of a sport fishing yacht near Bimini in the Bahamas, she spied 10 adult Atlantic spotted dolphins she had never seen before—speeding into the waters of another group of dolphins. Most mammals attack intruders, but war wasn’t on the menu that day. Instead, the newcomers—eventually 46 in all—joined up with the resident dolphins, some 120 in number. Today, the two groups of Atlantic spotted dolphins (Stenella frontalis) have partially integrated, diving and swimming together, forming fast friendships, and likely even mating. It’s a “striking” display of tranquility between animals scientists usually consider rivals, says Richard Wrangham, a primatologist at Harvard University who was not involved with the study. Most mammals fight to protect mates and other resources if they encounter strangers entering their territory, he notes. This research, he says, may ultimately lead to a better understanding of the evolution of peacefulness. Danaher-Garcia, a behavioral ecologist, and her colleagues at the Dolphin Communication Project observed the two groups of dolphins in Bimini for 5 years, carrying out nearly 300 surveys. At first, the scientists only saw one small group of mixed Bimini and newcomer dolphins. But the next year, the scientists spotted a larger group of males and females of all ages from both communities mixing without “any signs of aggression,” she says. The dolphins continued their friendly behaviors through 2018, leading the team to suspect the two groups were merging. (Because of COVID-19 concerns, the scientists put their studies on hold in 2020.) The scientists discovered the newcomers had migrated from Little Bahama Bank, an area some 160 kilometers to the north known for its shallow seas, coral reefs, and sand banks. They were part of the White Sand Ridge (WSR) spotted dolphin community that another scientific team has been studying since the mid-1980s. © 2022 American Association for the Advancement of Science.

Keyword: Aggression; Sexual Behavior
Link ID: 28419 - Posted: 08.03.2022

By Andrew Jacobs At some point in the next few years, the 30 million smokers in the United States could wake up one day to find that cigarettes sold at gas stations, convenience stores and smoke shops contain such minuscule amounts of nicotine that they cannot get their usual fix when lighting up. Would the smokers be plunged into the agonizing throes of nicotine withdrawal and seek out their favorite, full-nicotine brand on illicit markets, or would they turn to vaping, nicotine gum and other less harmful ways to get that angst-soothing rush? Such scenarios inched closer to the realm of possibility in June, when the Food and Drug Administration said that it would move toward slashing nicotine levels in cigarettes in an effort to reduce the health effects of an addiction that claims 480,000 lives a year. The agency set next May as its timetable for introducing a fully developed proposal. But many experts hope regulators will champion an immediate 95 percent reduction in nicotine levels — the amount federally funded studies have determined is most effective for helping smokers kick the habit. It could be years before any new policy takes effect, if it survives opposition from the tobacco industry. Even so, health experts say any effort to decrease nicotine in cigarettes to nonaddictive levels would be a radical experiment, one that has never been implemented by any other country. The science of nicotine addiction has come a long way since 1964, when a U.S. Surgeon General report first linked smoking to cancer and heart disease, although it would take another two decades for the mechanics of nicotine dependence to be understood and widely accepted. Tobacco contains more than 7,000 chemicals, many of them harmful when burned and inhaled, but it is nicotine that keeps smokers coming back for more. Nicotine stimulates a surge of adrenaline in the brain while indirectly producing a flood of dopamine, the chemical that promotes feelings of contentment and relaxation. The effects, however, are short-lived, which is why heavy smokers need a fresh injection a dozen or more times a day. © 2022 The New York Times Company

Keyword: Drug Abuse
Link ID: 28418 - Posted: 08.03.2022

By Tim Vernimmen Just a few decades ago, even most biologists would have readily agreed that culture is a quintessentially human feature. Sure, they already knew there were dialects in birdsong, and good evidence that many birds largely learned these regional songs by copying other birds. They knew that some enterprising European songbirds called tits had learned how to open milk bottles by watching one another. Scientists had even reported that the practice of washing sweet potatoes in seawater had spread among the members of a Japanese colony of macaque monkeys. But these and similar behavioral differences between populations — ones that couldn’t easily be explained by differences in their genes or environment — seemed limited in scope. Compare that with human culture, which creates variation in nearly everything we do. In recent decades, however, scientists have learned that culture plays a much more pervasive role in the lives of nonhuman animals than anyone had imagined. “The whole field has absolutely exploded in discoveries in the present century,” says primatologist Andrew Whiten of the University of St. Andrews, Scotland, the author of a 2019 overview of cultural evolution in animals in the Annual Review of Ecology, Evolution, and Systematics. Whiten was one of the pioneers of the surge in animal culture research. In 1999, he oversaw an analysis in which primatologists published their findings from nearly four decades of studying wild chimpanzees, our closest living relatives. “We could show chimpanzees have multiple traditions affecting all different aspects of their lives,” he says — from foraging to tool use to courtship. Similar findings followed for several other apes and monkeys. © 2022 Annual Reviews

Keyword: Evolution; Learning & Memory
Link ID: 28417 - Posted: 08.03.2022

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

Keyword: Sleep
Link ID: 28416 - Posted: 08.03.2022

R. Douglas Fields Neuroscientists, being interested in how brains work, naturally focus on neurons, the cells that can convey elements of sense and thought to each other via electrical impulses. But equally worthy of study is a substance that’s between them — a viscous coating on the outside of these neurons. Roughly equivalent to the cartilage in our noses and joints, the stuff clings like a fishing net to some of our neurons, inspiring the name perineuronal nets (PNNs). They’re composed of long chains of sugar molecules attached to a protein scaffolding, and they hold neurons in place, preventing them from sprouting and making new connections. Given this ability, this little-known neural coating provides answers to some of the most puzzling questions about the brain: Why do young brains absorb new information so easily? Why are the fearful memories that accompany post-traumatic stress disorder (PTSD) so difficult to forget? Why is it so hard to stop drinking after becoming dependent on alcohol? And according to new research from the neuroscientist Arkady Khoutorsky and his colleagues at McGill University, we now know that PNNs also explain why pain can develop and persist so long after a nerve injury. Neural plasticity is the ability of neural networks to change in response to experiences in life or to repair themselves after brain injury. Such opportunities for effortless change are known as critical periods when they occur early in life. Consider how easily babies pick up language, but how difficult it is to learn a foreign language as an adult. In a way, this is what we’d want: After the intricate neural networks that allow us to understand our native language are formed, it’s important for them to be locked down, so the networks remain relatively undisturbed for the rest of our lives. All Rights Reserved © 2022

Keyword: Pain & Touch; Glia
Link ID: 28415 - Posted: 07.30.2022

By Sarah Wild In 2015, psychiatrist Mark Horowitz tried to come off his antidepressants. He reduced his dosage by a set proportion over the course of several months, which is much longer than what the United Kingdom’s guidelines recommended. But in the process of tapering, he experienced a storm of new symptoms, including anxiety, dizziness, and bouts of insomnia. “I’d wake in the morning, feeling like I was being chased by an animal on the edge of a cliff,” he says. Ultimately, he felt he had no choice but to go back on his medication. As it happened, Horowitz had recently completed a Ph.D. on the neurobiology of antidepressants. During his training, he recalls, his professors had told him that stopping antidepressants was fairly easy. Their view was supported by the scientific literature, which had found that any withdrawal symptoms were minor and faded quickly. Experiences such as Horowitz’s were considered an anomaly. But a series of widely reported studies published over the past seven years suggest that discontinuation symptoms are common and can be severe, including everything from panic attacks and flu-like symptoms to electric shock sensations in the head. The longer people remain on antidepressants and the higher their dose, the more likely they are to experience withdrawal symptoms. Each year, millions of people begin taking antidepressants. They have been shown to help anxiety sufferers feel calmer and lift the moods of those with severe depression and balance their emotions. For many, the intervention is lifesaving. Yet even today, few physicians inform their patients about the potential difficulties of coming off the medication. Most national guidelines suggest a slow taper, but there is little to no guidance on precisely how to do this. Patients who experience intense withdrawal symptoms may end up remaining on antidepressants or turning to online peer support groups for help.

Keyword: Depression
Link ID: 28414 - Posted: 07.30.2022

Ismaeel Yunusa Taking oxycodone at the same time as certain selective serotonin reuptake inhibitors (SSRIs), a commonly prescribed class of antidepressant, can increase the risk of opioid overdose, according to a study my colleagues and I published. Doctors prescribe the opioid oxycodone to treat moderate to severe pain after surgeries and injuries or certain conditions like cancer. Opioids are also a common drug of abuse. In the U.S., over 70% of drug overdose deaths in 2019 involved an opioid. Because many patients with depression also experience chronic pain, opioids are often coprescribed with antidepressants like SSRIs. Prior research has shown that certain SSRIs, namely fluoxetine (Prozac or Sarafem) and paroxetine (Paxil, Pexeva or Brisdelle), can strongly inhibit a liver enzyme crucial to the proper breakdown of drugs in the body, including oxycodone. The resulting increased concentration of oxycodone in the blood may lead to accidental overdose. To see whether different types of SSRIs might affect a patient’s risk of overdosing on oxycodone, my colleagues and I examined data from three large U.S. health insurance claims databases. We included over 2 million adults who began taking oxycodone while using SSRIs between 2000 and 2020. The average age of the group was around 50, and a little over 72% were women. A little over 30% were taking the SSRIs paroxetine and fluoxetine. We found that patients taking paroxetine or fluoxetine had a 23% higher risk of overdosing on oxycodone than those using other SSRIs. © 2010–2022, The Conversation US, Inc.

Keyword: Depression; Drug Abuse
Link ID: 28413 - Posted: 07.30.2022

By S. Hussain Hussain Ather You reach over a stove to pick up a pot. What you didn’t realize was that the burner was still on. Ouch! That painful accident probably taught you a lesson. It’s adaptive to learn from unexpected events so that we don’t repeat our mistakes. Our brain may be primed to pay extra attention when we are surprised. In a recent Nature study, researchers at the Massachusetts Institute of Technology found evidence that a hormone, noradrenaline, alters brain activity—and an animal’s subsequent behavior—in these startling moments. Noradrenaline is one of several chemicals that can flood the brain with powerful signals. Past research shows that noradrenaline is involved when we are feeling excited, anxious or alert and that it contributes to learning. But the new research shows it plays a strong role in responses to the unexpected. The M.I.T. team used a method called optogenetics to study noradrenaline in mice. The scientists added special light-sensitive proteins to neurons that work as an “off switch” for the cells when hit by pulses of laser light. They focused on modifying a brain area called the locus coeruleus, which holds cells responsible for releasing noradrenaline. With lasers, the researchers were able to stop these cells from producing the hormone in specific circumstances. They combined this method with photo tagging, a technique in which proteins flash with light, allowing the scientists to observe activity in the locus coeruleus cells and then determine how much noradrenaline was produced. Then the researchers designed a trial-and-error learning task for the rodents. The mice could push levers when they heard a sound. There were two sounds. After high-frequency tones of about 12 kilohertz, mice that pushed a lever were rewarded with water they could drink. For low-frequency tones, around four kilohertz, the mice that hit the lever got a slightly unpleasant surprise: a discomforting puff of air was blown at them. Over time, mice learned to push the lever only when they heard high-frequency tones because they got water when they did so. They avoided the lever when they heard low-frequency tones. © 2022 Scientific American

Keyword: Attention; Emotions
Link ID: 28412 - Posted: 07.30.2022

By Lesley Evans Ogden Hana aced her memory test. After viewing the contents of three identical boxes arrayed in an arc on the back deck of her home, the 3-year-old Cavalier King Charles spaniel had to remember which box held a treat — a task she quickly learned after just a few trials. Hana is part of a pack that has grown to nearly 40,000 pet dogs enrolled in a citizen science initiative known as the Dog Aging Project, founded in 2014. Understanding the biology of aging in companion dogs is one of two main goals of the project, says cofounder and codirector Matt Kaeberlein, a pathologist at the University of Washington in Seattle who focuses on aging. “The other is to do something about it.” Through veterinary records, DNA samples, health questionnaires and cognitive tests like Hana’s treat-finding challenge, the initiative of the University of Washington and Texas A&M University will track many aspects of dogs’ lives over time. Smaller subsets of the dogs, including Hana, will participate in more focused studies and more extensive evaluations. From all of this, scientists hope to spot patterns and find links between lifestyles and health from puppyhood through the golden years. The effort joins that of an earlier one: the Family Dog Project, spearheaded in the 1990s at Eötvös Loránd University (ELTE) in Budapest to study “the behavioral and cognitive aspects of the dog-human relationship,” with tens of thousands of canines participating through the decades. The two projects have begun collaborating across continents, and the scientists hope that such a large combined group of dogs can help them tease out genetic and environmental factors that affect how long dogs live, and how much of that time is spent in good health. © 2022 Annual Reviews

Keyword: Alzheimers; Development of the Brain
Link ID: 28411 - Posted: 07.30.2022

ByVirginia Morell We swat bees to avoid painful stings, but do they feel the pain we inflict? A new study suggests they do, a possible clue that they and other insects have sentience—the ability to be aware of their feelings. “It’s an impressive piece of work” with important implications, says Jonathan Birch, a philosopher and expert on animal sentience at the London School of Economics who was not involved with the paper. If the study holds up, he says, “the world contains far more sentient beings than we ever realized.” Previous research has shown honey bees and bumble bees are intelligent, innovative, creatures. They understand the concept of zero, can do simple math, and distinguish among human faces (and probably bee faces, too). They’re usually optimistic when successfully foraging, but can become depressed if momentarily trapped by a predatory spider. Even when a bee escapes a spider, “her demeanor changes; for days after, she’s scared of every flower,” says Lars Chittka, a cognitive scientist at Queen Mary University of London whose lab carried out that study as well as the new research. “They were experiencing an emotional state.” To find out whether these emotions include pain, Chittka and colleagues looked at one of the criteria commonly used for defining pain in animals: “motivational trade-offs.” People will endure the pain of a dentist’s drill for the longer term benefits of healthy teeth, for example. Similarly, hermit crabs will leave preferred shells to escape an electric shock only when given a particularly high jolt—an experiment that demonstrated crabs can tell the difference between weak and strong painful stimuli, and decide how much pain is worth enduring. That suggests crabs do feel pain and don’t simply respond reflexively to an unpleasant stimulus. Partly as a result of that study, crabs (and other crustaceans, including lobsters and crayfish) are recognized as sentient under U.K. law. © 2022 American Association for the Advancement of Science

Keyword: Pain & Touch; Evolution
Link ID: 28410 - Posted: 07.30.2022

ByCharles Piller In August 2021, Matthew Schrag, a neuroscientist and physician at Vanderbilt University, got a call that would plunge him into a maelstrom of possible scientific misconduct. A colleague wanted to connect him with an attorney investigating an experimental drug for Alzheimer’s disease called Simufilam. The drug’s developer, Cassava Sciences, claimed it improved cognition, partly by repairing a protein that can block sticky brain deposits of the protein amyloid beta (Aβ), a hallmark of Alzheimer’s. The attorney’s clients—two prominent neuroscientists who are also short sellers who profit if the company’s stock falls—believed some research related to Simufilam may have been “fraudulent,” according to a petition later filed on their behalf with the U.S. Food and Drug Administration (FDA). Schrag, 37, a softspoken, nonchalantly rumpled junior professor, had already gained some notoriety by publicly criticizing the controversial FDA approval of the anti-Aβ drug Aduhelm. His own research also contradicted some of Cassava’s claims. He feared volunteers in ongoing Simufilam trials faced risks of side effects with no chance of benefit. So he applied his technical and medical knowledge to interrogate published images about the drug and its underlying science—for which the attorney paid him $18,000. He identified apparently altered or duplicated images in dozens of journal articles. The attorney reported many of the discoveries in the FDA petition, and Schrag sent all of them to the National Institutes of Health (NIH), which had invested tens of millions of dollars in the work. (Cassava denies any misconduct [see sidebar, below].) But Schrag’s sleuthing drew him into a different episode of possible misconduct, leading to findings that threaten one of the most cited Alzheimer’s studies of this century and numerous related experiments. The first author of that influential study, published in Nature in 2006, was an ascending neuroscientist: Sylvain Lesné of the University of Minnesota (UMN), Twin Cities. His work underpins a key element of the dominant yet controversial amyloid hypothesis of Alzheimer’s, which holds that Aβ clumps, known as plaques, in brain tissue are a primary cause of the devastating illness, which afflicts tens of millions globally. In what looked like a smoking gun for the theory and a lead to possible therapies, Lesné and his colleagues discovered an Aβ subtype and seemed to prove it caused dementia in rats. If Schrag’s doubts are correct, Lesné’s findings were an elaborate mirage. © 2022 American Association for the Advancement of Science.

Keyword: Alzheimers
Link ID: 28409 - Posted: 07.23.2022

By Carolyn Gramling Hot or not? Peeking inside an animal’s ear — even a fossilized one — may tell you whether it was warm- or cold-blooded. Using a novel method that analyzes the size and shape of the inner ear canals, researchers suggest that mammal ancestors abruptly became warm-blooded about 233 million years ago, the team reports in Nature July 20. Warm-bloodedness, or endothermy, isn’t unique to mammals — birds, the only living dinosaurs, are warm-blooded, too. But endothermy is one of mammals’ key features, allowing the animals to regulate their internal body temperatures by controlling their metabolic rates. This feature allowed mammals to occupy environmental niches from pole to equator, and to weather the instability of ancient climates (SN: 6/7/22). When endothermy evolved, however, has been a mystery. Based on fossil analyses of growth rates and oxygen isotopes in bones, researchers have proposed dates for its emergence as far back as 300 million years ago. The inner ear structures of mammals and their ancestors hold the key to solving that mystery, says Ricardo Araújo, a vertebrate paleontologist at the University of Lisbon. In all vertebrates, the labyrinth of semicircular canals in the inner ear contains a fluid that responds to head movements, brushing against tiny hair cells in the ear and helping to maintain a sense of balance. That fluid can become thicker or thinner depending on body temperature. “Mammals have very unique inner ears,” Araújo says. Compared with cold-blooded vertebrates of similar size, the dimensions of mammals’ semicircular canals — such as thickness, length and radius of curvature — is particularly small, he says. “The ducts are very thin and tend to be very circular compared with other animals.” By contrast, fish have the largest for their body size. © Society for Science & the Public 2000–2022.

Keyword: Hearing; Evolution
Link ID: 28408 - Posted: 07.23.2022

By Stephanie Pappas As familiar to everyone as the COVID-causing coronavirus SARS-CoV-2 has become over the past two years, feverish research is still trying to parse a lingering puzzle. How, in fact, does the pandemic virus that has so changed the world cross over into the brain after entering the respiratory system? An answer is important because neurological complaints are some of the most common in the constellation of symptoms called long COVID. The mystery centers around the fact that brain cells don’t display the receptors, or docking sites, that the virus uses to get into nasal and lung cells. SARS-CoV-2, though, may have come up with an ingenious work-around. It may completely do away with the molecular maneuverings needed to attach to and unlock a cell membrane. Instead it wields a blunt instrument in the form of nanotube “bridges”—cylinders constructed of the common protein actin that are no more than a few tens of nanometers in diameter. These tunneling nanotubes extend across cell-to-cell gaps to penetrate a neighbor and give viral particles a direct route into COVID-impervious tissue. Researchers at the Pasteur Institute in Paris demonstrated the prospects for a nanotube-mediated cell crossing in a study in a lab dish that now needs to be confirmed in infected human patients. Given further proof, the findings could explain why some people who get COVID-19 experience brain fog and other neurological symptoms. Also, if the intercellular conduits could be severed, that might prevent some of these debilitating aftereffects of infection. The nanotube route “is a shortcut that propagates infection fast and between different organs, permissive or not permissive, to the infection,” says Chiara Zurzolo, a cell biologist at the Pasteur Institute, who conducted the study. “And it might be also a way for the virus to hide and escape the immune response.” © 2022 Scientific American

Keyword: Chemical Senses (Smell & Taste)
Link ID: 28407 - Posted: 07.23.2022

By Linda Searing People who drink a moderate amount of coffee — up to 3½ cups a day — might have a better chance at a longer life span, even if their coffee is lightly sweetened with sugar, according to research published in Annals of Internal Medicine. For about seven years, the researchers tracked the coffee consumption and health of 171,616 participants, who were an average of nearly 56 years old and were free of cancer and cardiovascular disease when the study started. They found that those who regularly drank 1½ to 3½ cups of coffee a day, whether plain or sweetened with about a teaspoon of sugar, were up to 30 percent less likely to die in that time frame from any cause, including cancer and cardiovascular disease, than were those who did not drink coffee. The type of coffee — whether instant, ground or decaffeinated — made no difference, but the results were described as inconclusive for the use of artificial sweeteners. The latest research does not prove that coffee alone was responsible for participants’ lowered mortality risk. Still, over the years, research has revealed a variety of health benefits for coffee, linking its consumption to a reduced risk for Type 2 diabetes, Parkinson’s disease, depression and more. Nutritionists often attribute the benefits of coffee to the abundance of antioxidants in coffee beans, which may help reduce internal inflammation and cell damage and protect against disease. Drinking caffeinated coffee also provides an energy boost and increased alertness. Caffeine, however, can disrupt sleep and be risky during pregnancy.

Keyword: Drug Abuse; Obesity
Link ID: 28406 - Posted: 07.23.2022

By Laura Sanders A dog’s brain is wired for smell. Now, a new map shows just how extensive that wiring is. Powerful nerve connections link the dog nose to wide swaths of the brain, researchers report July 11 in the Journal of Neuroscience. One of these canine connections, a hefty link between areas that handle smell and vision, hasn’t been seen before in any species, including humans. The results offer a first-of-its-kind anatomical description of how dogs “see” the world with their noses. The new brain map is “awesome, foundational work,” says Eileen Jenkins, a retired army veterinarian and expert on working dogs. “To say that they have all these same connections that we have in humans, and then some more, it’s going to revolutionize how we understand cognition in dogs.” In some ways, the results aren’t surprising, says Pip Johnson, a veterinary radiologist and neuroimaging expert at Cornell University College of Veterinary Medicine. Dogs are superb sniffers. Their noses hold between 200 million and 1 billion odor molecule sensors, compared with the 5 million receptors estimated to dwell in a human nose. And dogs’ olfactory bulbs can be up to 30 times larger than people’s. But Johnson wanted to know how smell information wafts to brain regions beyond the obvious sniffing equipment. To build the map, Johnson and colleagues performed MRI scans on 20 mixed-breed dogs and three beagles. The subjects all had long noses and medium heads, and were all probably decent sniffers. Researchers then identified tracts of white matter fibers that carry signals between brain regions. A method called diffusion tensor imaging, which relies on the movement of water molecules along tissue, revealed the underlying tracts, which Johnson likens to the brain’s “road network.” © Society for Science & the Public 2000–2022.

Keyword: Chemical Senses (Smell & Taste); Evolution
Link ID: 28405 - Posted: 07.22.2022