By Claudia López Lloreda Success tends to breed success. For instance, when a mouse dominates its opponents over and over, it becomes increasingly aggressive—helping to ensure victory in future fights. This “winner effect” takes hold thanks to multiple changes in synaptic plasticity, according to new findings published today in Cell. The results begin to reveal the mechanisms behind various forms of aggression seen in animals, says Jacob Nordman, assistant professor of molecular and integrative physiology at Southern Illinois University, who was not involved in the work. “There’s some aggression that is defensive; there’s some aggression that is pathological; there’s some aggression that’s territorial,” he says. “There might be a set of behaviors and, in turn, a set of circuits and possibly plasticity within those circuits, that speak to that.” Innate aggression is controlled by the ventromedial hypothalamus (VMH)—also known as the “attack” center—which shapes an animal’s social behaviors and fear response. But aggression can be learned, too. When paired with a mouse that is naturally docile, a more dominant mouse will eventually attack the other—and if it prevails, it tends to pick even longer fights with rivals over the coming days, thanks to synapse strengthening and increased activity in the VMH, a 2020 study reported. Full-blown and more generalized aggression emerges after even longer winning streaks, and it involves additional mechanisms, the new study suggests: Changes to neuronal excitability and dendritic spine morphology help cement the animal’s hawkishness. “Aggression is malleable—you can shape it,” says Scott Russo, professor of neuroscience at the Icahn School of Medicine at Mount Sinai, who was not involved with the study. “It’s not something that’s defined only by genetics, but that actually these circuits that support aggressive social behavior can change as a consequence of experience.” © 2024 Simons Foundation

Keyword: Aggression; Hormones & Behavior
Link ID: 29524 - Posted: 10.19.2024

By Yasemin Saplakoglu Around 2,500 years ago, Babylonian traders in Mesopotamia impressed two slanted wedges into clay tablets. The shapes represented a placeholder digit, squeezed between others, to distinguish numbers such as 50, 505 and 5,005. An elementary version of the concept of zero was born. Hundreds of years later, in seventh-century India, zero took on a new identity. No longer a placeholder, the digit acquired a value and found its place on the number line, before 1. Its invention went on to spark historic advances in science and technology. From zero sprang the laws of the universe, number theory and modern mathematics. “Zero is, by many mathematicians, definitely considered one of the greatest — or maybe the greatest — achievement of mankind,” said the neuroscientist Andreas Nieder (opens a new tab), who studies animal and human intelligence at the University of Tübingen in Germany. “It took an eternity until mathematicians finally invented zero as a number.” Perhaps that’s no surprise given that the concept can be difficult for the brain to grasp. It takes children longer to understand and use zero than other numbers, and it takes adults longer to read it than other small numbers. That’s because to understand zero, our mind must create something out of nothing. It must recognize absence as a mathematical object. “It’s like an extra level of abstraction away from the world around you,” said Benjy Barnett (opens a new tab), who is completing graduate work on consciousness at University College London. Nonzero numbers map onto countable objects in the environment: three chairs, each with four legs, at one table. With zero, he said, “we have to go one step further and say, ‘OK, there wasn’t anything there. Therefore, there must be zero of them.’” © 2024 Simons Foundation

Keyword: Attention
Link ID: 29523 - Posted: 10.19.2024

By Phil Plait I remember watching the full moon rise one early evening a while back. It was when I still lived in Colorado, and I was standing outside in my yard. I first noticed a glow to the east lighting up the flat horizon in the darkening sky, and within moments the moon was cresting above it, yellow and swollen—like, really swollen As it cleared the horizon, the moon looked huge! It also seemed so close that I could reach out and touch it; it was so “in my face” that I felt I could fall in. I gawped at it for a moment and then smiled. I knew what I was actually seeing: the moon illusion. Anyone who is capable of seeing the moon (or the sun) near the horizon has experienced this effect. The moon looks enormous there, far larger than it does when it’s overhead. I’m an astronomer, and I know the moon is no bigger on the horizon than at the zenith, yet I can’t not see it that way. It’s an overwhelming effect. But it’s not real. Simple measurements of the moon show it’s essentially the same size on the horizon as when it’s overhead. This really is an illusion. It’s been around awhile, too: the illusion is shown in cuneiform on a clay tablet from the ancient Assyrian city Nineveh that has been dated to the seventh century B.C.E. Attempts to explain it are as old as the illusion itself, and most come up short. Aristotle wrote about it, for example, attributing it to the effects of mist. This isn’t correct, obviously; the illusion manifests even in perfectly clear weather. A related idea, still common today, is that Earth’s air acts like a lens, refracting (bending) the light from the moon and magnifying it. But we know that’s not right because the moon is measurably the same size no matter where it is in the sky. Also, examining the physics of that explanation shows that it falls short as well. In fact, while the air near the horizon does indeed act like a lens, its actual effect is to make the sun and moon look squished, like flat ovals, not to simply magnify them. So that can’t be the cause either.

Keyword: Vision; Attention
Link ID: 29522 - Posted: 10.19.2024

By Christa Lesté-Lasserre Even if your cat hasn’t gotten your tongue, it’s most likely getting your words. Without any particular training, the animals—like human babies—appear to pick up basic human language skills just by listening to us talk. Indeed, cats learn to associate images with words even faster than babies do, according to a study published this month in Scientific Reports. That means that, despite all appearances to the contrary, our furtive feline friends may actually be listening to what we say. Cats have a long history with us—about 10,000 years at last count—notes Brittany Florkiewicz, an evolutionary psychologist at Lyon College who was not involved in the work. “So it makes sense that they can learn these types of associations.” Scientists have discovered a lot about how cats respond to human language in the past 5 years. In 2019, a team in Tokyo showed that cats “know” their names, responding to them by moving their heads and ears in a particular way. In 2022, some of the same researchers demonstrated that the animals can “match” photos of their human and feline family members to their respective names. “I was very surprised, because that meant cats were able to eavesdrop on human conversations and understand words without any special reward-based training,” says Saho Takagi, a comparative cognitive scientist at Azabu University and member of the 2022 study. She wondered: Are cats “hard-wired” to learn human language? To find out, Takagi and some of her former teammates gave 31 adult pet cats—including 23 that were up for adoption at cat cafés—a type of word test designed for human babies. The scientists propped each kitty in front of a laptop and showed the animals two 9-second animated cartoon images while broadcasting audio tracks of their caregivers saying a made-up word four times. The researchers played the nonsense word “keraru” while a growing and shrinking blue-and-white unicorn appeared on the screen, or “parumo” while a red-faced cartoon Sun grew and shrank. The cats watched and heard these sequences until they got bored—signaled by a 50% drop in eye contact with the screen.

Keyword: Language; Development of the Brain
Link ID: 29521 - Posted: 10.19.2024

By Joshua Cohen The contagious nature of bacterial or viral infections like strep throat or influenza is well understood. You’re at risk of catching the flu, for example, if someone near you has it, as the virus can be spread by way of droplets in the air, among other modes of transmission. But what about a person’s mental health? Can depression be contagious? A JAMA Psychiatry paper published earlier this year seemed to suggest so. Researchers reported finding “an association between having peers diagnosed with a mental disorder during adolescence and an increased risk of receiving a mental disorder diagnosis later in life.” They suggested that, among adolescents, mental health disorders could be “socially transmitted,” though their observational study could not establish any direct cause. It makes some intuitive sense. Psychologists have studied how moods and emotions can spread from person to person. Someone howling with laughter might be contagious in the sense that it makes you laugh, too. Similarly, seeing a friend in emotional pain can evoke feelings of despair — a phenomenon termed emotional contagion. For more than three decades, researchers have investigated whether mental health disorders, too, may be induced by our social environment. Studies have found mixed results on the extent to which friends’, peers’, and families’ mental health can impact an individual’s mental health in turn. The JAMA Psychiatry study — conducted by researchers at the University of Helsinki and other institutions — analyzed nationwide registry data on 713,809 Finnish citizens born between 1985 to 1997. The research team identified individuals from schools across Finland who had been diagnosed with a mental disorder by the time they were in ninth grade. They followed the rest of the cohort to record later diagnoses, up until the end of 2019.

Keyword: Depression
Link ID: 29520 - Posted: 10.16.2024

By Amber Dance For Cherise Irons, chocolate, red wine and aged cheeses are dangerous. So are certain sounds, perfumes and other strong scents, cold weather and thunderstorms. Stress and lack of sleep, too. She suspects all of these things can trigger her migraine attacks, which manifest in a variety of ways: pounding pain in the back of her head, exquisite sensitivity to the slightest sound, even blackouts and partial paralysis. Irons, 48, of Coral Springs, Florida, once worked as a school assistant principal. Now, she’s on disability due to her migraine. Irons has tried so many migraine medications she’s lost count — but none has helped for long. Even a few of the much-touted new drugs that have quelled episodes for many people with migraine have failed for Irons. Though not all are as impaired as Irons, migraine is a surprisingly common problem, affecting 14 percent to 15 percent of people. Yet scientists and physicians remain largely in the dark about how triggers like Irons’s lead to attacks. They have made progress nonetheless: The latest drugs, inhibitors of a body signaling molecule called CGRP, have been a blessing for many. For others, not so much. And it’s not clear why. The complexity of migraine probably has something to do with it. “It’s a very diverse condition,” says Debbie Hay, a pharmacologist at the University of Otago in Dunedin, New Zealand. “There’s still huge debate as to what the causes are, what the consequences are.”

Keyword: Pain & Touch
Link ID: 29519 - Posted: 10.16.2024

Nicola Davis Science correspondent The human sense of smell is nothing to turn one’s nose up at, research suggests, with scientists revealing we are far more sensitive to the order of odours captured by a sniff than previously thought. Charles Darwin is among those who have cast aspersions on our sense of smell, suggesting it to be “of extremely slight service” to humans, while scientists have long thought our olfactory abilities rather sluggish. “Intuitively, each sniff feels like taking a long-exposure shot of the chemical environment,” said Dr Wen Zhou, co-author of the research from the Chinese Academy of Sciences, adding that when a smell is detected it can seem like one scent, rather than a discernible mixture of odours that arrived at different times. “Sniffs are also separated in time, occurring seconds apart from one another,” she said. But now researchers have revealed our sense of smell operates much faster than previously thought, suggesting we are as sensitive to rapid changes in odours as we are to rapid changes in colour. A key challenge to probing our sense of smell, said Zhou, is that it has been difficult to create a setup that enables different smelly substances to be presented in a precise sequence in time within a single sniff. However, writing in the journal Nature Human Behaviour, Zhou and colleagues report how they did just that by creating an apparatus in which two bottles containing different scents were hooked up to a nosepiece using tubes of different lengths. These tubes were fitted with miniature check valves that were opened by the act of taking a sniff. © 2024 Guardian News & Media Limited

Keyword: Chemical Senses (Smell & Taste)
Link ID: 29518 - Posted: 10.16.2024

By Max Kozlov Forget the gauze and bandages: electrical stimulation near the ear might help to reduce bleeding. Researchers hope the technique could one day be used before surgery, childbirth and other events that pose a risk of dangerously uncontrolled bleeding. The treatment, called a ‘neural tourniquet’ by its creators, helps to turbocharge the activity of platelets, which are cell fragments that form blood clots, according to preliminary results presented at the 2024 Society for Neuroscience conference. “Anybody who’s worked in the emergency or operating room knows how gruesome it can be to lose somebody to bleeding,” Jared Huston, a trauma surgeon at the Feinstein Institutes for Medical Research in Manhasset, New York, who co-developed the treatment, tells Nature. “Bleeding can kill you much faster than sepsis.” Bleeding’s heavy toll Haemorrhage, or uncontrolled bleeding, accounts for about 60,000 deaths in the United States each year1. To try to reduce that number, Huston and his colleagues are developing a treatment that targets the vagus nerves, which are large networks of nerve fibres that link the body with the brain. Despite its name, the treatment does not work like a typical tourniquet that blocks blood flow to injured appendages. Instead, the electrical pulses help to stimulate the spleen, which stores about one-third of the body’s platelets. The stimulation prods the spleen to ready platelets to form a clot. To test the treatment, the researchers made small cuts in the ears of healthy pigs2. Compared with animals that didn’t receive the treatment, treated swine lost 50% less blood, and the duration of their bleeding was 40% shorter. © 2024 Springer Nature Limited

Keyword: Stress
Link ID: 29517 - Posted: 10.16.2024

By Elie Dolgin Cutting calorie intake can lead to a leaner body — and a longer life, an effect often chalked up to the weight loss and metabolic changes caused by consuming less food. Now, one of the biggest studies1 of dietary restrictions ever conducted in laboratory animals challenges the conventional wisdom about how dietary restriction boosts longevity. The study, involving nearly 1,000 mice fed low-calorie diets or subjected to regular bouts of fasting, found that such regimens do indeed cause weight loss and related metabolic changes. But other factors — including immune health, genetics and physiological indicators of resiliency — seem to better explain the link between cutting calories and increased lifespan. “The metabolic changes are important,” says Gary Churchill, a mouse geneticist at the Jackson Laboratory in Bar Harbor, Maine, who co-led the study. “But they don’t lead to lifespan extension.” To outside investigators, the results drive home the intricate and individualized nature of the body’s reaction to caloric restriction. “It’s revelatory about the complexity of this intervention,” says James Nelson, a biogerontologist at the University of Texas Health Science Center in San Antonio. The study was published today in Nature by Churchill and his co-authors, including scientists at Calico Life Sciences in South San Francisco, California, the anti-ageing focused biotech company that funded the study. Counting calories Scientists have long known that caloric restriction, a regimen of long-term limits on food intake, lengthens lifespan in laboratory animals2. Some studies3,4 have shown that intermittent fasting, which involves short bouts of food deprivation, can also increase longevity. © 2024 Springer Nature Limited

Keyword: Obesity
Link ID: 29516 - Posted: 10.12.2024

By Giorgia Guglielmi As the famed tale “Hansel and Gretel” makes clear, hunger can change behavior. The two lost and starving siblings give in to the temptation of a gingerbread cottage and ignore the danger lurking within—a wicked witch who has created the delicious house as a trap. Hunger is such a powerful driver that animals often pursue food at the expense of other survival needs, such as avoiding predators or recovering from injury. Hungry vicuñas, for example, will sometimes increase their risk of predation by pumas to get something to eat, behavioral ecologists have shown. Scientists know many of the key cells and circuits behind these competing drives—such as the hypothalamic “hunger neurons” that regulate food intake. But how the brain juggles the need to eat amidst other urges has remained mysterious, says Henning Fenselau, who leads the Synaptic Transmission in Energy Homeostasis group at the Max Planck Institute for Metabolism Research in Köln, Germany. “This is still a huge question [in neuroscience],” he says. In recent years, however, new clues about where and how hunger collides with rival motivations have come from technology to manipulate and monitor individual neurons across multiple brain regions at once. Those findings suggest that hunger neuron activity can override some brain signals, such as fear and pain. Exploring the brain’s ability to handle multiple needs simultaneously may offer insights into decision-making, anxiety and other neuropsychiatric conditions—helping to explain why people sometimes make maladaptive choices, says Nicholas Betley, associate professor of biology at the University of Pennsylvania. © 2024 Simons Foundation

Keyword: Obesity; Attention
Link ID: 29515 - Posted: 10.12.2024

By Angie Voyles Askham Unlike the primary sensory brain areas that process sights and sounds, the one that decodes scents also responds to other stimuli, such as images and words associated with an odor, according to a study published today in Nature. The extent to which neurons in the primary olfactory cortex, which includes the piriform cortex, respond to non-odor stimuli was surprising, says Marc Spehr, head of the Chemosensation Laboratory at RWTH Aachen University, who co-led the study. One neuron, for example, which activated in response to the scent of black licorice, also responded to the word “licorice,” images of the candy and the odor of anise seed, which is unrelated but has a similar scent. Cells in the amygdala also showed multimodal responses; one neuron, for example, responded to a banana scent as well as the word “banana.” “These aren’t odor signals that these cells are encoding; these cells are encoding concepts,” says Kevin Franks, associate professor of neurobiology at Duke University, who was not involved in the work but wrote a News and Views article on it. “So in this part of the brain, traditionally being considered this primary sensory area, you have sensory invariant conceptual representations of specific types of objects. And that’s really, really cool.” Smell-detecting neurons in the nose project into the brain’s olfactory bulb, which then passes information directly to the piriform cortex and other parts of the primary olfactory cortex. That means the piriform cortex lies only two synapses away from the stimuli it decodes, Franks says. In the visual system, on the other hand, a cell two synapses away from a photon is still in the retina, he says. Despite the limited odor processing that happens before the signal reaches the piriform cortex, there have been earlier hints that the area acts more like an association cortex than like other primary sensory areas, says Thorsten Kahnt, investigator at the U.S. National Institute on Drug Abuse, who was not involved in the work. © 2024 Simons Foundation

Keyword: Chemical Senses (Smell & Taste)
Link ID: 29514 - Posted: 10.12.2024

By Erica Goode Over the last decades, researchers who study animal behavior have succeeded in largely blurring the line between Homo sapiens and other animals. Like their human counterparts, animals feel emotions, they solve problems, they communicate and form complicated relationships, investigators have found. Any number of books — think of Ed Yong’s “An Immense World” or Marc Bekoff’s “The Emotional Lives of Animals” — have been dedicated to exploring these relatively recently recognized abilities. Yet few books on the ways animals communicate have been written through the eyes of a scientist as cautious and as thoughtful as zoologist Arik Kershenbaum, the author of “Why Animals Talk: The New Science of Animal Communication.” Kershenbaum, a lecturer and fellow at the University of Cambridge, is distrustful of simplistic explanations, wary of assumptions, devoted to caveats — few statements come without qualification. In Socratic fashion, he asks a lot of questions, the answers to which, in many cases, neither he nor anyone else can yet provide. That did not deter him from writing the book and it should not deter other people from reading it. But those who pick up “Why Animals Talk” expecting to find proof of animal telepathy or hoping for a dictionary of elephant-speak or a word-for-word translation of humpback whale songs, will be disappointed. (On Amazon, one disgruntled reviewer summarized the book: “Animals don’t really talk – The End.”) If there is a message that Kershenbaum wants to get across, it’s that, as much as we’d like to be able to hold conversations with our pets or chat with chimpanzees at the zoo, it makes no sense to expect animals to communicate in the same way that humans do, “with the same equipment as we have, the same ears and eyes and brains.”

Keyword: Animal Communication; Language
Link ID: 29513 - Posted: 10.12.2024

By Laura Sanders CHICAGO — Big news for fighting sisters: Scientists have found the sensors that signal the painful zing of a hair pull. And this pain message can rip along a nerve fiber at about 100 miles an hour, placing it among the fastest known pain signals. The discovery, presented October 8 at the annual meeting of the Society for Neuroscience, offers insight into the diverse ways our bodies sense and respond to different sorts of pain. Pain can come from many catastrophes — cuts, jabs, pinches, cramps, bites, slaps, stubbing a toe in the dark. And while our bodies can generally tell these insults apart thanks to a variety of biological pathways, they all hurt. “It’s not surprising that we have figured out many, many ways to make [pain] happen,” says neuroscientist Gregory Dussor of the University of Texas at Dallas. “Because when it doesn’t, we don’t live.” Laboratory tests showed a hair pull to be about 10 times as painful as a pinprick, neuroscientist Emma Kindström of Linköping University in Sweden and colleagues found. The pain of the pull relies on a large, propeller-shaped protein called PIEZO2, further tests showed. That sensor was known to detect mechanical forces, including light touches, but wasn’t thought to detect acute pain signals. People who lack this protein don’t feel hair-pull pain. A hair-pull signal moves along nerve fibers much faster than other sorts of pain, Kindström says, traveling in bursts along an insulated conduit called an Aβ nerve fiber. Other kinds of pain signals, such as a burn from a hot stove, travel more slowly along different kinds of fibers. © Society for Science & the Public 2000–2024.

Keyword: Pain & Touch
Link ID: 29512 - Posted: 10.12.2024

By Megan TwoheyDanielle Ivory and Carson Kessler As marijuana legalization spreads across the country, people are consuming more of the drug, more often and at ever-higher potencies. Most of the tens of millions of people using marijuana, for health benefits or for fun, don’t experience problems. But a growing number, mainly heavy users, have experienced addiction, psychosis and other harmful effects, The New York Times found. “Cannabis is a lot of things at once,” said Dr. Kevin Gray, a psychiatrist and specialist in bio-behavioral medicine at Medical University of South Carolina Health. “It can be medically therapeutic. It also can be highly problematic.” In interviews and surveys, hundreds of people told The Times about serious — sometimes frightening — symptoms that they were stunned to learn could be caused by cannabis. Here are some of their stories. David Krumholtz, an actor known for films like “10 Things I Hate About You” and TV shows like “Numb3rs,” resumed smoking marijuana in 2016, after a decade-long break. Within months, he started to experience cycles of intense nausea and vomiting — a sometimes debilitating condition called cannabinoid hyperemesis syndrome. It can lead to dehydration, seizures, kidney failure, cardiac arrest and even death in rare instances. He lost 100 pounds and was in and out of emergency departments. At home in New Jersey, he would spend 10 hours at a time in hot baths, which for unknown reasons can temporarily relieve symptoms. “I had numbness in my extremities, pain in my chest and my blood pressure skyrocketed,” he said. Mr. Krumholtz, 46, believes he would have eventually died had he not suffered an episode that almost derailed his dream job, a role in the blockbuster 2023 film “Oppenheimer,” and inspired him to quit marijuana for good. © 2024 The New York Times Company

Keyword: Drug Abuse
Link ID: 29511 - Posted: 10.09.2024

By Laurie McGinley When Dennis Carr learned he had early Alzheimer’s disease, he immediately thought of his older brother who had died of the illness in 2023. “There was not much anyone could do,” Carr said of his brother’s long decline. “You could see him diminishing.” Today, Carr is trying a new treatment called Leqembi that has been shown to modestly slow the disease for people in the initial stages of Alzheimer’s. Carr knows it is not a cure but he wants to buy time — to be with his family, to work and to give scientists a chance to find more solutions. “I’m hoping this is the first steppingstone to something better,” said Carr, 74, an electrical contractor in Montgomery County, Pa. Carr’s experience offers a glimpse of the shifting landscape of Alzheimer’s, a memory-robbing disease that affects more than 6 million Americans and is the seventh leading cause of death in the United States. Two new treatments, including Carr’s, target toxic clumps of a protein called amyloid beta in the brain and are the first to slow progression of the illness. Blood tests could revolutionize the way the illness is diagnosed. Lifestyle factors such as diet and exercise are showing promise in helping reduce the risk of cognitive decline. “Progress against Alzheimer’s has been unprecedented,” said Howard Fillit, co-founder and chief science officer of the Alzheimer’s Drug Discovery Foundation, a nonprofit that funds the development of drugs and diagnostics. “But we have a long way to go.” The new FDA-approved Alzheimer’s treatment Leqembi is prepared at Abington Neurological Associates in Abington, Pa., on Nov. 7. (Hannah Yoon for The Washington Post) Doctors used to refer to Alzheimer’s as “diagnose and adios” because they had little to offer patients, said Adam Boxer, a neurologist at the University of California at San Francisco. “But now we see light at the end of the tunnel,” he said. “We might be able to have a big impact.”

Keyword: Alzheimers
Link ID: 29510 - Posted: 10.09.2024

By Brendan Borrell, Ellie Kincaid A psychiatry researcher who received a warning letter from the U.S. Food and Drug Administration earlier this year committed research misconduct, another federal watchdog found. Bret Rutherford, formerly a research psychiatrist at the New York State Psychiatric Institute and Columbia University, “engaged in research misconduct by recklessly falsely reporting that all human research subjects met the inclusion/exclusion criteria for late-life depression studies,” according to a case summary from the U.S. Office of Research Integrity (ORI) published today. As The Transmitter previously reported, a suicide that occurred during one of Rutherford’s trials in 2021 was followed by a suspension of his research a few months later. The U.S. Office of Human Research Protections subsequently halted all federally funded research involving human participants at the institute in June 2023 and launched a review of its research practices. The ORI’s findings detail how in five published papers, Rutherford reported that 45 research participants were eligible for clinical studies, when in fact they were taking antidepressants or other medications that should have excluded them from participation. Rutherford also included 15 participants who took medications during a 28-day washout period before the trial when they were not supposed to be taking the medications, and he reported full washout periods for 8 participants who underwent shorter periods. The false reporting affected “the reported clinical research methods and results” of the five articles, the ORI’s finding stated. Three of the articles have been retracted, and the other two have been corrected. The Transmitter previously reported on the corrections and two of the retractions, which reference protocol violations in a clinical trial of whether levodopa, a drug for Parkinson’s disease, could help older adults with depression. © 2024 Simons Foundation

Keyword: Depression
Link ID: 29509 - Posted: 10.09.2024

By Sara Reardon Researchers have mapped nearly 140,000 neurons in the fruit-fly brain. This version shows the 50 largest. Credit: Tyler Sloan and Amy Sterling for FlyWire, Princeton University (ref. 1) A fruit fly might not be the smartest organism, but scientists can still learn a lot from its brain. Researchers are hoping to do that now that they have a new map — the most complete for any organism so far — of the brain of a single fruit fly (Drosophila melanogaster). The wiring diagram, or ‘connectome’, includes nearly 140,000 neurons and captures more than 54.5 million synapses, which are the connections between nerve cells. “This is a huge deal,” says Clay Reid, a neurobiologist at the Allen Institute for Brain Science in Seattle, Washington, who was not involved in the project but has worked with one of the team members who was. “It’s something that the world has been anxiously waiting for, for a long time.” The map1 is described in a package of nine papers about the data published in Nature today. Its creators are part of a consortium known as FlyWire, co-led by neuroscientists Mala Murthy and Sebastian Seung at Princeton University in New Jersey. Seung and Murthy say that they’ve been developing the FlyWire map for more than four years, using electron microscopy images of slices of the fly’s brain. The researchers and their colleagues stitched the data together to form a full map of the brain with the help of artificial-intelligence (AI) tools. But these tools aren’t perfect, and the wiring diagram needed to be checked for errors. The scientists spent a great deal of time manually proofreading the data — so much time that they invited volunteers to help. In all, the consortium members and the volunteers made more than three million manual edits, according to co-author Gregory Jefferis, a neuroscientist at the University of Cambridge, UK. (He notes that much of this work took place in 2020, when fly researchers were at loose ends and working from home during the COVID-19 pandemic.) © 2024 Springer Nature Limited

Keyword: Brain imaging; Development of the Brain
Link ID: 29508 - Posted: 10.05.2024

By Simon Makin The word “bionic” conjures sci-fi visions of humans enhanced to superhuman levels. It’s true that engineering advances such as better motors and batteries, together with modern computing, mean that the required mechanical and electronic systems are no longer a barrier to advanced prostheses. But the field has struggled to integrate these powerful machines with the human body. That’s starting to change. A recent trial tested one new integration technique, which involves surgically reconstructing muscle pairs that give recipients a sense of the position and movement of a bionic limb. Signals from those muscles control robotic joints, so the prosthesis is fully under control of the user’s brain. The system enabled people with below-knee amputations to walk more naturally and better navigate slopes, stairs and obstacles, researchers reported in the July Nature Medicine. Engineers have typically viewed biology as a fixed limitation to be engineered around, says bioengineer Tyler Clites, who helped develop the technique several years ago while at MIT. “But if we look at the body as part of the system to be engineered, in parallel with the machine, the two will be able to interact better.” That view is driving a wave of techniques that reengineer the body to better integrate with the machine. Clites, now at UCLA, calls such techniques “anatomics,” to distinguish them from traditional bionics. “The issue we were tackling wasn’t an engineering problem,” he says. “The way the body had been manipulated during the amputation wasn’t leaving it in a position to be able to control the limbs we were creating.” In an anatomics approach, bones are exploited to provide stable anchors; nerves are rerouted to create control signals for robotic limbs or transmit sensory feedback; muscles are co-opted as biological amplifiers or grafted into place to provide more signal sources. © Society for Science & the Public 2000–2024.

Keyword: Robotics
Link ID: 29507 - Posted: 10.05.2024

By Christina Caron It’s not uncommon for our minds to unleash a torrent of difficult feelings under the cover of darkness: sadness and negative thoughts may surface at night, making sleep hard to come by. On social media and elsewhere people often refer to this as “nighttime depression.” But is that really a thing? And if so, why do some people get blue at night? Feeling down after dusk doesn’t necessarily mean that you have a mental health condition, experts said. Understanding why it happens can help you take steps to feel better. What is nighttime depression? Nighttime depression is a colloquial term for depressive symptoms that either appear or worsen late at night. It is not itself a diagnosis. While anxiety can also ramp up at night, and tends to make people feel agitated, tense and restless, nighttime depression is best characterized as a low mood. “It’s a sense of sadness,” said Dr. Theresa Miskimen Rivera, a clinical professor of psychiatry at Rutgers University and president-elect of the American Psychiatric Association. “It’s that feeling of: There’s no joy. My life is so blah.” Nighttime depression can also feel uncomfortable — “not only in your mind, but in your body,” Dr. Rivera added, especially if these feelings interfere with getting enough sleep. © 2024 The New York Times Company

Keyword: Depression; Sleep
Link ID: 29506 - Posted: 10.05.2024

By Sofia Quaglia Parenting can be lots of work for a bird: all that flying back and forth transporting grubs and insects to a nest of demanding young. But some birds manage to forgo caring for their chicks — while still ensuring they’re well looked after. These birds lay their eggs in the nests of other birds that unknowingly adopt the hatchlings, nourishing and protecting them as their own. Only about 1 percent of all bird species resort to this sneaky family planning method, called obligate brood parasitism, but it has evolved at least seven separate times in the history of birds and is a way of life for at least 100 species. Since some brood parasites rely on several different bird species as foster parents, more than a sixth of all species in the avian world care for chicks that aren’t their own at some point. Throughout the millennia, these trespassers have evolved ingenious ways to fool the hosts, and the hosts have developed equally clever ways to protect themselves and their own. At each stage of the nesting cycle, it’s a game of subterfuge that plays out in color, sound and behavior. “There’s always something new — it’s like, ‘Oh, man, this group of birds went down a slightly different pathway,’” says behavioral ecologist Bruce Lyon of the University of California, Santa Cruz, who studies the black-headed duck (Heteronetta atricapilla), the sole obligate parasitic duck species. While many mysteries remain, new research is constantly unearthing just how intense this evolutionary tug-of-war can get.

Keyword: Sexual Behavior; Evolution
Link ID: 29505 - Posted: 10.05.2024