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By Hartmut Neven & Christof Koch The brain is a mere piece of furniture in the vastness of the cosmos, subject to the same physical laws as asteroids, electrons or photons. On the surface, its three pounds of neural tissue seem to have little to do with quantum mechanics, the textbook theory that underlies all physical systems, since quantum effects are most pronounced on microscopic scales. Newly proposed experiments, however, promise to bridge this gap between microscopic and macroscopic systems, like the brain, and offer answers to the mystery of consciousness. Quantum mechanics explains a range of phenomena that cannot be understood using the intuitions formed by everyday experience. Recall the Schrödinger’s cat thought experiment, in which a cat exists in a superposition of states, both dead and alive. In our daily lives there seems to be no such uncertainty—a cat is either dead or alive. But the equations of quantum mechanics tell us that at any moment the world is composed of many such coexisting states, a tension that has long troubled physicists. Taking the bull by its horns, the cosmologist Roger Penrose in 1989 made the radical suggestion that a conscious moment occurs whenever a superimposed quantum state collapses. The idea that two fundamental scientific mysteries—the origin of consciousness and the collapse of what is called the wave function in quantum mechanics—are related, triggered enormous excitement. Penrose’s theory can be grounded in the intricacies of quantum computation. Consider a quantum bit, a qubit, the unit of information in quantum information theory that exists in a superposition of a logical 0 with a logical 1. According to Penrose, when this system collapses into either 0 or 1, a flicker of conscious experience is created, described by a single classical bit. © 2024 SCIENTIFIC AMERICAN,
Keyword: Consciousness
Link ID: 29427 - Posted: 08.11.2024
Joe Hernandez If a human or another animal close to them dies, does a cat grieve the loss? That was the question a team of researchers from Oakland University in Michigan set out to answer when they surveyed hundreds of cat owners about their cat’s behavior after another cat or dog in the household passed away. The data showed that cats exhibited behaviors associated with grief — such as eating and playing less — more often after the death of a fellow pet, suggesting they may in fact have been in mourning. “It made me a little more optimistic that they are forming attachments with each other,” said Jennifer Vonk, a professor of psychology at Oakland University, who co-authored the study, published in the journal Applied Animal Behaviour Science. “It’s not that I want the cats to be sad,” Vonk went on, “[but] there is a part of us, I think, as humans that wants to think that if something happens to us our pets would miss us.” Though animals from elephants to horses to dogs have been shown to express signs of grief, less is known about the emotional life of the domesticated house cat. Vonk said she knew of only one other study on grief in domestic cats. For their research, Vonk and her coauthor, Brittany Greene, surveyed 412 cat caregivers about how their feline companion acted after another pet in the house died. They found that, after the death of a fellow pet, cats on average sought more attention from their owners, spent more time alone, appeared to look for the deceased animal, ate less and slept more. © 2024 npr
Keyword: Emotions; Evolution
Link ID: 29426 - Posted: 08.11.2024
By Michael S. Rosenwald Dr. J. Robin Warren, an Australian pathologist who shared a Nobel Prize for discovering that most stomach ulcers were caused by the bacterium Helicobacter pylori — and not, as had been widely believed, stress, alcohol or spicy foods — died on July 23 in Inglewood, Australia. He was 87. His death, at a care home, was announced by the University of Western Australia in Perth, where he was an emeritus professor for many years. His daughter-in-law Gigi Warren said the cause was complications after a recent fall. In 1984, Dr. Warren and his collaborator, the gastroenterologist Barry Marshall, published a paper in the British medical journal The Lancet describing their finding that the spiral-shaped bacterium now commonly called H. pylori festered in the stomachs of patients with ulcers and gastritis. Dr. Warren had first noticed the bacterium on a gastric biopsy sample in 1979. The paper’s conclusion upended centuries of conventional wisdom about the cause of ulcers. (Psychoanalysts had even written of the “peptic ulcer personality.”) Doctors typically prescribed stress reduction, a bland diet and, starting in 1977, drugs like Tagamet and Zantac to tame the burning acids. Severe cases were sometimes treated with surgery. When the study was published, gastroenterologists were skeptical. They expressed concern about whether to trust potentially paradigm-shifting findings made by two unknown researchers in Australia. And the idea that bacteria could even grow in the stomach was considered blasphemy. “For about 100 years, or 1,000 years, the standard teaching in medicine was that the stomach was sterile and nothing grew there because of corrosive gastric juices,” Dr. Warren told The New York Times in 2005 after he and Dr. Marshall won the Nobel Prize in Physiology or Medicine. “So everybody believed there were no bacteria in the stomach. When I said they were there, no one believed it.” © 2024 The New York Times Company
Keyword: Stress
Link ID: 29425 - Posted: 08.11.2024
Ross Ellenhorn and Dimitri Mugiani Earlier this month, an advisory panel rejected MDMA-assisted therapy for PTSD, possibly dooming US Food and Drug Administration (FDA) approval of the drug commonly called ecstasy. In a public meeting alongside FDA staff, panel members said that the research neither adequately accounted for abuse risks nor proved the drug’s efficacy in combination with psychotherapy. This decision dealt a major blow to Lykos Therapeutics, the for-profit public benefit corporation of the non-profit Multidisciplinary Association for Psychedelic Studies (Maps), which sponsored the trials. More broadly, the rejection has been described as a drastic setback for the psychedelic movement as a whole. For several years now, it seemed that greater acceptance and new legal spaces for psychedelics were a certainty. Then, scientists appeared at the FDA hearing and everything went dark. As practitioners and leaders in the realm of human transformation, and in creating and running organizations that serve individuals experiencing complex psychiatric symptoms, we believe in psychedelics as a force for good. Yet, to us, this FDA decision is the natural and expected outcome of a basic and fatal conceptual error that our brothers and sisters in the movement have adopted. By joining larger trends within the behavioral health milieu that focus on the elimination of distinct symptoms by drugs and by expert-driven techniques, today’s psychedelic movement is teetering on the edge of becoming unpsychedelic. What do we mean by this? Psychedelics free our minds to novelty, liberating us from habitual patterns. The common term for this property is “brain plasticity”, and it may be the core reason these substances can also affect areas of psychological suffering related to habits of the mind – those that experienced psychiatrists label as depression, anxiety, addiction and, yes, PTSD. Psychedelics are pro-imagination, pro-creativity, pro-innovation – qualities that research shows are at the very root of personal growth. © 2024 Guardian News & Media Limited
Keyword: Stress; Drug Abuse
Link ID: 29424 - Posted: 08.11.2024
By Maya L. Kapoor Six years ago, while shopping at a supermarket, Sadie Dingfelder spied her husband selecting a store-branded peanut butter jar. “Since when do you buy generic?” she asked, grabbing the jar from the cart. To her surprise, the frightened man turned out to be a total stranger. As usual, Dingfelder quickly began rewriting the unsettling interaction in her mind as a funny story, but a stark thought struck her this time: “Other people do not make this kind of mistake.” Dingfelder, a freelance science journalist, has prosopagnosia, or face blindness. It’s extremely difficult for her to recognize faces: She has gotten into cars with the wrong people; she has made plans with friends and then been surprised by who came. She once had to ask filmmaker John Waters, who met her at a museum for an interview, to help identify the museum staffer who had just introduced them — she couldn’t pick her out from a crowd of his fans. In “Do I Know You? A Faceblind Reporter’s Journey Into the Science of Sight, Memory, and Imagination,” Dingfelder begins coming to terms with her neurodivergence, weaving together science reporting — including brain scans, computerized tests, and assessments by medical researchers — and personal memoir in order to understand herself better. Ultimately, “Do I Know You?” is a question Dingfelder seems to be asking herself. By the end of the book, the answer feels like a firm yes. The term prosopagnosia, a portmanteau of the Greek words for “face” and “not knowing,” was coined by Joachim Bodamer, a psychiatrist and neurologist in Nazi Germany. Bodamer had encountered German soldiers with head traumas who had lost the ability to recognize people, including one soldier who blithely passed by his own mother at a train station.
Keyword: Attention
Link ID: 29423 - Posted: 08.11.2024
By Catherine Offord Lack of sleep wreaks havoc on the brain, making us worse learners and disrupting our memory, among other insults. Now, a study in mice suggests some of these effects could stem from changes in how brain cells are connected to one another. In a paper published today in Current Biology, researchers show that just hours of sleep deprivation reduce how many different types of synapses—the places where neurons meet—there are in brain regions associated with learning and memory. The findings hint at a novel way sleep might help keep us sharp, the team says. The study “is a technical tour de force,” says Marcos Frank, a neuroscientist at Washington State University who was not involved in the work. Still, he and others caution it’s not yet clear whether this result explains sleep deprivation’s unpleasant side effects. Nerve cells meet and communicate via chemicals across synapses, allowing signals to travel through the nervous system. There are trillions such connections in the human brain, forming and rearranging circuits of neurons that capture and store information. Various theories have tried to invoke these connections to explain the relationship between sleep and memory. One well-known idea from the early 2000s holds that the strength of synapses in the brain decreases when we sleep, and that this is important for conserving energy and prepping the brain for encoding new information the following day. But such theories often treat synapses as relatively uniform, says Seth Grant, a neuroscientist at the University of Edinburgh. In the past few years, his team and others have found that synapses are surprisingly diverse. They differ not only in the types of chemical, or neurotransmitter, they use to send signals, but in structure and in the composition of proteins present in the neurons surrounding them.
Keyword: Sleep
Link ID: 29422 - Posted: 08.03.2024
By Elena Kazamia It was a profound moment of connection. Carlos Casas could feel the elephant probing him, touching him with sound. The grunts emanating from the large male were of a frequency too low to hear, but Casas felt an agitation on his skin and deep inside his chest. “I was being scanned,” he says. At the time of the encounter, Casas was filming a project in Sri Lanka, and was holding a camera. But his interactions with the elephant gave the Catalonian filmmaker and installation artist an idea: What if instead of relying on images alone, he could use sound to create a physical connection between an audience of people and the subjects that fascinate him most, the animals with which we share life on this planet? Bestiari, his audio-visual project, now on display inside a former shipping warehouse at the Venice Biennale, weaves an immersive landscape for visitors. (You can explore some of the project, which was curated by Filipa Ramos, at the Instagram page for the installation.) Audio of the sounds the animals make is accompanied by video collected from remote camera traps set across national parks of Catalonia and Kenya, together with abstract film meant to capture the world as the animals see it, based on a combination of scientific research and artistic license. A series of texts serve as field guides to each animal featured in the installation. Entering the dark warehouse where Bestiari is housed, you are invited to lie on the floor, as if to fall asleep, before communing with seven different species: bees, donkeys, parakeets, snakes, bats, dolphins, and elephants. Each of the chosen species is represented by a speaker, customized to deliver the desired acoustics. Casas calls the speakers, “Trojan horses of meaning and communication.” The pitches and volumes were curated to be authentic to the original animal but perceptible by humans. For example, the echolocation chirps of bats have been slowed down to showcase the tonal progression of the sound. © 2024 NautilusNext Inc.,
Keyword: Hearing; Evolution
Link ID: 29421 - Posted: 08.03.2024
Andrew Gregory Health editor Almost half of dementia cases worldwide could be prevented or delayed, a study has found, as experts named 14 risk factors. The number of people living with dementia globally is forecast to nearly triple to 153 million by 2050, and researchers warn this presents a rapidly growing threat to health and social care systems. Global health and social costs linked to dementia exceed $1tn (£780bn) a year, the research shows. However, in a seismic report published by the Lancet, 27 of the world’s leading dementia experts concluded that far more cases could be avoided or delayed than previously thought. Addressing 14 modifiable risk factors, starting in childhood and continuing throughout life, could prevent or delay 45% of dementia cases, even as people live longer, the Lancet commission on dementia said. The findings were presented at the Alzheimer’s Association international conference in the US. In an interview with the Guardian, the lead author of the research, Prof Gill Livingston, said it was increasingly clear that there was much more that millions of people could and should do to reduce the risk of dementia. Speaking from the conference in Philadelphia, Livingston said: “Many people around the world believe dementia is inevitable but it’s not. Our report concludes that you can hugely increase the chances of not developing dementia or pushing back its onset. “It’s also important to stress that while we now have stronger evidence that longer exposure to risk has a greater effect … it’s never too early or too late to take action.” © 2024 Guardian News & Media Limited
Keyword: Alzheimers; Learning & Memory
Link ID: 29420 - Posted: 08.03.2024
By Laura Sanders Alzheimer’s disease is hard to diagnose. But proteins in the blood might provide clarity. A series of recent findings, presented at the annual Alzheimer’s Association International Conference in Philadelphia and in research papers, raise the possibility of a simple blood draw to help doctors figure out if a person’s cognitive problems are caused by Alzheimer’s — or something else. Decades ago, the only definitive way to get a diagnosis was an autopsy. Since then, scientists have figured out how to see the disease in living people. Spinal taps reveal levels of key proteins associated with the disease. And brain scans can illuminate the characteristic plaques and tangles that mar the brain in a person with Alzheimer’s disease. But spinal taps and brain scans are expensive and uncomfortable. A blood draw would lower barriers to diagnosis even further. That matters, because while Alzheimer’s has no cure, an easier, faster way to spot the disease could give people more time to discuss therapy options, including the newly available drugs that lower levels of amyloid, the sticky protein that accumulates in the brain in Alzheimer’s (SN: 7/17/23). Those drugs moderately slow the progression of the disease, but they come with serious side effects (SN: 6/7/21). “It’s an exciting moment,” says neuropathologist Eliezer Masliah of the National Institute on Aging in Bethesda, Md. “It’s an explosive moment,” one that has the potential to help reshape the diagnosis and treatment of the nearly 7 million people with Alzheimer’s in the United States, and millions more worldwide, he says. © Society for Science & the Public 2000–2024.
Keyword: Alzheimers
Link ID: 29419 - Posted: 08.03.2024
By Liam Drew In November 2008, neuroscientist Susana Carmona — then a postdoc studying attention deficit hyperactivity disorder — was driving two colleagues to a party when one of them revealed that she was thinking about having a child. The trio became so engulfed in conversation about how pregnancy might change her brain that they diverted from the party and headed to their laboratory to search the literature. They found numerous studies in rodents, but in humans, “there was basically nothing at all”, says Carmona. Shocked by this gap in research, Carmona and her colleagues convinced their mentor at the Autonomous University of Barcelona, Spain, Oscar Vilarroya, to let them run a study using magnetic resonance imaging (MRI) to measure the neuroanatomy of women before they became pregnant, and then again after they gave birth. Squeezed in alongside their main projects, the investigation took eight years and included dozens of participants. The results, published in 2016, were revelatory1. Two to three months after giving birth, multiple regions of the cerebral cortex were, on average, 2% smaller than before conception. And most of them remained smaller two years later. Although shrinkage might evoke the idea of a deficit, the team showed that the degree of cortical reduction predicted the strength of a mother’s attachment to her infant, and proposed that pregnancy prepares the brain for parenthood. Today, Carmona, now at the Gregorio Marañón Health Research Institute in Madrid, is one of several scientists uncovering how pregnancy and parenthood transform the brain. Elseline Hoekzema, one of Carmona’s passengers that evening in 2008, is another. In 2022, Hoekzema, who is now at the Amsterdam University Medical Centre in the Netherlands, confirmed that the cortical regions that shrink during pregnancy also function differently for at least a year after giving birth2. These studies and others, say researchers, highlight a transformational life event that has long been neglected by neuroscience — one that around 140 million women experience annually.
Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 29418 - Posted: 08.02.2024
By Yasemin Saplakoglu Two years ago, Sarah Shomstein realized she didn’t have a mind’s eye. The vision scientist was sitting in a seminar room, listening to a scientific talk, when the presenter asked the audience to imagine an apple. Shomstein closed her eyes and did so. Then, the presenter asked the crowd to open their eyes and rate how vividly they saw the apple in their mind. Saw the apple? Shomstein was confused. She didn’t actually see an apple. She could think about an apple: its taste, its shape, its color, the way light might hit it. But she didn’t see it. Behind her eyes, “it was completely black,” Shomstein recalled. And yet, “I imagined an apple.” Most of her colleagues reacted differently. They reported actually seeing an apple, some vividly and some faintly, floating like a hologram in front of them. In that moment, Shomstein, who’s spent years researching perception at George Washington University, realized she experienced the world differently than others. She is part of a subset of people — thought to be about 1% to 4% of the general population — who lack mental imagery, a phenomenon known as aphantasia. Though it was described more than 140 years ago, the term “aphantasia” was coined only in 2015. It immediately drew the attention of anyone interested in how the imagination works. That included neuroscientists. So far, they’re finding that aphantasia is not a disorder — it’s a different way of experiencing the world. Early studies have suggested that differences in the connections between brain regions involved in vision, memory and decision-making could explain variations in people’s ability to form mental images. Because many people with aphantasia dream in images and can recognize objects and faces, it seems likely that their minds store visual information — they just can’t access it voluntarily or can’t use it to generate the experience of imagery. That’s just one explanation for aphantasia. In reality, people’s subjective experiences vary dramatically, and it’s possible that different subsets of aphantasics have their own neural explanations. Aphantasia and hyperphantasia, the opposite phenomenon in which people report mental imagery as vivid as reality, are in fact two ends of a spectrum, sandwiching an infinite range of internal experiences between them. © 2024 the Simons Foundation.
Keyword: Attention; Vision
Link ID: 29417 - Posted: 08.02.2024
By Laura Hercher It is impossible, of course, to identify the precise moment we first suspected the changes in my mother were something other than normal aging. In my own imperfect memory, what rises up is the first morning of a weeklong trip to Rome, when my mother woke up at 2 A.M., got dressed and went down for breakfast. A hotel employee found her wandering from room to room, looking for toast and coffee. She was jet-lagged, my brother and I assured each other uneasily. It could happen to anyone. But weren’t there cues? Didn’t she notice the darkened lobby, the stillness, the clock? If we had known then, would it have helped? To date, no Food and Drug Administration–approved therapy exists for asymptomatic people at risk of Alzheimer’s disease (AD). My mother was not a smoker, drank in moderation, read books, took classes, and spent the week soaking up everything the tour guide had to tell her about Caravaggio and Bernini like she was prepping for the quiz. It was five years before my mother received a diagnosis of dementia. Today, a simple blood test can detect changes in the brain that predict AD up to 15 years before the first symptoms emerge. For researchers, tools for early detection give a peek at the full spectrum of AD, pinpointing early seeds of pathology deep inside the brain. Cognitive decline—what we typically think of as the disease itself—is merely an end-stage denouement. “Dementia is a result. Dementia is a symptom,” explains Clifford R. Jack, Jr., a neuroradiologist at the Mayo Clinic in Rochester, Minn., and chair of the Alzheimer’s Association (AA) working group responsible for new and controversial guidelines for the diagnosis of AD based on the underlying biology, not clinical presentation. Biomarkers for AD—signs of the physical changes in the brain that contribute to disease progression—have been available for more than two decades. In 2007 an international working group (IWG) of dementia experts described biomarkers as supporting evidence for a diagnosis of the disease, defined at that point largely as it was by neuropathologist Alois Alzheimer back in 1906: progressive memory loss, confusion and personality changes caused by distinctive plaques and tangles in the brain. For almost a century, those brain changes could only be confirmed on autopsy. While the affected person was alive, the label was merely presumptive. In fact, postmortem studies have found that up to 30 percent of people who received a clinical diagnosis of AD did not have the characteristic plaques and tangles.
Keyword: Alzheimers
Link ID: 29416 - Posted: 08.02.2024
Jake Rogers Nature Reviews Neuroscience (2024)Cite this article To better understand the therapeutic potential of the psychedelic drug psilocybin, we need a fuller understanding of its short-term and long-term effects on the human brain. In this study, Siegel et al. reveal individual-specific psilocybin-induced acute and persistent brain network changes in neurotypical young adults. The authors used longitudinal precision functional mapping — involving ~18 sessions of fMRI per individual — to capture individual-specific functional brain networks. Through this approach, acute (during) and persistent (between or after) intervention-induced changes to individual-specific network organization could be detected in young adult participants who received either high-dose psilocybin or dose-matched methylphenidate (a non-psychedelic stimulant chosen as an active control for psilocybin-induced cardiovascular and arousal effects) and who then, 1–2 weeks later, received the compound not administered first. Acutely, psilocybin caused not only widespread cortical functional connectivity (FC) changes (most prominently in association areas), but also disruption in subcortical regions connected with the default mode network (DMN), including the thalamus, basal ganglia, cerebellum and hippocampus. Furthermore, FC changes correlated with the intensity of the subjective experience documented using the 30-item mystical experience questionnaire (MEQ30). Several participants also received a second high dose of psilocybin and repeated an acute fMRI session six months later. Despite it being entirely plausible in a second acute session that individuals might experience the same effect, this repeated session revealed that individuals had substantially reduced or increased MEQ30 scores compared to their first acute session, and that the degree of the widespread brain changes and intensity of subjective experience correlated across and within individuals. By contrast, acute methylphenidate was associated with substantially less whole-brain FC disruption and most FC changes localized to sensorimotor systems. © 2024 Springer Nature Limited
Keyword: Drug Abuse; Depression
Link ID: 29415 - Posted: 08.02.2024
By Tina Hesman Saey A mind-bending parasite may one day deliver drugs to the brain. Toxoplasma gondii is a single-celled parasite that famously makes mice lose their fear of cats, but also can cause deadly foodborne illnesses (SN: 1/14/20). Now, researchers have engineered the parasite to deliver large therapeutic proteins to the brains of mice and into human brain cells grown in lab dishes, an international team of scientists reports July 29 in Nature Microbiology. Such proteins and the genes that produce them are often too big for viruses — the most common courier for gene therapy — to carry (SN: 10/20/23). If the parasite can be made safe for human use, the technique may eventually help treat a variety of neurological conditions. While critics doubt that the parasitic villain can ever be turned into a helpful hero, some researchers are intrigued by the idea. Microbes such as bacteria and parasites are usually viewed as bad guys, says Sara Molinari, a bacterial synthetic biologist at the University of Maryland in College Park who was not involved with the work. But microbes have evolved “pretty sophisticated relationships with our bodies,” she says. “The idea that we can leverage this relationship to instruct them to do good things for us is actually groundbreaking.” Current methods of delivering therapies to the brain often produce unpredictable results or have a hard time penetrating the protective shield known as the blood-brain barrier, says Shahar Bracha, a bioengineer and neuroscientist at MIT (SN: 5/2/23). © Society for Science & the Public 2000–2024.
Keyword: Brain imaging; Drug Abuse
Link ID: 29414 - Posted: 07.31.2024
Jon Hamilton A key protein that helps assemble the brain early in life also appears to protect the organ from Alzheimer’s and other diseases of aging. A trio of studies published in the past year all suggest that the protein Reelin helps maintain thinking and memory in ailing brains, though precisely how it does this remains uncertain. The studies also show that when Reelin levels fall, neurons become more vulnerable. There’s growing evidence that Reelin acts as a “protective factor” in the brain, says Li-Huei Tsai, a professor at MIT and director of the Picower Institute for Learning and Memory. “I think we’re on to something important for Alzheimer’s,” Tsai says. Various pieces of colorful trash, such as plastic bottle caps and plastics forks, are arranged in the shape of a human brain, on a light blue background. The research has inspired efforts to develop a drug that boosts Reelin or helps it function better, as a way to stave off cognitive decline. “You don't have to be a genius to be like, ‘More Reelin, that’s the solution,’” says Dr. Joseph Arboleda-Velasquez of Harvard Medical School and Massachusetts Eye and Ear. “And now we have the tools to do that.” From Colombia, a very special brain Reelin became something of a scientific celebrity in 2023, thanks to a study of a Colombian man who should have developed Alzheimer’s in middle age but didn’t. The man, who worked as a mechanic, was part of a large family that carries a very rare gene variant known as Paisa, a reference to the area around Medellin where it was discovered. Family members who inherit this variant are all but certain to develop Alzheimer’s in middle age. © 2024 npr
Keyword: Alzheimers; Development of the Brain
Link ID: 29413 - Posted: 07.31.2024
By Katie Moisse Monkeys can memorize a sequence of images and then toggle between them in their minds, a new study has found. Each mental move is associated with a tiny burst of brain activity that could be the neural representation of a thought, the study authors say. The study is the first to find evidence that an animal creates cognitive maps based on experience and later uses them exclusively, without any sensory input, to navigate a new task. It also marks one of the first times researchers have registered brain activity tied to an ongoing, complex thought process. “It’s a very fluid process—the process of thinking. And we have no way in animals to know what they’re thinking and therefore map what we record in the brain to what’s happening in the mind,” says study investigator Mehrdad Jazayeri, professor and director of education, brain and cognitive sciences at MIT’s McGovern Institute and a Howard Hughes Medical Institute investigator. In the new study, however, Jazayeri and his team designed a task that requires the animal to imagine a specific scenario at a specific time. “Imagination: There’s no magic to it; it’s a pattern of activity in the brain,” he says. Previous studies suggest rodents use cognitive maps to recreate the past and predict future possibilities. The new study, published last month in Nature, suggests monkeys also engage in such mental simulation and do so in the present—imagining states of the world that they just can’t see. “It’s a little bit like an animal navigating in the dark, where they’re using an internal map of where they are and where they’re going to update their sense of how close they are to their goal,” says Loren Frank, professor of physiology at the University of California, San Francisco, School of Medicine and a Howard Hughes Medical Institute investigator, who was not involved in the work. “Our brains do this all the time. But this study gives us a sense of how they do it and shows there’s an identifiable underlying process. It’s a really nice step forward.” Research image of the activity of a single neuron in a monkey brain. © 2024 Simons Foundation
Keyword: Learning & Memory; Evolution
Link ID: 29412 - Posted: 07.31.2024
By Hannah Richter Humans aren’t the only animals that lose hearing as they grow older. Almost every mammal studied struggles to pick up some sounds as they age. Some veterinarians even fit dogs for tiny hearing aids. But at least one species of bat appears to be an exception. Reporting this month on the preprint server bioRxiv, scientists have discovered that big brown bats (Eptesicus fuscus) don’t hear any worse as they grow older, possibly because their ability to echolocate is so critical to their survival. “Hearing is kind of their superpower,” says Mirjam Knörnschild, a behavioral ecologist at the Museum of Natural History Berlin who was not involved with the work. The research, she and others say, could lead to new ways to understand—and possibly treat—hearing loss in humans. Bats actually have two superpowers. Not only can most of them echolocate—bouncing sound off objects to hunt and navigate—they also tend to be remarkably long-lived for their size. Most small mammals are short-lived, but compared with mice of similar stature, the big brown bat lives up to five times as long, sometimes topping out at 19 years old. That makes the species a fascinating target for studies of aging, says Grace Capshaw, a postdoctoral researcher at Johns Hopkins University. The bat auditory system is fundamentally the same as that of every other mammal, she says, so “bats can be a really powerful model for comparing how hearing works.” To test whether big brown bats lose their hearing over time, Capshaw and colleagues divided 23 wild-caught bats into groups of young and old, making 6 years—the mean age of the species—the dividing line. The researchers determined the bats’ ages using a precise genetic method that involves comparing each animal’s DNA with the DNA of bats with known ages. They then sedated the animals to conduct a hearing examination similar to those done on human infants.
Keyword: Hearing
Link ID: 29411 - Posted: 07.31.2024
By Pam Belluck Scientists have made another major stride toward the long-sought goal of diagnosing Alzheimer’s disease with a simple blood test. On Sunday, a team of researchers reported that a blood test was significantly more accurate than doctors’ interpretation of cognitive tests and CT scans in signaling the condition. The study, published Sunday in the journal JAMA, found that about 90 percent of the time the blood test correctly identified whether patients with memory problems had Alzheimer’s. Dementia specialists using standard methods that did not include expensive PET scans or invasive spinal taps were accurate 73 percent of the time, while primary care doctors using those methods got it right only 61 percent of the time. “Not too long ago measuring pathology in the brain of a living human was considered just impossible,” said Dr. Jason Karlawish, a co-director of the Penn Memory Center at the University of Pennsylvania who was not involved in the research. “This study adds to the revolution that has occurred in our ability to measure what’s going on in the brain of living humans.” The results, presented Sunday at the Alzheimer’s Association International Conference in Philadelphia, are the latest milestone in the search for affordable and accessible ways to diagnose Alzheimer’s, a disease that afflicts nearly seven million Americans and over 32 million people worldwide. Medical experts say the findings bring the field closer to a day when people might receive routine blood tests for cognitive impairment as part of primary care checkups, similar to the way they receive cholesterol tests. “Now, we screen people with mammograms and PSA or prostate exams and other things to look for very early signs of cancer,” said Dr. Adam Boxer, a neurologist at the University of California, San Francisco, who was not involved in the study. “And I think we’re going to be doing the same thing for Alzheimer’s disease and hopefully other forms of neurodegeneration.” © 2024 The New York Times Company
Keyword: Alzheimers
Link ID: 29410 - Posted: 07.31.2024
By Miryam Naddaf Researchers have identified neurons in the brains of baby mice that enable them to form a unique, strong bond with their mother in the first few days of life. Stimulating these neurons in mouse pups that had been separated from their mother could mimic the soothing effect of their mother’s presence, and reduced behaviours associated with stress. The findings, published today in Science1, offer fresh clues about the formation of the mother–infant bond in mammals, and could help researchers to better understand how brain development influences behaviour. “We know very little about how the brains of infants make sense of their social world,” says study co-author Marcelo Dietrich, a neurobiologist at Yale University in New Haven, Connecticut. “When I started my lab ten years ago, and I wanted to study this kind of stuff, people said it was delusional. It will fail. It’s too difficult.” Now, “we show that it’s possible: one can do rigorous science and try to understand these mechanisms that are potentially very important for development and health”. “I see these neurons as the ‘I feel good with mommy’ neurons,” says Catharine Dulac, a neuroscientist at the University of Harvard in Cambridge, Massachusetts. “The features that [they] discovered provide some framework to think about humans.” Bonding in the brain Dietrich and his team studied nursing mouse pups that were between 16 and 18 days old. They used live imaging techniques to record activity in the zona incerta (ZI), a thin layer of grey matter located below the thalamus, while the animals interacted with their mother. © 2024 Springer Nature Limited
Keyword: Sexual Behavior
Link ID: 29409 - Posted: 07.27.2024
By Carl Zimmer After analyzing decades-old videos of captive chimpanzees, scientists have concluded that the animals could utter a human word: “mama.” It’s not exactly the expansive dialogue in this year’s “Kingdom of the Planet of the Apes.” But the finding, published on Thursday in the journal Scientific Reports, may offer some important clues as to how speech evolved. The researchers argue that our common ancestors with chimpanzees had brains already equipped with some of the building blocks needed for talking. Adriano Lameira, an evolutionary psychologist at the University of Warwick in Britain and one of the authors of the study, said that the ability to speak is perhaps the most important feature that sets us apart from other animals. Talking to each other allowed early humans to cooperate and amass knowledge over generations. “It is the only trait that explains why we’ve been able to change the face of the earth,” Dr. Lameira said. “We would be an unremarkable ape without it.” Scientists have long wondered why we can speak and other apes cannot. Beginning in the early 1900s, that curiosity led to a series of odd — and cruel — experiments. A few researchers tried raising apes in their own homes to see if living with humans could lead the young animals to speak. In 1947, for example, the psychologist Keith Hayes and his wife, Catherine, adopted an infant chimpanzee. They named her Viki, and, when she was five months old, they started teaching her words. After two years of training, the couple later claimed, Viki could say “papa,” “mama,” “up” and “cup.” By the 1980s, many scientists had dismissed the experiences of Viki and other adopted apes. For one, separating babies from their mothers was likely traumatic. “It’s not the sort of thing you could fund anymore, and with good reason,” said Axel Ekstrom, a speech scientist at the KTH Royal Institute of Technology in Stockholm. © 2024 The New York Times Company
Keyword: Language; Evolution
Link ID: 29408 - Posted: 07.27.2024