By Sara Reardon Last week’s decision by the US Food and Drug Administration (FDA) to reject MDMA, also known as ecstasy, as a psychiatric treatment surprised many researchers. Lykos Therapeutics, the company that has been testing MDMA, plans to ask the FDA to reconsider the decision, but scientists are now wondering what the agency’s ruling will mean for other potential psychedelic therapies. In a press release posted on 9 August, Lykos, which is based in San Jose, California, said that the FDA had sent a letter requesting that the company undertake another large-scale trial of the drug in people with post-traumatic stress disorder (PTSD) and resubmit its application. “The FDA request for another study is deeply disappointing,” Lykos chief executive Amy Emerson said in the press release, adding that the company plans to work with the agency to “resolve scientific disagreements”. Conducting another study “would take several years”, she said, adding that Lykos has already addressed many of the FDA’s concerns. In an e-mail to Nature, Lykos declined to provide the complete letter detailing the agency’s specific concerns and directed the news team instead to its press release. Experts say that without access to the letter, it’s hard to determine why the FDA reached the decision it did. “We really are going off incomplete information,” says Mason Marks, who studies drug policy at Florida State University in Tallahassee, adding that he was “a little surprised” by the agency’s decision. Trial concerns But Marks points out that the FDA typically follows the advice of its independent advisory committees — and the one that evaluated MDMA in June overwhelmingly voted against approving the drug, citing problems with clinical trial design that the advisers felt made it difficult to determine the drug’s safety and efficacy. One concern was about the difficulty of conducting a true placebo-controlled study with a hallucinogen: around 90% of the participants in Lykos’s trials guessed correctly whether they had received the drug or a placebo, and the expectation that MDMA should have an effect might have coloured their perception of whether it treated their symptoms. © 2024 Springer Nature Limited

Keyword: Drug Abuse; Depression
Link ID: 29433 - Posted: 08.15.2024

By Sara Reardon Stress can make people feel sick, and bacteria in the gut might be to blame, according to a study1 in mice. The research suggests that a stressed brain directly shuts down specific glands in the gut, affecting gut bacteria and the body’s broader immune system. The study “is a technical tour de force”, says neuroscientist John Cryan at University College Cork in Ireland, who reviewed the study. Most work on the gut–brain connection has focused on how bacteria affect the brain, so Cryan welcomes research into how psychological states can exert ‘top-down’ control of bacteria. “It’s a really cool part of the puzzle”, he says. The research was published on 8 August in Cell. Researchers have long known that the gut and brain ‘talk’ to each other. Under stress, the brain spurs the release of hormones that can trigger gut conditions such as inflammatory bowel disease. And certain bacteria in the gut can release chemical signals that affect the brain and behaviour. Your brain could be controlling how sick you get — and how you recover But the neural communication pathways are less well understood. To find out more, neuroscientist Ivan de Araujo at the Max Planck Institute for Biological Cybernetics in Tübingen, Germany, and his colleagues focused on small organs called Brunner’s glands that are found in the walls of the small intestine. Little is known about these glands, other than that they produce mucus and contain numerous neurons. De Araujo’s team found that removing the Brunner’s glands of mice made the animals more susceptible to infection. It also raised markers of inflammation, a flood of immune chemicals and cells that can damage tissues. The team saw a similar effect in humans: people who’d had tumours removed from the part of the gut containing Brunner’s glands had higher levels of white blood cells — a marker of inflammation — than people who’d had tumours removed from other areas. © 2024 Springer Nature Limited

Keyword: Stress; Neuroimmunology
Link ID: 29432 - Posted: 08.13.2024

By Andrew Jacobs The journal Psychopharmacology has retracted three papers about MDMA-assisted therapy based on what the publication said was unethical conduct at one of the study sites where the research took place. Several of the papers’ authors are affiliated with Lykos Therapeutics, the drug company whose application for MDMA-assisted therapy to treat post-traumatic stress disorder was rejected last week by the Food and Drug Administration. The company said the research in the retracted papers was not part of its application to the F.D.A. In declining to approve Lykos’s application, the agency cited concerns about missing data and problems with the way the company’s study was designed, according to a statement released by Lykos on Friday. The F.D.A. has asked Lykos to conduct an additional clinical trial of its MDMA-assisted therapy, which would have been the first psychedelic medicine to win approval by federal regulators. Lykos has said it would appeal the decision. The journal retraction was first reported by Stat, the health and medical news website. On Sunday, Lykos said that it disagreed with Psychopharmacology’s decision and that it would file an official complaint with the Committee on Publication Ethics, a nonprofit that sets guidelines for academic publications. “The articles remain scientifically sound and present important contributions to the study of potential treatments for PTSD,” the company said in the statement. The incident cited by Psychopharmacology has been well documented. © 2024 The New York Times Company

Keyword: Stress; Drug Abuse
Link ID: 29431 - Posted: 08.13.2024

By Sneha Khedkar About 10 years ago, when Michael Yartsev set up the NeuroBat Lab, he built a new windowless cave of sorts: a fully automated bat flight room. Equipped with cameras and other recording devices, the remote-controlled space has enabled his team to study the neuronal basis of navigation, acoustic and social behavior in Egyptian fruit bats without having any direct interaction with the animals. “In our lab, there’s never a human involved in the experiments,” says Yartsev, associate professor of bioengineering at the University of California, Berkeley. The impetus to create the space was clear. The setup, paired with wireless electrodes inserted in the bats’ hippocampus, has helped the team demonstrate, for example, that place cells encode a flying bat’s current, past and future locations. Also, a mountain of evidence suggests that the identity, sex and stress levels of human experimenters can influence the behavior of and brain circuit activity in other lab animals, such as mice and rats. Now Yartsev and his team have proved that “experimenter effects” hold true for bats, too, according to a new study published last month in Nature Neuroscience. The presence of human experimenters changed hippocampal neuronal activity in bats both at rest and during flight—and exerted an even stronger influence than another fruit bat, the study shows. The team expected that humans would influence neural activity, Yartsev says, “but we did not expect it to be so profound.” © 2024 Simons Foundation

Keyword: Attention; Hearing
Link ID: 29430 - Posted: 08.13.2024

Ari Daniel On a dark night in northern Belize in early May, Gliselle Marin stands in the middle of a patchy forest in the Lamanai Archaeological Reserve, about a two-hour drive from where she grew up. Every few minutes, she and her fellow researchers sweep their headlamps over the nets they’ve strung up to see if they’ve caught anything. Before long, a chirping leaf-nosed bat the color of hot cocoa is entangled. He’s small — about the size of a lemon. Marin works carefully and quickly to free him. “We’re trying to get the net off of him,” she says. “It’s kind of like a puzzle. I like to take the feet out first. And then I do one wing, then the head.” Within a minute, the tiny bat is out. Marin jots down some basic information about the bat and then places him inside a cloth bag for further study that night. All the tools Marin needs for this kind of delicate extraction — including an ordinary crochet hook, for the worst tangles — fit into a fanny pack that’s adorned with little printed bats. The scientist also sports bat earrings, as well as a tattoo of small bats flying up the nape of her neck. Marin is a biology PhD student at York University in Toronto, and she’s here with the “Bat-a-thon,” a group of 80-some bat researchers who converge on this part of Belize each year to study these winged mammals. Growing up, Marin’s family had bats roosting under their house. “But when I actually started working with them and realizing we have close to 80 species of bats,” she says, “I was like, ‘Okay, it’s kind of crazy that I’ve been in science my whole life and was never taught that we have this diversity of bats in Belize.’” Over time, she’s come to admire not just the cornucopia of species, but the spectacular array of abilities and behaviors of these adaptable little animals. Scientists, she says, have only scratched the surface when it comes to understanding these furry, flying mammals. © 2024 npr

Keyword: Hearing
Link ID: 29429 - Posted: 08.13.2024

By Roni Caryn Rabin Even light drinking was associated with an increase in cancer deaths among older adults in Britain, researchers reported on Monday in a large study. But the risk was accentuated primarily in those who had existing health problems or who lived in low-income areas. The study, which tracked 135,103 adults aged 60 and older for 12 years, also punctures the long-held belief that light or moderate alcohol consumption is good for the heart. The researchers found no reduction in heart disease deaths among light or moderate drinkers, regardless of this health or socioeconomic status, when compared with occasional drinkers. The study defined light drinking as a mean alcohol intake of up to 20 grams a day for men and up to 10 grams daily for women. (In the United States, a standard drink is 14 grams of alcohol.) “We did not find evidence of a beneficial association between low drinking and mortality,” said Dr. Rosario Ortolá, an assistant professor of preventive medicine and public health at Universidad Autónoma de Madrid and the lead author of the paper, which was published in JAMA Network Open. On the other hand, she added, alcohol probably raises the risk of cancer “from the first drop.” The findings add to a mounting body of evidence that is shifting the paradigm in alcohol research. Scientists are turning to new methodologies to analyze the risks and benefits of alcohol consumption in an attempt to correct what some believe were serious flaws in earlier research, which appeared to show that there were benefits to drinking. © 2024 The New York Times Company

Keyword: Drug Abuse
Link ID: 29428 - Posted: 08.13.2024

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