By Dana G. Smith Many people’s brains deteriorate as they age, becoming riddled with malfunctioning proteins that result in cell death and the loss of memory and cognition. But other people’s brains remain almost perfectly intact, their thinking as sharp at 80 as it was in their 50s. A paper published Wednesday in the journal Nature provides a new potential explanation for this discrepancy, and it taps into one of the hottest debates in neuroscience: whether human brains can grow new neurons in adulthood, a phenomenon called neurogenesis. The study found that so-called super-agers — people 80 and up who have the memory ability of someone 30 years younger — had roughly twice as many new neurons as older adults with normal memory for their age, and 2.5 times more than people with Alzheimer’s disease. The research focused on an area of the brain called the hippocampus, which is important for learning and memory and is thought to be the primary birthplace of new neurons. “This paper shows biological proof that the aging brain is plastic,” even into a person’s 80s, said Tamar Gefen, an associate professor of psychiatry and behavioral sciences at the Northwestern University Feinberg School of Medicine, who contributed to the research. To look for neurogenesis in older adults, the scientists first tried to detect signs of it in the autopsied brains of young adults, age 20 to 40, who died with normal cognition. They identified genetic markers for three key types of cells: neural stem cells, neuroblasts and immature neurons. © 2026 The New York Times Company

Keyword: Neurogenesis; Alzheimers
Link ID: 30144 - Posted: 02.28.2026

Mariana Lenharo Adults whose brains still have strong neuron production seem to have better memory and cognitive function than do those in whom the ability wanes, finds a study published today in Nature1. The authors examined brain samples from deceased donors ranging from young adults to ‘super agers’ — people older than 80 with exceptional memory. She lived to 117: what her genes and lifestyle tell us about longevity They found that young and old adults with healthy cognition generated neurons, a process called neurogenesis, at high levels for their age. The team estimated that the new neurons made up only a small fraction — 0.01% — of those in the hippocampus, a brain region that’s essential for memory. By contrast, in people experiencing cognitive decline, including individuals with Alzheimer’s disease, neurogenesis seems to falter: the researchers spotted fewer developing, or immature, neurons in those brain samples. Surprisingly, a group of ‘super agers’ had an even higher number of immature neurons than did other groups, and significantly more than did those with Alzheimer’s. However, the group sizes were small, so the findings were not all statistically significant. Maura Boldrini Dupont, a neuroscientist and psychiatrist at Columbia University in New York City, says that the small size of the groups — each had ten or fewer individuals — is a reason to take the results with a grain of salt. Understanding the tools that the brain uses to generate neurons and maintain cognitive function in old age could help researchers to develop drugs that induce neurogenesis in people with cognitive decline, says co-author Orly Lazarov, a neuroscientist at the University of Illinois Chicago. © 2026 Springer Nature Limited

Keyword: Neurogenesis; Alzheimers
Link ID: 30143 - Posted: 02.28.2026

By Tim Vernimmen Steve Fleming’s research is definitely “meta” — a Greek prefix indicating self-reference. He’s a cognitive neuroscientist at University College London who studies metacognition: what we know about what we know, think about what we think, believe about what we believe. While this may seem quite philosophical and well-nigh impossible to study in the lab, he has made it his mission to measure and model it and understand where in the brain it manifests itself. Fleming explored these issues in his 2021 book, Know Thyself: The Science of Self-Awareness. In the 2024 Annual Review of Psychology, he further examined the link between metacognition and confidence: our sense of whether we have made the right decision, whether we are successful at the tasks presented to us, and whether our worldview is likely correct. Fleming’s work is casting new light on why some people seem chronically underconfident even when they’re doing just fine, and why others are entirely convinced they’re right about everything, even when there is overwhelming evidence to the contrary. In the following discussion, which has been edited for length and clarity, Fleming shared his thoughts on some of the questions that inevitably come up when our brains assess their own activity. Metacognition is quite an uncommon research topic. How did you end up studying this? I studied experimental psychology in Oxford, where I had the opportunity to work with psychologist Paul Azzopardi. He studies blindsight, a condition where, due to certain types of brain damage, people are subjectively blind but still able to perform various tasks using visual information. This presents a fascinating dissociation between conscious experience and actual functionality.

Keyword: Consciousness; Attention
Link ID: 30142 - Posted: 02.28.2026

By Nora Belblidia To the naked eye, Annie Kathuria’s experiments look a bit like tiny tufts of cotton floating in pink Petri dishes. These unassuming orbs are clusters of millions of human brain cells called brain organoids — brainstem organoids in this case — cultured in a lab in East Baltimore. Roughly a month old, the tufts are each around a millimeter wide, smaller than a coarse grain of salt. “We have about maybe 500 to 600 organoids growing,” said Kathuria, an assistant professor of biomedical engineering and neurosurgery at Johns Hopkins University. In addition to the brainstem organoids, her lab is also growing other types that correspond to different parts of the nervous system: cortical organoids, which mimic a brain’s developing cortex, and spinal cord organoids, to model the spinal nerve tissue that connects to the brain. Each of these clumps of neural tissue functions similarly to specific regions of the human brain. That similarity has led to some media coverage referring to them as “mini-brains” or “brains in a dish” — now irksome terms to many researchers in the field, some of whom also prefer the term neural organoids to brain organoids. Annie Kathuria, assistant professor of biomedical engineering and neurosurgery, in her lab at Johns Hopkins University in Baltimore. Visual: Nora Belblidia for Undark “Whatever else they are, they aren’t brains. They aren’t organized like brains. They aren’t big enough,” said Hank Greely, a Stanford University professor and expert in law and biosciences who works with researchers in the field. “But more importantly, they don’t have the right architecture.” By that he means organoids are basic parts of a whole, similar to how a broom closet or stairwell would never be considered a skyscraper.

Keyword: Development of the Brain
Link ID: 30141 - Posted: 02.28.2026

By Justin O’Hare For decades, two complementary but often siloed approaches have guided neuroscience: cellular neuroscience, which seeks to understand how individual neurons work; and systems neuroscience, which aims to uncover how networks of neurons coordinate to produce thoughts, movements and behaviors. One studies the tree; the other studies the forest. Each approach has produced tremendous advances. For instance, cellular neuroscientists have revealed how ion channels shape the electrical language of the brain, how synapses strengthen or weaken with experience and how gene expression governs neuronal function. Meanwhile, systems neuroscientists have mapped entire circuits, recorded the activity of tens of thousands of neurons during behavior and identified patterns of activity that correlate with memory, decision-making and emotion. But for all these advances, a question lingers: Are we actually any closer to understanding how the brain works? The jaw-dropping datasets produced by systems-level studies are seldom reconciled with biology, and the exquisite detail uncovered by cellular-level studies is rarely extrapolated from circuits to behavior. These disconnects don’t reflect failures of either approach. Rather, they reflect the vast intellectual and material resources that each requires. Nevertheless, the brain is a multiscale organ. It is organized across multiple hierarchical levels operating in concert, not in parallel. To unravel the brain’s deepest complexities, we need to bridge cellular and systems neuroscience. Because of recent technological advances in high-density electrical probes, genetically encoded fluorescent sensors, multiphoton imaging and high-performance computing, we are better suited to do this now than ever before. © 2026 Simons Foundation

Keyword: Learning & Memory; Brain imaging
Link ID: 30140 - Posted: 02.28.2026

Rachel Fieldhouse Alzheimer’s disease is about to become a big problem for China. Nearly 30% of all people with the condition or related forms of dementia already live in the country. And with its ageing population and falling birth rate, the burden on health and social welfare is expected to multiply dramatically in the coming decades. The Chinese government has responded with programmes and funding that are aimed at improving screening, diagnosis and treatment of Alzheimer’s disease by 2030. And the research has started to take off. Scientists have been working on new drugs and innovative — if controversial — surgical techniques. The government has also encouraged the development of drugs derived from traditional Chinese medicine. And researchers are accelerating the search for biological markers that precede the onset of Alzheimer’s disease, including genetic contributors, which could explain how the condition develops and reveal the best way to identify it early. Although the investments don’t yet match the level of funding in the United States, the improving quality and quickening pace of clinical and preclinical research has attracted attention from researchers around the world. “Maybe China is the next place that will take the lead,” says John Hardy, a neurogeneticist at the UK Dementia Research Institute in London, who is also affiliated with the Hong Kong Center for Neurodegenerative Diseases. Treating the root of the problem Nearly 17 million people in China had Alzheimer’s disease and related dementias in 2021 — about 9 in 1,000, according to a report published last year1. Projections suggest that this number could reach as high as 66 million by 2050 (see ‘Dementia’s rise’) or even exceed 100 million by then2,3. The problem is compounded by China’s low fertility rate, which means that there will be fewer people of working age to support the growing population of older individuals with debilitating conditions. © 2026 Springer Nature Limited

Keyword: Alzheimers
Link ID: 30139 - Posted: 02.25.2026

By Carl Zimmer Look at just about any vertebrate and you’ll see two eyes looking back at you. Falcons circling overhead have two eyes, just like hammerhead sharks roving through the ocean. Scientists have long puzzled over how the vertebrate eye first evolved. A pair of new studies suggest a strange beginning: Our invertebrate ancestors 560 million years ago were cyclopes, with a single eye at the top of their head, scientists now propose, that only later split in two. Charles Darwin fretted a lot about the exquisite complexity and sophistication of the vertebrate eye as he developed his theory of evolution. “The eye to this day gives me a cold shudder,” he confided to his friend, the American botanist Asa Gray, in 1860. Somehow evolution had produced the eye from many parts, such as the lens and retina, through tiny changes through the generations. Darwin couldn’t say for sure what that sequence of changes was. But he was encouraged by the diversity of simpler eyes among invertebrates. Some are mere lumps of pigment that detect light; others are simple cups lacking lenses. “When I think of the fine known gradations,” Darwin wrote to Gray, “my reason tells me I ought to conquer the cold shudder.” Yet opponents of evolution continued to cast doubt on the idea that eyes could evolve. Even in the 1990s, creationists claimed that natural selection would need many billions of years to produce an eye — far more time than life has existed on Earth. Dan-E. Nilsson, a neurobiologist at Lund University in Sweden, grew so annoyed by these claims that he estimated how long it would actually take for a patch of light-sensitive cells to evolve into an image-forming eye. “I thought, Heck, that’s an easy calculation, let’s do that,” Dr. Nilsson recalled. In 1994 he and Susanne Pelger, a colleague at Lund, concluded that an image-forming eye could evolve in just a few hundred thousand years. “It’s not precise in any way at all, but it goes to show that there is plenty of time for eyes to evolve,” Dr. Nilsson said. © 2026 The New York Times Company

Keyword: Evolution
Link ID: 30138 - Posted: 02.25.2026

By Hannah Thomasy In 1774, British physician-scientist Charles Blagden received an unusual invitation from a fellow physician: to spend time in a small room that was hotter, he wrote, “than it was formerly thought any living creature could bear.” Many people may have been appalled by this offer, but Blagden was delighted by the opportunity for self-experimentation. He marveled as his own temperature remained at 98 degrees Fahrenheit (approximately 37 degrees Celsius), even as the temperature of the room approached 200°F (about 93°C). Today, this ability to maintain a stable body temperature — called homeothermy — is known to exist among myriad species of mammals and birds. But there are also some notable exceptions. The body temperature of the fat-tailed dwarf lemur, for example, can fluctuate by nearly 45°F (25°C) over a single day. In fact, a growing body of research suggests that many more animals than scientists once appreciated employ this flexible approach — heterothermy — varying their body temperature for minutes, hours or weeks at a time. This may help the animals to persist through all sorts of dangers. “Because we’re homeotherms, we assume all mammals work the way we do,” says Danielle Levesque, a mammalian ecophysiologist at the University of Maine. But in recent years, as improvements in technology allowed researchers to more easily track small animals and their metabolisms in the wild, “we’re starting to find a lot more weirdness,” she says. The most extreme — and well-known — form of heterothermy is classic hibernation, which has been most extensively studied in critters who use it to save energy and so survive the long, cold winters of the Northern Hemisphere. These animals enter long periods of what scientists call deep torpor, when metabolism slows to a crawl and body temperature can drop to just above freezing.

Keyword: Evolution
Link ID: 30137 - Posted: 02.25.2026

By Emma Gometz Caribou, large deer that are native to the northernmost parts of the world (and sometimes called reindeer), are the only deer whose females grow antlers. In a study published today, researchers observed behavior that might explain why: female caribou appear to gnaw on shed antlers as a kind of postbirthing supplement. Caribou migrate huge distances every year between the places where they graze during the winter and the grounds where they calve in the spring. They can walk thousands of miles per year and likely have the longest terrestrial migration of any animal. Caribou mothers complete these extremely long migrations with antlers on their head and a calf in their womb. The period is very nutritionally demanding for them but culminates with a reserve stock of supplements when they need it the most. The researchers behind the new study figured this out when they observed bite marks in more than 80 percent of the 1,500 caribou antlers that littered the part of the Arctic National Wildlife Refuge in northeastern Alaska where the deer give birth. “[Caribou] are just really going after the antlers. They are highly selective,” says study co-author Joshua Miller, a paleoecologist at the University of Cincinnati. Female caribou shed their antlers just days before giving birth. Miller and co-author Madison Gaetano, a conservation paleobiologist, say that the findings suggest that female caribou are essentially banking nutrients in the form of antlers before they give birth and then gnawing on their freshly shed antlers to get a boost of protein, calcium and phosphorus they need to make up for having less time to graze as they nurse their calves. © 2025 SCIENTIFIC AMERICAN,

Keyword: Sexual Behavior
Link ID: 30136 - Posted: 02.25.2026

By Delthia Ricks Susan E. Leeman, who helped reshape scientific understanding of how the brain sends chemical signals throughout the body, did not hesitate to leave the laboratory when her research demanded it — even if it meant visiting slaughterhouses. In the late 1960s, while running a small lab at Brandeis University, she was trying to isolate a stress hormone and needed large quantities of the bovine hypothalamus, a cow’s version of the structure found deep in all mammalian brains. When supplies ran short at a local meatpacker in Boston, Dr. Leeman traveled to Chicago, home at the time to the sprawling Union Stock Yards, to secure fresh tissue. What ultimately emerged was not the hormone that she sought but an elusive chemical called Substance P. Discovered decades earlier but never fully understood, it was finally identified by Dr. Leeman in 1970 as a neuropeptide, released by cells in the brain or spinal cord in response to pain. Three years later, she identified another neuropeptide. The two discoveries established her as a leading figure in neuroendocrinology. Dr. Leeman died on Jan. 20 in Manhattan, at the home of her daughter Eve Leeman, where she had been living. She was 95. Her death was confirmed by another daughter, Jennifer Leeman. Although Substance P was identified in 1931 by Ulf von Euler and John Gaddum, researchers working in London, it was Dr. Leeman who discovered that it was a neuropeptide — a tiny, protein-like molecule released by neurons, or nerve cells in the brain and spinal cord, that transmits signals to target tissues. It was the first neuropeptide discovered in what would become a large class known as tachykinins. Dr. Leeman found that Substance P relays pain signals and amplifies the sensation of pain by triggering inflammation. It has since been linked to chronic pain syndromes, arthritis pain and migraines. © 2026 The New York Times Company

Keyword: Pain & Touch
Link ID: 30135 - Posted: 02.25.2026

By Katherine Ellison For most of her adult life, Katherine Sanders had what she calls a typical career for someone with attention deficit hyperactivity disorder. After finishing her doctoral thesis on Bronze Age Syrian mythology, she bounced between unrelated jobs. She tutored university students. She sewed Victorian corsets for bridal outfits. She designed stained glass and sold picture frames. She enjoyed the work, but none of it felt like a calling. Life got harder when she found herself juggling part-time work with caring for a spirited five-year-old. Sanders, who lives in Edinburgh, Scotland, burned meals on the stove and forgot to pick up her daughter from school. Finally, she decided to work with a coach to help her cope with her ADHD, a bedeviling condition whose hallmark symptoms are distraction, forgetfulness, restlessness and impulsivity. She began by enrolling in a digital course called Your ADHD Brain is A-OK. Like most ADHD coaches, Tracy Otsuka, the course producer, has herself been diagnosed with the disorder. Otsuka, based in Northern California, says she focuses on helping her clients shed shame as a prelude to finding their purpose and living more fulfilled lives. Participants in the self-paced course watch 26 videos and fill out worksheets designed to identify their values and strengths. Sanders says working with Otsuka led to a lightbulb moment for her. “This woman is very smart, she’s very savvy,” she says. “And she still did stuff like forget to pick her kid up from school.… She still does the same things as me.” The experience made Sanders realize that she, too, was smart but had a specific challenge she needed to learn to manage.

Keyword: ADHD
Link ID: 30134 - Posted: 02.21.2026

By Natalia Mesa Most male mammals do not dote on their young and may even attack them, but some African striped mice actively feed, groom and nuzzle their own and even others’ pups. These profound behavioral differences come down to a single gene: agouti. This gene controls pigment production in the hair or skin of many animals. But in African striped mice, it also acts as a volume knob to silence caregiving circuits in the brain, according to a study published today in Nature. “It’s remarkable that this one gene is able to lead to a dramatic change in behavior,” says Robert Froemke, professor of genetics, neuroscience and otolaryngology at New York University, who was not involved in the work. Male African striped mice that live in isolation for roughly 2 months after weaning tend to nurture pups later in life, even those that are not their own, whereas their peers that live with other mice tend to be indifferent fathers or even infanticidal, the study found. The fatherly mice express lower levels of agouti in the brain compared with their more aggressive counterparts, the study shows. “Agouti, we think, is a molecular integrator of environmental experience,” says study author Ricardo Mallarino, associate professor of molecular biology at Princeton University. Despite the fact that only about 5 percent of mammalian species show fatherly behavior, parental care may be the default mode in striped mice, the research suggests. Both males and females use the same brain circuitry to care for their young, but enhanced agouti expression in the brain suppresses these instincts in the former. © 2026 Simons Foundation

Keyword: Sexual Behavior; Aggression
Link ID: 30133 - Posted: 02.21.2026

Carlo Iacono Everyone is panicking about the death of reading. The statistics look damning: the share of Americans who read for pleasure on an average day has fallen by more than 40 per cent over the past 20 years, according to research published in iScience this year. The OECD calls the 2022 decline in educational outcomes ‘unprecedented’ across developed nations. In the OECD’s latest adult-skills survey, Denmark and Finland were the only participating countries where average literacy proficiency improved over the past decade. Your nephew speaks in TikTok references. Democracy itself apparently hangs by the thread of our collective attention span. This narrative has a seductive simplicity. Screens are destroying civilisation. Children can no longer think. We are witnessing the twilight of the literate mind. A recent Substack essay by James Marriott proclaimed the arrival of a ‘post-literate society’ and invited us to accept this as a fait accompli. (Marriott does also write for The Times.) The diagnosis is familiar: technology has fundamentally degraded our capacity for sustained thought, and there’s nothing to be done except write elegiac essays from a comfortable distance. I spend my working life in a university library, watching how people actually engage with information. What I observe doesn’t match this narrative. Not because the problems aren’t real, but because the diagnosis is wrong. The declinist position rests on a category error: treating ‘screen culture’ as a unified phenomenon with inherent cognitive properties. As if the same device that delivers algorithmically curated rage-bait and also the complete works of Shakespeare is itself the problem rather than how we decide to use it. © Aeon Media Group Ltd. 2012-2026.

Keyword: Attention; Language
Link ID: 30132 - Posted: 02.21.2026

By Meghan Bartels On March 7, 1949, researchers at the Woods Hole Oceanographic Institution (WHOI) were stationed on a boat called the R/V Atlantis that was sailing off the coast of Bermuda. They lowered a primitive underwater recording setup into the ocean, and a boxy machine more regularly found in offices began etching the sounds of the sea—a chorus of eerie howls and rustling waves—into a thin plastic disk. That disk made its way to WHOI’s archives in Massachusetts, where it sat, an overlooked relic of the earliest days of underwater acoustic recording. Fast-forward nearly eight decades, and experts at WHOI have rediscovered the recording and determined it’s probably the oldest whale recording still in existence. The likely vocalist? A humpback whale (Megaptera novaeangliae). The scientists who stumbled on the rare recording are eager to use it for science. “Data from this time period simply don’t exist in most cases,” said Laela Sayigh, a marine bioacoustician at WHOI, in a statement. “This recording can provide insight into how humpback whale sounds have changed over time, as well as serving as a baseline for measuring how human activity shapes the ocean soundscape.” The recording dates to a time when the North Atlantic Ocean’s humpback whales were struggling because of decades of commercial whaling. By 1955, the population had likely fallen below 1,000 animals, experts have since estimated. And although humpback whales are due for a thorough census, even outdated estimates suggest there are at least 20 to 25 times the number of these animals in the region today. © 2025 SCIENTIFIC AMERICAN,

Keyword: Animal Communication; Language
Link ID: 30131 - Posted: 02.21.2026

Heidi Ledford A simple blood test might one day serve as a molecular ‘clock’ that predicts not only whether someone will develop Alzheimer’s disease — but when. Blood tests are now approved for Alzheimer’s: how accurate are they? The test, published in Nature Medicine on 19 February1, is based on an abnormal form of a protein called tau that circulates in the blood, and begins to accumulate in the brains of people with Alzheimer’s well before symptoms such as memory loss appear. If validated in larger studies, the test could provide a way to intervene in the neurodegenerative disease at an earlier stage, when treatment is more likely to be effective. It could also provide a measurable biological marker, or ‘biomarker’, to make clinical trials of potential Alzheimer’s disease treatments easier and cheaper. “Predicting if and when patients are likely to develop Alzheimer’s symptoms could be useful in designing trials of interventions to prevent or delay symptom onset,” says Howard Fink, a physician at the Minneapolis Veterans Affairs Health Care System in Minnesota. But until further studies are done, people should not take the test themselves, says Suzanne Schindler, a neurologist at Washington University School of Medicine in St. Louis, Missouri, and lead author of the study. (In-home blood tests for the form of tau that the study focuses on are available to consumers.) “At this point, we do not recommend that any cognitively unimpaired individuals have any Alzheimer’s disease biomarker test,” Schindler adds. Abnormal tau proteins can form tangled fibres that disrupt communication among the brain’s nerve cells. Brain-imaging tests that detect tangled tau are sometimes used when diagnosing Alzheimer’s, and preliminary studies suggest that such tests might also be able to predict when a person’s Alzheimer’s symptoms will appear2,3. © 2026 Springer Nature Limited

Keyword: Alzheimers
Link ID: 30130 - Posted: 02.21.2026

By Meghan Rosen Ozempic’s key ingredient may act directly on cartilage to repair creaky joints. In mice and people, semaglutide can ease symptoms of the joint disease osteoarthritis and thicken the cartilage pillowed between bones, researchers report February 9 in Cell Metabolism. Thicker cartilage suggests the tissue is being rebuilt, says Di Chen, a physician and biologist at Shenzhen University of Advanced Technology in China. “That’s a good thing,” he says. “That’s the key thing.” More cartilage means more cushion, which means less bone-on-bone grinding and less pain. Osteoarthritis is the most common form of arthritis, affecting more than 500 million people worldwide. The disease can affect the hands, knees, hips and other joints, causing severe pain as cartilage wears away and tissues inflame. There’s no cure, and no medications that prevent it from becoming worse. Doctors can only help patients try to manage pain, Chen says. Scientists think weight loss can help alleviate symptoms by reducing the load on joints. That’s why semaglutide, the smash weight loss drug in Ozempic and Wegovy, is considered a contender for osteoarthritis treatment. And indeed, in 2024, a clinical trial in people with obesity reported that the drug improved joint pain and function. Doctors assumed those benefits were due to weight loss, Chen says. His team wasn’t so sure. The researchers conducted a similar study in mice with a form of osteoarthritis. One group received semaglutide, the other did not. In the drug-free mice, Chen’s team restricted food intake to match that of the semaglutide group. Both groups shed weight, but only the treated mice saw joint-based benefits. These mice had less pain, less broken-down cartilage and more cartilage growth, the team found. The results suggest that weight loss isn’t driving semaglutide’s benefits. © Society for Science & the Public 2000–2026.

Keyword: Neuroimmunology; Obesity
Link ID: 30129 - Posted: 02.21.2026

By Chris Simms Some sex differences in brain-connectivity patterns become more pronounced with age, according to new research. Researchers studying brain-imaging data from people aged between 8 and 100 found that sex differences in the brain’s connections are minimal in early life, but then increase drastically at puberty; some of these differences continue to grow throughout adult life. The study was published as a preprint on bioRxiv1, and has not yet been peer reviewed. The work could help us to understand why men and women have different likelihoods of developing some mental-health disorders — and perhaps give insight into treating them, say the researchers. For example, women are about twice as likely as men to develop anxiety or depression2, and boys are about four times more likely to be diagnosed with autism spectrum disorder than girls3. “We are very excited about this study, which to our knowledge is the first one to compare how sex differences in brain networks evolve over the lifespan,” says Amy Kuceyeski, a computational neuroimager at Weill Cornell Medicine in Ithaca, New York. However, some neuroscientists who spoke to Nature aren’t convinced that the differences found between male and female brains are due to sex, and say the study does not address differences in gender roles, which are known to be important factors when researching brain mechanisms of health and disease. Human brains do not belong in distinct ‘female’ and ‘male’ categories, says Daphna Joel, a neuroscientist at the University of Tel Aviv in Israel, referring to a 2015 study she co-authored, which suggests that each human brain is a mosaic of features, some of which are more common in men, others in women4. © 2026 Springer Nature Limited

Keyword: Sexual Behavior; Development of the Brain
Link ID: 30128 - Posted: 02.18.2026

Jon Hamilton A little brain training today may help stave off Alzheimer's disease and other forms of dementia for at least 20 years. That's the conclusion of a study of older adults who participated in a cognitive exercise experiment in the 1990s that was designed to increase the brain's processing speed. The federally funded study of 2,802 people found that those who did eight to 10 roughly hourlong sessions of cognitive speed training, as well as at least one booster session, were about 25% less likely to be diagnosed with dementia over the next two decades. "We now have a gold-standard study that tells us that there is something we can do to reduce our risk for dementia," says Marilyn Albert, an author of the study and a professor of neurology at Johns Hopkins University School of Medicine. "It's super-exciting to see that these effects are still holding 20 years out," says Jennifer O'Brien, an associate professor of psychology at the University of South Florida who was not involved in the research. The study appears in the journal Alzheimer's & Dementia: Translational Research & Clinical Interventions. The result is good news for people like George Kovach, 74, who started doing cognitive speed training a decade ago. This illustration shows a pink human brain with stick legs and stick arms. The pink stick arms are holding up a black barbell with black disk-shaped weights on each end. © 2026 npr

Keyword: Alzheimers; Learning & Memory
Link ID: 30127 - Posted: 02.18.2026

Ian Sample Science editor People with major depressive disorder can see a rapid and lasting improvement after a single dose of the psychedelic drug dimethyltryptamine (DMT) when it is combined with psychotherapy, doctors have said. A small clinical trial involving 34 people found that psychedelic-assisted therapy prompted a swift reduction in depressive symptoms that endured long after the drug had worn off, with some still feeling the benefits six months later. “There is an immediate antidepressant effect that is significantly sustained over a three-month period and that’s exciting because this is one session with a drug, embedded in psychological support,” said Dr David Erritzoe, a psychiatrist at Imperial College London and lead investigator on the trial. Although preliminary, the results add to a growing body of evidence that psychedelic drugs, when coupled with psychotherapy, could help to alleviate depression in the millions of people worldwide who do not respond to existing antidepressants or therapies. An estimated 100 million people worldwide have treatment-resistant depression, defined as a major depressive disorder that has not responded to at least two antidepressants. About half are unable to perform routine daily tasks. The trial, reported in Nature Medicine, focused on people with moderate to severe treatment-resistant depression. One half received a single 21.5mg dose of DMT infused into a vein over 10 minutes. The other half received a placebo infused the same way. All of the participants had psychotherapy and follow-up assessments. © 2026 Guardian News & Media Limited

Keyword: Depression; Drug Abuse
Link ID: 30126 - Posted: 02.18.2026

By Elizabeth Preston On the island of Golem Grad in North Macedonia, visitors may see a chain of tortoises mounting each other like a slow-moving, libidinous locomotive. It used to strike Dragan Arsovski, an ecologist at the Macedonian Ecological Society, as funny. Now that he knows what’s really going on, he isn’t laughing. This uninhabited island in a country that once was part of Yugoslavia is crawling with around 1,000 Hermann’s tortoises — especially males. They pursue mates aggressively, making life unhealthy and short for the island’s scarce females. Some of those females even die by walking off the island’s cliffs. In a paper published last month in the journal Ecology Letters, researchers have found that the relentless males are driving their population to extinction. The island, in Lake Prespa, has a forested plateau encircled by sheer cliffs. When Dr. Arsovski started studying the salad-plate-size tortoises in 2008, “it was quite a dense and seemingly prosperous population,” he said. But for some reason, there were far more adult males than females — 19 males for every female on the plateau, at the latest count. He and his colleagues documented how the males seemed to manage their carnal instincts by mounting each other. Then, after many years of study, Dr. Arsovski realized that the females were undersized and dying young. He also realized those once-comical copulatory trains were made up of many males pursuing just one female. When the female tired, the train would become a frenzied heap of reptiles. “She’s literally buried by males,” Dr. Arsovski said. He and his co-authors wrote that as part of the tortoises’ courtship, they “bump, bite (sometimes to the point of blood loss), mount and finally vigorously poke fleeing females” with a sharp tail tip. Three-quarters of the island’s females had genital injuries. © 2026 The New York Times Company

Keyword: Aggression; Sexual Behavior
Link ID: 30125 - Posted: 02.18.2026