By Claudia López Lloreda A previously unrecognized population of fibroblasts seals off the base of the choroid plexus—the network of blood vessels and cerebrospinal-fluid-producing epithelial cells that line the ventricles—from the cerebrospinal fluid (CSF) and the rest of the brain, a new study in mice shows. The newly identified barrier provides an added layer of protection that is distinct from the well-known blood-brain barrier and the one that the epithelial cells form between the blood and the CSF. The findings help settle a long-standing debate about whether there was a blind spot in the choroid plexus that gave the periphery access into the brain, says Britta Engelhardt, professor of immunobiology at the University of Bern, who was not involved in the work. “Some [scientists] speculated that there is a leak, like an opening, a secret window into the brain, and others said, ‘No, there must be a barrier that we have overlooked.’ And it’s very obvious now.” Fibroblasts at the base of the choroid plexus, connected by adherens and tight junction proteins, cluster together around blood vessels and form a sealed barrier in mice, the researchers found. This structure represents a crucial component of compartmentalization in the choroid plexus, Engelhardt says. The cells were also present in human postmortem brain samples. Similar to other barriers, the seal becomes leaky in response to inflammation triggered by lipopolysaccharide, a component of the bacterial cell wall, and it may coordinate immune cell crossing from the blood into the brain, the study also showed. The work was published in February in Nature Neuroscience. © 2026 Simons Foundation

Keyword: Neuroimmunology; Drug Abuse
Link ID: 30190 - Posted: 04.04.2026

By Diana Kwon Human minds often wander. Whether we’re busy at work, doing chores or exercising, our thoughts frequently shift away from the task at hand. These spontaneous thoughts sometimes turn toward sensations in the body, such as our heartbeat or breath, and that could affect our immediate emotional state and long-term mental health, researchers report March 25 in Proceedings of the National Academy of Sciences. Many studies focus on thinking about memories, events and other people, what scientists consider the cognitive aspects of mind wandering, says Micah Allen, a neuroscientist at Aarhus University in Denmark. This research suggests that mind wandering plays an important role in planning, learning, creativity and other important mental processes. It has also been linked to negative emotions and some, such as obsessively ruminating on past mistakes, may contribute to depression, attention-deficit/hyperactivity disorder and other mental illnesses. Do you share our vision for a healthier, happier world through science? But how the mind might drift to bodily sensations, what some researchers call “body wandering,” and its effects have largely been overlooked, Allen says. He and colleagues had 536 people lie still in a magnetic resonance imaging scanner and then complete a questionnaire about what was on their minds during that time. In addition to the typical content of daydreams, such as memories, plans or social interactions, participants reported paying attention to sensations in their body, such as their breathing, heartbeats and bladder. The team also found evidence of this in the MRI scans: Body wandering appeared to have a distinct brain signature from that of “cognitive” mind wandering. © Society for Science & the Public 2000–2026.

Keyword: Stress; Attention
Link ID: 30188 - Posted: 04.04.2026

By Ellen Barry When Cohen Miles-Rath walks into his father’s house, the history of his psychosis is right there in front of him. There is the place where he was standing when he received a cryptic message on his phone: The devil had entered his father’s body. There is the drawer where he spotted a knife whose handle was white — the color of God! There is the floor where, as they grappled over the knife, Cohen bit off part of his father’s earlobe, and blood spattered over both of them. There is the spot where, pinned to the floor, Cohen reached up with the knife and slashed wildly at his father’s throat. The violence lasted seconds but changed his whole life. With voices still racketing in his head, Cohen found himself in jail, facing charges of second-degree assault and criminal mischief, felonies punishable by up to 10 years in prison. Stunned and bleeding, his father had pressed charges, and taken out a restraining order against him. But Cohen hadn’t killed him. In the years that followed, he had the feeling that he had walked right up to the edge of a chasm. About 300 times a year in the United States, a child kills a parent, making up around 2 percent of all homicides. A large portion of these cases involve people like Cohen: young men with severe mental illness who are living at home. When mounting symptoms of psychosis make school or work impossible, parents are the support system of last resort. Paranoid delusions can cruelly invert that logic, turning people against the figure closest to them. © 2026 The New York Times Company

Keyword: Schizophrenia; Aggression
Link ID: 30186 - Posted: 04.01.2026

By Andrew Jacobs Over the past two years, Australia, a country long known for its strict drug laws, has been allowing psychiatrists to treat post-traumatic stress disorder with MDMA, the chemical compound better known as Ecstasy or molly. The early results have been striking, researchers say, with more than half of patients who received MDMA along with psychotherapy reporting significant relief from PTSD. Just as notably, Australian drug regulators have not recorded any serious adverse events among the nearly 200 patients who have been through the program, which includes up to three dosing sessions with MDMA, a synthetic stimulant that promotes empathy, emotional connection and feelings of euphoria. That data point is especially relevant given the contentious debate in the United States over the safety of MDMA — one that in 2024 helped sink the prospects for MDMA therapy at the Food and Drug Administration. “Compared to conventional treatments, the outcomes we’re seeing to date with MDMA-assisted therapy have been extraordinary,” said Dr. Ranil Gunewardene, a psychiatrist in Sydney who has treated more than 40 patients since the Australian regulators created a legal pathway for the drug. But Australia’s experiment with psychedelic medicine also highlights the limitations and constraints that the nascent field is likely to face as it gains wider attention from regulators and practitioners. Because Australia is the first country to legalize and regulate MDMA therapy, researchers have been especially eager for real-world data about a drug that has been pejoratively associated with rave culture. © 2026 The New York Times Company

Keyword: Stress; Drug Abuse
Link ID: 30177 - Posted: 03.25.2026

By Sarah Scoles When George W. Maschke applied to work for the FBI in 1994, he had already held a security clearance for over 11 years. The government had deemed him trustworthy through his career in the Army. But soon, a machine and a man would not come to the same conclusion. His application to be a special agent had passed initial muster. And so, in the spring of 1995, according to his account, he found himself sitting across from an FBI polygraph examiner, answering questions about his life and loyalties. He told the truth, he said in an interview with Undark. But in a blog post on his website, he recalled the examiner told him that the polygraph machine — which measured some of Maschke’s physiological responses — indicated that he was being deceptive about keeping classified information secret, and about his contacts with foreign intelligence agencies. After a failed polygraph exam in which he says he told the truth, George Maschke eventually co-founded the advocacy website AntiPolygraph.org. “My entire career prospects were basically shattered,” said Maschke. “How could I have told the truth and failed the polygraph?” He wanted an answer. And so soon after his failed exam, he said he went to the research library to try to learn more about what had transpired between his body, that machine, and the measuring man. Further spurred by another negative polygraph experience, the resulting deep dive on polygraphs and examination methods eventually led him to co-found the advocacy website AntiPolygraph.org. “When I had my polygraph experience, I had no one to talk to,” said Maschke, who went on to work as a legal translator in the Netherlands. He hoped his public-facing website meant others wouldn’t have that experience.

Keyword: Stress
Link ID: 30175 - Posted: 03.25.2026

By Holly Barker Astrocytes—but not neurons—in the amygdala encode anxiety-like states in mice, according to a paper published today in Neuron. The findings suggest that the cells—which are altered in people with some neuropsychiatric conditions, including autism—contribute to mental health difficulties documented in such groups. “In a very sophisticated way, the [study] shows that astrocytes are these core computational cells for highly complicated behaviors,” says Michael Wheeler, assistant professor of neurology at Harvard University, who did not contribute to the new work. “Astrocytes are understanding and signaling computations in these circuits.” Violent movies and other stressful stimuli activate the amygdala, human imaging studies have shown. And in mice, neurons in the basolateral amygdala are active when the animals are placed in exposed environments, which they find aversive, previous research has found. But that neuronal activity appears to mark shifts between defensive and exploratory behaviors rather than tracking anxiety-related ones, according to a later study. The new findings suggest that astrocytes not only help neurons to regulate anxiety—as previous studies have shown—but “instruct local neurons from the top down,” says study investigator Ciaran Murphy-Royal, associate professor of neuroscience at the University of Montreal. The cells’ activity appears to function as a “safety signal,” that relays danger to other brain regions, he says. Murphy-Royal and his colleagues used calcium imaging to measure astrocytic activity in the mouse basolateral amygdala. Calcium release tracked with freezing, hesitancy and other behaviors reminiscent of anxiety as mice investigated various environments, the team found. In the elevated plus maze, for example, astrocyte activity rose when the rodents explored an open arm of the maze and surged whenever mice peeked over the edge of the suspended setup. © 2026 Simons Foundation

Keyword: Emotions; Glia
Link ID: 30174 - Posted: 03.25.2026

By Simon Makin A brain repair kit that helps yaks and other animals naturally cope with low oxygen levels at high altitudes may point to a new way to treat brain diseases such as multiple sclerosis. In mice with brain damage that mimics MS, the kit’s tools lessened signs of damage in young mice exposed to low oxygen and improved symptoms of MS in adult mice, researchers report March 13 in Neuron. Previous research found that animals living on the Tibetan Plateau, such as yaks and antelopes, carry a mutation in a gene called Retsat. Their lowland counterparts lack the mutation, leading scientists to suspect that it helps protect the brain in low-oxygen environments. “People usually think it’s because of better lung capability, but I wondered whether evolutionary adaptation changes the brain,” says Liang Zhang, a neuroscientist at Shanghai Jiao Tong University. In particular, he was intrigued that these animals have normal white matter in their brains. White matter makes up about half the brain; it consists of bundles of nerve fibers that allow different brain regions to communicate. This neural wiring is wrapped in myelin, a fatty substance that ensures nerve fibers conduct signals efficiently. In MS, the immune system attacks myelin, leading to neurological symptoms and problems with balance and coordination. Myelin production requires a lot of energy, which the brain gets from oxygen. Low oxygen levels, known as hypoxia, can therefore disrupt myelination. During gestation, such disruption can lead to conditions such as cerebral palsy in newborns. © Society for Science & the Public 2000–2026.

Keyword: Multiple Sclerosis; Neuroimmunology
Link ID: 30160 - Posted: 03.14.2026

By Viviane Callier The difference between a doting dad and a deadbeat one may come down to a molecular switch in the brain — at least in African striped mice. Boosting activity of a particular gene in part of the brain known for regulating maternal care turned nurturing males into standoffish ones and even, in some cases, into mouse pup killers, researchers report February 18 in Nature. The findings reveal how social context can alter gene activity in the brain and thereby shape male caregiving. Male caregiving is prevalent in fish and amphibians, suggesting that it is a very ancient behavior in vertebrates. Among mammals, however, fewer than 5 percent of species have fathers that stick around to raise their young. Male African striped mice (Rhabdomys pumilio) are one of the exceptions to the rule, though they vary a lot in their nurturing tendencies, making them an ideal species in which to study the factors that influence this behavior. Some look after the young and groom them; others ignore the pups or even attack them. The same male could become aggressive or doting. To understand that behavior, comparative neurobiologist Forrest Rogers and his colleagues observed the mice’s social environment. In laboratory settings, group-housed males tended to be aggressive toward mouse pups when introduced to them. But surprisingly, when these males were moved to be housed alone, they became very paternal. “I thought clearly something must be wrong, because all the work we know of in mice and rats is that if you socially isolate them, they become very anxious and often not the most caring of individuals,” says Rogers, of Princeton University. But the lone African striped male mice didn’t seem anxious at all. © Society for Science & the Public 2000–2026.

Keyword: Sexual Behavior; Aggression
Link ID: 30159 - Posted: 03.14.2026

By Robert Draper The hallucinations began the moment I lay back onto the mat and pulled the mask over my eyes. Oh, I instantly thought, this is not at all what I expected. The first images were assembled like a film strip, a sharply focused Technicolor row of strong, grim-faced men who appeared to be some sort of tribal chiefs. Within seconds, a green tint covered their faces, which then dissolved, replaced by images of conflict. Bodies strewed across a battlefield. Starving children. They, too, dissolved. A pile of rocks took shape. From the pile, several long, dark snakes slithered out. This could be unpleasant, I thought. A crackling sensation coursed through my entire body, as if all my neurons were firing — not in any way painful, but also inescapable. I could feel my hands sweating. My ears buzzed, and it wasn’t long before I heard the murmuring voices of people who weren’t there, followed by the sound of puking from people who were. There were 11 of us in the treatment room, in a basement in a cottage that overlooked the Pacific Ocean just south of Tijuana, Mexico, where ibogaine — a Schedule I drug in the United States — is legal. It was the night before Thanksgiving. We all had our reasons for coming to the treatment clinic called Ambio Life Sciences. Several in the group were veterans suffering from PTSD, traumatic brain injury, substance abuse or some combination of those. A sex-crimes detective had been in a terrible car accident and lost much of her short-term memory. A Marine veteran and blueberry farmer in Georgia was quietly drinking his life away. And there was Erin, a Texas-based corporate consultant who had suffered trauma that began in childhood and continued in the workplace. Erin’s mat was next to mine at the far end of the treatment room. Because we were the only two in the group not to throw up during the 10-hour experience, we later referred to ours as the Quiet Corner. The drug is derived from the Tabernanthe iboga plant, found mainly in Gabon in central Africa. The powerful hallucinogen has long been used there in the initiation ritual that is part of the Bwiti spiritual tradition, involving an intense all-night group ceremony of dance and music and fire-keeping that culminates in a trancelike state. © 2026 The New York Times Company

Keyword: Stress; Drug Abuse
Link ID: 30156 - Posted: 03.11.2026

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

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 Simon Makin Positive thinking may boost the body’s defenses against disease. Increasing activity in a brain region that controls motivation and expectation, specifically the brain’s reward system, is linked with making more antibodies after receiving a vaccine. The finding suggests these boosts were related to the placebo effect, researchers report January 19 in Nature Medicine. “Placebo is a self-help mechanism, and here we actually harness it,” says Talma Hendler, a neuroscientist at Tel Aviv University. “This suggests we could use the brain to help the body fight illness.” The work is important because it “is first-in-human evidence of a relationship between brain reward systems and immune function,” says Tor Wager, a neuroscientist at Dartmouth College in Hanover, N.H., who was not involved in the study. The study was not designed to test vaccine effectiveness. Larger studies, including more complete immune assessments, will be required to test this association as a medical intervention. Scientists have found many links between the brain and bodily health. Both negative and positive mental states can affect the immune system, and studies in rodents have suggested that the brain’s reward network is involved in these effects. To find out if the same circuitry was at play in humans, Hendler and colleagues trained healthy volunteers to regulate their brain activity using neurofeedback, a technique that uses brain imaging to show users the activity of the area they are trying to boost. The team randomly assigned 85 participants to receive training aimed at increasing activity in either their reward network or a different network, or to receive no training. © Society for Science & the Public 2000–2026.

Keyword: Neuroimmunology
Link ID: 30099 - Posted: 01.31.2026

By Alessio Cozzolino After a heart attack, the heart “talks” to the brain. And that conversation may make recovery worse. Shutting down nerve cells that send messages from injured heart cells to the brain boosted the heart’s ability to pump and decreased scarring, experiments in mice show. Targeting inflammation in a part of the nervous system where those “damage” messages wind up also improved heart function and tissue repair, scientists report January 27 in Cell. “This research is another great example highlighting that we cannot look at one organ and its disease in isolation,” says Wolfram Poller, an interventional cardiologist at Massachusetts General Hospital and Harvard Medical School who was not involved in the study. “And it opens the door to new therapeutic strategies and targets that go beyond the heart.” Someone in the United States has a heart attack about every 40 seconds, according to the U.S. Centers for Disease Control and Prevention. That adds up to about 805,000 people each year. A heart attack is a mechanical problem caused by the obstruction of a coronary artery, usually by a blood clot. If the blockage lasts long enough, the affected cells may start to die. Heart attacks can have long-term effects such as a weakened heart, a reduced ability to pump blood, irregular heart rhythms, and a higher risk of heart failure or another heart attack. Although experts knew from previous research that the nervous and immune systems could amplify inflammation and slow healing, the key players and pathways involved were unknown, says Vineet Augustine, a neurobiologist at the University of California, San Diego. © Society for Science & the Public 2000–2026

Keyword: Neuroimmunology
Link ID: 30098 - Posted: 01.28.2026

By Joshua P. Johansen Growing up in the 1980s in Santa Cruz, California, where redwood-covered mountains descend to the rocky edge of the Pacific, might sound idyllic. But in the dark wake of the drug-fueled ’70s, the beach town could also be frightening. There was a bully at my high school who once chased me down the street threatening to hurt me. Unsurprisingly, catching sight of him in the hallways or at the skate park filled me with dread. Just walking past his house would trigger a wave of anxiety. Yet if I saw him in class, with teachers present, I felt more at ease. How did my brain know to fear him only in specific circumstances? More broadly, how did I infer emotional significance from the world around me? The fact that I or anyone can make these judgments suggests that emotion arises from an internal model in the brain that supports inference, abstraction and flexible, context-dependent evaluations of threat or safety. These model-based emotion systems helped me infer danger from otherwise innocuous features of the environment, such as the bully’s house, or to downgrade my alarm, as I did when an adult was present. Understanding the neural basis of emotion is a central question in neuroscience, with profound implications for the treatment of anxiety, trauma and mood disorders. Yet the field remains divided over what emotions are and how they should be defined, limiting progress. On one side are neurobiologists focused on the neural underpinnings of simple learned and innate defensive behaviors. On the other are psychological theorists who view emotions as subjective experiences arising from complex conceptual brain models of the world that are unique to humans. This divide fuels persistent arguments over whether emotion should be defined primarily as a conscious state or not. Though subjective feelings are undeniably important, limiting our definitions to conscious phenomena prevents us from studying the underlying mechanisms in nonhuman species. To move forward, we need to identify the conserved neural processes that support higher-order, internal-model-based emotional experiences across species, regardless of whether they rise to consciousness. © 2026 Simons Foundation

Keyword: Emotions; Consciousness
Link ID: 30096 - Posted: 01.28.2026

Heidi Ledford For decades, researchers have noted that cancer and Alzheimer’s disease are rarely found in the same person, fuelling speculation that one condition might offer some degree of protection from the other. Now, a study in mice provides a possible molecular solution to the medical mystery: a protein produced by cancer cells seems to infiltrate the brain, where it helps to break apart clumps of misfolded proteins that are often associated with Alzheimer’s disease. The study, which was 15 years in the making, was published on 22 January in Cell1 and could help researchers to design drugs to treat Alzheimer’s disease. “They have a piece of the puzzle,” says Donald Weaver, a neurologist and chemist at the Krembil Research Institute at the University of Toronto in Canada, who was not involved in the study. “It’s not the full picture by any stretch of the imagination. But it’s an interesting piece.” Alzheimer’s mystery Weaver has been interested in that puzzle ever since he began his medical training, when a senior pathologist made an offhand comment: “If you see someone with Alzheimer’s disease, they’ve never had cancer.” The remark stuck with Weaver over the years as he diagnosed thousands of people with Alzheimer’s disease. “I can’t remember a single one that has had cancer,” he says. Epidemiological data do not draw such a clear divide, but a 2020 meta-analysis of data from more than 9.6 million people found that cancer diagnosis was associated with an 11% decreased incidence of Alzheimer’s disease2. It has been a difficult relationship to unpick: researchers must control for a variety of external factors. For example, people might die of cancer before they are old enough to develop symptoms of Alzheimer’s disease, and some cancer treatments can cause cognitive difficulties, which could obscure an Alzheimer’s diagnosis. © 2026 Springer Nature Limited

Keyword: Alzheimers; Stress
Link ID: 30092 - Posted: 01.24.2026

By Darren Incorvaia Much like his ninja namesake, Naruto the white-lipped peccary was a bit of a loner. Named after the titular character from a popular manga and anime, Naruto was the youngest male and one of the least social in his group of 17 peccaries, all of whom were born and raised in captivity at the Laboratory of Applied Ethology at the State University of Santa Cruz in Ilhéus, Brazil. Destined for reintroduction into Brazil’s Estação Veracel Private Natural Heritage Reserve and the Pau-Brasil Ecological Station, the peccaries were each given a personality test of sorts by lab researchers. The piglike mammals were video recorded as they went about their daily lives, resulting in 17 hours’ worth of behavioral data. Their aggressive actions, friendly touches and moments of exploration were tallied so that the peccaries could be ranked in traits such as boldness and sociability. The goal was to determine whether an individual peccary’s behavioral traits influenced its survival when released into the wild. White-lipped peccaries (Tayassu pecari) are listed as vulnerable by the International Union for Conservation of Nature, or IUCN. In Brazil, the size of the species’ historical range had plunged by 60 percent by 2020, and past efforts to reintroduce them had met limited success. Around the globe, scientists are increasingly recognizing how a reintroduced animal’s personality can impact how both individuals and groups fare in the wild. Such work is part of a growing trend to infuse the study of personality, and how it affects behavior, into conservation. When working with wild animals and tight budgets, personality tests may not always be possible. But understanding animal personality could help conservationists choose which individuals stand the best chance of surviving — helping to restore populations threatened with extinction. © Society for Science & the Public 2000–2026.

Keyword: Emotions; Evolution
Link ID: 30083 - Posted: 01.17.2026

Lynne Peeples Sometimes the hardest part of doing an unpleasant task is simply getting started — typing the first word of a long report, lifting a dirty dish on the top of an overfilled sink or removing clothes from an unused exercise machine. The obstacle isn’t necessarily a lack of interest in completing a task, but the brain’s resistance to taking the first step. Now, scientists might have identified the neural circuit behind this resistance, and a way to ease it. In a study1 published today in Current Biology, researchers describe a pathway in the brain that seems to act as a ‘motivation brake’, dampening the drive to begin a task. When the team selectively suppressed this circuit in macaque monkeys, goal-directed behaviour rebounded. “The change after this modulation was dramatic,” says study co-author Ken-ichi Amemori, a neuroscientist at Kyoto University in Japan. The motivation brake, which can be particularly stubborn for people with certain psychiatric conditions, such as schizophrenia and major depressive disorder, is distinct from the avoidance of tasks driven by risk aversion in anxiety disorders. Pearl Chiu, a computational psychiatrist at Virginia Tech in Roanoke, who was not involved in the study, says that understanding this difference is essential for developing new treatments and refining current ones. “Being able to restore motivation, that’s especially exciting,” she says. Motivated macaques Previous work on task initiation has implicated a neural circuit connecting two parts of the brain known as the ventral striatum and ventral pallidum, both of which are involved in processing motivation and reward2,3,4. But attempts to isolate the circuit’s role have fallen short. Electrical stimulation, for example, inadvertently activates downstream regions, affecting motivation, but also anxiety. © 2026 Springer Nature Limited

Keyword: Learning & Memory; Emotions
Link ID: 30079 - Posted: 01.14.2026

By Natalia Mesa Nestled in the ventromedial nucleus of the hypothalamus lies a cluster of neurons that can make otherwise mild-mannered mice fly into a rage. Stimulating these neurons, as if flipping a switch, prompts male mice to attack their cagemates. The optogenetic manipulation of these and other specialized hypothalamic neurons, starting in the early 2010s, supported the long-standing idea that distinct cell types act as an “on” switch for different innate behaviors. But it has proved challenging to disentangle the neural signals that underlie those innate behaviors from ones that drive an animal’s internal state—such as anger, hunger or sexual arousal. Mounting evidence suggests that the hypothalamus also gives rise to these internal states, which can shape innate perceptions and behaviors. Rather than triggering an innate behavior, a specific pattern of population activity encodes the intensity and duration of anger and sexual arousal, according to four studies published within the past three years. This work is “revolutionary for the hypothalamus community,” says Tatiana Engel, associate professor of computational neuroscience at the Princeton Neuroscience Institute, who was not involved in the studies. It upends the notion that the neurons in the hypothalamus merely act as a simple switchboard, Engel says. Instead, local computations in the hypothalamus keep track of the animal’s internal state and influence its behavior, the studies suggest. The hypothalamic signals that encode the intensity and duration of aggression and sexual arousal can be represented by a mathematical model called a line attractor, the four studies show. © 2026 Simons Foundation

Keyword: Emotions; Evolution
Link ID: 30073 - Posted: 01.10.2026

By Sachin Rawat One can spend hours looking at a calm sunset or a clear night sky. These scenes are not only effortless on the eyes — they may also be easy on the brain. People tend to like visual stimuli that require little cognitive effort to process, researchers report in the December PNAS Nexus. The brain is the most energy-guzzling organ in the body, and visual processing alone accounts for nearly half of its energy use. Researchers have long studied how the visual system conserves energy. But the new study addresses the question from a different perspective. “Not only is the visual system optimized for efficiency, but we might have aesthetic preferences for stimuli that are efficient to process,” says Mick Bonner, a neuroscientist at Johns Hopkins University who was not involved in the study. Neuroscientist Dirk Bernhardt-Walther of the University of Toronto and his colleagues suspected that such preferences could have evolved as cognitive shortcuts, helping organisms avoid excessive effort as they navigate their environment. To probe the energy consumed in visual processing, the researchers turned to an existing functional MRI dataset, in which four individuals viewed 5,000 images while their brain activity was monitored. Measurements of oxygen consumption in different parts of the brain provided an indicator of metabolic activity. The team also ran these images through an artificial neural network trained on object and scene recognition, using the proportion of activated “neurons” as a proxy for metabolic expense. The researchers then compared these metabolic cost estimates — both human and artificial — to the images’ aesthetic ratings, gathered from more than 1,000 online survey respondents who scored each picture on a five-point scale. In both cases, the metabolic effort required to process the images was inversely proportional to their aesthetic ratings. © Society for Science & the Public 2000–2026.

Keyword: Vision; Emotions
Link ID: 30072 - Posted: 01.10.2026

By Carl Zimmer If you live in the United States, chances are you’re familiar with the game rock-paper-scissors. You put out your hand in one of three gestures: clenching it in a fist (rock), holding it out flat (paper) or holding up two fingers in a “V” (scissors). Rock beats scissors, scissors beat paper and paper beats rock. Americans by no means have a monopoly on the game. People play it around the world in many variations, and under many names. In Japan, where the game has existed for thousands of years, it’s known as janken. In Indonesia, it’s known as earwig-man-elephant: The elephant kills the man, the man kills the earwig and the earwig crawls up through the elephant’s trunk and eats its brain. The game is so common that it exists beyond our own species. Over millions of years, animals have evolved their own version of rock-paper-scissors. For them, winning the game means passing down their genes to future generations. A study published on Thursday in the journal Science reveals the hidden biology that makes the game possible — and shows how it may be an important source of nature’s diversity. The first clues that nature also played rock-paper-scissors emerged three decades ago in the dry hills outside Merced, Calif. Barry Sinervo, a biologist then at Indiana University, studied the common side-blotched lizard there. He would mark the lizards — named for the dark blue or black spot on their side, just behind the front leg — release them into the tall grass and catch the survivors to check up on them in later years. Dr. Sinervo, who later joined the faculty at the University of California, Santa Cruz, and who died in 2021, grew fascinated by the strange mating habits of the lizards. At the start of every breeding season, the males developed one of three colors on their throats: blue, orange or yellow. And depending on their color, the males behaved differently. © 2026 The New York Times Company

Keyword: Aggression; Animal Communication
Link ID: 30071 - Posted: 01.07.2026