By Max Kozlov Joylessness triggered by stress creates a distinct brain signature, according to research in mice1. The study also reveals one brain pattern that seems to confer resilience to stress — and another that makes stressed animals less likely to feel pleasure, a core symptom of depression. These findings, published today in Nature, offer clues as to how the brain gives rise to anhedonia, a resistance to enjoyment and pleasure. The results also provide a new avenue for treating the condition — if the findings are validated in humans. “Their approach in this study is spot on,” says Conor Liston, a neuroscientist at Weill Cornell Medicine in New York City, who was not involved in the work. The experiments fill “a big gap”, he says. “Anhedonia is something we don’t understand very well.” More than 70% of people with severe depression experience anhedonia, which is also common in those with schizophrenia, Parkinson’s disease and other neurological and psychiatric conditions. The symptom is notoriously difficult to treat, even in those taking medication, Liston says. “Anhedonia is something that patients care about the most, and feel like it’s least addressed by current treatments,” he says. To understand how the brain gives rise to anhedonia, Mazen Kheirbek, a systems neuroscientist at the University of California, San Francisco, and his colleagues studied mice that had been placed under stress by exposure to larger, more aggressive mice. Typically, mice have a sweet tooth and prefer sugar water over plain water if given the option. But some stressed mice instead preferred plain water — which Kheirbek and his colleagues interpreted as a rodent version of anhedonia. Other mice subjected to the same stress preferred the sugar water. The authors labelled these animals ‘resilient’. © 2024 Springer Nature Limited

Keyword: Stress; Depression
Link ID: 29592 - Posted: 12.07.2024

By Annie Liontas In 2016, Marchell Taylor lay in his windowless, six-by-eight cell in the Denver County Jail. Only 36 days after being released after serving time for drug and robbery convictions, he robbed a Papa John’s and assaulted an employee. Because of his record, Mr. Taylor faced 300 years of imprisonment. He asked himself: Why am I back here? Answering his question may require looking back to 1978, when he was 9 years old and his family’s car slammed into a wall. He woke up to blood on his face. The brain injury he sustained went untreated. Shortly after that, his behavior changed, and he became, in his words, “snappy and violent.” By age 10, he was regularly turning to marijuana and alcohol. At 13, he was breaking into houses. At 14, he robbed a 7-Eleven. In 1993 he was picked up for aggravated robbery and ended up in a maximum security facility. For the next two decades, Mr. Taylor was in and out of institutions like this. That is until the Brain Injury Alliance of Colorado diagnosed him with a brain injury in 2016 while he was awaiting trial. After administering a screening, psychologists at the Men’s Mental Health Transition Unit — a pioneering mental health program in the Denver County Jail — gave Mr. Taylor access to therapies for mental health, including cognitive behavioral therapy and eye movement desensitization and reprocessing therapy, which helps process traumatic memories and experiences. These treatments taught him about his brain, and he says it has made all the difference. It is tempting to dismiss brain injury at an early age as the cause of years of criminal behavior. It’s certainly true in Mr. Taylor’s case that there were other contributing factors, including ongoing substance abuse, a lack of money and weak social and psychological support. But after spending years researching brain injuries in an effort to understand my own recovery from several and as a friend of Mr. Taylor’s, I’m reckoning with the fact that experts are only now beginning to recognize the connection between brain injury and incarceration. While such trauma may not offer a tidy explanation for histories like his, growing insight into this connection offers an opportunity to change the grim legacy of incarceration and mental illness in this country by treating an underlying factor that can fuel recidivism. © 2024 The New York Times Company

Keyword: Aggression; Brain Injury/Concussion
Link ID: 29585 - Posted: 12.04.2024

By Claudia López Lloreda For decades, researchers have considered the brain “immune privileged”—protected from the vagaries of the body’s immune system. But building evidence suggests that the brain may be more immunologically active than previously thought, well beyond its own limited immune response. The choroid plexus in particular—the network of blood vessels and cerebrospinal-fluid (CSF)-producing epithelial cells that line the organ’s ventricles—actively recruits immune cells from both the periphery and the CSF, according to a new study in mice. The epithelial layer of the choroid plexus shields the rest of the brain from toxic substances, pathogens and other molecules that circulate in the blood. Dysfunction and neuroinflammation in the choroid plexus is associated with aging and many neurological conditions, such as amyotrophic lateral sclerosis and Alzheimer’s disease. Even in the absence of inflammation, the choroid plexus harbors immune cells, some of which reside in the space between the vessels and the epithelial layer, and some on the epithelial surface. During an immune response, it also contains recruited cells, such as macrophages and other leukocytes, and pro-inflammatory signals, previous research has shown. But those findings offered only a snapshot of the cells’ locations, says Maria Lehtinen, professor of pathology at Harvard Medical School, who led the new work. “Just because [the cell] is in the tissue doesn’t mean it’s necessarily crossing or has gone in the direction that you anticipate that it would be going in.” How the choroid plexus gatekeeps immune cells remains a big question in the field, says Michal Schwartz, a neuroimmunologist at the Weizmann Institute of Science, who was not involved with the new work. © 2024 Simons Foundation

Keyword: Neuroimmunology
Link ID: 29571 - Posted: 11.23.2024

By Joanne Silberner To describe the destructive effects of intense health anxiety to his young doctors in training at Columbia University Irving Medical Center in New York City, psychiatrist Brian Fallon likes to quote 19th-century English psychiatrist Henry Maudsley: “The sorrow which has no vent in tears may make other organs weep.” That weeping from other parts of the body may come in the form of a headache that, in the mind of its sufferer, is flagging a brain tumor. It may be a rapid heartbeat a person wrongly interprets as a brewing heart attack. The fast beats may be driven by overwhelming, incapacitating anxiety. Hal Rosenbluth, a businessman in the Philadelphia area, says he used to seek medical care for the slightest symptom. In his recent book Hypochondria, he describes chest pains, breathing difficulties and vertigo that came on after he switched from a daily diabetes drug to a weekly one. He ended up going to the hospital by ambulance for blood tests, multiple electrocardiograms, a chest x-ray, a cardiac catheterization and an endoscopy, all of which were normal. Rosenbluth’s worries about glucose levels had led him to push for the new diabetes drug, and its side effects were responsible for many of his cardiac symptoms. His own extreme anxiety had induced doctors to order the extra care. Hypochondria can, in extreme cases, leave people unable to hold down a job or make it impossible for them to leave the house, cook meals, or care for themselves and their families. Recent medical research has shown that hypochondria is as much a real illness as depression and post-traumatic stress disorder. This work, scientists hope, will convince doctors who believed the disorder was some kind of character flaw that their patients are truly ill—and in danger. A study published just last year showed that people with hypochondria have higher death rates than similar but nonafflicted people, and the leading nonnatural cause of death was suicide. It was relatively rare, but the heightened risk was clear.

Keyword: Stress; Attention
Link ID: 29567 - Posted: 11.20.2024

By Miryam Naddaf Humans have evolved disproportionately large brains compared with our primate relatives — but this neurological upgrade came at a cost. Scientists exploring the trade-off have discovered unique genetic features that show how human brain cells handle the stress of keeping a big brain working. The work could inspire new lines of research to understand conditions such as Parkinson’s disease and schizophrenia. The study, which was posted to the bioRxiv preprint server on 15 November1, focuses on neurons that produce the neurotransmitter dopamine, which is crucial for movement, learning and emotional processing. By comparing thousands of laboratory-grown dopamine neurons from humans, chimpanzees, macaques and orangutans, researchers found that human dopamine neurons express more genes that boost the activity of damage-reducing antioxidants than do those of the other primates. The findings, which are yet to be peer-reviewed, are a step towards “understanding human brain evolution and all the potentially negative and positive things that come with it”, says Andre Sousa, a neuroscientist at the University of Wisconsin–Madison. “It's interesting and important to really try to understand what's specific about the human brain, with the potential of developing new therapies or even avoiding disease altogether in the future.” Just as walking upright has led to knee and back problems, and changes in jaw structure and diet resulted in dental issues, the rapid expansion of the human brain over evolutionary time has created challenges for its cells, says study co-author Alex Pollen, a neuroscientist at the University of California, San Francisco. “We hypothesized that the same process may be occurring, and these dopamine neurons may represent vulnerable joints.” © 2024 Springer Nature Limited

Keyword: Development of the Brain; Stress
Link ID: 29565 - Posted: 11.20.2024

By Sara Manning Peskin Seven Deadly Sins: The Biology of Being Human Guy Leschziner William Collins (2024) There is no food in sight in Alex’s house. Even the rubbish bin is fastened closed. The kitchen is like a bank vault, hidden behind a locked door from which staff members bring out portioned meals for Alex and her six housemates, all of whom have a genetic disorder called Prader–Willi syndrome. Although Alex was born underweight, by early adulthood she could eat three servings in a sitting, had gorged on cat food and carried 110 kilograms on her small frame. Her ‘gluttony’, writes neurologist Guy Leschziner in Seven Deadly Sins, is the result of a condition that instils such a voracious appetite that some people have eaten to the point of bursting their stomachs. Whereas marketers of diet programmes have conventionally coupled obesity to a lack of willpower, Leschziner uses Alex’s case to argue that body size is driven less by moralistic factors and more by genetics, hormones and gut microorganisms. Similar themes run throughout the book, as the author examines lust, envy and other supposed infractions, gathering examples of people who exhibit these traits because of neurological disorders. Like his earlier books about sleep and the senses, Seven Deadly Sins educates as much as it entertains, turning complex neuroscientific topics into fodder for cocktail-party conversations. The biology of behaviour Exploring wrath, Leschziner introduces two men with epilepsy. One lurches into rages in the wake of his seizures and finds himself surrounded by shards of broken dishes afterwards. Another, a “gentle giant”, has anger outbursts because of a medication prescribed to control his disease. © 2024 Springer Nature Limited

Keyword: Emotions
Link ID: 29564 - Posted: 11.20.2024

By Claudia López Lloreda Fear memories serve a purpose: A mouse in the wild learns to fear the sound of footsteps, which helps it avoid predators. But in certain situations, those fear memories can also tinge neutral memories with fear, resulting in maladaptive behavior. A mouse or person, for instance, may learn to fear stimuli that should presumably be safe. This shift can occur when an existing fear memory broadens—either by recruiting inappropriate neurons into the cell ensemble that contains it or by linking up to a previously neutral memory, according to two new studies in mice, one published today and another last week. Memories are embodied in the brain through sparse ensembles of neurons, called engrams, that activate when an animal forms a new memory or recalls it later. These ensembles were thought to be “stable and permanent,” says Denise Cai, associate professor of neuroscience at the Icahn School of Medicine at Mount Sinai, who led one of the studies. But the new findings reveal how, during times of fear and stress, memories can become malleable, either as they are brought back online or as the neurons that encode them expand. There is “this really powerful ability of stress to look back and change memories for neutral experiences that have come before by pulling them into the same neural representation or by exciting them more during offline periods,” says Elizabeth Goldfarb, assistant professor of psychiatry at the Yale School of Medicine, who was not involved in the studies. That challenges the previous dogma, Cai says. “We’ve learned that these memory ensembles are actually quite dynamic.” © 2024 Simons Foundation

Keyword: Learning & Memory; Stress
Link ID: 29563 - Posted: 11.16.2024

By Angie Voyles Askham Engrams, the physical circuits of individual memories, consist of more than just neurons, according to a new study published today in Nature. Astrocytes, too, shape how some memories are stored and retrieved, the work shows. The results represent “a fundamental change” in how the neuroscience field should think about indexing memories, says lead researcher Benjamin Deneen, professor of neurosurgery at Baylor College of Medicine. “We need to reconsider the cellular, physical basis of how we store memories.” When mice form a new memory, a specific set of neurons becomes active and expresses the immediate early gene c-FOS, past work has found. Reactivating that ensemble of neurons, the engram, causes the mice to recall that memory. Interactions between neurons and astrocytes are critical for the formation of long-term memory, according to a spatial transcriptomics study from February, and both astrocytes and oligodendrocytes are involved in memory formation, other work has shown. Yet engram studies have largely ignored the activity of non-neuronal cells, says Sheena Josselyn, senior scientist at the Hospital for Sick Children, who was not involved in the new study. But astrocytes are also active alongside neurons as memories are formed and recalled, and disrupting the star-shaped cells’ function interferes with these processes, the new work reveals. The study does not dethrone neurons as the lead engram stars, according to Josselyn. “It really shows that, yes, neurons are important. But there are also other players that we’re just beginning to understand the importance of,” she says. “It’ll help broaden our focus.” © 2024 Simons Foundation

Keyword: Learning & Memory; Glia
Link ID: 29558 - Posted: 11.13.2024

By Angie Voyles Askham Keeping track of social hierarchies is crucial for any animal. Primates in particular must adapt their behaviors based on the status of those around them, or risk losing their own rank. “True, smart social behavior in humans and in monkeys is dependent on a full adjustment to the context,” says Katalin Gothard, professor of physiology and neuroscience at the University of Arizona. Multiple brain areas keep track of social information. Among them, the amygdala—known for processing emotions—responds to faces, facial expressions and social status, and activates as people learn social hierarchies. But the brain adapts this information for different social settings, a new study reveals: Neurons in the macaque amygdala encode knowledge about social status in a context-specific way, Gothard and her colleagues discovered. Just like people, macaques can infer social standing from videos, and the activity of amygdala cells captures information about both the identity of the individual they are watching and how that animal relates to others in the scene. These findings help explain how primates process information about social position, says Ralph Adolphs, professor of psychology and neuroscience at California Institute of Technology, who was not involved in the work. And because the monkeys could successfully learn this information from videos, the results open up a new avenue for studying how the primate brain encodes these relationships in a complex and dynamic way, he adds. “That’s a big step forward.” Like people, macaques have no physical traits that directly convey dominance, Gothard says. “The status of these individuals is inferred.” So she and her colleagues tested two macaques’ ability to understand a hierarchy that the team invented among four unfamiliar monkeys in a series of videos. Each clip simulated status-appropriate interactions between two of the four monkeys on a split screen to convey those two animals’ relative positions: a scene of a higher-ranked animal acting aggressive juxtaposed with one of a lower-ranked monkey smacking its lips in appeasement, for example. © 2024 Simons Foundation

Keyword: Emotions; Attention
Link ID: 29544 - Posted: 11.06.2024

By Claire Murashima What do you think of when you hear the term “OCD”? In pop culture, people with obsessive-compulsive disorder are often portrayed as meticulous to an extreme degree. They’re highly organized, perfectionistic, or germophobic — like Jack Nicholson’s character in the film As Good As It Gets, who tosses out bars of soap after using them once. Depictions like that aren’t inaccurate, but they’re not the whole story. Research shows that 1 in 40 American adults have OCD or will develop it at some point in their lives, according to the International OCD Foundation. Although the term “OCD” is often used casually, the disorder must be diagnosed by a medical professional. We wanted to take a closer look at how people with OCD cope with it every day as OCD Awareness Month wraps up. I live with OCD, and it impacts just about every aspect of my life. Growing up, I had to say a prayer before I ate anything, because I thought I’d vomit if I didn’t. Later in life, I struggled with flying, because I feared that I might vomit on the plane, or that someone might vomit near me. The fear of vomiting is called emetophobia, and it’s a common symptom of OCD — though it’s not talked about as often. People with OCD can experience very specific intrusive thoughts known as obsessions, and then engage in compulsions, which are ritualized behaviors to address them, according to the International OCD Foundation. Anxiety can be the underlying emotion of OCD — but unlike generalized anxiety disorder, the underlying emotion could also be a sense of disgust, wrongness or incompleteness, according to Dr. Christopher Pittenger, the director of the Yale School of Medicine OCD Research Clinic. © 2024 npr

Keyword: OCD - Obsessive Compulsive Disorder
Link ID: 29536 - Posted: 11.02.2024

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

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

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

Keyword: Stress
Link ID: 29517 - Posted: 10.16.2024

By Jennifer Couzin-Frankel Even a mild concussion can cause disconcerting and sometimes lasting symptoms, such as trouble concentrating and dizziness. But can it make someone more likely to commit a crime? After all, a disproportionate number of people in the criminal justice system previously suffered a traumatic brain injury (TBI). But according to new research into the medical and juvenile justice records of Danish teenagers who suffered a blow to head as children, such injuries don’t cause criminal behavior. Although TBI and criminality often travel together, the researchers found in this Danish population it’s a case of correlation, not causation. “I think this study very clearly indicates that you can’t just [say], ‘Hey, my kid has a mild TBI, he or she is screwed,” says Joseph Schwartz, a criminologist at Florida State University who has studied the issue in juveniles and adults. At the same time, he cautions that there are important variables this study wasn’t designed to capture, such as the treatment received, the effect of repeat TBIs, and the circumstances surrounding the injury. All of these, he says, could influence criminal behavior in some people. Beyond showing high rates of past TBI among those charged with or convicted of crimes, research into this topic has been limited. Studies have found that mild TBI is associated with later behavioral problems, including impulsivity and inattentiveness, which are also linked with criminal behavior. At the same time, it’s well known that “the risk factors in the child and the family for TBIs are the same as the risk factors for delinquency,” including poverty and parental substance abuse, says Sheilagh Hodgins, a clinical psychologist at the University of Montreal. She notes, too, that impulsivity and attention and conduct disorders heighten the risk of sustaining a mild TBI in the first place. © 2024 American Association for the Advancement of Science.

Keyword: Brain Injury/Concussion; Aggression
Link ID: 29503 - Posted: 10.02.2024

Ian Sample Science editor Where does our personal politics come from? Does it trace back to our childhood, the views that surround us, the circumstances we are raised in? Is it all about nurture – or does nature have a say through the subtle levers of DNA? And where, in all of this, is the brain? Scientists have delved seriously into the roots of political belief for the past 50 years, prompted by the rise of sociobiology, the study of the biological basis of behaviour, and enabled by modern tools such as brain scanners and genome sequencers. The field is making headway, but teasing out the biology of behaviour is never straightforward. Take a study published last week. Researchers in Greece and the Netherlands examined MRI scans from nearly 1,000 Dutch people who had answered questionnaires on their personal politics. The work was a replication study, designed to see whether the results from a small 2011 study, bizarrely commissioned by the actor Colin Firth, stood up. Firth’s study, conducted at UCL, reported structural differences between conservative and liberal brains. Conservatives, on average, had a larger amygdala, a region linked to threat perception. Liberals, on average, had a larger anterior cingulate cortex, a region involved in decision-making. In the latest study of Dutch people, the researchers found no sign of a larger anterior cingulate cortex in liberals. They did, however, find evidence for a very slightly larger amygdala in conservatives. The MailOnline declared evidence that conservatives were more “compassionate”, but later changed their headline noting that the study said nothing about compassion. © 2024 Guardian News & Media Limited

Keyword: Emotions; Attention
Link ID: 29493 - Posted: 09.25.2024

By Gina Kolata and Stephanie Nolen The Lasker Awards, a prestigious set of prizes given for advances in medicine and public health research, were given on Thursday to scientists whose research helped lead to the discovery of a new class of obesity drugs, infectious disease specialists who worked on the drivers of H.I.V. infection and how to stop it, and a scientist who discovered a way the body protects itself from infectious diseases and cancer. The Laskers are highly regarded in the fields of biomedicine and are sometimes seen as foretelling recipients of the Nobel Prizes in the sciences. This year’s Lasker-DeBakey Clinical Medical Research Award went to three scientists for their work on GLP-1, the hormone that led to drugs like Wegovy (the same compound is the basis for Ozempic), which have transformed the treatment of obesity. They are Dr. Joel Habener, Svetlana Mojsov and Lotte Bjerre Knudsen. Each of the three honorees played a role at a key moment: finding the new hormone; finding the biologically active shorter form of GLP-1; and, finally, showing that the shorter form elicits weight loss. Of course, as almost always happens in science, many others also played key roles, and the Lasker Foundation mentioned some as part of its citation. And one of the honorees, Dr. Mojsov, is receiving what many deem a long overdue recognition. The story of GLP-1 begins with Dr. Habener, an endocrinologist who arrived in the mid-1970s at Massachusetts General Hospital, where he decided to work on diabetes. Most of the focus had been on insulin, which lowers blood sugar levels. But there is another hormone, glucagon, that raises it. Dr. Habener decided to try to find the gene for glucagon, hoping it would lead to a way to squelch the hormone and so lower blood sugar. Working with anglerfish, he discovered a gene for another mysterious protein that resembles glucagon. © 2024 The New York Times Company

Keyword: Obesity; Neuroimmunology
Link ID: 29488 - Posted: 09.21.2024

Does a whiff of pollen trigger a sneeze or a cough? Scientists have discovered nerve cells that cause one response versus another: ‘sneeze neurons’ in the nasal passages relay sneeze signals to the brain, and separate neurons send cough messages, according to a study1 performed in mice. The findings could lead to new and improved treatments for conditions such as allergies and chronic coughs. That’s welcome news because these conditions can be “incredibly frustrating” and the side effects of current treatments can be “incredibly problematic”, says pulmonologist Matthew Drake at Oregon Health & Science University in Portland, who was not involved in the work. The study was published today in Cell. Previous work2 categorized neurons in the mouse airway on the basis of the proteins complexes, called ion channels, that are carried on the cell surfaces. To work out which nose neurons cause sneezing, researchers exposed mice to various compounds, each known to activate specific types of ion channel. They struck gold when a substance called BAM 8-22 left the mice sneezing. The compound is known to activate an ion channel called MrgprC11, leading the researchers to suspect that neurons carrying MrgprC11 cause sneezing. Indeed, when the researchers deleted MrgprC11 from the suspected sneeze neurons and then gave mice the flu, they found themselves with sick, but sneezeless, mice. Even with the sneeze neurons out of the picture, the sick mice continued to have cough-like reactions to influenza infection. Using methods similar to those that homed in on the sneeze neurons, the researchers tracked the cough response to a set of neurons in the trachea that express a signalling chemical called somatostatin. Viruses “evolve very quickly”, says neuroscientist and study co-author Qin Liu at Washington University in St. Louis, Missouri. That could explain why there are two separate systems capable of detecting and clearing them from the airways. © 2024 Springer Nature Limited

Keyword: Neuroimmunology
Link ID: 29466 - Posted: 09.07.2024

By Julian Nowogrodzki A newly devised ‘brain clock’ can determine whether a person’s brain is ageing faster than their chronological age would suggest1. Brains age faster in women, countries with more inequality and Latin American countries, the clock indicates. “The way your brain ages, it’s not just about years. It’s about where you live, what you do, your socio-economic level, the level of pollution you have in your environment,” says Agustín Ibáñez, the study’s lead author and a neuroscientist at Adolfo Ibáñez University in Santiago. “Any country that wants to invest in the brain health of the people, they need to address structural inequalities.” The work is “truly impressive”, says neuroscientist Vladimir Hachinski at Western University in London, Canada, who was not involved in the study. It was published on 26 August in Nature Medicine. Only connect The researchers looked at brain ageing by assessing a complex form of functional connectivity, a measure of the extent to which brain regions are interacting with one another. Functional connectivity generally declines with age. The authors drew on data from 15 countries: 7 (Mexico, Cuba, Colombia, Peru, Brazil, Chile and Argentina) that are in Latin America or the Caribbean and 8 (China, Japan, the United States, Italy, Greece, Turkey, the United Kingdom and Ireland) that are not. Of the 5,306 participants, some were healthy, some had Alzheimer’s disease or another form of dementia and some had mild cognitive impairment, a precursor to dementia. The researchers measured participants’ resting brain activity — that when they were doing nothing in particular — using either functional magnetic resonance imaging (fMRI) or electroencephalography (EEG). The first technique measures blood flow in the brain, and the second measures brain-wave activity. © 2024 Springer Nature Limited

Keyword: Development of the Brain; Stress
Link ID: 29458 - Posted: 08.31.2024

By R. Douglas Fields It is late at night. You are alone and wandering empty streets in search of your parked car when you hear footsteps creeping up from behind. Your heart pounds, your blood pressure skyrockets. Goose bumps appear on your arms, sweat on your palms. Your stomach knots and your muscles coil, ready to sprint or fight. Now imagine the same scene, but without any of the body’s innate responses to an external threat. Would you still feel afraid? Experiences like this reveal the tight integration between brain and body in the creation of mind — the collage of thoughts, perceptions, feelings and personality unique to each of us. The capabilities of the brain alone are astonishing. The supreme organ gives most people a vivid sensory perception of the world. It can preserve memories, enable us to learn and speak, generate emotions and consciousness. But those who might attempt to preserve their mind by uploading its data into a computer miss a critical point: The body is essential to the mind. How is this crucial brain-body connection orchestrated? The answer involves the very unusual vagus nerve. The longest nerve in the body, it wends its way from the brain throughout the head and trunk, issuing commands to our organs and receiving sensations from them. Much of the bewildering range of functions it regulates, such as mood, learning, sexual arousal and fear, are automatic and operate without conscious control. These complex responses engage a constellation of cerebral circuits that link brain and body. The vagus nerve is, in one way of thinking, the conduit of the mind. Nerves are typically named for the specific functions they perform. Optic nerves carry signals from the eyes to the brain for vision. Auditory nerves conduct acoustic information for hearing. The best that early anatomists could do with this nerve, however, was to call it the “vagus,” from the Latin for “wandering.” The wandering nerve was apparent to the first anatomists, notably Galen, the Greek polymath who lived until around the year 216. But centuries of study were required to grasp its complex anatomy and function. This effort is ongoing: Research on the vagus nerve is at the forefront of neuroscience today. © 2024.Simons Foundation

Keyword: Emotions; Obesity
Link ID: 29454 - Posted: 08.28.2024

By Elyse Weingarten In 2016, Canada enacted the Medical Assistance in Dying, or MAID, law, allowing individuals with a terminal illness to receive help from a medical professional to end their life. Following a superior court ruling, the legislation was expanded in 2021 to include nearly anyone with a “grievous and irremediable medical condition” causing “enduring physical or psychological suffering that is intolerable to them.” Whether mental illnesses such as depression, schizophrenia, and addiction should be considered “grievous and irremediable” quickly emerged as the subject of intense debate. Initially slated to go into effect in March 2023, a new mental health provision of the law was postponed a year due to public outcry both in Canada and abroad. Then, in February, Health Minister Mark Holland announced it had been delayed again — this time until 2027 — to allow more time for the country’s health care system to prepare. I was horrified by the news of the law’s latest expansion — a reaction that surprised me. Having grown up with a seriously mentally ill family member, I know first-hand how destructive mental illness can be, and I have no illusion that it is always treatable. Additionally, I support assisted suicide in cases of grave and terminal physical illness, so why do I find it so unacceptable to offer it to people who are intractably mentally ill? For nearly half a century, the Western understanding of mental illness has been shaped to adhere to the larger biomedical concepts of disease and wellness. Biological psychiatry, or the biomedical model, views mental illnesses as organically based disorders of the brain, physiologically indistinguishable from other diseases. The Canadian MAID law’s inclusion of mental illness is the culmination of this framework. Yet the widespread condemnation that the amendment received (that the bill’s previous iterations did not) demonstrates that mental and physical illness — though worthy of the same respect — are in no way equivalent, and that we can recognize this intuitively.

Keyword: Depression; Schizophrenia
Link ID: 29449 - Posted: 08.22.2024

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