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

Joe Hernandez If a human or another animal close to them dies, does a cat grieve the loss? That was the question a team of researchers from Oakland University in Michigan set out to answer when they surveyed hundreds of cat owners about their cat’s behavior after another cat or dog in the household passed away. The data showed that cats exhibited behaviors associated with grief — such as eating and playing less — more often after the death of a fellow pet, suggesting they may in fact have been in mourning. “It made me a little more optimistic that they are forming attachments with each other,” said Jennifer Vonk, a professor of psychology at Oakland University, who co-authored the study, published in the journal Applied Animal Behaviour Science. “It’s not that I want the cats to be sad,” Vonk went on, “[but] there is a part of us, I think, as humans that wants to think that if something happens to us our pets would miss us.” Though animals from elephants to horses to dogs have been shown to express signs of grief, less is known about the emotional life of the domesticated house cat. Vonk said she knew of only one other study on grief in domestic cats. For their research, Vonk and her coauthor, Brittany Greene, surveyed 412 cat caregivers about how their feline companion acted after another pet in the house died. They found that, after the death of a fellow pet, cats on average sought more attention from their owners, spent more time alone, appeared to look for the deceased animal, ate less and slept more. © 2024 npr

Keyword: Emotions; Evolution
Link ID: 29426 - Posted: 08.11.2024

By Michael S. Rosenwald Dr. J. Robin Warren, an Australian pathologist who shared a Nobel Prize for discovering that most stomach ulcers were caused by the bacterium Helicobacter pylori — and not, as had been widely believed, stress, alcohol or spicy foods — died on July 23 in Inglewood, Australia. He was 87. His death, at a care home, was announced by the University of Western Australia in Perth, where he was an emeritus professor for many years. His daughter-in-law Gigi Warren said the cause was complications after a recent fall. In 1984, Dr. Warren and his collaborator, the gastroenterologist Barry Marshall, published a paper in the British medical journal The Lancet describing their finding that the spiral-shaped bacterium now commonly called H. pylori festered in the stomachs of patients with ulcers and gastritis. Dr. Warren had first noticed the bacterium on a gastric biopsy sample in 1979. The paper’s conclusion upended centuries of conventional wisdom about the cause of ulcers. (Psychoanalysts had even written of the “peptic ulcer personality.”) Doctors typically prescribed stress reduction, a bland diet and, starting in 1977, drugs like Tagamet and Zantac to tame the burning acids. Severe cases were sometimes treated with surgery. When the study was published, gastroenterologists were skeptical. They expressed concern about whether to trust potentially paradigm-shifting findings made by two unknown researchers in Australia. And the idea that bacteria could even grow in the stomach was considered blasphemy. “For about 100 years, or 1,000 years, the standard teaching in medicine was that the stomach was sterile and nothing grew there because of corrosive gastric juices,” Dr. Warren told The New York Times in 2005 after he and Dr. Marshall won the Nobel Prize in Physiology or Medicine. “So everybody believed there were no bacteria in the stomach. When I said they were there, no one believed it.” © 2024 The New York Times Company

Keyword: Stress
Link ID: 29425 - Posted: 08.11.2024

By Ellen Barry In recent decades, mental health providers began screening for “adverse childhood experiences” — generally defined as abuse, neglect, violence, family dissolution and poverty — as risk factors for later disorders. But what if other things are just as damaging? Researchers who conducted a large study of adults in Denmark, published on Wednesday in the journal JAMA Psychiatry, found something they had not expected: Adults who moved frequently in childhood have significantly more risk of suffering from depression than their counterparts who stayed put in a community. In fact, the risk of moving frequently in childhood was significantly greater than the risk of living in a poor neighborhood, said Clive Sabel, a professor at the University of Plymouth and the paper’s lead author. “Even if you came from the most income-deprived communities, not moving — being a ‘stayer’ — was protective for your health,” said Dr. Sabel, a geographer who studies the effect of environment on disease. “I’ll flip it around by saying, even if you come from a rich neighborhood, but you moved more than once, that your chances of depression were higher than if you hadn’t moved and come from the poorest quantile neighborhoods,” he added. The study, a collaboration by Aarhus University, the University of Manchester and the University of Plymouth, included all Danes born between 1982 and 2003, more than a million people. Of those, 35,098, or around 2.3 percent, received diagnoses of depression from a psychiatric hospital. Are you concerned for your teen? If you worry that your teen might be experiencing depression or suicidal thoughts, there are a few things you can do to help. Dr. Christine Moutier, the chief medical officer of the American Foundation for Suicide © 2024 The New York Times Company

Keyword: Depression; Stress
Link ID: 29395 - Posted: 07.18.2024

By Freda Kreier Dogs’ ability to feel your pain could be innate. It is the result of centuries of co-evolution with humans, suggests a community-science study that compared the responses of dogs and pet pigs to the sound of humans crying and humming. The results were published on 2 July in Animal Behaviour1. Humans pay attention to how the animals in their lives are feeling, and it seems that this attentiveness is reciprocal. Researchers have found that horses will stop and listen longer to human growls than to laughter2. Pigs respond more strongly to sounds made by people than wild boars do3. But studies testing whether the animals are just reacting to weird human sounds, or are capable of true emotional contagion — the ability to interpret and reflect people’s emotional states — are thin on the ground. Most animals can accurately echo the feelings of only other members of their species. But studies have shown that dogs (Canis familiaris) can mirror the emotions of the people around them4,5. One question is whether this emotional contagion is rooted in ‘universal vocal signals of emotion ’ that can be understood by all domesticated animals, or is specific to companion animals such as dogs. To test this, researchers compared the stress response of dogs and pet pigs (Sus scrofa domesticus) to human sounds. Pet sounds Like dogs, pet pigs are social animals that are from a young age raised around people. But unlike dogs, pigs have been kept as livestock for most of their history with humans. So, if emotional contagion can be learnt through just proximity to people, pet pigs should respond in similar ways to dogs. The team recruited dog or pig owners around the world to film themselves in a room with their pets while playing recorded sounds of crying or humming. Researchers then tallied the number of stress behaviours — such as whining and yawning for dogs, and rapid ear flicks for pigs — exhibited during the experiment. © 2024 Springer Nature Limited

Keyword: Emotions; Evolution
Link ID: 29394 - Posted: 07.18.2024

By Erin Garcia de Jesús In spring 2022, a handful of red foxes in Wisconsin were behaving oddly. Veterinary pathologist Betsy Elsmo learned that a local wildlife rehabilitation center was caring for foxes with neurological symptoms like seizures, tremors, uncoordinated movements and lethargy. But tests for common pathogens like canine distemper virus and rabies that typically cause the symptoms came back negative. Then a red fox kit tested positive for influenza A. This group of viruses includes seasonal flus that cause respiratory disease in people and many other strains that commonly circulate among animals such as waterfowl and other birds. “I was surprised,” says Elsmo, of the University of Wisconsin–Madison. “And to be honest, at first I kind of wrote it off.” That is, until a veterinary technician at the rehab center sent Elsmo a study describing cases of avian influenza in red foxes in the Netherlands. Examinations of the Wisconsin kit’s tissues under the microscope revealed lesions in the brain, lung and heart that matched what had been seen in the Netherlands animals. “And I thought, I think it is [bird flu],” she recalls. Additional testing confirmed the diagnosis in the kit and the other foxes, Elsmo and colleagues reported in the December 2023 Emerging Infectious Diseases. The animals had contracted a lethal strain of H5N1 avian influenza that emerged in late 2020 in Europe and has since spread around the world. At the time infections were discovered in the Wisconsin red foxes, bird flu was expanding its incursion into North America. Since H5N1 arrived on North American shores in December 2021, it has infected animals as wide-ranging as polar bears, skunks, sea lions, bottlenosed dolphins and cows (SN: 7/8/24). And one unwelcome revelation of the ongoing outbreak is the virus’s propensity to invade the brains of myriad mammals. © Society for Science & the Public 2000–2024.

Keyword: Stress
Link ID: 29392 - Posted: 07.13.2024

By Dana G. Smith In July 2016, a heat wave hit Boston, with daytime temperatures averaging 92 degrees for five days in a row. Some local university students who were staying in town for the summer got lucky and were living in dorms with central air-conditioning. Other students, not so much — they were stuck in older dorms without A.C. Jose Guillermo Cedeño Laurent, a Harvard researcher at the time, decided to take advantage of this natural experiment to see how heat, and especially heat at night, affected the young adults’ cognitive performance. He had 44 students perform math and self-control tests five days before the temperature rose, every day during the heat wave, and two days after. “Many of us think that we are immune to heat,” said Dr. Cedeño, now an assistant professor of environmental and occupational health and justice at Rutgers University. “So something that I wanted to test was whether that was really true.” It turns out even young, healthy college students are affected by high temperatures. During the hottest days, the students in the un-air-conditioned dorms, where nighttime temperatures averaged 79 degrees, performed significantly worse on the tests they took every morning than the students with A.C., whose rooms stayed a pleasant 71 degrees. A heat wave is once again blanketing the Northeast, South and Midwest. High temperatures can have an alarming effect on our bodies, raising the risk for heart attacks, heatstroke and death, particularly among older adults and people with chronic diseases. But heat also takes a toll on our brains, impairing cognition and making us irritable, impulsive and aggressive. Numerous studies in lab settings have produced similar results to Dr. Cedeño’s research, with scores on cognitive tests falling as scientists raised the temperature in the room. One investigation found that just a four-degree increase — which participants described as still feeling comfortable — led to a 10 percent average drop in performance across tests of memory, reaction time and executive functioning. © 2024 The New York Times Company

Keyword: Aggression
Link ID: 29370 - Posted: 06.26.2024

By Esther Landhuis Last month, researchers discovered cells in the brainstem that regulate inflammation throughout the body. In response to an injury, these nerve cells not only sense inflammatory molecules, but also dial their circulating levels up and down to keep infections from harming healthy tissues. The discovery adds control of the immune system to the brainstem’s core functions — a list that also includes monitoring heart rate, breathing and aspects of taste — and suggests new potential targets for treating inflammatory disorders like arthritis and inflammatory bowel disease. During an intense workout or high-stakes exam, your brain can sense the spike in your heart rate and help restore a normal rhythm. Likewise, the brain can help stabilize your blood pressure by triggering chemical signals that widen or constrict blood vessels. Such feats often go unnoticed, but they illustrate a fundamental concept of physiology known as homeostasis — the capacity of organisms to keep their internal systems working smoothly and stably amid shifting circumstances. Now, in a paper published on May 1 in Nature, researchers describe how homeostatic control extends even to the sprawl of cells and tissues that comprise our immune system. The team applied a clever genetic approach in mice to identify cells in the brainstem that adjust immune reactions to pathogens and other outside triggers. These neurons operate like a “volume controller” that keeps the animals’ inflammatory responses within a physiological range, said paper author Hao Jin, a neuroimmunologist at the National Institute of Allergy and Infectious Diseases. © 2024 Simons Foundation.

Keyword: Miscellaneous
Link ID: 29361 - Posted: 06.15.2024

By Ellen Barry Post-traumatic stress disorder diagnoses among college students more than doubled between 2017 and 2022, climbing most sharply as the coronavirus pandemic shut down campuses and upended young adults’ lives, according to new research published on Thursday. The prevalence of PTSD rose to 7.5 percent from 3.4 percent during that period, according to the findings. Researchers analyzed responses from more than 390,000 participants in the Healthy Minds Study, an annual web-based survey. “The magnitude of this rise is indeed shocking,” said Yusen Zhai, the paper’s lead author, who heads the community counseling clinic at the University of Alabama at Birmingham. His clinic had seen more young people struggling in the aftermath of traumatic events. So he expected an increase, but not such a large one. Dr. Zhai, an assistant professor in the Department of Human Studies, attributed the rise to “broader societal stressors” on college students, such as campus shootings, social unrest and the sudden loss of loved ones from the coronavirus. PTSD is a mental health disorder characterized by intrusive thoughts, flashbacks and heightened sensitivity to reminders of an event, continuing more than a month after it occurs. It is a relatively common disorder, with an estimated 5 percent of adults in the United States experiencing it in any given year, according to the most recent epidemiological survey conducted by the Department of Health and Human Services. Lifetime prevalence is 8 percent in women and 4 percent in men, the survey found. The new research also found a sharp rise in the prevalence of a similar condition, acute stress disorder, which is diagnosed less than a month after a trauma. Diagnoses rose to 0.7 percent among college students in 2022, up from 0.2 percent five years earlier. Use of mental health care increased nationally during the pandemic, as teletherapy made it far easier to see clinicians. Treatment for anxiety disorders increased most steeply, followed by PTSD, bipolar disorder and depression, according to economists who analyzed more than 1.5 million insurance claims for clinician visits between 2020 and 2022. © 2024 The New York Times Company

Keyword: Stress
Link ID: 29350 - Posted: 06.08.2024

By Andrew Jacobs An independent advisory panel of the Food and Drug Administration rejected the use of MDMA-assisted therapy for post-traumatic stress disorder on Tuesday, highlighting the unparalleled regulatory challenges of a novel therapy using the drug commonly known as Ecstasy. Before the vote, members of the panel raised concerns about the designs of the two studies submitted by the drug’s sponsor, Lykos Therapeutics. Many questions focused on the fact that study participants were by and large able to correctly guess whether they had been given MDMA, also known by the names of Ecstasy or molly. The panel voted 9-2 on whether the MDMA-assisted therapy was effective, and voted 10-1 on whether the proposed treatment’s benefits outweighed its risks. Other panelists expressed concerns over the drug’s potential cardiovascular effects, and possible bias among the therapists and facilitators who guided the sessions and may have positively influenced patient outcomes. A case of misconduct involving a patient and therapist in the study also weighed on some panelists’ minds. Many of the committee members said they were especially worried about the failure of Lykos to collect detailed data from participants on the potential for abuse of a drug that generates feelings of bliss and well-being. “I absolutely agree that we need new and better treatments for PTSD,” said Paul Holtzheimer, deputy director for research at the National Center for PTSD, a panelist who voted no on the question of whether the benefits of MDMA-therapy outweighed the risks. “However, I also note that premature introduction of a treatment can actually stifle development, stifle implementation and lead to premature adoption of treatments that are either not completely known to be safe, not fully effective or not being used at their optimal efficacy,” he added. © 2024 The New York Times Company

Keyword: Stress; Drug Abuse
Link ID: 29343 - Posted: 06.06.2024

By Ellen Barry The annual gathering of the American Psychiatric Association is a dignified and collegial affair, full of scholarly exchanges, polite laughter and polite applause. So it was a shock, for those who took their seats in Room 1E08 of the Jacob K. Javits Convention Center in Manhattan, to watch a powerfully built 32-year-old man choke back tears as he described being slammed to the floor and cuffed to a stretcher in a psychiatric unit. Because the man, Matthew Tuleja, had been a Division I football player, he had a certain way of describing the circle of bodies that closed around him, the grabbing and grappling and the sensation of being dominated, pinned and helpless. He was on the ground in a small room filled with pepper spray. Then his wrists and ankles were cuffed to the sides of a stretcher, and his pants were yanked down. They gave him injections of Haldol, an antipsychotic medication he had repeatedly tried to refuse, as he howled in protest. Forcible restraints are routine events in American hospitals. One recent study, using 2017 data from the Centers for Medicare and Medicaid Services, estimated the number of restraints per year at more than 44,000. But it is rare to hear a first-person account of the experience, because it tends to happen to people who do not have a platform. Researchers who surveyed patients about restraint and seclusion have found that a large portion, 25 to 47 percent , met criteria for post-traumatic stress disorder. Listening, rapt, to Mr. Tuleja was a roomful of psychiatrists. It was a younger crowd — people who had entered the field at the time of the Black Lives Matter protests. Many of them lined up to speak to him afterward. “I still can’t forget the first time I saw someone restrained,” one doctor told him. “You don’t forget that.” © 2024 The New York Times Company

Keyword: Schizophrenia; Aggression
Link ID: 29317 - Posted: 05.21.2024

By Laura Sanders Everyone knows that the brain influences the heart. Stressful thoughts can set the heart pounding, sometimes with such deep force that we worry people can hear it. Anxiety can trigger the irregular skittering of atrial fibrillation. In more extreme and rarer cases, emotional turmoil from a shock — the death of a loved one, a cancer diagnosis, an intense argument — can trigger a syndrome that mimics a heart attack. But not everyone knows that the heart talks back. Subscribe to Science News Powerful signals travel from the heart to the brain, affecting our perceptions, decisions and mental health. And the heart is not alone in talking back. Other organs also send mysterious signals to the brain in ways that scientists are just beginning to tease apart. A bodywide perspective that seeks to understand our biology and behavior is relatively new, leaving lots of big, basic questions. The complexities of brain-body interactions are “only matched by our ignorance of their organization,” says Peter Strick, a neuroscientist at the University of Pittsburgh. Exploring the relationships between the heart, other organs and the brain isn’t just fascinating anatomy. A deeper understanding of how we sense and use signals from inside our bodies — a growing field called interoception — may point to new treatments for disorders such as anxiety. “We have forgotten that interactions with the internal world are probably as important as interactions with the external world,” says cognitive neuroscientist Catherine Tallon-Baudry of École Normale Supérieure in Paris. © Society for Science & the Public 2000–2024.

Keyword: Emotions; Depression
Link ID: 29313 - Posted: 05.18.2024

By Giorgia Guglielmi A population of neurons in the brain stem, the stalk-like structure that connects the bulk of the brain to the spinal cord, acts as the master dial for the immune system.Credit: Voisin/Phanie/Science Photo Library Scientists have long known that the brain plays a part in the immune system — but how it does so has been a mystery. Now, scientists have identified cells in the brainstem that sense immune cues from the periphery of the body and act as master regulators of the body’s inflammatory response. The results, published on 1 May in Nature1, suggest that the brain maintains a delicate balance between the molecular signals that promote inflammation and those that dampen it — a finding that could lead to treatments for autoimmune diseases and other conditions caused by an excessive immune response. The discovery is akin to a black-swan event — unexpected but making perfect sense once revealed, says Ruslan Medzhitov, an immunologist at Yale University in New Haven, Connecticut. Scientists have known that the brainstem has many functions, such as controlling basic processes such as breathing. However, he adds, the study “shows that there is whole layer of biology that we haven’t even anticipated”. The brain is watching After sensing an intruder, the immune system unleashes a flood of immune cells and compounds that promote inflammation. This inflammatory response must be controlled with exquisite precision: if it’s too weak, the body is at greater risk of becoming infected; if it’s too strong, it can damage the body’s own tissues and organs. Previous work has shown that the vagus nerve, a large network of nerve fibres that links the body with the brain, influences immune responses. However, the specific brain neurons that are activated by immune stimuli remained elusive, says Hao Jin, a neuroimmunologist at the US National Institute of Allergy and Infectious Diseases in Bethesda, Maryland, who led the work. © 2024 Springer Nature Limited

Keyword: Neuroimmunology
Link ID: 29286 - Posted: 05.02.2024

By J. David Creswell Let’s start thinking differently about exercise. Decades of exercise science research show that when people or animals are given a new exercise routine, they get healthier. But when thinking about the benefits of exercise, most people hold a strong body bias; they focus on how regular exercise builds more lean body mass, helps increase their strength and balance, or improves heart health. Exercise matters even more for our brains, it turns out, in ways that are often overlooked. Here’s how we know. Animal exercise studies typically run rats for weeks on running wheels. The animals gleefully run every night, sprinting several miles over the course of an evening. There are wonderful health benefits in these studies of voluntary running—improved muscle tone and cardiovascular health, and many brain benefits too. But in some studies, there’s an additional experimental condition where some rats exercise with one crucial difference: it’s no longer voluntary exercise. Instead of a freestanding running wheel, rats run on a mechanized wheel that spins, forcing the animals to cover the same distance as the voluntary runners. What happens? When the rats are forced to exercise on a daily basis for several weeks, their bodies become more physically fit, but their brains suffer. Animals regularly forced to exercise have the equivalent of an anxiety disorder, behaving on new tasks in highly anxious and avoidant ways. These animals are more anxious not only compared to the voluntary runners, but also to animals that are not given an opportunity to exercise at all. Yes, forced exercise might be worse than no exercise at all. This work suggests something important about the health benefits of exercise: it is not just about making our muscles work, but what exercise does to our brains. When exercise gives us a sense of control, mastery and joy, our brains become less anxious. If we take that away, by forcing exercise, we can shift it from helpful to harmful. © 2024 SCIENTIFIC AMERICAN,

Keyword: Stress; Depression
Link ID: 29284 - Posted: 05.02.2024

By Sabrina Malhi The phrase “anger kills” might have a more literal meaning: New research suggests a possible reason frequent anger has been linked to an increased risk of cardiovascular disease. The study, published Wednesday in the Journal of the American Heart Association, emphasizes the potential health risks associated with intense anger and illuminates the influence of negative emotions on our overall well-being. Funded by the National Institutes of Health, the study involved 280 healthy adults who were randomly assigned to a different eight-minute task, each designed to elicit feelings of anger, anxiety, sadness or neutrality. Before and after these emotional tasks, researchers assessed the participants’ endothelial health. Endothelial cells, which line the insides of blood vessels, are essential for maintaining vessel integrity and are vital for proper circulation and cardiovascular health. The findings revealed that anger had a significant negative impact on endothelial function, limiting the blood vessels’ ability to dilate. The response was not as pronounced with anxiety or sadness. According to Daichi Shimbo, a cardiologist and professor of medicine at Columbia University Irving Medical Center and the lead study author, this research marks a step toward understanding how different negative emotions particularly affect physical health. “It's fascinating that anxiety and sadness did not have the same effect as anger, suggesting that the ways in which negative emotions contribute to heart disease differ,” Shimbo said.

Keyword: Emotions; Stress
Link ID: 29282 - Posted: 05.02.2024

By Shaena Montanari The sympathetic nervous system may have originated in jawless fish—not tens of millions of years later as previously thought, according to a study published today in Nature. Anatomical work dating back to the 19th century suggested that the sympathetic nervous system was present only in jawed vertebrates. Yet the sea lamprey, the new findings reveal, sports clusters of sympathetic neurons along its trunk and expresses several genes involved in the “fight-or-flight” system, the response that kicks into gear when an animal perceives a threat. “Whenever new research causes troves of textbooks to need corrections, that’s always surprising,” says Tyler Square, assistant professor of molecular genetics at the University of Florida, who was not involved in the study. The team behind the new work decided to re-examine conventional wisdom after a postdoctoral researcher in the lab produced microscopy images of lamprey embryos stained for neurons in the animals’ gut. The stain highlighted some “small sort of concentrations of cells” that looked a lot like sympathetic neurons, recalls lead investigator Marianne Bronner, professor of biology at the California Institute of Technology. “I said, ‘Oh, those shouldn’t be there.’ So then we decided to delve deeper into it.” The unexpected neurons express several key genes—specifically ASCL1, PHOX2 and HAND—involved in the sympathoadrenal system, the team discovered using a suite of techniques, including immunohistochemistry, in situ hybridization chain reaction and RNA sequencing. These are “all transcription factors that are known to be important in sympathetic neuron differentiation in mammals,” Bronner says. © 2024 Simons Foundation

Keyword: Stress; Evolution
Link ID: 29270 - Posted: 04.26.2024