Chapter 15. Emotions, Aggression, and Stress

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By Olga Perepelkina, Kristina Astakhova We all remember “the dress.” An illusion like this shows that even a phenomenon as basic as color perception can be ambiguous. Emotions are much more complex entities than colors and thus can lead to even more confusion. Our perception of emotional expressions is related not only to the physical properties of a face, but also to a bunch of other factors affecting both the percipient (for example, a person's past experience, cultural background, or individual expectations) and the situation itself (the context). To test that idea, researchers at Neurodata Lab created a short test and asked more than 1,400 people from 29 countries to have a look at four pairs of photographs, or eight in total. The first image in each pair showed a woman with a certain facial expression. The second was identical to the first, except that it had an object added to it: a mascara brush, a book and glasses, a toothpick or a guitar. These objects added context. People then had to look at every image and indicate if the facial expressions looked emotional to them. Responses differed significantly between the photos with an added object and those without one. On average, people responded that the faces were “emotional” in most images without any additional context (in 3.52 out of four). After an object was added, subjects frequently changed their opinions and instead responded that emotions were present in only one about photo out of four (to be precise, it was 1.2 out of four). Emotional perception depends on context in the broadest sense of this word. The way we express ourselves nonverbally is affected by an array of factors, such as individual differences in age, gender, society or culture, and differences in various situational factors. © 2019 Scientific American

Keyword: Emotions
Link ID: 26612 - Posted: 09.15.2019

By Emily Underwood Adrenaline. The word is synonymous with any activity that gets our blood racing, whether it be encountering a rattlesnake or watching the latest horror movie. But a new study reveals that when it comes with our body’s stress response, adrenaline may be less important than another hormone, one that seeps out of our bones. Our skeleton is much more than a rigid scaffold for the body, says geneticist Gérard Karsenty of Columbia University. Our bones secrete a protein called osteocalcin, discovered in the 1970s, that rebuilds the skeleton. In 2007, Karsenty and colleagues discovered that this protein acts as a hormone to keep blood sugar levels in check and burn fat. Later, his group showed that the hormone is important for maintaining brain function and physical fitness, restoring memory in aged mice and boosting performance during exercise in old mice and people. The findings led Karsenty to hypothesize that animals evolved bony skeletons to escape danger. The new study furthers that argument. Karsenty and colleagues exposed mice to several stressors, including a mild electric shock to the foot and a whiff of fox urine, a scent that triggers an innate fear response. Then, the researchers measured the osteocalcin in the animals’ blood. Within 2 to 3 minutes of being exposed to a stressor, levels of osteocalcin in the mice quadrupled, the team reports today in Cell Metabolism. A classic stressor in people had a similar effect: When the researchers asked volunteers to speak in front of an audience, osteocalcin levels also spiked. © 2019 American Association for the Advancement of Science

Keyword: Hormones & Behavior; Stress
Link ID: 26609 - Posted: 09.13.2019

By Roni Dengler | Testosterone often gets a bad rap. The hormone responsible for male sexual development has been linked in studies to aggression and a lack of empathy. People with autism – a developmental condition that can lead to anxiety and trouble interacting with others – also have a hard time empathizing. Since the condition is four times more common in boys than girls, scientists once thought testosterone might reduce our ability to tell how others are feeling. But now, researchers find that’s not the case. “Of course, the primary suspect when we have something that is sharply differentiated by sex is testosterone,” University of Pennsylvania marketing professor Gideon Nave, who led the work, said in a press release. In the new study, Nave and colleagues report men given extra testosterone were able to read emotions just as well as those with typical hormone levels. The findings contrast a prevailing hypothesis that testosterone challenges men’s ability to empathize. Emotional Eyes In previous studies, other scientists tested whether testosterone influences empathy. They gave a few dozen women testosterone and then tested their ability to infer emotions by looking at pictures of people’s eyes. The studies concluded the testosterone lowered the women’s ability to empathize. The findings lent support for what’s known as the “extreme male brain hypothesis.” The hypothesis posits that men and women process and experience the world differently – women empathize and men systemize. Another study linking prenatal testosterone levels to autism added weight to the hypothesis.

Keyword: Hormones & Behavior; Emotions
Link ID: 26603 - Posted: 09.12.2019

/ By Rod McCullom In recent years, a steadily increasing volume of data has demonstrated that peer victimization — the clinical term for bullying — impacts hundreds of millions of children and adolescents, with the effects sometimes lasting years and, possibly, decades. The problem is even recognized as a global health challenge by the World Health Organization and the United Nations. And yet, researchers maintain there is still a limited understanding of how the behavior may physically shape the developing brain. Researchers believe more than 3.2 million American students experience bullying every year. That’s about 1 percent of the nation’s total population. Bullying is usually defined as repeated and intentional verbal, physical, and anti-social behavior that seeks to intimidate, harm, or marginalize someone perceived as smaller, weaker, or less powerful. Among younger children, common forms of bullying include abusive language and physical harm. This behavior may grow subtler with age as adolescent bullies routinely exclude, insult, and mock their targets. Sometimes this behavior escalates into “mobbing” among groups of bullies in school, work, or cyberspace. Researchers believe more than 3.2 million American students experience bullying every year. That’s about 1 percent of the nation’s total population. Among these students, about 10 to 15 percent experience “chronic” or persistent bullying that will last more than six continuous months. Experiencing chronic peer victimization is associated with lower academic achievement, higher unemployment rates, depression, anxiety, post-traumatic stress disorder, substance abuse, and self-harm and suicidal thoughts. Copyright 2019 Undark

Keyword: Aggression; Development of the Brain
Link ID: 26596 - Posted: 09.10.2019

The children of women who experience severe stress when pregnant are nearly 10 times more likely to develop a personality disorder by the age of 30, a study suggests. Even moderate prolonged stress may have an impact on child development and continue after a baby's birth, it said. More than 3,600 pregnant women in Finland were asked about their stress levels, and their children followed up. Psychiatrists say mums-to-be must have access to mental health support. Other important factors, such as how children are brought up, the family's financial situation and trauma experienced during childhood, are known to contribute to the development of personality disorders and could have played a role. What is a personality disorder? It means that certain aspects of someone's personality make life difficult for them and for other people. They can be overly anxious or emotionally unstable, for example, or paranoid or anti-social - there are a wide range of types. Personality disorders are thought to affect about one in 20 people. They are more likely to have other mental health problems, such as depression, or drug and alcohol problems. Like other mental disorders, upbringing, brain problems and genes can play a part in their development. What did the study do? Every month during pregnancy, the study - in the British Journal of Psychiatry - asked women to answer questions about their mental stress levels. They had to say if they had notable stress, some stress or no stress. The women lived around Helsinki, Finland, and their babies were born between 1975 and 1976. When those children turned 30, any diagnoses of personality disorder were noted - there were 40 in total, which were all severe cases involving admission to hospital. © 2019 BBC

Keyword: Stress; Development of the Brain
Link ID: 26578 - Posted: 09.06.2019

By Rachel Zamzow One night in December 2013, Hans Korbmacher awoke in a fury. The book-loving, introverted 10-year-old was feverish, agitated and gnawing on his tongue. He headed downstairs, leaped onto an ottoman and threw his hands over his head, startling his parents. He was “clearly not present,” says his mother, Heather Korbmacher. When the same thing happened two weeks later, she thought fevers may have induced Hans’ bizarre behavior. A nurse said it could be the flu. Meanwhile, Hans’ condition worsened. He was anxious and volatile. His handwriting, once a model of penmanship, morphed into angry scribbles. And he became a peculiarly picky eater. Korbmacher, a behavioral specialist for schools in Bellingham, Wash., tried to manage Hans’ symptoms on her own. “It was working OK during those first five months, until it was absolutely not,” she says. Extreme rages came weekly and then daily, keeping Hans out of school. He punched holes in walls and ripped down curtains. The worst part: Hans was acutely aware that something was very wrong. He pleaded with his parents to make it stop. “He would beg us to kill him,” Korbmacher says. Several doctors’ appointments later, a psychiatrist suggested that Hans’ symptoms stemmed from obsessive-compulsive disorder, or OCD. The diagnosis seemed off base to Korbmacher until she read online about a rare form of OCD with a mouthful of a name: pediatric autoimmune neuropsychiatric disorder associated with streptococcal infections, or PANDAS for short. Hans had all but one of the listed symptoms. Korbmacher immediately had Hans tested for a strep infection. A throat swab came back negative, but blood tests revealed that he had four times the typical levels of immune molecules that the body produces in response to a strep infection. © Society for Science & the Public 2000–2019.

Keyword: OCD - Obsessive Compulsive Disorder; Neuroimmunology
Link ID: 26542 - Posted: 08.26.2019

Natalie Parletta Poor air quality has been associated with higher rates of bipolar disorder and major depression in observational research involving more than 150 million people in the US and Denmark. The link was found to be more pronounced in Denmark, with research also suggesting that pollution exposure during childhood more than doubled the risk of schizophrenia and personality disorders. Genetic studies now reveal that genes only explain a small fraction of psychiatric illness onset. Therefore, researchers are exploring environmental factors in the search to comprehend the global increase in these complex disorders of brain function. “We were hoping to understand what aspects of human environments are driving psychiatric and neurological disease prevalence,” says senior author Andrey Rzhetsky from the University of Chicago, US. The findings are published in the journal PLOS ONE. The search thus far has focussed largely on family environments and childhood trauma, including prenatal influences. Other possible avenues include social circumstances, stressful life events, substance abuse, and emerging evidence for poor diet. Far less attention has been given to physical environments. Yet as the numerous adverse health impacts of air pollution have come to light, inspection of its potential role in neurological disorders has lagged.

Keyword: Schizophrenia; Neurotoxins
Link ID: 26525 - Posted: 08.21.2019

A new study analyzing samples from patients with and without acute flaccid myelitis (AFM) provides additional evidence for an association between the rare but often serious condition that causes muscle weakness and paralysis, and infection with non-polio enteroviruses. The National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, funded the research, which was conducted by investigators at Columbia University’s Center for Infection and Immunity and investigators from the Centers for Disease Control and Prevention. The findings are reported in the online journal mBio. There have been 570 confirmed cases since CDC began tracking AFM in August 2014. AFM outbreaks were reported to the CDC in 2014, 2016 and 2018. AFM affects the spinal cord and is characterized by the sudden onset of muscle weakness in one or more limbs. Spikes in AFM cases, primarily in children, have coincided in time and location with outbreaks of EV-D68 and a related enterovirus, EV-A71. Both of these viruses typically cause mild respiratory illness from which most people recover fully. Despite the epidemiological link between enterovirus circulation and AFM cases, evidence of direct causality has not been found. The researchers first looked for direct evidence of enterovirus infection in the cerebrospinal fluid (CSF) of 13 children and one adult diagnosed with AFM in 2018. They also examined five CSF samples taken from people with other central nervous system diseases. The team used a new tool they developed called VirCapSeq-VERT, which can detect any viral genetic material that is at least 60% like that of any known vertebrate virus. They found enteroviral genetic material (EV-A71) in only the one adult AFM case and genetic material from another enterovirus (echovirus 25) in one of the non-AFM cases.

Keyword: Movement Disorders; Neuroimmunology
Link ID: 26493 - Posted: 08.13.2019

Sacha Pfeiffer There's a new smell tingling tourists' noses in the Big Apple, far above the trash bag-lined sidewalks — and this scent is by design. Atop One World Trade Center, New York City's tallest building, a fragrance carrying hints of citrus, beech trees and red maples wafts through the glass-enclosed observatory deck. When the observatory commissioned the custom scent to diffuse through the floor's HVAC system, Managing Director Keith Douglas told the New York Times that he wanted it to elicit a "positive thought," and offer a "a subtle complement to the experience" of visiting the space. But not everyone is keen on the scent. One tourist described the smell as "sickly," according to the Times, which first documented the new aromatic experience in lower Manhattan. It's a marketing strategy businesses are increasingly deploying to lure customers into stores and entice them to stay longer. The smell of cinnamon fills Yankee Candle stores, Subway pumps a doughy bread scent through its vents. International Flavors & Fragrances, the same company that developed clothing chain Abercrombie & Fitch's notoriously pungent "Fierce" cologne, known to linger on clothes long after their purchase, designed One World's scent. "The quickest way to change somebody's mood or behavior is with smell," says Dr. Alan Hirsch, neurological director of the Smell and Taste Treatment and Research Foundation in Chicago. © 2019 npr

Keyword: Chemical Senses (Smell & Taste); Emotions
Link ID: 26487 - Posted: 08.12.2019

By Iliana Magra LONDON — On a spring afternoon last year, Neil Fraser was walking down the main shopping street in Aberdeen, a port city in northeastern Scotland, when something strange happened. The bacon-and-chicken sandwich he was halfway through eating suddenly vanished from his hand. The culprit? A hungry bird he hadn’t seen coming. “The sea gull flew in from behind me,” Mr. Fraser, a manager at the Old Schoolhouse pub in the city, said by phone on Wednesday. The bird knocked down his hand and, before he realized what was happening, it was all over: “The sandwich and the sea gull were both gone.” Aggressive gulls trying to snatch people’s food, and at times succeeding, have been a longstanding nuisance in Britain, and various solutions have been proposed over the years, including not feeding the birds, holding a stick or umbrella overhead and installing wires on roofs that they use for nesting. The Old Schoolhouse pub even reportedly offered customers water pistols to deflect the birds. Now, new research proposes a different approach: staring them down. A study published in the journal Biology Letters on Wednesday by the Royal Society, the world’s oldest continuous scientific society, suggested that making eye contact might be key to fending off herring gulls, a familiar sight in British seaside towns. The study, conducted late last year in coastal towns in Cornwall, in southwestern England, focused on that species, which are white-, gray- and black-feathered, with beaks of yellow and red. The researchers tried to test 74 birds by placing potato chips in front of an experimenter. Just 27 of the gulls bit the bait — a factor that the research team attributed to whether the experimenter was facing toward or away from the gull. © 2019 The New York Times Company

Keyword: Aggression; Evolution
Link ID: 26486 - Posted: 08.12.2019

Hope Reese Patricia S. Churchland is a key figure in the field of neurophilosophy, which employs a multidisciplinary lens to examine how neurobiology contributes to philosophical and ethical thinking. In her new book, “Conscience: The Origins of Moral Intuition,” Churchland makes the case that neuroscience, evolution, and biology are essential to understanding moral decision-making and how we behave in social environments. In the past, “philosophers thought it was impossible that neuroscience would ever be able to tell us anything about the nature of the self, or the nature of decision-making,” the author says. The way we reach moral conclusions, Churchland asserts, has a lot more to do with our neural circuitry than we realize. The way we reach moral conclusions, she asserts, has a lot more to do with our neural circuitry than we realize. We are fundamentally hard-wired to form attachments, for instance, which greatly influence our moral decision-making. Also, our brains are constantly using reinforcement learning — observing consequences after specific actions and adjusting our behavior accordingly. Churchland, who teaches philosophy at the University of California, San Diego, also presents research showing that our individual neuro-architecture is heavily influenced by genetics: political attitudes, for instance, are 40 to 50 percent heritable, recent scientific studies suggest. Copyright 2019 Undark

Keyword: Consciousness; Emotions
Link ID: 26480 - Posted: 08.02.2019

Susie Neilson Living with anxiety can be tough — your thoughts might race, you might dread tasks others find simple (like driving to work) and your worries might feel inescapable. But loving someone with anxiety can be hard too. You might feel powerless to help or overwhelmed by how your partner's feelings affect your daily life. If so, you're not alone: Multiple studies have shown that anxiety disorders may contribute to marital dissatisfaction. "We often find that our patients' ... partners are somehow intertwined in their anxiety," says Sandy Capaldi, associate director at the Center for the Treatment and Study of Anxiety at the University of Pennsylvania. Anxiety is experienced at many different levels and in different forms — from moderate to debilitating, from generalized anxiety to phobias — and its impacts can vary. But psychiatrists and therapists say there are ways to help your partner navigate challenges while you also take care of yourself. Start by addressing symptoms. Because an anxiety disorder can be consuming, it can be best to start by talking with your partner about the ways anxiety affects daily life, like sleeplessness, says Jeffrey Borenstein, president and CEO of the Brain & Behavior Research Foundation in New York. Something as simple as using the word "stress" instead of clinical labels can help too. "Often people may feel a little more comfortable talking about stress as opposed to ... anxiety [disorders]," Borenstein says. Don't minimize feelings. "Even if the perspective of the other person absolutely makes no sense to you logically, you should validate it," says Carolyn Daitch, a licensed psychologist and director of the Center for the Treatment of Anxiety Disorders in Farmington Hills, Mich. Try to understand your partner's fears and worries, or at least acknowledge that those fears and worries are real to your partner, before addressing why such things might be irrational. © 2019 npr

Keyword: Stress
Link ID: 26456 - Posted: 07.27.2019

Tina Hesman Saey Subtle defects in the immune system may lead to obesity and type 2 diabetes, a study of mice suggests. Mice gained weight and developed health problems when they carried a genetic defect that dampens some immune functions, researchers report in the July 26 Science. The immune problems were linked to shifts in the gut microbiome — the collection of friendly bacteria and other microbes living in the intestines. Altering the gut microbe mix, particularly in the small intestine, may lead to increased absorption of fat from the diet, the researchers found. These findings, if they hold up in human studies, could lead to strategies for boosting immune system function in order to help prevent obesity and associated health problems. People with obesity and those with type 2 diabetes also have gut microbe compositions and subtle immune system deficiencies similar to those seen in the mice, says June Round, a microbiome researcher at the University of Utah School of Medicine in Salt Lake City. “It’s possible that things that are happening in our mice are also happening in individual [humans],” she says. Round and colleagues noticed that mice with a defect in the Myd88 gene started gaining weight at about 5 months old. By about a year old, those mice, which lack Myd88 protein in immune cells called T cells, weighed up to 60 grams — about twice as much as a normal mouse. The mutant mice also had developed metabolic problems associated with obesity, such as insulin resistance, a hallmark of type 2 diabetes in people. |© Society for Science & the Public 2000 - 2019

Keyword: Obesity; Neuroimmunology
Link ID: 26453 - Posted: 07.26.2019

By Andrew Curry ZURICH, SWITZERLAND—The children living in SOS Children's Villages orphanages in Pakistan have had a rough start in life. Many have lost their fathers, which in conservative Pakistani society can effectively mean losing their mothers, too: Destitute widows often struggle to find enough work to support their families and may have to give up their children. The orphanages, in Multan, Lahore, and Islamabad, provide shelter and health care and send kids to local schools, trying to provide "the best possible support," says University of Zurich (UZH) physician and neuroscientist Ali Jawaid. "But despite that, these children experience symptoms similar to PTSD [post-traumatic stress disorder]," including anxiety and depression. Beyond these psychological burdens, Jawaid wonders about a potential hidden consequence of the children's experience. He has set up a study with the orphanages to probe the disturbing possibility that the emotional trauma of separation from their parents also triggers subtle biological alterations—changes so lasting that the children might even pass them to their own offspring. That idea would have been laughed at 20 years ago. But today the hypothesis that an individual's experience might alter the cells and behavior of their children and grandchildren has become widely accepted. In animals, exposure to stress, cold, or high-fat diets has been shown to trigger metabolic changes in later generations. And small studies in humans exposed to traumatic conditions—among them the children of Holocaust survivors—suggest subtle biological and health changes in their children. © 2019 American Association for the Advancement of Science.

Keyword: Epigenetics; Stress
Link ID: 26432 - Posted: 07.19.2019

Sara Reardon Nearly every scientist who has used mice or rats to study depression is familiar with the forced-swim test. The animal is dropped into a tank of water while researchers watch to see how long it tries to stay afloat. In theory, a depressed rodent will give up more quickly than a happy one — an assumption that has guided decades of research on antidepressants and genetic modifications intended to induce depression in lab mice. But mental-health researchers have become increasingly sceptical in recent years about whether the forced-swim test is a good model for depression in people. It is not clear whether mice stop swimming because they are despondent or because they have learnt that a lab technician will scoop them out of the tank when they stop moving. Factors such as water temperature also seem to affect the results. “We don’t know what depression looks like in a mouse,” says Eric Nestler, a neuroscientist at the Icahn School of Medicine at Mount Sinai in New York City. Now, the animal-rights group People for the Ethical Treatment of Animals (PETA) is jumping into the fray. The group wants the US National Institute of Mental Health (NIMH) in Bethesda, Maryland, to stop supporting the use of the forced-swim test and similar behavioural assessments by its employees and grant recipients. The tests “create intense fear, anxiety, terror, and depression in small animals” without providing useful data, PETA said in a letter to the agency on 12 July. © 2019 Springer Nature Publishing AG

Keyword: Depression; Animal Rights
Link ID: 26431 - Posted: 07.19.2019

By Bridget Alex Whether animal, vegetable, mineral or machine, everything experiences stress — broadly defined as challenges to equilibrium, a balanced state of being. The Human Stress Story In biology, stress is the body’s response to perceived threats to our physical or mental well-being. Moderate amounts are healthy and normal. But too much — or too little — causes problems. Chronic stress is linked to cardiovascular disease, anxiety and depression. Stress associated with extreme events such as combat can lead to post-traumatic stress disorder (PTSD). Symptoms of PTSD, which affects over 7 million Americans, include flashbacks and hypervigilance long after a trauma. Meanwhile, recent studies show that people who underreact to stress are more likely to have impulsive behavior and substance addiction. The Adaptive Stress Response A 1936 Nature paper launched the field of stress research. In the study, physician Hans Seyle — later called the father of stress — subjected rats to cold, drugs, excessive exercise and other assaults. Whatever the stimuli, the rats exhibited similar physiological effects. Now understood as the stress response, this set of bodily changes is an adaptation that allows animals to focus their energy on survival and forgo other matters such as growth or reproduction. It’s initiated when the brain detects a potential threat and launches a cascade of hormones, including adrenaline and cortisol, that affects the endocrine, nervous and immune systems.

Keyword: Stress
Link ID: 26399 - Posted: 07.09.2019

Maria Temming A new analysis of brain scans may explain why hyperrealistic androids and animated characters can be creepy. By measuring people’s neural activity as they viewed pictures of humans and robots, researchers identified a region of the brain that seems to underlie the “uncanny valley” effect — the unsettling sensation sometimes caused by robots or animations that look almost, but not quite, human (SN Online: 11/22/13). Better understanding the neural circuitry that causes this feeling may help designers create less unnerving androids. In research described online July 1 in the Journal of Neuroscience, neuroscientist Fabian Grabenhorst and colleagues took functional MRI scans of 21 volunteers during two activities. In each activity, participants viewed pictures of humans, humanoid robots of varying realism and — to simulate the appearance of hyperrealistic robots — “artificial humans,” pictures of people whose features were slightly distorted through plastic surgery and photo editing. In the first activity, participants rated each picture on likability and how humanlike the figures appeared. Next, participants chose between pairs of these pictures, based on which subject they would rather receive a gift from. In line with the uncanny valley effect, participants generally rated more humanlike candidates as more likable, but this trend broke down for artificial humans — the most humanlike of the nonhuman options. A similar uncanny valley trend emerged in participants’ judgments about which figures were more trustworthy gift-givers. |© Society for Science & the Public 2000 - 2019.

Keyword: Attention; Emotions
Link ID: 26387 - Posted: 07.04.2019

Laura Sanders Immune cells can storm into the brains of older mice, where these normally helpful cells seem to be up to no good. The result, described July 3 in Nature, raises the possibility that immune cells may have a role in aging. Anne Brunet of Stanford University School of Medicine and colleagues studied gene activity to identify all sorts of cells in a particular spot in mice brains — the subventricular zone, where new nerve cells are born. Compared with young mice, old mice had many more killer T cells in that area. These immune system fighters take out damaged or infected cells in the rest of the body, but aren’t usually expected to show up in the brain. Experiments on postmortem human brain tissue suggest that a similar thing happens in old people. T cells were more abundant in tissue from people ages 79 to 93 than in tissue from people ages 20 to 44, the researchers found. In the brains of mice, killer T cells churn out a compound called interferon-gamma. This molecule might be responsible for the falling birthrate of new nerve cells that comes with old age, experiments on mice’s stem cells in dishes suggest. The results come amid a debate over whether human brains continue to make new nerve cells as adults (SN Online: 3/8/2018). If so, then therapies that shut T cells out of the brain might help keep nerve cell production rates high, even into old age — a renewal that might stave off some of the mental decline that comes with aging. |© Society for Science & the Public 2000 - 2019

Keyword: Alzheimers; Neuroimmunology
Link ID: 26385 - Posted: 07.04.2019

By Bret Stetka The pathology of a stroke is deceptively complicated. In the simplest sense, strokes occur when the blood supply to a particular region of the brain is interrupted, cutting off the area to oxygen and nutrients. This deprivation results in injury and death to the local brain cells. But for days after the breach in blood flow, the immune system also does its own fair share of damage to the already injured brain through an inflammatory response. New research by a group at Stanford University has identified a subset of immune cells that drive brain injury following a stroke, raising the possibility that immune-system inhibition might be a promising treatment for a blood-deprived brain. More surprising is that much of the immune reaction to a stroke appears to begin in the gut, shedding new light on our ever evolving understanding of the gut-brain axis. The research was published on July 1 in Nature Immunology. Strokes manifest in two ways: either an artery in the brain bursts—causing a hemorrhagic stroke—or it becomes clogged, typically by a blood clot, causing the far more common ischemic stroke. In the new study, the authors used positron-emission tomography to scan immune system activity in mice that had the blood in a single cerebral artery interrupted for 45 minutes, mimicking an ischemic stroke. © 2019 Scientific American

Keyword: Stroke; Neuroimmunology
Link ID: 26381 - Posted: 07.03.2019

Maanvi Singh The notion that you can smile your way to happiness is an enduring one. Back in the 1800s, Charles Darwin was among the first to come up with what modern scientists further developed into the "facial feedback hypothesis." That's the idea that smiling can make you happier and frowning can make you sadder or angrier — that changing your facial expression can intensify or even transform your mood. Dick Van Dyke sang about the phenomenon — and so did Nat King Cole. And it is still taught in psychology classes today. But researchers are now finding that this phenomenon may be more complicated than they once thought. A recent study that reviewed around 50 years of data, including the results of nearly 300 experiments testing the facial feedback theory, has found that if smiling boosts happiness, it's only by a tiny bit. "I know when I'm sad and people tell me to smile, it just makes me more angry." Nick Coles, social psychology researcher, University of Tennessee, Knoxville After crunching all the numbers, the researchers say their results suggest that if 100 people smiled — all else equal among them — only about seven might expect to feel happier than if they hadn't smiled. The study also looked at the effects of a number of other facial expressions, including scowling and frowning, and tried to more generally understand the extent to which positive facial expressions create positive emotions and negative facial expressions create negative emotions. In each case, "the effects were extremely tiny," says Nick Coles, a social psychology Ph.D. candidate at the University of Tennessee, Knoxville, who led the study. The results, published in the June issue of Psychological Bulletin, add to a debate that has been ongoing "for at least 100 years — since the dawn of psychology," Coles says. © 2019 npr

Keyword: Emotions
Link ID: 26370 - Posted: 07.01.2019