Chapter 11. Emotions, Aggression, and Stress

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by Charles Q. Choi Infection during pregnancy may be associated with having an autistic child simply because mothers of autistic children are prone to infections, a new study finds. The results suggest that “common infections during pregnancy do not seem increase their children’s risk of autism,” says study investigator Martin Brynge, a psychiatrist and doctoral student of global public health at the Karolinska Institutet in Stockholm, Sweden. “Prevention of maternal infections would likely not affect the prevalence of autism in the population.” A great deal of previous research has linked maternal infection during pregnancy with autism and intellectual disability in children. Whether the former causes the latter, however, has remained uncertain. For instance, both autism and intellectual disability are linked with gene variants that may influence the immune system, so mothers of children with either condition may also just be more vulnerable to serious infections. The new study analyzed data from 549,967 children, including 267,995 girls, living in Stockholm County who were born between 1987 and 2010; about 34,000 of the children had been exposed to a maternal infection requiring specialized health care, according to data from Sweden’s National Patient Register and National Medical Birth Register. Of the exposed children, 3.3 percent have autism, compared with 2.5 percent of unexposed children — a 16 percent increase in the chance of autism. But maternal infection in the year before pregnancy was also linked with a 25 percent greater chance of autism. “Mothers who had an infection during pregnancy may not be comparable to those mothers without infections,” Brynge says. “There may be systematic differences at the group level.” © 2022 Simons Foundation

Keyword: Autism; Neuroimmunology
Link ID: 28488 - Posted: 09.24.2022

By Rodrigo Pérez Ortega There’s clear evidence that racial discrimination negatively affects the health of people of color over the course of their lives. It’s associated with depression, anxiety, and psychological stress; it increases blood pressure; and it has been shown to weaken the immune system. However, few studies have linked single discriminatory events to immediate health effects. Now, data from a first-of-its-kind study suggest a racist attack could raise a person’s stress biomarkers almost immediately. “The big question mark, for me, has always been, how does this happen? What’s the black box that’s in the middle of discrimination, stress, and health disparities?” says Tiffany Yip, a developmental psychologist at Fordham University who was not involved with the study. “I think that this paper addresses that mechanistic question.” For the proof-of-concept study, Soohyun Nam at Yale University’s School of Nursing and her team collaborated with Black churches and their communities to recruit 12 Black people between the ages of 30 and 55 living in the northeastern United States. After accounting for the participants’ baseline stress levels, the research team adapted standardized survey questions about discrimination and microaggressions—such as whether they believed they had been mistaken for a service worker because of their race—and asked participants to share any occurrences of these experiences through a smartphone app. The method, known as ecological momentary assessment (EMA), has previously been used to study physical activity and behavior—such as alcohol intake reduction or smoking frequency. But this is one of the first studies correlating stress biomarkers and racist experiences using this precise monitoring technique. Researchers also asked the participants to describe their mood five times a day over the course of a week using the same phone app. To measure their biological response, participants spat into a tube four times a day over 4 days and froze the samples until research staff collected them. The researchers then had the samples analyzed in the lab to measure levels of cortisol, a hormone released during emotional distress, and alpha amylase, an enzyme that breaks down sugars and is secreted in stressful situations.

Keyword: Stress; Hormones & Behavior
Link ID: 28481 - Posted: 09.17.2022

Yasemin Saplakoglu You’re on the vacation of a lifetime in Kenya, traversing the savanna on safari, with the tour guide pointing out elephants to your right and lions to your left. Years later, you walk into a florist’s shop in your hometown and smell something like the flowers on the jackalberry trees that dotted the landscape. When you close your eyes, the store disappears and you’re back in the Land Rover. Inhaling deeply, you smile at the happy memory. Now let’s rewind. You’re on the vacation of a lifetime in Kenya, traversing the savanna on safari, with the tour guide pointing out elephants to your right and lions to your left. From the corner of your eye, you notice a rhino trailing the vehicle. Suddenly, it sprints toward you, and the tour guide is yelling to the driver to hit the gas. With your adrenaline spiking, you think, “This is how I am going to die.” Years later, when you walk into a florist’s shop, the sweet floral scent makes you shudder. “Your brain is essentially associating the smell with positive or negative” feelings, said Hao Li, a postdoctoral researcher at the Salk Institute for Biological Studies in California. Those feelings aren’t just linked to the memory; they are part of it: The brain assigns an emotional “valence” to information as it encodes it, locking in experiences as good or bad memories. And now we know how the brain does it. As Li and his team reported recently in Nature, the difference between memories that conjure up a smile and those that elicit a shudder is established by a small peptide molecule known as neurotensin. They found that as the brain judges new experiences in the moment, neurons adjust their release of neurotensin, and that shift sends the incoming information down different neural pathways to be encoded as either positive or negative memories. To be able to question whether to approach or to avoid a stimulus or an object, you have to know whether the thing is good or bad. All Rights Reserved © 2022

Keyword: Learning & Memory; Emotions
Link ID: 28471 - Posted: 09.10.2022

By Sujata Gupta Lack of sleep has been linked to heart disease, poor mood and loneliness (SN: 11/15/16). Being tired could also make us less generous, researchers report August 23 in PLOS Biology. The hour of sleep lost in the switch over to Daylight Savings Time every spring appears to reduce people’s tendency to help others, the researchers found in one of three experiments testing the link between sleep loss and generosity. Specifically, they showed that average donations to one U.S.-based nonprofit organization dropped by around 10 percent in the workweek after the time switch compared with four weeks before and after the change. In Arizona and Hawaii, states that do not observe Daylight Savings Time, donations remained unchanged. With over half of the people living in parts of the developed world reporting that they rarely get enough sleep during the workweek, the finding has implications beyond the week we spring forward, the researchers say. “Lack of sleep shapes the social experiences we have [and] the kinds of societies we live in,” says neuroscientist Eti Ben Simon of the University of California, Berkeley. To test the link between sleep loss and generosity, Ben Simon and her team first brought 23 young adults into the lab for two nights. The participants slept through one night and stayed awake for another night. In the mornings, participants completed a standardized altruism questionnaire rating their likelihood of helping strangers or acquaintances in various scenarios. For instance, participants rated on a scale from 1 to 5, with 1 for least likely to help and 5 for most likely, whether they would give up their seat on a bus to a stranger or offer a ride to a coworker in need. Participants never read the same scenario more than once. Roughly 80 percent of participants showed less likelihood of helping others when sleep-deprived than when rested. © Society for Science & the Public 2000–2022.

Keyword: Sleep; Emotions
Link ID: 28444 - Posted: 08.24.2022

By Ingrid Wickelgren For as long as she can remember, Kay Tye has wondered why she feels the way she does. Rather than just dabble in theories of the mind, however, Tye has long wanted to know what was happening in the brain. In college in the early 2000s, she could not find a class that spelled out how electrical impulses coursing through the brain’s trillions of connections could give rise to feelings. “There wasn’t the neuroscience course I wanted to take,” says Tye, who now heads a lab at the Salk Institute for Biological Studies in La Jolla, Calif. “It didn’t exist.” When she dedicated a chapter of her Ph.D. thesis to emotion, she was criticized for it, she recalls. The study of feelings had no place in behavioral neuroscience, she was told. Tye disagreed at the time, and she still does. “Where do we think emotions are being implemented—somewhere other than the brain?” Since then, Tye’s research team has taken a step toward deciphering the biological underpinnings of such ineffable experiences as loneliness and competitiveness. In a recent Nature study, she and her colleagues uncovered something fundamental: a molecular “switch” in the brain that flags an experience as positive or negative. Tye is no longer an outlier in pursuing these questions. Other researchers are thinking along the same lines. “If you have a brain response to anything that is important, how does it differentiate whether it is good or bad?” says Daniela Schiller, a neuroscientist at the Icahn School of Medicine at Mount Sinai in New York City, who wasn’t involved in the Nature paper. “It’s a central problem in the field.” The switch was found in mice in Tye’s study. If it works similarly in humans, it might help a person activate a different track in the brain when hearing an ice cream truck rather than a bear’s growl. This toggling mechanism is essential to survival because animals need to act differently in the contrasting scenarios. “This is at the hub of where we translate sensory information into motivational significance,” Tye says. “In evolution, it’s going to dictate whether you survive. In our modern-day society, it will dictate your mental health and your quality of life.” © 2022 Scientific American,

Keyword: Learning & Memory; Emotions
Link ID: 28436 - Posted: 08.13.2022

By Jonathan Moens In 1993, Julio Lopes was sipping a coffee at a bar when he had a stroke. He fell into a coma, and two months later, when he regained consciousness, his body was fully paralyzed. Doctors said the young man’s future was bleak: Save for his eyes, he would never be able to move again. Lopes would have to live with locked-in syndrome, a rare condition characterized by near-total paralysis of the body and a totally lucid mind. LIS is predominantly caused by strokes in specific brain regions; it can also be caused by traumatic brain injury, tumors, and progressive diseases like amyotrophic lateral sclerosis, or ALS. Yet almost 30 years later, Lopes now lives in a small Paris apartment near the Seine. He goes to the theater, watches movies at the cinema, and roams the local park in his wheelchair, accompanied by a caregiver. A small piece of black, red, and green fabric with the word “Portugal” dangles from his wheelchair. On a warm afternoon this past June, his birth country was slated to play against Spain in a soccer match, and he was excited. In an interview at his home, Lopes communicated through the use of a specialized computer camera that tracks a sensor on the lens of his glasses. He made slight movements with his head, selecting letters on a virtual keyboard that appeared on the computer’s screen. “Even if it’s hard at the beginning, you acquire a kind of philosophy of life,” he said in French. People in his condition may enjoy things others find insignificant, he suggested, and they often develop a capacity to see the bigger picture. That’s not to say daily living is always easy, Lopes added, but overall, he’s happier than he ever thought was possible in his situation. While research into LIS patients’ quality of life is limited, the data that has been gathered paints a picture that is often at odds with popular presumptions. To be sure, wellbeing evaluations conducted to date do suggest that up to a third of LIS patients report being severely unhappy. For them, loss of mobility and speech make life truly miserable — and family members and caregivers, as well as the broader public, tend to identify with this perspective. And yet, the majority of LIS patients, the data suggest, are much more like Lopes: They report being relatively happy and that they want very much to live. Indeed, in surveys of wellbeing, most people with LIS score as high as those without it, suggesting that many people underestimate locked-in patients’ quality of life while overestimating their rates of depression. And this mismatch has implications for clinical care, say brain scientists who study wellbeing in LIS patients.

Keyword: Consciousness; Emotions
Link ID: 28429 - Posted: 08.11.2022

By Erin Garcia de Jesús As Tanina Agosto went through her normal morning routine in July 2007, she realized something was wrong. The 29-year-old couldn’t control her left side, even her face. “Literally the top of my head to the bottom of my foot on the left side of my body could not feel anything.” The next day, Agosto spoke with a doctor at the New York City hospital where she works as a medical secretary. He told her that she probably had a pinched nerve and to see a chiropractor. But chiropractic care didn’t help. Months later, Agosto needed a cane to get around, and moving her left leg and arm required lots of concentration. She couldn’t work. Numbness and tingling made cooking and cleaning difficult. It felt a bit like looping a rubber band tightly around a finger until it loses sensation, Agosto says. Once the rubber band comes off, the finger tingles for a bit. But for her, the tingling wouldn’t stop. Finally, she recalls, one chiropractor told her, “I’m not too big of a person to say there’s something very wrong with you, and I don’t know what it is. You need to see a neurologist.” In November 2008, tests confirmed that Agosto had multiple sclerosis. Her immune system was attacking her brain and spinal cord. Agosto knew nothing about MS except that a friend of her mother’s had it. “At the time, I was like, there’s no way I’ve got this old lady’s condition,” she says. “To be hit with that and know that there’s no cure — that was just devastating.” Why people develop the autoimmune disorder has been a long-standing question. Studies have pointed to certain gene variations and environmental factors. For decades, a common virus called Epstein-Barr virus has also been high on the list of culprits. © Society for Science & the Public 2000–2022.

Keyword: Multiple Sclerosis; Neuroimmunology
Link ID: 28428 - Posted: 08.11.2022

By Virginia Morell In the summer of 2013, dolphin researcher Nicole Danaher-Garcia spotted something rare and remarkable in the animal world. As she stood on top of the bridge of a sport fishing yacht near Bimini in the Bahamas, she spied 10 adult Atlantic spotted dolphins she had never seen before—speeding into the waters of another group of dolphins. Most mammals attack intruders, but war wasn’t on the menu that day. Instead, the newcomers—eventually 46 in all—joined up with the resident dolphins, some 120 in number. Today, the two groups of Atlantic spotted dolphins (Stenella frontalis) have partially integrated, diving and swimming together, forming fast friendships, and likely even mating. It’s a “striking” display of tranquility between animals scientists usually consider rivals, says Richard Wrangham, a primatologist at Harvard University who was not involved with the study. Most mammals fight to protect mates and other resources if they encounter strangers entering their territory, he notes. This research, he says, may ultimately lead to a better understanding of the evolution of peacefulness. Danaher-Garcia, a behavioral ecologist, and her colleagues at the Dolphin Communication Project observed the two groups of dolphins in Bimini for 5 years, carrying out nearly 300 surveys. At first, the scientists only saw one small group of mixed Bimini and newcomer dolphins. But the next year, the scientists spotted a larger group of males and females of all ages from both communities mixing without “any signs of aggression,” she says. The dolphins continued their friendly behaviors through 2018, leading the team to suspect the two groups were merging. (Because of COVID-19 concerns, the scientists put their studies on hold in 2020.) The scientists discovered the newcomers had migrated from Little Bahama Bank, an area some 160 kilometers to the north known for its shallow seas, coral reefs, and sand banks. They were part of the White Sand Ridge (WSR) spotted dolphin community that another scientific team has been studying since the mid-1980s. © 2022 American Association for the Advancement of Science.

Keyword: Aggression; Sexual Behavior
Link ID: 28419 - Posted: 08.03.2022

By S. Hussain Hussain Ather You reach over a stove to pick up a pot. What you didn’t realize was that the burner was still on. Ouch! That painful accident probably taught you a lesson. It’s adaptive to learn from unexpected events so that we don’t repeat our mistakes. Our brain may be primed to pay extra attention when we are surprised. In a recent Nature study, researchers at the Massachusetts Institute of Technology found evidence that a hormone, noradrenaline, alters brain activity—and an animal’s subsequent behavior—in these startling moments. Noradrenaline is one of several chemicals that can flood the brain with powerful signals. Past research shows that noradrenaline is involved when we are feeling excited, anxious or alert and that it contributes to learning. But the new research shows it plays a strong role in responses to the unexpected. The M.I.T. team used a method called optogenetics to study noradrenaline in mice. The scientists added special light-sensitive proteins to neurons that work as an “off switch” for the cells when hit by pulses of laser light. They focused on modifying a brain area called the locus coeruleus, which holds cells responsible for releasing noradrenaline. With lasers, the researchers were able to stop these cells from producing the hormone in specific circumstances. They combined this method with photo tagging, a technique in which proteins flash with light, allowing the scientists to observe activity in the locus coeruleus cells and then determine how much noradrenaline was produced. Then the researchers designed a trial-and-error learning task for the rodents. The mice could push levers when they heard a sound. There were two sounds. After high-frequency tones of about 12 kilohertz, mice that pushed a lever were rewarded with water they could drink. For low-frequency tones, around four kilohertz, the mice that hit the lever got a slightly unpleasant surprise: a discomforting puff of air was blown at them. Over time, mice learned to push the lever only when they heard high-frequency tones because they got water when they did so. They avoided the lever when they heard low-frequency tones. © 2022 Scientific American

Keyword: Attention; Emotions
Link ID: 28412 - Posted: 07.30.2022

by Charles Q. Choi Children with autism show atypical development of brain regions connected to the amygdala, an almond-size brain structure involved in processing fear and other emotions, a new study finds. The brain regions most affected vary between autistic boys and girls, the study also shows, adding to the growing body of evidence for sex differences in autism, researchers say. “Better understanding of amygdala development and its connectivity can aid in the development of novel biomarkers to study brain and social health,” says Emma Duerden, assistant professor of applied psychology at Western University in London, Canada, who was not involved in the study. The amygdala is a central hub for brain circuits involved in social function. Previous studies have found it to be enlarged in some autistic children compared with non-autistic children, a difference that may be linked with anxiety and depression. In the new study, researchers used structural magnetic resonance imaging to track the growth of 32 brain regions with direct connections to the amygdala. The study participants included 282 autistic children, 93 of whom are female, and 128 non-autistic children, 61 of whom are female. The researchers scanned each child up to four times — when the children were 39, 52, 64 and 137 months old, on average. They also measured the children’s autism traits and social difficulties using a questionnaire filled out by parents, called the Social Responsiveness Scale-2. Autistic children had larger amygdala-connected brain regions than non-autistic children at all ages. The differences grew over time and were most apparent among the autistic children with prominent social difficulties. The researchers found no differences in the size of brain areas not directly connected to the amygdala between children with and without autism. © 2022 Simons Foundation

Keyword: Autism; Emotions
Link ID: 28398 - Posted: 07.14.2022

By Rachel Nuwer Whether we’ve got the flu or have had too much to drink, most of us have experienced nausea. Unlike other universal sensations such as hunger and thirst, however, scientists still don’t understand the biology behind the feeling—or how to stop it. A new study in mice identifies a possible key player: specialized brain cells that communicate with the gut to turn off the feeling of nausea. It’s an “elegant” study, says Nancy Thornberry, CEO of Kallyope, a biotechnology company focused on the interplay between the gut and the brain. Further research is needed to translate the finding into antinausea therapies, says Thornberry, who was not involved with the work, but the data suggest possible leads for designing new interventions. To conduct the research, Chuchu Zhang, a neuroscience postdoc at Harvard University, and her colleagues focused on the “area postrema,” a tiny structure in the brainstem first linked to nausea in the 1950s. Electrical stimulation of the region induces vomiting in animals. Last year, Zhang’s team identified two types of specialized excitatory neurons in the area postrema that induce nausea behavior in mice. Rodents can’t throw up, but they curl up in discomfort when they feel nauseous. Zhang and her colleagues showed the excitatory neurons in the area postrema are responsible for these behaviors by stimulating the cells. Genetic sequencing of cells in the area postrema also revealed inhibitory neurons in the region, which the scientists suspected may suppress the activity of the excitatory neurons and play a role in stopping the feeling of nausea. So in the new study, Zhang’s team injected mice with glucose insulinotropic peptide (GIP), a gut-derived hormone that humans and other animals produce after we ingest sugar and fat. Previous research in ferrets has shown GIP inhibits vomiting, and Zhang hypothesizes it may suppress nausea to prevent us from losing precious nutrients. She also thought it might play a role in activating nausea-inhibiting neurons. © 2022 American Association for the Advancement of Science.

Keyword: Miscellaneous
Link ID: 28384 - Posted: 06.30.2022

By Rachel Yehuda Rachel Yehuda is a professor of psychiatry and neuroscience and director of the Center for Psychedelic Psychotherapy and Trauma Research at the Icahn School of Medicine at Mount Sinai. She is also director of mental health at the James J. Peters Veterans Affairs Medical Center. Credit: Nick Higgins After the twin towers of the World Trade Center collapsed on September 11, 2001, in a haze of horror and smoke, clinicians at the Icahn School of Medicine at Mount Sinai in Manhattan offered to check anyone who'd been in the area for exposure to toxins. Among those who came in for evaluation were 187 pregnant women. Many were in shock, and a colleague asked if I could help diagnose and monitor them. They were at risk of developing post-traumatic stress disorder, or PTSD—experiencing flashbacks, nightmares, emotional numbness or other psychiatric symptoms for years afterward. And were the fetuses at risk? My trauma research team quickly trained health professionals to evaluate and, if needed, treat the women. We monitored them through their pregnancies and beyond. When the babies were born, they were smaller than usual—the first sign that the trauma of the World Trade Center attack had reached the womb. Nine months later we examined 38 women and their infants when they came in for a wellness visit. Psychological evaluations revealed that many of the mothers had developed PTSD. And those with PTSD had unusually low levels of the stress-related hormone cortisol, a feature that researchers were coming to associate with the disorder. Surprisingly and disturbingly, the saliva of the nine-month-old babies of the women with PTSD also showed low cortisol. The effect was most prominent in babies whose mothers had been in their third trimester on that fateful day. Just a year earlier a team I led had reported low cortisol levels in adult children of Holocaust survivors, but we'd assumed that it had something to do with being raised by parents who were suffering from the long-term emotional consequences of severe trauma. Now it looked like trauma leaves a trace in offspring even before they are born. © 2022 Scientific American

Keyword: Epigenetics; Stress
Link ID: 28378 - Posted: 06.25.2022

Smriti Mallapaty Live-cell imaging of the eye’s transparent cornea has revealed a surprising resident — specialized immune cells that circle the tissue, ready to attack pathogens. “We thought that the central cornea was devoid of any immune cells,” says Esen Akpek, a clinician-scientist who works on immunological diseases of the cornea at Johns Hopkins University in Baltimore, Maryland. The study, published in Cell Reports1 on 24 May, could help researchers to better understand diseases that affect the eye and to develop therapies that target infections on the eye’s surface, says Tanima Bose, an immunologist at the pharmaceutical company Novartis in Kundl, Austria. Immune response The cornea has a dampened response to infection, in part because aggressive immune cells could damage the clear layer of tissue and obstruct vision, says co-author Scott Mueller, an immunologist at the University of Melbourne, Australia. For this reason, the immune cells that mount a quick but crude response to an infection, such as dendritic cells and macrophages, largely reside in the outer sections of the cornea and emerge only when needed. But in almost every tissue in the body are long-lived immune cells, known as T cells, that swiftly attack pathogens they have previously encountered — a process called ‘immune memory’. Mueller and his colleagues wondered whether such cells lived in the cornea. Using a powerful multiphoton microscope for studying living tissue, the researchers examined the corneas of mice whose eyes had been infected with herpes simplex virus. They saw that cytotoxic T cells and T-helper cells — precursors for immune memory — had infiltrated the cornea and persisted for up to a month after the infection. Further investigations, including more intrusive microscopy techniques, revealed that the cytotoxic T cells had developed into long-lived memory cells that resided in the cornea. © 2022 Springer Nature Limited

Keyword: Vision; Neuroimmunology
Link ID: 28357 - Posted: 06.07.2022

Meghan Hoyer and Tim Meko When Vanderbilt University psychiatrist Jonathan Metzl learned that the perpetrator of the Uvalde, Tex., school massacre was a young man barely out of adolescence, it was hard not to think about the peculiarities of the maturing male brain. Salvador Rolando Ramos had just turned 18, eerily close in age to Nikolas Cruz, who had been 19 when he shot up a school in Parkland, Fla. And to Adam Lanza, 20, when he did the same in Newtown, Conn. To Seung-Hui Cho, 23, at Virginia Tech. And to Eric Harris, 18, and Dylan Klebold, 17, in Columbine, Colo. Teen and young adult males have long stood out from other subgroups for their impulsive behavior. They are far more reckless and prone to violence than their counterparts in other age groups, and their leading causes of death includes fights, accidents, driving too fast, or, as Metzl put it, “other impulsive kinds of acts.” “There’s a lot of research about how their brains are not fully developed in terms of regulation,” he said. Perhaps most significantly, studies show, the prefrontal cortex, which is critical to understanding the consequences of one’s actions and controlling impulses, does not fully develop until about age 25. In that context, Metzl said, a shooting “certainly feels like another kind of performance of young masculinity.” In coming weeks and months, investigators will dissect Ramos’s life to try to figure out what led him to that horrific moment at 11:40 a.m. Tuesday, May 24 when he opened fire on a classroom full of 9- and-10-year-olds at Robb Elementary School. Although clear answers are unlikely, the patterns that have emerged about mass shooters in the growing databases, school reports, medical notes and interview transcripts show a disturbing confluence between angry young men, easy access to weapons and reinforcement of violence by social media. © 1996-2022 The Washington Post

Keyword: Aggression; Hormones & Behavior
Link ID: 28352 - Posted: 06.04.2022

By Amber Dance Suppose a couple has two children, a boy and a girl. Chances are, they’ll both grow up with typical, healthy brains. But should either diverge from the usual route of brain development, or suffer mental health issues, their paths are likely to be different. The son’s differences might show up first. All else being equal, he’s four times more likely than his sister to be diagnosed with autism. Rates of other neurodevelopmental conditions and disabilities are also higher in boys. As he grows into a young man, his chances of developing schizophrenia will be two to three times higher than hers. When the siblings hit puberty, those relative risks will flip. The sister will be almost twice as likely to experience depression or an anxiety disorder. Much later in life, she’ll be at higher risk of developing Alzheimer’s disease. Those trends are not hard and fast rules, of course: Men can and do suffer from depression and Alzheimer’s; some girls develop autism; women aren’t immune to schizophrenia. Male and female brains are more alike than they are different. But scientists are learning that there’s more to these different risk profiles than, say, the pressures women face in a patriarchal society or the fact that women tend to live longer, giving diseases of aging time to develop. Subtle biological differences between male and female brains, and bodies, are important contributors. To explain these sex differences, there are some obvious places to look. The female’s two X chromosomes, to the male’s single copy, is one. Differing sex hormones — primarily testosterone in males and estrogen in females — is another. But a steadily growing body of research points to a less obvious influence: the cells and molecules of the immune system. © 2022 Annual Reviews

Keyword: Sexual Behavior; Neuroimmunology
Link ID: 28345 - Posted: 06.01.2022

Diana Kwon The brain is the body’s sovereign, and receives protection in keeping with its high status. Its cells are long-lived and shelter inside a fearsome fortification called the blood–brain barrier. For a long time, scientists thought that the brain was completely cut off from the chaos of the rest of the body — especially its eager defence system, a mass of immune cells that battle infections and whose actions could threaten a ruler caught in the crossfire. In the past decade, however, scientists have discovered that the job of protecting the brain isn’t as straightforward as they thought. They’ve learnt that its fortifications have gateways and gaps, and that its borders are bustling with active immune cells. A large body of evidence now shows that the brain and the immune system are tightly intertwined. Scientists already knew that the brain had its own resident immune cells, called microglia; recent discoveries are painting more-detailed pictures of their functions and revealing the characteristics of the other immune warriors housed in the regions around the brain. Some of these cells come from elsewhere in the body; others are produced locally, in the bone marrow of the skull. By studying these immune cells and mapping out how they interact with the brain, researchers are discovering that they play an important part in both healthy and diseased or damaged brains. Interest in the field has exploded: there were fewer than 2,000 papers per year on the subject in 2010, swelling to more than 10,000 per year in 2021, and researchers have made several major findings in the past few years. No longer do scientists consider the brain to be a special, sealed-off zone. “This whole idea of immune privilege is quite outdated now,” says Kiavash Movahedi, a neuroimmunologist at the Free University of Brussels (VUB). Although the brain is still seen as immunologically unique — its barriers prevent immune cells from coming and going at will — it’s clear that the brain and immune system constantly interact, he adds (see ‘The brain’s immune defences’). © 2022 Springer Nature Limited

Keyword: Neuroimmunology; Glia
Link ID: 28344 - Posted: 06.01.2022

By Lisa Sanders, M.D. “You have to take your husband to the hospital right now,” the doctor urged over the phone. “His kidneys aren’t working at all, and we need to find out why.” The woman looked at her 82-year-old spouse. He was so thin and pale. She thanked the doctor and called 911. For the past couple of months, every meal was a struggle. Swallowing food was strangely difficult. Liquids were even worse. Whatever he drank seemed to go down the wrong pipe, and he coughed and sputtered after almost every sip. It was terrifying. He saw an ear, nose and throat specialist, who scoped his mouth and esophagus. There wasn’t anything blocking the way. The doctor recommended that he get some therapy to help him strengthen the muscles he used to swallow, and until he did that, he should thicken his liquids to make drinking easier. The patient tried that once, but it was so disgusting he gave up on it. His wife was worried as she watched him eat and drink less and less. She could see that he was getting weaker every day. He had a stroke four months earlier, and since then his right foot dragged a little. But now she had to help him get out of his recliner. And he wasn’t able to drive — she had to make the 45-minute trip with him each day to his office. Finally, he agreed to see Dr. Richard Kaufman, their primary-care doctor. Kaufman was shocked by the man’s appearance, how the skin on his face hung in folds as if air had been let out of his cheeks. He’d lost nearly 40 pounds. He struggled to walk the few steps to the exam table. His right side, which was weakened by his stroke, was now matched by weakness on his left side. His stroke hadn’t done this. There was something else going on. Kaufman ordered some preliminary blood tests to try to see where the problem might lie. Those were the results that sent the couple to the emergency room. © 2022 The New York Times Company

Keyword: Neuroimmunology; Muscles
Link ID: 28339 - Posted: 05.28.2022

By Ernesto Londoño TIJUANA, Mexico — Plumes of incense swirled through the dimly lit living room as seven women took turns explaining what drove them to sign up for a weekend of psychedelic therapy at a villa in northern Mexico with sweeping ocean views. A former U.S. Marine said she hoped to connect with the spirit of her mother, who killed herself 11 years ago. An Army veteran said she had been sexually assaulted by a relative as a child. A handful of veterans said they had been sexually assaulted by fellow service members. The wife of a Navy bomb disposal expert choked up as she lamented that years of unrelenting combat missions had turned her husband into an absent, dysfunctional father. Kristine Bostwick, 38, a former Navy corpsman, said she hoped that putting her mind through ceremonies with mind-altering substances would help her make peace with the end of a turbulent marriage and perhaps ease the migraines that had become a daily torment. “I want to reset my brain from the bottom up,” she said during the introductory session of a recent three-day retreat, wiping away tears. “My kids deserve it. I deserve it.” A growing body of research into the therapeutic benefits of psychedelic therapy has generated enthusiasm among some psychiatrists and venture capitalists. Measures to decriminalize psychedelics, fund research into their healing potential and establish frameworks for their medicinal use have been passed with bipartisan support in city councils and state legislatures across the United States in recent years. Much of the expanding appeal of such treatments has been driven by veterans of America’s wars in Afghanistan and Iraq. Having turned to experimental therapies to treat post-traumatic stress disorder, traumatic brain injuries, addiction and depression, many former military members have become effusive advocates for a wider embrace of psychedelics. © 2022 The New York Times Company

Keyword: Stress; Drug Abuse
Link ID: 28338 - Posted: 05.25.2022

By Tess Joosse The mere sight of another person yawning causes many of us to open our mouths wide in mimicry. And we’re not alone—other social animals, such aschimpanzees and lions, can also catch so-called contagious yawns. It’s likely that all vertebrates yawn spontaneously to regulate inner body processes. Yawning probably arose with the evolution of jawed fishes 400 million or so years ago, says Andrew Gallup, an evolutionary biologist at State University of New York Polytechnic Institute who has spent years trying to figure out why we yawn. In a paper published this month in Animal Behavior, he reports some evidence for how contagious yawns might have evolved to keep us safe. Science chatted with Gallup about why yawning is ubiquitous—and useful. This interview has been edited for clarity and length. Q: First, let’s address a long-standing myth: Does yawning increase blood oxygen levels? A: No. Despite continued belief, research has explicitly tested that hypothesis and the results have concluded that breathing and yawning are controlled by different mechanisms. For example, there are really interesting cases of yawning in marine mammals, where the yawning occurs while the animal is submerged underwater and therefore not breathing. Q: So what does yawning actually do to the body? A: Yawning is a rather complex reflex. It’s triggered under a variety of contexts and neurophysiological changes. It primarily occurs during periods of state change, commonly following transitions of sleeping and waking. There’s research that also suggests that yawns are initiated alongside increases in cortical arousal, so yawns themselves may function to promote alertness. And there’s a growing body of research that suggests that yawning is triggered by rises in brain temperature. I’ve conducted a number of studies testing this in humans, nonhuman mammals, and even birds. © 2022 American Association for the Advancement of Science.

Keyword: Emotions; Evolution
Link ID: 28337 - Posted: 05.25.2022

By James Gorman Don’t judge a book by its cover. Don’t judge a dog by its breed. After conducting owner surveys for 18,385 dogs and sequencing the genomes of 2,155 dogs, a group of researchers reported a variety of findings in the journal Science on Thursday, including that for predicting some dog behaviors, breed is essentially useless, and for most, not very good. For instance, one of the clearest findings in the massive, multifaceted study is that breed has no discernible effect on a dog’s reactions to something it finds new or strange. This behavior is related to what the nonscientist might call aggression and would seem to cast doubt on breed stereotypes of aggressive dogs, like pit bulls. One thing pit bulls did score high on was human sociability, no surprise to anyone who has seen internet videos of lap-loving pit bulls. Labrador retriever ancestry, on the other hand, didn’t seem to have any significant correlation with human sociability. This is not to say that there are no differences among breeds, or that breed can’t predict some things. If you adopt a Border collie, said Elinor Karlsson of the Broad Institute and the University of Massachusetts Chan Medical School, an expert in dog genomics and an author of the report, the probability that it will be easier to train and interested in toys “is going to be higher than if you adopt a Great Pyrenees.” But for any given dog you just don’t know — on average, breed accounts for only about 9 percent of the variations in any given dog’s behavior. And no behaviors were restricted to any one breed, even howling, though the study found that behavior was more strongly associated with breeds like Siberian huskies than with other dogs. And yet, in what might seem paradoxical at first, the researchers also found that behavior patterns are strongly inherited. The behaviors they studied had a 25 percent heritability, a complex measure which indicates the influence of genes, but depends on the group of animals studied. But with enough dogs, heritability is a good measure of what’s inherited. In comparing whole genomes, they found several genes that clearly influence behavior, including one for how friendly dogs are. © 2022 The New York Times Company

Keyword: Genes & Behavior; Aggression
Link ID: 28309 - Posted: 04.30.2022