Chapter 15. Emotions, Aggression, and Stress

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By Joshua Rapp Learn Giraffes don’t fight much, says Jessica Granweiler, a master’s student at the University of Manchester in England who studies nature’s tallest mammals. When they do, look out. “Fighting is extremely rare because it’s extremely violent,” Ms. Granweiler said. When older adult males joust for territory or mating rights, their hornlike pairs of ossicones thrust with the force of their long necks and can cut into their opponents’ flesh, wounding and sometimes even killing a combatant. But some forms of giraffe dueling serve other purposes. In a study published last month in the journal Ethology, Ms. Granweiler and her colleagues reported some discoveries about sparring behavior that help giraffes establish social hierarchies. They showed that the animals didn’t take advantage of smaller members of their herds, but rather practiced their head butts with males of similar stature in ways that to a human might even appear fair or honorable. Such findings could aid in the conservation of the dwindling populations of the animals. Ms. Granweiler and her colleagues observed social behavior in giraffes at the small Mogalakwena River Reserve in South Africa from November 2016 to May 2017. They began to record the details of these fights — basically a who-fought-who, and how in the giraffe world. They were surprised to find that giraffes, like humans, can be righties or southpaws when it comes to sparring. Even the youngest animals showed a clear preference, although unlike humans it seemed they were evenly split between lefties and righties. The researchers also noticed that the younger males sparred more with each other, and nearly always chose opponents similar in size to themselves — there wasn’t a lot of bullying going on. A bar brawl effect went on as well, where one sparring match seemed to infect the crowd and prompt more fights around them. © 2021 The New York Times Company

Keyword: Aggression; Sexual Behavior
Link ID: 27997 - Posted: 09.18.2021

by Giorgia Guglielmi Severe infections during early childhood are linked to autism — at least in some boys, a new study in mice and people suggests. The findings were published today in Science Advances. Researchers analyzed the health records of millions of children in the United States and found that boys diagnosed with autism are more likely than non-autistic boys to have had an infection requiring medical attention between age 1 and a half and 4. The study also showed that provoking a strong immune response in newborn mice with only one copy of TSC2, a gene tied to autism, leads to social memory problems in adult male rodents. In people, mutations in TSC2 cause tuberous sclerosis, a condition characterized by non-cancerous tumors and skin growths. About half of all people with tuberous sclerosis also have autism. “If the TSC2 mutation was sufficient to cause autism, then everyone with that mutation would have autism — but they don’t,” says senior investigator Alcino Silva, director of the Integrative Center for Learning and Memory at the University of California, Los Angeles. A child’s chances of having autism rise with severe infections in the child or his mother, previous studies show, but not all children who contract serious infections go on to be diagnosed with autism. The new study is the first to examine the relationship between immune activation and a specific genetic variant tied to autism, Silva says. The findings suggest that genetics and severe infection represent a ‘two-hit’ scenario for autism. © 2021 Simons Foundation

Keyword: Autism; Development of the Brain
Link ID: 27996 - Posted: 09.18.2021

By Lisa Sanders, M.D. The young woman was awakened by the screams of her 39-year-old husband. “Please make it stop!” he shouted, leaping from the bed. “It hurts!” He paced back and forth across the room, arms crossed over his chest as if to protect himself. Two days earlier, he had inhaled a breath mint when his wife startled him. He felt it move slowly down his throat as he swallowed repeatedly. His chest had hurt ever since. But not like this. The man squirmed miserably throughout the short drive to the emergency room at Westerly Hospital, near the Rhode Island and Connecticut border. No position was comfortable. Everything hurt. Even breathing was hard. Although the doctors in the E.R. immediately determined that the young man wasn’t having a heart attack, it was clear something was very wrong. His blood pressure was so low that it was hard to measure. A normal blood pressure may be 120/80. On arrival, his was 63/32. With a pressure this low, blood couldn’t get everywhere it was needed — a condition known as shock. His lips, hands and feet had a dusky hue from this lack of well-​oxygenated blood. He was given intravenous fluids to bring up his pressure, and when that didn’t work, he was started on medications for it. Three hours later, he was on two of these medicines and his fourth liter of fluid. Despite that, his pressure remained in the 70s. He had to be put on a breathing machine to help him keep up with his body’s demand for more oxygen. The most common cause of shock is infection. But this man, as sick as he was, had no signs of infection. The medical team started him on antibiotics anyway. Could the painful mint have torn his esophagus? Up to 50 percent of patients with that injury will die. A CT scan showed no evidence of perforation or of fluid in his chest. What else could this be? There was no sign of a clot keeping blood from entering the lungs, another cause of deadly low blood pressure. An ultrasound of the heart showed that he had some fluid in the sac called the pericardium, which contains and protects the heart, but not enough to interfere with how well it was beating. He was tested for Covid and for recreational drugs — both negative. © 2021 The New York Times Company

Keyword: Hormones & Behavior; Neuroimmunology
Link ID: 27981 - Posted: 09.08.2021

By Cara Giaimo Giraffes seem above it all. They float over the savanna like two-story ascetics, peering down at the fray from behind those long lashes. For decades, many biologists thought giraffes extended this treatment to their peers as well, with one popular wildlife guide calling them “aloof” and capable of only “the most casual” associations. Sign up for Science Times Get stories that capture the wonders of nature, the cosmos and the human body. Get it sent to your inbox. But more recently, as experts have paid closer attention to these lanky icons, a different social picture has begun to emerge. Female giraffes are now known to enjoy yearslong bonds. They have lunch buddies, stand guard over dead calves and stay close with their mothers and grandmothers. Females even form shared day care-like arrangements, called crèches, in which they take turns babysitting and feeding each others young. Observations like these have reached a critical mass, said Zoe Muller, a wildlife biologist who completed her Ph.D. at the University of Bristol in England. She and Stephen Harris, also at Bristol, recently reviewed hundreds of giraffe studies to look for broader patterns. Their analysis, published on Tuesday in the journal Mammal Review, suggests that giraffes are not loners, but socially complex creatures, akin to elephants or chimpanzees. They’re just a little more subtle about it. Dr. Muller’s sense of giraffes as secret socialites began in 2005, when she was researching her master’s thesis in Laikipia, Kenya. There to collect data on antelopes, she found herself drawn to the ganglier ungulates. “They are so weird to look at,” she said. “If somebody described them to you, you wouldn’t believe they even really existed.” After noticing that the same giraffes tended to spend time together — they looked “like teenagers hanging out,” she said — Dr. Muller started to read up on their lifestyles. “I was really surprised to see that all the scientific books said that they were completely non-sociable,” she said. “I thought, ‘Well, hang on. That’s not what I see at all.’” © 2021 The New York Times Company

Keyword: Evolution; Emotions
Link ID: 27945 - Posted: 08.11.2021

Max G. Levy Agony is contagious. If you drop a thick textbook on your toes, circuits in your brain’s pain center come alive. If you pick it up and accidentally drop it on my toes, hurting me, an overlapping neural neighborhood will light up in your brain again. “There's a physiological mechanism for emotional contagion of negative responses like stress and pain and fear,” says Inbal Ben-Ami Bartal, a neuroscientist at Tel-Aviv University in Israel. That's empathy. Researchers debate to this day whether empathy is a uniquely human ability. But more scientists are finding evidence suggesting it exists widely, particularly in social mammals like rats. For the past decade, Bartal has studied whether—and why—lab rodents might act on that commiseration to help pals in need. Picture two rats in a cage. One roams freely, while the other is constrained in a vented plexiglass tunnel with a small door that only opens from the outside. Bartal, along with teams at UC Berkeley and the University of Chicago, has shown that the free rat may feel their trapped fellow’s distress and learn to open the door. This empathic pull is so strong that rats will rescue their roommates instead of feasting on piles of chocolate chips. (Disclosure: I have three pet rats. My sources confirm that chocolate chips are borderline irresistible.) But there's been a catch: Bartal’s experiments over the years have shown that rats only help others they perceive as members of their social group—specific pals or entire genetic strains they recognize. So does this mean they can't empathize with strangers? In new results appearing in the journal eLife in July, Bartal and her adviser from Berkeley, Daniela Kaufer, uncovered a surprise. Rats do show the neural signatures of empathy for trapped strangers, but that alone isn’t enough to make them help. While seeing a trapped stranger lights up parts of the brain associated with empathy, only seeing a familiar rat or breed elicits a rush of activity in the brain’s so-called reward center, the nucleus accumbens—so only those rats get rescued. © 2021 Condé Nast

Keyword: Emotions; Evolution
Link ID: 27943 - Posted: 08.11.2021

By Jane E. Brody No one with debilitating symptoms likes to be told “it’s all in your head.” Yet, this is often what distressed patients with irritable bowel syndrome hear, implicitly or explicitly, when a medical work-up reveals no apparent explanation for their repeated bouts of abdominal pain, bloating, diarrhea or constipation. In fact, irritable bowel syndrome, or I.B.S., is a real problem causing real symptoms, no matter how hard its sufferers may wish it gone. But unlike an infection or tumor, I.B.S. is what medicine calls a functional disorder: a condition with no identifiable cause. Patients have no visible signs of damage or disease in their digestive tracts. Rather, the prevailing theory holds that overly sensitive nerves in the patient’s gastrointestinal tract send distress signals to the brain that result in pain and malfunction. However, as medical science progresses, experts are beginning to find physical explanations for disorders that previously had no known biological cause. For example, conditions like epilepsy, Alzheimer’s disease and migraine were once considered functional disorders, but are now known to have measurable physical or biochemical underpinnings. And recent research has revealed at least one likely explanation for the symptoms of I.B.S.: an infection in the digestive tract that triggers a localized allergic reaction in the gut. As Dr. Marc E. Rothenberg wrote in The New England Journal of Medicine in June, “Patients with I.B.S. often report that their symptoms started at the time of a gastrointestinal infection.” Dr. Rothenberg, who is the director of the division of allergy and immunology at Cincinnati Children’s Hospital Medical Center, explained in an interview that the infection can temporarily disrupt the layer of cells that normally lines the bowel. These cells form a barrier that prevents allergy-inducing proteins in foods from being absorbed. When that barrier is penetrated, people can become intolerant to foods that previously caused them no issue. Sign up for the Well Newsletter Get the best of Well, with the latest on health, fitness and nutrition. Get it sent to your inbox. © 2021 The New York Times Company

Keyword: Stress
Link ID: 27935 - Posted: 08.07.2021

Jason Ulrich and David M. Holtzman In 1907 German psychiatrist Alois Alzheimer published a case report of an unusual illness affecting the cerebral cortex. A 51-year-old woman living in an asylum in Frankfurt am Main exhibited symptoms that are all too familiar to the millions of families affected by what is now known as Alzheimer’s disease. There was memory loss, confusion and disorientation. After the patient died, Alzheimer examined her brain and made a few key observations. First, it was smaller than average, or atrophic, with a corresponding loss of neurons. Next, there were tangles of protein fibers within neurons and deposits of a different protein outside brain cells. For the next 100 years, these two pathological proteins—known as tau and amyloid—were the focus of research into the causes of the disease. But there was an additional, often forgotten clue that Alzheimer noted in the autopsy. Under the microscope lens, he saw clear changes in the structural makeup of certain nonneuronal cells. Called glia, they constitute roughly half of the brain’s cells. After being studied by only a small number of scientists since Alzheimer’s discovery, glia have now entered the spotlight. One type, called microglia, is the main kind of immune cell in the brain and may influence the progression of the disease in different ways during both early and later stages. Microglia might also explain the complex relation between amyloid and tau, the aberrant proteins that lead to neuron degeneration and memory loss. © 2021 Scientific American

Keyword: Alzheimers; Neuroimmunology
Link ID: 27927 - Posted: 07.28.2021

Nidhi Subbaraman Maeve Wallace has studied maternal health in the United States for more than a decade, and a grim statistic haunts her. Five years ago, she published a study showing that being pregnant or recently having had a baby nearly doubles a woman’s risk of being killed1. More than half of the homicides she tracked, using data from 37 states, were perpetrated with a gun. In March 2020, she saw something she hadn’t seen before: a funding opportunity from the US National Institutes of Health (NIH) to study deaths and injuries from gun violence. She had mentioned firearms in her studies before. But knowing that the topic is politically fraught, she often tucked related terms and findings deep within her papers and proposals. This time, she says, she felt emboldened to focus on guns specifically, and to ask whether policies that restrict firearms for people convicted of domestic violence would reduce the death rate for new and expecting mothers. Male partners are the killers in nearly half of homicides involving women in the United States. “This call for proposals really motivated me to ask the research questions that I may not have otherwise asked,” says Wallace, an epidemiologist at Tulane University in New Orleans, Louisiana. Wallace’s group is one of several dozen funded by a new pool of federal money for gun-violence research in the United States, which has more firearm-related deaths than any other wealthy nation. Although other countries fund research on guns, it is often in the context of trafficking and armed conflict. US federal funding of gun-violence research has not reflected the death toll, researchers say. © 2021 Springer Nature Limited

Keyword: Aggression
Link ID: 27922 - Posted: 07.24.2021

Amanda Heidt Takotsubo syndrome, also known as broken heart syndrome, is a rare, reversible condition with symptoms mimicking a mild heart attack. A disease that disproportionately affects women, TTS is triggered by stressful events such as bankruptcy, the death of a loved one, or divorce, and results in a weakening of the heart’s left ventricle such that it becomes temporarily misshapen. Previous work has shown that TTS patients have elevated activity in their amygdala, a brain region involved in stress response. What has never been clear, however, is whether “this activity in the brain happens as a result of the syndrome or whether it began many years before,” says Shady Abohashem, a nuclear cardiologist at Harvard Medical School. Abohashem and his colleagues retrospectively analyzed full-body PET/CT scans from 104 patients, most of whom had cancer and 41 of whom had developed TTS since first being scanned, and 63 individually matched controls. The team calculated ratios of the activity in each person’s amygdala to that of two brain regions that attenuate the stress response, the temporal lobe and the prefrontal cortex. Higher amygdala activity was associated with an increased risk for TTS, and among those with the condition, patients with higher ratios had developed TTS roughly two years earlier following the imaging than those with lower ratios. “We can now show that this syndrome happens as a result of chronic stress over years that makes you vulnerable to developing the syndrome more easily and sooner than [less stressed] people,” Abohashem says. © 1986–2021 The Scientist.

Keyword: Stress
Link ID: 27920 - Posted: 07.24.2021

By Elizabeth Pennisi In hyenas as well as humans, it pays to be born to high-ranking parents. A new study reveals how power is passed down in these matriarchal mammals: Elite hyena cubs cultivate their mom’s friends, who help keep them fed and protected throughout their lives. The work drives home the role moms and dads play in shaping the social world of their children, says Josh Firth, a social networks researcher at the University of Oxford who was not involved with the study. “We tend to think about who we are connected to as a product of our doing, but it’s a product of our parents as well.” Chimpanzees, hyenas, and other social animals live in hierarchical societies. Those at the top eat first, and are typically surrounded by a gang that protects them from other members of their species that try to challenge their status. High rank tends to be inherited, but it’s been unclear how subsequent generations end up with the same type of ruling clan their parents do. Do they recruit their own powerful allies, or inherit them? Erol Akçay, a theoretical biologist at the University of Pennsylvania, and behavioral ecologist Amiyaal Ilany, now at Bar-Ilan University, decided to analyze the work of Kay Holekamp. A behavioral ecologist at Michigan State University, Holekamp’s team had been following the lives of a clan of spotted hyenas (Crocuta crocuta) in Kenya for almost 30 years. Day after day, the researchers have recorded the activity of the hyenas, including their interactions with and proximity to other hyenas, to understand the species’ behavior and ecology. They have also kept track of the pedigrees and social status of each female and its offspring. © 2021 American Association for the Advancement of Science.

Keyword: Aggression; Sexual Behavior
Link ID: 27912 - Posted: 07.17.2021

By Emily Anthes Johnson & Johnson’s beleaguered Covid-19 vaccine may be associated with a small increased risk of Guillain–Barré syndrome, a rare but potentially serious neurological condition, federal officials said on Monday. The Food and Drug Administration has added a warning about the potential side effect to its fact sheets about the vaccine. The risk appears to be very small. So far, there have been 100 reports of the syndrome in people who had received the Johnson & Johnson vaccine. Nearly 13 million doses of the vaccine have been administered in the United States. Here are answers to some common questions about the syndrome and its connection to vaccination. What is Guillain-Barré syndrome? Guillain-Barré is a rare condition in which the body’s immune system attacks nerve cells. It can cause muscle weakness and paralysis. Although the symptoms often pass within weeks, in some cases, the condition can cause permanent nerve damage. In the United States, there are typically 3,000 to 6,000 cases of the syndrome per year, according to the Centers for Disease Control and Prevention. It is most common in adults over 50. The precise cause of the syndrome is unknown, but in many cases the condition follows another illness or infection, such as the flu. It has also been reported in people with Covid-19. This is not the first vaccine that has been linked to Guillain-Barré, although the risk appears to be tiny. A large swine flu vaccination campaign in 1976 led to a small uptick in the incidence of syndrome; the vaccine caused roughly one extra case of Guillain-Barré for every 100,000 people vaccinated. The seasonal flu shot is associated with roughly one to two additional cases for every million vaccines administered. © 2021 The New York Times Company

Keyword: Movement Disorders; Neuroimmunology
Link ID: 27909 - Posted: 07.14.2021

Linda Geddes Science correspondent Fibromyalgia – a poorly understood condition that causes widespread pain throughout the body and extreme tiredness – may be caused by be an autoimmune response that increases the activity of pain-sensing nerves throughout the body. The findings, published in the Journal of Clinical Investigation, challenge the widely held view that the condition originates in the brain, and could pave the way for more effective treatments for the millions of people affected. They could also have implications for patients suffering from myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and “long Covid”. “These different syndromes are symptomatically very similar, so I think it could be very relevant to both of these conditions,” said Dr David Andersson from the Institute of Psychiatry, Psychology and Neuroscience at King’s College London, who led the new study. Fibromyalgia affects at least 1 in 40 people worldwide, although some estimates suggest nearly 1 in 20 people may be affected to some degree. It is characterised by widespread pain and crippling fatigue – often referred to as “fibro fog” – and usually develops between the ages of 25 and 55, although children can also get it. Similar to many autoimmune conditions, the vast majority of those affected (80% are women). Current treatment tends to focus on gentle aerobic exercise, as well as drug and psychological therapies designed to manage pain. However, these have proven ineffective in most patients and have left behind an enormous unmet clinical need, said Andersson. “The widespread paradigm at the moment is that this is a disease that emanates from the brain, and I think our findings suggest that that’s not the case,” he said. © 2021 Guardian News & Media Limited

Keyword: Neuroimmunology; Depression
Link ID: 27888 - Posted: 07.03.2021

By Katherine Ellison Remember the line from that old folk song? If living were a thing that money could buy You know the rich would live and the poor would die. Sadly, there’s little “if” about it. On average, the poor live less healthy lives and are more than three times as likely to die prematurely as the rich. That’s true for many well-documented reasons, including less healthy diets with too much processed food, polluted neighborhoods and a lot more toxic stress. In recent years, however, researchers have added one more factor to this mix: It turns out that the poor, as well as socially disadvantaged racial minorities, sleep much less well on average than the rich, which can take a major toll on their physical and mental health. “We used to think that sleep problems were limited to Type A professionals, and they certainly aren’t immune, but low-income individuals and racial minorities are actually at greatest risk,” says Wendy Troxel, a senior behavioral and social scientist at the RAND Corporation, who coauthored an analysis of socioeconomic disparities in sleep and health in the 2020 Annual Review of Public Health. Inadequate sleep among low-income adults and racial minorities contributes to higher rates of illnesses, including cardiovascular disease and dementia, both of which are more common among these groups, Troxel and her coauthors point out. One study they cite attributes more than half of the differences in health outcomes between whites and Blacks, for example, to differences in quantity or quality of sleep. You might think of this as the great sleep divide. © 2021 Annual Reviews, Inc

Keyword: Sleep; Stress
Link ID: 27881 - Posted: 06.29.2021

Kareem Clark With COVID-19 vaccines working and restrictions lifting across the country, it’s finally time for those now vaccinated who’ve been hunkered down at home to ditch the sweatpants and reemerge from their Netflix caves. But your brain may not be so eager to dive back into your former social life. Social distancing measures proved essential for slowing COVID-19’s spread worldwide – preventing upward of an estimated 500 million cases. But, while necessary, 15 months away from each other has taken a toll on people’s mental health. In a national survey last fall, 36% of adults in the U.S. – including 61% of young adults – reported feeling “serious loneliness” during the pandemic. Statistics like these suggest people would be itching to hit the social scene. But if the idea of making small talk at a crowded happy hour sounds terrifying to you, you’re not alone. Nearly half of Americans reported feeling uneasy about returning to in-person interaction regardless of vaccination status. Transparent, research-based, written by experts – and always free. So how can people be so lonely yet so nervous about refilling their social calendars? Well, the brain is remarkably adaptable. And while we can’t know exactly what our brains have gone through over the last year, neuroscientists like me have some insight into how social isolation and resocialization affect the brain.

Keyword: Stress
Link ID: 27879 - Posted: 06.29.2021

By Juan Siliezar Harvard Staff Writer When Erin Hecht was earning her Ph.D. in neuroscience more than a decade ago, she watched a nature special on the Russian farm-fox experiment, one of the best-known studies on animal domestication. The focus of that ongoing research, which began in 1958, is to try to understand the process by which wild wolves became domesticated dogs. Scientists have been selectively breeding two strains of silver fox — an animal closely related to dogs — to exhibit certain behaviors. One is bred to be tame and display dog-like behaviors with people, such as licking and tail-wagging, and the other to react with defensive aggression when faced with human contact. A third strain acts as the control and isn’t bred for any specific behaviors. Hecht, who’s now an assistant professor in the Harvard Department of Human Evolutionary Biology, was fascinated by the experiment, which has helped scientists closely analyze the effects of domestication on genetics and behavior. But she also thought something fundamental was missing. What she didn’t know was that filling that knowledge gap could potentially force reconsideration of what was known about the connection between evolutionary changes in behavior and those in the brain. “In that TV show, there was nothing about the brain,” Hecht said. “I thought it was kind of crazy that there’s this perfect opportunity to be studying how changes in brain anatomy are related to changes in the genome and changes in behavior, but nobody was really doing it yet.”

Keyword: Aggression; Evolution
Link ID: 27872 - Posted: 06.23.2021

By Christa Lesté-Lasserre In the animal kingdom, killer whales are social stars: They travel in extended, varied family groups, care for grandchildren after menopause, and even imitate human speech. Now, marine biologists are adding one more behavior to the list: forming fast friendships. A new study suggests the whales rival chimpanzees, macaques, and even humans when it comes to the kinds of “social touching” that indicates strong bonds. The study marks “a very important contribution to the field” of social behavior in dolphins and whales, says José Zamorano-Abramson, a comparative psychologist at the Complutense University of Madrid who wasn’t involved in the work. “These new images show lots of touching of many different types, probably related to different kinds of emotions, much like the complex social dynamics we see in great apes.” Audio and video recordings have shown how some marine mammals maintain social structures—including male dolphins that learn the “names” of close allies. But there is little footage of wild killer whales—which hunt and play in open water. Although the whales only swim at about 6 kilometers per hour, it’s hard to fully observe them from boats, and they might not act naturally near humans, Zamorano-Abramson says. That’s where drone technology came swooping in. Michael Weiss, a behavioral ecologist at the Center for Whale Research in Friday Harbor, Washington, teamed up with colleagues to launch unmanned drones from their 6.5-meter motorboat and from the shores of the northern Pacific Ocean, flying them 30 to 120 meters above a pod of 22 southern resident killer whales. That was high enough to respect federal aviation requirements—and not bother the whales. They logged 10 hours of footage over a 10-day period, marking the first time drones have been used to study friendly physical contacts in any cetacean. © 2021 American Association for the Advancement of Science.

Keyword: Evolution; Stress
Link ID: 27864 - Posted: 06.19.2021

By Deborah Schoch Marcel Kuttab first sensed something was awry while brushing her teeth a year ago, several months after recovering from Covid-19. Her toothbrush tasted dirty, so she threw it out and got a new one. Then she realized the toothpaste was at fault. Onions and garlic and meat tasted putrid, and coffee smelled like gasoline — all symptoms of the once little-known condition called parosmia that distorts the senses of smell and taste. Dr. Kuttab, 28, who has a pharmacy doctoral degree and works for a drug company in Massachusetts, experimented to figure out what foods she could tolerate. “You can spend a lot of money in grocery stores and land up not using any of it,” she said. The pandemic has put a spotlight on parosmia, spurring research and a host of articles in medical journals. Membership has swelled in existing support groups, and new ones have sprouted. A fast-growing British-based Facebook parosmia group has more than 14,000 members. And parosmia-related ventures are gaining followers, from podcasts to smell training kits. Yet a key question remains unanswered: How long does Covid-linked parosmia last? Scientists have no firm timelines. Of five patients interviewed for this article, all of whom first developed parosmia symptoms in late spring and early summer of last year, none has fully regained normal smell and taste. Brooke Viegut, whose parosmia began in May 2020, worked for an entertainment firm in New York City before theaters were shuttered. She believes she caught Covid in March during a quick business trip to London, and, like many other patients, she lost her sense of smell. Before she regained it completely, parosmia set in, and she could not tolerate garlic, onions or meat. Even broccoli, she said at one point earlier this year, had a chemical smell. She still can’t stomach some foods, but she is growing more optimistic. “A lot of fruits taste more like fruit now instead of soap,” she said. And she recently took a trip without getting seriously nauseous. “So, I’d say that’s progress.” © 2021 The New York Times Company

Keyword: Chemical Senses (Smell & Taste); Neuroimmunology
Link ID: 27857 - Posted: 06.16.2021

By Virginia Hughes Late one evening last March, just before the coronavirus pandemic shut down the country, Mingzheng Wu, a graduate student at Northwestern University, plopped two male mice into a cage and watched as they explored their modest new digs: sniffing, digging, fighting a little. Sign up for Science Times: Get stories that capture the wonders of nature, the cosmos and the human body. With a few clicks on a nearby computer, Mr. Wu then switched on a blue light implanted in the front of each animal’s brain. That light activated a tiny piece of cortex, spurring neurons there to fire. Mr. Wu zapped the two mice at the same time and at the same rapid frequency — putting that portion of their brains quite literally in sync. Within a minute or two, any animus between the two creatures seemed to disappear, and they clung to each other like long-lost friends. “After a few minutes, we saw that those animals actually stayed together, and one animal was grooming the other,” said Mr. Wu, who works in the neurobiology lab of Yevgenia Kozorovitskiy. Mr. Wu and his colleagues then repeated the experiment, but zapped each animal’s cortex at frequencies different from the other’s. This time, the mice displayed far less of an urge to bond. The experiment, published this month in Nature Neuroscience, was made possible thanks to an impressive new wireless technology that allows scientists to observe — and manipulate — the brains of multiple animals as they interact with one another. “The fact that you can implant these miniaturized bits of hardware and turn neurons on and off by light, it’s just mind-blowingly cool,” said Thalia Wheatley, a social neuroscientist at Dartmouth College who was not involved in the work. © 2021 The New York Times Company

Keyword: Aggression; Sexual Behavior
Link ID: 27832 - Posted: 05.27.2021

Elena Renken A hundred years ago, the Japanese scientist Y. Shirai published a mysterious finding: When Shirai transplanted tumor tissue into a mouse’s body, the tissue was destroyed by its immune system. But when tumors were grafted in various places in the mouse’s brain, they grew. Tumors seemed to be able to safely hide in the brain, escaping the immune system’s notice. Similar results soon piled up, and scientific consensus accepted the brain as having “immune privilege” — a kind of separation from the immune system. This notion made some sense. Immune cells, in the course of fighting infections, can damage or destroy healthy tissue. Protecting neurons from this damage is more crucial than protecting cells like those in the liver or skin, because neurons typically can’t regenerate. “If they die, they die,” said Justin Rustenhoven, an immunologist at Washington University in St. Louis. “We have a very poor ability to replace them.” In the last couple of decades, though, the idea of immune privilege has withered in the face of mounting evidence that the brain and the immune system do interact. Researchers have tracked immune cells crossing from the bloodstream into the nervous system in animals with brain disease, for instance, and they’ve observed cognitive deficits in mice that lack certain immune cells. Now, Rustenhoven and collaborators have identified how evolution achieves a balancing act, limiting the dangers of immune responses in the central nervous system while still providing protection from disease. The researchers reported recently in the journal Cell that the immune system operates from a distance to constantly inspect the brain for signs of trouble. Immune cells, rather than making themselves at home throughout the brain itself, patrol the sidelines until they detect a threat. All Rights Reserved © 2021

Keyword: Neuroimmunology
Link ID: 27799 - Posted: 05.01.2021

David Cox When John Abraham began to lose his mind in late 2019, his family immediately feared the worst. Abraham had enjoyed robust health throughout retirement, but now at 80 he suddenly found himself struggling to finish sentences. “I would be talking to people, and all of a sudden the final word wouldn’t come to mind,” he remembers. “I assumed this was simply a feature of ageing, and I was finding ways of getting around it.” But within weeks, further erratic behaviours started to develop. Abraham’s family recall him often falling asleep mid-conversation, he would sometimes shout out bizarre comments in public, and during the night he would wake up every 15 minutes, sometimes hallucinating. Patients can go from being in a nursing home, unable to communicate, to returning to work To his son Steve, the diagnosis seemed inevitable, one which all families dread. “I was convinced my dad had dementia,” he says. “What I couldn’t believe was the speed at which it was all happening. It was like dementia on steroids.” Dementia is not just one disease – it has more than 200 different subtypes. Over the past decade neurologists have become increasingly interested in one particular subtype, known as autoimmune dementia. In this condition, the symptoms of memory loss and confusion are the result of brain inflammation caused by rogue antibodies – known as autoantibodies – binding to the neuronal tissue, rather than an underlying neurodegenerative disease. Crucially this means that unlike almost all other forms of dementia, in some cases it can be cured, andspecialist neurologists have become increasingly adept at both spotting and treating it. © 2021 Guardian News & Media Limited

Keyword: Alzheimers; Neuroimmunology
Link ID: 27780 - Posted: 04.21.2021