Chapter 8. Hormones and Sex

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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 Marlene Cimons J. William Langston, who has been studying and treating Parkinson’s disease for nearly 40 years, always has found it striking that so many more men than women show up in his clinic. His observation is not anecdotal. It is grounded in science and shared by many physicians: Men are roughly 1.5 times more likely than women to develop Parkinson’s, a progressive disorder of the nervous system that impairs movement and can erode mental acuity. “It’s a big difference that is quite real,” says Langston, clinical professor of neurology, neuroscience and of pathology at the Stanford University School of Medicine and associate director of the Stanford Udall Center. “It’s pretty dramatic. I think anyone who sees a lot of Parkinson’s will tell you that.” While the disproportionate impact is clear, the reasons for it are not. “It’s a great mystery,” Langston says. Researchers still don’t know what it is that makes men more susceptible to Parkinson’s, or what it is about women that may protect them — or both. But they are trying to find out. “We in the research community have been working for decades to sort this out, but the answers are still elusive,” says Caroline Tanner, a neurology professor in the Weill Institute for Neurosciences at the University of California at San Francisco. “Nevertheless, it’s important to keep at it. We need to understand the mechanisms that underlie the specific differences between men and women so we can apply them to trying to prevent Parkinson’s.” Parkinson’s results from the death of key neurons in the substantia nigra region of the brain that produce the chemical messenger dopamine. Over time, the loss of these nerve cells disrupts movement, diminishes cognition, and can cause other symptoms, such as slurred speech and depression. © 1996-2021 The Washington Post

Keyword: Parkinsons; Sexual Behavior
Link ID: 27892 - Posted: 07.06.2021

By Gina Kolata Obesity has stalked Marleen Greenleaf, 58, all of her life. Like most people with obesity, she tried diet after diet. But the weight always came back. With that, she has suffered a lifetime of scorn and stigma. Jeering comments from strangers when she walked down the street. Family members who told her, when she trained for a half-marathon, “I don’t think it’s good for you.” Then, in 2018, Ms. Greenleaf, an administrator at a charter school in Washington, D.C., participated in a clinical trial for semaglutide, which is a new type of obesity drug, known as incretins. Over the course of the 68-week study, Ms. Greenleaf slowly lost 40 pounds. Until then, she had always believed that she could control her weight if she really tried. “I thought I just needed more motivation,” she said. But when she took semaglutide, she said that “immediately, the urge to eat just dissipated.” Incretins appear to elicit significant weight loss in most patients, enough to make a real medical and aesthetic difference. But experts hope that the drugs also do something else: change how society feels about people with obesity, and how people with obesity feel about themselves. If these new drugs allow obesity to be treated like a chronic disease — with medications that must be taken for a lifetime — the thought is that doctors, patients and the public might understand that obesity is truly a medical condition. © 2021 The New York Times Company

Keyword: Obesity; Hormones & Behavior
Link ID: 27821 - Posted: 05.15.2021

Rebecca Brooker & Tristin Nyman Even before the pandemic, there was plenty for expectant mothers to worry about. Pregnant women must withstand a barrage of arguably well-intentioned, but often hyperbolic, warnings about their health and what’s to come, including concerns about everything from what to eat, to what to wear, to how to feel. Health professionals know that mothers-to-be experience predictable increases in anxiety levels before infants are born. Maternal mental health has been steadily deteriorating in the U.S., particularly among poor and minority women. The calls to “be afraid, be very afraid” are, of course, countered by the equally strong cautions for pregnant women to not worry too much, lest it lead to long-term negative outcomes for them and their infants. Such warnings are not entirely off base. Maternal stress hormones cross the placenta and affect the vulnerable fetus. Fetal exposure to the stress hormone cortisol has been linked to an array of negative outcomes, including miscarriage and preterm birth, and irritable temperament for the child and increased risk of emotional problems during childhood. One thing researchers know is that anxious mothers tend to have anxious children. This common, albeit not prescriptive, phenomenon is likely due to numerous factors, both pre- and postpartum. In our laboratory, we focus on what happens when women start their pregnancies already worried or anxious and what clues we can uncover about how to help them and their children. Our research suggests that worry during pregnancy can have long-term impacts on how mothers’ brains communicate – but also that there might be some simple steps that can help rein in the effects. © 2010–2021, The Conversation US, Inc.

Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 27820 - Posted: 05.15.2021

By Lisa Sanders, M.D. “I can’t move my legs,” the 26-year-old man told his younger brother, who towered above him as he lay sprawled on the floor. He’d been on his computer for hours, he explained, and when he tried to stand up, he couldn’t. His legs looked normal, felt normal, yet they wouldn’t move. At first, he figured his legs must have fallen asleep. He pulled himself up, leaning on his desk, and slowly straightened until he was standing. He could feel the weight on his feet and knees. He let go of the desk and commanded his legs to move. Instead, they buckled, and he landed on the floor with a thud. His brother awkwardly pulled him onto the bed. Then they waited. Surely this weird paralysis would disappear just as suddenly as it came. An hour passed, then two. I’m calling an ambulance, the younger brother announced finally. Reluctantly, the elder agreed. He was embarrassed to be this helpless but worried enough to want help. When the E.M.T.s arrived, they were as confused as the brothers. The medics asked what the young man had been up to. Nothing bad, he assured them. For the past few weeks he had been getting back into shape. He changed his diet, cut out the junk and was drinking a protein concoction that was supposed to help him build muscle. And he was working out hard every day. He’d lost more than 20 pounds, he added proudly. © 2021 The New York Times Company

Keyword: Movement Disorders; Hormones & Behavior
Link ID: 27813 - Posted: 05.12.2021

by Jessica Jiménez, Mark Zylka Mice and rats typically give birth to 6 to 12 animals per litter. Some scientists treat this as a benefit, because a large number of animals can be produced with a small number of matings. In reality, though, this is of no benefit at all, especially when you consider a fact that is well known in the toxicology field: Animals within a litter are more similar to one another than animals between litters. Herein lies what is known as the ‘litter effect.’ Anyone who uses multiple animals from a small number of litters to increase sample size is making a serious mistake. The similarities within individual litters will heavily skew the results. Our goal in writing this article, and an accompanying peer-reviewed paper on this topic, is to raise awareness about the litter effect and to encourage researchers who study neurodevelopmental conditions to control for it in future work. Like many scientists who use rodents to study autism and related conditions, we were oblivious to the litter effect and its impact on research. However, we now recognize that it is essential to control for the litter effect whenever a rodent autism model is studied, be it a mouse with a gene mutation or an environmental exposure. It is essential because the litter effect can lead to erroneous conclusions that negatively influence the rigor and reproducibility of scientific research. Indeed, false positives, or the incorrect identification of a significant effect, increase as fewer litters are sampled. Conversely, litter-to-litter variation adds ‘noise’ to the data that can mask true treatment or genetic effects. This is concerning because most phenotypes associated with rodent models of autism are remarkably small, and they are often difficult to reproduce between labs. © 2021 Simons Foundation

Keyword: Development of the Brain; Sexual Behavior
Link ID: 27789 - Posted: 04.28.2021

Lise Eliot Everyone knows the difference between male and female brains. One is chatty and a little nervous, but never forgets and takes good care of others. The other is calmer, albeit more impulsive, but can tune out gossip to get the job done. These are stereotypes, of course, but they hold surprising sway over the way actual brain science is designed and interpreted. Since the dawn of MRI, neuroscientists have worked ceaselessly to find differences between men’s and women’s brains. This research attracts lots of attention because it’s just so easy to try to link any particular brain finding to some gender difference in behavior. But as a neuroscientist long experienced in the field, I recently completed a painstaking analysis of 30 years of research on human brain sex differences. And what I found, with the help of excellent collaborators, is that virtually none of these claims has proven reliable. Except for the simple difference in size, there are no meaningful differences between men’s and women’s brain structure or activity that hold up across diverse populations. Nor do any of the alleged brain differences actually explain the familiar but modest differences in personality and abilities between men and women. © 2010–2021, The Conversation US, Inc.

Keyword: Sexual Behavior; Brain imaging
Link ID: 27784 - Posted: 04.24.2021

By Emily Anthes Male tanagers are meant to be noticed. Many species of the small, tropical bird sport deep black feathers and splashes of eye-catching color — electric yellows, traffic-cone oranges and nearly neon scarlets. To achieve this flashiness, the birds must spend time and energy foraging for, and metabolizing, plants that contain special color pigments, which make their way into the feathers. A vibrantly colored male is thus sending an “honest signal,” many scientists have long theorized: He is alerting nearby females that he has a good diet, is in good health and would make a worthy mate. But some birds may be guilty of false advertising, a new study suggests. Male tanagers have microstructures in their feathers that enhance their colors, researchers reported Wednesday in the journal Scientific Reports. These microstructures, like evolution’s own Instagram filters, may make the males seem as if they are more attractive than they truly are. “Many male birds are colorful not just because they’re honestly signaling their quality, but because they’re trying to get chosen,” said Dakota McCoy, a doctoral student at Harvard University who conducted the research as part of her dissertation. “This is basically experimental evidence that whenever there’s a high-stakes test in life, it’s worth your while to cheat a little bit.” The new study is an important contribution to the longstanding debate over how, and why, brightly colored feathers evolved in birds, said Geoffrey Hill, an ornithologist and evolutionary ecologist at Auburn University. “Scientists have spent the last 150 years since Darwin and Wallace trying to understand ornaments in animals and especially colors in birds,” he said. “And this is the kind of original approach that helps us.” © 2021 The New York Times Company

Keyword: Sexual Behavior; Evolution
Link ID: 27781 - Posted: 04.21.2021

By Lisa Sanders, M.D. It was dark by the time the 41-year-old woman was able to start the long drive from her father’s apartment in Washington, D.C., to her home in Westchester County, N.Y. She was eager to get back to her husband and three children. Somewhere after she crossed the border into Maryland, the woman suddenly developed a terrible itch all over her body. She’d been a little itchy for the past couple of weeks but attributed that to dry skin from her now-faded summertime tan. This seemed very different: much stronger, much deeper. And absolutely everywhere, all at the same time. The sensation was so intense it was hard for the woman to pay attention to the road. She found herself driving with one hand on the steering wheel and the other working to respond to her skin’s new need. There was no rash — or at least nothing she could feel — just the terrible itch, so deep inside her skin that she felt as if she couldn’t scratch hard enough to really get to it. By the light of the Baltimore Harbor Tunnel she saw that her nails and fingers were dark with blood. That scared her, and she tried to stop scratching, but she couldn’t. It felt as if a million ants were crawling all over her body. Not on her skin, but somehow under it. The woman had gone to Washington to help her elderly father move. His place was a mess. Many of his belongings hadn’t been touched in years. She figured that she was having a reaction to all the dust and dirt and who knows what else she encountered while cleaning. As soon as she got home, she took a long shower; the cool water soothed her excoriated skin. She lathered herself with moisturizer and sank gratefully into her bed. But the reprieve didn’t last, and from that night on she was tormented by an itch that no scratching could satisfy. © 2021 The New York Times Company

Keyword: Pain & Touch; Hormones & Behavior
Link ID: 27775 - Posted: 04.17.2021

Nicola Davis It is a trope used in films from King Kong to Tarzan – a male primate standing upright and beating its chest, sometimes with a yell and often with more than a dash of hubris. But it seems the pounding action is less about misplaced bravado than Hollywood would suggest: researchers studying adult male mountain gorillas say that while chest-beating might be done to show off, it also provides honest information. “We found it is definitely a real, reliable signal – males are conveying their true size,” said Edward Wright, co-author of the research from the Max Planck Institute for Evolutionary Anthropology in Germany. Advertisement Writing in the journal Scientific Reports, Wright and colleagues report how they studied chest-beating in six adult male mountain gorillas in the Volcanoes national park in Rwanda. The team used a camera setup involving two parallel green lasers a known distance apart to determine the breadth of each gorilla’s back from a photograph. They then recorded 36 chest-beating episodes among these six males between November 2015 and July 2016, and analysed the recordings. The results revealed that the duration of the chest-beating, number of beats and the rate of the beats during an episode were not associated with the size of the gorilla. However, the average peak frequency of the sound produced was – the larger the gorilla, the lower the frequency of the sound produced. © 2021 Guardian News & Media Limited

Keyword: Sexual Behavior; Evolution
Link ID: 27765 - Posted: 04.10.2021

By Jake Buehler Fairy wrasses are swimming jewels, flitting and flouncing about coral reefs. The finger-length fishes’ brash, vibrant courtship displays are meant for mates and rivals, and a new study suggests that the slow waxing and waning of ice sheets and glaciers may be partly responsible for such a variety of performances. A new genetic analysis of more than three dozen fairy wrasse species details the roughly 12 million years of evolution that produced their vast assortment of shapes, colors and behaviors. And the timing of these transformations implies that the more than 60 species of fairy wrasses may owe their great diversity to cyclic sea level changes over the last few millions of years, scientists report February 23 in Systematic Biology. Within the dizzying assembly of colorful reef fishes, fairy wrasses (Cirrhilabrus) can’t help but stand out. They are the most species-rich genus in the second most species-rich fish family in the ocean, says Yi-Kai Tea, an ichthyologist at the University of Sydney. “That is quite a bit of biodiversity,” says Tea, who notes that new fairy wrasse species are identified every year. Despite this taxonomic footprint, Tea says, scientists knew “next to nothing” about the fairy wrasses’ evolutionary history or why there were so many species. © Society for Science & the Public 2000–2021.

Keyword: Sexual Behavior; Evolution
Link ID: 27755 - Posted: 04.03.2021

By Alyson Krueger Samantha LaLiberte, a social worker in Nashville, thought she had made a full recovery from Covid-19. But in mid-November, about seven months after she’d been sick, a takeout order smelled so foul that she threw it away. When she stopped by the house of a friend who was cooking, she ran outside and vomited on the front lawn. “I stopped going places, even to my mom’s house or to dinner with friends, because anything from food to candles smelled so terrible,” Ms. LaLiberte, 35, said. “My relationships are strained.” She is dealing with parosmia, a distortion of smell such that previously enjoyable aromas — like that of fresh coffee or a romantic partner — may become unpleasant and even intolerable. Along with anosmia, or diminished sense of smell, it is a symptom that has lingered with some people who have recovered from Covid-19. The exact number of people experiencing parosmia is unknown. One recent review found that 47 percent of people with Covid-19 had smell and taste changes; of those, about half reported developing parosmia. “That means that a rose might smell like feces,” said Dr. Richard Doty, director of the Smell and Taste Center at the University of Pennsylvania. He noted that people typically recover their smell within months. Right now, Ms. LaLiberte can’t stand the scent of her own body. Showering is no help; the smell of her body wash, conditioner and shampoo made her sick. What’s more, she detected the same odor on her husband of eight years. “There is not a whole lot of intimacy right now,” she said. “And it’s not because we don’t want to.” “It’s a much bigger issue than people give it credit for,” said Dr. Duika Burges Watson, who leads the Altered Eating Research Network at Newcastle University in England and submitted a journal research paper on the topic. “It is something affecting your relationship with yourself, with others, your social life, your intimate relationships.” © 2021 The New York Times Company

Keyword: Chemical Senses (Smell & Taste); Sexual Behavior
Link ID: 27742 - Posted: 03.23.2021

Tinbete Ermyas & Kira Wakeam Roughly 35 bills are being proposed that would limit or prohibit transgender women from competing in women's athletics. Above, athletes run in the Women's 400 meter final during the Rio 2016 Olympic Games. Shaun Botterill/Shaun Botterill/Getty Images Throughout the country, roughly 35 bills have been introduced by state legislators that would limit or prohibit transgender women from competing in women's athletics, according to the LGBTQ rights group Freedom for All Americans. That's up from only two in 2019. The latest action in this push came last week, when Mississippi Governor Tate Reeves signed into law the "Mississippi Fairness Act." The law prohibits schools from allowing transgender female students to compete in female sports and cites "inherent differences between men and women" as one of the reasons to block these athletes from competition. The often heated debates around these bills have centered on whether transgender women and girls have an unfair advantage over cisgender women — a term used for those who identify with the sex assigned to them at birth. Proponents say the legislation is needed in order to maintain fairness in women's athletics by reducing what they believe is an inherent competitive edge of trans athletes who identify as female. Critics call that a false argument and say the proposals are being used as a way to discriminate against transgender Americans. These proposals, they say, also risk opening the door to humiliating treatment of women and girls who don't fit culturally-accepted notions of femininity. Often missing from the culture-war aspect of the debate is a focus on the type of questions that Dr. Eric Vilain has spent much of his career researching. Vilain, a pediatrician and geneticist who studies sex differences in athletes, says there are no good faith reasons to limit transgender women's participation in sports, especially at the high school level. Vilain has advised both the International Olympic Committee and the NCAA, and says these laws generally aren't based in scientific evidence, but rather "target women who have either a different biology or ... simply look different." © 2021 npr

Keyword: Sexual Behavior
Link ID: 27739 - Posted: 03.23.2021

Amanda Heidt In 2015, the National Institute of Neurological Disorders and Stroke released a report stating that more than 600 neurological conditions—including Parkinson’s disease, Alzheimer’s disease, multiple sclerosis, and motor neuron disease, among others—affect an estimated 50 million Americans, a number that is growing each year. Many of these diseases share a common feature in the degradation of the blood-brain barrier (BBB), the cloak of endothelial cells that disposes of the brain’s waste while also providing necessary nutrients. To better understand these diseases and to develop new ways to treat them, scientists rely on increasingly sophisticated cellular models that attempt to mimic the full complexity of the BBB. The advent of hydrogels, microfluidics, and so-called organs on a chip all rely on stable cell lines to build a useful proxy, but new research suggests that all cells may not respond equally to experimentation. The Scientist spoke with Alisa Morss Clyne and Callie Weber, two bioengineers at the University of Maryland whose recent review, published March 16 in APL Bioengineering, makes the case for the inclusion of sex as a biological variable in cell-based experiments. Men and women, a growing body of evidence shows, respond differently to brain diseases in ways that can profoundly influence a study’s findings. Men, for example, are 1.5 times more likely to be diagnosed with Parkinson’s disease and often experience the condition more severely, perhaps because the higher levels of estrogen in premenopausal women shield the BBB from damage. When purchasing cells, Clyne says, scientists are rarely aware of the sex of the original cell donor, but it may ultimately have important consequences for the study of diseases, neurological or otherwise. © 1986–2021 The Scientist

Keyword: Sexual Behavior
Link ID: 27738 - Posted: 03.23.2021

By Elizabeth Pennisi For a glimpse of the power of sexual selection, the dance of the golden-collared manakin is hard to beat. Each June in the rainforests of Panama, the sparrow-size male birds gather to fluff their brilliant yellow throats, lift their wings, and clap them together in rapid fire, up to 60 times a second. When a female favors a male with her attention, he follows up with acrobatic leaps, more wing snaps, and perhaps a split-second, twisting backflip. “If manakins were human, they would be among the greatest artists, athletes, and socialites in our society,” says Ignacio Moore, an integrative organismal biologist at Virginia Polytechnic Institute and State University. As biologists have understood since Charles Darwin, such exhibitionism evolves when females choose to mate with males that have the most extravagant appearances and displays—a proxy for fitness. And now, by studying the genomes of the golden-collared manakin (Manacus vitellinus) and its relatives, researchers are exploring the genes that drive these elaborate behaviors and traits. Last month at the virtual meeting of the Society for Integrative and Comparative Biology, Moore and other researchers introduced four manakin genomes, adding to two already published, and singled out genes at work in the birds’ muscles and brains that may make the displays possible. © 2021 American Association for the Advancement of Science.

Keyword: Sexual Behavior; Evolution
Link ID: 27716 - Posted: 03.06.2021

By Jake Buehler You might be able to do a mean celebrity impression or two, but can you imitate an entire film’s cast at the same time? A male superb lyrebird (Menura novaehollandiae) can, well almost. During courtship and even while mating, the birds pull off a similar feat, mimicking the calls and wingbeat noises of many bird species at once, a new study shows. The lyrebirds appear to be attempting to recreate the specific ecological soundscape associated with the arrival of a predator, researchers report February 25 in Current Biology. Why lyrebirds do this isn’t yet clear, but the finding is the first time that an individual bird has been observed mimicking the sounds of multiple bird species simultaneously. The uncanny acoustic imitation of multispecies flocks adds a layer of complexity to the male lyrebird’s courtship song yet unseen in birds and raises questions about why its remarkable vocal mimicry skills, which include sounds like chainsaws and camera shutters, evolved in the first place. Superb lyrebirds — native to forested parts of southeastern Australia — have a flair for theatrics. The males have exceptionally long, showy tail feathers that are shaken extensively in elaborate mating dances (SN: 6/6/13). The musical accompaniment to the dance is predominantly a medley of greatest hits of the songs of other bird species, the function of which behavioral ecologist Anastasia Dalziell was studying via audio and video recordings of the rituals.

Keyword: Sexual Behavior; Animal Communication
Link ID: 27715 - Posted: 02.28.2021

By Brooke N. Dulka Think back to years past. When you were a kid, you most likely had more friends than you do now. There were probably a lot of children on the playground you considered a friend, but not all of these friendships were very deep. As you grew up, your friendship circle most likely grew smaller. Instead of having many superficial relationships, you now have just a few really important friendships. This is normal. When we are older, we tend to focus on maintaining positive, meaningful relationships. One idea suggests that we become more selective about our friends because we become increasingly aware of our own mortality. In other words, we have future-oriented cognition. However, a recent study published in Science on the wild chimpanzees living in Uganda’s Kibale National Park suggests that our friendships may not actually be tied to thinking about the future. Alexandra Rosati, an evolutionary psychologist at the University of Michigan and one of the study’s lead investigators, had heard about this long-term field study in Uganda. “It seemed like it all could sort of fit together, in this cool way, this primatology data to actually test this idea about human cognition,” she says. Advertisement In this study, a team of researchers analyzed 78,000 hours of observations of 21 male chimpanzees made between 1995 and 2016 at the Kibale National Park. According to Rosati, a unique feature of this study is the value that exists in the long-term collection of data. “We used 20 years of data for this paper. [It] lets us look at this really detailed information about what's going on in these chimpanzees’ social lives,” she says. The findings surprised her. © 2021 Scientific American

Keyword: Stress; Development of the Brain
Link ID: 27681 - Posted: 02.08.2021

by Peter Hess Mice missing a copy of the autism-linked gene MAGEL2 have trouble discerning between a familiar mouse and an unfamiliar one, but treating them with the social hormone vasopressin reverses this deficit, according to a new study. Mutations in or deletions of MAGEL2 are linked to autism and several related conditions, including Prader-Willi syndrome, which is characterized by intellectual disability, poor muscle tone, difficulty feeding and problems with social interactions. The new findings suggest that these social issues in people stem from impairments in vasopressin’s function in a brain region called the lateral septum, which relays signals between the hippocampus and the ventral tegmental area. They also hint that vasopressin treatment could remedy those issues, says Elizabeth Hammock, assistant professor of psychology and neuroscience at Florida State University in Tallahassee, who was not involved with the study. A 2020 study showed that low levels of vasopressin in cerebrospinal fluid can flag many infants who are later diagnosed with autism. But clinical trials have shown that either providing vasopressin or blocking its effects can improve social communication in autistic children. Because of these seemingly contradictory results, “a better understanding of how alterations in the vasopressinergic system leads to social deficits and how vasopressin administration could resolve some of these problems was needed,” says co-lead researcher Freddy Jeanneteau, professor of neuroscience at Montpellier University in Montpellier, France. © 2021 Simons Foundation

Keyword: Autism; Hormones & Behavior
Link ID: 27665 - Posted: 01.27.2021

Catherine S. Woolley, Ph.D. Sex differences in the brain are real, but they are not what you might think. They’re not about who is better at math, reading a map, or playing chess. They’re not about being sensitive or good at multi-tasking, either. Sex differences in the brain are about medicine and about making sure that the benefits of biomedical research are relevant for everyone, both men and women. You may be surprised to learn that most animal research is done in males. This is based on an erroneous view that hormonal cycles complicate studies in female research animals, and an assumption that the sexes are essentially the same down at cellular and molecular levels. But these beliefs are starting to change in neuroscience. New research shows that some fundamental molecular pathways in the brain operate differently in males and females, and not just by a little. In some cases, molecular sex differences are all-or-nothing. Recognition that male and female brains differ at a molecular level has the potential to transform biomedical research. Drugs act on molecular pathways. If those pathways differ between the sexes, we need to know how they differ as early as possible in the long (and expensive) process of developing new medicines and treatments for disease. The bulk of public attention to brain sex differences is focused on structural differences and their purported relationship to behavior or cognition. Yet structural sex differences are actually quite small, and their interpretation is often based on gender stereotypes with little to no scientific justification. © 2021 The Dana Foundation

Keyword: Sexual Behavior; Brain imaging
Link ID: 27650 - Posted: 01.15.2021

by Peter Hess Two types of neurons process social information, a new mouse study suggests, but only one is disrupted in mice missing the autism-linked gene FMR1. The neurons reside in a brain region called the hypothalamus, and both send signals via the hormone oxytocin. The deletion of FMR1, however, affects these cells differently: The loss of FMR1 in the smaller, ‘parvocellular’ neurons diminishes the mice’s interest in social interactions — but only those involving peers, the new work shows. The gene’s loss from the larger, ‘magnocellular’ neurons, by contrast, does not disrupt the animals’ interactions with either peers or parents. “There are a lot of different types of social behaviors, and not all of them are impaired in autism,” says lead investigator Gül Dölen, assistant professor of neuroscience at Johns Hopkins University in Baltimore, Maryland. Whereas peer-to-peer social interactions are troublesome for many autistic people, other social interactions — such as parental connections — are on par with those seen in non-autistic people, she says. This new understanding of the different neurons’ functions could help explain why clinical trials of oxytocin for treating autism traits have shown mixed results. It could also help scientists develop more effective treatments, experts say. “There are these two different kinds of neurons that we’ve known about for a really long time, and each of their contributions to social behavior has never really been dissected out,” says Larry Young, chief of behavioral neuroscience and psychiatric disorders at Emory University in Atlanta, Georgia, who was not involved with the study. “It’s really important for the future of drug development.” © 2020 Simons Foundation

Keyword: Autism; Hormones & Behavior
Link ID: 27632 - Posted: 12.19.2020