Heidi Ledford When Naomi Rance first started studying menopause and the brain, she pretty much had the field to herself. And what she was discovering surprised her. In studies of post-mortem brains, she had found neurons in a region called the hypothalamus that roughly doubled in size in women after menopause1. “This was changing so much in postmenopausal women,” says Rance, a neuropathologist at the University of Arizona in Tucson. “It had to be important.” This was the 1990s, and few other researchers were interested. Rance forged ahead on her own, painstakingly unravelling what the neurons were doing and finessing a way to study menopause symptoms in rats by tracking tiny temperature changes in their tails as a measure of hot flushes, a common symptom of menopause that is thought to be triggered in the hypothalamus. Thirty years later, a drug called fezolinetant, based on Rance’s discoveries, is being evaluated by the US Food and Drug Administration, with an approval decision expected in the first half of this year. If approved, fezolinetant could be a landmark: the first non-hormonal therapy to treat the source of hot flushes, a symptom that has become nearly synonymous with menopause and one that is experienced by about 80% of women going through the transition. (This article uses ‘women’ to describe people who experience menopause, while recognizing that not all people who identify as women go through menopause, and not all people who go through menopause identify as women.) Rance and others in the field, fezolinetant’s progress to this point is a sign that research into the causes and effects of menopausal symptoms is finally being taken seriously. In the next few years, the global number of postmenopausal women is expected to surpass one billion. But many women still struggle to access care related to menopause, and research into how best to manage such symptoms has lagged behind. That is slowly changing. Armed with improved animal models and a growing literature on the effects of existing treatments, more researchers are coming into the field to fill that gap. © 2023 Springer Nature Limited

Keyword: Hormones & Behavior; Learning & Memory
Link ID: 28778 - Posted: 05.10.2023

By Erin Blakemore Newly published research suggests that the sons of women with polycystic ovary syndrome (PCOS) are up to twice as likely to develop obesity as their peers. The study in Cell Reports Medicine used data from cohort research following 467,275 male infants born in Sweden between July 2006 and December 2015. Of those, 9,828 were born to a mother with PCOS — and 147 of those boys were eventually diagnosed with obesity. About 2 in 100 Swedish boys who were born to mothers with PCOS became obese during childhood, compared with about 1 in 100 for boys whose mothers did not have PCOS. The risk was higher among the sons of women who had PCOS and a body mass index (BMI) greater than 25 and highest among the sons of women who both had PCOS and did not take metformin during pregnancy. Researchers followed up the analysis with an RNA sequencing study that found higher cholesterol in sons of Chilean women with PCOS than controls. In another analysis, researchers fed a group of mice a fatty, sugary diet and exposed them to high levels of dihydrotestosterone, a hormone that mimics that of pregnant women with PCOS. Their sons were born with metabolic problems that persisted into adulthood, even when they ate a healthy diet throughout their lives. “We could see that these male mice had more fat tissue, larger fat cells, and a disordered basal metabolism, despite eating a healthy diet,” says Elisabet Stener-Victorin, a reproductive endocrinology and metabolism investigator at the Karolinska Institute in Sweden and the study’s lead author, in a news release.

Keyword: Obesity; Hormones & Behavior
Link ID: 28776 - Posted: 05.10.2023

By Freda Kreier Pregnancy can do weird things to the body. For some bats, it can hamper their ability to “see” the world around them. Kuhl’s pipistrelle bats (Pipistrellus kuhlii) echolocate less frequently while pregnant, researchers report March 28 in BMC Biology. The change may make it harder for the tiny bats to detect prey and potential obstacles in the environment. The study is among the first to show that pregnancy can shape how nonhuman mammals sense their surroundings, says Yossi Yovel, a neuroecologist at Tel Aviv University in Israel. Nocturnal bats like Kuhl’s pipistrelles famously use sound to navigate and hunt prey in the dark (SN: 9/20/17). Their calls bounce off whatever is nearby and bats use the echoes to reconstruct what’s around them, a process aptly named echolocation. The faster a bat makes calls, the better it can make out its surroundings. But rapid-fire calling requires breathing deeply, which is something that pregnancy can get in the way of. “Although I’ve never been pregnant, I know that when I eat a lot, it’s more difficult to breathe,” Yovel says. So pregnancy — which can add a full gram to a 7-gram Kuhl’s pipistrelle and may push up on the lungs — might hamper echolocation. Yovel and colleagues tested their hypothesis by capturing 10 Kuhl’s pipistrelles, five of whom were pregnant, and training the bats to find and land on a platform. Recordings of the animals’ calls revealed that bats that weren’t pregnant made around 130 calls on average while searching for the platform. But bats that were pregnant made only around 110 calls, or 15 percent fewer. © Society for Science & the Public 2000–2023.

Keyword: Hearing; Hormones & Behavior
Link ID: 28774 - Posted: 05.10.2023

Jon Hamilton Boys born to mothers who got COVID-19 while pregnant appear nearly twice as likely as other boys to be diagnosed with subtle delays in brain development. That's the conclusion of a study of more than 18,000 children born at eight hospitals in Eastern Massachusetts. Nearly 900 of the children were born to mothers who had COVID during their pregnancy. In the study, boys, but not girls, were more likely to be diagnosed with a range of developmental disorders in the first 18 months of life. These included delays in speech and language, psychological development and motor function, as well as intellectual disabilities. In older children, these differences are often associated with autism spectrum disorder, says Dr. Roy Perlis, a co-author of the study and a psychiatrist at Massachusetts General Hospital. But for the young children in this study, "it's way too soon to reliably diagnose autism," Perlis says. "All we can hope to detect at this point are more subtle sorts of things like delays in language and speech, and delays in motor milestones." The study, which relied on an analysis of electronic health records, was published in March in the journal JAMA Network Open. The finding is just the latest to suggest that a range of maternal infections can alter fetal brain development, especially in male offspring. For example, studies have found links between infections like influenza and cytomegalovirus, and disorders like autism and schizophrenia. "Male fetuses are known to be more vulnerable to maternal infectious exposures during pregnancy," says Dr. Andrea Edlow, the study's lead author and a maternal-fetal medicine specialist at Massachusetts General Hospital. © 2023 npr

Keyword: Development of the Brain; Sexual Behavior
Link ID: 28743 - Posted: 04.18.2023

By Azeen Ghorayshi Morénike Giwa Onaiwu was shocked when day care providers flagged some concerning behaviors in her daughter, Legacy. The toddler was not responding to her name. She avoided eye contact, didn’t talk much and liked playing on her own. But none of this seemed unusual to Dr. Onaiwu, a consultant and writer in Houston. “I didn’t recognize anything was amiss,” she said. “My daughter was just like me.” Legacy was diagnosed with autism in 2011, just before she turned 3. Months later, at the age of 31, Dr. Onaiwu was diagnosed as well. Autism, a neurodevelopmental disorder characterized by social and communication difficulties as well as repetitive behaviors, has long been associated with boys. But over the past decade, as more doctors, teachers and parents have been on the lookout for early signs of the condition, the proportion of girls diagnosed with it has grown. In 2012, the Centers for Disease Control and Prevention estimated that boys were 4.7 times as likely as girls to receive an autism diagnosis. By 2018, the ratio had dipped to 4.2 to 1. And in data released by the agency last month, the figure was 3.8 to 1. In that new analysis, based on the health and education records of more than 226,000 8-year-olds across the country, the autism rate in girls surpassed 1 percent, the highest ever recorded. More adult women like Dr. Onaiwu are being diagnosed as well, raising questions about how many young girls continue to be missed or misdiagnosed. “I think we just are getting more aware that autism can occur in girls and more aware of the differences,” said Catherine Lord, a psychologist and autism researcher at the University of California, Los Angeles. © 2023 The New York Times Company

Keyword: Autism; Sexual Behavior
Link ID: 28737 - Posted: 04.12.2023

By Bethany Brookshire Cockroaches are changing up their sex lives, and it’s all our fault. Faced with sweet poisoned bait, roaches first ended up with a mutation that made them hate sweets, hindering their mating strategies. Now, more roach mutations are emerging, showing you can’t keep a good pest down. Like many animals, cockroaches have a sweet tooth, and that preference for sugar plays a central role in their reproductive activities. When a male roach targets a female roach, he will back up to her, secreting a solution called a nuptial gift from the tergal gland under his wings. The solution is full of proteins, fats and sugars, what some researchers call the chocolate of roach food. The female cockroach will crawl up on his back to take a sample, and while she is occupied, the male will whip out a hooked penis to latch onto her reproductive tract. They will then turn back to back and do the deed for about 90 minutes. Humans have aimed to exploit this love of sweet stuff to push cockroaches — particularly the German cockroaches that turn up in American homes — out of our spaces. For decades, people used poisoned roach baits baited with solutions containing glucose. Cockroaches took the bait. But some time in the late 20th century, a new mutation arose — glucose aversion. No one knows how many roaches now hate the sweet stuff, but Coby Schal, an evolutionary biologist at North Carolina State University, suspects the mutation is very common. “There are more and more papers being published on the fact that a whole suite of baits don’t work so well,” he said. This lack of a sweet tooth saved cockroaches from death, but it hurt their sex lives. The gift that normal males secrete contains maltose, a sugar that cockroach saliva transforms into glucose. But if females had the glucose averse mutation, they did not find the male secretions sexy and turned away before the male could hook on. © 2023 The New York Times Company

Keyword: Chemical Senses (Smell & Taste); Evolution
Link ID: 28722 - Posted: 03.29.2023

By Azeen Ghorayshi For decades, male mice have been the default in scientific experiments that test new drugs or examine the connections of the brain. The reason? Female mice, which experience a four- to five-day cycle of fluctuating ovarian hormones, were thought to be too complicated. Accounting for the hormonal changes was viewed as too cumbersome and too expensive. But the estrous cycle has little to do with how female mice behave, according to a new study that used machine-learning software to track the second-to-second behavior of animals exploring an open space. Male mice actually exhibited more erratic behavior than females did. The study, published in the journal Current Biology on Tuesday, challenges century-old stereotypes that kept female animals out of laboratory research — and, until the 1990s, barred women from clinical trials. The new research is “tipping all of these assumptions about sex differences and the influence of hormones on their head,” said Rebecca Shansky, a behavioral neuroscientist at Northeastern University and a co-author of the new study. The cost of excluding females — whether human or animal — from scientific research is high. Women are almost twice as likely as men to experience severe side effects from drugs, most of which have dosages based on the initial testing done in men. Women also may not derive the same benefits from the drugs. Women “capable of becoming pregnant,” as the federal government put it, were largely excluded from clinical trials of drugs until 1993, when a new law required researchers funded by the National Institutes of Health to include women and minority groups. In the decades since, women have made up close to half of clinical research participants, though they still lag behind in studies of certain drugs, like those used to treat cardiovascular disease and psychiatric disorders. But a large sex gap persisted in basic science research using lab animals, studies that pave the way to medical breakthroughs. In neuroscience, according to a review published in 2010, studies of male lab animals outnumbered female ones by a factor of five. © 2023 The New York Times Company

Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 28694 - Posted: 03.08.2023

Heidi Ledford Under the right circumstances, even moderately hungry mice prefer to socialize with the opposite sex than to eat, researchers have found1. In research published on 23 February in Cell Metabolism, scientists treated male mice with a technique that mimics the effects of leptin, a hormone that acts on the brain to suppress appetite. Treated mice were more likely to approach female mice than their food bowls — even if the test rodents had been deprived of food for almost an entire day. The findings reveal a surprising role for leptin in social behaviour. They are also a step towards understanding how animals prioritize different behavioural options in response to ongoing needs — an enduring question in neuroscience, says Gina Leinninger, who studies the neural regulation of feeding at Michigan State University in East Lansing. The paper “addresses a huge gap in the field”, she says. “When you no longer need to eat urgently, it should free you up to do other things.” The new work, Leinninger says, illuminates how the brain juggles these various demands. Food versus friends Neuroscientists Anne Petzold and Tatiana Korotkova at the University of Cologne in Germany, and their colleagues, sought to understand how such decision-making is affected by leptin, which activates a subset of cells in the brain and promotes a feeling of fullness. The researchers injected male mice with leptin and saw that it suppressed feeding, as expected — but also promoted interactions with female mice. The team examined neurons in the brain’s ‘hunger center’, the lateral hypothalamus, that are activated by leptin. The authors’ experiments showed that neurons that can sense leptin were activated when mice interacted with members of the opposite sex. Artificially activating those neurons using a technique called optogenetics raised the likelihood that a mouse would approach a member of the opposite sex. Both results suggest that leptin plays a part in promoting social behaviour. © 2023 Springer Nature Limited

Keyword: Obesity; Sexual Behavior
Link ID: 28682 - Posted: 02.25.2023

By Virat Markandeya It’s evening at the northern tip of the Red Sea, in the Gulf of Aqaba, and Tom Shlesinger readies to take a dive. During the day, the seafloor is full of life and color; at night it looks much more alien. Shlesinger is waiting for a phenomenon that occurs once a year for a plethora of coral species, often several nights after the full moon. Guided by a flashlight, he spots it: coral releasing a colorful bundle of eggs and sperm, tightly packed together. “You’re looking at it and it starts to flow to the surface,” Shlesinger says. “Then you raise your head, and you turn around, and you realize: All the colonies from the same species are doing it just now.” Some coral species release bundles of a pinkish- purplish color, others release ones that are yellow, green, white or various other hues. “It’s quite a nice, aesthetic sensation,” says Shlesinger, a marine ecologist at Tel Aviv University and the Interuniversity Institute for Marine Sciences in Eilat, Israel, who has witnessed the show during many years of diving. Corals usually spawn in the evening and night within a tight time window of 10 minutes to half an hour. “The timing is so precise, you can set your clock by the time it happens,” Shlesinger says. Moon-controlled rhythms in marine critters have been observed for centuries. There is calculated guesswork, for example, that in 1492 Christopher Columbus encountered a kind of glowing marine worm engaged in a lunar-timed mating dance, like the “flame of a small candle alternately raised and lowered.” Diverse animals such as sea mussels, corals, polychaete worms and certain fishes are thought to synchronize their reproductive behavior by the moon. The crucial reason is that such animals — for example, over a hundred coral species at the Great Barrier Reef — release their eggs before fertilization takes place, and synchronization maximizes the probability of an encounter between eggs and sperm. © 2023 Annual Reviews

Keyword: Biological Rhythms; Sexual Behavior
Link ID: 28681 - Posted: 02.25.2023

By Erin Garcia de Jesús A female giraffe has a great Valentine’s Day gift for potential mates: urine. Distinctive anatomy helps male giraffes get a taste for whether a female is ready to mate, animal behaviorists Lynette and Benjamin Hart report January 19 in Animals. A pheromone-detecting organ in giraffes has a stronger connection to the mouth than the nose, the researchers found. That’s why males scope out which females to mate with by sticking their tongues in a urine stream. Animals such as male gazelles will lick fresh urine on the ground to track if females are ready to mate. But giraffes’ long necks and heavy heads make bending over to investigate urine on the ground an unstable and vulnerable position, says Lynette Hart, of the University of California, Davis. The researchers observed giraffes (Giraffa giraffa angolensis) in Etosha National Park in Namibia in 1994, 2002 and 2004. Bull giraffes nudged or kicked the female to ask her to pee. If she was a willing participant, she urinated for a few seconds, while the male took a sip. Then the male curled his lip and inhaled with his mouth, a behavior called a flehmen response, to pull the female’s scent into two openings on the roof of the mouth. From the mouth, the scent travels to the vomeronasal organ, or VNO, which detects pheromones. The Harts say they never saw a giraffe investigate urine on the ground. Unlike many other mammals, giraffes have a stronger oral connection — via a duct — to the VNO, than a nasal one, examinations of preserved giraffe specimens showed. One possible explanation for the difference could be that a VNO-nose link helps animals that breed at specific times of the year detect seasonal plants, says Benjamin Hart, a veterinarian also at the University of California, Davis. But giraffes can mate any time of year, so the nasal connection may not matter as much. © Society for Science & the Public 2000–2023.

Keyword: Chemical Senses (Smell & Taste); Sexual Behavior
Link ID: 28664 - Posted: 02.15.2023

By Elizabeth Preston A fully grown male orca is one of the planet’s fiercest hunters. He’s a wily, streamlined torpedo who can weigh as much as 11 tons. No other animal preys on him. Yet in at least one population, these apex predators struggle to survive without their moms, who catch their food and even cut it up for them. Scientists have previously seen that some killer whale mothers share food with their grown sons. In a study published Wednesday in Current Biology, researchers found that this prolonged feeding carries a huge reproductive cost for mothers. Killer whales, actually the largest members of the dolphin family, swim throughout the world’s oceans. Yet they live in discrete populations with their own territories, dialects and hunting customs. A group that spends much of the year off the coast of British Columbia, Washington and Oregon is known as the southern residents. They eat mainly Chinook salmon, which have been increasingly hard to find. “Killer whales worldwide are doing fine,” said Michael Weiss, research director at the Center for Whale Research in Friday Harbor, Wash. But the southern residents, with a population of just 73, are considered endangered. These whales stay with their birth family for their whole lives. The families are led by matriarchs who can live 80 to 90 years. Yet the females stop reproducing in midlife: Orcas and a few other whale species are the only mammals, besides humans, known to undergo menopause. To try to explain menopause, scientists have looked for ways that matriarchs encourage the survival of their children and grandchildren. A 2012 study of southern resident killer whales, along with their neighbors, the northern residents, showed that the presence of older moms helped adult offspring stay alive — especially sons. Males over age 30 were eight times more likely to die in the year following their own mothers’ deaths. © 2023 The New York Times Company

Keyword: Sexual Behavior; Evolution
Link ID: 28662 - Posted: 02.11.2023

By Susan Dominus For the past two or three years, many of my friends, women mostly in their early 50s, have found themselves in an unexpected state of suffering. The cause of their suffering was something they had in common, but that did not make it easier for them to figure out what to do about it, even though they knew it was coming: It was menopause. The symptoms they experienced were varied and intrusive. Some lost hours of sleep every night, disruptions that chipped away at their mood, their energy, the vast resources of good will that it takes to parent and to partner. One friend endured weeklong stretches of menstrual bleeding so heavy that she had to miss work. Another friend was plagued by as many as 10 hot flashes a day; a third was so troubled by her flights of anger, their intensity new to her, that she sat her 12-year-old son down to explain that she was not feeling right — that there was this thing called menopause and that she was going through it. Another felt a pervasive dryness in her skin, her nails, her throat, even her eyes — as if she were slowly calcifying. Then last year, I reached the same state of transition. Technically, it is known as perimenopause, the biologically chaotic phase leading up to a woman’s last period, when her reproductive cycle makes its final, faltering runs. The shift, which lasts, on average, four years, typically starts when women reach their late 40s, the point at which the egg-producing sacs of the ovaries start to plummet in number. In response, some hormones — among them estrogen and progesterone — spike and dip erratically, their usual signaling systems failing. During this time, a woman’s period may be much heavier or lighter than usual. As levels of estrogen, a crucial chemical messenger, trend downward, women are at higher risk for severe depressive symptoms. Bone loss accelerates. In women who have a genetic risk for Alzheimer’s disease, the first plaques are thought to form in the brain during this period. Women often gain weight quickly, or see it shift to their middles, as the body fights to hold onto the estrogen that abdominal fat cells produce. The body is in a temporary state of adjustment, even reinvention, like a machine that once ran on gas trying to adjust to solar power, challenged to find workarounds. © 2023 The New York Times Company

Keyword: Hormones & Behavior; Sexual Behavior
Link ID: 28658 - Posted: 02.08.2023

By McKenzie Prillaman A newfound species of frog doesn’t ribbit. In fact, it doesn’t make any sound at all. Many frogs have unusual characteristics, from turning translucent to being clumsy jumpers (SN: 12/22/22; 6/15/22). The recently discovered amphibian lacks a voice. It joins a group of seven other voiceless frog species called spiny-throated reed frogs that reside in East Africa. Instead of croaking, the spines on male frogs’ throats might help their female counterparts recognize potential mates via touch, sort of like braille, says conservation biologist Lucinda Lawson of the University of Cincinnati. Lawson and colleagues spotted the little frog, only about 25 millimeters long, in 2019 while surveying wildlife in Tanzania’s Ukaguru Mountains. The team immediately recognized the animal, now named Hyperolius ukaguruensis, as a spiny-throated reed frog. But something seemed off. “It [was] the wrong color,” Lawson says. Most frogs from this group are green and silver, but this one was gold and brown. Some quick measurements to check if the peculiar frog simply had trivial color variations or if it could be a new species revealed that its eyes were smaller than other spiny-throated reed frogs. The researchers agreed: “Let’s do some genetics,” Lawson says. They ran DNA tests on two frogs that looked like they belonged to the suspected new species, as well as 10 individuals belonging to known spiny-throated species. Comparing the golden frogs’ genetic makeup with that of the others revealed the oddballs were genetically distinct, Lawson and colleagues report February 2 in PLOS ONE. © Society for Science & the Public 2000–2023.

Keyword: Animal Communication; Sexual Behavior
Link ID: 28655 - Posted: 02.04.2023

Heidi Ledford The humble prairie vole (Microtus ochrogaster) has long been revered for its unusual commitment to family. Pair-bonded couples huddle together, raise pups together and mate exclusively together — at least most of the time. Drop another couple’s pups into a cage with pair-bonded prairie voles and the adults will often foster those young as their own — highly unusual behaviour for a rodent. But a study published on 27 January in Neuron1 challenges decades of research that suggests a protein that detects the ‘love hormone’ oxytocin is responsible for the voles’ domestic bliss. Using CRISPR gene-editing, researchers found that prairie voles lacking the protein were still responsible parents and still formed monogamous relationships. These surprising results highlight the importance of revisiting accepted dogma when new scientific techniques emerge, says neuroscientist Bianca Jones Marlin at the Columbia University Zuckerman Institute in New York City. “Neuroscientists grew up in our field understanding that prairie voles pair bonded because of the distribution of oxytocin receptors and oxytocin,” she says. “That was canon.” For decades, neuroscientists interested in understanding the biological underpinnings of human social behaviours have been fascinated by prairie voles. “There’s a sort of eerie similarity between prairie vole social behaviours and human social behaviours,” says Nirao Shah, a neuroscientist at Stanford University in California. “Prairie voles are one of the few mammalian species that exhibit social attachment.” Social attachment The hormone oxytocin has long been thought to have a pivotal role in social behaviours. A protein that binds to oxytocin, called oxytocin receptor, is expressed differently in prairie vole brains than in the brains of other voles that do not form monogamous relationships. In humans, oxytocin levels rise in response to social interactions, and the hormone is important in stimulating uterine contractions during childbirth and the production of milk afterwards. © 2023 Springer Nature Limited

Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 28653 - Posted: 02.01.2023

By Jake Buehler Female snakes have clitorises too, a new study finds. The research raises the possibility that the sex lives of snakes are more complicated and diverse than previously understood, researchers report December 14 in Proceedings of the Royal Society B. Clitorises are found in a wide range of vertebrate life, from crocodiles to dolphins (SN: 1/10/22). One exception is birds, which lost their clitorises over the course of their evolution. Female snakes appeared to have lost the sex organ too, which was puzzling, since their close lizard relatives possess paired clitorises, called hemiclitorises. Male lizards and snakes have accompanying paired phalli, or hemipenises.  This element of female snakes’ sexual anatomy went unexamined in detail for so long partly because hemiclitorises can be fragile and easy to miss, but also because female genitalia have historically been considered “quite taboo,” says evolutionary biologist Megan Folwell of the University of Adelaide in Australia. “Even in humans, the proper function and significance of the human clitoris was still being discussed in 2006,” she says. Conflicting accounts of snake hemiclitorises in some scientific papers led Folwell to take a detailed look. She first examined a euthanized female common death adder (Acanthophis antarcticus). “I just started with dissecting the tail and going into it with a really open mind of what I might find,” she says. She was “pleasantly surprised” to find dual organs within that were completely different from the hemipenises found in male snakes. Also, unlike lizard hemiclitorises, the snake’s couldn’t turn out externally. © Society for Science & the Public 2000–2022.

Keyword: Sexual Behavior; Evolution
Link ID: 28594 - Posted: 12.15.2022

By Bonnie Berkowitz and  William Neff Creating a physique that can win at the highest level of professional bodybuilding requires superhuman self-discipline, intense training and genetic good fortune. Increasingly, say the people familiar with the culture and its consequences, it cannot be done without illicit drugs and a willingness to push a body to — or past — its limits. More than a dozen scientists, trainers, judges and competitors interviewed for this report said that just earning a pro card, an amateur’s ticket to the pro ranks, is very difficult without anabolic steroids. Winning a marquee title drug-free? Several people laughed at the question. “Impossible,” said Harrison Pope, one of the country’s leading anabolic-steroid researchers. The behemoths who win the best-known and most lucrative titles barely resemble the iconic, classically muscled champions of the past, such as Arnold Schwarzenegger, who won the sport’s premiere title, Mr. Olympia, seven times between 1970 and 1980. “Arnold Schwarzenegger would not win today,” said Brad Schoenfeld, a professor at Lehman College in New York and author of several books on bodybuilding and muscle growth. “He would not even get a pro card.” Although bodybuilders spend years lifting weights and honing each muscle, they don’t need to demonstrate strength for the judges beyond the ability to hold poses onstage. They only need to look strong. Some competitors — and a growing legion of young, mostly male admirers — chase that look by diving into a reckless pharmacological game of whack-a-mole that insiders say has grown more intense and dangerous as sheer size has trumped the “Greek god” ideal of previous generations.

Keyword: Hormones & Behavior; Drug Abuse
Link ID: 28588 - Posted: 12.10.2022

Darby Saxbe The time fathers devote to child care every week has tripled over the past 50 years in the United States. The increase in fathers’ involvement in child rearing is even steeper in countries that have expanded paid paternity leave or created incentives for fathers to take leave, such as Germany, Spain, Sweden and Iceland. And a growing body of research finds that children with engaged fathers do better on a range of outcomes, including physical health and cognitive performance. Despite dads’ rising participation in child care and their importance in the lives of their kids, there is surprisingly little research about how fatherhood affects men. Even fewer studies focus on the brain and biological changes that might support fathering. It is no surprise that the transition to parenthood can be transformative for anyone with a new baby. For women who become biological mothers, pregnancy-related hormonal changes help to explain why a new mother’s brain might change. But does fatherhood reshape the brains and bodies of men – who don’t experience pregnancy directly – in ways that motivate their parenting? We set out to investigate this question in our recent study of first-time fathers in two countries. Recent research has found compelling evidence that pregnancy can enhance neuroplasticity, or remodeling, in the structures of a woman’s brain. Using magnetic resonance imaging, researchers have identified large-scale changes in the anatomy of women’s brains from before to after pregnancy. In one study, researchers in Spain scanned first-time mothers before conceiving, and again at two months after they gave birth. Compared with childless women, the new mothers’ brain volume was smaller, suggesting that key brain structures actually shrank in size across pregnancy and the early postpartum period. The brain changes were so pronounced that an algorithm could easily differentiate the brain of a woman who had gone through a pregnancy from that of a woman with no children. Copyright © 2010–2022, The Conversation US, Inc.

Keyword: Sexual Behavior; Brain imaging
Link ID: 28576 - Posted: 12.03.2022

By Ingrid Wickelgren  Science has largely neglected pregnancy’s effect on the brain, even though it involves dramatic surges in steroid hormones, which are known to alter the organ. A decade ago neuroscientist Elseline Hoekzema, then a young postdoctoral fellow thinking about having her first child, and two of her female colleagues set out to bridge the knowledge gap. “There’s this enormous event involving such strong hormone changes,” says Hoekzema, now at Amsterdam University Medical Center. “It’s really weird that so little was known about this.” Their initial study, published in 2016, revealed for the first time that pregnancy produced significant structural changes in a woman’s brain that endured for at least two years after birth. Now in a new seven-year study, Hoekzema and her colleagues have seen the same structural changes in different women and have shown that pregnancy also alters the function of a key brain network involved in self-reflection. According to the work, which appeared on Nov. 22 in Nature Communications, the brain changes correlate with a mother’s enhanced bonding with her baby. The findings were derived from examining the female participants’ physiology and using questionnaires to assess their behavior and mental state. And for the first time in humans, the researchers found strong evidence that female hormones are behind it all. The biggest changes occur in a brain network that is active when the brain is idling—that is, when it is not engaged in any particular task—suggesting that pregnancy alters the organ’s baseline state. “[The researchers] are seeing these functional connectivity changes even at rest,” says Jodi Pawluski, a neuroscientist at the University of Rennes 1 in France, who studies the maternal brain and perinatal mental illness but was not involved in the study. “That speaks to the significance of this stage in a birthing person’s life and how it really is transformative in the brain.”

Keyword: Hormones & Behavior; Sexual Behavior
Link ID: 28566 - Posted: 11.23.2022

By Megan Twohey and Christina Jewett The medical guidance was direct. Eleven-year-old Emma Basques had identified as a girl since toddlerhood. Now, as she worried about male puberty starting, a Phoenix pediatrician advised: Take a drug to stop it. At 13, Jacy Chavira felt increasingly uncomfortable with her maturing body and was beginning to believe she was a boy. Use the drug, her endocrinologist in Southern California recommended, and puberty would be suspended. An 11-year-old in New York with deepening depression expressed a desire to no longer be a girl. A therapist told the family the drug was the preteen’s best option, and a local doctor agreed. “‘Puberty blockers really help kids like this,’” the child’s mother recalled the therapist saying. “It was presented as a tourniquet that would stop the hemorrhaging.” As the number of adolescents who identify as transgender grows, drugs known as puberty blockers have become the first line of intervention for the youngest ones seeking medical treatment. Their use is typically framed as a safe — and reversible — way to buy time to weigh a medical transition and avoid the anguish of growing into a body that feels wrong. Transgender adolescents suffer from disproportionately high rates of depression and other mental health issues. Studies show that the drugs have eased some patients’ gender dysphoria — a distress over the mismatch of their birth sex and gender identity. “Anxiety drains away,” said Dr. Norman Spack, who pioneered the use of puberty blockers for trans youth in the United States and is one of many physicians who believe the drugs can be lifesaving. “You can see these kids being so relieved.” But as an increasing number of adolescents identify as transgender — in the United States, an estimated 300,000 ages 13 to 17 and an untold number who are younger — concerns are growing among some medical professionals about the consequences of the drugs, a New York Times examination found. The questions are fueling government reviews in Europe, prompting a push for more research and leading some prominent specialists to reconsider at what age to prescribe them and for how long. A small number of doctors won’t recommend them at all. © 2022 The New York Times Company

Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 28555 - Posted: 11.16.2022

By Hannah Thomasy Ned and Sunny stretch out together on the warm sand. He rests his head on her back, and every so often he might give her an affectionate nudge with his nose. The pair is quiet and, like many long-term couples, they seem perfectly content just to be in each other’s presence. The couple are monogamous, which is quite rare in the animal kingdom. But Sunny and Ned are a bit scalier that your typical lifelong mates — they are shingleback lizards that live at Melbourne Museum in Australia. In the wild, shinglebacks regularly form long-term bonds, returning to the same partner during mating season year after year. One lizard couple in a long-term study had been pairing up for 27 years and were still going strong when the study ended. In this way, the reptiles are more like some of the animal kingdom’s most famous long-term couplers, such as albatrosses, prairie voles and owl monkeys, and they confound expectations many people have about the personalities of lizards. “There’s more socially going on with reptiles than we give them credit for,” said Sean Doody, a conservation biologist at the University of South Florida. Social behavior in reptiles has been largely overlooked for decades, but a handful of dedicated scientists have begun unraveling reptiles’ cryptic social structures. With the help of camera traps and genetic testing, scientists have discovered reptiles living in family groups, caring for their young and communicating with each other in covert ways. And they aren’t only doing this because they love lizards. Currently, one in five reptile species are threatened with extinction; researchers say learning more about reptile sociality could be crucial for conservation. Humans have a long history of animosity toward reptiles, and influential twentieth century scientists added to the idea of reptiles as cold, unintelligent beasts. In the mid-1900s, Paul MacLean, a neuroscientist at Yale and then the National Institute of Mental Health, began developing the triune brain hypothesis. He theorized that the human brain contained three parts: the reptilian R-complex, which governed survival and basic instinctual behaviors; the paleomammalian complex, which controlled emotional behavior; and the neomammalian cortex, which was responsible for higher functions like problem-solving and language. © 2022 The New York Times Company

Keyword: Sexual Behavior; Evolution
Link ID: 28528 - Posted: 10.26.2022