By Susan Dominus Spend enough time speaking to women who are taking testosterone — specifically, in very high doses — and you start to notice that they sound messianic. They’re often talking fast and intensely; they’re amped up; they’re describing what they clearly consider a miracle drug; and they have no intention of lowering their dose, despite the unknown risks or some problems with facial hair. After all, how can they worry about facial hair when they feel so alive? It’s nothing they can’t take care of with a quick waxing, which they now have the energy to do at the end of the day — right after they prepare a high-protein dinner for their family and before they put the finishing touches on their spreadsheets, close their laptops and light a few mood candles for the sex that they know will be great, maybe even better than the sex they had last night, even though they’re a day older. “It’s changed my marriage,” Jessica Medina, a 41-year-old marketing consultant in Orange County, Calif., told me. With four kids in the house, and sex happening six times a week (up from “How about never?” pre-testosterone), she had to put a lock on the bedroom door. She and her husband had attended a “marriage growth” group at church for years, but it took testosterone for their relationship to be, as she put it, “100 times closer.” She was a little less emotional, a little less sentimental than she used to be, but she didn’t have time for that kind of thing, anyway. “It’s more like: Get stuff done, handle business, work out,” she said. “In order to do all that and still have time for our kids and their sports, there’s no time to whine about how hard it is.” Catherine Lin, a single mother who ran a bicoastal fashion media company, went on testosterone in her early 40s to raise her energy. She got the boost she wanted, started lifting heavier weights, decided to pursue a degree in holistic nutrition and enjoyed an unexpected side effect: She started having orgasms for the first time in years. © 2025 The New York Times Company

Keyword: Hormones & Behavior; Sexual Behavior
Link ID: 29978 - Posted: 10.22.2025

By Claudia López Lloreda Mouse pups, like other infants across the animal kingdom, cry to get their mother’s attention. The oxytocin system drives this communication and shapes how baby mice interact when reunited with their mothers, according to a study out today in Science. Oxytocin, known colloquially as the “love” or “cuddle” hormone, stimulates milk release during nursing and promotes maternal care behaviors. But most oxytocin research thus far has focused solely on the mother, overlooking the neuropeptide’s potential effects on an infant’s brain and behavior. This new study shows “the other half of the equation to what we already knew,” says Zoe Donaldson, associate professor of behavioral neuroscience at the University of Colorado Boulder, who was not involved with the study. Oxytocin is “this social signal that ultimately reinforces relationships,” she says. The work employed a novel optogenetic tool that enabled the team to turn off neurons deep in the hypothalamus of mouse pups. After being separated from their mothers for three hours, the pups vocalized more using distinct patterns when reunited with their mothers than did pups that had not been separated, a process controlled by oxytocin neurons in the pups’ hypothalamus, the team found. “It would make sense if oxytocin is on both sides of this: making moms want to take care of their pups that are calling, and making pups call in a manner that makes mom want to take care of them,” Donaldson says. “Then we have this sort of convergence where oxytocin is once again doing everything.” © 2025 Simons Foundation

Keyword: Sexual Behavior; Animal Communication
Link ID: 29928 - Posted: 09.13.2025

By Holly Barker Prairie voles do not need oxytocin receptors to bond with a mate or care for their pups, but the receptors are indispensable for forming robust friendships, according to a study published today in Current Biology. Female voles that lack the receptors struggle to make friends with other females, and when they do, they are not motivated to spend time with friends over strangers and quickly lose track of their friends in a group, the study found. The findings suggest that oxytocin is required for nurturing specific relationships, rather than for general sociability, says principal investigator Annaliese Beery, associate professor of integrative biology and neuroscience at the University of California, Berkeley. That concept—known as selectivity—is a “really important component of human friendships,” she says. Until now, prairie voles have typically been used to probe the neural basis of love: The animals are unusual among rodents for selecting a single partner to nest and raise pups with. Compared with non-monogamous vole species, prairie voles have a high density of oxytocin receptors in multiple brain regions, including the nucleus accumbens. Drugs that block the receptors there impair mate attachment in prairie voles, whereas brain infusions of oxytocin fast track the animal’s choice of a lifelong partner. Oxytocin appears to be especially important in the initial stages of bond formation, according to studies of transgenic prairie voles. Voles genetically engineered to carry loss-of-function mutations in both copies of the oxytocin receptor gene are less likely to bond with a littermate they have been housed with for less than a week, according to work reported in a 2024 preprint. © 2025 Simons Foundation

Keyword: Hormones & Behavior; Evolution
Link ID: 29883 - Posted: 08.09.2025

By Shaena Montanari Leafcutter ants’ roles can be reprogrammed by manipulating two neuropeptides, according to a new study. These ants are known for their rigorous division of labor in a caste system, with groups performing roles ranging from cutting leaves to nest defense to tending the fungus that is their food source. Despite physical differences among the ants—the heads of the nest defender ants can be five times the size of the fungal carers’ heads, for instance—it’s still possible to “pharmacologically reprogram them to assume some of the roles that typically other castes assume,” indicating behavioral flexibility, says Daniel Kronauer, professor at Rockefeller University, who was not involved in the work. The researchers induced the behavioral changes by first using RNA sequencing to uncover target neuropeptides and then manipulating neuropeptide levels in the ants. The study was published in June in Cell. The work illustrates the close relationship between neuropeptides and behavior, says Shelley Berger, professor of cell and developmental biology at the University of Pennsylvania and principal investigator of the study. Defender ants are “so big and awkward and clumsy,” she says, but after a certain neuropeptide level is lowered, the ant becomes a “nurse tending to the brood.” The study shows the “importance of neuropeptides as these molecular controllers of incredibly complex” behavioral traits, says Zoe Donaldson, professor of behavioral neuroscience at the University of Colorado Boulder, who was not involved in the study. “I think it’s a really elegant demonstration of just how powerful they are.” Almost all species of ants live in colonies, but leafcutter ants (Atta cephalotes) have a particularly intricate labor division, says study investigator Karl Glastad, assistant professor of biology at the University of Rochester. He and Berger previously explored hormonal controls of social behavior in Florida carpenter ants, which have two worker subtypes, but leafcutter ants are a “really elaborated version” of that species, Glastad says. © 2025 Simons Foundation

Keyword: Hormones & Behavior; Evolution
Link ID: 29856 - Posted: 07.16.2025

By Rachel E. Gross Estrogen is the Meryl Streep of hormones, its versatility renowned among scientists. Besides playing a key role in sexual and reproductive health, it strengthens bones, keeps skin supple, regulates sugar levels, increases blood flow, lowers inflammation and supports the central nervous system. “You name the organ, and it promotes the health of that organ,” said Roberta Brinton, a neuroscientist who leads the Center for Innovation in Brain Science at the University of Arizona. But appreciation for estrogen’s more expansive role has been slow in coming. The compound was first identified in 1923 and was henceforth known as the “female sex hormone” — a one-dimensional reputation baked into its very name. “Estrogen” comes from the Greek “oestrus,” a literal gadfly known for whipping cattle into a mad frenzy. Scientifically, estrus has come to mean the period in the reproductive cycles of some mammals when females are fertile and sexually active. Women don’t enter estrus; they menstruate. Nevertheless, when researchers named estrogen, these were the roles it was cast in: inducing a frenzy and supporting female sexual health. Now, estrogen is gaining recognition for what may be its most important role yet: influencing the brain. Neuroscientists have learned that estrogen is vital to healthy brain development but that it also contributes to conditions including multiple sclerosis and Alzheimer’s. Changes in estrogen levels — either from the menstrual cycle or external sources — can exacerbate migraines, seizures and other common neurological symptoms. “There are a huge number of neurological diseases that can be affected by sex hormone fluctuations,” said Dr. Hyman Schipper, a neurologist at McGill University who listed a dozen of them in a recent review in the journal Brain Medicine. “And many of the therapies that are used in reproductive medicine should be repurposed for these neurological diseases.” Today, the insight that sex hormones are also brain hormones is transforming how doctors approach brain health and disease — helping them guide treatment, avoid harmful interactions and develop new hormone-based therapies.. © 2025 The New York Times Company

Keyword: Hormones & Behavior; Sexual Behavior
Link ID: 29757 - Posted: 04.23.2025

By Shaena Montanari Just as romantic partners exhibit more similar brain waves than do strangers when, say, drawing on an Etch A Sketch toy together, animal pairs also show neural synchrony during social interactions and cooperation tasks. “Neural synchrony is something that happens in these minute-to-minute engagements that you have with another individual,” says Zoe Donaldson, associate professor of behavioral neuroscience at the University of Colorado Boulder. But over time, too, pairs in a relationship learn to infer what their partner is going to do, she adds. In prairie voles, at least, that learning process may unfold at the molecular level in the form of “transcriptional synchrony,” according to a preprint Donaldson and her colleagues posted on bioRxiv in November. Prairie voles are socially monogamous, and after two of them bond, gene-expression patterns in their nucleus accumbens—a forebrain region linked to reward and social interaction—start to align. It remains unclear whether this transcriptional synchrony causes pair bonding or only correlates with it, she adds, but in the meantime, it offers researchers a new place to hunt for the basis of these strong social ties. This new study “pushes the limits of what’s possible” technically, says Robert Froemke, professor in New York University’s Neuroscience Institute and otolaryngology department, who was not involved in the study. Though the existence of neural synchrony logically suggests that there may also be shared patterns of gene expression, “it’s still remarkable to actually have it documented,” he says. The new preprint offers the first evidence of transcriptional synchrony in prairie voles, Donaldson says, but a 2020 study revealed that fighting pairs of Betta splendens fish show a strong correlation of gene expression after 60 minutes of fighting, and only a weak correlation after 20 minutes. © 2025 Simons Foundation

Keyword: Sexual Behavior
Link ID: 29630 - Posted: 01.15.2025

By Laura Sanders Pregnancy overhauls a woman’s body. The brain is no exception. A detailed study of a woman’s brain before, during and after pregnancy revealed sweeping neural changes, some of which stuck around months after her baby was born. The dataset, published September 16 in Nature Neuroscience, is the first comprehensive view of the neural changes that accompany gestation — a sort of “what to expect when you’re expecting” for the brain. “The results of this case study are astonishing,” says neuroscientist Clare McCormack of New York University Langone Health. “Here we see, for the first time in humans, the extent of brain changes that are under way throughout pregnancy.” This research joins a small number of other studies aimed at understanding the female brain at various stages of life (SN: 9/29/22). Collectively, the work suggests that the process of becoming a mother, called matrescence, is another stage of development, like the brain overhaul that happens in adolescence (SN: 2/27/23). Earlier experiments mostly compared brains of women before and after their pregnancies and inferred what happens in between (SN: 12/19/16). “There was a missing piece,” McCormack says. “The nine months of pregnancy was a black box, and we could only guess what that trajectory looks like.” With four MRI scans before pregnancy, 15 scans during pregnancy and seven scans in the two years after the baby was born, the new study follows the entire arc for one mother. © Society for Science & the Public 2000–2024.

Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 29485 - Posted: 09.18.2024

By Erin Garcia de Jesús An appetite-stimulating protein can reverse anorexia in mice. Mice with lack of appetite and weight loss — symptoms similar to people with anorexia — that were genetically tweaked to secrete a protein called ACBP ate more food and weighed more than anorexic animals with an ACBP deficit, researchers report August 14 in Science Translational Medicine. The finding points to a potential treatment target for people with the eating disorder. “Anorexia is a whole brain and body illness” that is difficult to treat, says psychiatrist and neuroscientist Rachel Ross, who wasn’t involved with the new work. “One of the major challenges is that the brain of a person with anorexia is directly fighting against their body.” While the body screams for food, the brain prioritizes the need to restrict weight (SN: 7/26/13). Globally, around 1 percent of women and 0.2 percent of men develop the disorder. Roughly just a third of those people fully recover. Yet, no drugs are available; treatment typically involves medical care to stabilize weight and therapy to mend patients’ relationships with food. Some cancer patients can also develop a similar disorder called cancer cachexia, which comes from an impaired metabolism, that is similarly tough to treat (SN: 7/30/24). “Anything that has the potential to provide some sort of mechanism that would be useful for creating a new therapeutic is huge,” says Ross, of Albert Einstein College of Medicine and Montefiore Health System in New York City. And although there’s no guarantee the results will apply to people, the new findings suggest that ACBP, a protein that helps turn on parts of the brain that arouse appetite, may have that potential. © Society for Science & the Public 2000–2024.

Keyword: Obesity; Hormones & Behavior
Link ID: 29435 - Posted: 08.15.2024

By Lauren J. Young Kimberly Chauche, a corporate secretary in Lincoln, Neb., says she’s always been overweight. When she was as young as five years old, her doctors started trying to figure out why. Since then her life has involved nutritionists and personal trainers, and eventually she sought therapists to treat her compulsive eating and weight-related anxiety. Yet answers never arrived, and solutions never lasted. At 43, Chauche was prescribed a weight-loss medi­cation called Wegovy—one of a new class of drugs that mimic a hormone responsible for insulin pro­duction. She took her first dose in March 2024, in­jecting it into herself with a needle. Within a couple of months she had lost almost 20 pounds, and that felt great. But the weight loss seemed like a bonus com­pared with a startling change in how she reacted to food. She noticed the shift almost immediately: One day her son was eating popcorn, a snack she could never resist, and she walked right past the bowl. “All of a sudden it was like some part of my brain that was always there just went quiet,” she says. Her eating habits improved, and her anxiety eased. “It felt almost surreal to put an injector against my leg and have happen in 48 hours what decades of intervention could not ac­complish,” she says. “If I had lost almost no weight, just to have my brain working the way it’s working, I would stay on this medication forever.” Chauche is hardly alone in her effusive descriptions of how Wegovy vanquished her intrusive thoughts about food—an experience increasingly referred to as the “quieting of food noise.” Researchers—some of whom ushered in the development of these blockbuster drugs—want to understand why. Among them is biochemist Svetlana Mojsov of the Rockefeller University, who has spent about 50 years investigating gut hormones that could be key to regulating blood glucose levels. In seeking potential treatments for type 2 diabetes, Mojsov ultimately focused on one hormone: glucagonlike peptide 1, or GLP-1. Her sequence of the protein in the 1980s became the initial template for drugs like Wegovy. The medications, called GLP-1 receptor agonists, use a synthetic version of the natural substance to activate the hormone’s receptors. The first ones arrived in 2005. In 2017 the U.S. Food and Drug Administration approved semaglutide—now widely known as Ozempic. © 2024 SCIENTIFIC AMERICAN,

Keyword: Obesity; Hormones & Behavior
Link ID: 29373 - Posted: 06.26.2024

By Meghan Rosen An experimental weight loss procedure cranks up the heat to dial down hunger. Blasting a patch of patients’ stomach lining with thermal energy curbed hunger and cut pounds, researchers reported in a small pilot study to be presented at the annual Digestive Disease Week meeting on May 19 in Washington, D.C. Called gastric fundus mucosal ablation, the procedure relies on an endoscope, a thin tube that can be threaded down the throat. It takes less than an hour and doesn’t require hospitalization. “The advantage of this is that it’s a relatively straightforward procedure,” says Cleveland Clinic surgical endoscopist Matthew Kroh, who was not involved with the work. Side effects, which included mild nausea and cramping, are minimal, one study author said in a news conference on May 8. That’s a big difference from bariatric surgery, considered the gold standard treatment for obesity, which includes many techniques to restrict stomach size or affect food absorption. Patients can be hospitalized for days and take weeks to recover. Obese people often avoid these treatments because they don’t want to endure surgery, Kroh says. The new procedure could one day offer an easier option — if the results hold up in larger groups of patients. “There’s potential,” Kroh says, “but I think we have to be cautious.” The trial included 10 women, so the method is still at the proof-of-concept stage. On average, the women lost nearly 8 percent of their body weight, some 19 pounds, over six months. That’s less than patients typically see from bariatric surgery or pharmaceutical treatments like the anti-obesity drug Wegovy (SN 12/13/23). © Society for Science & the Public 2000–2024.

Keyword: Obesity; Hormones & Behavior
Link ID: 29311 - Posted: 05.18.2024

By Michael S. Rosenwald Prairie voles are stocky rodents and Olympian tunnellers that surface in grassy areas to feast on grass, roots and seeds with their chisel-shaped teeth, sprouting migraines in farmers and gardeners. But to Larry Young, they were the secret to understanding romance and love. Professor Young, a neuroscientist at Emory University in Atlanta, used prairie voles in a series of experiments that revealed the chemical process for the pirouette of heart-fluttering emotions that poets have tried to put into words for centuries. He died on March 21 in Tsukuba, Japan, where he was helping to organize a scientific conference. He was 56. The cause was a heart attack, his wife, Anne Murphy, said. With their beady eyes, thick tails and sharp claws, prairie voles are not exactly cuddly. But among rodents, they are uniquely domestic: They are monogamous, and the males and females form a family unit to raise their offspring together. “Prairie voles, if you take away their partner, they show behavior similar to depression,” Professor Young told The Atlanta-Journal Constitution in 2009. “It’s almost as if there’s withdrawal from their partner.” That made them ideal for laboratory studies examining the chemistry of love. In a study published in 1999, Professor Young and his colleagues exploited the gene in prairie voles associated with the signaling of vasopressin, a hormone that modulates social behavior. They boosted vasopressin signaling in mice, which are highly promiscuous. Headline writers were amused. “Gene Swap Turns Lecherous Mice Into Devoted Mates,” The Ottawa Citizen declared. The Fort Worth Star-Telegram: “Genetic Science Makes Mice More Romantic.” The Independent in London: “‘Perfect Husband’ Gene Discovered.” © 2024 The New York Times Company

Keyword: Hormones & Behavior; Sexual Behavior
Link ID: 29288 - Posted: 05.03.2024

By Angie Voyles Askham Larry Young, a neuroscientist known for illuminating oxytocin’s outsized role in social bonding, died of a heart attack last month at the age of 57. In his 30-year career at Emory University, Young teased apart the neurobiology of love and relationships—from the receptors that make voles monogamous to the hormones that shape sociability in psychiatric disorders. He founded and directed both the Center for Translational Social Neuroscience and the Silvio O. Conte Center for Oxytocin and Social Cognition at Emory, and he helped establish the Laboratory of Social Neural Networks in Tsukuba, Japan. “His impact has been enormous,” says Steven Phelps, professor of integrative biology at the University of Texas at Austin, who was Young’s first postdoctoral researcher at Emory. “He brought molecular biology to what we would call non-model organisms, the species that are normally neglected by mainstream science.” Young also fostered collaborations through the many international conferences he organized, and he raised the public profile of neuroscience research through his dedication to science communication. He served as a hub within the field of social neuroscience—someone who connected others across continents and research modalities—says Steve Chang, associate professor of psychology and neuroscience at Yale University. “Everyone feels there is now a giant hole.” Young grew up on a farm in Sylvester, Georgia, a small town that claims the title of “Peanut Capital of the World.” As a child, he loved animals and kept many pets—including, for a time, a possum that he carried around on his head, Young recalled on a podcast in 2022. He had thoughts of becoming a veterinarian but pivoted to medicine when, in his biochemistry classes at the University of Georgia, he became fascinated with genetics and how nature manages to translate a string of letters to the behaviors necessary for survival. © 2024 Simons Foundation

Keyword: Hormones & Behavior; Sexual Behavior
Link ID: 29257 - Posted: 04.16.2024

Jon Hamilton A sibling can change your life — even before you're born. That's because when males and females share a womb, sex hormones from one fetus can cause lasting changes in the others. It's called the intrauterine position phenomenon, or intrauterine position effects, and different versions of it have been observed in rodents, pigs, sheep — and, probably, humans. "It's really kind of strange to think something so random as who you develop next to in utero can absolutely change the trajectory of your development," says Bryce Ryan, a professor of biology at the University of Redlands. The phenomenon is more than a scientific oddity. It helped establish that even tiny amounts of hormone-like chemicals, like those found in some plastics, could affect a fetus. Cattle breeders in ancient Rome may have been the first people to recognize the importance of a sibling's sex. They realized that when a cow gives birth to male-female twins, the female is usually sterile. These females, known as freemartins, also act more like males when they grow up. Scientists began to understand why in the early 1900s. They found evidence that hormones from the male twin were affecting the female's development. The effect is less obvious in other mammals, Ryan says. Female offspring in rodents, for example, can still reproduce, but they have measurable differences in sexual development and tend to be more aggressive. © 2024 npr

Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 29250 - Posted: 04.11.2024

By Catherine Offord Bone marrow transplants between mice can transmit symptoms and pathology associated with Alzheimer’s disease, according to a controversial study published today in Stem Cell Reports. Its authors found that healthy mice injected with marrow from a mouse strain carrying an extremely rare, Alzheimer’s-linked genetic mutation later developed cognitive problems and abnormal clumping of proteins in the brain. In claims that other scientists in the field have criticized as overstated, the team says its findings demonstrate “Alzheimer’s disease transmission” and support screening of human bone marrow, organ, and blood donors for mutations related to neurodegeneration. “The findings are not by any means conclusive,” says Lary Walker, a neuroscientist at Emory University. Although the team’s approach offers an interesting way to study potential causes of neurodegeneration, he says, “the mice do not have Alzheimer’s disease,” only certain symptoms that mimic those of the disorder and require further study. He and other scientists stress that the new findings should not deter people who medically need bone marrow or other transplants. Alzheimer’s is partly characterized by so-called plaques of beta amyloid, a fragment of a larger protein called APP, around cells in the brain. Although there are rare, early-onset versions of the disease driven by specific mutations in the gene coding for APP or related proteins, most cases arise in people over age 65 and don’t have a single known cause. Some research hints that in very unusual scenarios, Alzheimer’s could be transmitted via human tissue or medical equipment contaminated with disease-causing proteins. Earlier this year, for example, U.K. scientists described dementia and beta amyloid buildup in several people who had received injections of growth hormone from the brains of deceased donors. (The procedure was once a medical treatment for certain childhood disorders but was abandoned in the 1980s.)

Keyword: Alzheimers; Hormones & Behavior
Link ID: 29225 - Posted: 03.30.2024

By Gina Jiménez Being pregnant and giving birth changes a person’s brain, but the brain looks different depending on whether it’s examined during pregnancy or after a person gives birth, a recent study found. The research is helping disentangle some of the mysteries in the long-ignored field of maternal neuroscience. The study, published in January in Nature Neuroscience, followed more than 100 new mothers from near the end of their pregnancy until about three weeks on average after they had their baby. Previous research had examined birthing parents’ brain before they gave birth or during the postpartum period, but this study observed them both before and after birth, and it also took into account whether they had a vaginal birth or C-section. The findings reveal temporary changes in some brain regions and more permanent ones in a brain circuit that activates when people are not engaged in an active task and that is also involved in self-reflection and empathizing with others. The study has “ordered” some of the scientific disagreements in the field, says its senior author Susana Carmona, a neuroscience researcher now at Gregorio Marañón General University Hospital in Spain.* “It fills important gaps—that is why it’s novel,” says Joe Lonstein, a neuroscientist who studies animal parenting behaviors at Michigan State University but was not involved with the new paper. “There were things we just didn’t know about the timing of events.” Much of the scientific literature on pregnancy and postpartum neuroscience is only around a decade old. A 2016 study found that gray matter decreased in women after they had a baby for the first time, and the reductions persisted for at least six years after pregnancy. In contrast, other studies have observed that gray matter increases in the first weeks after people give birth. The new paper helps reconcile these results: the researchers found that women indeed lost gray matter during pregnancy and childbirth but got it back in most brain areas after they had their baby. © 2024 SCIENTIFIC AMERICAN,

Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 29197 - Posted: 03.19.2024

Ian Sample Science editor Human tears carry a substance that dampens down aggression, according to researchers, who believe the drops may have evolved over time to protect wailing babies from harm. Sniffing emotional tears from women reduced male aggression by more than 40% in computerised tests, and prompted corresponding changes in the brain, though the scientists behind the study think all human tears would have a similar effect. “The reduction in aggression was impressive to us, it seems real,” said Noam Sobel, a professor of neurobiology at the Weizmann Institute of Science in Israel. “Whatever is in tears actually lowers aggression.” Charles Darwin puzzled over the point of weeping. Writing in The Expression of Emotions in Man and Animals in 1872, the great naturalist declared sobbing as “purposeless as the secretion of tears from a blow outside the eye”. But in the 150 years since, researchers have proposed all manner of roles, from signalling vulnerability and helplessness to clearing bacteria from the eyes. Previous work at Sobel’s lab found that sniffing women’s tears reduced male testosterone but it was unclear whether this affected behaviour. In animals, the picture is clearer: subordinate mole rats, for example, cover themselves in tears to protect themselves from aggressors. For the latest study, Dr Shani Agron and others in Sobel’s lab collected tears rolling down women’s faces as they watched sad movies. The researchers did not specifically advertise for female tear donors but nearly all who came forward were women, of whom six were selected because they produced tears in such quantities. The experiments involved 31 men who sniffed either saline or women’s tears before having swabs dabbed with the droplets stuck to their upper lip. The men then took part in a computerised game used in psychology to provoke aggressive behaviour by unfairly deducting players’ points. © 2023 Guardian News & Media Limited

Keyword: Aggression; Chemical Senses (Smell & Taste)
Link ID: 29063 - Posted: 12.22.2023

Maria Godoy What do you do when you can't get your kids to settle down to go to sleep? For a growing number of parents, the answer is melatonin. Recent research shows nearly one in five school-age children and adolescents are now using the supplement on a regular basis. Pediatricians say that's cause for alarm. "It is terrifying to me that this amount of an unregulated product is being utilized," says Dr. Cora Collette Breuner, a professor of pediatrics at the University of Washington. Melatonin is a hormone produced by your brain that helps regulate sleep-wake cycles. It's also sold as a dietary supplement and is widely used as a sleep aid. Sponsor Message Lauren Hartstein, a postdoctoral researcher who studies sleep in early childhood at the University of Colorado, Boulder, says she first got an inkling of melatonin's growing use in children and adolescents while screening families to participate in research. "All of a sudden last year, we noticed that there was a big uptick in the number of parents who were regularly giving [their kids] melatonin," Hartstein says. Hartstein and her colleagues wanted to learn more about just how widely melatonin is being used in kids. So they surveyed the parents of nearly 1,000 children between the ages of 1 to 14 across the country. She was surprised by just how many kids are taking the supplement. "Nearly 6% of preschoolers, [ages] 1 to 4, had taken it, and that number jumped significantly higher to 18% and 19% for school-age children and pre-teens," she says. As Hartstein and her co-authors recently reported in the journal JAMA Pediatrics, most of the kids that were using melatonin had been on it for a year or longer. And 1 in 4 kids were taking it every single night. © 2023 npr

Keyword: Biological Rhythms; Sleep
Link ID: 29047 - Posted: 12.16.2023

By Meeri Kim A woman’s menstrual cycle is driven by the ebb and flow of hormones that prepare the body for pregnancy. This symphony of hormones not only transforms the reproductive organs, but, according to recent research, also reshapes the brain. Live well every day with tips and guidance on food, fitness and mental health, delivered to your inbox every Thursday. Two studies released in October performed detailed brain scans of women at multiple points across the menstrual cycle, finding that the volume or thickness of certain regions change in sync with hormone levels. The areas of the brain highlighted by both studies are those in the limbic system, a group of brain structures that govern emotions, memory and behavior. “It’s like the brain being on a roller coaster every 28 days or so, depending on the length of the cycle,” said Erika Comasco, associate professor of women and children’s health at Uppsala University in Sweden, who was not involved in the research. “The importance of these studies is that they are building knowledge about the impact of these hormonal fluctuations on how the brain is structured.” “These brain changes may or may not alter the way we actually act, think and feel in our everyday lives. So the important next steps for the science are to put those pieces of the puzzle together,” said Adriene Beltz, associate professor of psychology at the University of Michigan, who was also not involved in the research. “Do the hormonal effects on brain structure influence how the brain works?” How hormones drive the menstrual cycle During a woman’s period, which marks the beginning of the menstrual cycle, hormones are at low levels. But they rise dramatically over a few weeks. Estrogen levels in the blood become eight times higher at ovulation around Day 14, while progesterone levels increase by 80-fold approximately seven days later. The production of follicle-stimulating hormone prompts the growth of an ovarian follicle into a mature egg, while a surge of luteinizing hormone triggers the release of the egg.

Keyword: Hormones & Behavior; Sexual Behavior
Link ID: 29026 - Posted: 12.02.2023

Claudia López Lloreda The idea that the nervous system passes messages from one nerve cell to another only through synapses — the points where the cells link up end to end — is changing. Two studies show how messages can pass between cells over longer distances, through a ‘wireless’ nerve network in the worm Caenorhabditis elegans. Researchers had not appreciated the extent of this wireless communication, which happens when a molecule called a neuropeptide is released by one neuron and intercepted by another some distance away. The new studies, published in Nature1 and in Neuron2, map out the entire network of neuropeptide communication in a model organism for the first time. “We knew that these chemical connections existed, but this is probably the most comprehensive study in an entire nervous system,” says Gáspár Jékely, a neuroscientist at Heidelberg University in Germany who was not involved in the work. And what the research shows, he adds, is that “it’s not all about the synapses”. Researchers had previously worked out anatomical wiring maps — connectomes — showing how all the neurons in the fruit fly (Drosophila melanogaster) and in C. elegans are linked by their synapses. However, William Schafer, a neuroscientist at the MRC Laboratory of Molecular Biology in Cambridge, UK, wondered about the role of neuropeptides, which had been considered merely helpers in nervous-system messaging. “When I first started talking about this,” he says, “some people wondered, ‘is it all just kind of a soup’” where neuropeptides randomly float from one neuron to the next, “or can you really think about it like a network?” He and his colleagues analysed which neurons in the C. elegans nervous system expressed genes for certain neuropeptides and which ones expressed genes for the receptors of those neuropeptides. Using this data, the team predicted which pairs of nerve cells might be communicating wirelessly. On the basis of these results, the researchers generated a potential map of wireless connections in the worm, finding dense connectivity that looks very different from the anatomical wiring diagram of C. elegans. They published their findings in Neuron2 last week. © 2023 Springer Nature Limited

Keyword: Hormones & Behavior
Link ID: 29017 - Posted: 11.22.2023

By Sandra G. Boodman Bridget Houser felt despairing. In the months before her 2018 wedding, Houser, who had never struggled with her weight, noticed that it inexplicably began to creep up. In response she doubled the length of her runs to eight miles, took back-to-back high intensity workout classes and often consumed only water, coffee and fruit during the day before a spartan, mostly vegetable, dinner. Yet no matter what Houser did, her weight stubbornly increased and her oval face grew round, a transformation that was glaringly obvious in comparison with her identical twin sister. Houser wondered whether the five pounds she gained despite her herculean effort was a corollary of other problems. For the previous two years she had battled a string of maladies: first daily headaches, then crippling anxiety, followed by insomnia, hair loss and acne, something she’d never endured as a teenager. “Stress was the universal explanation,” recalled Houser, a controller for a small business in Chicago. When doctors suggested that her upcoming marriage might be a cause of her problems, Houser considered, then rejected, the theory. It just didn’t jibe with her feelings. In early 2019, about six months after her wedding, Houser insisted that her doctors perform several tests. They ultimately revealed that her symptoms weren’t the result of stress or marital misgivings but of a serious illness that had been smoldering for years. After successful treatment followed by a long recovery Houser, now 34, feels far better than she did during those miserable years in her late 20s. “I wish I’d been nicer to myself and not blamed myself for what was going on,” she said.

Keyword: Hormones & Behavior
Link ID: 28951 - Posted: 10.10.2023