Links for Keyword: Sexual Behavior

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By Elizabeth Pennisi Males resort to all sorts of desperate measures when fertile females are scarce, including banding together to guard a potential mate. Now, researchers have discovered that such bands of bottlenose dolphins may coordinate their actions with unique “popping” calls—the first evidence that animals other than humans can synchronize themselves using vocal signals. Humans often use vocal signals to coordinate actions, like marching and dancing, that reinforce unity and intimidate outside groups. The synchronized displays of other animals—like fireflies that light up at the same time—are thought to be competitive, showing off which male is the sexiest, rather than cooperative. In Shark Bay, off the coast Western Australia 800 kilometers north of Perth, groups of up to 14 male dolphins form lifelong alliances. Together, subsets of three keep close tabs on potential female mates, swimming, turning, and surfacing in unison to guard and herd them—one female at a time. Scientists watching this behavior noticed these males often emit a unique “popping” call, making series of two to 49 very short sounds, 10 per second, over and over. e dolphins popping The scientists dragged four underwater microphones behind a motorboat and recorded 172 instances in which multiple males were “popping” together (above). When the males pop alone, their timing and tempo varies. But when they pop together, they do it at the same time and at the same rate, suggesting they are using the sounds to enhance their cooperation, the team reports today in the Proceedings of the Royal Society B. This synchronized popping may be a threat, as it tends to make the female dolphin move closer to her male guards. But more importantly, the researchers say, it may help reinforce that the males need to act—and talk—as one to ensure they get their gal. © 2020 American Association for the Advancement of Science

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 11: Emotions, Aggression, and Stress
Link ID: 27156 - Posted: 04.01.2020

By Matt McGrath Environment correspondent A new study that looks at lifespan in wild mammals shows that females live substantially longer than males. The research finds that, on average, females live 18.6% longer than males from the same species. This is much larger than the well-studied difference between men and women, which is around 8%. The scientists say the differences in these other mammals are due to a combination of sex-specific traits and local environmental factors. In every human population, women live longer than men, so much so that nine out of 10 people who live to be 110 years old are female. This pattern, researchers say, has been consistent since the first accurate birth records became available in the 18th Century. While the same assumption has been held about animal species, large-scale data on mammals in the wild has been lacking, Now, an international team of researchers has examined age-specific mortality estimates for a widely diverse group of 101 species. In 60% of the analysed populations, the scientists found that females outlived the males - on average, they had a lifespan that's 18.6% longer than males. "The magnitude of lifespan and ageing across species is probably an interaction between environmental conditions and sex-specific genetic variations," said lead author Dr Jean-Francois Lemaître, from the University of Lyon, France. He gives the example of bighorn sheep for which the researchers had access to good data on different populations. Where natural resources were consistently available there was little difference in lifespan. However, in one location where winters were particularly severe, the males lived much shorter lives. © 2020 BBC.

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 27137 - Posted: 03.24.2020

By Inés Gutiérrez, Rodrigo Pérez Ortega Earlier this month, Mexico’s leading university, the National Autonomous University of Mexico (UNAM), announced that renowned neuroscientist Ranulfo Romo Trujillo would leave his position after being disciplined for an unspecified offense. According to a 4 March press release from UNAM, Romo Trujillo voluntarily asked to be separated from his job at UNAM’s University City campus in Mexico City. Sources close to the case say he had been temporarily suspended because a female worker made a formal complaint of sexual harassment against him following an incident in January. But current and former UNAM students and staff say that reports of inappropriate behavior by Romo Trujillo had circulated for years before his departure. Romo Trujillo, who works at UNAM’s Institute of Cellular Physiology (IFC), did not respond to repeated requests for comment. He is arguably the most famous neuroscientist in Mexico, studying perception, working memory, and decision-making. He has more than 150 publications, including in top journals such as Science and Nature; is on the editorial board of Neuron and other journals; and is one of 11 Mexican members of the U.S. National Academy of Sciences. IFC physiologist Marcia Hiriart Urdanivia acknowledged in an email to Science that, while director of IFC from 2009 to 2017, she received multiple accounts of sexual harassment or inappropriate conduct by Romo Trujillo. Hiriart Urdanivia says she warned Romo Trujillo that “his career was endangered by such actions.” But the women involved did not choose to file official complaints, she says. As a result, “I had no authority to do anything else.” © 2020 American Association for the Advancement of Science.

Related chapters from BN: Chapter 1: Introduction: Scope and Outlook; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 20: ; Chapter 8: Hormones and Sex
Link ID: 27129 - Posted: 03.21.2020

Nicola Davis From humans to black-tailed prairie dogs, female mammals often outlive males – but for birds, the reverse is true. Now researchers say they have cracked the mystery, revealing that having two copies of the same sex chromosome is associated with having a longer lifespan, suggesting the second copy offers a protective effect. “These findings are a crucial step in uncovering the underlying mechanisms affecting longevity, which could point to pathways for extending life,” the authors write. “We can only hope that more answers are found in our lifetime.” The idea that a second copy of the same sex chromosome is protective has been around for a while, supported by the observation that in mammals – where females have two of the same sex chromosomes – males tend to have shorter lifespans. In birds, males live longer on average and have two Z chromosomes, while females have one Z and one W chromosome. Scientists say they have found the trend is widespread. Writing in the journal Biology Letters, the team report that they gathered data on sex chromosomes and lifespan across 229 animal species, from insects to fish and mammals. Hermaphroditic species and those whose sex is influenced by environmental conditions – such as green turtles – were not included. The results reveal that individuals with two of the same sex chromosomes live 17.6% longer, on average, than those with either two different sex chromosomes or just one sex chromosome. The team say the findings back a theory known as the “unguarded X hypothesis”. In human cells, sex chromosome combinations are generally either XY (male) or XX (female). In females only one X chromosome is activated at random in each cell. © 2020 Guardian News & Media Limited

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 27090 - Posted: 03.04.2020

By Shola Lawal These are tough times for fireflies. Like a lot of other insects, they face increasing threats from habitat loss, pesticides and pollution. But they also have a problem that’s unique to luminous bugs: It’s getting harder for them to reproduce because light pollution is outshining their mating signals. Fireflies, it turns out, use their special glowing powers in courtship: Males light up to signal availability and females respond with patterned flashes to show that they’re in the mood. But bright light from billboards, streetlights and houses is interfering and blocking potential firefly couples from pairing up. The problem can reach far from big cities: Bright light gets diffused in the atmosphere and can be reflected into the wilderness. In addition to messing with mating signals, it also disrupts the feeding patterns of the females of some species that glow to attract and eat males. The finding was part of a study published Monday in the journal BioScience. The study, by researchers at Tufts University and the International Union for Conservation of Nature, warned that fireflies could eventually face extinction globally because of multiple threats, including light pollution and habitat loss and habitat degradation from insecticides and chemical pollution. Many insects are affected by habitat loss, but fireflies have it particularly bad, said Sara M. Lewis, a biology professor at Tufts and the lead researcher on the study. “Some fireflies get hit especially hard when their habitat disappears because they need special conditions to complete their life cycle,” she said. Fireflies are a type of beetle. There are more than 2,000 species of them, found mainly in wetlands. But mangrove forests and marshes around the world are increasingly vanishing to make way for cash crops like palm oil, according to the new study. © 2020 The New York Times Company

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 10: Biological Rhythms and Sleep
Link ID: 27018 - Posted: 02.04.2020

Nicola Slawson When Lynn Enright had a hysteroscopy to examine the inside of the womb, her searing pain was dismissed by medical professionals. She only understood why when she started working on her book on female anatomy, Vagina: A Re-education. She was looking for research on pain and women’s health, only to be shocked by how little data she found. It wasn’t just the topic of pain that was poorly researched. The lack of evidence was a problem she encountered time and time again, which is no surprise when you look at the research gap: less than 2.5% of publicly funded research is dedicated solely to reproductive health, despite the fact that one in three women in the UK will suffer from a reproductive or gynaecological health problem. There is five times more research into erectile dysfunction, which affects 19% of men, than into premenstrual syndrome, which affects 90% of women. “Women have been woefully neglected in studies on pain. Most of our understanding of ailments comes from the perspective of men; it is overwhelmingly based on studies of men, carried out by men,” Enright says. Her book is one of several in the past year about the female body and the impact a lack of knowledge can have on diagnosis and treatment. They include Emma Barnett’s Period, Eleanor Morgan’s Hormonal, and Gabrielle Jackson’s Pain and Prejudice, which draws on her experience of being diagnosed with endometriosis, a chronically underfunded condition. Given that in the US, which produces a lot of medical research, research trials weren’t required by the National Institutes of Health to include women until 1993, the lack of knowledge is perhaps no surprise. Traditionally this was justified by the idea that women’s bodies were seen to be too complex due to fluctuating hormones, so clinical trials often excluded them. © 2019 Guardian News & Media Limited

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 5: Hormones and the Brain
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 8: Hormones and Sex
Link ID: 26898 - Posted: 12.18.2019

By Eva Frederick Many human grandmothers love to spoil their grandchildren with attention and treats, and for good reason: Studies have shown that having a living grandmother increases a child’s chance of survival. Now, new research shows the same may be true for killer whales. By providing young animals with some freshly caught salmon now and then—or perhaps with knowledge on where to find it—grannies increase their grand-offspring’s chance of survival. The new study is the first direct evidence in nonhuman animals of the “grandmother hypothesis.” The idea posits that females of some species live long after they stop reproducing to provide extra care for their grandchildren. “It’s very cool that these long-lived cetaceans have what looks like a postfertile life stage,” says Kristen Hawkes, an anthropologist at the University of Utah in Salt Lake City who has dedicated much of her career to studying the grandmother effect; she was not involved in the new study. Women usually go through menopause between ages 45 and 55, even though they may live to age 80, 90, or older. Studies in modern-day hunter-gatherer communities as well as in populations in Finland and Canada show that older women can help increase the number of children their daughters have, and boost the survival rates of their grandchildren. Dan Franks, a computer scientist and biologist at the University of York in the United Kingdom, wanted to know whether this grandmother effect occurs in other species as well. © 2019 American Association for the Advancement of Science

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 26887 - Posted: 12.10.2019

By James Gorman TEMPE, Ariz. — Xephos is not the author of “Dog Is Love: Why and How Your Dog Loves You,” one of the latest books to plumb the nature of dogs, but she helped inspire it. And as I scratched behind her ears, it was easy to see why. First, she fixed on me with imploring doggy eyes, asking for my attention. Then, every time I stopped scratching she nudged her nose under my hand and flipped it up. I speak a little dog, but the message would have been clear even if I didn’t: Don’t stop. We were in the home office of Clive Wynne, a psychologist at Arizona State University who specializes in dog behavior. He belongs to Xephos, a mixed breed that the Wynne family found in a shelter in 2012. Dr. Wynne’s book is an extended argument about what makes dogs special — not how smart they are, but how friendly they are. Xephos’ shameless and undiscriminating affection affected both his heart and his thinking. As Xephos nose-nudged me again, Dr. Wynne was describing genetic changes that occurred at some point in dog evolution that he says explain why dogs are so sociable with members of other species. “Hey,” Dr. Wynne said to her as she tilted her head to get the maximum payoff from my efforts, “how long have you had these genes?” No one disputes the sociability of dogs. But Dr. Wynne doesn’t agree with the scientific point of view that dogs have a unique ability to understand and communicate with humans. He thinks they have a unique capacity for interspecies love, a word that he has decided to use, throwing aside decades of immersion in scientific jargon. © 2019 The New York Times Company

Related chapters from BN: Chapter 19: Language and Lateralization; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 15: Language and Lateralization; Chapter 8: Hormones and Sex
Link ID: 26848 - Posted: 11.23.2019

Jef Akst From a small inflatable boat in the Rangiroa atoll in French Polynesia, Pamela Carzon got her first glimpse of the “strange” trio of marine mammals she’d been told about: a bottlenose dolphin mother (Tursiops truncatus), her seven-month-old calf, and another young cetacean that was slightly smaller and looked to be not a bottlenose dolphin at all, but a melon-headed whale (Peponocephala electra). It was April 2015, and Carzon and a colleague at the Marine Mammal Study Group of French Polynesia, a nongovernmental organization dedicated to whale and dolphin conservation, were out for the NGO’s annual photo-ID survey, very much hoping to find animals that a former collaborator had seen while diving in the region the previous November. “[T]he sea was very calm, and there were many dolphins around,” Carzon, also a PhD student at the Center for Island Research and Environmental Observatory (CRIOBE) in French Polynesia and the École Pratique des Hautes Études in Paris, recalls in an email to The Scientist. “It took us maybe two minutes to spot them: the dark calf was easy to spot among the bottlenose dolphins.” The mother, dubbed ID#TP25 by the researchers, was known to tolerate divers and boats, and that April day she approached the inflatable with both calves. Carzon grabbed her underwater camera and slipped into the water. “I was able to get good underwater footage and to sex both calves,” she says. ID#TP25’s natural calf was a female; the second calf was male. “I also noticed that both were ‘gently’ pushing each other [in order] to remain under the adult female’s abdomen” in so-called infant position. Continued observation over the following months revealed that the dolphin mom was nursing the foreign calf, whose species ID remains to be confirmed with genetic testing, and otherwise treated him as one of her own. © 1986–2019 The Scientist.

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 26836 - Posted: 11.20.2019

Jon Hamilton There's new evidence that girls start out with the same math abilities as boys. A study of 104 children from ages 3 to 10 found similar patterns of brain activity in boys and girls as they engaged in basic math tasks, researchers reported Friday in the journal Science of Learning. "They are indistinguishable," says Jessica Cantlon, an author of the study and professor of developmental neuroscience at Carnegie Mellon University. The finding challenges the idea that more boys than girls end up in STEM fields (science, technology, engineering, and mathematics) because they are inherently better at the sort of thinking those fields require. It also backs other studies that found similar math abilities in males and females early in life. "The results of this study are not too surprising because typically we don't see sex differences at the ages assessed in this study or for the types of math tasks they did, which were fairly simple," says David Geary, a psychologist and curator's distinguished professor at the University of Missouri who was not involved in the research. But there is evidence of sex differences in some exceptional older students, Geary says. For example, boys outnumber girls by about three to one when researchers identify adolescents who achieve "very, very high-end performance in mathematics," Geary says, adding that scientists are still trying to understand why that gap exists. © 2019 npr

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 17: Learning and Memory
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 13: Memory and Learning
Link ID: 26803 - Posted: 11.08.2019

By Sofie Bates Make some noise for the white bellbirds of the Brazilian Amazon, now the bird species with the loudest known mating call. The birds (Procnias albus) reach about 125 decibels on average at the loudest point in one of their songs, researchers report October 21 in Current Biology. Calls of the previous record-holder — another Amazonian bird called the screaming piha (Lipaugus vociferans) — maxed out around 116 decibels on average. This difference means that bellbirds can generate a soundwave with triple the pressure of that made by pihas, says Jeff Podos, a behavioral ecologist at the University of Massachusetts Amherst, who did the research along with ornithologist Mario Cohn-Haft, of the National Institute of Amazon Research in Manaus, Brazil. The team measured sound intensity from three pihas and eight bellbirds. Each sounded off at different distances from the scientists. So to make an accurate comparison, the researchers used rangefinder binoculars, with lasers to measure distance, to determine how far away each bird was. Then, they calculated how loud the sound would be a meter from each bird to crown a winner. The small white bellbird, which weighs less than 250 grams, appears to be built for creating loud sounds, with thick abdominal muscles and a beak that opens extra wide. “Having this really wide beak helps their anatomy be like a musical instrument,” Podos says. Being the loudest may come with a cost: White bellbirds can’t hold a note for long because they run out of air in their lungs. Their loudest call sounds like two staccato beats of an air horn while the calls of screaming pihas gradually build to the highest point. © Society for Science & the Public 2000–2019

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 19: Language and Lateralization
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 15: Language and Lateralization
Link ID: 26733 - Posted: 10.22.2019

Nicola Davis A possible explanation for one of biology’s greatest mysteries, the female orgasm, has been bolstered by research showing that rabbits given antidepressants release fewer eggs during sex. The human female orgasm has long proved curious, having no obvious purpose besides being pleasurable. The scientists behind the study have previously proposed it might have its evolutionary roots in a reflex linked to the release of eggs during sex – a mechanism that exists today in several animal species, including rabbits. Since humans have spontaneous ovulation, the theory goes that female orgasm may be an evolutionary hangover. They say the new experiment supports the idea. “We know there is a reflex [in rabbits], but the question [is] could this be the same one that has lost the function in humans?” said Dr Mihaela Pavličev a researcher at the University of Cincinnati who co-authored the study. To explore the question the team gave 12 female rabbits a two-week course of fluoxetine (trade name Prozac) – an antidepressant known to reduce the capacity for women to orgasm – and looked at the number of eggs released after the animals had sex with a male rabbit called Frank. The results, published in the Proceedings of the National Academy of Sciences, showed that rabbits given the antidepressants released 30% fewer eggs than nine rabbits that were not given Prozac but still mated with Frank. © 2019 Guardian News & Media Limited

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 26659 - Posted: 10.01.2019

Alison Flood Caroline Criado Perez’s exposé of the gender data gap that has created a world biased against women has won her the Royal Society science book prize. Criado Perez’s Invisible Women, which explores how everything from speech-recognition software to bulletproof vests, from medical tests to office temperature controls are designed for men as a default, was called a brilliant exposé by chair of judges and Oxford professor Nigel Shadbolt. He said the book had made him, as an AI researcher and data scientist, look at his field afresh. “[Criado Perez] writes with energy and style, every page full of facts and data that support her fundamental contention that in a world built for and by men gender data gaps, biases and blind spots are everywhere,” he said. The author and feminist campaigner who successfully pushed for Jane Austen to be featured on the UK’s £10 note, called her £25,000 win on Monday night a huge relief. “Obviously it’s a huge honour, but mainly because it has the official endorsement of scientists and so it can’t be dismissed now, and that’s so important,” she said. “Writing this book was hellish. It really tested my mental strength to its limits, partly because it was a really emotional book to write because of the impact this is having on women’s lives and how angry and upsetting it was to keep coming across this gap in the data. But also it was very challenging because it was a book about the whole world and everything in it, and I had to work out how to synthesise that into something manageable.” © 2019 Guardian News & Media Limited

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 26646 - Posted: 09.25.2019

Daniel Pfau I came out to a Christian counselor during a therapy session in 2001 when I was 14. He convinced me to engage in conversion therapy, a pseudoscientific practice to change an individual’s sexual orientation based in the assumption that such behaviors are “unnatural.” He produced an article describing a talk at that year’s American Psychological Association conference that indicated the therapy worked. This painful experience encouraged me, when I started my scientific career, to examine queerness in biology. The queer community, 25 million years (or more) in the making Understanding how complex human relationships developed requires a complete picture of our social behavior during evolution. I believe leaving out important behaviors, like same-sex sexual behavior, can bias the models we use to explain social evolution. Many researchers have postulated how queer behaviors, like same-sex sexual behavior, may have developed or how they are expressed. Recently, scientists at the Broad Institute of Harvard and MIT published a paper suggesting a genetic component to same-sex sexual behavior expression in modern humans. However, no studies provide an argument of when queer behavior may have arisen during humans’ evolution. Such research would push back against the assertions I encountered during my youth, that queerness is a modern aberration. © 2010–2019, The Conversation US, Inc.

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 26632 - Posted: 09.21.2019

By Kim Tingley Men have a far greater appetite for sex and are more attracted to pornography than women are. This is the timeworn stereotype that science has long reinforced. Alfred Kinsey, America’s first prominent sexologist, published in the late 1940s and early 1950s his survey results confirming that men are aroused more easily and often by sexual imagery than women. It made sense, evolutionary psychologists theorized, that women’s erotic pleasure might be tempered by the potential burdens of pregnancy, birth and child rearing — that they would require a deeper emotional connection with a partner to feel turned on than men, whose primal urge is simply procreation. Modern statistics showing that men are still the dominant consumers of online porn seem to support this thinking, as does the fact that men are more prone to hypersexuality, whereas a lack of desire and anorgasmia are more prevalent in women. So it was somewhat surprising when a paper in the prestigious journal P.N.A.S. reported in July that what happens in the brains of female study subjects when they look at sexual imagery is pretty much the same as what happens in the brains of their male counterparts. The researchers, led by Hamid Noori at the Max Planck Institute for Biological Cybernetics in Germany, weren’t initially interested in exploring sexual behavior. They were trying to find ways to standardize experiments that use functional magnetic resonance imaging (fM.R.I.) to observe how the brain responds to visual stimuli. In order to do that, they needed to compare past studies that used similar methods but returned diverse results. They happened to choose studies in which male and female volunteers looked at sexual imagery, both because doing so tends to generate strong signals in the brain, which would make findings easier to analyze, and because this sort of research has long produced “inconsistent and even contradictory” results, as they note in their paper. Identifying the reasons for such discrepancies might help researchers design better experiments. © 2019 The New York Times Company

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 2: Functional Neuroanatomy: The Cells and Structure of the Nervous System
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 1: Cells and Structures: The Anatomy of the Nervous System
Link ID: 26622 - Posted: 09.18.2019

By Emily Oster At some point or another, most books about the brain come back to the story of Phineas Gage. Gage was a railroad worker in the 19th century. In an unfortunate 1848 accident, a large steel spike was driven through his eye and out the other side of his head, taking some of his brain with him (this is the point in the story where my 8-year-old told me to please stop telling it). Amazingly, Gage survived the accident with much of his faculties intact. What did change was his personality, which, by many reports, became more aggressive and belligerent. Gage’s doctor wrote up his case, arguing that it suggested “civilized conduct” was localized in a particular part of the brain — specifically, the part he had lost. Science was off in search of where in the brain various skills were kept, with the idea that the brain was a kind of map, with little areas for, say, walking or talking or hearing or smelling. This proceeded, albeit slowly; for a while, there wasn’t much of a way to study this other than by looking at people with traumatic brain injuries. So it’s understandable that the development of technologies to study intact brains caused a lot of excitement. Generating the most discussion in recent years has been functional magnetic resonance imaging (or fMRI), which allows researchers to measure oxygen flow to the brain and identify which parts activate in response to varying stimuli. These technologies have not always lived up to the hype. The mechanics and statistics of processing fMRI imaging data have turned out to be far more complex than initially imagined. As a result there were many false claims made about which parts of the brain “controlled” different aspects of behavior or actions. The best, or at least funniest, example of this was a paper that showed how cutting-edge statistical analysis of fMRI made it possible to identify parts of the brain that responded differently to happy or sad faces. Sounds good, until you learn that the subject for this experiment was a dead fish. © 2019 The New York Times Company

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 2: Functional Neuroanatomy: The Cells and Structure of the Nervous System
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 1: Cells and Structures: The Anatomy of the Nervous System
Link ID: 26594 - Posted: 09.10.2019

/ By Hope Reese In her new book “Gender and Our Brains,” cognitive neuroimaging professor Gina Rippon explains that brains aren’t gendered, but research can be. The differences among women as a group, or men as a group, are greater than the differences between men and women, Rippon says. Rippon sifts through centuries of research into supposed differences in areas such as behavior, skills, and personality, and shows that external factors like gender stereotypes and real-world experiences are the likely cause of any detectable differences in mental processing. And she demonstrates that the differences among women as a group, or among men as a group, are much greater than the differences between men and women. She cites a 2015 study looking at 1,400 brain scans as an example. Comparing 160 brain structures in the scans — identifying areas that were, on average, larger in men or in women — researchers could not find any scans that had all “male” traits, or all “female” traits — physical attributes such as weight or tissue thickness. “The images were, literally, of a mosaic,” she says. “We’re trying to force a difference into data that doesn’t exist.” Rippon teaches cognitive neuroimaging — the study of behavior through brain images — at Aston University in England. For this installment of the Undark Five, I spoke with her about how neuroimages are misinterpreted and whether PMS is real, among other topics. Here is our conversation, edited for length and clarity. Undark: Scientists have been trying to find differences in the brains of men and women for years. What are some examples of how the cherry-picking approach is problematic? Gina Rippon: It’s what I call the “hunt the differences” agenda, which started about 200 years ago when scientists were starting to understand the importance of the brain in explaining human behavior and human ability. Copyright 2019 Undark

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 2: Functional Neuroanatomy: The Cells and Structure of the Nervous System
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 1: Cells and Structures: The Anatomy of the Nervous System
Link ID: 26584 - Posted: 09.07.2019

By Pam Belluck How do genes influence our sexuality? The question has long been fraught with controversy. An ambitious new study — the largest ever to analyze the genetics of same-sex sexual behavior — found that genetics does play a role, responsible for perhaps a third of the influence on whether someone has same-sex sex. The influence comes not from one gene but many, each with a tiny effect — and the rest of the explanation includes social or environmental factors — making it impossible to use genes to predict someone’s sexuality. “I hope that the science can be used to educate people a little bit more about how natural and normal same-sex behavior is,” said Benjamin Neale, a geneticist at the Broad Institute of M.I.T. and Harvard and one of the lead researchers on the international team. “It’s written into our genes and it’s part of our environment. This is part of our species and it’s part of who we are.” The study of nearly half a million people, funded by the National Institutes of Health and other agencies, found differences in the genetic details of same-sex behavior in men and women. The research also suggests the genetics of same-sex sexual behavior shares some correlation with genes involved in some mental health issues and personality traits — although the authors said that overlap could simply reflect the stress of enduring societal prejudice. Even before its publication Thursday in the journal Science, the study has generated debate and concern, including within the renowned Broad Institute itself. Several scientists who are part of the L.G.B.T.Q. community there said they were worried the findings could give ammunition to people who seek to use science to bolster biases and discrimination against gay people. One concern is that evidence that genes influence same-sex behavior could cause anti-gay activists to call for gene editing or embryo selection, even if that would be technically impossible. Another fear is that evidence that genes play only a partial role could embolden people who insist being gay is a choice and who advocate tactics like conversion therapy. © 2019 The New York Times Company

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 13: Memory and Learning
Link ID: 26555 - Posted: 08.30.2019

By Lindsey Bever There is no one gene that determines a person’s sexual orientation, but genetics — along with environment — play a part in shaping sexuality, a massive new study shows. Researchers analyzed DNA from hundreds of thousands of people and found that there are a handful of genes clearly connected with same-sex sexual behavior. The researchers say that, although variations in these genes cannot predict whether a person is gay, these variants may partly influence sexual behavior. Andrea Ganna, lead author and European Molecular Biology Laboratory group leader at the Institute of Molecular Medicine in Finland, said the research reinforces the understanding that same-sex sexual behavior is simply “a natural part of our diversity as a species.” The new study, published Thursday in the journal Science, is not the first to explore the link between genetics and same-sex behavior, but it is the largest of its kind, and experts say it provides one of the clearest pictures of genes and sexuality. Ganna, who is also an instructor at Massachusetts General and Harvard, and an international team of scientists examined data from more than 470,000 people in the United States and the United Kingdom to see whether certain genetic markers in their DNA were linked to their sexual behavior. Specifically, the researchers used data from the UK Biobank study and from the private genomics company 23andMe, which included their DNA data and responses to questions about sexual behaviors, sexual attraction and sexual identity. More than 26,000 participants reported at least one sexual encounter with someone of the same sex. Earlier studies, the researchers said, weren’t large enough to reveal the subtle effects of individual genes. © 1996-2019 The Washington Post

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 26554 - Posted: 08.30.2019

By Annie Roth Kalutas live fast and die young — or, at least, the males do. Male kalutas, small mouselike marsupials found in the arid regions of Northwestern Australia, are semelparous, meaning that shortly after they mate, they drop dead. This extreme reproductive strategy is rare in the animal kingdom. Only a few dozen species are known to reproduce in this fashion, and most of them are invertebrates. Kalutas are dasyurids, the only group of mammals known to contain semelparous species. Only around a fifth of the species in this group of carnivorous marsupials — which includes Tasmanian devils, quolls and pouched mice — are semelparous and, until recently, scientists were not sure if kalutas were among them. Now there is no doubt that, for male kalutas, sex is suicide. In a study, published in April in the Journal of Zoology, researchers from the University of Western Australia and the University of Queensland confirmed that kalutas exhibit what is known as obligate male semelparity. “We found that males only mate during one highly synchronized breeding season and then they all die,” said Genevieve Hayes, a vertebrate ecologist and the lead author of the study. Dr. Hayes and her colleagues monitored the breeding habits of a population of kalutas in Millstream Chichester National Park in Western Australia during the 2013 and 2014 breeding seasons. In both seasons, the researchers observed a complete die-off of males. Although male kalutas have exhibited semelparity in captivity, this was the first time it had been seen in the wild. Kalutas evolved independently of other semelparous dasyurids, so the confirmation that male kalutas die after mating suggests that this unorthodox reproductive strategy has evolved not once, but twice in dasyurids.

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 26552 - Posted: 08.29.2019