Chapter 8. Hormones and Sex

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By Jenna Gallegos Pathogens are real jerks. As if infecting and killing plants and animals isn’t bad enough, they can also turn their hosts into zombies that spread the pathogens to their next victim. Now scientists report that bacteria make some victims summon other victims as their dying act. The bacteria hijack the chemical signaling pathway of insects, making them release a burst of hormones that serve as a beacon to attract friends and potential mates right before the bacteria kill off the host. Like malware marauding as an enticing link, the bacteria attract and then infect. Fruit flies are generally pretty good at avoiding hazards. They can detect when food is infected with a dangerous mold or when a parasitic wasp is nearby, said Markus Knaden, a researcher at the Max Planck Institute for Chemical Ecology in Jena, Germany, who was involved in the study. In both cases, the flies won’t lay their eggs near the infectious agent. That’s why Knaden and colleagues at Cornell University were so surprised when they found that flies were actually attracted to other insects with a certain bacterial infection. “If you’re sitting in a theater and someone next to you is coughing, you move to another chair,” said Bill Hansson, one of the Max Planck authors of the study, published Wednesday in the journal Nature Communications. They expected flies to behave the same way, but instead, healthy flies found their sick friends to be extremely attractive. © 1996-2017 The Washington Post

Keyword: Sexual Behavior; Chemical Senses (Smell & Taste)
Link ID: 23964 - Posted: 08.16.2017

Alice H. Eagly It’s no secret that Silicon Valley employs many more men than women in tech jobs. What’s much harder to agree on is why. The recent anti-diversity memo by a now former Google engineer has pushed this topic into the spotlight. The writer argued there are ways to explain the gender gap in tech that don’t rely on bias and discrimination – specifically, biological sex differences. Setting aside how this assertion would affect questions about how to move toward greater equity in tech fields, how well does his wrap-up represent what researchers know about the science of sex and gender? As a social scientist who’s been conducting psychological research about sex and gender for almost 50 years, I agree that biological differences between the sexes likely are part of the reason we see fewer women than men in the ranks of Silicon Valley’s tech workers. But the road between biology and employment is long and bumpy, and any causal connection does not rule out the relevance of nonbiological causes. Here’s what the research actually says. There is no direct causal evidence that biology causes the lack of women in tech jobs. But many, if not most, psychologists do give credence to the general idea that prenatal and early postnatal exposure to hormones such as testosterone and other androgens affect human psychology. In humans, testosterone is ordinarily elevated in males from about weeks eight to 24 of gestation and also during early postnatal development. © 2010–2017, The Conversation US, Inc.

Keyword: Sexual Behavior; Development of the Brain
Link ID: 23963 - Posted: 08.16.2017

Allison Aubrey What we eat can influence more than our waistlines. It turns out, our diets also help determine what we smell like. A recent study found that women preferred the body odor of men who ate a lot of fruits and vegetables, whereas men who ate a lot of refined carbohydrates (think bread, pasta) gave off a smell that was less appealing. Skeptical? At first, I was, too. I thought this line of inquiry must have been dreamed up by the produce industry. (Makes a good marketing campaign, right?) But it's legit. "We've known for a while that odor is an important component of attractiveness, especially for women," says Ian Stephen of Macquarie University in Australia. He studies evolution, genetics and psychology and is an author of the study. From an evolutionary perspective, scientists say our sweat can help signal our health status and could possibly play a role in helping to attract a mate. How did scientists evaluate the link between diet and the attractiveness of body odor? They began by recruiting a bunch of healthy, young men. They assessed the men's skin using an instrument called a spectrophotometer. When people eat a lot of colorful veggies, their skin takes on the hue of carotenoids, the plant pigments that are responsible for bright red, yellow and orange foods. "The carotenoids get deposited in our skin," explains Stephen. © 2017 npr

Keyword: Chemical Senses (Smell & Taste); Sexual Behavior
Link ID: 23961 - Posted: 08.15.2017

Eric Deggans Like a lot of kids in high school, Sam worries that he doesn't fit in. "I'm a weirdo. That's what everyone says," declares the 18-year-old character at the center of Netflix's new dramatic comedy series Atypical. One reason Sam struggles to fit in: He has autism. As his character explains at the start of the first episode, sometimes he doesn't understand what people mean when they say things. And that makes him feel alone, even when he's not. Sam's family in Atypical is thrown in all sorts of new directions by his quest to date and find a girlfriend. Creator Robia Rashid says she wanted to tell a different kind of coming-of-age story, inspired by recent increases in autism diagnoses. "There are all these young people now who are on the spectrum, who know ... they're on the spectrum," she says. "And [they] are interested in things that every young person is interested in ... independence and finding connections and finding love." On-screen depictions of autism have come a long way since Dustin Hoffman's portrayal of Raymond Babbitt in the 1988 Oscar-winning film Rain Man. Hoffman's Babbitt focused obsessively on watching The People's Court and getting served maple syrup before his pancakes. He could also memorize half the names in a phone book in one reading and count the number of toothpicks on the floor, moments after they spilled out of the box. For Atypical, Rashid says she researched accounts of adults with autism, has several parents of autistic children working in her crew and hired an actor with autism to play a minor role. © 2017 npr

Keyword: Autism
Link ID: 23953 - Posted: 08.12.2017

Conor Friedersdorf This week, headlines across a diverse array of media outlets proclaimed that at least one Google employee was so antagonistic to women that he circulated a 10-page “anti-diversity screed.” That is how Gizmodo characterized the now infamous internal memo when publishing it Saturday. Similar language was used in headlines at Fox News, CNN, ABC News, the BBC, NBC News, Time, Slate, Engadget, The Huffington Post, PBS, Fast Company, and beyond (including a fleeting appearance in a headline here at The Atlantic). But love or hate the memo, which makes a number of substantive claims, some of which I regard as wrongheaded (and which would’ve benefitted greatly from an editor with more emotional intelligence than the author to help him avoid alienating his audience, even if he was determined to raise all of the same arguments), the many characterizations of the memo as “anti-diversity” are inaccurate. Using that shorthand is highly misleading. As many who read past the headlines would later observe, its author, who was later fired, began, “I value diversity and inclusion, am not denying that sexism exists, and don’t endorse using stereotypes. When addressing the gap in representation in the population, we need to look at population level differences in distributions. If we can’t have an honest discussion about this, then we can never truly solve the problem.” The balance of his memo argues that he is not against pursuing greater gender diversity at Google; he says it is against the current means Google is using to pursue that end and the way the company conceives of tradeoffs between the good of diversity and other goods. (c) 2017 by The Atlantic Monthly Group.

Keyword: Sexual Behavior
Link ID: 23941 - Posted: 08.10.2017

By NICHOLAS BAKALAR The incidence of stroke has declined in recent years, but only in men. Researchers studied stroke incidence in four periods from 1993 to 2010 in five counties in Ohio and Kentucky. There were 7,710 strokes all together, 57.2 percent of them in women. After adjusting for age and race, they found that stroke incidence in men had decreased to 192 per hundred thousand men in 2010, down from 263 in 1993–94. But for women the incidence was 198 per hundred thousand in 2010, down from 217 in 1993–94, a statistically insignificant change. The study is in Neurology. Most of the difference was in ischemic stroke, the most common cause, resulting from a blocked blood vessel supplying blood to the brain. No one knows why there has been no improvement in women, but the lead author, Dr. Tracy E. Madsen, an assistant professor of emergency medicine at Brown, said that some risk factors have a stronger effect in women than in men. Risk factors for stroke include high blood pressure, heart disease, diabetes and smoking. “Maybe we’re not controlling risk factors to the same extent in women. Or maybe there’s a biological difference in the way these risk factors cause strokes in men versus women.” In any case, Dr. Madsen said, “It’s important for women to know they are at risk. Stroke has been considered a male disease, but we know that it is very prevalent in women and has a high risk of disability and death.” © 2017 The New York Times Company

Keyword: Stroke; Sexual Behavior
Link ID: 23939 - Posted: 08.10.2017

By Jamie Strashin, The look on Melissa Bishop's face said it all. The Canadian 800-metre star had just run the race of her life, at the best possible moment, on the world's biggest stage. "I have never run faster in my life. It's the smartest race I have ever put down on a track," Bishop said of her performance in the final at the Rio Olympics last summer. But it still wasn't enough. Despite setting a new Canadian record (which she has since broken by running a 1:57.01), Bishop finished fourth in the Rio final, missing a bronze medal by 13 hundredths of a second. Perhaps more distressingly, she crossed the line close to two seconds slower than gold medallist Caster Semenya. "I remember seeing my agent and just falling into his arms, thinking, I can't believe this just happened. What just happened?" Bishop recalled. "And then I saw my dad, and my dad is a very emotional man and he was livid. Not because of how I raced, but because of the scenario we were in. And he just kept telling me, 'You have nothing to be ashamed of.'" The "scenario" of finishing well behind Semenya is a familiar one for competitors since the South African burst onto the scene at the 2009 world track and field championships. As an 18-year-old in Berlin, Semenya blasted away her competition, winning by almost two and a half seconds and clocking the fastest time of the year. Caster Semenya dominates 800m at 2009 world championships ©2017 CBC/Radio-Canada.

Keyword: Sexual Behavior
Link ID: 23933 - Posted: 08.09.2017

By GINA KOLATA For middle-aged women struggling with their weight, a recent spate of scientific findings sounds too good to be true. And they may be, researchers caution. Studies in mice indicate that a single hormone whose levels rise at menopause could be responsible for a characteristic redistribution of weight in middle age to the abdomen, turning many women from “pears” to “apples.” At the same time, the hormone may spur the loss of bone. In mouse studies, blocking the hormone solves those problems, increasing the calories burned, reducing abdominal fat, slowing bone loss and even encouraging physical activity. The notion that such a simple intervention could solve two big problems of menopause has received the attention of researchers and has prompted commentaries in prestigious journals like The New England Journal of Medicine and Cell Metabolism. “It’s a super interesting idea,” said Dr. Daniel Bessesen, an obesity expert and professor of medicine at the University of Colorado School of Medicine. With obesity rising, “we definitely need some new ideas.” The work began when Dr. Mone Zaidi, a professor of medicine at the Icahn School of Medicine at Mount Sinai in New York City, became curious about whether a reproductive hormone — F.S.H., or follicle-stimulating hormone — affects bone density. It had long been assumed that the hormone’s role was limited to reproduction. F.S.H. stimulates the production of eggs in women and sperm in men. Researchers knew that blood levels of F.S.H. soar as women’s ovaries start to fail before menopause. At the same time, women rapidly lose bone — even when blood levels of estrogen, which can preserve bone, remain steady. © 2017 The New York Times Company

Keyword: Obesity; Hormones & Behavior
Link ID: 23929 - Posted: 08.08.2017

/ By Florence Williams The 17th century ushered in an astonishing age of scientific discovery, from Galileo’s positioning of the sun in the heavens to Newton’s Laws of Motion to Francis Bacon’s empiricism. Armed with new swagger and understanding, the scientific rationalists of the day figured the pivot from astronomy and physics to biology would be a piece of cake. The workings of the universe had been proved to adhere to laws and formulas. All would be properly unveiled in due time. “The bold men of science,” Edward Dolnick writes, “raced off to take on the mystery of life and promptly face-planted.” How mistaken they were. As Edward Dolnick writes in his amusing and informative “The Seeds of Life,” “The bold men of science raced off to take on the mystery of life and promptly face-planted.” In fact, they were fairly undone, partly by their own pigheaded biases and partly by the truly mystifying matters of genes and heredity, for which they were woefully ill prepared. It was not until 1875 that a German scientist finally put the sperm and the egg together conceptually. The journey to that insight was sometimes comical, sometimes misguided, and usually revealing of cultural mores, gender politics, and societal blind spots. Consider, for example, the common scientific belief that a woman’s contribution to baby-making must surely be minimal. Copyright 2017 Undark

Keyword: Sexual Behavior; Development of the Brain
Link ID: 23921 - Posted: 08.07.2017

Daniel Trotta NEW YORK (Reuters) - While President Donald Trump has thrust transgender people back into the conflict between conservative and liberal values in the United States, geneticists are quietly working on a major research effort to unlock the secrets of gender identity. A consortium of five research institutions in Europe and the United States, including Vanderbilt University Medical Center, George Washington University and Boston Children's Hospital, is looking to the genome, a person's complete set of DNA, for clues about whether transgender people are born that way. Two decades of brain research have provided hints of a biological origin to being transgender, but no irrefutable conclusions. Now scientists in the consortium have embarked on what they call the largest-ever study of its kind, searching for a genetic component to explain why people assigned one gender at birth so persistently identify as the other, often from very early childhood. (reut.rs/2w3Ozg9) Researchers have extracted DNA from the blood samples of 10,000 people, 3,000 of them transgender and the rest non-transgender, or cisgender. The project is awaiting grant funding to begin the next phase: testing about 3 million markers, or variations, across the genome for all of the samples.

Keyword: Sexual Behavior; Genes & Behavior
Link ID: 23919 - Posted: 08.05.2017

/ By Deborah Blum I’m hesitating over this one question I want to ask the scientist on the phone, a federal researcher studying the health effects of soy formula on infants. I worry that it’s going to sound slightly Dr. Frankenstein-esque. Finally, I spill it out anyway: “Are we talking about a kind of accidental experiment in altering child development?” The line goes briefly silent. “I’m a little worried about the word ‘experiment,’” replies Jack Taylor, a senior investigator at the National Institute of Environmental Health Sciences, a division of the National Institutes of Health. Taylor and his colleagues in North Carolina have been comparing developmental changes in babies fed soy formula, cow-milk formula, and breastmilk. His group’s most recent paper, “Soy Formula and Epigenetic Modifications,” reported that soy-fed infant girls show some distinct genetic changes in vaginal cells, possibly “associated with decreased expression of an estrogen-responsive gene.” But his first reaction is that my phrasing would, incorrectly, “make it sound like we were giving children a bad drug on purpose.” The research group, he emphasizes, is merely comparing the health of infants after their parents independently choose a preferred feeding method. No one is forcing soy formula on innocent infants. “No, no, that’s not what I meant,” I explain with some hurry. “I wasn’t suggesting that you were experimenting on children.” Rather, I was wondering whether we as a culture, with our fondness for all things soy, have created a kind of inadvertent national study. Soy accounts for about 12 percent of the U.S. formula market and I’ve become increasingly curious about what this means. Because the science does seem to suggest that we are rather casually testing the effect of plant hormones on human development, most effectively by feeding infants a constant diet of a food rich in such compounds. Copyright 2017 Undark

Keyword: Hormones & Behavior; Sexual Behavior
Link ID: 23912 - Posted: 08.03.2017

Laura Sanders The company mice keep can change their behavior. In some ways, genetically normal littermates behave like mice that carry an autism-related mutation, despite not having the mutation themselves, scientists report. The results, published July 31 in eNeuro, suggest that the social environment influences behavior in complex and important ways, says neuroscientist Alice Luo Clayton of the Simons Foundation Autism Research Initiative in New York City. The finding comes from looking past the mutated mice to their nonmutated littermates, which are usually not a subject of scrutiny. “People almost never look at it from that direction,” says Clayton, who wasn’t involved in the study. Researchers initially planned to investigate the social behavior of mice that carried a mutation found in some people with autism. Studying nonmutated mice wasn’t part of the plan. “We stumbled into this,” says study coauthor Stéphane Baudouin, a neurobiologist at Cardiff University in Wales. Baudouin and colleagues studied groups of mice that had been genetically modified to lack neuroligin-3, a gene that is mutated in some people with autism. Without the gene, the mice didn’t have Neuroligin-3 in their brains, a protein that helps nerve cells communicate. Along with other behavioral quirks, these mice didn’t show interest in sniffing other mice, as expected. But Baudouin noticed that the behavior of the nonmutated control mice who lived with the neuroligin-3 mutants also seemed off. He suspected that the behavior of the mutated mice might be to blame. |© Society for Science & the Public 2000 - 2017.

Keyword: Autism; Genes & Behavior
Link ID: 23905 - Posted: 08.01.2017

By Daisy Yuhas, When the shy, dark-haired boy met with clinicians for a full psychiatric evaluation two years ago, almost everything about him pointed to autism. W. had not spoken his first words until age 2. He was at least 4 before he could form sentences. As he got older, he was unable to make friends. He struggled to accept changes to his routine and maintain eye contact. And despite having an average intelligence quotient, he was unusually attached to objects; at age 11, he still lugged a bag of stuffed animals with him everywhere he went. But something else was clearly at work, too. “He had these things that he would call day dreams,” recalls Jennifer Foss-Feig, assistant professor of psychiatry at the Icahn School of Medicine at Mount Sinai in New York. When she evaluated W., she noticed that he would often gaze into an empty corner of the room—particularly when he seemed to suspect that she wasn’t paying attention to him. (For privacy reasons, Foss-Feig declined to reveal anything but the child’s first initial.) Occasionally, he would speak to that space, as though someone else were there. His parents, she recalls, were worried. They explained to Foss-Feig that their son had what he called an “imaginary family.” But W.’s invisible playmates weren’t of the usual harmless variety that many children have; they seemed to be a dangerous distraction both at home and at school. On one occasion, he wandered through a busy parking lot, seemingly oblivious to the oncoming traffic. © 2017 Scientific America

Keyword: Autism; Schizophrenia
Link ID: 23874 - Posted: 07.25.2017

By JANE E. BRODY Problems with estrogen and testosterone, the body’s main sex hormones, tend to attract widespread public interest. But we might all be better off paying more attention to a far more common endocrine disorder: abnormal levels of thyroid hormone. Thyroid disorders can affect a wide range of bodily functions and cause an array of confusing and often misdiagnosed symptoms. Because the thyroid, a small gland in the neck behind the larynx, regulates energy production and metabolism throughout the body, including the heart, brain, skin, bowels and body temperature, too much or too little of its hormones can have a major impact on health and well-being. Yet in a significant number of people with thyroid deficiencies, routine blood tests fail to detect insufficient thyroid hormone, leaving patients without an accurate explanation for their symptoms. These can include excessive fatigue, depression, hair loss, unexplained weight gain, constipation, sleep problems, mental fogginess and anxiety. Women of childbearing age may have difficulty getting pregnant or staying pregnant. Although thyroid disorders are more common in adults, children, whose cognitive and physical development depend on normal thyroid function, are not necessarily spared. In a review article published last year in JAMA Pediatrics, doctors from the Children’s Hospital of Philadelphia pressed primary care doctors to recognize childhood thyroid disease and begin treatment as early as the second week of life to ensure normal development. Hypothyroidism — low hormone levels — in particular is often misdiagnosed, its symptoms resembling those of other diseases or mistaken for “normal” effects of aging. Indeed, the risk of hypothyroidism rises with age. Twenty percent of people over 75, most of them women, lack sufficient levels of thyroid hormone that, among other problems, can cause symptoms of confusion commonly mistaken for dementia. © 2017 The New York Times Company

Keyword: Hormones & Behavior
Link ID: 23866 - Posted: 07.24.2017

Jon Hamilton Professional fighter Gina Mazany practices during a training session at Xtreme Couture Mixed Martial Arts in Las Vegas. She well remembers her first concussion — which came in her first fight. "I was throwing up that night, Mazany says. Bridget Bennett for NPR Gina Mazany grew up in Anchorage, Alaska. And that's where she had her first fight. "It was right after I turned 18," she recalls. A local bar had a boxing ring, and Mazany decided to give it a shot. Her opponent was an older woman with a "mom haircut." "She beat the crap out of me," Mazany says. "Like she didn't knock me out, she didn't finish me. But she just knocked me around for three rounds. And I remember, later that night I was very, very nauseous. I was throwing up that night." It was her first concussion. Concussions are just part of her sport, Mazany figures, but says she tries to protect herself, and to not give anyone else a head injury--at least in training. Bridget Bennett for NPR Thanks to research on boxers and football players, both athletes and the public are becoming more aware of the dangers of sports-related head injuries. Yet there is little data on participants like Mazany. That's because, unlike the vast majority of athletes studied, she is a woman. "We classically have always known the male response to brain injury," says Mark Burns, at Georgetown University. But there have been remarkably few studies of females. The bias runs throughout the scientific literature, even in studies of mice. © 2017 npr

Keyword: Brain Injury/Concussion
Link ID: 23865 - Posted: 07.24.2017

by Laurel Hamers The tempo of a male elephant seal’s call broadcasts his identity to rival males, a new study finds. Every male elephant seal has a distinct vocalization that sounds something like a sputtering lawnmower — pulses of sound in a pattern and at a pace that stays the same over time. At a California state park where elephant seals breed each year, researchers played different variations of an alpha male’s threat call to subordinate males who knew him. The seals weren’t as responsive when the tempo of that call was modified substantially, suggesting they didn’t recognize it as a threat. Modifying the call’s timbre — the acoustic quality of the sound — had the same effect, researchers report August 7 in Current Biology. Unlike dolphins and songbirds, elephant seals don’t seem to vary pitch to communicate. Those vocal name tags serve a purpose. During breeding season, male elephant seals spend three months on land without food or water, competing with rivals for social status and mating rights. Fights between two blubbery car-sized animals can be brutal. “We’ve seen males lose their noses,” says Caroline Casey, a biologist at the University of California, Santa Cruz. For lower-ranking males, identifying an alpha male by his call and then backing off might prevent a beach brawl. |© Society for Science & the Public 2000 - 2017

Keyword: Animal Communication; Sexual Behavior
Link ID: 23859 - Posted: 07.21.2017

Xiaomeng (Mona) Xu, assistant professor of experimental psychology, and Ariana Tart-Zelvin, If you have experienced the evolution from having a crush to falling in love, it may seem like the transition happens naturally. But have you ever wondered how we make such a huge emotional leap? In other words, what changes take place in our brains that allow us to fall deeply in love? Stephanie Cacioppo, a psychologist at the University of Chicago who has studied the neuroscience of romantic love for the past decade, explains that the process involves several complex changes, particularly in the brain’s reward system. More specifically, in a 2012 review of the love research literature Lisa Diamond and Janna Dickenson, psychologists at the University of Utah, found romantic love is most consistently associated with activity in two brain regions—the ventral tegmental area (VTA) and the caudate nucleus. These areas play an essential role in our reward pathway and regulate the “feel good” neurotransmitter dopamine. In other words, during the early stages of love you crave the person because he or she makes you feel so good. And over time these feelings persist. Our neuroimaging research and that of others suggests that once you are in love—as long as the relationship remains satisfying—simply thinking about your partner not only makes you feel good but can also buffer against pain, stress and other negative feelings. © 2017 Scientific American,

Keyword: Emotions; Sexual Behavior
Link ID: 23852 - Posted: 07.20.2017

Hannah Devlin Science correspondent Brash, brawny and keen to impose their will on anyone who enters their sphere of existence: the alpha male in action is unmistakable. Now scientists claim to have pinpointed the biological root of domineering behaviour. New research has located a brain circuit that, when activated in mice, transformed timid individuals into bold alpha mice that almost always prevailed in aggressive social encounters. In some cases, the social ranking of the subordinate mice soared after the scientists’ intervention, hinting that it might be possible to acquire “alphaness” simply by adopting the appropriate mental attitude. Or as Donald Trump might put it: “My whole life is about winning. I almost never lose.” Prof Hailan Hu, a neuroscientist at Zhejiang University in Hangzhou, China, who led the work said: “We stimulate this brain region and we can make lower ranked mice move up the social ladder.” The brain region, called the dorsal medial prefrontal cortex (dmPFC), was already known to light up during social interactions involving decisions about whether to be assertive or submissive with others. But brain imaging alone could not determine whether the circuit was ultimately controlling how people behave. The latest findings answer the question, showing that when the circuit was artificially switched on, low-ranking mice were immediately emboldened. “It’s not aggressiveness per se,” Hu said. “It increases their perseverance, motivational drive, grit.” © 2017 Guardian News and Media Limited

Keyword: Aggression; Sexual Behavior
Link ID: 23836 - Posted: 07.14.2017

By PAM BELLUCK How we look at other people’s faces is strongly influenced by our genes, scientists have found in new research that may be especially important for understanding autism because it suggests that people are born with neurological differences that affect how they develop socially. The study, published on Wednesday in the journal Nature, adds new pieces to the nature-versus-nurture puzzle, suggesting that genetics underlie how children seek out formative social experiences like making eye contact or observing facial expressions. Experts said the study may also provide a road map for scientists searching for genes linked to autism. “These are very convincing findings, novel findings,” said Charles A. Nelson III, a professor of pediatrics and neuroscience at Harvard Medical School and Boston Children’s Hospital, who was not involved in the research. “They seem to suggest that there’s a genetic underpinning that leads to different patterns of brain development, that leads some kids to develop autism.” Dr. Nelson, an expert in child development and autism who was an independent reviewer of the study for Nature, said that while autism is known to have a genetic basis, how specific genes influence autism’s development remains undetermined. The study provides detailed data on how children look at faces, including which features they focus on and when they move their eyes from one place to another. The information, Dr. Nelson said, could help scientists “work out the circuitry that controls these eye movements, and then we ought to be able to work out which genes are being expressed in that circuit.” “That would be a big advance in autism,” he said. In the study, scientists tracked the eye movements of 338 toddlers while they watched videos of motherly women as well as of children playing in a day care center. The toddlers, 18 months to 24 months old, included 250 children who were developing normally (41 pairs of identical twins, 42 pairs of nonidentical twins and 84 children unrelated to each other). There were also 88 children with autism. © 2017 The New York Times Company

Keyword: Autism; Vision
Link ID: 23832 - Posted: 07.13.2017

By Giorgia Guglielmi Semen has something in common with the brains of Alzheimer’s sufferers: Both contain bundles of protein filaments called amyloid fibrils. But although amyloid accumulation appears to damage brain cells, these fibrils may be critical for reproduction. A new study suggests that semen fibrils immobilize subpar sperm, ensuring that only the fittest ones make it to the egg. “I’m sure that from the very first time scientists described semen fibrils, they must have been speculating what their natural function was,” says Daniel Otzen, an expert in protein aggregates at Aarhus University in Denmark, who did not participate in the research. “This seems to be the smoking gun.” Researchers discovered semen fibrils in 2007. At first, they seemed like mostly bad news. Scientists showed that the fibrils, found in the seminal fluid together with sperm cells and other components, can bind to HIV, helping it get inside cells. But the fibrils are found in most primates, notes Nadia Roan, a mucosal biologist at the University of California, San Francisco. “If fibrils didn’t serve some beneficial purpose, they would have been eliminated over evolutionary time.” Because the way HIV fuses to cells is reminiscent of the way a sperm fuses to the egg, she wondered whether the fibrils facilitated fertilization. © 2017 American Association for the Advancement of Science.

Keyword: Alzheimers; Sexual Behavior
Link ID: 23828 - Posted: 07.12.2017