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Londa Schiebinger. In Madrid a couple of years ago, I was interviewed for Spanish newspapers. When I later ran the text through Google Translate, I got a shock: I was referred to repeatedly as “he”. Like much science and technology, Google Translate has a male default. When I drive a car, the seatbelt is not designed to accommodate breast tissue. Any medicines I take are more likely to have been tested on male than on female animals. There are moral issues here: women pay taxes and buy products and should not be short-changed. But scientific objectivity is at stake, too. Because medical research is done mainly in males, there is a male bias in, for example, the choice of drug targets. Science is halving the potential field of innovation. This is not about active discrimination; the bias is largely unconscious. Google Translate defaults to the masculine pronoun because 'he' is more commonly found on the Web than 'she'. Yet that is changing: an analysis of American-English texts in Google Books shows that the ratio of masculine to feminine pronouns has fallen to around 2:1, from a peak of 4:1 in the 1960s. In the summer of 2012, I invited Google and several language-processing experts to a Gendered Innovations workshop at Harvard University in Cambridge, Massachusetts. They listened to the problem for about 20 minutes, then said: “We can fix that!” Although it is complicated, the search for solutions is on. Fixing the problem is great, but constantly retrofitting for women is not the best road forwards. A better way is to include gender at all relevant phases of research — when setting priorities, gathering and analysing data, evaluating results, developing patents and, finally, transferring ideas to markets. Science and technology should take into account the biological and social needs of both women and men. Unconscious sex and gender bias can be socially harmful and expensive. © 2014 Nature Publishing Group
Keyword: Sexual Behavior
Link ID: 19329 - Posted: 03.06.2014
New findings reveal how a mutation, a change in the genetic code that causes neurodegeneration, alters the shape of DNA, making cells more vulnerable to stress and more likely to die. The particular mutation, in the C9orf72 gene, is the most common cause for amyotrophic lateral sclerosis (ALS, also known as Lou Gehrig’s disease), and frontotemporal degeneration (FTD), the second most common type of dementia in people under 65. This research by Jiou Wang, Ph.D., and his colleagues at Johns Hopkins University (JHU) was published in Nature and was partially funded by the National Institutes of Health’s National Institute of Neurological Disorders and Stroke (NINDS). In ALS, the muscle-activating neurons in the spinal cord die, eventually causing paralysis. In FTD neurons in particular brain areas die leading to progressive loss of cognitive abilities. The mutation may also be associated with Alzheimer’s and Huntington’s diseases. DNA contains a person’s genetic code, which is made up of a unique string of bases, chemicals represented by letters. Portions of this code are divided into genes that provide instructions for making molecules (proteins) that control how cells function. The normal C9orf72 gene contains a section of repeating letters; in most people, this sequence is repeated two to 25 times. In contrast, the mutation associated with ALS and FTD can result in up to tens of thousands of repeats of this section.
Clara Moskowitz When mathematicians describe equations as beautiful, they are not lying. Brain scans show that their minds respond to beautiful equations in the same way other people respond to great paintings or masterful music. The finding could bring neuroscientists closer to understanding the neural basis of beauty, a concept that is surprisingly hard to define. In the study, researchers led by Semir Zeki of University College London asked 16 mathematicians to rate 60 equations on a scale ranging from "ugly" to "beautiful." Two weeks later, the mathematicians viewed the same equations and rated them again while lying inside a functional magnetic resonance imaging (fMRI) scanner. The scientists found that the more beautiful an equation was to the mathematician, the more activity his or her brain showed in an area called the A1 field of the medial orbitofrontal cortex. The orbitofrontal cortex is associated with emotion, and this particular region of it has shown in previous tests to be correlated with emotional responses to visual and musical beauty. The researchers wondered whether the trend would extend to mathematical beauty, which "has a much deeper intellectual source than visual or musical beauty, which are more 'sensible' and perceptually based," they wrote in a paper reporting their results published on 13 February in Frontiers of Human Neuroscience. Investigating mathematical beauty allowed the researchers to test the role of culture and learning in aesthetic appreciation. The scientists hypothesized that while people with no musical or artistic training can still appreciate Beethoven’s and Michelangelo's works, only those who understand the meaning behind certain mathematical formulas would find them beautiful. © 2014 Nature Publishing Group,
Link ID: 19327 - Posted: 03.06.2014
By Tara Bahrampour, Alzheimer’s disease likely plays a much larger role in the deaths of older Americans than is reported, according to a new study that says the disease may be the third-leading cause of death in the United States. The Centers for Disease Control and Prevention lists Alzheimer’s as the sixth-leading cause of death, far below heart disease and cancer. But the new report, published Wednesday in the medical journal of the American Academy of Neurology, suggests that the current system of relying on death certificates for causes misses the complexity of dying for many older people and underestimates the impact of Alzheimer’s. While the CDC attributed about 84,000 deaths in 2010 to Alzheimer’s, the report estimated that number to be 503,400 among people 75 and older. That puts it in a close third place, behind heart disease and cancer, and well above chronic lung disease, stroke and accidents, which rank third, fourth and fifth. Alzheimer’s is somewhat of a sleeping giant compared with other leading killers that have received more funding over the years. While deaths from these diseases have been going down thanks to better treatment and prevention, the number of people suffering from Alzheimer’s is quickly rising and the disease is always fatal. More than 5 million people in the United States are estimated to have Alzheimer’s. With the aging of the baby-boom generation, this number is expected to nearly triple by 2050 if there are no significant medical breakthroughs, according to the Alzheimer’s Association. © 1996-2014 The Washington Post
Link ID: 19326 - Posted: 03.06.2014
Virginia Hughes When Brian Dias became a father last October, he was, like any new parent, mindful of the enormous responsibility that lay before him. From that moment on, every choice he made could affect his newborn son's physical and psychological development. But, unlike most new parents, Dias was also aware of the influence of his past experiences — not to mention those of his parents, his grandparents and beyond. Where one's ancestors lived, or how much they valued education, can clearly have effects that pass down through the generations. But what about the legacy of their health: whether they smoked, endured famine or fought in a war? As a postdoc in Kerry Ressler's laboratory at Emory University in Atlanta, Georgia, Dias had spent much of the two years before his son's birth studying these kinds of questions in mice. Specifically, he looked at how fear associated with a particular smell affects the animals and leaves an imprint on the brains of their descendants. Dias had been exposing male mice to acetophenone — a chemical with a sweet, almond-like smell — and then giving them a mild foot shock. After being exposed to this treatment five times a day for three days, the mice became reliably fearful, freezing in the presence of acetophenone even when they received no shock. Ten days later, Dias allowed the mice to mate with unexposed females. When their young grew up, many of the animals were more sensitive to acetophenone than to other odours, and more likely to be startled by an unexpected noise during exposure to the smell. Their offspring — the 'grandchildren' of the mice trained to fear the smell — were also jumpier in the presence of acetophenone. What's more, all three generations had larger-than-normal 'M71 glomeruli', structures where acetophenone-sensitive neurons in the nose connect with neurons in the olfactory bulb. In the January issue of Nature Neuroscience1, Dias and Ressler suggested that this hereditary transmission of environmental information was the result of epigenetics — chemical changes to the genome that affect how DNA is packaged and expressed without altering its sequence. © 2014 Nature Publishing Group,
By Debra Weiner An active lifestyle improves brain health, scientists have long believed. The studies bear this out: physical, intellectual and social activity—or “environmental enrichment,” in the parlance—enhances learning and memory and protects against aging and neurological disease. Recent research suggests one benefit of environmental enrichment at the cellular level: it repairs brain myelin, the protective insulation surrounding axons, or nerve fibers, which can be lost because of aging, injury or diseases such as multiple sclerosis. But how does an enriched environment trigger myelin repair in the first place? The answer appears to involve naturally occurring membrane-wrapped packets called exosomes. A number of different cell types release these little sacs of proteins and genetic material into the body's fluids. Loaded with signaling molecules, exosomes spread through the body “like messages in a bottle,” says R. Douglas Fields, a neurobiologist at the National Institutes of Health. They target particular cells and change their behavior. In animal studies, exosomes secreted by immune cells during environmental enrichment caused cells in the brain to start myelin repair. Researchers think exosomes might find use as biomarkers for diagnosing diseases or as vehicles to deliver cancer drugs or other therapeutic agents. The exosomes produced during environmental enrichment carry microRNAs—small pieces of genetic material—which appear to instruct immature cells in the brain to develop into myelin-making cells called oligodendrocytes. When researchers at the University of Chicago withdrew exosomes from the blood of rats and administered them to aging animals, the older rats' myelin levels rose by 62 percent, the team reported in February in Glia. © 2014 Scientific American
By GRETCHEN REYNOLDS Obesity may have harmful effects on the brain, and exercise may counteract many of those negative effects, according to sophisticated new neurological experiments with mice, even when the animals do not lose much weight. While it’s impossible to know if human brains respond in precisely the same way to fat and physical activity, the findings offer one more reason to get out and exercise. It’s been known for some time that obesity can alter cognition in animals. Past experiments with lab rodents, for instance, have shown that obese animals display poor memory and learning skills compared to their normal-weight peers. They don’t recognize familiar objects or recall the location of the exit in mazes that they’ve negotiated multiple times. But scientists hadn’t understood how excess weight affects the brain. Fat cells, they knew, manufacture and release substances into the bloodstream that flow to other parts of the body, including the heart and muscles. There, these substances jump-start biochemical processes that produce severe inflammation and other conditions that can lead to poor health. Many thought the brain, though, should be insulated from those harmful effects. It contains no fat cells and sits behind the protective blood-brain barrier that usually blocks the entry of undesirable molecules. However, recent disquieting studies in animals indicate that obesity weakens that barrier, leaving it leaky and permeable. In obese animals, substances released by fat cells can ooze past the barrier and into the brain. The consequences of that seepage became the subject of new neurological experiments conducted by researchers at Georgia Regents University in Augusta and published last month in The Journal of Neuroscience. © 2014 The New York Times Company
Link ID: 19323 - Posted: 03.05.2014
By BENEDICT CAREY He heard about the drug trial from a friend in Switzerland and decided it was worth volunteering, even if it meant long, painful train journeys from his native Austria and the real possibility of a mental meltdown. He didn’t have much time, after all, and traditional medicine had done nothing to relieve his degenerative spine condition. “I’d never taken the drug before, so I was feeling — well, I think the proper word for it, in English, is dread,” said Peter, 50, an Austrian social worker, in a telephone interview; he asked that his last name be omitted to protect his identity. “There was this fear that it could all go wrong, that it could turn into a bad trip.” On Tuesday, The Journal of Nervous and Mental Disease is posting online results from the first controlled trial of LSD in more than 40 years. The study, conducted in the office of a Swiss psychiatrist near Bern, tested the effects of the drug as a complement to talk therapy for 12 people nearing the end of life, including Peter. Most of the subjects had terminal cancer, and several died within a year after the trial — but not before having a mental adventure that appeared to have eased the existential gloom of their last days. “Their anxiety went down and stayed down,” said Dr. Peter Gasser, who conducted the therapy and followed up with his patients a year after the trial concluded. The new publication marks the latest in a series of baby steps by a loose coalition of researchers and fund-raisers who are working to bring hallucinogens back into the fold of mainstream psychiatry. Before research was banned in 1966 in the United States, doctors tested LSD’s effect for a variety of conditions, including end-of-life anxiety. But in the past few years, psychiatrists in the United States and abroad — working with state regulators as well as ethics boards — have tested Ecstasy-assisted therapy for post-traumatic stress; and other trials with hallucinogens are in the works. © 2014 The New York Times Company
|By Roni Jacobson Modern antipsychotic drugs are increasingly prescribed to children and adolescents diagnosed with a broad variety of ailments. The drugs help to alleviate symptoms in some disorders, such as schizophrenia and bipolar disorder, but in others their effectiveness is questionable. Yet off-label prescribing is on the rise, especially in children receiving public assistance and Medicaid. Psychotic disorders typically arise in adulthood and affect only a small proportion of children and adolescents. Off-label prescriptions, however, most often target aggressive and disruptive behaviors associated with attention-deficit hyperactivity disorder (ADHD). “What's really concerning now is that a lot of this prescription is occurring in the face of emerging evidence that there are significant adverse effects that may be worse in youth than in adults,” says David Rubin, a general pediatrician and co-director of PolicyLab at Children's Hospital of Philadelphia. Here we review the evidence for the effectiveness of antipsychotic medications commonly prescribed for five childhood conditions. But do the benefits outweigh the risks? Schizophrenia Evidence from several randomized controlled trials conducted in the past 10 years strongly suggests that antipsychotics are an effective treatment for youths with schizophrenia. Indeed, the FDA has approved five medications—risperidone, aripiprazole, olanzapine, quetiapine and paliperidone—for use in adolescents aged 13 to 17. Bipolar Disorder Recent research indicates that antipsychotics may hasten the resolution of manic and mixed episodes in children with bipolar disorder and increase the likelihood that the illness will go into remission. The FDA has approved the same set of drugs for 10- to 17-year-olds with bipolar disorder as it has for youths with schizophrenia, with the exception of paliperidone. © 2014 Scientific American
The teenager's brain has a lot of developing to do: It must transform from the brain of a child into the brain of an adult. Some researchers worry how marijuana might affect that crucial process. "Actually, in childhood our brain is larger," says , director of the brain imaging and neuropsychology lab at University of Wisconsin, Milwaukee. "Then, during the teenage years, our brain is getting rid of those connections that weren't really used, and it prunes back. "It actually makes the brain faster and more efficient." The streamlining process ultimately helps the brain make judgments, think critically and remember what it has learned. Lisdahl says it's a mistake for teenagers to use cannabis. "It's the absolute worst time," she says, because the mind-altering drug can disrupt development. Think of the teen years, she says, as the "last golden opportunity to make the brain as healthy and smart as possible." Lisdahl points to a growing number of that show regular marijuana use — once a week or more — actually changes the structure of the teenage brain, specifically in areas dealing with memory and problem solving. That can affect cognition and academic performance, she says. "And, indeed, we see, if we look at actual grades, that chronic marijuana-using teens do have, on average, one grade point lower than their matched peers that don't smoke pot," Lisdahl says. ©2014 NPR
by Tom Siegfried Max Planck, who shook the world with his discovery of quantum physics, also offered a warning. “One must be careful,” he said, “when using the word, real.” It was good advice. As physicists explored the quantum domain, they found that usual ideas about reality did not apply. Reality in the realm of atoms was nothing like the world of rocks and baseballs and planets, where Newton’s laws of motions ruled with rigor. Among atoms, the rules were more like Olympic ice skating judging, with unpredictable scores. Gradually physicists, engineers and even screenwriters became familiar with quantum weirdness and used it in lasers, computers and movie plots. Quantum reality might be crazy, but it’s our reality, and most scientists, anyway, have become more or less used to it. Nevertheless, Planck’s warning still applies. Perhaps the quantum picture of reality is another illusion, just like Newton’s was. Human insight into nature may not yet have penetrated reality’s ultimate veil. In other words, maybe reality always dresses itself up in Newtonian or Einsteinian or quantum clothing, and science hasn’t yet seen what reality looks like naked. And that might explain why nature has been able to protect so many of its mysteries from science’s prying eyes — mysteries like the identity of dark matter, the math describing quantum gravity, the mechanism underlying consciousness. And whether humans have free will. Maybe reality always dresses itself up in Newtonian or Einsteinian or quantum clothing, and science hasn’t yet seen what reality looks like naked. © Society for Science & the Public 2000 - 2013.
Link ID: 19319 - Posted: 03.04.2014
By Deborah Kotz Glaring gaps persist in medical researchers’ efforts to understand gender differences in common diseases, two decades after the passage of pivotal legislation mandating that more women be included in government-funded clinical trials, concludes a report being released Monday at a women’s health summit in Boston. The authors said research still lags on understanding how treatments for heart disease—the number one killer of women—affect the sexes differently, because women make up only one-third of the participants in clinical trials to test new drugs and medical devices, and most of these studies don’t report results for men and women separately. Women who don’t smoke are, for unknown reasons, three times more likely than non-smoking men to get lung cancer, but they’re still less likely than men to enroll in lung cancer studies, notes the report from Brigham and Women’s Hospital. And twice as many women suffer from depression as men, but fewer than 45 percent of animal studies to better understand anxiety and depression use female lab animals. “Women are now routinely included in clinical trials, but we are far from achieving equity in biomedical research,” said report leader Dr. Paula Johnson, executive director of the Brigham’s Connors Center for Women’s Health and Gender Biology. To address research disparities, the authors recommended that government agencies, drug manufacturers, hospital review boards that approve studies, and medical journal editors institute substantial changes to make women’s health a research priority. © 2014 Boston Globe Media Partners, LLC
Keyword: Sexual Behavior
Link ID: 19318 - Posted: 03.04.2014
By ANDREW POLLACK In the late 1980s, scientists at Osaka University in Japan noticed unusual repeated DNA sequences next to a gene they were studying in a common bacterium. They mentioned them in the final paragraph of a paper: “The biological significance of these sequences is not known.” Now their significance is known, and it has set off a scientific frenzy. The sequences, it turns out, are part of a sophisticated immune system that bacteria use to fight viruses. And that system, whose very existence was unknown until about seven years ago, may provide scientists with unprecedented power to rewrite the code of life. In the past year or so, researchers have discovered that the bacterial system can be harnessed to make precise changes to the DNA of humans, as well as other animals and plants. This means a genome can be edited, much as a writer might change words or fix spelling errors. It allows “customizing the genome of any cell or any species at will,” said Charles Gersbach, an assistant professor of biomedical engineering at Duke University. Already the molecular system, known as Crispr, is being used to make genetically engineered laboratory animals more easily than could be done before, with changes in multiple genes. Scientists in China recently made monkeys with changes in two genes. Scientists hope Crispr might also be used for genomic surgery, as it were, to correct errant genes that cause disease. Working in a laboratory — not, as yet, in actual humans — researchers at the Hubrecht Institute in the Netherlands showed they could fix a mutation that causes cystic fibrosis. But even as it is stirring excitement, Crispr is raising profound questions. Like other technologies that once wowed scientists — like gene therapy, stem cells and RNA interference — it will undoubtedly encounter setbacks before it can be used to help patients. © 2014 The New York Times Company
Keyword: Genes & Behavior
Link ID: 19317 - Posted: 03.04.2014
By LISA FELDMAN BARRETT CAN you detect someone’s emotional state just by looking at his face? It sure seems like it. In everyday life, you can often “read” what someone is feeling with the quickest of glances. Hundreds of scientific studies support the idea that the face is a kind of emotional beacon, clearly and universally signaling the full array of human sentiments, from fear and anger to joy and surprise. Increasingly, companies like Apple and government agencies like the Transportation Security Administration are banking on this transparency, developing software to identify consumers’ moods or training programs to gauge the intent of airline passengers. The same assumption is at work in the field of mental health, where illnesses like autism and schizophrenia are often treated in part by training patients to distinguish emotions by facial expression. But this assumption is wrong. Several recent and forthcoming research papers from the Interdisciplinary Affective Science Laboratory, which I direct, suggest that human facial expressions, viewed on their own, are not universally understood. The pioneering work in the field of “emotion recognition” was conducted in the 1960s by a team of scientists led by the psychologist Paul Ekman. Research subjects were asked to look at photographs of facial expressions (smiling, scowling and so on) and match them to a limited set of emotion words (happiness, anger and so on) or to stories with phrases like “Her husband recently died.” Most subjects, even those from faraway cultures with little contact with Western civilization, were extremely good at this task, successfully matching the photos most of the time. Over the following decades, this method of studying emotion recognition has been replicated by other scientists hundreds of times. In recent years, however, at my laboratory we began to worry that this research method was flawed. In particular, we suspected that by providing subjects with a preselected set of emotion words, these experiments had inadvertently “primed” the subjects — in effect, hinting at the answers — and thus skewed the results. © 2014 The New York Times Company
Link ID: 19316 - Posted: 03.03.2014
by Laura Sanders It truly pains me to bring you tired parents another round of “Is this bad for my baby?” But this week, a new study suggests that some white noise machines designed for babies can produce harmful amounts of sound. Before you despair about trashing your baby’s hearing, please keep in mind that like any study, the results are limited in what they can actually claim. And this one is no exception. I learned the power of white noise when Baby V and I ventured out to meet some new mamas for lunch. As I frantically tried to reverse the ensuing meltdown, another mom came over with her phone. “Try this,” she said as she held up her phone and blasted white noise. Lo and behold, her black magic worked. Instantly, Baby V snapped to attention, stopped screaming and stared wide-eyed at the dark wizardry that is the White Noise Lite app. Since then, I learned that when all else failed, the oscillating fan setting could occasionally jolt Baby V out of a screamfest. In general, I didn’t leave the noise on for long. It was annoying, and more importantly, it stopped working after the novelty wore off. But lots of parents do rely on white noise to soothe their babies and help them sleep through the night. These machines are recommended on top parenting websites by top pediatricians, parenting bloggers and, most convincingly, all of the other parents you know. Use liberally, the Internet experts recommend. To reap the benefits, white noise machines should be played all night long for at least the entire first year, many people think. And don’t be shy: The noise should be louder than you think. © Society for Science & the Public 2000 - 2013
By Ariana Eunjung Cha, Standing in a Wisconsin State Capitol hearing room surrounded by parents hugging their seriously ill children, Sally Schaeffer began to cry as she talked about her daughter. Born with a rare chromosomal disorder, 6-year-old Lydia suffers from life-threatening seizures that doctors haven’t been able to control despite countless medications. The family’s last hope: medical marijuana. Schaeffer, 39, didn’t just ask lawmakers to legalize the drug. She begged. “If it was your child and you didn’t have options, what would you do?” she said during her testimony in Madison on Feb. 12. The representatives were so moved that they introduced a bipartisan bill to allow parents in situations similar to Schaeffer’s to use the drug on their children. Emboldened by stories circulated through Facebook, Twitter and the news media about children with seizure disorders who have been successfully treated with a special oil extract made from cannabis plants, mothers have become the new face of the medical marijuana movement. Similar scenes have been playing out in recent weeks in other states where medical marijuana remains illegal: Oklahoma, Florida, Georgia, Utah, New York, North Carolina, Alabama, Kentucky. The “mommy lobby” has been successful at opening the doors to legalizing marijuana — if only a crack, in some places — where others have failed. In the 1970s and ’80s, mothers were on the other side of the issue, successfully fending off efforts to decriminalize marijuana with heartbreaking stories about how their teenage children’s lives unraveled when they began to use the drug. © 1996-2014 The Washington Post
by Megan Gannon, Live Science News Editor Never before seen in biology, a state of matter called "disordered hyperuniformity" has been discovered in the eye of a chicken. This arrangement of particles appears disorganized over small distances but has a hidden order that allows material to behave like both a crystal and a liquid. The discovery came as researchers were studying cones, tiny light-sensitive cells that allow for the perception of color, in the eyes of chickens. For chickens and other birds that are most active during the daytime, these photoreceptors come in four different color varieties — violet, blue, green and red — and a fifth type for detecting light levels, researchers say. Each type of cone is a different size. These cells are crammed into a single tissue layer on the retina. Many animals have cones arranged in an obvious pattern. Insect cones, for example, are laid out in a hexagonal scheme. The cones in chicken eyes, meanwhile, appear to be in disarray. But researchers who created a computer model to mimic the arrangement of chicken cones discovered a surprisingly tidy configuration. Around each cone is a so-called exclusion region that bars other cones of the same variety from getting too close. This means each cone type has its own uniform arrangement, but the five different patterns of the five different cone types are layered on top of each other in a disorderly way, the researchers say. © 2014 Discovery Communications, LLC.
|By Christie Nicholson Our memories are inaccurate, more than we’d like to believe. And now a study demonstrates one reason: we apparently add current experiences onto memories. Study subjects examined the location of objects on a computer screen against a background of an underwater ocean scene. Researchers then showed the subjects a fresh screen with a different background, this time a photo of farmland. And the subjects had to place an object in the same position it was in on the original screen. And they always placed the object in the wrong position. The researchers then presented three objects on the original ocean background. One was in the original location, another was in the location the subject just chose in the previous task and the third was in a new location. The subject was asked to pick the original location of the object in the original ocean background. And instead of choosing the original correct location, they always picked the position they had chosen. That is, they now believed the position they’d picked on the farm scene was the original position on the ocean background. The study is in the Journal of Neuroscience. [Donna J. Bridge and Joel L. Voss, Hippocampal Binding of Novel Information with Dominant Memory Traces Can Support Both Memory Stability and Change] The researchers note that recent and easily retrievable information “can overwrite what was there to begin with.” Consider that next time you hear eyewitness testimony. © 2014 Scientific American
Keyword: Learning & Memory
Link ID: 19312 - Posted: 03.03.2014
by Clare Wilson More genetic mutations may be needed to give rise to autism in girls than in boys. The finding supports the notion that the female brain is somehow protected against autism, and this may in turn explain why four times as many males have autism than females. Although some cases of autism are associated with one mutation, most are thought to involve several genetic abnormalities. In the past few years, hundreds of mutations have been discovered that can make people more vulnerable to the condition. To see if the mutations affect men and women differently, Sébastien Jacquemont at the University Hospital of Lausanne in Switzerland and colleagues measured the frequency of two different kinds of mutation in 762 families that had a child with autism. Among the children with autism, one class of mutation known as a copy number variation – deletions or duplications of a large chunk of genetic material – was three times more common in girls than in boys. The team also found that substitutions of a single letter of DNA were about one-third more common in affected girls. Jacquemont says this suggests it takes more mutations for autism to arise in girls than in boys. "Females function a lot better than males with similar mutations," he says. The results reflect the "shielding" effect of being female, he says. "There's something that's protecting [their] brain development." A larger, as yet unpublished, study of about 2400 people with autism, conducted as part of the Autism Genome Project - an attempt to sequence the whole genome of 10,000 individuals affected by the condition – has produced similar results, says Joseph Buxbaum of Mount Sinai Hospital in New York. © Copyright Reed Business Information Ltd.
Sara Reardon A flipped mental switch is all it takes to make a fly fall in love — even if its object of desire is a ball of wax. A technique called thermogenetics allows researchers to control fly behaviour by activating specific neurons with heat. Combining the system with techniques that use light to trigger neurons could help to elucidate how different neural circuits work together to control complex behaviours such as courtship. Optogenetics — triggering neurons with light — has been successful in mice but has not been pursued much in flies, says Barry Dickson, a neuroscientist at the Howard Hughes Medical Institute's Janelia Farm Research Campus in Ashburn, Virginia. A fibre-optic cable embedded in a mouse’s brain can deliver light to cells genetically engineered to make light-activated proteins, but flies are too small for these fibre optics. Neither will these cells be activated when the flies are put into an illuminated box, because most wavelengths of visible light cannot penetrate a fly’s exoskeleton. Heat can penetrate the exoskeleton, however. Researchers have already studied fly behaviour by adding a heat-activated protein called TRPA1 to neural circuits that control behaviours such as mating and decision-making. When these flies are placed in a hot box, the TRPA1 neurons begin to fire within minutes and drive the fly’s actions1. But it would be better to trigger the behaviours more quickly. So Dickson’s lab has developed a system called the Fly Mind-Altering Device (FlyMAD), which uses a video camera to track the fly as it moves around in a box. The device then shines an infrared laser at the fly to deliver heat directly to the head. Dickson’s group presented the system last October at the Neurobiology of Drosophila conference at Cold Spring Harbor Laboratory in New York, and he is now submitting the work to a peer-reviewed journal. © 2014 Nature Publishing Group