By NICHOLAS BAKALAR Hepatitis infection may increase the risk for Parkinson’s disease, though the reasons for the link remain unknown. British investigators used records of 100,390 patients hospitalized with various forms of hepatitis or H.I.V. from 1999 to 2011. They compared Parkinson’s incidence in these patients with incidence in more than six million people admitted for medical or surgical conditions like cataracts, knee replacement or varicose veins. The study, in Neurology, found that people with hepatitis B had a 76 percent higher risk of having Parkinson’s, and people with hepatitis C a 51 percent higher risk, than the control group. Those with other forms of hepatitis or H.I.V. had no increased risk. The study was restricted to hospitalized patients, and the authors did not have detailed information about the severity and treatment of the diseases. “We can’t be sure what is underlying this association,” said the lead author, Dr. Julia Pakpoor, a researcher at the University of Oxford. “It could be the treatment for the hepatitis, or it could be that Parkinson’s and hepatitis have common risk factors we haven’t identified.” A different kind of study would be needed, she said, to determine possible mechanisms that might be involved. © 2017 The New York Times Company

Keyword: Parkinsons
Link ID: 23430 - Posted: 03.31.2017

Elle Hunt Inches above the seafloor of Sydney’s Cabbage Tree Bay, with the proximity made possible by several millimetres of neoprene and a scuba diving tank, I’m just about eyeball to eyeball with this creature: an Australian giant cuttlefish. Even allowing for the magnifying effects of the mask snug across my nose, it must be about 60cm (two feet) long, and the peculiarities that abound in the cephalopod family, that includes octopuses and squid, are the more striking writ so large. ADVERTISING Its body – shaped around an internal surfboard-like shell, tailing off into a fistful of tentacles – has the shifting colour of velvet in light, and its W-shaped pupils lend it a stern expression. I don’t think I’m imagining some recognition on its part. The question is, of what? It was an encounter like this one – “at exactly the same place, actually, to the foot” – that first prompted Peter Godfrey-Smith to think about these most other of minds. An Australian academic philosopher, he’d recently been appointed a professor at Harvard. While snorkelling on a visit home to Sydney in about 2007, he came across a giant cuttlefish. The experience had a profound effect on him, establishing an unlikely framework for his own study of philosophy, first at Harvard and then the City University of New York. The cuttlefish hadn’t been afraid – it had seemed as curious about him as he was about it. But to imagine cephalopods’ experience of the world as some iteration of our own may sell them short, given the many millions of years of separation between us – nearly twice as many as with humans and any other vertebrate (mammal, bird or fish)

Keyword: Evolution; Learning & Memory
Link ID: 23429 - Posted: 03.30.2017

By ALICE CALLAHAN Peruse the infant formula aisle, or check out the options for prenatal nutritional supplements, and you’ll find that nearly all these products boast a “brain nourishing” omega-3 fatty acid called DHA. But despite decades of research, it’s still not clear that DHA in formula boosts brain health in babies, or that mothers need to go out of their way to take DHA supplements. A systematic review of studies published this month by the Cochrane Collaboration concluded there was no clear evidence that formula supplementation with DHA, or docosahexaenoic acid, a nutrient found mainly in fish and fish oil, improves infant brain development. At the same time, it found no harm from adding the nutrient. The findings are consistent with a review of the effects of omega-3 supplements in pregnancy and infancy published by the Agency for Healthcare Research and Quality last fall that found little evidence of benefit. Still, many experts believe there is value in including DHA in formula. “Even if you can’t easily prove it, because it’s hard to prove developmental outcomes, it makes sense to use it,” said Dr. Steven Abrams, a professor of pediatrics at Dell Medical School at the University of Texas at Austin. “It’s probably a good idea to keep it in there, and it’s certainly safe.” During pregnancy and the first few years of life, DHA accumulates in the brain and retina of the eye and plays an important role in neural and vision development. Breast milk contains DHA in varying concentrations, depending on how much is in the mother’s diet, and some DHA can be made in the body from precursor omega-3 fatty acids, although this process is inefficient. © 2017 The New York Times Company

Keyword: Development of the Brain
Link ID: 23428 - Posted: 03.30.2017

Erin Ross The sex of a sea lamprey may be determined by how fast it grows as a larva. Sex is determined by chromosomes in mammals and by temperature in many reptiles. But for sea lampreys — eel-like creatures that dine on blood — the growth rate of their larvae seems to control whether they are male or female. They are the first creatures known to undergo sex determination in this way. Researchers know next to nothing about sex determination in sea lampreys (Petromyzon marinus) and have long been puzzled by the observation that some adult populations are mostly male, and others female. The fish begin their lives as larvae with undifferentiated sexual organs. After a year or so, they develop gonads, and after a few more years — the timing can vary — they metamorphose into adult sucker-mouthed parasites. A team led by biologist Nick Johnson, at the US Geological Survey in Millersburg, Michigan, identified lamprey habitats in and near streams leading to the Great Lakes. Some areas were productive, with lots of food, whereas others were unproductive sites with little food. After taking measures to ensure no wild lamprey were present, they released between 1,500 and 3,000 wire-tagged larval lamprey into each of the study sites. The researchers recaptured the tagged lamprey and checked their sex after the larvae had metamorphosed into adults and migrated upstream. They found that lamprey in productive streams with lots of food were larger, reached maturity earlier and were more likely to be female. But in unproductive sites, smaller, male lamprey dominated, Johnson’s team reports in a paper published on 29 March in Proceedings of the Royal Society B1. © 2017 Macmillan Publishers Limited

Keyword: Sexual Behavior; Evolution
Link ID: 23427 - Posted: 03.30.2017

By Catherine Offord | Recognizing when you’re singing the right notes is a crucial skill for learning a melody, whether you’re a human practicing an aria or a bird rehearsing a courtship song. But just how the brain executes this sort of trial-and-error learning, which involves comparing performances to an internal template, is still something of a mystery. “It’s been an important question in the field for a long time,” says Vikram Gadagkar, a postdoctoral neurobiologist in Jesse Goldberg’s lab at Cornell University. “But nobody’s been able to find out how this actually happens.” Gadagkar suspected, as others had hypothesized, that internally driven learning might rely on neural mechanisms similar to traditional reward learning, in which an animal learns to anticipate a treat based on a particular stimulus. When an unexpected outcome occurs (such as receiving no treat when one was expected), the brain takes note via changes in dopamine signaling. So Gadagkar and his colleagues investigated dopamine signaling in a go-to system for studying vocal learning, male zebra finches. First, the researchers used electrodes to record the activity of dopaminergic neurons in the ventral tegmental area (VTA), a brain region important in reward learning. Then, to mimic singing errors, they used custom-written software to play over, and thus distort, certain syllables of that finch’s courtship song while the bird practiced. “Let’s say the bird’s song is ABCD,” says Gadagkar. “We distort one syllable, so it sounds like something between ABCD and ABCB.” © 1986-2017 The Scientist

Keyword: Hearing; Sexual Behavior
Link ID: 23426 - Posted: 03.30.2017

By Tim Falconer HOUSE OF ANANSI, MAY 2016I’ve spent my career bothering people. As a journalist and author, I hang around and watch what folks do, and I ask too many questions, some better than others. Later, I have follow-up queries and clarification requests, and I bug them for those stats they promised to provide me. But something different happened when I started researching congenital amusia, the scientific term for tone deafness present at birth, for my new book, Bad Singer. The scientists were as interested in me as I was in them. My idea was to learn to sing and then write about the experience as a way to explore the science of singing. After my second voice lesson, I went to the Université de Montréal’s International Laboratory for Brain, Music, and Sound Research (BRAMS). I fully expected Isabelle Peretz, a pioneer in amusia research, to say I was just untrained. Instead, she diagnosed me as amusic. “So this means what?” I asked. “We would love to test you more.” The BRAMS researchers weren’t alone. While still at Harvard’s Music and Neuroimaging Lab, Psyche Loui—who now leads Wesleyan University’s Music, Imaging, and Neural Dynamics (MIND) Lab—identified a neural pathway called the arcuate fasciculus as the culprit of congenital amusia. So I emailed her to set up an interview. She said sure—and asked if I’d be willing to undergo an fMRI scan. And I’d barely started telling my story to Frank Russo, who runs Ryerson University’s Science of Music, Auditory Research, and Technology (SMART) Lab in Toronto, before he blurted out, “Sorry, I’m restraining myself from wanting to sign you up for all kinds of research and figuring what we can do with you.” © 1986-2017 The Scientist

Keyword: Hearing
Link ID: 23425 - Posted: 03.30.2017

Workplace exposure to electromagentic fields is linked to a higher risk of developing the most common form of motor neurone disease. Amyotrophic lateral sclerosis (ALS) is a disease that ravages the body’s nerve cells, leaving people unable to control their bodies. People can die as soon as two years after first experiencing symptoms. “Several previous studies have found that electrical workers are at increased risk of ALS,” says Neil Pearce, at the London School of Hygiene and Tropical Medicine. “We don’t know why the risk is higher, but the two most likely explanations involve either electrical shocks, or ongoing exposure to extremely low frequency magnetic fields.” Now an analysis of data from more than 58,000 men and 6,500 women suggests it is the latter. Roel Vermeulen, at Utrecht University in the Netherlands, and his team found that people whose jobs exposed them to high levels of very low frequency magnetic fields were twice as likely to develop ALS as people who have never had this kind of occupational exposure. Jobs with relatively highe extremely low frequency electromagnetic fields levels include electric line installers, welders, sewing-machine operators, and aircraft pilots, says Vermuelen. “These are essentially jobs where workers are placed in close proximity to appliances that use a lot of electricity.” © Copyright Reed Business Information Ltd.

Keyword: ALS-Lou Gehrig's Disease
Link ID: 23424 - Posted: 03.30.2017

Sarah Boseley Health editor A man who was paralysed from below the neck after crashing his bike into a truck can once again drink a cup of coffee and eat mashed potato with a fork, after a world-first procedure to allow him to control his hand with the power of thought. Bill Kochevar, 53, has had electrical implants in the motor cortex of his brain and sensors inserted in his forearm, which allow the muscles of his arm and hand to be stimulated in response to signals from his brain, decoded by computer. After eight years, he is able to drink and feed himself without assistance. “I think about what I want to do and the system does it for me,” Kochevar told the Guardian. “It’s not a lot of thinking about it. When I want to do something, my brain does what it does.” The experimental technology, pioneered by the Case Western Reserve University in Cleveland, Ohio, is the first in the world to restore brain-controlled reaching and grasping in a person with complete paralysis. For now, the process is relatively slow, but the scientists behind the breakthrough say this is proof of concept and that they hope to streamline the technology until it becomes a routine treatment for people with paralysis. In the future, they say, it will also be wireless and the electrical arrays and sensors will all be implanted under the skin and invisible.

Keyword: Robotics
Link ID: 23423 - Posted: 03.29.2017

Rae Ellen Bichell Exposure to lead as a child can affect an adult decades later, according to a study out Tuesday that suggests a link between early childhood lead exposure and a dip in a person's later cognitive ability and socioeconomic status. Lead in the United States can come from lots of sources: old, peeling paint; contaminated soil; or water that's passed through lead pipes. Before policies were enacted to get rid of lead in gasoline, it could even come from particles in the fumes that leave car tailpipes. "It's toxic to many parts of the body, but in particular in can accumulate in the bloodstream and pass through the blood brain barrier to reach the brain," says the study's first author, Aaron Reuben, a graduate student in clinical psychology at Duke University. Reuben and his colleagues published the results of a long-term study on the lingering effects of lead. Researchers had kept in touch with about 560 people for decades — starting when they were born in Dunedin, New Zealand, in the 1970s, all the way up to the present. As children, the study participants were tested on their cognitive abilities; researchers determined IQ scores based on tests of working memory, pattern recognition, verbal comprehension and ability to solve problems, among other skills. When the kids were 11 years old, researchers tested their blood for lead. (That measurement is thought to be a rough indicator of lead exposure in the few months before the blood draw.) Then, when they turned 38 years old, the cognitive ability of these study participants was tested again. As Reuben and his colleagues write in this week's issue of JAMA, the journal of the American Medical Association, they found a subtle but worrisome pattern in the data. © 2017 npr

Keyword: Development of the Brain; Neurotoxins
Link ID: 23422 - Posted: 03.29.2017

By KATIE THOMAS The Food and Drug Administration approved on Tuesday the first drug to treat a severe form of multiple sclerosis, offering hope to patients who previously had no other options to combat a relentless disease that leads to paralysis and cognitive decline. The federal agency also cleared the drug to treat people with the more common, relapsing form of the disease. “I think that this is a very big deal,” said Dr. Stephen Hauser, the chairman of the neurology department at the University of California, San Francisco, and leader of the steering committee that oversaw the late-stage clinical trials of the drug, ocrelizumab. “The magnitude of the benefits that we’ve seen with ocrelizumab in all forms of M.S. are really quite stunning.” The drug, which will be sold under the brand name Ocrevus by Genentech, showed the most notable results in patients with relapsing multiple sclerosis, appearing to halt progression of the disease with few serious side effects. In patients with the more severe form, primary progressive multiple sclerosis, the drug only modestly slowed patients’ decline, but medical experts described it as an important first step. “This sort of opens the door for us,” said Dr. Fred D. Lublin, who was a crucial investigator for the clinical trial and is director of the Corinne Goldsmith Dickinson Center for Multiple Sclerosis at Mount Sinai Hospital in New York. “Once we open that door, then we do better and better and better. It’s a very encouraging result.” Genentech, which is owned by the Swiss pharmaceutical giant Roche, said Tuesday that it would charge a list price of $65,000 a year, which — though expensive — is 25 percent less than an existing drug, Rebif, that was shown to be clinically inferior to Ocrevus in the two clinical trials that led to Ocrevus’s approval. © 2017 The New York Times Company

Keyword: Multiple Sclerosis; Neuroimmunology
Link ID: 23421 - Posted: 03.29.2017

Amy Maxmen Before his 33-year-old son became bedridden with chronic fatigue syndrome, biochemist Ronald Davis created technologies to analyse genes and proteins faster, better and more cheaply. Now he aims his inventions at a different target: the elusive inner workings of his son’s malady. In his office at the Stanford Genome Technology Center in Palo Alto, California, Davis holds a nanofabricated cube the size of a gaming die. It contains 2,500 electrodes that measure electrical resistance to evaluate the properties of human cells. When Davis exposed immune cells from six people with chronic fatigue syndrome to a stressor — a splash of common salt — the cube revealed that they couldn’t recover as well as cells from healthy people could. Now his team is fabricating 100 more devices to repeat the experiment, and testing a cheaper alternative — a paper-thin nanoparticle circuit that costs less than a penny to make on an inkjet printer. Davis’s findings, although preliminary, are helping to propel research on chronic fatigue syndrome, also called myalgic encephalomyelitis (ME/CFS), into the scientific mainstream. Physicians used to dismiss the disease as psychosomatic, but studies now suggest that it involves problems in the chemical reactions, or pathways, within cells. “We now have a great deal of evidence to support that this is not only real, but a complex set of disorders,” says Ian Lipkin, an epidemiologist at Columbia University in New York City. “We are gathering clues that will lead to controlled clinical trials.” © 2017 Macmillan Publishers Limited,

Keyword: Depression; Neuroimmunology
Link ID: 23420 - Posted: 03.29.2017

By Kate Yandell In a 1971 paper published in Science, biologist Roger Payne, then at Rockefeller University, and Scott McVay, then an administrator at Princeton University, described the “surprisingly beautiful sounds” made by humpback whales (Megaptera novaeangliae; Science, 173:585-97). Analyzing underwater recordings made by a Navy engineer, the duo found that these whale sounds were intricately repetitive. “Because one of the characteristics of bird songs is that they are fixed patterns of sounds that are repeated, we call the fixed patterns of humpback sounds ‘songs,’” they wrote. OCEAN SONGS: Humpback whales make diverse, broadband sounds that travel miles through the ocean. Their function, however, remains somewhat murky.PLOS ONE, dx.doi.org/10.1371/journal.pone.0079422, 2013 It’s now clear that, in addition to simpler calls, several baleen whale species—including blue, fin, and bowhead—make series of sounds known as song. Humpback song is the most complex and by far the best studied. Units of humpback songs form phrases, series of similar phrases form themes, and multiple themes form songs. All the males in a given population sing the same song, which evolves over time. When whale groups come into contact, songs can spread. But why do whales sing? “The short answer is, we don’t know,” says Alison Stimpert, a bioacoustician at Moss Landing Marine Laboratories in California. Humpback songs are only performed by males and are often heard on breeding grounds, so the dominant hypothesis is that these songs are a form of courtship. The quality of a male’s performance could be a sign of his fitness, for example. But female whales do not tend to approach singing males. Alternatively, whale researchers have proposed that the male whales sing to demarcate territory or to form alliances with other males during mating season. © 1986-2017 The Scientist

Keyword: Sexual Behavior; Hearing
Link ID: 23419 - Posted: 03.29.2017

By Erik Vance The world’s smallest arachnid, the Samoan moss spider, is at a third of a millimeter nearly invisible to the human eye. The largest spider in the world is the goliath birdeater tarantula, which weighs 5 ounces and is about the size of a dinner plate. For reference, that is about the same difference in scale between that same tarantula and a bottlenose dolphin. And yet the bigger spider does not act in more complex ways than its tiny counterpart. “Insects and spiders and the like—in terms of absolute size—have among the tiniest brains we’ve come across,” says William Wcislo, a scientist at the Smithsonian Tropical Research Institute in Panama City. “But their behavior, as far as we can see, is as sophisticated as things that have relatively large brains. So then there’s the question: How do they do that?” No one would argue that a tarantula is as smart as a dolphin or having a really big brain is not an excellent way to perform complicated tasks. But a growing number of scientists are asking the question: Is it the only way? Do you need a big brain to hunt elusive prey, design complicated structures or produce complex social dynamics? For generations scientists have wondered how intelligent creatures developed large brains to perform complicated tasks. But Wcislo is part of a small community of scientists less interested in how brains have grown than how they have shrunk and yet shockingly still perform tasks as well or better than similar species that are much larger in size. In other words, it’s what scientists call brain miniaturization, not unlike the scaling down in size of the transistors in a computer chip. This research, in fact, may hold clues to innovative design strategies that engineers might incorporate in future generations of computers. © 2017 Scientific American

Keyword: Miscellaneous
Link ID: 23418 - Posted: 03.29.2017

Laurel Hamers SAN FRANCISCO — Millennials, rejoice: A winking-face emoji is worth a slew of ironic words. The brain interprets irony or sarcasm conveyed by an emoji in the same way as it does verbal banter, researchers reported March 26 in San Francisco at the Cognitive Neuroscience Society’s annual meeting. Researchers measured brain electrical activity of college students reading sentences ending in various emojis. For example, the sentence “You are such a jerk” was followed by an emoji that matched the words’ meaning (a frowning face), contradicted the words (a smiling face) or implied sarcasm (a winking face). Then the participants assessed the veracity of the sentence—was the person actually a jerk? Some participants read the sentence literally no matter what, said Benjamin Weissman, a linguist at the University of Illinois at Urbana-Champaign. But people who said emojis influenced their interpretation showed different brain activity in response to sentences with a winking emoji than ones with other emojis. A spike in electrical activity occurred 200 milliseconds after reading winky-face sentences, followed by another spike at 600 milliseconds. A similar electrical pattern has been noted in previous studies in which people listened to sentences where intonation conveyed a sarcastic rather than literal interpretation of the words. That peak at 600 milliseconds has been linked to reassessment. It’s as if the brain reads the sentence one way, sees the emoji and then updates its interpretation to fit the new information, Weissman said. |© Society for Science & the Public 2000 - 2017

Keyword: Emotions
Link ID: 23417 - Posted: 03.29.2017

By Lizzie Wade Ask any biologist what makes primates special, and they’ll tell you the same thing: big brains. Those impressive noggins make it possible for primates from spider monkeys to humans to use tools, find food, and navigate the complex relationships of group living. But scientists disagree on what drove primates to evolve big brains in the first place. Now, a new study comes to an unexpected conclusion: fruit. “The paper is enormously valuable,” says Richard Wrangham, a biological anthropologist at Harvard University who was not involved in the work. For the last 20 years, many scientists have argued that primates evolved bigger brains to live in bigger groups, an idea known as the “social brain hypothesis.” The new study’s large sample size and robust statistical methods suggest diet and ecology deserve more attention, Wrangham says. But not everyone is convinced. Others say that although a nutrient-rich diet allows for bigger brains, it wouldn’t be enough by itself to serve as a selective evolutionary pressure. When the authors compare diet and social life, “they’re comparing apples and oranges,” says Robin Dunbar, an evolutionary psychologist at the University of Oxford in the United Kingdom and one of the original authors of the social brain hypothesis. Alex DeCasien, the new study’s author, didn’t set out to shake up this decades-long debate. The doctoral student in biological anthropology at New York University in New York City wanted to tease out whether monogamous primates had bigger or smaller brains than more promiscuous species. She collected data about the diets and social lives of more than 140 species across all four primate groups—monkeys, apes, lorises, and lemurs—and calculated which features were more likely to be associated with bigger brains. To her surprise, neither monogamy nor promiscuity predicted anything about a primate’s brain size. Neither did any other measure of social complexity, such as group size. The only factor that seemed to predict which species had larger brains was whether their diets were primarily leaves or fruit, DeCasien and her colleagues report today in Nature Ecology & Evolution. © 2017 American Association for the Advancement of Science

Keyword: Evolution; Genes & Behavior
Link ID: 23416 - Posted: 03.28.2017

By MATT RICHTEL LOS ANGELES — Nine days after Nikolas Michaud’s latest heroin relapse, the skinny 27-year-old sat on a roof deck at a new drug rehabilitation clinic here. He picked up a bong, filled it with a pinch of marijuana, lit the leaves and inhaled. All this took place in plain view of the clinic’s director. “The rules here are a little lax,” Mr. Michaud said. In almost any other rehab setting in the country, smoking pot would be a major infraction and a likely cause for being booted out. But here at High Sobriety — the clinic with a name that sounds like the title of a Cheech and Chong comeback movie — it is not just permitted, but part of the treatment. The new clinic is experimenting with a concept made possible by the growing legalization of marijuana: that pot, rather than being a gateway into drugs, could be a gateway out. A small but growing number of pain doctors and addiction specialists are overseeing the use of marijuana as a substitute for more potent and dangerous drugs. Dr. Mark Wallace, chairman of the division of pain medicine in the department of anesthesia at the University of California, San Diego, said over the last five years he has used marijuana to help several hundred patients transition off opiates. “The majority of patients continue to use it,” he said of marijuana. But he added that they tell him of the opiates: “I feel like I was a slave to that drug. I feel like I have my life back.” Dr. Wallace is quick to note that his evidence is anecdotal and more study is needed. Research in rats, he said, supports the idea that the use of cannabinoids can induce withdrawal from heavier substances. But in humans? © 2017 The New York Times Company

Keyword: Drug Abuse
Link ID: 23415 - Posted: 03.28.2017

By Des Bieler Brain injuries are a danger in many sports, but for none more than football and its most profitable enterprise, the National Football League. The NFL is spending hundreds of millions of dollars on a concussion-lawsuit settlement and has poured tens of millions into research on measuring and preventing head trauma. Now some scientists are using an NFL-backed technology to examine blood samples for proteins that have been shown to correlate with concussion and other injuries. One of the most intriguing of these proteins, which could help create better tests for traumatic brain injury, is called neurofilament light — or, as it’s known for short, NFL. That’s right, a protein called “NFL” may wind up helping the NFL address its most vexing medical problem. “It's just a remarkable coincidence,” said Kevin Hrusovsky, chief executive of Quanterix, a company that has received $800,000 in grant money from the NFL through the league's “Head Health Challenge” partnership with GE. Quanterix's technology allows users to zero in on molecules with such precision that Hrusovsky likened it to “being able to see a grain of sand in 2,000 Olympic-size swimming pools.” That is crucial, because only tiny amounts of the proteins, referred to as “biomarkers,” dribble across the blood-brain barrier from the cerebrospinal fluid around the brain, where they would be found in larger quantities. The ability to spot sub-concussion injuries is important because they often go undetected by conventional methods and yet are increasingly seen as major threats to long-term health. The problem with simply sampling athletes' cerebrospinal fluid, of course, is that requires a lumbar puncture, or spinal tap, which is a lot to ask in the middle of a football game (or in any other time and place, for that matter). Pricking an athlete's finger for a blood test and getting the results 15 to 20 minutes later makes for a much more reasonable process, albeit one still a long way from implementation. © 1996-2017 The Washington Post

Keyword: Brain Injury/Concussion
Link ID: 23414 - Posted: 03.28.2017

By RONI CARYN RABIN Television ads for “low T” have sparked a rise in the use of testosterone gels, patches and injections by older men in recent years, according to a new report. But anyone hoping that a dose of testosterone will provide an easy antidote for sagging muscles, flagging energy and a retiring sex drive may find the results of recent government studies of the sex hormone sobering. The latest clinical trials, published over the past year, are the first rigorous ones to assess the potential beneficial effects of testosterone treatment for older men with abnormally low levels of the hormone. Scientists followed 790 men age 65 and older who had blood testosterone levels below 275 nanograms per deciliter of blood, well below the average for healthy young men and lower than would be expected with normal aging. The men also had symptoms reflecting their low hormone levels, like loss of sex drive. Half the participants were treated with testosterone gel, and half were given a placebo gel. The studies reported mixed results, finding that over the yearlong study period, testosterone therapy corrected anemia, or low levels of red blood cells, which can cause fatigue, and increased bone density. But a study to see if testosterone improved memory or cognitive function found no effects. Meanwhile, a red flag warning of possible risks to the heart emerged from the studies: Imaging tests found a greater buildup of noncalcified plaque in the coronary arteries of men treated with testosterone for a year, an indicator of cardiac risk, compared with those who were given a placebo gel. The findings of plaque were not a complete surprise; many reports have tied testosterone use to an increase in heart attacks, and the Food and Drug Administration already requires testosterone products to carry warnings of an increased risk of heart attacks and stroke (men at high risk of cardiovascular disease were not allowed to participate in the latest trials). But observational studies, which are weaker, have yielded mixed results over all, with one study published last month finding that men taking testosterone actually had fewer heart problems. © 2017 The New York Times Company

Keyword: Hormones & Behavior; Sexual Behavior
Link ID: 23413 - Posted: 03.28.2017

By C. CLAIBORNE RAY Q. When four of us shared memories of our very young lives, not one of us could recall events before the age of 4 or possibly 3. Is this common? A. Yes. For adults, remembering events only after age 3½ or 4 is typical, studies have found. The phenomenon was named childhood amnesia by Freud and identified late in the 19th century by the pioneering French researcher Victor Henri and his wife, Catherine. The Henris published a questionnaire on early memories in 1895, and the results from 123 people were published in 1897. Most of the participants’ earliest memories came from when they were 2 to 4 years old; the average was age 3. Very few participants recalled events from the first year of life. Many subsequent studies found similar results. Several theories have been offered to explain the timing of laying down permanent memories. One widely studied idea relates the formation of children’s earliest memories to when they start talking about past events with their mothers, suggesting a link between memories and the age of language acquisition. More recent studies, in 2010 and 2014, found discrepancies in the accuracy of young children’s estimates of when things had occurred in their lives. Another 2014 study found a progressive loss of recall as a child ages, with 5-, 6- and 7-year-olds remembering 60 percent or more of some early-life events that were discussed at age 3, while 8- and 9-year-olds remembered only 40 percent of these events. © 2017 The New York Times Company

Keyword: Learning & Memory; Development of the Brain
Link ID: 23412 - Posted: 03.28.2017

Laurel Hamers SAN FRANCISCO — When faced with simple math problems, people who get jittery about the subject may rely more heavily on certain brain circuitry than math-savvy people do. The different mental approach could help explain why people with math anxiety struggle on more complicated problems, researchers reported March 25 at the Cognitive Neuroscience Society’s annual meeting. While in fMRI machines, adults with and without math anxiety evaluated whether simple arithmetic problems, such as 9+2=11, were correct or incorrect. Both groups had similar response times and accuracy on the problems, but brain scans turned up differences. Specifically, in people who weren’t anxious about math, lower activation of the frontoparietal attention network was linked to better performance. That brain network is involved in working memory and problem solving. Math-anxious people showed no correlation between performance and frontoparietal network activity. People who used the circuit less were probably getting ahead by automating simple arithmetic, said Hyesang Chang, a cognitive neuroscientist at the University of Chicago. Because math-anxious people showed more variable brain activity overall, Chang speculated that they might instead be using a variety of computationally demanding strategies. This scattershot approach works fine for simple math, she said, but might get maxed out when the math is more challenging. Citations H. Chang et al. Simple arithmetic: Not so simple for highly math anxious individuals. Cognitive Neuroscience Society Annual Meeting, San Francisco, March 25, 2017. |© Society for Science & the Public 2000 - 2017.

Keyword: Attention; Emotions
Link ID: 23411 - Posted: 03.28.2017