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Jo Marchant The brain cells of people with Parkinson’s disease can be trained to reliably respond to placebo drugs, Italian neuroscientists report. The training wears off after 24 hours but the effect shows it may be possible to reduce the medication needed to treat Parkinson’s by interspersing real drugs with inert injections or pills, says placebo researcher Fabrizio Benedetti at the University of Turin, Italy, who led the work. A few people with Parkinson’s disease do respond dramatically to placebos, but most do not1. People with the condition suffer characteristic tremors and stiff muscles because their dopamine-producing brain cells are gradually dying off. They alleviate their symptoms by taking drugs such as apomorphine, which activate receptors for dopamine. For some conditions — such as pain and immune disorders — trials have shown2 that it is possible to train people to respond to placebos, although this practice hasn’t made its way into clinical care. Benedetti and his colleagues wondered whether the same effect might be possible for neurological disorders. They studied 42 people with advanced Parkinson’s disease who were having electrodes implanted into their brains for a therapy called deep brain stimulation, which eases symptoms by stimulating affected brain areas directly. That surgery gave Benedetti’s team a rare opportunity to measure the activity of individual neurons in the thalamus, a brain region known to be inhibited by lack of dopamine in people with Parkinson's. © 2016 Nature Publishing Grou

Keyword: Parkinsons
Link ID: 21884 - Posted: 02.10.2016

By CARL ZIMMER The Zika virus has quickly gained Ebola-level notoriety as it has spread through the Western Hemisphere in recent months. Researchers in Brazil, where it was first detected in May, have linked infections in pregnant women to a condition known as microcephaly: infants born with undersize heads. Where birth defects are concerned, however, the Zika virus is far from unique. A number of other viruses, such as rubella and cytomegalovirus, pose a serious risk during pregnancy. Researchers have uncovered some important clues about how those pathogens injure fetuses — findings that are now helping to guide research into the potential link between Zika and microcephaly. “I think we’ll discover a lot of parallels,” said Dr. Mark R. Schleiss, the director of pediatric infectious diseases and immunology at the University of Minnesota Medical School. The risk that viruses pose during pregnancy came to light in the mid-1900s, when outbreaks of rubella, or German measles, led to waves of birth defects, including microcephaly, cataracts and deformed hearts and livers. The number of infants affected was staggering. In an epidemic in Philadelphia in 1965, 1 percent of all babies were born with congenital rubella syndrome, which can also cause deafness, developmental disability, low birth weight and seizures. Because of vaccinations, such devastation is now rare in the United States and a number of other countries. “I’m 52, and I’ve seen one case of congenital rubella syndrome,” said Dr. David W. Kimberlin, a professor of pediatrics at the University of Alabama at Birmingham. But the virus is still a grave threat in developing countries. Worldwide, more than 100,000 children are born each year with congenital rubella syndrome. © 2016 The New York Times Company

Keyword: Development of the Brain
Link ID: 21883 - Posted: 02.10.2016

By Jordana Cepelewicz Seasonal variations play a major role in the animal kingdom—in reproduction, food availability, hibernation, even fur color. Whether this seasonality has such a significant influence on humans, however, is an open question. Its best-known association is with mood—that is, feeling down during the colder months and up in the summer—and, in extreme cases, seasonal depression, a phenomenon known as seasonal affective disorder (SAD). A new study published in this week’s Proceedings of the National Academy of Sciences seeks to delve deeper into how human biology has adapted not only to day/night cycles (circadian rhythms) but to yearly seasonal patterns as well. Scientists have previously found seasonal variation in the levels and concentrations of certain compounds associated with mood (including dopamine and serotonin), conception and even mortality. Now for the first time, using functional MRI, “it’s [been] conclusively shown that cognition and the brain’s means of cognition are seasonal,” says neuroscientist Gilles Vandewalle of the University of Liège in Belgium, the study’s lead researcher. These findings come at a time when some scientists are disputing the links between seasonality and mental health. Originally aiming to investigate the impact of sleep and sleep deprivation on brain function, Vandewalle and his fellow researchers placed 28 participants on a controlled sleep/wake schedule for three weeks before bringing them into the laboratory, where they stayed for 4.5 days. During this time they underwent a cycle of sleep deprivation and recovery in the absence of seasonal cues such as natural light, time information and social interaction. Vandewalle’s team repeated the entire procedure with the same subjects several times throughout the course of nearly a year and a half. © 2016 Scientific American

Keyword: Attention; Biological Rhythms
Link ID: 21882 - Posted: 02.10.2016

By Michelle Roberts Health editor, Exposure to short flashes of light at night could help sleeping travellers adjust to new time zones and avoid jet lag, according to US scientists. The light beams travel through the eyelids and this tells the brain to re-set the body's inner biological clock, the Stanford researchers believe. They tested the method in 39 volunteers and found it shifted a person's body clock by about two hours. An hour of the flashlight therapy was enough to achieve this effect. People's bodies synchronise to the 24-hour pattern of daytime and night they are used to. And when they travel across time zones to a new light-dark schedule, they need to realign. While most people can easily manage a long-haul flight across one or two time zones, crossing several time zones messes with the body clock. Jet lag can leave travellers tired, irritable and disorientated for days. As a remedy, some people take melatonin tablets, which mimic a hormone released in the evening. Some try phototherapy - light boxes that simulate daylight. But Dr Jamie Zeitzer and colleagues at Stanford University School of Medicine believe sleeping in front of a strobe light could work better. They asked volunteers to go to bed and wake up at the same times every day for about two weeks. Next, they were asked to sleep in the lab, where some were exposed to continuous light and others a strobe light (two-millisecond flashes of light, similar to a camera flash, 10 seconds apart) for an hour. The flashing-light group reported a nearly two-hour delay in the onset of sleepiness the following night. In comparison, the delay in sleepiness was 36 minutes for the continuous-light group. Dr Zeitzer calls his therapy "biological hacking". Cells in the back of the eye that detect the light send messages to a part of the brain that sets the body clock. The light fools the brain into thinking the day is longer than it really is, which shifts the inner clock. © 2016 BBC.

Keyword: Biological Rhythms
Link ID: 21881 - Posted: 02.10.2016

Ice cream lovers, look away now. Studies on a simulated human gut have added further evidence that emulsifiers, found in most processed foods, might be linked to obesity, diabetes and inflammatory bowel disorders. Emulsifiers are used to improve a food’s texture and to prevent mixtures from separating, particularly in ice cream. Last year, Benoit Chassaing of Georgia State University showed that mice that drank water containing one of two emulsifiers underwent changes in gut bacteria and inflammation of the gut – changes that led to obesity and diabetes in these animals. However, mice that didn’t have any gut bacteria because they had been raised in a sterile environment didn’t become ill when given the same additives, suggesting that it is the emulsifiers’ effect on the microbiome that is to blame. When the ill mice stopped consuming emulsifiers, their gut bacteria gradually returned to normal. The question is whether the same might be true for humans. The growing use of emulsifiers has coincided with a rise in obesity and diabetes, says Chassaing, while these conditions aren’t as common in countries where less processed food is consumed. Now Chassaing has supported his findings in mice using a simulation of the human gut. Working with a team in Belgium, he looked at two emulsifiers: carboxymethylcellulose (E566 on EU labels) and polysorbate-80 (E433). When added to a series of flasks that mimic the conditions of the human digestive tract, each caused an increase in the levels of a bacterial protein called flagellin, known to cause inflammation at high concentrations. Chassaing presented the results at a recent meeting at the Royal Society in London. © Copyright Reed Business Information Ltd.

Keyword: Obesity
Link ID: 21880 - Posted: 02.10.2016

By Nicholas Bakalar Eating seafood is linked to a reduced risk of dementia-associated brain changes in people who carry the ApoE4 gene variation, which increases the risk for Alzheimer’s disease. Eating seafood was not linked to similar changes in those who carried other forms of the ApoE gene. The study, published in JAMA, looked at 286 autopsied brains and also found that eating seafood was linked to increased mercury in the brain, but that mercury levels were not linked to brain abnormalities. After controlling for age, sex, education and other factors, the researchers found that compared with those who ate less seafood, ApoE4 carriers who had one seafood meal or more a week had lower densities of the amyloid plaques and neurofibrillary tangles typical of Alzheimer’s disease. Over all, they had a 47 percent lower likelihood of having a post-mortem diagnosis of Alzheimer’s. Consumption of fish oil supplements was not correlated with pathological brain changes. The lead author, Martha Clare Morris, a professor of epidemiology at Rush University, said that mercury from fish appears to pose little risk for aging people. But, she said, there are studies that show that mercury consumption in pregnancy can cause cognitive problems in babies. “Most studies in dementia have found that one seafood meal a week is beneficial,” she said, though “they haven’t found that the more you eat, the lower the risk.” © 2016 The New York Times Company

Keyword: Alzheimers
Link ID: 21879 - Posted: 02.10.2016

By Virginia Morell Like fearful humans, horses raise the inner brow of their eyes when threatened or surprised. Altogether their faces can convey 17 emotions (ours express 27), and they readily recognize the expressions on their fellow equines. But can they read our facial cues? To find out, researchers tested 28 horses, including 21 geldings and seven mares, from stables in the United Kingdom. Each horse was led by his/her halter rope to a position in the stable, and then presented with a life-size color photograph of the face of a man. The man was either smiling or frowning angrily. The scientists recorded the animals’ reactions, and measured their heart rates. Other studies have shown that stressed horses’ heart rates fluctuate, and when the horses looked at the angry man, their hearts reached a maximum heart rate more quickly than when they viewed the smiling image. When shown the angry face, 20 of the horses also turned their heads so that they could look at it with their left eye—a response that suggests they understood the expression, the scientists report online today in Biology Letters, because the right hemisphere of the brain is specialized for processing negative emotions. Dogs, too, have this “left-gaze bias” when confronting angry faces. Also, like dogs, the horses showed no such bias, such as moving their heads to look with the right eye, when viewing the happy faces—perhaps because the animals don’t need to respond to nonthreatening cues. But an angry expression carries a warning—the person may be about to strike. The discovery that horses as well as dogs—the only two animals this has been tested in—can read our facial expressions spontaneously and without training suggests one of two things: Either these domesticated species devote a lot of time to learning our facial cues, or the ability is innate and more widespread in the animal kingdom than previously thought. © 2016 American Association for the Advancement of Scienc

Keyword: Attention; Evolution
Link ID: 21878 - Posted: 02.10.2016

By John Bohannon Didn't get your 40 winks last night? Better not get yourself arrested, or you may admit to a crime you didn't commit. False confessions are surprisingly easy to extract from people simply by keeping them awake, according to a new study of sleep deprivation. It puts hard numbers to a problem that criminal law reformers have worried about for decades. The “crime” in question took place in a sleep lab run by Kimberly Fenn at Michigan State University in East Lansing. Together, she and Elizabeth Loftus, a psychologist at the University of California (UC), Irvine, and two of their former Ph.D. students recruited 88 Michigan State students to take part in an experiment. During two separate visits, the students worked at computers solving problems and filling out questionnaires. They were all given a stern warning: Do not press the escape key, because it will erase important study data. After their second session, the subjects were split into two groups. Half of them were forced to stay awake all night under the watch of the researchers. Scrabble, TV shows, and a card game called euchre seemed to do the trick. The rest were allowed to get a full night's sleep. But that also required policing. "We actually had a student leave the study because he wanted to stay awake all night to study for an exam the next day," Fenn says, adding that "I certainly do not advocate this!" The next morning, everyone received a typed statement describing their performance. The statement accused them of hitting the escape key on the first day, even though none of them actually did so—the computers recorded all keystrokes. © 2016 American Association for the Advancement of Science

Keyword: Sleep; Attention
Link ID: 21877 - Posted: 02.09.2016

Bruce Bower Winter doesn’t deserve its dour reputation as the season of depression, scientists say. Rates of major depression, a psychiatric condition marked by intense sadness, hopelessness, insomnia and a general loss of interest or pleasure, don’t markedly change from one season to another among U.S. adults, says a team led by psychologist Steven LoBello of Auburn University at Montgomery in Alabama. Neither do symptoms intensify or become more numerous during winter among those already suffering from depression, the researchers report online January 19 in Clinical Psychological Science. A small number of people with regular fall or winter depression may have gone undetected in the new study, which surveyed more than 30,000 U.S. adults. Still, it’s becoming harder to justify the current psychiatric diagnosis of major depression “with seasonal pattern,” LoBello and Auburn colleagues Megan Traffanstedt and Sheila Mehta conclude. Because it’s a recurring disorder, depression can strike in two consecutive winters by chance, the researchers say. Depression in three or more consecutive winters could be due to personal and social factors unrelated to shorter days, they add. “Being depressed during winter is not evidence that one is depressed because of winter,” LoBello says. © Society for Science & the Public 2000 - 2016

Keyword: Depression; Biological Rhythms
Link ID: 21876 - Posted: 02.09.2016

By Jordana Cepelewicz As the Panthers and Broncos faced off in the third quarter of last night’s Super Bowl, wide receiver Philly Brown suffered a possible concussion—and to the disappointment of Panthers fans, he never returned to the game. But for good reason: concussions are now known to be much more serious injuries than once thought. And the danger may not be limited to the immediate repercussions. Researchers have already linked more severe traumatic brain injury to later suicide—particularly in military veterans and professional athletes—and have more recently explored the connection between concussion and depression. Now, new research published in the Canadian Medical Association Journal shows that even mild concussions sustained in ordinary community settings might be more detrimental than anyone anticipated; the long-term risk of suicide increases threefold in adults if they have experienced even one concussion. That risk increases by a third if the concussion is sustained on a weekend instead of a weekday—suggesting recreational concussions are riskier long-term than those sustained on the job. “The typical patient I see is a middle-aged adult, not an elite athlete,” says Donald Redelmeier, a senior scientist at the University of Toronto and one of the study’s lead authors. “And the usual circumstances for acquiring a concussion are not while playing football; it is when driving in traffic and getting into a crash, when missing a step and falling down a staircase, when getting overly ambitious about home repairs—the everyday activities of life.” Redelmeier and his team wanted to examine the risks of the concussions acquired under those circumstances. © 2016 Scientific American

Keyword: Brain Injury/Concussion; Depression
Link ID: 21875 - Posted: 02.09.2016

By Steven Petrow I have slogged through a number of difficult situations in recent months, among them the ongoing crises of my elderly parents’ illnesses and the suicide of a friend. I never lost my appetite nor burst into tears, and I didn’t suffer from any of the other typical symptoms of depression. Maybe I was more irritable than usual, a bit more prone to snap. And yes, I buried myself in my work. But I didn’t think I’d tripped down into the rabbit hole of depression. You would think I would have been more self-aware, both personally and professionally. As a health journalist, I have often used my own stories to write about difficult-to-discuss medical conditions, including learning I had testicular cancer at age 26 and my misdiagnosis with H.I.V./AIDS — back when it was a death sentence. But I had never written about suffering from depression, even though it’s plagued me since I first put pen to paper, at age 11, when I started keeping a diary. Still, I’m far from alone. At least six million men in the United States suffer from depression, according to the National Institute of Mental Health. The true number is likely to be even higher, said Dr. Matthew Rudorfer, the institute’s associate director for treatment research, since men are less likely than women to report classic symptoms like low mood, sadness or crying, so they often go undiagnosed. Men, he told me, more often demonstrate “externalizing” symptoms like irritability, anger and aggressiveness, substance and alcohol abuse, risk-taking behaviors and “workaholism.” Oh, that macho thing: Men don’t get depressed; they just work, drink and compete harder. Andrew Solomon, author of the pathbreaking memoir about depression, “Noonday Demon,” told me that ridiculous attitude is part of the mind-set that guys should “cover up our moods with militarism or athleticism.” © 2016 The New York Times Company

Keyword: Depression
Link ID: 21874 - Posted: 02.09.2016

By NATALIE ANGIER Whether to enliven a commute, relax in the evening or drown out the buzz of a neighbor’s recreational drone, Americans listen to music nearly four hours a day. In international surveys, people consistently rank music as one of life’s supreme sources of pleasure and emotional power. We marry to music, graduate to music, mourn to music. Every culture ever studied has been found to make music, and among the oldest artistic objects known are slender flutes carved from mammoth bone some 43,000 years ago — 24,000 years before the cave paintings of Lascaux. Given the antiquity, universality and deep popularity of music, many researchers had long assumed that the human brain must be equipped with some sort of music room, a distinctive piece of cortical architecture dedicated to detecting and interpreting the dulcet signals of song. Yet for years, scientists failed to find any clear evidence of a music-specific domain through conventional brain-scanning technology, and the quest to understand the neural basis of a quintessential human passion foundered. Now researchers at the Massachusetts Institute of Technology have devised a radical new approach to brain imaging that reveals what past studies had missed. By mathematically analyzing scans of the auditory cortex and grouping clusters of brain cells with similar activation patterns, the scientists have identified neural pathways that react almost exclusively to the sound of music — any music. It may be Bach, bluegrass, hip-hop, big band, sitar or Julie Andrews. A listener may relish the sampled genre or revile it. No matter. When a musical passage is played, a distinct set of neurons tucked inside a furrow of a listener’s auditory cortex will fire in response. Other sounds, by contrast — a dog barking, a car skidding, a toilet flushing — leave the musical circuits unmoved. Nancy Kanwisher and Josh H. McDermott, professors of neuroscience at M.I.T., and their postdoctoral colleague Sam Norman-Haignere reported their results in the journal Neuron. The findings offer researchers a new tool for exploring the contours of human musicality. © 2016 The New York Times Company

Keyword: Hearing; Brain imaging
Link ID: 21873 - Posted: 02.09.2016

It’s well known that some people report that their mood is influenced by the seasons. But can the time of year affect other cognitive functions? To find out, Gilles Vandewalle and colleagues at the University of Liege in Belgium scanned the brains of 28 volunteers while they performed attention and working memory tests at different times of the year. To ensure the results were influenced by the seasons rather than the environmental conditions on the test day, the participants were confined to a lab for 4.5 days prior to the test, exposed to a constant light level and temperature. Although their test scores didn’t change with the seasons, activity in some brain areas showed a consistent seasonal pattern among the volunteers: brain activity peaked in the summer on the attention task and in the autumn on the memory task. Many seasonally changing factors could regulate such a pattern, including day length (known as photoperiod), temperature, humidity, social interaction and physical activity. Since these weren’t all controlled for in the study, it’s impossible to say what is responsible for the seasonal changes seen. “In our data it seems that photoperiod, or the rate of change of photoperiod, was more likely to explain what we were seeing. But we can’t exclude all the others,” says Vandewalle. The results suggest that over the course of a year, the brain might work in different ways to compensate for seasonal factors that could affect its function, enabling it to maintain a stable performance. Vandewalle speculates that these mechanisms might not work as well in some people, for example, those vulnerable to the winter blues. © Copyright Reed Business Information Ltd.

Keyword: Depression; Learning & Memory
Link ID: 21872 - Posted: 02.09.2016

Laura Sanders A preliminary report from scientists at the biotech company Amgen Inc. questions a cancer drug’s ability to fight Alzheimer’s disease. In experiments described February 4 in F1000Research, bexarotene, a drug approved by the FDA to treat lymphoma, didn’t reduce levels of the Alzheimer’s-related amyloid-beta protein. In the original work, described in Science in 2012 (SN: 3/10/12, p. 5), neuroscientist Gary Landreth of Case Western Reserve University in Cleveland and colleagues showed that bexarotene swiftly clears A-beta from the brains of mice, reducing both the sticky plaques and smaller forms of the protein that circulate in the brain. The mice also showed signs of improved learning and memory. A year after that work appeared, four reports, also in Science, disputed some of those findings. In tests on rats, the Amgen scientists found that bexarotene didn’t drop levels of plaques or smaller forms of A-beta. The new study didn’t describe behavioral tests. Landreth points out that this study, and previous experiments that failed to find a benefit, used a formulation of the drug that wouldn’t persist at high enough levels in the brain to be useful. “The controversy with the preclinical data is going to go away in the face of solid clinical trials,” Landreth says. A small clinical trial published online January 29 in Alzheimer’s Research & Therapy found that bexarotene reduced A-beta in the brains of people, but only people without a particular version of the ApoE gene, a known risk factor for Alzheimer’s. © Society for Science & the Public 2000 - 2016

Keyword: Alzheimers
Link ID: 21871 - Posted: 02.09.2016

By Jesse Singal On paper, Dr. Kenneth Zucker isn’t the sort of person who gets suddenly and unceremoniously fired. For decades, the 65-year-old psychologist had led the Child Youth and Family Gender Identity Clinic (GIC), in Toronto, one of the most well-known clinics in the world for children and adolescents with gender dysphoria — that is, the feeling that the body they were born with doesn’t fit their true gender identity. Zucker had built up quite a CV during his time leading the clinic: In addition to being one of the most frequently cited names in the research literature on gender dysphoria and gender-identity development, and the editor of the prestigious journal Archives of Sexual Behavior, he took a leading role helping devise diagnostic and treatment guidelines for gender dysphoric and transgender individuals. He headed the group which developed the DSM-5’s criteria for its “gender dysphoria” entry, for example, and also helped write the most recent “standards of care” guidelines for the World Professional Association for Transgender Health — one of the bibles for clinicians who treat transgender and gender-dysphoric patients. An impressive career, yes, but it’s doubtful any of this gave him much comfort on December 15. That was when he was called in from vacation for an 8:30 a.m. meeting with his employer, the Centre for Addiction and Mental Health (CAMH), one of the largest mental health and addiction research hospitals in Canada. Given the long-brewing investigation of his clinic by the hospital, it’s unlikely Zucker was feeling optimistic about what awaited him in downtown Toronto. The GIC, which operates out of CAMH, pronounced “Cam-H,” had been standing firm against a changing tide in the world of psychological treatment for children with gender dysphoria. The “gender-affirmative” approach, which focuses on identifying young transgender children and helping them socially transition — that is, express their gender to others through their everyday clothes, name changes, or other means — has been on the rise in recent years, and has become the favored protocol of many activists and clinicians. GIC clinicians, who saw clients between ages 3 and 18, had a much more cautious stance on social transitioning for their younger clients — they believed that in many cases, it was preferable to first “help children feel comfortable in their own bodies,” as they often put it, since in the GIC’s view gender is quite malleable at a young age and gender dysphoria will likely resolve itself with time. © 2016, New York Media LLC

Keyword: Sexual Behavior; Development of the Brain
Link ID: 21870 - Posted: 02.08.2016

By RACHEL NUWER For all the havoc that zebra mussels, Asian carp, round gobies and dozens of other alien species have wrought on the Great Lakes, those waters have never known a foe like the sea lamprey. The vampirelike parasites cost many millions each year in depleted fisheries and eradication efforts. Wildlife managers have long used lampricide — the lamprey version of pesticide — with mixed results. Now, an innovative control program seeks to improve on that method by using pheromones to trick the bloodsuckers into voluntarily corralling themselves in designated areas, to then be trapped or poisoned. But achieving this depends on cracking the fish’s olfactory language. “The broad goal is to understand how this animal makes decisions,” said Michael Wagner, a fish ecologist at Michigan State University. “Then, we want to use that understanding to guide lampreys’ movements by manipulating the landscape of fear and opportunity.” Lampreys look like the stuff of horror films: a slithering, tubular body topped with a suction-cup mouth ringed with row upon row of hooked yellow teeth. With this mouth, a sea lamprey anchors to its fish prey and uses its rasping tongue to drill into the victim’s flesh. It remains there for up to a month, feeding on blood and body fluids. Even if a fish survives the attack, the gaping wound left behind often results in death. In their natural ranges, lampreys are important components of food webs. The problems begin only when they shift from native to invader. Sea lampreys slipped into Lake Ontario through the Erie Canal in the mid-19th century, and then made it past Niagara Falls around 1919 with the renovation of the Welland Canal. In the lakes, lampreys found a utopia: no predators, and bountiful prey that had no natural defenses against their voracious appetites. Biological disaster ensued. © 2016 The New York Times Company

Keyword: Chemical Senses (Smell & Taste)
Link ID: 21869 - Posted: 02.08.2016

Floaters, those small dots or cobweb-shaped patches that move or “float” through the field of vision, can be alarming. Though many are harmless, if you develop a new floater, “you need to be seen pretty quickly” by an eye doctor in order to rule out a retinal tear or detachment, said Dr. Rebecca Taylor, a spokeswoman for the American Academy of Ophthalmology. Floaters are caused by clumping of the vitreous humor, the gel-like fluid that fills the inside of the eye. Normally, the vitreous gel is anchored to the back of the eye. But as you age, it tends to thin out and may shrink and pull away from the inside surface of the eye, causing clumps or strands of connective tissue to become lodged in the jelly, much as “strands of thread fray when a button comes off on your coat,” Dr. Taylor said. The strands or clumps cast shadows on the retina, appearing as specks, dots, clouds or spider webs in your field of vision. Such changes may occur at younger ages, too, particularly if you are nearsighted or have had a head injury or eye surgery. There is no treatment for floaters, though they usually fade with time. But it’s still important to see a doctor if new floaters arise because the detaching vitreous gel can pull on the retina, causing it to tear, which can lead to retinal detachment, a serious condition. The pulling or tugging on the retina may be perceived as lightning-like flashes, “like a strobe light off to the side of your vision,” Dr. Taylor said. See an eye doctor within 24 to 48 hours if you have a new floater, experience a sudden “storm” of floaters, see a gray curtain or shadow move across your field of vision, or have a sudden decrease in vision. © 2016 The New York Times Company

Keyword: Vision
Link ID: 21868 - Posted: 02.08.2016

Laura Sanders The brain can bounce back after a single head hit, but multiple hits in quick succession don’t give the brain time to recover, a new study suggests. Although the finding comes from mice, it may help scientists better understand the damage caused by repetitive impacts such as those sustained in football, soccer and other contact sports. The results, published in the March issue of the American Journal of Pathology, hint that a single, mild head hit isn’t necessarily cause for alarm. “There are things to be afraid of after a concussion,” says study coauthor Mark Burns of Georgetown University Medical Center in Washington, D.C. “But not every concussion is going to cause long-term damage.” Burns and his colleagues subjected some mice to a single, mild head hit. The relatively weak hit consistently slowed anesthetized mice’s return to consciousness, but didn’t cause major trauma. The impact was designed to mimic a mild traumatic brain injury, or concussion, in a person. Tests a day after the impact showed that about 13 percent of dendritic spines, docking sites that help connect brain cells, had vanished in a particular part of the brain. Three days after the injury, these missing connections reappeared, even surpassing the original number of connections. This fluctuating number of dendritic spines may actually help the brain recover, Burns says. “The cells weren’t dying,” he says. “They were responding to the injury.” © Society for Science & the Public 2000 - 2016.

Keyword: Brain Injury/Concussion
Link ID: 21867 - Posted: 02.06.2016

By Jeneen Interlandi The human brain’s memory-storage capacity is an order of magnitude greater than previously thought, researchers at the Salk Institute for Biological Studies reported last week. The findings, recently detailed in eLife, are significant not only for what they say about storage space but more importantly because they nudge us toward a better understanding of how, exactly, information is encoded in our brains. The question of just how much information our brains can hold is a longstanding one. We know that the human brain is made up of about 100 billion neurons, and that each one makes 1,000 or more connections to other neurons, adding up to some 100 trillion in total. We also know that the strengths of these connections, or synapses, are regulated by experience. When two neurons on either side of a synapse are active simultaneously, that synapse becomes more robust; the dendritic spine (the antenna on the receiving neuron) also becomes larger to support the increased signal strength. These changes in strength and size are believed to be the molecular correlates of memory. The different antenna sizes are often compared with bits of computer code, only instead of 1s and 0s they can assume a range of values. Until last week scientists had no idea how many values, exactly. Based on crude measurements, they had identified just three: small, medium and large. But a curious observation led the Salk team to refine those measurements. In the course of reconstructing a rat hippocampus, an area of the mammalian brain involved in memory storage, they noticed some neurons would form two connections with each other: the axon (or sending cable) of one neuron would connect with two dendritic spines (or receiving antennas) on the same neighboring neuron, suggesting that duplicate messages were being passed from sender to receiver. © 2016 Scientific American

Keyword: Learning & Memory
Link ID: 21866 - Posted: 02.06.2016

Colombia says three people have died after contracting the Zika virus and developing a rare nerve disorder. Health Minister Alejandro Gaviria said there was a "causal connection" between Zika, the Guillain-Barre disorder and the three deaths. Earlier, Brazilian scientists said they had detected for the first time active samples of Zika in urine and saliva. However, it is not clear whether the virus can be transmitted through bodily fluids. Zika, a mosquito-borne disease, has been linked to cases of babies born in Brazil with microcephaly - underdeveloped brains. "We have confirmed and attributed three deaths to Zika," said the head of Colombia's National Health Institute, Martha Lucia Ospina. "In this case, the three deaths were preceded by Guillain-Barre syndrome." Guillain-Barre is a rare disorder in which the body's immune system attacks part of the nervous system. It isn't normally fatal. Ms Ospina said another six deaths were being investigated for possible links to Zika. "Other cases (of deaths linked to Zika) are going to emerge," she said. "The world is realising that Zika can be deadly. The mortality rate is not very high, but it can be deadly." Mr Gaviria said one of the fatalities took place in San Andres and the other two in Turbo, in Antioquia department. UK virologist Prof Jonathan Ball, of the University of Nottingham, told the BBC: "We have been saying Zika has been associated with Guillain-Barre. One of the complications of that could be respiratory failure. But it is still probably a very rare event." Although Zika usually causes mild, flu-like symptoms, it has been linked to thousands of suspected birth defects. However, it has not yet been proved that Zika causes either microcephaly or Guillain-Barre. © 2016 BBC

Keyword: Movement Disorders; Neuroimmunology
Link ID: 21865 - Posted: 02.06.2016