Most Recent Links
Follow us on Facebook and Twitter, or subscribe to our mailing list, to receive news updates. Learn more.
By Ruth Williams The offspring of certain mice fed a high-fat diet have altered gut microbiomes and may be prone to autism-like behaviors including social deficits, according to a study published today (June 16) in Cell. But treating these offspring with a specific microbial species they lack can rectify the animals’ social behavior. “There’s growing evidence that the microbiome, particularly early in life, can have long-term effects on brain development and behavior,” said anatomist and neuroscientist John Cryan of University College Cork in Ireland who was not involved in the study. “What this paper does is take advantage of the fact that we get our microbiome from our mums, and looks at what happens if the mum disturbs her microbiome during pregnancy.” According to the US Centers for Disease Control and Prevention, one in 68 U.S. children have autism spectrum disorder (ASD). Recent evidence suggests that the risk of ASD is increased for the offspring of mothers with obesity. In both humans and non-human primates, the offspring of obese mothers have also been shown to have abnormal microbiomes. And some people with ASD have imbalanced gut microbes, or dysbiosis. Baylor College of Medicine’s Mauro Costa-Mattioli and colleagues sought to better understand how maternal obesity, the microbiome, and ASD are interconnected. The team turned to mice for answers. The researchers gave female animals high-fat diets before setting up matings, later finding that a “large proportion” of the offspring exhibited ASD-like behaviors, including reduced social interaction, repetitive behaviors, and anxiety. The team analyzed the microbiomes of these offspring, finding that they differed from those of control animals. © 1986-2016 The Scientist
Link ID: 22336 - Posted: 06.18.2016
Lisa Fine Jess Thom says the word "biscuit" about 16,000 times every day. Her brother-in-law counted once. That's just one of the tics that Thom, a London-based performance artist, has to manage as part of her life with Tourette's syndrome, a neurological disorder characterized by involuntary vocal or motor tics. Specialists say the condition affects as many as 300,000 children in the United States, though many are undiagnosed. Thom has had tics since childhood, but she wasn't diagnosed until her 20s. "What disables me ... is other people's misunderstanding," she says. "What's exciting is that it's something we all have power to change." The condition is far more common than many people realize, and many misperceptions about it still exist, says Kevin McNaught, executive vice president of the advocacy group Tourette Association of America. "It's not a rare disorder," McNaught says, citing an estimated 1 in 100 school-age children with the condition, including many who aren't diagnosed until adulthood, if at all. Michael Chichioco, a California high school senior who has Tourette's syndrome, says he used to be bullied at school, with kids trying to trigger him to have outbursts. His tics come out more prominently when he is nervous or excited. © 2016 npr
Link ID: 22335 - Posted: 06.18.2016
By Tanya Lewis The human brain may wind down when asleep, but it doesn’t lose all responsiveness. Researchers from the École Normale Supérieure in Paris and their colleagues recently used electroencephalography (EEG) to monitor the brains of volunteers listening to recordings of spoken words, which they were asked to classify as either objects or animals. Participants were able to classify words during light non-REM (NREM) sleep, but not during either deep NREM sleep or REM sleep, according to a study published today (June 14) in The Journal of Neuroscience. “With an elegant experimental design and sophisticated analyses of neural activity, [the authors] demonstrate the extent to which the sleeping brain is able to process sensory information, depending on sleep depth [or] stage,” Thomas Schreiner of the University of Fribourg in Switzerland, who was not involved in the study, wrote in an email to The Scientist. During sleep, the brain is thought to block out external stimuli through a gating mechanism at the level of the thalamus. But experiments dating back to the 1960s have shown that certain types of stimuli, such as hearing one’s name, can filter through and trigger awakening. However, the mechanisms that allow the brain to selectively take in information during sleep remain unknown. “When we fall asleep, it’s pretty similar to a coma because we lose consciousness of our self and of the [outside] world,” study coauthor Thomas Andrillon, a neuroscientist at the École Normale Supérieure, told The Scientist. The question was “whether the brain could still monitor what was going on around, just to be sure the environment was still safe,” he added. © 1986-2016 The Scientist
By Karen Weintraub Many people think they can teach themselves to need less sleep, but they’re wrong, said Dr. Sigrid Veasey, a professor at the Center for Sleep and Circadian Neurobiology at the University of Pennsylvania’s Perelman School of Medicine. We might feel that we’re getting by fine on less sleep, but we’re deluding ourselves, Dr. Veasey said, largely because lack of sleep skews our self-awareness. “The more you deprive yourself of sleep over long periods of time, the less accurate you are of judging your own sleep perception,” she said. Multiple studies have shown that people don’t functionally adapt to less sleep than their bodies need. There is a range of normal sleep times, with most healthy adults naturally needing seven to nine hours of sleep per night, according to the National Sleep Foundation. Those over 65 need about seven to eight hours, on average, while teenagers need eight to 10 hours, and school-age children nine to 11 hours. People’s performance continues to be poor while they are sleep deprived, Dr. Veasey said. Extended vacations are the best times to assess how much sleep you truly need. Once you catch up on lost sleep and are not sleep deprived, the amount you end up sleeping is a good measure how much you need every night. You can ask yourself the questions, “Do you feel that your brain is much sharper, your temper is better, you’re paying attention more effectively? If those answers are yes, than definitely get the sleep,” said Dr. Veasey, who realized -- to her chagrin -- that she needs nine hours of sleep a night to function effectively. Health issues like pain, sleep apnea or autoimmune disease can increase people's need for sleep, said Andrea Meredith, a neuroscientist at the University of Maryland School of Medicine. © 2016 The New York Times Company
Link ID: 22333 - Posted: 06.18.2016
In a study of stroke patients, investigators confirmed through MRI brain scans that there was an association between the extent of disruption to the brain’s protective blood-brain barrier and the severity of bleeding following invasive stroke therapy. The results of the National Institutes of Health-funded study were published in Neurology. These findings are part of the Diffusion and Perfusion Imaging Evaluation for Understanding Stroke Evolution (DEFUSE)-2 Study, which was designed to see how MRIs can help determine which patients undergo endovascular therapy following ischemic stroke caused by a clot blocking blood flow to the brain. Endovascular treatment targets the ischemic clot itself, either removing it or breaking it up with a stent. The blood-brain barrier is a layer of cells that protects the brain from harmful molecules passing through the bloodstream. After stroke, the barrier is disrupted, becoming permeable and losing control over what gets into the brain. “The biggest impact of this research is that information from MRI scans routinely collected at a number of research hospitals and stroke centers can inform treating physicians on the risk of bleeding,” said Richard Leigh, M.D., a scientist at NIH’s National Institute of Neurological Disorders and Stroke (NINDS) and an author on the study. In this study, brain scans were collected from more than 100 patients before they underwent endovascular therapy, within 12 hours of stroke onset. Dr. Leigh and his team obtained the images from DEFUSE-2 investigators.
Alva Noë Sometimes the mind wanders. Thoughts pop into consciousness. Ideas or images are present when just a moment before they were not. Scientists recently have been turning their attention to making sense of this. One natural picture of the phenomenon goes something like this. Typically, our thoughts and feelings are shaped by what we are doing, by what there is around us. The world captures our attention and compels our minds this way or that. What explains the fact that you think of a red car when there is a red car in front of you is, well, the red car. And similarly, it is that loud noise that causes you to orient yourself to the commotion that is producing it. In such cases, we might say, the mind is coupled to the world around it and the world, in a way, plays us the way a person might play a piano. But sometimes, even without going to sleep, we turn away from the world. We turn inward. We are contemplative or detached. We decouple ourselves from the environment and we are set free, as it were, to let our minds play themselves. This natural picture has gained some support from the discovery of the so-called Default Mode Network. The DMN is a network of neural systems whose activation seems to be suppressed by active engagement with the world around us; DMN, in contrast, is activated (or rather, it tends to return to baseline levels of activity) precisely when we detach ourselves from what's going on around us. The DMN is the brain running in neutral. One of the leading hypotheses to explain mind-wandering and the emergence of spontaneous thoughts is that this is the result of the operation of the brain's Default Mode Network. (See this for a review of this literature.) © 2016 npr
Link ID: 22331 - Posted: 06.18.2016
Laura Sanders If you want to lock new information into your brain, try working up a sweat four hours after first encountering it. This precisely timed trick, described June 16 in Current Biology, comes courtesy of 72 people who learned the location of 90 objects on a computer screen. Some of these people then watched relaxing nature videos, while others worked up a sweat on stationary bikes, alternating between hard and easy pedaling for 35 minutes. This workout came either soon after the cram session or four hours later. Compared with both the couch potatoes and the immediate exercisers, the people who worked out four hours after their learning session better remembered the objects’ locations two days later. The delayed exercisers also had more consistent activity in the brain’s hippocampus, an area important for memory, when they remembered correctly. That consistency indicates that the memories were stronger, Eelco van Dongen of the Donders Institute in the Netherlands and colleagues propose. The researchers don’t yet know how exercise works its memory magic, but they have a guess. Molecules sparked by aerobic exercise, including the neural messenger dopamine and the protein BDNF, may help solidify memories by reorganizing brain cell connections. Citations E. van Dongen et al. Physical exercise performed four hours after learning improves memory retention and increases hippocampal pattern similarity during retrieval. Current Biology. Published online June 16, 2016. doi: 10.1016/j.cub.2016.04.071. © Society for Science & the Public 2000 - 2016
Keyword: Learning & Memory
Link ID: 22330 - Posted: 06.18.2016
Ian Sample Science editor Brain scans have highlighted “striking” differences between the brains of young men with antisocial behavioural problems and those of their better-behaved peers. The structural changes, seen as variations in the thickness of the brain’s cortex or outer layer of neural tissue, may result from abnormal development in early life, scientists at Cambridge University claim. But while the images show how the two groups of brains differ on average, the scans cannot be used to identify individuals with behavioural issues, nor pinpoint specific developmental glitches that underpin antisocial behaviour. Led by Luca Passamonti, a neurologist at Cambridge, the researchers scanned the brains of 58 young men aged 16 to 21 who had been diagnosed with conduct disorder, defined by persistent problems that ranged from aggressive and destructive behaviour, to lying and stealing, carrying weapons or staying out all night. When compared with brain scans from 25 healthy men of the same age, the scientists noticed clear differences. Those diagnosed with conduct disorder before the age of 10 had similar variations in the thickness of the brain’s cortex. “It may be that problems they experience in childhood affect and delay the way the cortex is developing,” said Passamonti. But the brains of men diagnosed with behavioural problems in adolescence differed in another way. Scans on them showed fewer similarities in cortical thickness than were seen in the healthy men. That, Passamonti speculates, may arise when normal brain maturation, such as the “pruning” of neurons and the connections between them, goes awry. © 2016 Guardian News and Media Limited
By Aleszu Bajak Can the various puzzles and quizzes associated with commercial brain-training games really improve cognitive function — or better yet, stave off cognitive decline? To date, the scientific evidence is murky, but that hasn’t kept companies from trying to cash-in on consumers’ native desire for quick fixes to complex health problems. The most famous among such companies is probably Lumosity, a product of San Francisco-based Lumos Labs, which once marketed its suite of web-based games and mobile apps as being “built on proven neuroscience,” and by encouraging users to “harness your brain’s neuroplasticity and train your way to a brighter life.” Exercising your brain with online brain-training games like Lumosity (above) or Smart Brain Aging sounds like a great idea, but the science is still murky. Exercising your brain with online brain-training games like Lumosity (above) or Smart Brain Aging sounds like a great idea, but the science is still murky. Those claims were among several that attracted the attention of the Federal Trade Commission, which earlier this year filed a complaint against the company. Lumosity was ultimately slapped with $50 million in fines for deceiving consumers — although $48 million of that was reportedly suspended by a district court, because the company was financially unable to pay the full amount. “Lumosity preyed on consumers’ fears about age-related cognitive decline, suggesting their games could stave off memory loss, dementia, and even Alzheimer’s disease,” said Jessica Rich, Director of the FTC’s Bureau of Consumer Protection, in a statement accompanying the settlement. “But Lumosity simply did not have the science to back up its ads.” Copyright 2016 Undark
By Clare Wilson Pass the sick bag. A device that allows people to empty a portion of their stomach contents into a toilet after a meal has just got the go-ahead from the US Food and Drug Administration. The device is approved for use by people who are severely obese, defined as having a body mass index of over 35 kg/m2. The stomach-churning device, which is already available in some European countries, involves a tube being placed into the stomach in a short surgical procedure. The end of the tube contains a valve that lies flush against the skin. Normally it is kept closed, but after meals, the person can connect the valve to another tube to drain about a third of their partially digested food into the toilet. It cannot remove more food than this, because the end of the internal tube is positioned higher than most of the stomach’s contents. Manufacturer Aspire Bariatrics, based in Pennsylvania, says users need to chew their food well and eat more slowly to stop the 6 millimetre tube from getting blocked, and that this in itself helps reduce overeating. “You get some solid chunks,” says Kathy Crothall, head of Aspire Bariatrics. “If a patient doesn’t chew their food very carefully they won’t get anything out of this device.” The device, called AspireAssist, has a safety feature within the valve that means it can only be used three times a day for up to six weeks. After this time it stops working and part of the device must be replaced. © Copyright Reed Business Information Ltd.
Link ID: 22327 - Posted: 06.16.2016
Susan Milius The Nyctibatrachus humayuni frogs live only in India’s Western Ghats, a region of still-unexplored biodiversity. Video now shows that the mating male of the species positions himself loosely on a female’s back, with his hands on the ground or leaves. From this position, called a dorsal straddle, the male then releases sperm directly onto the female’s back. Then, in an unusual move, he retreats before she lays the eggs. Sperm trickling down the female’s back and legs fertilize the eggs, an international research team reports June 14 in PeerJ. It’s the first time biologists have documented this loose straddling position. More typically, male frogs, which don’t deliver sperm into a female reproductive tract, hold tight and contact freshly deposited eggs to fertilize them. Bombay night frogs do on occasion crawl over their eggs, but researchers found the eggs are already fertilized. Biologists studying the challenges of external fertilization have previously cataloged six basic forms of male frog mating grasp, or amplexus. Four take some kind of back-hug approach or a head straddle. Other species position themselves rump-to-rump or, in what’s called glued amplexus, with the male dangling from a behemoth female. Position is hardly the only unexpected feature of courting Bombay night frogs. Females give courtship croaks, one of only a few dozen female-vocal species among the 6,500-plus known kinds of frogs. © Society for Science & the Public 2000 - 2016
Keyword: Sexual Behavior
Link ID: 22326 - Posted: 06.16.2016
By Gretchen Reynolds Physical activity is good for our brains. A wealth of science supports that idea. But precisely how exercise alters and improves the brain remains somewhat mysterious. A new study with mice fills in one piece of that puzzle. It shows that, in rodents at least, strenuous exercise seems to beneficially change how certain genes work inside the brain. Though the study was in mice, and not people, there are encouraging hints that similar things may be going on inside our own skulls. For years, scientists have known that the brains of animals and people who regularly exercise are different than the brains of those who are sedentary. Experiments in animals show that, for instance, exercise induces the creation of many new cells in the hippocampus, which is a part of the brain essential for memory and learning, and also improves the survival of those fragile, newborn neurons. Researchers believe that exercise performs these feats at least in part by goosing the body’s production of a substance called brain-derived neurotropic factor, or B.D.N.F., which is a protein that scientists sometimes refer to as “Miracle-Gro” for the brain. B.D.N.F. helps neurons to grow and remain vigorous and also strengthens the synapses that connect neurons, allowing the brain to function better. Low levels of B.D.N.F. have been associated with cognitive decline in both people and animals. Exercise increases levels of B.D.N.F. in brain tissue. But scientists have not understood just what it is about exercise that prompts the brain to start pumping out additional B.D.N.F. So for the new study, which was published this month in the journal eLIFE, researchers with New York University’s Langone Medical Center and other institutions decided to microscopically examine and reverse engineer the steps that lead to a surge in B.D.N.F. after exercise. They began by gathering healthy mice. Half of the animals were put into cages that contained running wheels. The others were housed without wheels. For a month, all of the animals were allowed to get on with their lives. Those living with wheels ran often, generally covering several miles a day, since mice like to run. The others remained sedentary. © 2016 The New York Times Company
Megan Scudellari Shinya Yamanaka looked up in surprise at the postdoc who had spoken. “We have colonies,” Kazutoshi Takahashi said again. Yamanaka jumped from his desk and followed Takahashi to their tissue-culture room, at Kyoto University in Japan. Under a microscope, they saw tiny clusters of cells — the culmination of five years of work and an achievement that Yamanaka hadn't even been sure was possible. Two weeks earlier, Takahashi had taken skin cells from adult mice and infected them with a virus designed to introduce 24 carefully chosen genes. Now, the cells had been transformed. They looked and behaved like embryonic stem (ES) cells — 'pluripotent' cells, with the ability to develop into skin, nerve, muscle or practically any other cell type. Yamanaka gazed at the cellular alchemy before him. “At that moment, I thought, 'This must be some kind of mistake',” he recalls. He asked Takahashi to perform the experiment again — and again. Each time, it worked. Over the next two months, Takahashi narrowed down the genes to just four that were needed to wind back the developmental clock. In June 2006, Yamanaka presented the results to a stunned room of scientists at the annual meeting of the International Society for Stem Cell Research in Toronto, Canada. He called the cells 'ES-like cells', but would later refer to them as induced pluripotent stem cells, or iPS cells. “Many people just didn't believe it,” says Rudolf Jaenisch, a biologist at the Massachusetts Institute of Technology in Cambridge, who was in the room. But Jaenisch knew and trusted Yamanaka's work, and thought it was “ingenious”. © 2016 Macmillan Publishers Limited,
By Ashley P. Taylor Sleep is known to aid memory and learning. For example, people who learn something, sleep on it, and are tested on the material after they wake up tend to perform better than those who remain awake in the interim. Within that general phenomenon, however, there’s a lot of unexplained variation. University of California, Riverside, sleep researcher Sara Mednick wondered “what else might be going during that sleep period that helps people’s memories,” she told The Scientist. As it turns out, activity of the autonomic nervous system (ANS) explains a large part of this variation, Mednick and colleagues show in a paper published today (June 13) in PNAS. The researchers measured not only the electrical activity of the brain during sleep, but also that of the heart, providing an indicator of ANS activity. They found that the beat-to-beat variation in heart rate accounted for much of the previously unexplained variation in how well people performed on memory and creativity tests following a nap. “There is a good possibility that this additional measure [heart-rate variability] may help account for discrepant findings in the sleep-dependent memory consolidation literature,” sleep and cognition researcher Rebecca Spencer of the University of Massachusetts, Amherst, who was not involved in the work, wrote in an email. “Perhaps we put too large of a focus on sleep physiology from the CNS [central nervous system] and ignore a significant role of the ANS.” © 1986-2016 The Scientist
By Brady Dennis In one city after another, the tests showed startling numbers of children with unsafe blood lead levels: Poughkeepsie and Syracuse and Buffalo. Erie and Reading. Cleveland and Cincinnati. In those cities and others around the country, 14 percent of kids — and in some cases more — have troubling amounts of the toxic metal in their blood, according to new research published Wednesday. The findings underscore how despite long-running public health efforts to reduce lead exposure, many U.S. children still live in environments where they're likely to encounter a substance that can lead to lasting behavioral, mental and physical problems. "We've been making progress for decades, but we have a ways to go," said Harvey Kaufman, senior medical director at Quest Diagnostics and a co-author of the study, which was published in the Journal of Pediatrics. "With blood [lead] levels in kids, there is no safe level." Kaufman and two colleagues at Quest, the nation's largest lab testing provider, examined more than 5.2 million blood tests for infants and children under age 6 that were taken between 2009 and 2015. The results spanned every state and the District of Columbia. The researchers found that while blood lead levels declined nationally overall during that period, roughly 3 percent of children across the country had levels that exceed five micrograms per deciliter — the threshold that the Centers for Disease Control and Prevention considers cause for concern. But in some places and among particular demographics, those figures are much higher.
By NATALIE ANGIER At birth, the least weasel is as small and light as a paper clip, and the tiny ribs that press visibly against its silvery pink skin give it a segmented look, like that of an insect. A newborn kit is exceptionally underdeveloped, with sealed eyes and ears that won’t open for five or six weeks, an age when puppies and kittens are ready to be weaned. A mother weasel, it seems, has no choice but to deliver her young half-baked. As a member of the mustelid clan — a noble but often misunderstood family of carnivorous mammals that includes ferrets, badgers, minks and wolverines — she holds to a slender, elongated body plan, the better to pursue prey through tight spaces that most carnivores can’t penetrate. Bulging baby bumps would jeopardize that sylphish hunting physique. The solution? Give birth to the equivalent of fetuses and then finish gestating them externally on mother’s milk. “If you want access to small environments, you can’t have a big belly,” said William J. Zielinski, a mustelid researcher with the United States Forest Service in Arcata, Calif. “You don’t see fat weasels.” For Dr. Zielinski and other mustelid-minded scientists, weasels exemplify evolutionary genius and compromise in equal measure, the piecing together of exaggerated and often contradictory traits to yield a lineage of fierce, fleet, quick-witted carnivores that can compete for food against larger celebrity predators like the big cats, wolves and bears. Researchers admit that wild mustelids can be maddening to study. Most species are secretive loners, shrug off standard radio collars with ease, and run close to the ground “like small bolts of brown lightning,” as one team noted. Now you see them, no, you didn’t. Nevertheless, through a mix of dogged field and laboratory studies, scientists have lately made progress in delineating the weasel playbook, and it’s a page turner, or a page burner. © 2016 The New York Times Company
Link ID: 22321 - Posted: 06.14.2016
By Julia Shaw Can you trust your memory? Picture this. You are in a room full of strangers and you are going around introducing yourself. You say your name to about a dozen people, and they say their names to you. How many of these names are you going to remember? More importantly, how many of these names are you going to misremember? Perhaps you call a person you just met John instead of Jack. This kind of thing happens all the time. Now magnify the situation. You are talking to a close friend, and you disclose something important to them, perhaps even something traumatic. You might, for example, say you witnessed the Paris attacks in 2015. But, how can you know for sure that your memory is accurate? Like most people, you probably feel that misremembering someone’s name is totally different from misremembering an important and emotional life event. That you could never forget #JeSuisParis, and will always have stable and reliable memories of such atrocities. I’m sure that is what those who witnessed 9/11, the 7/7 bombings in London or the assassination of JFK also thought. However, when experimenters conduct research on the accuracy of these so-called “flashbulb memories,” they find that many people make grave errors in their recollections of important historical and personal events. And these errors are more than just omissions. © 2016 Scientific American
Keyword: Learning & Memory
Link ID: 22320 - Posted: 06.14.2016
by Laura Sanders Any parent trying to hustle a school-bound kid out the door in the morning knows that her child’s skull possesses a strange and powerful form of black magic: It can repel parents’ voices. Important messages like “find your shoes” bounce off the impenetrable fortress and drift unheeded to the floor. But when this perplexing force field is off, it turns out that mothers’ voices actually have profound effects on kids. Children’s brains practically buzz when they hear their moms’ voices, scientists report in the May 31 Proceedings of the National Academy of Sciences. (Fun and not surprising side note: Babies’ voices get into moms’ brains, too.) The parts of kids’ brains that handle emotions, face recognition and reward were prodded into action by mothers’ voices, brain scans of 24 children ages 7 to 12 revealed. And words were not required to get this big reaction. In the study, children listened to nonsense words said by either their mother or one of two unfamiliar women. Even when the words were fake, mothers’ voices still prompted lots of neural action. The study was done in older kids, but children are known to tune into their mothers’ voices early. Really early, in fact. One study found that fetuses’ heart rates change when they hear their moms read a story. For a fetus crammed into a dark, muffled cabin, voices may take on outsized importance. |© Society for Science & the Public 2000 - 2016.
By Brian Platzer It started in 2010 when I smoked pot for the first time since college. It was cheap, gristly weed I’d had in my freezer for nearly six years, but four hours after taking one hit I was still so dizzy I couldn’t stand up without holding on to the furniture. The next day I was still dizzy, and the next, and the next, but it tapered off gradually until about a month later I was mostly fine. Over the following year I got married, started teaching seventh and eighth grade, and began work on a novel. Every week or so the disequilibrium sneaked up on me. The feeling was one of disorientation as much as dizziness, with some cloudy vision, light nausea and the sensation of being overwhelmed by my surroundings. During one eighth-grade English class, when I turned around to write on the blackboard, I stumbled and couldn’t stabilize myself. I fell in front of my students and was too disoriented to stand. My students stared at me slumped on the floor until I mustered enough focus to climb up to a chair and did my best to laugh it off. I was only 29, but my father had had a benign brain tumor around the same age, so I had a brain scan. My brain appeared to be fine. A neurologist recommended I see an ear, nose and throat specialist. A technician flooded my ear canal with water to see if my acoustic nerve reacted properly. The doctor suspected either benign positional vertigo (dizziness caused by a small piece of bonelike calcium stuck in the inner ear) or Ménière’s disease (which leads to dizziness from pressure). Unfortunately, the test showed my inner ear was most likely fine. But just as the marijuana had triggered the dizziness the year before, the test itself catalyzed the dizziness now. In spite of the negative results, doctors still believed I had an inner ear problem. They prescribed exercises to unblock crystals, and salt pills and then prednisone to fight Ménière’s disease. All this took months, and I continued to be dizzy, all day, every day. It felt as though I woke up every morning having already drunk a dozen beers — some days, depending on how active and stressful my day was, it felt like much more. Most days ended with me in tears. © 2016 The New York Times Company
[Agata Blaszczak-Boxe, Contributing Writer] People who use marijuana for many years respond differently to natural rewards than people who don't use the drug, according to a new study. Researchers found that people who had used marijuana for 12 years, on average, showed greater activity in the brain's reward system when they looked at pictures of objects used for smoking marijuana than when they looked at pictures of a natural reward — their favorite fruits. "This study shows that marijuana disrupts the natural reward circuitry of the brain, making marijuana highly salient to those who use it heavily," study author Dr. Francesca Filbey, an associate professor of behavioral and brain science at the University of Texas at Dallas, said in a statement. "In essence, these brain alterations could be a marker of transition from recreational marijuana use to problematic use." [11 Odd Facts About Marijuana] In the study, researchers looked at 59 marijuana users who had used marijuana daily for the past 60 days, and had used the drug on at least 5,000 occasions during their lives. The researchers wanted to see whether the brains of these long-term marijuana users would respond differently to picures of objects related to marijuana use than they did to natural rewards, such as their favorite fruits, compared with people who did not use marijuana.
Keyword: Drug Abuse
Link ID: 22317 - Posted: 06.14.2016