Chapter 16. None
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By Sarah C. P. Williams Parrots, like the one in the video above, are masters of mimicry, able to repeat hundreds of unique sounds, including human phrases, with uncanny accuracy. Now, scientists say they have pinpointed the neurons that turn these birds into copycats. The discovery could not only illuminate the origins of bird-speak, but might shed light on how new areas of the brain arise during evolution. Parrots, songbirds, and hummingbirds—which can all chirp different dialects, pick up new songs, and mimic sound—all have a “song nuclei” in their brain: a group of interconnected neurons that synchronizes singing and learning. But the exact boundaries of that region are fuzzy; some researchers define it as larger or smaller than others do, depending on what criteria they use to outline the area. And differences between the song nuclei of parrots—which can better imitate complex sounds—and other birds are hard to pinpoint. Neurobiologist Erich Jarvis of Duke University in Durham, North Carolina, was studying the activation of PVALB—a gene that had been previously found in songbirds—within the brains of parrots when he noticed something strange. Stained sections of deceased parrot brains revealed that the gene was turned on at distinct levels within two distinct areas of what he thought was the song nuclei of the birds’ brains. Sometimes, the gene was activated in a spherical central core of the nuclei. But other times, it was only active in an outer shell of cells surrounding that core. When he and collaborators looked more closely, they found that the inner core and the outer shell—like the chocolate and surrounding candy shell of an M&M—varied in many more ways as well.
Patricia Neighmond A report finds mixed results when it comes to how well medical marijuana works to calm pain and control symptoms. And, an editorial says states legalizing pot for medical use may be jumping the gun. DAVID GREENE, HOST: Twenty-three states plus the District of Columbia have approved pot for medical use. But a new study in the Journal of the American Medical Association is raising questions about its safety and effectiveness. Here's NPR's Patti Neighmond. PATTI NEIGHMOND, BYLINE: Researchers from the University of Bristol in the United Kingdom reviewed findings from 79 different studies looking at the effect of marijuana on symptoms ranging from chronic pain to sleep difficulties and mental illness. At best, they found only moderate evidence indicating that marijuana reduced nerve pain and pain from cancer. When it came to other conditions, like nausea and vomiting due to chemotherapy, difficulties sleeping or weight loss among HIV patients, there was some anecdotal evidence suggesting that people may be helped by marijuana, but it was just that - anecdote. D'SOUZA: Which is really the bulk of the evidence that the states have used in approving medical marijuana. NEIGHMOND: In an editorial accompanying this study, Dr. Deepak Cyril D'Souza says states legalizing marijuana for medical use may be jumping the gun before good quality evidence is in. D'SOUZA: If a pharmaceutical company, for example, wanted to get a drug approved for a medical condition and they only submitted anecdotal data, there's absolutely no chance that that drug would be approved. NEIGHMOND: D'Souza is a psychiatrist with Yale University's School of Medicine. For years, he's studied the impact of marijuana on mental health. And the big question, he says, is how routine daily use - the way one might use marijuana to treat a medical condition - affects the body and the brain over the long term. Concerns have been raised about memory loss, panic, paranoia and other severe disorders. © 2015 NPR
Keyword: Drug Abuse
Link ID: 21089 - Posted: 06.25.2015
Sarah Schwartz A person’s sense of smell may reveal a lot about his or her identity. A new test can distinguish individuals based upon their perception of odors, possibly reflecting a person’s genetic makeup, scientists report online June 22 in Proceedings of the National Academy of Sciences. Most humans perceive a given odor similarly. But the genes for the molecular machinery that humans use to detect scents are about 30 percent different in any two people, says neuroscientist Noam Sobel of the Weizmann Institute of Science in Rehovot, Israel. This variation means that nearly every person’s sense of smell is subtly different. Nobody had ever developed a way to test this sensory uniqueness, Sobel says. Sobel and his colleagues designed a sensitive scent test they call the “olfactory fingerprint.” In an experiment, test subjects rated how strongly 28 odors such as clove or compost matched 54 adjectives such as “nutty” or “pleasant.” An olfactory fingerprint describes individuals’ perceptions of odors’ similarities, not potentially subjective scent descriptions. All 89 subjects in the study had distinct olfactory fingerprints. The researchers calculated that just seven odors and 11 descriptors could have identified each individual in the group. With 34 odors, 35 descriptors, and around five hours of testing per person, the scientists estimate they could individually identify about 7 billion different people, roughly the entire human population. © Society for Science & the Public 2000 - 2015.
By Kiona Smith-Strickland Are crows the smartest animals of all? Many scientists think that corvids — the family of birds that includes crows, ravens, rooks and jays — may be among the most intelligent animals on Earth, based on their ability to solve problems, make tools and apparently consider both possible future events and other individuals’ states of mind. “There’s a lot of research that has been done with both ravens and crows because they are such intelligent species,” said Margaret Innes, an assistant curator at the Maryland Zoo in Baltimore. Even in humans, defining and measuring intelligence is difficult, and it’s more complicated in other species, which have very different body shapes and have evolved for their niche in the environment. However, scientists who study cognition have defined a few measures of intelligence: recognizing oneself in a mirror, solving complex problems, making tools, using analogies and symbols, and reasoning about what others are thinking. For a long time, biologists expected most of these mental feats to be unique to primates. The great apes — chimpanzees, orangutans and gorillas — succeed at nearly all of these tasks, from making and using tools to learning large vocabularies of symbols, as well as recognizing themselves in mirrors. A select few other mammals also meet most of the accepted criteria for intelligence. Dogs and dolphins, for instance, are very good at tasks involving social intelligence, such as communication, conflict resolution and reasoning about what others are thinking. Dolphins are also capable of basic tool use — for instance, carrying sea sponges in their mouths to shield their noses from scrapes and bumps as they forage on the ocean floor.
Carl Zimmer Certain people, researchers have discovered, can’t summon up mental images — it’s as if their mind’s eye is blind. This month in the journal Cortex, the condition received a name: aphantasia, based on the Greek word phantasia, which Aristotle used to describe the power that presents visual imagery to our minds. I find research like this irresistible. It coaxes me to think about ways to experience life that are radically different from my own, and it offer clues to how the mind works. And in this instance, I played a small part in the discovery. In 2005, a 65-year-old retired building inspector paid a visit to the neurologist Adam Zeman at the University of Exeter Medical School. After a minor surgical procedure, the man — whom Dr. Zeman and his colleagues refer to as MX — suddenly realized he could no longer conjure images in his mind. Dr. Zeman couldn’t find any description of such a condition in medical literature. But he found MX’s case intriguing. For decades, scientists had debated how the mind’s eye works, and how much we rely on it to store memories and to make plans for the future. MX agreed to a series of examinations. He proved to have a good memory for a man of his age, and he performed well on problem-solving tests. His only unusual mental feature was an inability to see mental images. Dr. Zeman and his colleagues then scanned MX’s brain as he performed certain tasks. First, MX looked at faces of famous people and named them. The scientists found that certain regions of his brain became active, the same ones that become active in other people who look at faces. © 2015 The New York Times Company
Link ID: 21085 - Posted: 06.23.2015
Skinny jeans can seriously damage muscles and nerves, doctors have said. A 35-year-old woman had to be cut out of a pair after her calves ballooned in size, the medics said in the Journal of Neurology, Neurosurgery and Psychiatry. She had spent hours squatting to empty cupboards for a house move in Australia. By evening, her feet were numb and she found it hard to walk. Doctors believe the woman developed a condition called compartment syndrome, made worse by her skinny jeans. Compartment syndrome is a painful and potentially serious condition caused by bleeding or swelling within an enclosed bundle of muscles - in this case, the calves. The condition caused the woman to trip and fall and, unable to get up, she then spent several hours lying on the ground. On examination at the Royal Adelaide Hospital, her lower legs were severely swollen. Although her feet were warm and had enough blood supplying them, her muscles were weak and she had lost some feeling. As the pressure had built in her lower legs, her muscles and nerves became damaged. She was put on an intravenous drip and after four days was able to walk unaided. Other medics have reported a number of cases where patients have developed tingly, numb thighs from wearing the figure-hugging low-cut denim trousers - although the chance of it happening is still slim for most people. Priya Dasoju, professional adviser at the Chartered Society of Physiotherapy, said: "As with many of these warnings, the very unfortunate case highlighted is an extreme one. © 2015 BBC
Keyword: Movement Disorders
Link ID: 21084 - Posted: 06.23.2015
By Amanda Montañez As someone who works at the intersection of art and science, I have always found it easy to make the case that all artists are scientists. From the moment we pick up a crayon and make our first mark, we are experimenting. The perceived successes and failures of our craft are indelibly tied to the many variables—physical, chemical and psychological—inherent in the experiences of creating and consuming works of art. Yet, it seems a longer stretch, somehow, to argue that all scientists are artists. At the very least, in my experience, scientists seem less willing to claim this alternate title. In fact, almost anyone who does not see her or himself as artistically inclined tends to be a little too quick to proclaim, “Oh, I’m not an artist. I can’t even draw a straight line!” With a sigh, I’ll avoid the temptation to digress into the utter irrelevance of straight lines and one’s ability to draw them. Instead, I’d like to posit the idea that, while we may not all identify as artists, scientists, of all people, really should be artists. Throughout history, much of scientific discovery and advancement has hinged not just on our ability to see certain things, but also on our capacity to reproduce what we see in faithful, critical and/or meaningful ways. The drawings of the famous Spanish neuroscientist Santiago Ramón y Cajal provide an ideal example of this phenomenon. In the late 1800s, using a novel histological staining technique developed by Italian physician Camillo Golgi, Ramón y Cajal spent countless hours examining brain tissues under the microscope and recording what he saw in pen and ink.
Keyword: Brain imaging
Link ID: 21083 - Posted: 06.23.2015
By THE ASSOCIATED PRESS NEW HAVEN, Connecticut — To the untrained eye, it looked like a seismograph recording of a violent earthquake or the gyrations of a very volatile day on Wall Street — jagged peaks and valleys in red, blue and green, displayed on a wall. But the story it told was not about geology or economics. It was a glimpse into the brains of Shaul Yahil and Shaw Bronner, two researchers at a Yale lab, as they had a little chat. "This is a fork," Yahil observed, describing the image on his computer. "A fork is something you use to stab food while you're eating it. Common piece of cutlery in the West." "It doesn't look like a real fancy sterling silver fork, but very useful," Bronner responded. And then she described her own screen: "This looks like a baby chimpanzee ..." The jagged, multicolored images depicted what was going on in the two researchers' heads — two brains in conversation, carrying out an intricate dance of internal activity. This is no parlor trick. The brain-tracking technology at work is just a small part of the quest to answer abiding questions about the workings of a three-pound chunk of fatty tissue with the consistency of cold porridge. How does this collection of nearly 100 billion densely packed nerve cells, acting through circuits with maybe 100 trillion connections, let us think, feel, act and perceive our world? How does this complex machine go wrong and make people depressed, or delusional, or demented? What can be done about that? These are the kinds of questions that spurred President Barack Obama to launch the BRAIN initiative in 2013. Its aim: to spur development of new tools to investigate the brain. Europe and Japan are also pursuing major efforts in brain research. © 2015 The New York Times Company
Keyword: Brain imaging
Link ID: 21081 - Posted: 06.22.2015
Patricia Neighmond We all know that listening to music can soothe emotional pain, but Taylor Swift, Jay-Z and Alicia Keys can also ease physical pain, according to a study of children and teenagers who had major surgery. The analgesic effects of music are well known, but most of the studies have been done with adults and most of the music has been classical. Now a recent study finds that children who choose their own music or audiobook to listen to after major surgery experience less pain. The catalyst for the research was a very personal experience. Sunitha Suresh was a college student when her grandmother had major surgery and was put in intensive care with three other patients. This meant her family couldn't always be with her. So they decided to put her favorite south Indian classical Carnatic music on an iPod, so she could listen around the clock. It was very calming, Sunitha says. "She knew that someone who loved her had left that music for her and she was in a familiar place." This may be the most efficient way to get in shape, but it may also be the least fun. Suresh could see the music relaxed her grandmother and made her feel less anxious, but she wondered if she also felt less pain. That would make sense, because anxiety can make people more vulnerable to pain. At the time Suresh was majoring in biomedical engineering with a minor in music cognition at Northwestern University where her father, Santhanam Suresh, is a professor of anesthesiology and pediatrics. © 2015 NPR
Keyword: Pain & Touch
Link ID: 21080 - Posted: 06.22.2015
By Mitch Leslie After years of fasting, the Buddha’s “legs were like bamboo sticks, his backbone was like a rope, his chest was like an incomplete roof of a house, his eyes sank right inside, like stones in a deep well,” according to one account. The Buddha didn’t get what he wanted from this extreme fasting—enlightenment—but a new study suggests that a diet that replicates some effects of milder deprivation may not only lower your weight but also confer other benefits. Researchers report that following the diet for just 5 days a month improves several measures of health, including reducing the risk of developing cardiovascular disease. Eating shortens life, and not just because overindulgence can lead to diseases such as diabetes. A diet that cuts food intake by up to 40%, known as calorie restriction, increases longevity in a variety of organisms and forestalls cancer, heart disease, and other late-life illnesses. Although some short-term studies suggest that calorie restriction provides metabolic benefits to people, nobody has confirmed that it also increases human life span. The closest researchers have come are two large, long-term studies of monkeys, and they conflict about whether meager rations increase longevity. Even if calorie restriction could add years to our lives, almost no one can muster the willpower to eat so little day after day, year after year. An alternative that might be more, er, palatable is fasting, the temporary abstinence from food. Gerontological researcher Valter Longo of the University of Southern California in Los Angeles and colleagues have shown that fasting eases side effects of chemotherapy such as fatigue and weakness, and animal studies suggest that it produces health advantages similar to calorie restriction. © 2015 American Association for the Advancement of Science.
Link ID: 21077 - Posted: 06.20.2015
By Tina Rosenberg Elle is a mess. She’s actually talented, attractive and good at her job, but she feels like a fraud — convinced that today’s the day she’ll flunk a test, lose a job, mess up a relationship. Her colleague Moody also sabotages himself. He’s a hardworking, nice person, but loses friends because he’s grumpy, oversensitive and gets angry for no reason. If you suffer from depression or anxiety as Elle and Moody do, spending time with them could help. They are characters in a free online program of cognitive behavioral therapy called MoodGYM, which leads users through quizzes and exercises — therapy without the therapist. Cognitive behavioral therapy is a commonly used treatment for depression, anxiety and other conditions. With it, the therapist doesn’t ask you about your mother — or look at the past at all. Instead, a cognitive behavioral therapist aims to give patients the skills to manage their moods by helping them identify unhelpful thoughts like “I’m worthless,” “I’ll always fail” or “people will always let me down.” Patients learn to analyze them and replace them with constructive thoughts that are more accurate or precise. For example, a patient could replace “I fail at everything” with “I succeed at things when I’m motivated and I try hard.” That new thought in turn changes feelings and behaviors. The success of cognitive behavioral therapy is well known; many people consider it the most effective therapy for depression. What is not widely known, at least in the United States, is that you don’t need a therapist to do it. Scores of studies have found that online C.B.T. works as well as conventional face-to-face cognitive behavioral therapy – as long a there is occasional human support or coaching. “For common mental disorders like anxiety and depression, there is no evidence Internet-based treatment is less effective than face-to-face therapy,” said Pim Cuijpers, professor of clinical psychology at the Vrije Universiteit Amsterdam and a leading researcher on computer C.B.T. © 2015 The New York Times Company
Link ID: 21076 - Posted: 06.20.2015
by Sarah Zielinski Last year in Australia, I visited Featherdale Wildlife Park where, in a couple of areas, kangaroos and wallabies hop amongst the tourists. For a dollar, you can buy an ice cream cone full of grass for the marsupials to eat. But if you’re not careful, an animal will quickly grab the cone out of your hand and feed itself. Now I’m wishing that I had paid more attention to that grabbing motion. Kangaroos are lefties, scientists report June 18 in Current Biology. And the preference for one hand over the other may be linked to the ability to walk on two legs. Humans show a definite preference for one hand over the other, usually the right. This handedness had been considered a distinctly human trait. But scientists have found more and more evidence that other species have such preferences as well. Female domestic cats, for instance, tend to use their right paws and males their left. Andrey Giljov of Saint Petersburg State University in Russia and colleagues were curious about the evolution of handedness and looked to marsupials, since these animals are an early offshoot of the mammal lineage. They observed four species in the wild — red kangaroos, eastern gray kangaroos, red-necked wallabies and Goodfellow’s tree kangaroos — performing tasks such as grooming and feeding. © Society for Science & the Public 2000 - 2015.
Link ID: 21075 - Posted: 06.20.2015
by Bob Holmes Lions might be one of the biggest threats to hyenas, but that doesn't stop the smaller animals teaming up to steal from the big cats. Nora Lewin from Michigan State University in East Lansing and her colleagues observed the mobbing behaviour at the Masai Mara National Reserve in Kenya. Hyenas were also spotted banding together to keep lions away from their dens. The mobbing involves a surprising degree of cooperation and communication. Male lions, which actively pursue and kill hyenas, are much more of a danger than females, who usually just make threats. This could be why the hyenas in the video above are confronting females. The team suggests the hyenas can identify their opponent's age and sex before deciding as a group whether or not to mob it. Levin and her colleagues are now investigating how the hyenas communicate to make a group decision. The findings were reported on 13 June at the annual meeting of the Animal Behavior Society in Anchorage, Alaska. © Copyright Reed Business Information Ltd.
Bill Chappell In what researchers say is a first, they've discovered the neuron in worms that detects Earth's magnetic field. Animals have been known to sense the magnetic field; a new study identifies the microscopic, antenna-shaped sensor that helps worms orient themselves underground. The sensory neuron that the worm C. elegans uses to migrate up or down through the soil could be similar to what many other animals use, according to the team of scientists and engineers at The University of Texas at Austin. The team's work was published Wednesday by eLife. In contrast to previous breakthroughs — such as a 2012 study on how pigeons' brains use information about magnetic fields, and another from the same year on olfactory cells in trout — the new work identifies the sensory neuron that detects magnetic fields. "We also found the first hint at a novel sensory mechanism for detecting the magnetic field," says Jon Pierce-Shimomura, an assistant professor of neuroscience who worked on the study. "Now researchers can check to see if this is used in other animals too." The list of animals that could be studied for their use of magnetic fields is long — and it seems to grow each year. In early 2014, for instance, a study found that dogs who need to relieve themselves of waste prefer to align themselves on a north-south axis when the magnetic conditions are right. Pierce-Shimomura says his team was surprised to make a new breakthrough in magnetism by looking at worms, which aren't known for their sophisticated migrations. © 2015 NPR
Keyword: Pain & Touch
Link ID: 21072 - Posted: 06.18.2015
by Curtis Abraham A step forward for equal LGBT rights in Africa. Last week, the influential Academy of Science of South Africa (ASSAf) published a study on the science of human sexual diversity. A comprehensive review of recent scientific papers on the subject, it concluded that sexual behaviour is naturally varied, and discrimination unjustified. It stated that there is no evidence that orientation can be altered by therapy or that being gay is contagious. The report also sets straight the idea that homosexuality is a Western malaise: "There is no basis for the view that homosexuality is 'un-African' either in the sense of it being a 'colonial import', or on the basis that prevalence of people with same-sex or bisexual orientations is any different in African countries compared to countries on any other continent." Going further, the report asserted not only that tolerance of sexual diversity benefits communities but it positively affects public health, civil society and long-term economic growth. Zero tolerance Launched at the Seventh South African AIDS Conference in Durban, the study comes a year after the Ugandan government passed a law imposing a life sentence on anyone who has sexual relations with someone of the same sex. Other countries, including Burundi, Cameroon and Nigeria, then passed similar anti-gay laws. © Copyright Reed Business Information Ltd.
Keyword: Sexual Behavior
Link ID: 21071 - Posted: 06.18.2015
By Greg Toppo On the morning of August 12, 2013, nearly eight months after 20-year-old Adam Lanza shot his way into Sandy Hook Elementary School in Newtown, Conn., and killed 26 people, Michael Mudry, an investigator with the Connecticut State Police, drove to nearby Danbury to try to solve a little mystery. Police had found a Garmin GPS unit in Lanza's house, and its records showed that the gunman had driven to the same spot nine times in April, May and June 2012, arriving around midnight each time and staying for hours. The GPS readout took Mudry to the vast parking lot of a suburban shopping center, about 14 miles west of Lanza's home. Workers at a movie theater there immediately recognized Lanza from a photograph. He was at the theater constantly, they told Mudry, but never to see movies. He came to the lobby to play an arcade game, the same one, over and over again, sometimes for eight to 10 hours a night. Witnesses said he would whip himself into a frenzy, and on occasion the theater manager had to unplug the game to get him to leave. Police had been scouring Lanza's home since the shootings, and on his computer hard drive they found information on weapons magazine capacities, images of Columbine killers Eric Harris and Dylan Klebold, copies of the violent movies Bloody Wednesday and Rampage, and a list of ingredients for TNT. And like many teenaged boys, Lanza owned the typical first-person shooter, fighting and action games: Call of Duty, Dead or Alive, Grand Theft Auto. © 2015 Scientific American,
Link ID: 21068 - Posted: 06.18.2015
By Andrea Alfano There are many types of touch. A cold splash of water, the tug of a strong breeze or the heat and heft of your coffee mug will each play on your skin in a different way. Within your skin is an array of touch sensors, each associated with nerve fibers that connect to the central nervous system. These sensors comprise specialized nerve endings and skin cells. Along with the fibers, they translate our physical interactions with the world into electrical signals that our brain can process. They help to bridge the gap between the physical act of touching and the cognitive awareness of tactile sensation. Even a simple stroke across the forearm engages several distinct nerve fibers. Three types—A-beta, A-delta and C fibers—have subtypes that are specialized for sensing particular types of touch; other subtypes carry information related to pain. The integration of information from these fibers is what allows us to gain such rich sensory experiences through our skin, but it has also made it more challenging for researchers to understand the fibers’ individual roles. Although these fibers do not act in isolation, the examples that follow highlight the primary nerve fibers engaged by different types of touch. © 2015 Scientific American
Keyword: Pain & Touch
Link ID: 21066 - Posted: 06.18.2015
The structure of the living cell is defined by the difference between what’s inside and what’s not. Biologists have taken great pains over the years to document the minute workings of the openings in cell membranes that allow hydrogen, sodium, calcium and other ions to make their way inside across the barrier that envelops the cell and its contents. Five scholars of the brain have built upon these observations to suggest that these activities may provide a foundation for a badly needed theory to understand consciousness and some of the cognitive processes that underlie it. They contend that when animal cells open and close themselves to the outside world, these actions can be construed as more than just responses to external stimuli. In fact, they constitute the basis for perception, cognition and movement in the animal kingdom—and may underlie consciousness itself. Read about what the five have to say and then continue to Koch’s reply. The five authors and NYU neurology professor Oliver Sacks; Antonio Damasio and Gil B. Carvalho from the University of Southern California, Norman D. Cook from the faculty of Kansai University in Osaka, Japan and Harry T. Hunt from Brock University in Ontario. They have framed their ideas in the form of an open letter to Christof Koch, president of the Allen Institute for Brain Science, and a Scientific American MIND columnist (Consciousness Redux) and member of Scientific American’s board of advisers.
Link ID: 21065 - Posted: 06.17.2015
By James Gallagher Health editor, BBC News website Scientists have discovered a chemical in blood that indicates whether people will have declining brain function. Looking for the earliest signs of Alzheimer's disease, they analysed levels of 1,129 proteins circulating in the blood of more than 200 twins. These were compared with data from cognitive-function tests over the next decade, in Translational Psychiatry. And levels of one protein, MAPKAPK5, tended to be lower in those people whose brains declined. MAPKAPK5 is involved in relaying chemical messages within the body, although its connection with cognitive decline is unclear. Dementia cases are expected to treble globally by 2050, but there is no cure or treatment. It can take more than a decade from the first changes in the brain to culminate in symptoms such as memory loss, confusion and personality change. And drug companies believe they need to treat patients years before symptoms appear in order to protect the brain. Dr Steven Kiddle, a Medical Research Council scientist at King's College London, told the BBC News website: "People think it may be hard to reverse 20 years of potential damage to your brain. "But if you could start much earlier in that process, then you might be able to find something that works." He said a blood test could help identify people for clinical trials. But he added: "A test you could go in to your doctor to say, 'Do I have Alzheimer's disease or not?' I think that's a long way off." © 2015 BBC
Link ID: 21064 - Posted: 06.17.2015
By Tori Rodriguez Joint flexibility is an oft-coveted trait that provides a special advantage to dancers and athletes, but there can be too much of this good thing. A growing body of research suggests a surprising link between high levels of flexibility and anxiety. A study published last year in the journal Frontiers in Psychology is among the most recent to confirm the association, finding that people with hypermobile joints have heightened brain activity in anxiety regions. Joint hypermobility, which affects approximately 20 percent of the population, confers an unusually large range of motion. Hypermobile people can often, for instance, touch their thumb to their inner forearm or place their hands flat on the floor without bending their knees. The trait appears to be genetic and is a result of variation in collagen, the main structural protein of connective tissue. Being double-jointed has long been linked with an increased risk for asthma and irritable bowel syndrome, among other physical disorders. “Joint hypermobility has an impact on the whole body and not just joints,” says Jessica Eccles, a psychiatrist and researcher at the University of Sussex in England. It was only a matter of time before scientists also looked at whether joint hypermobility was linked to mental disorders. The investigation began in 1993 and heated up in 1998 when researcher Rocío Martín-Santos, now at the Hospital Clinic of the University of Barcelona, and her colleagues discovered that patients with anxiety were 16 times more likely to have lax joints. Their findings have since been replicated numerous times in large populations. © 2015 Scientific American