Chapter 19. Language and Hemispheric Asymmetry
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By David Shultz Mice supposedly don't speak, so they can't stutter. But by tinkering with a gene that appears to be involved in human speech, researchers have created transgenic mice whose pups produce altered vocalizations in a way that is similar to stuttering in humans. The mice could make a good model for understanding stuttering; they could also shed more light on how mutations in the gene, called Gnptab, cause the speech disorder. Stuttering is one of the most common speech disorders in the world, affecting nearly one out of 100 adults in the United States. But the cause of the stammering, fragmented speech patterns remains unclear. Several years ago, researchers discovered that stutterers often have mutations in a gene called Gnptab. Like a dispatcher directing garbage trucks, Gnptab encodes a protein that helps to direct enzymes into the lysosome—a compartment in animal cells that breaks down waste and recycles old cellular machinery. Mutations to other genes in this system are known to lead to the buildup of cellular waste products and often result in debilitating diseases, such as Tay-Sachs. How mutations in Gnptab causes stuttered speech remains a mystery, however. To get to the bottom of things, neuroscientist Terra Barnes and her team at Washington University in St. Louis in Missouri produced mice with mutation in the Gnptab gene and studied whether it affected the ultrasonic vocalizations that newly born mouse pups emit when separated from their mothers. Determining whether a mouse is stuttering is no easy task; as Barnes points out, it can even be difficult to tell whether people are stuttering if they’re speaking a foreign language. So the team designed a computer program that listens for stuttering vocalization patterns independent of language. © 2016 American Association for the Advancement of Science.
Link ID: 22110 - Posted: 04.16.2016
By Robin Wylie Bottlenose dolphins have been observed chattering while cooperating to solve a tricky puzzle – a feat that suggests they have a type of vocalisation dedicated to cooperating on problem solving. Holli Eskelinen of Dolphins Plus research institute in Florida and her colleagues at the University of Southern Mississippi presented a group of six captive dolphins with a locked canister filled with food. The canister could only be opened by simultaneously pulling on a rope at either end. The team conducted 24 canister trials, during which all six dolphins were present. Only two of the dolphins ever managed to crack the puzzle and get to the food. The successful pair was prolific, though: in 20 of the trials, the same two adult males worked together to open the food canister in a matter of few minutes. In the other four trials, one of the dolphins managed to solve the problem on its own, but this was much trickier and took longer to execute. But the real surprise came from recordings of the vocalisations the dolphins made during the experiment. The team found that when the dolphins worked together to open the canister, they made around three times more vocalisations than they did while opening the canister on their own or when there was either no canister present or no interaction with the canister in the pool. © Copyright Reed Business Information Ltd.
By Frank McGurty More than 40 percent of retired NFL players tested with advanced scanning technology showed signs of traumatic brain injury, a much higher rate than in the general population, according to a new study of the long-term risks of playing American football. The research, presented at an American Academy of Neurology meeting that began in Vancouver on Monday, is one of the first to provide "objective evidence" of traumatic brain injury in a large sample of National Football League veterans while they are living, said Dr. Francis X. Conidi, one of the study's authors. Conidi, a neurologist at the Florida Center for Headache and Sports Neurology and a faculty member at the Florida State University College of Medicine, said traumatic brain injury was often a "precursor" to CTE, a degenerative brain disease. "What we do know is that players with traumatic brain injury have a high incidence of going on to develop neurological degenerative disease later on in life," Conidi told Reuters. CTE, or chronic traumatic encephalopathy, has been found in dozens of the NFL's top players after they died. At present, a CTE diagnosis is only possible after death. The brain tissue of 59 or 62 deceased former NFL players examined by Boston University's CTE Center have tested positive for CTE, according to its website. The disease, which can lead to aggression and dementia, may have led to the suicides of several NFL athletes, including Hall of Famer Junior Seau. In the new study, the largest of its kind, 40 living former players were given sensitive brain scans, known as diffusion tensor imaging (DTI), as well as thinking and memory tests. © 2016 Scientific American,
By Catherine Matacic How does sign language develop? A new study shows that it takes less than five generations for people to go from simple, unconventional pantomimes—essentially telling a story with your hands—to stable signs. Researchers asked a group of volunteers to invent their own signs for a set of 24 words in four separate categories: people, locations, objects, and actions. Examples included “photographer,” “darkroom,” and “camera.” After an initial group made up the signs—pretending to shoot a picture with an old-fashioned camera for “photographer,” for example—they taught the signs to a new generation of learners. That generation then played a game where they tried to guess what sign another player in their group was making. When they got the answer right, they taught that sign to a new generation of volunteers. After a few generations, the volunteers stopped acting out the words with inconsistent gestures and started making them in ways that were more systematic and efficient. What’s more, they added markers for the four categories—pointing to themselves if the category were “person” or making the outline of a house if the category were “location,” for example—and they stopped repeating gestures, the researchers reported last month at the Evolution of Language conference in New Orleans, Louisiana. So in the video above, the first version of “photographer” is unpredictable and long, compared with the final version, which uses the person marker and takes just half the time. The researchers say their finding supports the work of researchers in the field, who have found similar patterns of development in newly emerging sign languages. The results also suggest that learning and social interaction are crucial to this development. © 2016 American Association for the Advancement of Science
Link ID: 22084 - Posted: 04.09.2016
Laura Sanders NEW YORK — Lip-readers’ minds seem to “hear” the words their eyes see being formed. And the better a person is at lipreading, the more neural activity there is in the brain’s auditory cortex, scientists reported April 4 at the annual meeting of the Cognitive Neuroscience Society. Earlier studies have found that auditory brain areas are active during lipreading. But most of those studies focused on small bits of language — simple sentences or even single words, said study coauthor Satu Saalasti of Aalto University in Finland. In contrast, Saalasti and colleagues studied lipreading in more natural situations. Twenty-nine people read the silent lips of a person who spoke Finnish for eight minutes in a video. “We can all lip-read to some extent,” Saalasti said, and the participants, who had no lipreading experience, varied widely in their comprehension of the eight-minute story. In the best lip-readers, activity in the auditory cortex was quite similar to that evoked when the story was read aloud, brain scans revealed. The results suggest that lipreading success depends on a person’s ability to “hear” the words formed by moving lips, Saalasti said. Citations J. Alho et al. Similar brain responses to lip-read, read and listened narratives. Cognitive Neuroscience Society annual meeting, New York City, April 4, 2016. Further Reading © Society for Science & the Public 2000 - 2016.
Link ID: 22077 - Posted: 04.07.2016
Laura Sanders NEW YORK — Cells in a brain structure known as the hippocampus are known to be cartographers, drawing mental maps of physical space. But new studies show that this seahorse-shaped hook of neural tissue can also keep track of social space, auditory space and even time, deftly mapping these various types of information into their proper places. Neuroscientist Rita Tavares described details of one of these new maps April 2 at the annual meeting of the Cognitive Neuroscience Society. Brain scans had previously revealed that activity in the hippocampus was linked to movement through social space. In an experiment reported last year in Neuron, people went on a virtual quest to find a house and job by interacting with a cast of characters. Through these social interactions, the participants formed opinions about how much power each character held, and how kindly they felt toward him or her. These judgments put each character in a position on a “social space” map. Activity in the hippocampus was related to this social mapmaking, Tavares and colleagues found. It turns out that this social map depends on the traits of the person who is drawing it, says Tavares, of Icahn School of Medicine at Mount Sinai in New York City. People with more social anxiety tended to give more power to characters they interacted with. What’s more, these people's social space maps were smaller overall, suggesting that they explored social space less, Tavares says. Tying these behavioral traits to the hippocampus may lead to a greater understanding of social behavior — and how this social mapping may go awry in psychiatric conditions, Tavares said. © Society for Science & the Public 2000 - 2016.
Keyword: Learning & Memory
Link ID: 22076 - Posted: 04.06.2016
By BENEDICT CAREY Some scientists studying the relationship between contact sports and memory or mood problems later in life argue that cumulative exposure to hits that cause a snap of the head — not an athlete’s number of concussions — is the most important risk factor. That possibility is particularly worrisome in football, in which frequent “subconcussive” blows are unavoidable. On Thursday, researchers based at Boston University reported the most rigorous evidence to date that overall exposure to contact in former high school and college football players could predict their likelihood of experiencing problems like depression, apathy or memory loss years later. The finding, appearing in The Journal of Neurotrauma, is not conclusive, the authors wrote. Such mental problems can stem from a variety of factors in any long life. Yet the paper represents researchers’ first attempt to precisely calculate cumulative lifetime exposure to contact in living players, experts said. Previous estimates had relied in part on former players’ memories of concussions, or number of years played. The new paper uses more objective measures, including data from helmet accelerometer studies, and provides a glimpse of where the debate over the risk of contact sports may next play out, the experts said. “They used a much more refined and quantitative approach to estimate exposure than I’ve seen in this area,” said John Meeker, a professor of environmental health sciences at the University of Michigan School of Public Health, who was not a part of the research team. But he added, “Their methods will have to be validated in much larger studies; this is very much a preliminary finding.” The study did not address the risk of chronic traumatic encephalopathy, or C.T.E., a degenerative scarring in the brain tied to head blows, which can be diagnosed only after death. © 2016 The New York Times Company
Keyword: Brain Injury/Concussion
Link ID: 22060 - Posted: 04.01.2016
By Elizabeth Pennisi The “brrreeet” you hear in the video above is not coming from this broadbill’s beak, but rather from its wings. Charles Darwin marveled at “instrumental music” of birds—from the rattled quills of peacocks to the wing-drumming of grouse and the wing “booming” of night-jars. But those percussive noises are no match for the definitive tones generated by the three Smithornis broadbills (S. rufolateralis, S. capensis, and S. sharpei) that live in remote forests in sub-Saharan Africa. One bird acoustics specialist was so intrigued in 1986 by a recording of this “song,” that he vowed to hear it for himself. More than 2 years ago, he and his colleagues tracked two of these species down in the wild. Synchronized high-speed video and acoustic recordings revealed the downstroke of the wings produces the tones as the bird flies in a meter-wide oval from its perch and back again. At first the researchers thought the outermost flight feathers flutter to make the sounds, but studies of a wing and of the feathers themselves in a wind tunnel showed that the inner flight feathers are “singing” the most, the team reports today in the Journal of Experimental Biology. The tones may scale with the species’ body and feather size, with the bigger ones producing deeper tones, the researchers suggest. The wing tones seemed to have replaced vocal singing, they note, and are likely unique to this group of birds. Audible 100 meters away in dense forest, they represent yet another innovation for communicating with one’s peers. © 2016 American Association for the Advancement of Science
By Jordana Cepelewicz The bacteria that inhabit our guts have become key players for neuroscientists. A growing body of research links them to a wide array of mental and neurological disorders—from anxiety and depression to schizophrenia and Alzheimer’s disease. Now a study in mice published this week in Nature Medicine suggests that striking the right microbial balance could cause changes in the immune system that significantly reduce brain damage after a stroke—the second leading cause of both death and disability for people around the globe. (Scientific American is part of Springer Nature.) Experts have known for some time that stroke severity is influenced by the presence of two types of cell, found abundantly within the intestine, that calibrate immune responses: Regulatory T cells have a beneficial inflammatory effect, protecting an individual from stroke. But gamma delta T cells produce a cytokine that causes harmful inflammation after a stroke. A team of researchers at Weill Cornell Medical College and Memorial Sloan Kettering Cancer Center set about investigating whether they could tilt the balance of these cells in the favor of beneficial cells by tinkering with the body’s bacterial residents. To do so, they bred two colonies of mice: One group’s intestinal flora was resistant to antibiotics whereas the other’s gut bacteria was vulnerable to treatment. As a result, when given a combination of antibiotics over the course of two weeks, only the latter’s microbiota underwent change. The researchers then obstructed the cerebral arteries of the mice, inducing an ischemic stroke (the most common type). They found that subsequent brain damage was 60 percent smaller in the drug-susceptible mice than it was in the other group. © 2016 Scientific American,
Link ID: 22054 - Posted: 03.31.2016
By Ariana Eunjung Cha In the movie "Concussion," which is based on the life of Bennet Omalu, a doctor who studied traumatic brain injury, Omalu explains that the reason the prognosis is so poor for so many of them is because their symptoms went undiagnosed. When head injuries aren't treated or are under-treated, it puts patients at risk of more serious injury. This is why children with concussions are often asked not to return to class or sports until their symptoms have resolved and adults often have to take days off work. One of the challenges has been that concussions are tricky to diagnose, and it isn't uncommon for a patient to rush to the ER only to be met with a vague response from the doctor about whether there's anything worrisome. Symptoms often aren't apparent for hours or even days after the initial injury, and the imaging technology we have can't pick up anything other than larger bleeds and lesions. How different could things have been if there was a simple blood test to detect a concussion? In a paper published in JAMA Neurology on Monday, researchers reported that they may be closer than ever to such a test. The study involved 600 patients admitted to a trauma center from March 2010 to March 2014. All had suffered some kind of head injury resulting in loss of consciousness, amnesia or disorientation.
By BENEDICT CAREY BEDFORD, Mass. — In a small room banked by refrigerators of preserved brains, a pathologist held a specimen up to the light in frank admiration. Then it was time to cut — once in half and then a thick slice from the back, the tissue dense and gray-pink, teeming with folds and swirls. It was the brain of a professional running back. “There,” said Dr. Ann McKee, the chief of neuropathology at the V.A. Boston Healthcare System and a professor of neurology and pathology at Boston University’s medical school, pointing to a key area that had an abnormal separation. “That’s one thing we look for right away.” Over the past several years, Dr. McKee’s lab, housed in a pair of two-story brick buildings in suburban Boston, has repeatedly made headlines by revealing that deceased athletes, including at least 90 former N.F.L. players, were found to have had a degenerative brain disease called chronic traumatic encephalopathy, or C.T.E., that is believed to cause debilitating memory and mood problems. This month, after years of denying or playing down a connection, a top N.F.L. official acknowledged at a hearing in Washington that playing football and having C.T.E. were “certainly” linked. His statement effectively ended a very public dispute over whether head blows sustained while playing football are associated with the disorder. But it will not resolve a quieter debate among scientists about how much risk each football player has of developing it, or answer questions about why some players seem far more vulnerable to it than others. Some researchers worry that the rising drumbeat of C.T.E. diagnoses is far outpacing scientific progress in pinpointing the symptoms, risks and prevalence of the disease. The American Academy of Clinical Neuropsychology, an organization of brain injury specialists, is preparing a public statement to point out that much of the science of C.T.E. is still unsettled and to contend that the evidence to date should not be interpreted to mean that parents must keep their children off sports teams, officials of the group say. © 2016 The New York Times Company
By DAVID FRANK and JAMES GORMAN Social life is good for you, even when your friends have lice — if you’re a Japanese macaque. Whether the same is true for humans hasn’t been tested directly, at least not the way researchers in Japan conducted their experiments with networks of female macaques. Julie Duboscq, a researcher at Kyoto University’s Primate Research Institute in Japan, tracked louse infestation and grooming interactions in about 20 adult female macaques. As she, Andrew J.J. MacIntosh and their colleagues noted in describing their research in Scientific Reports, grooming is known to reduce lice, but such close physical contact can also make it easy for lice to pass from one animal to another. Dr. Duboscq is interested in the costs and benefits of social behavior. For animals that live in social groups, as macaques and people do, the benefits of social life are many, from defense against predators (for wild monkeys, and no doubt for humans at some point in their history) to emotional health and well-being (for humans, and probably monkeys, too). But there are negatives associated with sociality, like the transmission of parasites and diseases. “We don’t fully understand the costs and benefits,” Dr. Duboscq said. In this study, she and her colleagues estimated the degree of louse infestation by the number of nits picked. The more nits, they calculated, the more lice-producing nits. © 2016 The New York Times Company
Link ID: 22038 - Posted: 03.28.2016
By ALAN SCHWARZ, WALT BOGDANICH and JACQUELINE WILLIAMS With several of its marquee players retiring early after a cascade of frightening concussions, the league formed a committee in 1994 that would ultimately issue a succession of research papers playing down the danger of head injuries. Amid criticism of the committee’s work, physicians brought in later to continue the research said the papers had relied on faulty analysis. Now, an investigation by The New York Times has found that the N.F.L.’s concussion research was far more flawed than previously known. For the last 13 years, the N.F.L. has stood by the research, which, the papers stated, was based on a full accounting of all concussions diagnosed by team physicians from 1996 through 2001. But confidential data obtained by The Times shows that more than 100 diagnosed concussions were omitted from the studies — including some severe injuries to stars like quarterbacks Steve Young and Troy Aikman. The committee then calculated the rates of concussions using the incomplete data, making them appear less frequent than they actually were. After The Times asked the league about the missing diagnosed cases — more than 10 percent of the total — officials acknowledged that “the clubs were not required to submit their data and not every club did.” That should have been made clearer, the league said in a statement, adding that the missing cases were not part of an attempt “to alter or suppress the rate of concussions.” One member of the concussion committee, Dr. Joseph Waeckerle, said he was unaware of the omissions. But he added: “If somebody made a human error or somebody assumed the data was absolutely correct and didn’t question it, well, we screwed up. If we found it wasn’t accurate and still used it, that’s not a screw-up; that’s a lie.” These discoveries raise new questions about the validity of the committee’s findings, published in 13 peer-reviewed articles and held up by the league as scientific evidence that brain injuries did not cause long-term harm to its players. It is also unclear why the omissions went unchallenged by league officials, by the epidemiologist whose job it was to ensure accurate data collection and by the editor of the medical journal that published the studies. © 2016 The New York Times Company
Keyword: Brain Injury/Concussion
Link ID: 22035 - Posted: 03.26.2016
By Catherine Matacic Twenty-three years ago, a bonobo named Kanzi (above) aced a test in understanding human language. But a new study reveals he may not be as brainy as scientists thought—at least when it comes to grammar. The original test consisted of 660 verbal commands, in English, that asked Kanzi to do things like "show me the hot water" and "pour cold water in the potty." Overall, the ape did well, responding correctly 71.5% of the time (compared with 66.6% for an infant human). But when the researchers asked him to perform an action on more than one item, his performance plummeted to just 22.2%, according to the new analysis. When he was asked to "give the lighter and the shoe to Rose," for example, he gave Rose the lighter, but no shoe. When asked to "give the water and the doggie to Rose," he gave her the toy dog, but no water. The cause? Animals like bonobos may have a harder time than humans in processing complex noun phrases like “water and doggie,” linguist Robert Truswell of the University of Edinburgh reported in New Orleans, Louisiana, this week at the Evolution of Language conference. This feature of grammar—which effectively “nests” one unit within the bigger construct of a sentence—is easily picked up by humans, allowing us to communicate—and understand—more complex ideas. But Truswell cautions that humans probably aren’t born with the ability to interpret this kind of nesting structure. Instead, we must be taught how to use it. © 2016 American Association for the Advancement of Science
By Jordana Cepelewicz Last week a senior National Football League official acknowledged for the first time the link between head injuries in professional football and a degenerative brain disease called chronic traumatic encephalopathy. The admission—which has been compared with Big Tobacco’s 1997 disclosure that smoking causes cancer—comes at a time when the dangers of less severe traumatic brain injuries (TBIs), including concussions, have also been making headlines. Scientists do not yet understand the biological mechanisms underlying the detrimental effects of TBI—and as a result, effective treatments remain elusive. In fact, how to deal with even a mild concussion is the subject of debate: Some doctors prescribe rest for several weeks whereas others claim this may have negative consequences and urge patients to stay active. Now it turns out that the type of rest patients get may be key. In a study on rats published this week in The Journal of Neuroscience a team of researchers at University Hospital Zurich (UHZ) found that enhancing the slow-wave cycle of sleep after a traumatic head injury preserves brain function and minimizes damage to axons, the long projections from neurons that send signals to other cells in the brain. Previous research has shown that TBIs cause axonal damage as well as the buildup of neurotoxic molecular waste products that result from injury. In the new study the researchers examined two different methods of inducing a slow-wave sleep state—the deepest sleep stage characterized by low-frequency, high-amplitude waves. During this stage, the brain clears out protein buildup, leading the researchers to question whether it could help treat rats that had suffered a brain injury. © 2016 Scientific American
Nicola Davis Electrical brain stimulation could benefit stroke patients by boosting the effects of rehabilitation therapy, new research suggests. Writing in the journal Science Translational Medicine, the authors reveal that patients who were given electrical brain stimulation during a rehabilitation programme performed better on a range of tasks than those taking part in the rehabilitation programme. “It is an exciting message because there is so much frustration about people not reaching their true recovery potential,” said Professor Heidi Johansen-Berg, an author of the study from the University of Oxford, highlighting the fact that the cost of programmes and limited availability of therapists often restricts the amount of rehabilitation offered to patients. To probe the effects of brain stimulation, the researchers chose 24 patients who had experienced a stroke at least six months before, and who had difficulties with moving one hand. The participants were then split into two groups. The first group underwent nine consecutive days of rehabilitation training, with each session lasting an hour. For the first 20 minutes, the patients had two electrodes placed on their heads and a direct current applied, a process known as anodal transcranial direct current stimulation (tDCS). This is stimulation is thought to prime the brain for learning. © 2016 Guardian News and Media Limited
Link ID: 22000 - Posted: 03.17.2016
By KEN BELSON and ALAN SCHWARZ Perhaps no one will remember the setting, a hearing room for the House Energy and Commerce Committee, or the person who asked the question, a member of the House of Representatives from Illinois. But seven words spoken in the Rayburn House Office Building in Washington on Monday could profoundly affect the country’s most popular sport. After years of the N.F.L.‘s disputing evidence that connected football to chronic traumatic encephalopathy, the degenerative brain disease found in nearly 100 former players, a top official for the league for the first time acknowledged the link. To many, it was an echo of big tobacco’s confession in 1997 that smoking causes cancer and heart disease. Representative Jan Schakowsky, Democrat of Illinois, asked during a round-table discussion about concussions whether “there is a link between football and degenerative brain disorders like C.T.E.” Jeff Miller, the N.F.L.’s senior vice president for health and safety policy, said, “The answer to that is certainly, yes.” His response signaled a stunning about-face for the league, which has been accused by former players and independent experts of hiding the dangers of head injuries for decades. His reply came moments after a leading C.T.E. researcher — Dr. Ann McKee — had presented her findings, showing that dozens of former players who had died were afflicted with the disease. “The comments made by Jeff Miller yesterday accurately reflect the view of the N.F.L.,” Brian McCarthy, a league spokesman, said Tuesday, confirming that Mr. Miller had not misspoken. © 2016 The New York Times Company
Keyword: Brain Injury/Concussion
Link ID: 21997 - Posted: 03.16.2016
A senior British doctor, who has been an expert defence witness for parents accused of killing their children, has been found guilty of multiple charges that include giving misleading evidence in court. The Medical Practitioners Tribunal Service said that Waney Squier, a consultant pathologist at John Radcliffe Hospital in Oxford, UK, had failed to work within the limits of her competence, failed to be objective and unbiased, and failed to heed the views of other experts. In many of the cases investigated, her actions were deliberately misleading and irresponsible. The MPTS had considered Squier’s work as an expert witness in six child abuse cases and one appeal in which parents faced charges of non-accidental head injury, formerly known as shaken-baby syndrome. Squier is prominent among several researchers worldwide who have challenged a long-standing belief that a trio of symptoms of head injury provide unequivocal evidence of abusive behaviour. Squier has argued in the scientific literature and in court that the symptoms in question – haemorrhages on the surface of the brain, haemorrhages in the retinas, and a swollen brain – can have innocent causes, such as choking or other difficulties in breathing. These symptoms, they say, can also arise from the birthing process itself. Michele Codd, chair of the tribunal, gave examples of where the panel felt Squier’s court evidence had strayed outside her field of expertise. These included offering opinions on biomechanics in relation to injuries from falling, pathology of the eyes, and paediatric medicine. © Copyright Reed Business Information Ltd.
By Bob Roehr Retired American soccer star Brandi Chastain recently agreed to donate her brain to concussion research after her death. Females are often an unseen part of the concussion story even though they suffer more concussions than males, have more severe symptoms and are slower to recover. Just why is not completely clear, but the deficit in knowledge is slowly beginning to change thanks to women’s advocates behind Pink Concussions. The group gathered last weekend at Georgetown University to review the science behind concussions, and also to develop recommendations on gender-specific prevention protocols and clinical practices on how best to treat females with concussions. In comparable sports “female rates of concussions are much higher than those of their male counterparts,” says Zachary Kerr, director of the National Collegiate Athletic Association (NCAA) Injury Surveillance Program. Over a five-year period the rates per 1000 athlete-exposures were 6.3 in females versus 3.4 in males in soccer, 6.0 in females versus 3.9 in males in basketball and 3.3 in females versus 0.9 in males in baseball and softball. Only in swimming and diving did male rates (0.3) exceed those of females (0.5). Headache, dizziness and difficulty concentrating were roughly similar among both sexes, Kerr says. But among injured high school athletes, “larger portions of females are reporting sensitivity to light, sensitivity to noise, nausea and drowsiness,” he says. They were also slower to return to normal activity. The difference between the incidence and severity of concussions between the sexes does not start at birth, because infants and young children of both sexes have similar rates and symptoms with concussions. Puberty, however, which marks a significant developmental fork in the road for males and females, also marks a divergence for concussions. © 2016 Scientific American
By Nala Rogers Treatments that zap the brain with magnets or electricity are rising in popularity, and some evidence suggests they can help lift depression. But scientists are starting to wonder whether they could be hitting the wrong place in left-handed patients. Now, two small studies suggest this could very well be the case. “This is the kind of question that’s been desperately needed for many years,” says Jim Coan, a clinical psychologist at the University of Virginia in Charlottesville who was not involved in the project. “Most researchers in this area, including myself, have selected samples that are strongly right-handed, just in order to avoid mess in the data.” Past studies have suggested that the spots targeted by both kinds of stimulation—located in the left hemisphere—are likely to process “approach” emotions such as happiness, curiosity, and anger, which drive people to reach out and engage with the world. Some studies have also hinted that the brain’s right hemisphere is more involved in so-called “avoidance” emotions such as sorrow and fear. But the studies that support this separation of emotion into the two halves of the brain have relied almost exclusively on right-handed individuals. To figure out whether something else was happening with lefties, University of Chicago in Illinois neuroscientist Daniel Casasanto designed two studies: one to link personality to patterns of brain activity and another to measure the outcome of common brain stimulation treatments in right-handed and left-handed individuals. The brain stimulation treatments were originally designed to treat depression by boosting feelings of happiness and engagement, which motivate “approach” behaviors such as exploring the world and interacting with friends. © 2016 American Association for the Advancement of Science.