Chapter 19. Language and Hemispheric Asymmetry

Follow us on Facebook and Twitter, or subscribe to our mailing list, to receive news updates. Learn more.


Links 41 - 60 of 1873

The long-term impact of roadside bombings on the brains of Canadian soldiers in Afghanistan is the focus of two research projects underway in Western Canada. "In recent years, encounters with improvised explosive devices or IEDs in Afghanistan have inflicted traumatic brain injury on a number of Canadian soldiers," said Dr. Robert Thirsk, a former Canadian astronaut who is now a vice-president with the Canadian Institute of Health Research. "The impact of these blasts may not be immediately apparent. Months after the event the soldiers can suffer from the neurological problems and the mental disorders like anxiety that we're reading about in the newspapers. These weapons may be improvised, but our response to them needs to be strategic." Dr. Yu Tian Wang of the Brain Research Center at the University of British Columbia is looking at the biological changes that occur in the brain at the cellular level following an injury by an explosive device. Wang is studying whether a drug can reduce the death and dysfunction of brain cells following injury. "We know that during traumatic brain injuries some synaptic connections become weakened and the information from one neuron to another is slowed down," Wang said. "Now we know the underlying reason is due to a particular memory surface protein being reduced." Wang said an injection of peptides could provide protection to brain cells before a blast and possibly help repair damage if given immediately after an explosion. © CBC 2013

Keyword: Brain Injury/Concussion
Link ID: 18907 - Posted: 11.11.2013

by Catherine de Lange Speak more than one language? Bravo! It seems that being bilingual helps delay the onset of several forms of dementia. Previous studies of people with Alzheimer's disease in Canada showed that those who are fluent in two languages begin to exhibit symptoms four to five years later than people who are monolingual. Thomas Bak at the University of Edinburgh, UK, wanted to know whether this was truly down to language, or whether education or immigration status might be driving the delay, since most bilingual people living in Toronto, where the first studies were conducted, tended to come from an immigrant background. He also wondered whether people suffering from other forms of dementia might experience similar benefits. He teamed up with Suvarna Alladi, a neurologist working on memory disorders at Nizam's Institute of Medical Sciences (NIMSH) in Hyderabad, India. "In India, bilingualism is part of everyday life," says Bak. The team compared the age that dementia symptoms appeared in some 650 people who visited the NIMSH over six years. About half spoke at least two languages. This group's symptoms started on average four and a half years later than those in people who were monolingual. "Incredibly the number of years in delay of symptom onset they reported in the Indian sample is identical to our findings," says Ellen Bialystok, at Toronto's York University, who conducted the original Canadian studies. What's more, the same pattern appeared in three different types of dementia: Alzheimer's, frontotemporal and vascular. The results also held true for a group of people who were illiterate, suggesting that the benefits of being bilingual don't depend on education. © Copyright Reed Business Information Ltd.

Keyword: Alzheimers; Aggression
Link ID: 18886 - Posted: 11.07.2013

Elizabeth Pennisi Speak easy. The language gene FOXP2 may work through a protein partner that stimulates the formation of excitatory connections (green) in nerve cells (magenta). Few genes have made the headlines as much as FOXP2. The first gene associated with language disorders, it was later implicated in the evolution of human speech. Girls make more of the FOXP2 protein, which may help explain their precociousness in learning to talk. Now, neuroscientists have figured out how one of its molecular partners helps Foxp2 exert its effects. The findings may eventually lead to new therapies for inherited speech disorders, says Richard Huganir, the neurobiologist at Johns Hopkins University School of Medicine in Baltimore, Maryland, who led the work. Foxp2 controls the activity of a gene called Srpx2, he notes, which helps some of the brain's nerve cells beef up their connections to other nerve cells. By establishing what SRPX2 does, researchers can look for defective copies of it in people suffering from problems talking or learning to talk. Until 2001, scientists were not sure how genes influenced language. Then Simon Fisher, a neurogeneticist now at the Max Planck Institute for Psycholinguistics in Nijmegen, the Netherlands, and his colleagues fingered FOXP2 as the culprit in a family with several members who had trouble with pronunciation, putting words together, and understanding speech. These people cannot move their tongue and lips precisely enough to talk clearly, so even family members often can’t figure out what they are saying. It “opened a molecular window on the neural basis of speech and language,” Fisher says. © 2013 American Association for the Advancement of Science

Keyword: Language; Aggression
Link ID: 18865 - Posted: 11.02.2013

by Bethany Brookshire Most of us see a wagging dog’s tail and think it’s got to be a good sign. Wagging = welcome, right? Especially if it’s the kind of wag that’s knocking over small items. But it turns out that not all wags are equal, and some are a lot more welcoming than others. When I walked into my college biology course freshman year, we started out with a discussion of symmetry. Most animal are built with some symmetry, either radial or bilateral — radial like a starfish, bilateral like a human. Symmetry means things, like health or attractiveness. But it turns out that asymmetry can mean things too. And an asymmetrical behavior might mean some important things for dogs. Marcello Siniscalchi of the University of Bari Aldo Moro in Italy and colleagues decided to look at asymmetry in dog wags. They noticed that sometimes, dogs wag more to the right, usually when seeing their owner or something else happy. They wag more to the left when they see something like a dominant or unfamiliar dog. So the wag itself could represent the emotional state of the dog doing the wagging. But can the dogs seeing the wagging (the wagees) tell the difference? In a paper published October 31 in Current Biology, the authors found that they can. They used videos of a real dog or the silhouette of a dog wagging to the right (the wagging dog’s right, by the way) or to the left, and examined 43 other dogs as they watched (OK, they started with 56, but 13 didn’t pay attention), to see how the wagee reacted. The observing dogs wore a vest to monitor their heart rate, and were videotaped so behaviorists could look at their behaviors afterward. © Society for Science & the Public 2000 - 2013.

Keyword: Animal Communication; Aggression
Link ID: 18864 - Posted: 11.02.2013

A new report released today by the Institute of Medicine (IOM) may help dispel some common misconceptions about sport-related concussions in youth—for example, that wearing helmets can prevent them. First and foremost, however, it highlights the large gaps in knowledge that make it difficult for parents, coaches, and physicians to navigate decisions about prevention and treatment. The report also suggests where federal research agencies should focus their attention. The study, by a 17-member committee assembled by the Washington, D.C.-based IOM, which advises the government on health issues, comes amid growing concern about sports-related brain injuries. Although much of the attention has focused on adult professional athletes playing American football, health professionals have highlighted the need to understand risks among young athletes as well. To help clarify matters, a number of agencies, including the Centers for Disease Control and Prevention (CDC), the Department of Defense, and the Department of Education, asked IOM to conduct its study. The most glaring obstacle to understanding youth concussion at this point is a lack of data, the report finds. Most published research on sports-related concussions has been conducted in adults, and “there’s little-to-no information about concussions in youth,” particularly for ages 5 to 21, says panel member Susan Margulies, a bioengineer at the University of Pennsylvania. It’s dangerous to assume that findings in adults can be mapped onto children, she says, because of the changes that occur during brain development. “It’s possible that the threshold for injury might be different across different age ranges.” © 2013 American Association for the Advancement of Science

Keyword: Brain Injury/Concussion; Aggression
Link ID: 18858 - Posted: 10.31.2013

By Ajai Raj Football has become notorious for the degeneration it causes in players' brains. Now a preliminary study of soccer players has found that frequently hitting the ball with the head may adversely affect brain structure and cognition. The study imaged the brains of 37 amateur soccer players, 21 to 44 years old, and found that players who reported “heading the ball” more frequently had microstructural changes in the white matter of their brains similar to those observed in patients with traumatic brain injury. These players also performed poorly on cognitive tests, compared with players who reported heading the ball less. The study, published online in June in Radiology, found evidence of a threshold—1,800 headings—above which the effects on memory begin to manifest. Neuroradiologist Michael Lipton of the Albert Einstein College of Medicine of Yeshiva University, who led the study, says the findings may indicate that heading causes mild concussions, even when players do not show symptoms. The results are noteworthy but far from conclusive, comments Jonathan French, a neuropsychologist in the Sports Medicine Concussion Program at the University of Pittsburgh Medical Center, who was not involved in the study. “The majority of soccer players who are concussed don't have any functional problems in everyday life,” he says. The structural changes detected in the study, he points out, are "so microscopic that we don't know what they actually mean” for long-term function. Lipton agrees more work is needed to determine the significance of the brain changes, but he hopes to call attention to the potential risk because soccer is the most popular sport in the world. © 2013 Scientific American

Keyword: Brain Injury/Concussion; Aggression
Link ID: 18857 - Posted: 10.31.2013

By NELSON GRAVES Six years ago I suffered a stroke that forced me to relearn how to walk. The other day I ran a half-marathon. Strokes strike with stealth, but for me it was not entirely a surprise. During a physical in Milan in 2007, the doctor listened to my heart, then ordered an electrocardiogram. “Fair enough,” I reassured myself. “I’m 52 years old, and it’s no use taking anything for granted.” The nurse furrowed her brow as she studied the first read-out, then conducted a second, longer EKG. I put my shirt back on and returned to the doctor’s office. “I have some news for you,” he said. “You have atrial fibrillation. AF for short.” He wrote down the two words and explained they meant an irregular beating of the heart’s upper chambers. “It’s not life threatening. But it increases the risk of stroke six-fold.” I was too young to have a stroke. “I work 12-hour days, play squash three times a week and haven’t missed a day of work in 24 years,” I said. My attention piqued, I could now hear my heart’s irregular beat as I lay my head on my pillow. That must explain the dizziness when I get up at night to go to the bathroom. Or the fatigue at the end of a squash match. So when, on a September afternoon in Tokyo, my head began to spin wildly and I could hardly speak, I knew what was happening. After an ambulance ride to the hospital and an M.R.I., I heard the doctor say, “You’ve had a cerebral embolism.” That would be a stroke. Copyright 2013 The New York Times Company

Keyword: Stroke
Link ID: 18833 - Posted: 10.26.2013

Stroke deaths and illnesses are likely to continue shifting younger, global research suggests. In the Global and Regional Burden of Stroke in 1999-2010 study published in Thursday's issue of the medical journal The Lancet, researchers take a comprehensive look at stroke rates by country and region. "Stroke burden worldwide continues to increase," Prof. Valery Feigin, director of the National Institute for Stroke and Applied Neurosciences at AUT University in New Zealand said in an interview. "It's increasing at increased pace, more than we expected, disproportionately affecting low-to middle-income countries." The proportion of stroke in people younger than 65 is substantial, Feigin's team said. More than 83,000 children and youths aged 20 years and younger are affected by stroke annually. Feigin said the epidemic of obesity, and Type 2 diabetes in children and young people is increasing worldwide, which will be important risk factors for stroke 20 or 30 years down the road. If the trends in low-income and middle-income countries continue, by 2030 there will be almost 12 million stroke deaths and 70 million stroke survivors worldwide, the researchers projected. More than 90 per cent of strokes are preventable through lifestyle changes such as improving diet, quitting smoking, reducing salt and alcohol intake, increasing physical activity and managing stress, Feigin said.

Keyword: Stroke
Link ID: 18828 - Posted: 10.24.2013

by Hal Hodson American Football is a rough game, but the toll it takes on players' grey matter is only now becoming clear. For the first time, the number of head impacts on the playing field has been linked with cognitive problems and functional brain abnormalities in ex-footballers. Brain autopsies on retired National Football League (NFL) players have previously shown levels of damage that are higher than those in the general population. Now, this damage has been correlated with performance in tasks related to reasoning, problem solving and planning and highlights the worrying impact of repeated head trauma. To investigate the relationship between head trauma and cognitive damage, Adam Hampshire of Imperial College London, and his colleagues scanned the brains of 13 retired professional American football players and 60 people who had never played the sport, while they performed a series of cognitive tests in an fMRI machine. It wasn't an easy task: David Hubbard, who ran the tests at the Applied fMRI Institute in San Diego, California, says they initially had 15 ex-sportsmen, but two were too large to fit in the machine. The football players only showed modest deficits on the cognitive tasks, which included tests of planning, spatial awareness, memory and counting, however their brains had to work a lot harder to achieve the same results as the non-footballers. Regions of the frontal cortices that normally communicate with each other to handle reasoning and planning tasks were far less efficient in the footballers' brains. © Copyright Reed Business Information Ltd.

Keyword: Brain Injury/Concussion
Link ID: 18812 - Posted: 10.19.2013

Daniel Cossins It may not always seem like it, but humans usually take turns speaking. Research published today in Current Biology1 shows that marmosets, too, wait for each other to stop calling before they respond during extended vocal exchanges. The discovery could help to explain how humans came to be such polite conversationalists. Taking turns is a cornerstone of human verbal communication, and is common across all languages. But with no evidence that non-human primates 'converse' similarly, it was not clear how such behaviour evolved. The widely accepted explanation, known as the gestural hypothesis, suggests that humans might somehow have taken the neural machinery underlying cooperative manual gestures such as pointing to something to attract another person's attention to it, and applied that to vocalization. Not convinced, a team led by Daniel Takahashi, a neurobiologist at Princeton University in New Jersey, wanted to see whether another primate species is capable of cooperative calling. The researchers turned to common marmosets (Callithrix jacchus) because, like humans, they are prosocial — that is, generally friendly towards each other — and they communicate using vocalizations. After you The team recorded exchanges between pairs of marmosets that could hear but not see each other, and found that the monkeys never called at the same time. Instead, they always waited for roughly 5 seconds after a caller had finished before responding. © 2013 Nature Publishing Group

Keyword: Language; Aggression
Link ID: 18808 - Posted: 10.19.2013

Sending up the alarm when a predator approaches seems like a good idea on the surface. But it isn’t always, because such warnings might help the predator pinpoint the location of its next meal. So animals often take their audience into account when deciding whether or not to warn it of impending danger. And a new study in Biology Letters finds that the vulnerability of that audience matters, at least when we’re talking about baby birds and their parents. Tonya Haff and Robert Magrath of Australian National University in Canberra studied a local species, the white-browed scrubwren, by setting up an experiment to see if parents' reactions to predators changed when the babies were more vulnerable. Baby birds are vulnerable pretty much all the time but more so when they’re begging for food. That whining noise can lead a predator right to them. But a parent’s alarm call can shut them right up. Haff and Magrath began by determining that parent scrubwrens would respond normally when they heard recordings of baby birds. (They used recordings because those are more reliable than getting little chicks to act on cue.) Then they played those recordings or one of background noise near scrubwren nests. The role of the predator was played by a taxidermied pied currawong, with a harmless fake crimson rosella (a kind of parrot) used as a control. The mama and papa birds called out their “buzz” alarm more often when the pied currawong was present and the baby bird recording was being played. They barely buzzed when the parrot was present or only background noise was played. The parents weren’t alarm calling more just to be heard over the noise, the researchers say. If that were the case, then a second type of call — a contact “chirp” that mamas and papas give when approaching a nest — should also have become more common, which it didn’t. © Society for Science & the Public 2000 - 2013.

Keyword: Animal Communication; Aggression
Link ID: 18807 - Posted: 10.19.2013

Brian Owens Bats that nest inside curled-up leaves may be getting an extra benefit from their homes: the tubular roosts act as acoustic horns, amplifying the social calls that the mammals use to keep their close-knit family groups together. South American Spix’s disc-winged bats (Thyroptera tricolor) roost in groups of five or six inside unfurling Heliconia and Calathea leaves. The leaves remain curled up for only about 24 hours, so the bats have to find new homes almost every day, and have highly specialized social calls to help groups stay together. When out flying, they emit a simple inquiry call. Bats inside leaves answer with a more complex response call to let group members know where the roost is. Gloriana Chaverri, a biologist at the University of Costa Rica in Golfito, took curled leaves into the lab and played recorded bat calls through them, to see how the acoustics were changed by the tapered tubular shape of the leaves. “The call emitted by flying bats got really amplified,” she says, “while the calls from inside the leaves were not amplified as much.” Sound system The inquiry calls from outside the roost were boosted by as much as 10 decibels as the sound waves were compressed while moving down the narrowing tube — the same thing that happens in an amplifying ear trumpet. Most response calls from inside the leaf were boosted by only 1–2 decibels, but the megaphone shape of the leaf made them highly directional. The results are published today in Proceedings of the Royal Society B1. © 2013 Nature Publishing Group

Keyword: Hearing; Aggression
Link ID: 18791 - Posted: 10.16.2013

by Bruce Bower Babies may start to learn their mother tongues even before seeing their mothers’ faces. Newborns react differently to native and foreign vowel sounds, suggesting that language learning begins in the womb, researchers say. Infants tested seven to 75 hours after birth treated spoken variants of a vowel sound in their home language as similar, evidence that newborns regard these sounds as members of a common category, say psychologist Christine Moon of Pacific Lutheran University in Tacoma, Wash., and her colleagues. Newborns deemed different versions of a foreign vowel sound to be dissimilar and unfamiliar, the scientists report in an upcoming Acta Paediatrica. “It seems that there is some prenatal learning of speech sounds, but we do not yet know how much,” Moon says. Fetuses can hear outside sounds by about 10 weeks before birth. Until now, evidence suggested that prenatal learning was restricted to the melody, rhythm and loudness of voices (SN: 12/5/09, p. 14). Earlier investigations established that 6-month-olds group native but not foreign vowel sounds into categories. Moon and colleagues propose that, in the last couple months of gestation, babies monitor at least some vowels — the loudest and most expressive speech sounds — uttered by their mothers. © Society for Science & the Public 2000 - 2013

Keyword: Language; Aggression
Link ID: 18769 - Posted: 10.09.2013

By Helen Briggs BBC News The brain has a critical window for language development between the ages of two and four, brain scans suggest. Environmental influences have their biggest impact before the age of four, as the brain's wiring develops to process new words, say UK and US scientists. The research in The Journal of Neuroscience suggests disorders causing language delay should be tackled early. It also explains why young children are good at learning two languages. The scientists, based at King's College London, and Brown University, Rhode Island, studied 108 children with normal brain development between the ages of one and six. They used brain scans to look at myelin - the insulation that develops from birth within the circuitry of the brain. To their surprise, they found the distribution of myelin is fixed from the age of four, suggesting the brain is most plastic in very early life. Any environmental influences on brain development will be strongest in infanthood, they predict. This explains why immersing children in a bilingual environment before the age of four gives them the best chance of becoming fluent in both languages, the research suggests. BBC © 2013

Keyword: Language; Aggression
Link ID: 18768 - Posted: 10.09.2013

Smart, successful, and well-connected: a good description of Albert Einstein … and his brain. The father of relativity theory didn’t live to see modern brain imaging techniques, but after his death his brain was sliced into sections and photographed. Now, scientists have used those cross-sectional photos to reveal a larger-than-average corpus callosum—the bundle of nerve fibers connecting the brain’s two hemispheres. Researchers measured the thickness of the famous noggin’s corpus callosum (the lighter-colored, downward-curving region at the center of each hemisphere, above) at various points along its length, and compared it to MRIs from 15 elderly men and 52 young, healthy ones. The thickness of Einstein’s corpus callosum was greater than the average for both the elderly and the young subjects, the team reported online last week in the journal Brain. The authors posit that in Einstein’s brain, more nerve fibers connected key regions such as the two sides of the prefrontal cortex, which are responsible for complex thought and decision-making. Combined with previous evidence that parts of the physicist’s brain were unusually large and intricately folded, the researchers suggest that this feature helps account for his extraordinary gifts. © 2013 American Association for the Advancement of Science

Keyword: Intelligence; Aggression
Link ID: 18750 - Posted: 10.07.2013

By Lenny Bernstein, Joanna Leigh describes her life in black and white, before and after. Before the Boston Marathon bombing, she says, she had “just embarked on a really beautiful future” with a new doctoral degree in international development and a career as a consultant. Today, she says, she can’t work or drive and often gets lost, sometimes on her own block. Her vision is blurry, her hearing is diminished and her ears ring constantly. She struggles to cook dinner, do her laundry, fill out a form. Mostly, she sleeps. The cause of her difficulties, according to the physician who examined her, was a traumatic brain injury on April 15. But because Leigh, 39, walked home that day after she was knocked unconscious by the second bomb and never went to a hospital, she received just $8,000 from the One Fund charity for survivors. She said her medical and other expenses have reached $70,000. She is applying for disability payments and food stamps. One Fund payouts to everyone except 16 amputees and the families of the four people who were killed were based on the number of nights spent in the hospital. A single night was worth $125,000; 32 nights qualified victims for $948,000. The 143 people who were treated as outpatients received $8,000 each. In coming days, Leigh and four other attack survivors will petition the One Fund to develop a new plan for distributing the millions of dollars in donations the charity has received since the first payout. They are seeking a formula that takes into account injuries that were slow to reveal themselves. © 1996-2013 The Washington Post

Keyword: Brain Injury/Concussion
Link ID: 18736 - Posted: 10.03.2013

By KEN BELSON Football players as young as 7 sustain hits to the head comparable in magnitude to those absorbed by high school and adult players, and most of the hits are sustained in practices, not games, according to research to be released Wednesday. The findings, which may influence how youth football organizations handle training methods and rules, were included in four studies published by researchers at the Virginia Tech-Wake Forest University School of Biomedical Engineering and Sciences. The research, though limited, is considered by experts to be a step in the effort to address the relatively shallow understanding of the potential long-term effects of head trauma on young players. More than 25,000 football players from 8 to 19 years old are taken to emergency rooms seeking treatment for concussions every year, but most of the research on head injuries in football has focused on professional and college players. The new research, which was presented at the annual Biomedical Engineering Society conference this week, tracked about 120 players in Virginia and North Carolina from 7 to 18 over two seasons. Each young athlete wore six devices, known as accelerometers, in their helmets to measure the force, position and direction of the hits, and every practice and game was videotaped to determine how they occurred. To help determine any changes in brain structure and function, many of the players received magnetic resonance imaging brain scans before and after the season, and after they sustained a concussion. Some players also received magnetoencephalography scans, or MEG scans, to map their brain activity. © 2013 The New York Times Company

Keyword: Brain Injury/Concussion; Aggression
Link ID: 18698 - Posted: 09.25.2013

By Melissa Hogenboom Science reporter, BBC News Moving in time to a steady beat is closely linked to better language skills, a study suggests. People who performed better on rhythmic tests also showed enhanced neural responses to speech sounds. The researchers suggest that practising music could improve other skills, particularly speech. In the Journal of Neuroscience, the authors argue that rhythm is an integral part of language. "We know that moving to a steady beat is a fundamental skill not only for music performance but one that has been linked to language skills," said Nina Kraus, of the Auditory Neuroscience Laboratory at Northwestern University in Illinois. More than 100 teenagers were asked to tap their fingers along to a beat. Their accuracy was measured by how closely their responses matched the timing of a metronome. Next, in order to understand the biological basis of rhythmic ability, the team also measured the brainwaves of their participants with electrodes, a technique called electroencephalography. This was to observe the electrical activity in the brain in response to sound. Using this biological approach, the researchers found that those who had better musical training also had enhanced neural responses to speech sounds. In poorer readers this response was diminished. BBC © 2013

Keyword: Language; Aggression
Link ID: 18665 - Posted: 09.18.2013

By Joshua K. Hartshorne There are two striking features of language that any scientific theory of this quintessentially human behavior must account for. The first is that we do not all speak the same language. This would be a shocking observation were not so commonplace. Communication systems and other animals tend to be universal, with any animal of the species able to communicate with any other. Likewise, many other fundamental human attributes show much less variation. Barring genetic or environmental mishap, we all have two eyes, one mouth, and four limbs. Around the world, we cry when we are sad, smile when we are happy, and laugh when something is funny, but the languages we use to describe this are different. The second striking feature of language is that when you consider the space of possible languages, most languages are clustered in a few tiny bands. That is, most languages are much, much more similar to one another than random variation would have predicted. Starting with pioneering work by Joseph Greenberg, scholars have cataloged over two thousand linguistic universals (facts true of all languages) and biases (facts true of most languages). For instance, in languages with fixed word order, the subject almost always comes before the object. If the verb describes a caused event, the entity that caused the event is the subject ("John broke the vase") not the object (for example, "The vase shbroke John" meaning "John broke the vase"). In languages like English where the verb agrees with one of its subjects or objects, it typically agrees with the subject (compare "the child eats the carrots" with "the children eat the carrots") and not with its object (this would look like "the child eats the carrot" vs. "the child eat the carrots"), though in some languages, like Hungarian, the ending of the verb changes to match both the subject and object. © 2013 Scientific American

Keyword: Language
Link ID: 18664 - Posted: 09.18.2013

By Tina Hesman Saey About 10 percent of people prefer using their left hand. That ratio is found in every population in the world and scientists have long suspected that genetics controls hand preference. But finding the genes has been no simple task, says Chris McManus, a neuropsychologist at University College London who studies handedness but was not involved in the new research. “There’s no single gene for the direction of handedness. That’s clear,” McManus says. Dozens of genes are probably involved, he says, which means that one person’s left-handedness might be caused by a variant in one gene, while another lefty might carry variants in an entirely different gene. To find handedness genes, William Brandler, a geneticist at the University of Oxford, and colleagues conducted a statistical sweep of DNA from 3,394 people. Statistical searches such as this are known as genome-wide association studies; scientists often do such studies to uncover genes that contribute to complex diseases or traits such as diabetes and height. The people in this study had taken tests involving moving pegs on a board. The difference in the amount of time they took with one hand versus the other reflected how strongly left- or right-handed they were. A variant in a gene called PCSK6 was most tightly linked with strong hand preference, the researchers report in the Sept. 12 PLOS Genetics.. The gene has been implicated in handedness before, including in a 2011 study by the same research group. PCSK6 is involved in the asymmetrical positioning of internal organs in organisms from snails to vertebrates. © Society for Science & the Public 2000 - 2013

Keyword: Laterality; Aggression
Link ID: 18647 - Posted: 09.14.2013