Chapter 19. Language and Hemispheric Asymmetry

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By Helen Briggs Health editor, BBC News website The same genes drive maths and reading ability, research suggests. Around half of the genes that influence a child's aptitude for reading also play a role in how easily they learn maths, say scientists. The study of 12-year-old British twins from 3,000 families, reported in Nature Communications, adds to the debate about the role of genes in education. An education expert said the work had little relevance for public policy as specific genes had not been identified. Past research suggests both nature and nurture have a similar impact on how children perform in exams. One study found genes explained almost 60% of the variation in GCSE exam results. However, little is known about which genes are involved and how they interact. The new research suggests a substantial overlap between the genetic variations that influence mathematics and reading, say scientists from UCL, the University of Oxford and King's College London. But non-genetic factors - such as parents, schools and teachers - are also important, said Prof Robert Plomin of King's College London, who worked on the study. "The study does not point to specific genes linked to literacy or numeracy, but rather suggests that genetic influence on complex traits, like learning abilities, and common disorders, like learning disabilities, is caused by many genes of very small-effect size," he said. BBC © 2014

Keyword: Language; Aggression
Link ID: 19808 - Posted: 07.09.2014

By Smitha Mundasad Health reporter, BBC News Researchers have identified a gene that may put people at greater risk of strokes and heart attacks. Writing in PLOS ONE they say the gene fault may encourage the formation of blood clots - the ultimate cause of most heart attacks and strokes. Scientists hope gene tests may help doctors one day to pinpoint individuals more likely to suffer these conditions. But experts say lifestyle factors such as smoking and exercise have the greatest influence on risk. Around one in 10 people in the Caucasian population carries this variation of the gene, named PIA2. And researchers from King's College London reviewed more than 80 studies involving about 50,000 people - the largest analysis of this genetic fault to date. Threat to under-45s They found individuals with PIA2 were more likely to have a stroke - caused by a blood clot blocking blood supply to the brain - than those without the gene. Scientists calculate the gene increases a person's risk of having a stroke by 10-15%. But how significant this increase is depends on an individual's baseline risk - influenced by factors such as smoking, diet, weight and exercise, the scientists say. Heart attacks are caused by a blockage to the blood vessels that carry oxygen to the heart. More than 100,000 heart attacks are recorded in the UK each year And for people with two copies of the gene the risk rises by up to 70% from this baseline. In a second study published in the same journal, the scientists show PIA2 is also linked to an increased risk of heart attacks in people under 45. More research is needed to see whether this holds true for the whole population, they say. About 150,000 people have a stroke in the UK each year and more than 100,000 heart attacks are recorded annually. BBC © 2014

Keyword: Stroke; Aggression
Link ID: 19785 - Posted: 07.03.2014

From David Beckham’s infamous kick at France '98 to Luis Suárez chomping Giorgio Chiellini's shoulder in Brazil last week, the history of the World Cup is littered with moments of impulsive aggression that appear to defy all rational explanation. The story of human impulsivity stretches back deep into our evolutionary past. By nature, we are all prone to making quick, rash decisions that may lead to regret, and in some cases a four-month ban from international football. Impulsivity is actually a survival mechanism and was essential in the African savanna where our species evolved around a million and a half years ago. For our ancestors, the ability to make split-second decisions could make the difference between life and death. All of us have deep primal instincts but over the several hundred million years of evolution separating our reptilian ancestors from the first mammals, and eventually primates, the cognitive ability to exercise self-restraint has increased. While most living things make this decision purely as a trade-off between risk and reward, only humans can decide to exercise self-restraint on the basis of how they think they will be perceived by others – an ability that emerged some time in the past 100,000 years or so. “We evolved to be very social animals, living in large groups, and so we have developed inhibitory mechanisms in the more recently evolved parts of the prefrontal cortex,” explains Michael Price of the School of Social Sciences at the University of Brunel. “This is the social centre of the brain. Our big reason not to be impulsive is because of your reputation and how other people are going to judge you and perhaps ostracise you as we saw with Beckham in the aftermath of France ’98.” © 2014 Guardian News and Media Limited

Keyword: Aggression; Aggression
Link ID: 19784 - Posted: 07.03.2014

Learning a second language benefits the brain in ways that can pay off later in life, suggests a deepening field of research that specializes in the relationship between bilingualism and cognition. In one large Scottish test, researchers discovered archival data on 835 native speakers of English who were born in Edinburgh in 1936. The participants had been given an intelligence test at age 11 as part of standard British educational policy and many were retested in their early 70s. Those who spoke two or more languages had significantly better cognitive abilities on certain tasks compared with what would be expected from their IQ test scores at age 11, Dr. Thomas Bak of the Centre for Cognitive Aging and Cognitive Epidemiology at the University of Edinburgh reported in the journal Annals of Neurology. "Our results suggest a protective effect of bilingualism against age-related cognitive decline," independently of IQ, Bak and his co-authors concluded. It was a watershed study in 1962 by Elizabeth Peal and Wallace Lambert at McGill University in Montreal that turned conventional thinking on bilingualism on its head and set the rationale for French immersion in Canada. Psychologists at York University in Toronto have also been studying the effect of bilingualism on the brain across the lifespan, including dementia. They’ve learned how people who speak a second language outperform those with just one on tasks that tap executive function such as attention, selection and inhibition. Those are the high-level cognitive processes we use to multitask as we drive on the highway and juggle remembering the exit and monitoring our speed without getting distracted by billboards. © CBC 2014

Keyword: Language; Aggression
Link ID: 19781 - Posted: 07.02.2014

Carl Zimmer A novelist scrawling away in a notebook in seclusion may not seem to have much in common with an NBA player doing a reverse layup on a basketball court before a screaming crowd. But if you could peer inside their heads, you might see some striking similarities in how their brains were churning. That’s one of the implications of new research on the neuroscience of creative writing. For the first time, neuroscientists have used fMRI scanners to track the brain activity of both experienced and novice writers as they sat down — or, in this case, lay down — to turn out a piece of fiction. The researchers, led by Martin Lotze of the University of Greifswald in Germany, observed a broad network of regions in the brain working together as people produced their stories. But there were notable differences between the two groups of subjects. The inner workings of the professionally trained writers in the bunch, the scientists argue, showed some similarities to people who are skilled at other complex actions, like music or sports. The research is drawing strong reactions. Some experts praise it as an important advance in understanding writing and creativity, while others criticize the research as too crude to reveal anything meaningful about the mysteries of literature or inspiration. Dr. Lotze has long been intrigued by artistic expression. In previous studies, he has observed the brains of piano players and opera singers, using fMRI scanners to pinpoint regions that become unusually active in the brain. Needless to say, that can be challenging when a subject is singing an aria. Scanners are a lot like 19th-century cameras: They can take very sharp pictures, if their subject remains still. To get accurate data, Dr. Lotze has developed software that can take into account fluctuations caused by breathing or head movements. © 2014 The New York Times Company

Keyword: Language; Aggression
Link ID: 19756 - Posted: 06.21.2014

—By Indre Viskontas He might be fictional. But the gigantic Hodor, a character in the blockbuster Game of Thrones series, nonetheless sheds light on something very much in the realm of fact: how our ability to speak emerges from a complex ball of neurons, and how certain brain-damaged patients can lose very specific aspects of that ability. According to George R.R. Martin, who wrote the epic books that inspired the HBO show, the 7-foot-tall Hodor could only say one word—"Hodor"—and everyone therefore tended to assume that was his name. Here's one passage about Hodor from the first novel in Martin's series: Theon Greyjoy had once commented that Hodor did not know much, but no one could doubt that he knew his name. Old Nan had cackled like a hen when Bran told her that, and confessed that Hodor's real name was Walder. No one knew where "Hodor" had come from, she said, but when he started saying it, they started calling him by it. It was the only word he had. Yet it's clear that Hodor can understand much more than he can say; he's able to follow instructions, anticipate who needed help, and behave in socially appropriate ways (mostly). Moreover, he says this one word in many different ways, implying very different meanings: So what might be going on in Hodor's brain? Hodor's combination of impoverished speech production with relatively normal comprehension is a classic, albeit particularly severe, presentation of expressive aphasia, a neurological condition usually caused by a localized stroke in the front of the brain, on the left side. Some patients, however, have damage to that part of the brain from other causes, such as a tumor, or a blow to the head. ©2014 Mother Jones

Keyword: Language
Link ID: 19753 - Posted: 06.21.2014

By Michelle Roberts Health editor, BBC News online Scientists say they have devised a helmet that can quickly determine whether a patient has had a stroke. It could speed diagnosis and treatment of stroke to boost chances of recovery, the scientists say. The wearable cap bounces microwaves off the brain to determine whether there has been a bleed or clot deep inside. The Swedish scientists who made the device plan to give it to ambulance crews to test after successful results in early studies with 45 patients. When a person has a stroke, doctors must work quickly to limit any brain damage. If it takes more than four hours to get to hospital and start treatment, parts of their brain tissue may already be dying. But to give the best treatment, doctors first need to find out if the stroke is caused by a leaky blood vessel or one blocked by a clot. A computerised tomography (CT) scan will show this, but it can take some time to organise one for a patient, even if they have been admitted as an emergency to a hospital that has one of these scanners. Any delay in this "golden hour" of treatment opportunity could hamper recovery. To speed up the process, researchers in Sweden, from Chalmers University of Technology, Sahlgrenska Academy and Sahlgrenska University Hospital, have come up with a mobile device that could be used on the way to hospital. The helmet uses microwave signals - the same as the ones emitted by microwave ovens and mobile phones but much weaker - to build a picture of what is going on throughout the brain. BBC © 2014

Keyword: Stroke; Aggression
Link ID: 19741 - Posted: 06.17.2014

A selfie video that a 49-year-old Toronto-area woman took to show numbness and slurred speech she was experiencing helped doctors to diagnose her as having a mini-stroke, after she had earlier been given a diagnosis of stress. When Stacey Yepes’s face originally froze and she had trouble speaking in April, she remembered the signs of stroke from public service announcements. After the symptoms subsided, she went to a local emergency room, but the tests were clear and she was given tips on how to manage stress. The numbing sensation happened again as she left the hospital. When the left side of her body went numb while driving two days later, she pulled over, grabbed her smartphone and hit record. "The sensation is happening again," the Thornhill, Ont., woman says at the beginning of the video posted on YouTube by Toronto’s University Health Network. "It’s all tingling on left side," as she points to her lower lip, trying to smile. Yepes remembers that doctors said to breathe in and out and to try to manage stress, and she says she's trying. "I don’t know why this is happening to me." About a minute later, she shows that it’s hard to lift up her hand. "I think it was just to show somebody, because I knew it was not stress-related," she said in an interview. "And I thought if I could show somebody what was happening, they would have a better understanding." After going to Mount Sinai Hospital in downtown Toronto, Yepes was referred to Toronto Western Hospital’s stroke centre. © CBC 2014

Keyword: Stroke
Link ID: 19740 - Posted: 06.17.2014

As the popularity of soccer grows among children, doctors and researchers say the dangers of concussions need to be taken more seriously in the sport. When researchers at St. Michael's Hospital in Toronto reviewed the evidence on concussions and heading in soccer this winter, they found a higher incidence of concussions among females than males playing the world's most popular sport. Doctors warn that heading — purposely using the head to control and hit the ball — is a unique aspect of the beautiful game that needs more attention. Heading the ball isn’t necessarily going to cause an overt concussion with symptoms, but the accumulation of those impacts over time could cause difficulties with thinking, concentration and memory, said study author Monica Maher, a graduate student at the University of Toronto, and a former soccer goalkeeper. Maher doesn't want people to stop playing soccer or stop heading the ball. She does suggest limits on head exposure in younger children and padding on goal posts to prevent injury to the youngest players. ​Dr. David Robinson, a sports medicine physician at McMaster University in Hamilton, sees 10 to 15 concussions a week, including many related to soccer. "It's not a stretch to think that these chronic subconcussive blows may be softening the brain, injuring the brain over time," Robinson said. He calls it a step forward that balls are becoming lighter for young people. He reminds parents and coaches that if a concussion is suspected, it's best to remove an athlete from play. As for the differences in injury rates between males and females, Maher pointed to a few potential explanations: © CBC 2014

Keyword: Brain Injury/Concussion; Aggression
Link ID: 19736 - Posted: 06.16.2014

—By Indre Viskontas and Chris Mooney We've all been mesmerized by them—those beautiful brain scan images that make us feel like we're on the cutting edge of scientifically decoding how we think. But as soon as one neuroscience study purports to show which brain region lights up when we are enjoying Coca-Cola, or looking at cute puppies, or thinking we have souls, some other expert claims that "it's just a correlation," and you wonder whether researchers will ever get it right. Sam Kean But there's another approach to understanding how our minds work. In his new book, The Tale of the Dueling Neurosurgeons, Sam Kean tells the story of a handful of patients whose unique brains—rendered that way by surgical procedures, rare diseases, and unfortunate, freak accidents—taught us much more than any set of colorful scans. Kean recounts some of their unforgettable stories on the latest episode of the Inquiring Minds podcast. "As I was reading these [case studies] I said, 'That's baloney! There's no way that can possibly be true,'" Kean remembers, referring to one particularly surprising case in which a woman's brain injury left her unable to recognize and distinguish between different kinds of animals. "But then I looked into it, and I realized that, not only is it true, it actually reveals some important things about how the brain works." Here are five patients, from Kean's book, whose stories transformed neuroscience: 1. The man who could not imagine the future: Kent Cochrane (KC), pictured below, was a '70s wild child, playing in a rock band, getting into bar fights, and zooming around Toronto on his motorcycle. But in 1981, a motorcycle accident left him without two critical brain structures. Both of his hippocampi, the parts of the brain that allow us to form new long-term memories for facts and events in our lives, were lost. That's quite different from other amnesiacs, whose damage is either restricted to only one brain hemisphere, or includes large portions of regions outside of the hippocampus. Copyright ©2014 Mother Jones

Keyword: Attention; Aggression
Link ID: 19727 - Posted: 06.14.2014

by Bethany Brookshire Human vocal chords can produce an astonishing array of sounds: shrill and fearful, low and sultry, light and breathy, loud and firm. The slabs of muscle in our throat make the commanding sound of a powerful bass and a baby’s delightful, gurgling laugh. There are voices that must be taken seriously, voices that play and voices that seduce. And then there’s vocal fry. Bringing to mind celebrity voices like Kim Kardashian or Zooey Deschanel, vocal fry is a result of pushing the end of words and sentences into the lowest vocal register. When forcing the voice low, the vocal folds in the throat vibrate irregularly, allowing air to slip through. The result is a low, sizzling rattle underneath the tone. Recent studies have documented growing popularity of vocal fry among young women in the United States. But popular sizzle in women’s speech might be frying their job prospects, a new study reports. The findings suggest that people with this vocal affectation might want to hold the fry on the job market — and that people on the hiring side of the table might want to examine their biases. Vocal fry has been recognized since the 1970s, but now it’s thought of as a fad. Study coauthor Casey Klofstad, a political scientist at the University of Miami in Goral Gables, Fla., says that the media attention surrounding vocal fry generated a lot of speculation. “It is a good thing? Is it bad? It gave us a clear question we could test,” he says. Specifically, they wanted to study whether vocal fry had positive or negative effects on how people who used the technique were perceived. Led by Rindy Anderson from Duke University, the researchers recorded seven young men and seven young women speaking the phrase “Thank you for considering me for this opportunity.” Each person spoke the phrase twice, once with vocal fry and once without. Then the authors played the recordings to 800 participants ages 18 to 65, asking them to make judgments about the candidates based on voice alone. © Society for Science & the Public 2000 - 2013

Keyword: Language; Aggression
Link ID: 19718 - Posted: 06.10.2014

Damage to certain parts of the brain can lead to a bizarre syndrome called hemispatial neglect, in which one loses awareness of one side of their body and the space around it. In extreme cases, a patient with hemispatial neglect might eat food from only one side of their plate, dress on only one side of their body, or shave or apply make-up to half of their face, apparently because they cannot pay attention to anything on that the other side. Research published last week now suggests that something like this happens to all of us when we drift off to sleep each night. The work could help researchers to understand the causes of hemispatial neglect, and why it affects one side far more often than the other. It also begins to reveal the profound changes in conscious experience that take place while we fall asleep, and the brain changes that accompany them. Hemispatial neglect is a debilitating condition that occurs often in people who suffer a stroke, where damage to the left hemisphere of the brain results in neglect of the right half of space, and vice versa. It can occur as a result of damage to certain parts of the frontal lobes, which are involved in alertness and attention, and the parietal lobes, which process information about the body and its surrounding space. In clinical tests, patients with hemispatial neglect are typically unaware of all kinds of stimuli in one half of space – they fail to acknowledge objects placed in the affected half of their visual field, for example and cannot state the location of touch sensations on the affected side of their body. Some may stop using the limbs on the affected side, or even deny that the limbs belong to them. Patients with neglect can usually see perfectly well, but information from the affected side just does not reach their conscious awareness. © 2014 Guardian News and Media Limited

Keyword: Sleep; Aggression
Link ID: 19682 - Posted: 06.03.2014

Learning a second language can have a positive effect on the brain, even if it is taken up in adulthood, a University of Edinburgh study suggests. Researchers found that reading, verbal fluency and intelligence were improved in a study of 262 people tested either aged 11 or in their seventies. A previous study suggested that being bilingual could delay the onset of dementia by several years. The study is published in Annals of Neurology. The big question in this study was whether learning a new language improved cognitive functions or whether individuals with better cognitive abilities were more likely to become bilingual. Dr Thomas Bak, from the Centre for Cognitive Ageing and Cognitive Epidemiology at the University of Edinburgh, said he believed he had found the answer. Using data from intelligence tests on 262 Edinburgh-born individuals at the age of 11, the study looked at how their cognitive abilities had changed when they were tested again in their seventies. The research was conducted between 2008 and 2010. All participants said they were able to communicate in at least one language other than English. Of that group, 195 learned the second language before the age of 18, and 65 learned it after that time. The findings indicate that those who spoke two or more languages had significantly better cognitive abilities compared to what would have been expected from their baseline test. The strongest effects were seen in general intelligence and reading. The effects were present in those who learned their second language early, as well as later in life. BBC © 2014

Keyword: Language; Aggression
Link ID: 19679 - Posted: 06.02.2014

By GRETCHEN REYNOLDS A new study found subtle differences in the brains of college football players when compared to other students.Tim Larsen for The New York TimesA new study found subtle differences in the brains of college football players when compared to other students. The brains of college football players are subtly different from the brains of other students, especially if the players have experienced a concussion in the past, according to an important new brain-scan study that, while restrained in its conclusions, adds to concerns that sports-related hits to the head could have lingering effects on the brain, even among the young and healthy. Almost all of us have heard by now that concussions are more injurious than was once believed. It’s been widely reported that the autopsied brains of some professional football and hockey players who experienced repeated hits to the head showed signs of severe and progressive brain damage. Meanwhile, recent studies with living animals suggest that the brain may respond to even mild concussive blows with inflammatory and other reactions that, while designed to spur healing, could also contribute to tissue damage. But many fundamental questions about the long-term impacts of blows to the head during sports remain unanswered, including which portions of the brain are most affected, whether any brain changes also affect the ability to think, and if playing a contact sport might alter the structure and function of the brains of athletes, even ones who have never experienced a confirmed concussion. So, for a study published last week in JAMA, researchers at the Laureate Institute for Brain Research and the University of Tulsa, both in Tulsa, Okla., and other institutions, started delving into those issues by turning to the university’s Division I football team. Tulsa is, of course, in the heart of football country. But the researchers say they met no resistance from the school, team or players. © 2014 The New York Times Company

Keyword: Brain Injury/Concussion
Link ID: 19644 - Posted: 05.21.2014

By NATASHA SINGER Joseph J. Atick cased the floor of the Ronald Reagan Building and International Trade Center in Washington as if he owned the place. In a way, he did. He was one of the organizers of the event, a conference and trade show for the biometrics security industry. Perhaps more to the point, a number of the wares on display, like an airport face-scanning checkpoint, could trace their lineage to his work. A physicist, Dr. Atick is one of the pioneer entrepreneurs of modern face recognition. Having helped advance the fundamental face-matching technology in the 1990s, he went into business and promoted the systems to government agencies looking to identify criminals or prevent identity fraud. “We saved lives,” he said during the conference in mid-March. “We have solved crimes.” Thanks in part to his boosterism, the global business of biometrics — using people’s unique physiological characteristics, like their fingerprint ridges and facial features, to learn or confirm their identity — is booming. It generated an estimated $7.2 billion in 2012, according to reports by Frost & Sullivan. Making his rounds at the trade show, Dr. Atick, a short, trim man with an indeterminate Mediterranean accent, warmly greeted industry representatives at their exhibition booths. Once he was safely out of earshot, however, he worried aloud about what he was seeing. What were those companies’ policies for retaining and reusing consumers’ facial data? Could they identify individuals without their explicit consent? Were they running face-matching queries for government agencies on the side? Now an industry consultant, Dr. Atick finds himself in a delicate position. While promoting and profiting from an industry that he helped foster, he also feels compelled to caution against its unfettered proliferation. He isn’t so much concerned about government agencies that use face recognition openly for specific purposes — for example, the many state motor vehicle departments that scan drivers’ faces as a way to prevent license duplications and fraud. Rather, what troubles him is the potential exploitation of face recognition to identify ordinary and unwitting citizens as they go about their lives in public. Online, we are all tracked. But to Dr. Atick, the street remains a haven, and he frets that he may have abetted a technology that could upend the social order. © 2014 The New York Times Company

Keyword: Robotics
Link ID: 19630 - Posted: 05.18.2014

|By Sam Kean It is possible to take the idea of left/right differences within the brain too far: it’s not like one side of the brain talks or emotes or recognizes faces all by itself while the other one just sits there twiddling its neurons. But the left and right hemispheres of the human brain do show striking differences in some areas, especially with regard to language, the trait that best defines us as human beings. Scientists suspect that left-right specialization first evolved many millions of years ago, since many other animals show subtle hemispheric differences: they prefer to use one claw or paw to eat, for instance, or they strike at prey more often in one direction than another. Before this time, the left brain and right brain probably monitored sensory data and recorded details about the world to an equal degree. But there’s no good reason for both hemispheres to do the same basic job, not if the corpus callosum—a huge bundle of fibers that connects the left and right brain—can transmit data between them. So the brain eliminated the redundancy, and the left brain took on new tasks. This process accelerated in human beings, and we humans show far greater left/right differences than any other animal. In the course of its evolution the left brain also took on the crucial role of master interpreter. Neuroscientists have long debated whether certain people have two independent minds running in parallel inside their skulls. That sounds spooky, but some evidence suggests yes. For example, there are split-brain patients, who had their corpus callosums surgically severed to help control epilepsy and whose left and right brain cannot communicate as a result. Split-brain patients have little trouble drawing two different geometric figures at the same time, one with each hand. Normal people bomb this test. (Try it, and you’ll see how mind-bendingly hard it is.) Some neuroscientists scoff at these anecdotes, saying the claims for two separate minds are exaggerated. But one thing is certain: two minds or no, split-brain people feel mentally unified; they never feel the two hemispheres fighting for control, or feel their consciousness flipping back and forth. That’s because one hemisphere, usually the left, takes charge. And many neuroscientists argue that the same thing happens in normal brains. One hemisphere probably always dominates the mind, a role that neuroscientist Michael Gazzaniga called the interpreter. (Per George W. Bush, you could also call it “the decider.”) © 2014 Scientific American

Keyword: Laterality
Link ID: 19625 - Posted: 05.16.2014

by Nathan Collins There's a new twist in mental health. People with depression seem three times as likely as those without it to have two brain lobes curled around each other. The brains of people with depression can be physically different from other brains – they are often smaller, for example – but exactly why that is so remains unclear. In humans, some studies point to changes in the size of the hippocampi, structures near the back of the brain thought to support memory formation. "There are so many studies that show a smaller hippocampus in almost every psychiatric disorder," says Jerome Maller, a neuroscientist at the Monash Alfred Psychiatry Research Centre in Melbourne, Australia, who led the latest work looking at brain lobes. "But very few can actually show or hypothesize why that is." Maller thinks he has stumbled on an explanation. He had been using a brain stimulation technique known as transcranial magnetic stimulation as a therapy for antidepressant-resistant depression. This involved using fMRI scans to create detailed maps of the brain to determine which parts to stimulate. While pouring over hundreds of those maps, Maller noticed that many of them showed signs of occipital bending. This is where occipital lobes – which are important for vision – at the back of the brain's left and right hemispheres twist around each other. So he and his colleagues scanned 51 people with and 48 without major depressive disorder. They found that about 35 per cent of those with depression and 12.5 per cent of the others showed signs of occipital bending. The difference was even greater in women: 46 per cent of women with depression had occipital bending compared with just 6 per cent of those without depression. © Copyright Reed Business Information Ltd.

Keyword: Depression; Aggression
Link ID: 19617 - Posted: 05.15.2014

by Anil Ananthaswamy Children born with split brains – whereby the two hemispheres of their brains are not connected – can develop new brain wiring that helps to connect the two halves, according to brain scans of people with the condition. Such circuitry is not present in normal brains, and explains how some people with split brains can still maintain normal function. It also suggests that the developing brain is even more adaptable than previously thought. Research into people with split brains goes back to the 1960s, when neuroscientists studied people who had undergone brain surgery to treat particularly severe epilepsy. The surgery involved cutting the corpus callosum, the thick bundle of neuronal fibres that connects the brain's two halves. This disconnection prevented epileptic seizures spreading from one brain hemisphere to the other. The recipients of such split-brain surgery showed a form of disconnection syndrome whereby the two halves of their brains could not exchange information. For instance, if a patient touched an object with their left hand without seeing the object, they would be unable to name it. That is because sensory-motor signals from the left hand are processed in the right hemisphere. To put a name to the object, the tactile information from the hand has to reach the brain's left hemisphere, the seat of language. With the central connection between hemispheres severed, the object's naming information cannot be retrieved. Conversely, if that person were to touch an object with their right hand without seeing it, the sensory-motor signals from that hand would go to the left hemisphere, which hosts the brain's language centres, making naming the object easy. However, children born without a corpus callosum – and therefore whose two brain hemispheres are separated – can often pass such tactile naming tests when they are old enough to take them. Their brain hemispheres are obviously communicating, but it wasn't clear how. © Copyright Reed Business Information Ltd

Keyword: Laterality; Aggression
Link ID: 19609 - Posted: 05.13.2014

By Eric Niiler, Scientists studying head injuries have found something surprising: Genes may make some people more susceptible to concussion and trauma than others. A person’s genetic makeup, in fact, may play a more important role in the extent of injury than the number of blows a person sustains. While this research is still in its infancy, these scientists are working toward developing a blood test that may one day help a person decide — based on his her or her genetic predisposition — whether to try out for the football team, or perhaps take up swimming or chess instead. “Until now, all the attention has been paid to how hard and how often you get hit,” said Thomas McAllister, a professor of clinical psychiatry at the Indiana University School of Medicine. “No doubt that’s important. But it’s also becoming clear that’s it’s probably an interaction between the injury and the genetics of the person being injured.” This research is being spurred by fears that some athletes and many returning soldiers may face a lifetime of problems from head injuries. The National Football League agreed to settle a class-action concussion lawsuit by retired players last August for $765 million, although a judge rejected the agreement. In addition, the Pentagon estimates that 294,000 troops, many of whom served in Iraq and Afghanistan, suffered some kind of brain injury since 2000. “More and more we are noticing our servicemen are coming home with significant problems with brain function,” said Daniel Perl, a neuropathologist at the Center for Neuroscience and Regenerative Medicine at the Pentagon’s Uniformed Services University for Health Sciences in Bethesda. “We don’t know much about the biology of this. We need to get down to cellular level of resolution, how the brain starts to repair itself.” © 1996-2014 The Washington Post

Keyword: Brain Injury/Concussion; Aggression
Link ID: 19580 - Posted: 05.06.2014

By SAM KEAN UNTIL the past few decades, neuroscientists really had only one way to study the human brain: Wait for strokes or some other disaster to strike people, and if the victims pulled through, determine how their minds worked differently afterward. Depending on what part of the brain suffered, strange things might happen. Parents couldn’t recognize their children. Normal people became pathological liars. Some people lost the ability to speak — but could sing just fine. These incidents have become classic case studies, fodder for innumerable textbooks and bull sessions around the lab. The names of these patients — H. M., Tan, Phineas Gage — are deeply woven into the lore of neuroscience. When recounting these cases today, neuroscientists naturally focus on these patients’ deficits, emphasizing the changes that took place in their thinking and behavior. After all, there’s no better way to learn what some structure in the brain does than to see what happens when it shorts out or otherwise gets destroyed. But these case snippets overlook something crucial about people with brain damage. However glaring their deficits are, their brains still work like ours to a large extent. Most can still read and reason. They can still talk, walk and emote. And they still have the same joys and fears — facts that the psychological caricatures passed down from generation to generation generally omit. The famous amnesiac H. M., for instance, underwent radical brain surgery in 1953 and had most of the hippocampus removed on both sides of his brain; afterward, he seemed to lose the ability to form new long-term memories. Names, dates, directions to the bathroom all escaped him now. He’d eat two breakfasts if no one stopped him. Careful testing, however, revealed that H. M. could form new motor memories — memories of things like how to ride a bicycle — because they rely on different structures in the brain. This work established that memory isn’t a single, monolithic thing, but a collection of different faculties. © 2014 The New York Times Company

Keyword: Stroke; Aggression
Link ID: 19570 - Posted: 05.04.2014