A warning or mini-stroke occurs before one in every eight strokes, according to an Ontario study. A transient ischemic attack or TIA is a mild stroke that causes stroke symptoms such as sudden numbness of the face, arm or leg. The symptoms last for less than 24 hours and then resolve on their own without disabling neurological effects. Dr. Daniel Hackam of the University of Western Ontario in London, Ont., and his colleagues analyzed all patients hospitalized with a diagnosis of stroke between July 2003 and September 2007. Of the 16,400 patients reviewed, 2,032, or 12.4 per cent, had a TIA prior to the stroke that landed them in hospital, the team reported in Tuesday's issue of the journal Neurology. "These results illustrate the need for better risk assessment tools for preventing strokes before they occur," Hackam said in a release. "Other studies have shown that up to 80 per cent of strokes after TIA can be prevented when risk factors are managed intensively." Go to emergency for minor stroke People who did not have a TIA were more likely to have a more serious stroke than those who did have a warning stroke. © CBC 2009

Keyword: Stroke
Link ID: 13311 - Posted: 06.24.2010

Alison Abbott Two patients, partially blind because of damage to one side of their brain, were able to sense, and respond to, emotions expressed by people in pictures presented to their blind sides. A study by an international team of researchers found that the patients unconsciously twitched a facial muscle uniquely involved in smiling when a picture showed a happy person, and a muscle involved in frowning when the person depicted looked fearful1. The patients, both from the United Kingdom, have the very rare condition known as partial cortical blindness. Their eyes are intact but they have damage to the visual cortex on one side of their brain. This means that they cannot process information from the visual field on the opposite side of their nose. The scientists, who were led by Marco Tamietto and Beatrice de Gelder at Tilburg University in the Netherlands, say the results show that our spontaneous tendency to synchronize our facial expressions with those of other people in face-to-face situations — known as emotional contagion — occurs even if we cannot consciously see them. "This is interesting evidence that we can recognize the emotions of others without needing to be visually aware of them," says neuroscientist Christian Keysers, an expert in the neurophysiology of emotion at the University of Groningen, the Netherlands, who was not involved in the study. © 2009 Nature Publishing Group,

Keyword: Vision; Emotions
Link ID: 13310 - Posted: 06.24.2010

By Frans de Waal Two young bonobos exhibit the ape equivalent of the human laugh, a “play face,” which is accompanied by laugh-like panting sounds. Just as in humans, if one ape laughs others usually do as well, especially during wrestling and tickling games. Frans de Waal One morning, the principal’s voice sounded over the intercom of my high school with the shocking announcement that a popular teacher of French had just died in front of his class. Everyone fell silent. While the headmaster went on to explain that the teacher had suffered a heart attack, I couldn’t keep myself from a laughing fit. To this day, I feel embarrassed. What is it about laughter that makes it unstoppable even if triggered by inappropriate circumstances? Extreme bouts of laughter are awkward: they involve loss of control, shedding of tears, gasping for air, leaning on others, and even wetting of pants while rolling on the floor! What weird trick has been played on our linguistic species, that we express ourselves with stupid “ha ha ha!” sounds? Why don’t we leave it at a cool “That was funny!”? Philosophers who regard a sense of humor as one of humanity’s finest achievements may find it puzzling that it is expressed with the sort of crude abandon associated with mere animals. But laughter is an inborn, universal human trait, one that we share with our closest relatives, the apes (see “The Laughing Species,” December 2000-January 2001). © 2008–2009 Natural History Magazine, Inc.

Keyword: Emotions; Evolution
Link ID: 13309 - Posted: 06.24.2010

Physiologically, why is the sound of fingernails on a blackboard so unnerving? Is this effect particular to human beings, or are other creatures similarly affected? —Rowan Snyder, via e-mail Neuroscientist Josh McDermott of New York University explains: Probably a couple of factors combine to make such sounds unpleasant. The first, perhaps unsurprisingly, is the presence of high frequencies. The range between two and four kilohertz—approximately that covered by the highest octave of a standard piano—seems to contribute the most to the nastiness of the sound. It is unclear why people tend to find these frequencies unpleasant, but we know that noise-induced hearing loss most commonly occurs in roughly this region, so it is conceivable that the aversive reaction partly reflects the ear’s vulnerability. The spectrum of screeching sounds is also much noisier than that of an instrument; that is, there is a strong random component to the sound. The noisiness probably results from the fingernails repeatedly catching on part of the chalkboard surface before sliding forward. This catching and sliding also causes rapid fluctuations in intensity, giving the sound a “rough” character. Roughness is known to be unpleasant—car manufacturers, who aim to produce minimally unpleasant engine noise, for instance, find that smooth sounds with minimal variation in intensity are preferred by listeners over those that are rough. It’s a bit harder to say why sound roughness is considered unpleasant—as far as we know it is not harmful to the ears.

Keyword: Hearing
Link ID: 13308 - Posted: 06.24.2010

By ANAHAD O’CONNOR THE FACTS This familiar claim is the stuff of many a Hollywood story line — like “Daredevil,” in which a lawyer’s sudden blindness heightens his other senses and turns him into a superhero. Studies suggest that the story is more fact than fantasy. In one series of studies, neuroscientists at McGill University tested blind and sighted subjects for pitch perception and their ability to locate sounds. The blind subjects generally scored higher, which came as little surprise — until the scientists discovered that precisely when the subjects had become blind affected their performance. Those who were born blind did best, those who became blind as small children were slightly behind, and those who lost their vision after age 10 did no better than the sighted subjects. The implication was that a young brain could be rewired so that visual-processing areas were used for other purposes. Perhaps the strongest evidence of that was shown in brain-imaging studies, in which scientists found that blind subjects who were best able to locate sound were engaging both the auditory and the visual areas of the cortex. Blind subjects who scored low, as well as sighted subjects, had little or no activity in the visual lobe. Other studies have had similar results with odor discrimination and tactile sensation. THE BOTTOM LINE Research suggests that at least in some circumstances, blindness can heighten other senses. Copyright 2009 The New York Times Company

Keyword: Vision; Hearing
Link ID: 13307 - Posted: 06.24.2010

By Stephen Smith Even now, 11 months, three weeks, and four days since smoking her last, she hears the siren song of the cigarette beckoning. “I still have the craving, it’s true,’’ said Monica Collins, the syndicated newspaper columnist who was so fully under the spell of cigarettes that, by her own reckoning, it took eight attempts before she finally stopped puffing. “There are times I know I’m going to be doing a lot of errands and in my car and going here and there, and I say, ‘Oh, God. I would love to have a cigarette.’ ’’ But she doesn’t. Somehow, this time - maybe it was the nicotine-replacement patch, maybe the counseling - Collins resisted the call of the cigarette. But there is no denying: The stranglehold nicotine places on smokers can sometimes prove insurmountable. Ask Jerry Remy, the Red Sox TV analyst who acknowledged last month that, despite enduring lung cancer, he still falls prey to the occasional impulse to smoke. Ask Barack Obama, who signed a landmark law regulating tobacco in June and, a day later, conceded in a presidential press conference that he has episodically “fallen off the wagon.’’ And then there was Patrick Swayze, stricken with pancreatic cancer and captured in haunting photos with a lit cigarette perched on his lips. The failure to quit, research has shown, has nothing to do with weakness of will. Nicotine, the primary addictive agent in tobacco, steals into the brain, setting on fire circuitry that regulates our sense of pleasure. © 2009 NY Times Co.

Keyword: Drug Abuse
Link ID: 13306 - Posted: 06.24.2010

By Robert Roy Britt The moon holds a mystical place in the history of human culture, so it's no wonder that many myths — from werewolves to induced lunacy to epileptic seizures — have built up regarding its supposed effects on us. "It must be a full moon," is a phrase heard whenever crazy things happen and is said by researchers to be muttered commonly by late-night cops, psychiatry staff and emergency room personnel. It's been a long time since the Big Cheese revealed any new secrets as important as this week's announcement that traces of water exist all across its surface. Coincidentally, a study this week found zero connection between the full moon and surgery outcomes. In fact a host of studies over the years have aimed at teasing out any statistical connection between the moon — particularly the full moon — and human biology or behavior. The majority of sound studies find no connection, while some have proved inconclusive, and many that purported to reveal connections turned out to involve flawed methods or have never been reproduced. Reliable studies comparing the lunar phases to births, heart attacks, deaths, suicides, violence, psychiatric hospital admissions and epileptic seizures, among other things, have over and over again found little or no connection. © 2009 Space.com

Keyword: Biological Rhythms
Link ID: 13305 - Posted: 06.24.2010

By PAM BELLUCK Blindness first began creeping up on Barbara Campbell when she was a teenager, and by her late 30s, her eye disease had stolen what was left of her sight. Reliant on a talking computer for reading and a cane for navigating New York City, where she lives and works, Ms. Campbell, now 56, would have been thrilled to see something. Anything. Now, as part of a striking experiment, she can. So far, she can detect burners on her stove when making a grilled cheese, her mirror frame, and whether her computer monitor is on. She is beginning an intensive three-year research project involving electrodes surgically implanted in her eye, a camera on the bridge of her nose and a video processor strapped to her waist. The project, involving patients in the United States, Mexico and Europe, is part of a burst of recent research aimed at one of science’s most-sought-after holy grails: making the blind see. Some of the 37 other participants further along in the project can differentiate plates from cups, tell grass from sidewalk, sort white socks from dark, distinguish doors and windows, identify large letters of the alphabet, and see where people are, albeit not details about them. Copyright 2009 The New York Times Company

Keyword: Vision; Robotics
Link ID: 13304 - Posted: 06.24.2010

By BENOIT DENIZET-LEWIS Austin didn’t know what to wear to his first gay dance last spring. It was bad enough that the gangly 13-year-old from Sand Springs, Okla., had to go without his boyfriend at the time, a 14-year-old star athlete at another middle school, but there were also laundry issues. “I don’t have any clean clothes!” he complained to me by text message, his favored method of communication. When I met up with him an hour later, he had weathered his wardrobe crisis (he was in jeans and a beige T-shirt with musical instruments on it) but was still a nervous wreck. “I’m kind of scared,” he confessed. “Who am I going to talk to? I wish my boyfriend could come.” But his boyfriend couldn’t find anyone to give him a ride nor, Austin explained, could his boyfriend ask his father for one. “His dad would give him up for adoption if he knew he was gay,” Austin told me. “I’m serious. He has the strictest, scariest dad ever. He has to date girls and act all tough so that people won’t suspect.” Austin doesn’t have to play “the pretend game,” as he calls it, anymore. At his middle school, he has come out to his close friends, who have been supportive. A few of his female friends responded that they were bisexual. “Half the girls I know are bisexual,” he said. He hadn’t planned on coming out to his mom yet, but she found out a week before the dance. “I told my cousin, my cousin told this other girl, she told her mother, her mother told my mom and then my mom told me,” Austin explained. “The only person who really has a problem with it is my older sister, who keeps saying: ‘It’s just a phase! It’s just a phase!’ ” Copyright 2009 The New York Times Company

Keyword: Sexual Behavior; Development of the Brain
Link ID: 13303 - Posted: 06.24.2010

The brain never sits idle. Whether we are awake or asleep, watch TV or close our eyes, waves of spontaneous nerve signals wash through our brains. Researchers at the Salk Institute for Biological Studies studying visual attention have discovered a novel mechanism that explains how incoming sensory signals make themselves heard amidst the constant background rumblings so they can be reliably processed and passed on. "We live with the illusion that our visual system processes all the information that is available in the visual scene in a single glimpse," says John H. Reynolds, Ph.D., an associate professor in the Systems Neurobiology Laboratory at the Salk Institute and senior author of the current study. "In reality, there is far too much detail in a typical scene for the visual system to take it in all at once. So our perception of the world around us is in a sense pieced together from what we pay attention to." Researchers had known for some time that paying attention to visual details increases the firing rate of neurons tuned for attended stimulus. Until now, it was assumed that these attention-dependent increases in neural activity were the primary cause of the improvement in perceptual discrimination that we experience when we focus a sensory stimulus. The findings of the Salk researchers, published in the September 24, 2009 issue of the journal Neuron, reveal that the uptick in the firing rate is only a small part of the story. "What we found is that attention also reduces background activity," says postdoctoral researcher and first author Jude Mitchell, Ph.D. "We estimate that this noise reduction increases the fidelity of the neural signal by a factor that is as much as four times as large as the improvement caused by attention-dependent increases in firing rate. This reduction in noise may account for as much as 80% of the attention story." © 2009 Eureka! Science News

Keyword: Attention
Link ID: 13302 - Posted: 06.24.2010

By R. Douglas Fields Clinton didn’t inhale, Obama did—and maybe Reagan should have. New research suggests that THC, the chemical that gives marijuana its mind-bending properties, kills developing neurons, yet oddly, the same chemical saves neurons in adults with Alzheimer’s disease. “Marijuana is not the ‘soft drug’ people like to think it is,” says neuro­pharmacologist Veronica Campbell of Trinity College in Dublin, whose latest study uncovered the harmful effects of THC on young neurons. When Campbell and her co-workers treated brain cells from newborn or adolescent rats with THC, the neurons died, but THC did not have such deadly effects on neurons taken from adult rats. In fact, work from other labs shows that THC benefits adult neurons. “We don’t know why,” Campbell says. Several possi­bilities are being investigated for this “Jekyll and Hyde” effect. Marijuana, like tobacco and opium, has powerful effects on the brain because certain compounds in the plant happen to have a chemical resemblance to naturally occurring substances in the body. Called endocannabinoids, these natural chemicals regulate important brain functions by controlling synapses in neural circuits that process thought and perception. According to several recent studies, these chemicals have many other functions in the brain and immune system, too—including regulating development and aiding survival of young neurons, as well as controlling the wiring of neurons into circuits for learning and memory. Smoking marijuana during the period of life when the brain is still developing obscures these critical chemical signals, Campbell suspects. © 1996-2009 Scientific American Inc.

Keyword: Drug Abuse; Pain & Touch
Link ID: 13301 - Posted: 06.24.2010

By Charles Q. Choi By carefully analyzing brain activity, scientists can tell what number a person has just seen, research now reveals. They can similarly tell how many dots a person was presented with. Past investigations had uncovered brain cells in monkeys that were linked with numbers. Although scientists had found brain regions linked with numerical tasks in humans — the frontal and parietal lobes, to be exact — until now patterns of brain activity linked with specific numbers had proven elusive. Story continues below ↓advertisement | your ad here Scientists had 10 volunteers watch either numerals or dots on a screen while a part of their brain known as the intraparietal cortex was scanned — it's a region of the parietal lobe especially linked with numbers. They next rigorously analyzed brain activity to decipher which patterns might be linked with the numbers the volunteers had observed. When it came to small numbers of dots, the researchers found that brain activity patterns changed gradually in a way that reflected the ordered nature of the numbers. For example, one might be able to conclude that the pattern for six is between that for five and seven. In the case of the numerals, the researchers could not detect this same gradual change. This suggests their methods simply might not be sensitive enough to detect this progression yet, or that these symbols are, in fact, coded as more precise, discrete entities in the brain. © 2009 LiveScience.com.

Keyword: Miscellaneous
Link ID: 13300 - Posted: 06.24.2010

The brains of people who lost weight and kept it off responded differently to images of foods like ice cream compared to normal-weight individuals or those who regained the pounds, according to a new U.S. study. The brains of people who lost weight and kept it off responded differently to images of foods like ice cream compared to normal-weight individuals or those who regained the pounds, according to a new U.S. study. (HO, California Walnuts/Canadian Press) People who lose weight and keep it off may have different brain activity patterns than those who pack the pounds back on, according to a new U.S. study. The researchers, whose findings are in the October issue of the American Journal of Clinical Nutrition, monitored blood flow in the brains of people who successfully maintained their weight loss, as well as obese or normal-weight individuals. "Our findings shed some light on the biological factors that may contribute to weight loss maintenance," said the study's lead author, Jeanne McCaffery, of The Miriam Hospital's Weight Control and Diabetes Research Center in Miami. "They also provide an intriguing complement to previous behavioural studies that suggest people who have maintained a long-term weight loss monitor their food intake closely and exhibit restraint in their food choices," she added in a release. On average, people who participate in behavioural weight-loss programs lose eight to 10 per cent of their weight during the first six months and maintain two-thirds of that at the one-year followup, the researchers said. © CBC 2009

Keyword: Obesity
Link ID: 13299 - Posted: 06.24.2010

Dave Munger A member of my family died as a result of her alcohol abuse in her early 20s, leaving two children to be raised by their father. Clearly her addiction was horrible, and if it could have been prevented, many people would have been spared a lot of anguish. But consider the case of an independently wealthy man, living alone, with no dependents. He sits around his mansion all day, playing video games and freely sampling from his vast storehouse of illicit drugs. He’s just enjoying himself and he’s not directly hurting anyone. Is he a society-menacing addict? That’s the scenario presented by “DrugMonkey,” an NIH-funded biomedical research scientist who blogs anonymously at ScienceBlogs so that he can candidly assess the research of his peers. Two weeks ago he discussed an August study published in the journal Addiction that attempts to define clinical dependence on the rave-fave drug “Ecstasy,” or MDMA. We often think of true addicts as street junkies who prostitute themselves or steal from others to support their habits, but in reality there’s a wide variety of behaviors associated with abusing mind-altering substances. They can range from the casual drinker who sometimes has a few too many martinis, to the pothead who still lives in his mother’s basement, to a talk-show host zoned out on antidepressants. The American Psychiatric Association’s DSM-IV-TR is the reference most doctors use to diagnose mental disorders, and it offers two definitions of problems relating to recreational drug use. The first, “substance abuse,” simply suggests that abuse is any use of a substance that leads to physical, mental, social, or legal harm to oneself or to others. The second, “substance dependence,” is what we more commonly think of as addiction and includes a list of seven criteria, only three of which are needed to qualify. ©2005-2009 Seed Media Group LLC.

Keyword: Drug Abuse
Link ID: 13298 - Posted: 06.24.2010

by Jessica Hamzelou A lack of sleep could help toxic plaques develop in the brain, accelerating the progression of Alzheimer's disease. David Holtzman looked at how sleep affected the levels of beta-amyloid protein in mice and humans. This protein causes plaques to build up in the brain, which some think cause Alzheimer's disease by killing cells. Holtzman's group found that beta-amyloid levels were higher in mouse brains when the mice were awake than when they were sleeping. Lack of sleep also had an effect on plaque levels: when the mice were sleep-deprived – forced to stay awake for 20 hours of the day – they developed more plaques in their brains. Holtzman also tried sending the mice to sleep with a drug that is being trialled for insomnia, called Almorexant. This reduced the amount of plaque-forming protein. He suggests that sleeping for longer could limit the formation of plaques, and perhaps block it altogether. The group also measured levels of beta-amyloid in the cerebrospinal fluid of 10 healthy men, both at night and during the day. Levels were lower at night, suggesting that sleep might also help keep levels of the plaque protein low in humans. © Copyright Reed Business Information Ltd.

Keyword: Alzheimers; Sleep
Link ID: 13297 - Posted: 06.24.2010

By Susan Gaidos Mention hypnosis, and the image that springs to mind is a caped magician swinging a pocket watch, seducing otherwise sensible people into barking like dogs. But hypnosis is more than a stage show act. For years, psychologists have used it to help patients calm preflight jitters, get a good night’s sleep or chuck a cigarette habit. Hypnosis even has uses in mainstream medicine for reducing the side effects of cancer treatments and helping patients cope with pain. Some physicians routinely employ hypnosis as an adjunct to mainstream anesthesia to help block pain during surgery or childbirth. Most recently, hypnosis has advanced from stage and clinic into the laboratory. It is now used as a research tool to temporarily create hallucinations, compulsions, delusions and certain types of seizures in the lab so that these phenomena can be investigated in detail. Such studies may lead to more effective treatments for a number of psychiatric and neurological disorders, assert psychologists Peter W. Halligan and David Oakley in the June issue of Trends in Cognitive Sciences. Other scientists, intrigued by the many practical uses of hypnosis, are striving to figure out how it works. Using the latest neuroimaging tools, these scientists are getting a look at what goes on in the hypnotized brain. The findings are mesmerizing. © Society for Science & the Public 2000 - 2009

Keyword: Pain & Touch; Attention
Link ID: 13296 - Posted: 06.24.2010

By Cassandra Willyard Each fall, hundreds of millions of newly hatched monarch butterflies flit from the fields and forests in eastern regions of Canada and the United States to the alpine fir forests of central Mexico, converging on the same spot to wait out the winter. Scientists don't know exactly how these insects find their way, but a new study shows that, to navigate, the butterflies rely on biological clocks. Oddly enough, the clocks are located in their antennae, not in their brains as previously thought. Migrating monarchs rely on the sun to maintain a constant heading. Because the sun drifts from east to west as the day wears on, the butterflies need a timekeeping device to help them compensate for its movement. Monarchs have a biological clock in their brains that relies on light cues to regulate their sleep-wake cycles and monitor day length. Scientists assumed they also used this clock to navigate. But the new study shows that the antennae possess a separate clock that controls time compensation. "That was a huge surprise," says Steven Reppert, a neurobiologist at the University of Massachusetts Medical School in Worcester and co-author of the new study. Reppert and his colleagues began studying antennae because they thought the appendages might assist migration in other ways--by allowing the butterflies to pick up certain scents, for example. They soon saw something surprising. When they clipped the antennae off about 30 migrating monarchs and put them in a flight simulator, which can track the direction they try to fly, the butterflies were disoriented. Whereas butterflies with antenna flew south to southeast, those with clipped antennae flew in random directions, although each individual hewed to its heading fairly consistently. © 2009 American Association for the Advancement of Science

Keyword: Biological Rhythms; Animal Migration
Link ID: 13295 - Posted: 06.24.2010

IT HAS long been a puzzle that girls who grow up without their fathers at home reach sexual maturity earlier than girls whose fathers live with them. For years, absent fathers have taken the blame for this, because growing up quickly has negative consequences for girls. For example, early-bloomers are more likely to suffer depression, hate their bodies, engage in risky sex and get pregnant in their teen years. It could be a simple matter of not having as many eyes, particularly suspicious fatherly ones, watching over daughters. Or it could be a complicated physiological response to stress, in which girls adapt their reproductive strategy to their circumstances. If life is harsh, the theory goes, maybe they need to get their babies into the world as quickly as possible. The animal world suggests that the effect is not restricted to humans. Young mice, pigs, goats and even a few primates get signals from their kin which inhibit sexual development; a strange male in their midst, by contrast, really speeds things up. Research in humans has shown that girls growing up with stepfathers mature even more quickly than fatherless girls and that stepbrothers have a measurable effect too. However, Jane Mendle of the University of Oregon and her colleagues have suggested another putative cause: genes. Specifically, the same genes that might make a dad more likely to leave his family could be behind early sexual development as well. The researchers came to their conclusion after analysing data collected through the American National Longitudinal Survey of Youth. Dr Mendle looked at 1,382 boys and girls, each of whom was related to at least one other subject through their mother. Most of the mothers were pairs of sisters, but some were identical twins or first cousins raised as sisters. © The Economist Newspaper Limited 2009.

Keyword: Sexual Behavior; Genes & Behavior
Link ID: 13294 - Posted: 06.24.2010

In 2006, concern over the welfare of his family caused Dario Ringach to stop using animals in his research. A neuroscientist at the University of California in Los Angeles (UCLA), Ringach had been receiving threats from animal-rights extremists over his experiments involving primates. Then, an undetonated firebomb was left next door to the house of a colleague, apparently because the activists had the wrong address. After three years of keeping a low profile, Ringach is now trying to raise public support for the use of animals in research. This month, he published a commentary on the subject in the Journal of Neuroscience1 and a letter to the editor in the Journal of Neurophysiology2 in which he calls on scientists to publicly support such research. His coauthor on both was David Jentsch, a neuropsychopharmacologist at UCLA whose work involves primates and whose car was firebombed earlier this year. Nature spoke with Ringach about his concerns. You say that animal-rights extremists are winning. Why? You can see this in a recent Pew research survey on public opinion on science. Only 52% of the broad public supports biomedical research involving animals. And over the years, this has consistently declined. What is behind this trend? A lot of organizations at different levels have had a tremendous impact — from work that the Humane Society of the United States [based in Washington DC] has been doing in exposing failures in the food industry, to work that PETA [People for the Ethical Treatment of Animals, based in London] is doing in trying to reach out to children very early. © 2009 Nature Publishing Group

Keyword: Animal Rights
Link ID: 13293 - Posted: 06.24.2010

By Katherine Ellison For decades, attention-deficit hyperactivity disorder has sparked debate. Is it a biological illness, the dangerous legacy of genes or environmental toxins, or a mere alibi for bratty kids, incompetent parents and a fraying social fabric? With 4.5 million U.S. children having received a diagnosis of the disorder -- and more than half of them taking prescription drugs to control it -- the question has divided doctors and patients, parents and teachers, and mothers and fathers. Scientists maintain that they've been narrowing in on the origins and mechanics of disabling distraction, while gathering increasing evidence that ADHD is as real as such less controversial disorders as Down syndrome and schizophrenia. Their most recent progress is described in a Sept. 9 report in the Journal of the American Medical Association, based on a new study that indicates a striking difference in the brain's motivational machinery in people with ADHD symptoms. "This is another big piece in the puzzle saying that there is something there, that this is not simply a matter of anxious parents," said James Swanson, a co-author of the report and a developmental psychologist based at the University of California at Irvine. The JAMA study said that, compared with a group of healthy subjects, brain scans of 53 adults with ADHD revealed a flaw in the way they process dopamine, which among other things, alerts people to new information and helps them anticipate pleasure and rewards. Swanson speculated that people with ADHD may even have a net deficit of dopamine. © 2009 The Washington Post Company

Keyword: ADHD; Brain imaging
Link ID: 13292 - Posted: 06.24.2010