By RONALD PIES, M.D. Harry was one of the lucky ones. After a lifetime of schizophrenia — hallucinations, hospitalizations and all the attendant miseries — he was a genuinely new man. This was about 20 years ago, and clozapine — then viewed as a miracle antipsychotic drug — seemed to have wrought some deep, transforming magic. True, he had put on 20 pounds and complained of mild drowsiness. But the crippling fears and fearsome voices had been quieted. We were able to discharge him from the hospital and arrange for placement in a neighborhood residence. At his first outpatient appointment, Harry looked cheerful. He seemed to be adjusting to a life of relative normalcy. This was more than I had hoped for, given his disease and its devastation. When the German psychiatrist Emil Kraepelin described what we now recognize as schizophrenia, he called it “dementia praecox” — premature dementia. For decades, the condition was thought to have an inevitable downhill course, much as we still see with Alzheimer’s disease. Even during my residency in the early 1980s, most of us were gloomy about schizophrenia. We now believe that schizophrenia comprises several different disease processes and often has a more benign course. We have begun to speak not only of remission, but even of recovery — and hope. Copyright 2009 The New York Times Company

Keyword: Schizophrenia
Link ID: 12823 - Posted: 06.24.2010

Scientists have uncovered genetic evidence suggesting the sleep disorder narcolepsy is linked to a fault in the immune system's "foot soldier" cells. It suggests these T-cells may cause the condition by attacking cells in the sleep centres of the brain. Narcolepsy, which causes extreme daytime sleepiness and sudden muscle weakness, has previously been linked to a malfunctioning immune system. The Stanford University research appears in the journal Nature Genetics. Narcolepsy is a mysterious, uncommon condition that can be very distressing for those who have it. It can trigger "sleep attacks" without any warning during any normal activity. In addition, some people can experience "cataplexy", where strong emotions such as anger, surprise, or laughter can trigger an instant loss of muscle strength, which, in some cases, can cause collapse. There is currently no cure for narcolepsy, only ways to minimise symptoms such as taking frequent, brief naps evenly spaced throughout the day. The condition has previously been linked to depletion of cells deep in the regulatory regions of the brain. But lead researcher Dr Emmanuel Mignot said while previous research had only suggested a link with a fault in the immune system, the latest study provided firm evidence. The Stanford team carried out an extensive genetic analysis to identify specific areas of the genome which appeared to be linked to the condition. They pinpointed three specific genetic variants in the same gene in people with European and Asian ancestry that appeared to be associated with an increased susceptibility for narcolepsy. The gene in question plays a key role in the functioning of an important receptor used by T-cells to recognise foreign proteins in the body. (C)BBC

Keyword: Narcolepsy; Neuroimmunology
Link ID: 12822 - Posted: 05.05.2009

Drinking water which contains the element lithium may reduce the risk of suicide, a Japanese study suggests. Researchers examined levels of lithium in drinking water and suicide rates in the prefecture of Oita, which has a population of more than one million. The suicide rate was significantly lower in those areas with the highest levels of the element, they wrote in the British Journal of Psychiatry. High doses of lithium are already used to treat serious mood disorders. But the team from the universities of Oita and Hiroshima found that even relatively low levels appeared to have a positive impact of suicide rates. Levels ranged from 0.7 to 59 micrograms per litre. The researchers speculated that while these levels were low, there may be a cumulative protective effect on the brain from years of drinking this tap water. At least one previous study has suggested an association between lithium in tap water and suicide. That research on data collected from the 1980s also found a significantly lower rate of suicide in areas with relatively high lithium levels. The Japanese researchers called for further research in other countries but they stopped short of any suggestion that lithium be added to drinking water. The discussion around adding fluoride to water to protect dental health has proved controversial - criticised by some as mass involuntary medication. In an accompanying editorial, Professor Allan Young of Vancouver's Institute for Mental Health said "this intriguing data should provoke further research." (C)BBC

Keyword: Depression
Link ID: 12821 - Posted: 05.02.2009

By NICHOLAS WADE Locations for the Garden of Eden have been offered many times before, but seldom in the somewhat inhospitable borderland where Angola and Namibia meet. A new genetic survey of people in Africa, the largest of its kind, suggests, however, that the region in southwest Africa seems, on the present evidence, to be the origin of modern humans. The authors have also identified some 14 ancestral populations. The new data goes far toward equalizing the genetic picture of the world, given that most genetic information has come from European and Asian populations. But because it comes from Africa, the continent on which the human lineage evolved, it also sheds light on the origins of human life. “I think this is an enormously impressive piece of work,” said Alison Brooks, a specialist on African anthropology at George Washington University. The origin of a species is generally taken to be the place where its individuals show the greatest genetic diversity. For humans, when the new African data is combined with DNA information from the rest of the world, this spot lies on the coast of southwest Africa near the Kalahari Desert, the research team, led by Sarah A. Tishkoff of the University of Pennsylvania, said in this week’s issue of Science. Dr. Brooks, who spent many years in the area, said that it had some trees but that it also had deep sand and was not particularly garden-like. The area is a homeland of the Bushmen or San people, whose language is distinguished by its many click sounds. Copyright 2009 The New York Times Company

Keyword: Evolution
Link ID: 12820 - Posted: 06.24.2010

By Stephanie Pappas When hunger strikes, do you reach for celery or a candy bar? How well you stick to your diet could depend on the activity of a small region in your forebrain, according to a new study on self-control. The research could open doors to better understanding destructive behaviors such as overeating, drinking, and smoking. Behavioral researchers have long known that self-control is an important component of decision-making. But less is understood about the brain regions involved. Several areas in the forebrain show activity when a person makes tough choices, yet scientists disagree on how these regions work together. How, for example, does the brain weigh the short-term sugar rush of a chocolate bar against the long-term health benefits of a salad? Now, researchers from the California Institute of Technology in Pasadena say they have the answer. The scientists recruited 37 dieters who had been successful in losing or maintaining weight. The volunteers fasted for 3 hours and then entered a functional magnetic resonance imaging machine (fMRI), which measures brain activity. While inside, they viewed pictures of 50 different foods and rated each on a five-point scale for how healthy and tasty they considered it to be. The researchers then picked a food the dieter had rated neutral on both scales and asked the person to choose between that food and each of the 49 other options. Although all of the participants labeled themselves "dieters," about half threw self-control to the wind and went for the tastier treats, while the other half chose the healthier options. © 2009 American Association for the Advancement of Science.

Keyword: Obesity; Attention
Link ID: 12819 - Posted: 06.24.2010

By Virginia Morell Snowball, the dancing sulphur-crested cockatoo, is a big hit on YouTube--and now he's also a scientific sensation. Researchers have shown that the bird, who bobs his head and lifts his legs to the Backstreet Boys' song Everybody, is in fact listening to and following the beat. The findings--detailed in a pair of articles--challenge the notion that only humans have the neural wiring for dancing in time to music. "These are pathbreaking studies," says Bruno Repp, a cognitive psychologist at Haskins Laboratories in New Haven, Connecticut. Aniruddh Patel remembers the first time he saw Snowball on the Internet. A neurobiologist at the Neurosciences Institute in San Diego, California, Patel had argued in an earlier study that our talent for moving synchronously to a rhythmic beat is tied to our ability to learn and mimic sounds. "It seems to be a byproduct of a link between the auditory and motor parts of the brain," he says. That seemed to rule out most animals except humans and parrots. Nevertheless, Patel was stunned to see Snowball's video. "My jaw hit the floor," he says. To see if the cockatoo was actually in the groove and not simply trained, Patel visited Snowball at his Indiana home. He put the bird through the paces of a controlled experiment, speeding up and slowing down the music's tempo. Snowball wasn't fazed. "He adjusted the tempo of his dancing to stay synchronized to the beat," says Patel. To do so, he "must be monitoring the sounds" and changing his bobbing and kicking as the musical beat speeds up or slows down. The same neural abilities are required to imitate sounds, explains Patel, whose team reports its findings online today in Current Biology. © 2009 American Association for the Advancement of Science.

Keyword: Hearing
Link ID: 12818 - Posted: 06.24.2010

by Bob Holmes Remaining vigilant for five days and nights without a break would reduce any human to an incoherent, sleep-deprived daze – but dolphins can string together all-nighters without any detectable mental impairment. Sam Ridgway, a marine mammal biologist at the University of California, San Diego, and his colleagues trained captive dolphins to listen to a series of broadcast sounds. Most of the time, a short beep sounded every 30 seconds, but a few times per hour it was replaced by a slightly longer beep. When that happened, the dolphin had to press a lever for a food reward. Previously, Ridgway's team had shown that dolphins could stay alert and perform this task for up to 120 consecutive hours without any decline in accuracy. However, sleep-deprived humans show their fatigue most quickly in more complex mental tasks rather than such simple physical skills. To see if this is true of dolphins, too, Ridgway's team gave the dolphins a more complex task – in which they had to make different sounds in response to two different visual stimuli – at intervals during the 120-hour vigilance test. Here, too, the dolphins showed no sign of losing their sharpness as the days wore on. The dolphins' remarkable alertness may result from their ability to sleep on one side of the brain at a time. This unihemispheric sleep allows dolphins and other cetaceans to get the benefits of sleep even as they remain aware of their pod mates and predators – and, presumably, experimental sounds, says Ridgway. Journal reference: Journal of Experimental Biology (DOI: 10.1242/jeb.027896) © Copyright Reed Business Information Ltd

Keyword: Sleep; Evolution
Link ID: 12817 - Posted: 06.24.2010

It may take a combination of three molecules to kill brain cells in Parkinson's disease, researchers say. The three molecules — the neurotransmitter dopamine, a calcium channel, and a protein called alpha-synuclein — act together, Eugene Mosharov of Columbia University Medical Center in New York and his colleagues said in Wednesday's online issue of the journal Neuron. "Though the interactions among the three molecules are complex, the flip side is that we now see that there are many options available to rescue the cells," Mosharov said in a release. Symptoms of Parkinson's include uncontrollable tremors and difficulty in moving arms and legs. Scientists had suspected that three molecules were involved in killing neurons. The new findings suggest how it may happen. Using a new electrochemical approach to growing neurons in the lab, the researchers were able to measure dopamine released outside the cells. It's the location of dopamine that matters. Dopamine outside the cells, known as cytosolic dopamine, is toxic to neurons, the researchers found. If dopamine is confined inside cells, it's safe. Neurons lacking alpha-synuclein were resistant to the toxic damage. © CBC 2009

Keyword: Parkinsons
Link ID: 12816 - Posted: 06.24.2010

By Kaspar Mossman Michael Merzenich, neuroscientist at the University of California, San Francisco, is ruthless as he describes how my 37-year-old brain is going to turn to mush over the years to come. “You’re going to slowly decline in operating speed,” he says. “Your brain will become noisier and noisier in its processing.” And I will have more and more trouble figuring out exactly what it was I just heard or saw. The villain: age-related cognitive decline, which Merzenich says is a combination of physical changes and something called negative brain plasticity—the cerebral equivalent of what has happened to Arnold Schwarzenegger’s biceps. A way to combat negative brain plasticity is to train regularly using any of an increasingly wide range of software products designed expressly for the purpose, says Merzenich, who founded Posit Science, which makes one such package. Cognitive training is growing in popularity as baby boomers age. From 2005 to 2007 the U.S. brain fitness business increased from $100 million to $225 million, according to a report by SharpBrains, a market research company specializing in cognitive health. The growth was driven to a large extent by the success of Nintendo’s Brain Age [see my review of it and two other brain-training games in “Circuit Training”; Scientific American Mind, June/July 2006]. Research does confirm that regular brain exercise is beneficial to elderly people. ACTIVE, a nationwide clinical trial of 2,802 seniors that began in 1998, found that training in specific areas such as “processing speed” ­resulted in improvements that persisted at least five years. © 1996-2009 Scientific American Inc.

Keyword: Learning & Memory; Alzheimers
Link ID: 12815 - Posted: 06.24.2010

By CHRISTOPHER F. CHABRIS We are in the midst of an explosion of knowledge about how the human mind and brain work -- how memory comes in many different types, each stored in a different part of the brain; how our minds constantly process information outside our conscious awareness; how differences in brain function help to define differences in our personalities. A lot of this new knowledge raises provocative questions, not least about human nature. But as disgruntled students have been saying for ages: How are we ever going to use this stuff? Chemistry can boast of miracle drugs, and genetics has done wonders for our food supply and for medical diagnosis. What about psychology and neuroscience? Shouldn't research on learning and memory and thinking help us to learn, remember and think better? Daniel T. Willingham thinks that it should. In "Why Don't Students Like School?" he poses nine questions that a teacher might want to ask a cognitive scientist -- beginning with the question in the title -- and then answers each, citing empirical studies and suggesting ways for teachers to improve their practice accordingly. But Mr. Willingham's answers apply just as well outside the classroom. Corporate trainers, marketers and, not least, parents -- anyone who cares about how we learn -- should find his book valuable reading. So why don't students like school? According to Mr. Willingham, one major reason is that what school requires students to do -- think abstractly -- is in fact not something our brains are designed to be good at or to enjoy. When we confront a task that requires us to exert mental effort, it is critical that the task be just difficult enough to hold our interest but not so difficult that we give up in frustration. ©2009 Dow Jones & Company, Incc

Keyword: Learning & Memory
Link ID: 12814 - Posted: 06.24.2010

Eric Bland, Discovery News -- Lasers could one day cure, or at least aid in the search for drugs that treat diseases ranging from autism to schizophrenia, according to two new studies from the Massachusetts Institute of Technology and Stanford University and published in the online issue of the journal Nature. A blue laser shined into a live mouse brain triggered gamma waves, which are a kind of brain wave necessary for concentration and cognition that people with autism and schizophrenia often lack. "There are lots of theories about why [gamma wave oscillation] is impaired," said Li-Huei Tsai, a professor at MIT and a co-author on one of the Nature papers. "This is the first proof that a specific set of neurons are responsible for gamma waves." The specific neurons that trigger gamma waves are called fast-spiking interneurons. Connected to hundreds of other neurons, interneurons regulate which neurons fire and which neurons remain silent. The coordinated firing of these neurons creates a variety of brain waves, from ten waves per second of alpha waves to 40 waves per second of gamma waves. Scientists have known about gamma waves for decades. Using techniques that measure the brain's electrical activity, like EEG, scientists detect gamma waves when subjects concentrate during activities like test-taking. © 2009 Discovery Communications, LLC.

Keyword: Autism; Schizophrenia
Link ID: 12813 - Posted: 06.24.2010

by Ewen Callaway If you're going to challenge the Dalai Lama to a memory game, don't do it just after he's meditated. New research finds that meditation boosts visual memory, but only in the short term. The findings counter the claims of some monks who say that years of practicing a meditation technique that centres on creating an elaborate mental picture of deities can offer long-lasting improvements in visual memory and processing. "They claim they can do it all the time – they cannot," says Maria Kozhevnikov, a neuroscientist at George Mason University in Fairfax, Virginia, who travelled to several monasteries in Nepal to test the Buddhist monks' visual memory. Holy challenge In 2003, the Dalai Lama, who has a long-term interest in science and what he calls "the luminosity of being", attended a neuroscience conference at the Massachusetts Institute of Technology. There he challenged Kozhevnikov's then post-doctoral advisor, Stephen Kosslyn, to test the visual memory of Buddhist monks. Kosslyn and most other neuroscientists claimed that working memory was too short to maintain an image for more than a few seconds. He found no difference in visual memory between moderately practiced monks and non-meditators who came to his Harvard lab. The Dalai Lama suggested that Kosslyn test more experienced monks in Nepal, and Kozhevnikov took on the task while on sabbatical. © Copyright Reed Business Information Ltd

Keyword: Learning & Memory
Link ID: 12812 - Posted: 06.24.2010

Anna Salleh, ABC Science Online -- Females of an Australian species of lizard rely on testosterone for a most unusual method of keeping amorous males off their backs, researchers have found. Evolutionary ecologist Devi Stuart-Fox of the University of Melbourne and colleagues report their findings online ahead of print publication in the Journal of Comparative Physiology A. In most animals that use colorful displays for attraction, such as the peacock, it's usually the male that's flashy. But the female Lake Eyre dragon lizard (Ctenophorus maculosus) is an exception. She displays a bright orange belly and throat during parts of her breeding season, which researchers think is driven by the hormone testosterone. Interestingly, the color features prominently when the female wants to put off a male from copulating with her. Stuart-Fox and colleagues took a close look at a number of female lizards taken from Lake Eyre in South Australia and observed what happened when they were in the company of males. When Lake Eyre lizards copulate, the male bites the female's neck, climbs on top of her, wraps his tail around hers and inserts one of his two penises.

Keyword: Sexual Behavior
Link ID: 12811 - Posted: 04.30.2009

by Michael Bond ONE look at the effects of a bomb blast suggests that you'd have to be extremely lucky to emerge from one unscathed. If you were not burned by the explosion or blasted by shrapnel, the chances are you'd be hit by the shock wave. Travelling at several hundred metres per second, this causes massive fluctuations in air pressure which can knock you unconscious, rupture air-filled organs such as eardrums, lungs and bowels, and stretch and distort other major organs. Soldiers serving with coalition forces in Afghanistan and Iraq know only too well how devastating bombs can be. The effect of shrapnel on bodies - amputated limbs, broken bones, lacerated and burned flesh - is plain enough. Less obvious and harder to understand are the long-term effects of the shock wave on the brain. Weeks, months, or sometimes years after being concussed in an explosion, thousands of soldiers are reporting a mysterious clutch of problems. Dubbed post-concussion syndrome (PCS), symptoms include memory loss, dizziness, headaches, unexplained pains, nausea, disturbance of sleep, inability to concentrate and emotional problems. The US military and veterans' groups see PCS as a growing problem, and the US government is pouring millions of dollars into investigating it. Some doctors, however, particularly in the UK, believe that for many patients the symptoms ascribed to PCS are not caused by concussion at all, but by the shock and stress of wartime events. It may even be getting mixed up with post-traumatic stress disorder (PTSD), an acknowledged psychological reaction to disturbing events. "Some people are saying it's a hideous mistake and that we're talking up a problem," says Simon Wessely, a psychiatrist and director of the King's Centre for Military Health Research at King's College London. © Copyright Reed Business Information Ltd

Keyword: Stress
Link ID: 12810 - Posted: 06.24.2010

By Tina Hesman Saey Reading may be fundamental, but how the brain gives meaning to letters on a page has been fundamentally a mystery. Two new studies fill in some details on how the brains of proficient readers handle words. One of the studies, published in the April 30 Neuron, suggests that a visual-processing area of the brain recognizes common words as whole units. Another study, published online April 27 in PLoS ONE, reveals that the brain operates two fast parallel systems for reading, linking visual recognition of words to speech. Maximilian Riesenhuber, a neuroscientist at Georgetown University in Washington, D.C., wanted to know whether the brain reads words letter by letter or recognizes words as whole objects. He and his colleagues showed sets of real words or nonsense words to volunteers undergoing fMRI scans. The words differed in only one letter, such as “farm” and “form” and “soat” and “poat,” or were completely different, such as “farm” and “coat” or “poat” and “hime.” The researchers were particularly interested in what happens in the visual word form area, or VWFA, an area on the left side of the brain just behind the ear that is involved in recognizing words. Riesenhuber and his colleagues found that neurons in the VWFA respond strongly to changes in real words. Changing “farm” to “form,” for example, produced as profound a change in activity as changing “farm” to “coat,” the team reports in Neuron. The area responded incrementally to single-letter changes in made-up words. © Society for Science & the Public 2000 - 2009

Keyword: Language
Link ID: 12809 - Posted: 06.24.2010

by Linda Geddes The quest to understand the genetic underpinnings of autism has taken a big stride forward with the discovery of a genetic variant carried by more than two thirds of people with the disorder. Previous studies that have identified several genes that are implicated in autism, but Hakon Hakonarson of the Children's Hospital of Philadelphia, who led the new study, says they are extremely rare and account for a very small proportion of autism. "We have for the first time identified a common variant, present in over 65 per cent of autism cases." To identify the gene, Hakonarson and his colleagues screened DNA from more than 2500 people with autism and more than 7000 healthy controls, searching for common gene variants that were associated with the condition. The gene lies between two other genes called CAD 10 and CAD 9, which encode adhesion molecules that enable neurons to connect and communicate with one another – and CAD 10 is already known to be expressed in the very regions of the brain that appear to malfunction in people with autism. Because other, rarer genes associated with autism also encode cell adhesion molecules, researchers had previously speculated that a breakdown in neural connections during development might lie at the root of the condition. The current study provides the first genetic evidence that a similar problem could be implicated in a large number of cases, Hakonarson says. © Copyright Reed Business Information Ltd

Keyword: Autism; Genes & Behavior
Link ID: 12808 - Posted: 06.24.2010

A good night's sleep could reduce hyperactivity and bad behaviour among children, a Finnish study reports. It has been suggested that some children who lack sleep do not appear tired, but instead behave badly. Of the 280 examined in the Pediatrics study, those who slept for fewer than eight hours were the most hyperactive. Experts said adequate sleep could improve behaviour in healthy children and reduce symptoms of attention deficit hyperactivity disorder (ADHD). It is recognised that chronic sleep deprivation is a problem for many adults in Western countries and that it can have consequences for their health and daily life. The team behind this research said not enough was understood about the role of sleep in children's lives but it has been estimated that a third of US children do not get enough sleep. In this research, the team from the University of Helsinki and Finland's National Institute of Health and Welfare studied 280 healthy children aged seven or eight. They wanted to see if those healthy children who slept the least were the most likely to display the kind of symptoms associated with ADHD. None of the children studied had the attention disorder. Parents filled in questionnaires about their children's usual sleeping habits and then noted how long their children slept for over seven nights. The children also wore devices called actigraphs, which measure movement, to monitor how long they actually rested for. Parents' estimates of sleep duration were longer than the actigraph measurements, which the researchers say could be because they measured from bedtime or because they assumed their children were asleep when they were simply lying awake in bed or reading. The parents were also asked about their children's behaviour, using measures normally used to diagnose ADHD. The children whose average sleep duration as measured by actigraphs was shorter than 7.7 hours had a higher hyperactivity and impulsive behaviour score. They also had a higher ADHD symptom score overall. (C)BBC

Keyword: Sleep; ADHD
Link ID: 12807 - Posted: 04.28.2009

Children with attention deficit problems make bigger academic gains if they are taking stimulant medications compared to similar kids who aren’t receiving drug therapy, a new study shows. The findings, from a five year study of nearly 600 schoolchildren from across the country, are believed to be the first to offer an objective measure of the effect of drug therapy on a child’s long-term academic achievement. Earlier studies have shown that children who receive medication for attention-deficit hyperactivity disorder behave better in class and can complete more homework. But it hasn’t been clear whether treating A.D.H.D. results in any measurable improvement in long-term academic gains. The latest study, conducted by researchers at the University of California, Berkeley, and published in Pediatrics, tracked standardized math and reading scores among a nationally-representative sample of 600 children from kindergarten through the fifth grade, all of whom had been diagnosed with A.D.H.D. The researchers compared the scores of the students who were on A.D.H.D. medications with similarly diagnosed students who weren’t receiving drug therapy. In the study, taking A.D.H.D. medication was associated with gains in math scores that equated to about a fifth of a school year in extra learning. In reading, the gains were even greater, equating to progress of about a third of a school year. “I think the findings are important because this is the first time that we’ve had objective educational performance measures, to look at whether kids who are taking medications for A.D.H.D. compared to kids who are not, that actually show that they are doing better,” said Richard Scheffler, distinguished professor of health economics and public policy at the University of California, Berkeley’s School of Public Health. Copyright 2009 The New York Times Company

Keyword: ADHD
Link ID: 12806 - Posted: 06.24.2010

Fatty foods 'offer memory boost' A team at the University of California, Irvine discovered oleic acids from fats are converted into a memory-enhancing agent in the gut. They hope their work, published in Proceedings of the National Academy of Sciences, could offer a new way to treat memory-related problems. Drugs to mimic the action of the compound are in trials for controlling the dangerous fat triglyceride. Evidence shows high levels of oleoylethanolamide or OEA can reduce appetite, produce weight loss and lower blood cholesterol as well as triglyceride levels, making it an attractive candidate as a diet pill too. Dr Daniele Piomelli and his team discovered that OEA also causes memories to be laid down by activating memory-enhancing signals in the amygdala - the part of the brain involved with memories of emotional events. When they gave OEA to rats, it improved their memory retention in two different tests - running in a maze and avoiding an unpleasant experience. And when they blocked OEA with a drug, their performance on the tasks declined. Dr Piomelli said there was an evolutionary explanation for this role of OEA. He said: "By helping mammals remember where and when they have eaten a fatty meal, OEA's memory-enhancing activity seems to have been an important evolutionary tool for early humans and other animals. "Remembering the location and context of a fatty meal was probably an important survival mechanism for early humans." But he said this might not always be helpful. While OEA contributes to feelings of fullness after a meal, it could also engender long-term cravings for fatty foods that, when eaten in excess, can cause obesity. (C)BBC

Keyword: Learning & Memory; Obesity
Link ID: 12805 - Posted: 04.28.2009

Alison Abbott Nearly half of the neuroimaging studies published in prestige journals in 2008 contain unintentionally biased data that could distort their scientific conclusions, according to scientists at the National Institute of Mental Health in Bethesda, Maryland. Experts in the field contacted by Nature have been taken aback by the extent of the methodological errors getting through the supposedly strict peer-review systems of the journals in question. Nikolaus Kriegeskorte, Chris Baker and their colleagues analysed 134 functional magnetic resonance imaging (fMRI) studies published last year in five top journals — Nature, Science, Nature Neuroscience, Neuron and The Journal of Neuroscience. The survey, published in Nature Neuroscience on 26 April (N. Kriegeskorte, W. K. Simmons, P. S. F. Bellgowan and C. I. Baker Nature Neurosci. 12, 535–540; 2009), found that 57 of these papers included at least one so-called 'non-independent selective analysis'; another 20 may also have done so, but did not provide enough information to confirm suspicions. The non-independence of the analysis lies in using the same data to set up the conditions to test a hypothesis, then to confirm it. "We are not saying that the papers draw wrong conclusions, because in some cases the error will not have been critical," says Baker. "But in other cases we don't know, and this creates an ambiguity." © 2009 Nature Publishing Group

Keyword: Brain imaging
Link ID: 12804 - Posted: 06.24.2010