Experience in the early development of new neurons in specific brain regions affects their survival and activity in the adult brain, new research shows. How these new neurons store information about these experiences may explain how they can affect learning and memory in adults. A team of researchers headed by Fred Gage, PhD, of the Salk Institute, found that experience enhances the survival of new neurons in a brain area called the dentate gyrus, and that more of these new neurons were activated when exposed to the same experience later. This change in function may be a mechanism for long-term memory. The findings are published in the March 21 issue of The Journal of Neuroscience. "The results identify a critical period for experience-induced enhancement of new neuron survival in the hippocampus," says Elizabeth Gould, PhD, of Princeton University, who was not affiliated with the study. The hippocampus contains the dentate gyrus. After injecting mice with a chemical used to mark proliferating cells, the researchers exposed the animals to an "enriched cage" environment, containing tunnels, shelters, and a running wheel. After several weeks, the researchers again exposed the mice in the same enriched experience. They discovered that the enriched experience increased new neuron survival and that more new neurons were activated by re-exposure to the same environment. To determine if the increase in neuronal activity was due to having the same experience or if any new experience was sufficient to achieve this effect, the researchers exposed mice to the enriched cage first and then a water maze task. While both cases promoted new neuron survival, more new neurons were activated in mice that had repeated the same experience but not in those that were exposed to the different experience (the water maze).

Keyword: Neurogenesis; Learning & Memory
Link ID: 10124 - Posted: 03.23.2007

Scientists led by UCL (University College London) have induced dyscalculia in subjects without the maths learning difficulty for the first time. The study, which finds that the right parietal lobe is responsible for dyscalculia, potentially has implications for diagnosis and management through remedial teaching. Dyscalculia is just as prevalent in the population as dyslexia and attention deficit hyperactivity disorder – around 5% of the population is affected. However, dyscalculia has not been given the same attention as other disorders and the underlying brain dysfunction causing dyscalculia is still a mystery. It is hoped that this study will provide a better understanding of the condition and lead to better diagnosis and treatment. Dr Roi Cohen Kadosh, of the UCL Institute of Cognitive Neuroscience, said: “This is the first causal demonstration that the parietal lobe is the key to understanding developmental dyscalculia. Most people process numbers very easily – almost automatically – but people with dyscalculia do not. We wanted to find out what would happen when the areas relevant to maths learning in the right parietal lobes were effectively knocked out for several hundred milliseconds. We found that stimulation to this brain region during a maths test radically impacted on the subjects’ reaction time. “This provides strong evidence that dyscalculia is caused by malformations in the right parietal lobe and provides sold grounds for further study on the physical abnormalities present in dyscalculics’ brains."

Keyword: Miscellaneous
Link ID: 10123 - Posted: 06.24.2010

Scientists say they have developed a 3D scanner that can accurately determine if a person is truly obese. Currently, doctors gauge fatness with a calculation of body mass index (BMI). But BMI is flawed - people with lots of muscle are considered overweight. Instead of relying on weight and height measurements, as BMI does, the scan takes into account body shape and how much fat a person carries. Birmingham's Heartlands Hospital has been testing this Body Volume Index. One human guinea pig who has tested the BVI scanner is 19-year-old rower Ashley Granger. He is 6ft 2ins (1.88m) tall and according to his BMI of 28 is at the top end of the overweight category, borderline obese. His BVI scan correctly showed that he carries very little fat and that his weight is largely down to muscle. Fitness trainer Matt Roberts said: "Muscle weighs more than fat does. And you can hide away fat but be quite thin looking. So it's important that we don't just use BMI alone." (C)BBC

Keyword: Obesity
Link ID: 10122 - Posted: 03.23.2007

By Noah Shachtman The U.S. military is working on computers than can scan your mind and adapt to what you're thinking. Since 2000, Darpa, the Pentagon's blue-sky research arm, has spearheaded a far-flung, nearly $70 million effort to build prototype cockpits, missile control stations and infantry trainers that can sense what's occupying their operators' attention, and adjust how they present information, accordingly. Similar technologies are being employed to help intelligence analysts find targets easier by tapping their unconscious reactions. It's all part of a broader Darpa push to radically boost the performance of American troops. "Computers today, you have to learn how they work," says Navy Commander Dylan Schmorrow, who served as Darpa's first program manager for this Augmented Cognition project. He now works for the Office of Naval Research. "We want the computer to learn you, adapt to you." So much of what's done today in the military involves staring at a computer screen -- parsing an intelligence report, keeping track of fellow soldiers, flying a drone airplane -- that it can quickly lead to information overload. Schmorrow and other Augmented Cognition (AugCog) researchers think they can overcome this, though. The idea -- to grossly over-simplify -- is that people have more than one kind of working memory, and more than one kind of attention; there are separate slots in the mind for things written, things heard and things seen. © 2007 CondéNet Inc

Keyword: Attention; Brain imaging
Link ID: 10121 - Posted: 06.24.2010

The NIH National Institute of Neurological Disorders and Stroke (NINDS) today is launching a large-scale clinical trial to learn if the nutritional supplement can slow the progression of Parkinson's disease (PD). While creatine is not an approved therapy for PD or any other condition, it is widely thought to improve exercise performance. The potential benefit of creatine for PD was identified by Parkinson’s researchers through a new rapid method for screening potential compounds. The double-blind, placebo-controlled, phase III study is one of the largest PD clinical trials to date. It will enroll 1720 people with early-stage PD at 52 medical centers in the United States and Canada. "This study is an important step toward developing a therapy that could change the course of this devastating disease," says Elias A. Zerhouni, M.D., director of the NIH. "The goal is to improve the quality of life for people with Parkinson's for a longer period of time than is possible with existing therapies." Currently there is no treatment that has been shown to slow the progression of PD. The trial is the first large study in a series of NINDS-sponsored clinical trials called NET-PD (NIH Exploratory Trials in Parkinson's Disease). NINDS has organized this large network of sites to allow researchers to work with PD patients over a long period of time, with a goal of finding effective and lasting treatments. NET-PD builds on a developmental research process — from laboratory research to pilot studies in a select group of patients, to the definitive phase III trial of effectiveness in people with Parkinson’s disease.

Keyword: Parkinsons
Link ID: 10120 - Posted: 06.24.2010

Michael Hopkin British scientists asked by the government to rank the harm of different drugs of abuse today publish their results in the Lancet1. The new system, which puts alcohol and tobacco below heroin but above cannabis, is an attempt to provide a scientific — if still simplistic — way to compare the social and health tolls taken by recreational drugs. "The current drug classification system is rather arbitrary in terms of the way it assesses harm," says David Nutt of the University of Bristol, UK, and one of the team who devised the new system. Current British drug laws, he says, are shaped by political prejudice as much as by the actual threats posed by the substances. Recreational drugs pose various types of threat — from the possibility of an accidental overdose causing sudden death, to a parent's desire for alcohol pulling them away from their responsibilities at home. Comparing such physical and social harms, for both long-term and short-term effects, is very difficult. Nutt and his colleagues used a simple system to approach the problem. They set up three categories of threat — physical harm, dependence, and social harm — and divided each of these into three sub-categories (see 'The categories of harm'). They then asked experts - including psychiatrists specializing in addiction, members of police, forensic experts, chemists and doctors - to give up to 20 drugs a score out of three for each of the nine categories. The average scores for each of the three main categories of threat were then simply added together and averaged again to calculate an overall score out of three. ©2007 Nature Publishing Group

Keyword: Drug Abuse
Link ID: 10119 - Posted: 06.24.2010

Lucy Odling Smee Simply by inserting a piece of DNA that codes for a human eye pigment into the genome of a mouse, scientists have introduced a rainbow array of colour to the dull mix of yellows, blues and greys that normally make up a mouse's visual world. This suggests that the mammalian brain is very flexible and can interpret signals not normally encountered. It also hints that just a single genetic mutation could have added reds and greens to the visual palette of our ancestors tens of millions of years ago. Gerald Jacobs from the University of California in Santa Barbara and his colleagues have genetically engineered mice with a human pigment in their eye as well as the normal mouse pigments and shown that this does appear to give the mice the ability to see colours they could not see before. "The implications are astounding," says David Williams, an expert in vision at the University of Rochester in New York state. "It's stunning to think the rest of the nervous system in the mouse has developed to be able to process the new information." Most mammals have just two kinds of photopigment in their retinas: one is encoded in the X chromosome and the other in an autosomal (non-sex) chromosome. But many primates, including humans, have a third photopigment, encoded by a second gene on the X chromosome. This allows for a much broader appreciation of colour. ©2007 Nature Publishing Group

Keyword: Vision
Link ID: 10118 - Posted: 06.24.2010

Battling meningitis as a baby has a damaging effect on later academic achievement, a study suggests. Imperial College London found one in four teenagers who had meningitis in their first year failed to pass a single GSCE exam at grade C or above. Among comprehensive school pupils, meningitis survivors were twice as likely to fail to achieve the national standard of five grade C passes. The study appears in Archives of Disease in Childhood. It is essential that all cases of bacterial meningitis occurring during the first year of life are followed up fully It also found children who appeared to have escaped meningitis unscathed when assessed at age five did no better in their GCSE examinations than those with recognised disabilities. Meningitis is an inflammation of the brain lining - the meninges - which can cause serious disability or even death. The researchers compared the exam results of 461 students who survived meningitis as babies, with 289 students who had never developed the disease. They found 25% of the meningitis survivors failed to pass a single GSCE exam, compared with just 6.6% of the comparison group. Among comprehensive school attendees, 48% of meningitis survivors failed to achieve five grade C passes - the figure for the comparison group was 25%. (C)BBC

Keyword: Development of the Brain; Intelligence
Link ID: 10117 - Posted: 03.22.2007

BETHESDA, Md. – Researchers have identified a novel gene mutation that causes X-linked mental retardation for which there was no previously known molecular diagnosis, according to an article to be published electronically on Tuesday, March 20, 2007 in The American Journal of Human Genetics. Investigators F. Lucy Raymond (Cambridge Institute of Medical Research, University of Cambridge, Cambridge, UK) and Patrick S. Tarpey (Wellcome Trust Sanger Institute, Hixton, UK) describe the ZDHHC9 gene found in those with severe retardation as being mutated to the point of entirely losing function. "ZDHHC9 is a novel gene," explains Dr. Raymond. "This gene would not have been predicted to play a role in mental retardation based on the previous genetics work. It was found only because we were systematically looking at all the genes on the X chromosome irrespective of what they do." X-linked mental retardation is severe. Some patients require total care and may not have language ability. The condition runs in families and only affects the male offspring. So far only a few of these genes have been identified. Working through a large, international collaboration, the researchers collected genetic samples from 250 families in which at least two boys have mental retardation to help identify novel genes that cause X-linked mental retardation. The investigators systematically analyzed the X chromosome for gene mutations.

Keyword: Genes & Behavior; Intelligence
Link ID: 10116 - Posted: 06.24.2010

A quiet night's sleep is not an option for Derek Rogers or his wife - because he turns from a mild-mannered "Dr Jekyll" by day to a "Mr Hyde" by night. Mr Rogers, 70, from Bedford, has a rare sleep disorder which causes him to become violent when he sleep-walks. He has destroyed furniture, attacked his wife and injured himself during the night - but remembers nothing. Doctors at Papworth Hospital have found a drug which has successfully treated Mr Rogers' "unique" condition. Since he developed the condition in 1998, Mr Rogers has visited casualty up to three times a week. He has broken his nose, fractured his ribs and split his head open. South-African born Mr Rogers tried six different treatments before he was referred to the sleep clinic at Papworth Hospital in Cambridge. He said: "I am not violent - I do not swear or curse and I can't believe what I do at night." His wife Linda has had to sleep in a different room to avoid her husband lashing out. Doctors at Papworth decided to try a new £13,000 a year drug mix, which acts to break the circuit between the sleeping brain and muscles in the body. (C)BBC

Keyword: Sleep
Link ID: 10115 - Posted: 03.22.2007

John Whitfield Dogs wag their tails to the right when they see something they want to approach, and to the left when confronted with something they want to back away from, say researchers in Italy. The finding provides another example of how the right and left halves of the brain do different jobs in controlling emotions. Unfortunately, because dogs move about so much, the bias can only be detected using video analysis. It's not obvious enough for you to tell whether the next dog you encounter is going to lick your face or turn tail. "After discovering this, I look at every dog I meet, but my impression is that this is difficult to check outside the lab," says psychologist Giorgio Vallortigara of the University of Trieste. But it could be used in animal welfare, he suggests, to help gauge an animal's state of mind. Vallortigara and his colleagues tested 30 pet dogs of varying breeds, recruited through an obedience school at the University of Bari's veterinary faculty. Over a series of trials, they videoed each dog's response to being shown either their owner, a human stranger, a cat, or a Belgian shepherd malinois, a large dog breed similar to a German shepherd. ©2007 Nature Publishing Group

Keyword: Laterality
Link ID: 10114 - Posted: 06.24.2010

Kerri Smith A runaway train is speeding down the tracks towards five workmen. You and a stranger are standing on a bridge over the track. The only way to save the five is to push the stranger in front of the train to his death, and his body will stop it from reaching them. Do you push him? Most people answer that they could not personally push a stranger to his death, even though more lives would be saved than lost. But a new study published online in Nature finds that people with damage to a particular part of the frontal lobe reach the opposite — alarmingly utilitarian — conclusion1. Antonio Damasio at the University of Southern California in Los Angeles and his colleagues used a battery of dilemmas like this one to explore the role of emotion in moral decisions. Healthy subjects rejected most of the solutions that involved harming one person to save many lives, but the team found that people with damage to the ventromedial prefrontal cortex (VMPC), a brain area just behind the forehead, endorsed such decisions. These patients, whose brain damage resulted from stroke or the removal of a brain tumour, made perfectly normal decisions when the scenarios didn't have a moral component (is it all right to change a cake recipe if you don't like it?) or were asked to make less personal decisions (is it all right to push a heavy sculpture off a bridge to save the five workmen?). But when patients responded to more personal moral dilemmas, they were more than twice as likely as both normal controls and patients with brain damage that didn't include the VMPC to decide to harm one person — even their own child — to save more lives in the future. ©2007 Nature Publishing Group

Keyword: Emotions
Link ID: 10113 - Posted: 06.24.2010

Roxanne Khamsi Many patients suffering from severe depression "test positive" for post-traumatic stress disorder, regardless of whether or not they have actually experienced trauma, a new study reveals. Based on this finding, researchers say that psychiatrists need to identify more specific criteria for PTSD. Doing so, they suggest, will "save the diagnosis" from becoming too general and therefore misleading. Alexander Bodkin at Harvard's McLean Hospital in Belmont, Massachusetts, US, and colleagues recruited 101 patients with severe depression for their study. The participants answered questions about whether they had suffered symptoms of PTSD such as intrusive thoughts, emotional numbing, flashbacks and hopelessness. Two independent experts were then brought in to identify those subjects that had experienced a traumatic event, using standard tests issued by the American Psychiatric Association (APA). The experts were not told the patients' earlier reported symptoms. According to the APA's PTSD guidelines, trauma involves witnessing or experiencing "actual or threatened death or serious injury, or a threat to the physical integrity of oneself or others". The experience of trauma constitutes the primary criterion for PTSD. © Copyright Reed Business Information Ltd

Keyword: Depression; Stress
Link ID: 10112 - Posted: 06.24.2010

By LAURAN NEERGAARD WASHINGTON -- More than 5 million Americans are living with Alzheimer's disease, a 10 percent increase since the last Alzheimer's Association estimate five years ago _ and a count that supports the long-forecast dementia epidemic as the population grays. Age is the biggest risk factor, and the report to be released Tuesday shows the nation is on track for skyrocketing Alzheimer's once the baby boomers start turning 65 in 2011. Already, one in eight people 65 and older have the mind-destroying illness, and nearly one in two people over 85. Unless scientists discover a way to delay Alzheimer's brain attack, some 7.7 million people are expected to have the disease by 2030, the report says. By 2050, that toll could reach 16 million. Why? Ironically, in fighting heart disease, cancer and other diseases, "we're keeping people alive so they can live long enough to get Alzheimer's disease," explains association vice president Steve McConnell. Indeed, government figures released last year that show small drops in deaths from most of the nation's leading killers between 2000 and 2004 _ even as deaths attributed to Alzheimer's disease increased 33 percent. © 2007 The Associated Press

Keyword: Alzheimers
Link ID: 10111 - Posted: 06.24.2010

By Mary Carmichael, Newsweek - The stereotype of the "dumb jock" has never sounded right to Charles Hillman. A jock himself, he plays hockey four times a week, but when he isn't body-checking his opponents on the ice, he's giving his mind a comparable workout in his neuroscience and kinesiology lab at the University of Illinois. Nearly every semester in his classroom, he says, students on the women's cross-country team set the curve on his exams. So recently he started wondering if there was a vital and overlooked link between brawn and brains—if long hours at the gym could somehow build up not just muscles, but minds. With colleagues, he rounded up 259 Illinois third and fifth graders, measured their body-mass index and put them through classic PE routines: the "sit-and-reach," a brisk run and timed push-ups and sit-ups. Then he checked their physical abilities against their math and reading scores on a statewide standardized test. Sure enough, on the whole, the kids with the fittest bodies were the ones with the fittest brains, even when factors such as socioeconomic status were taken into account. Sports, Hillman concluded, might indeed be boosting the students' intellect—and also, as long as he didn't "take a puck to the head," his own. Hillman's study, which will be published later this year, isn't definitive enough to stand alone. But it doesn't have to: it's part of a recent and rapidly growing movement in science showing that exercise can make people smarter. Last week, in a landmark paper, researchers announced that they had coaxed the human brain into growing new nerve cells, a process that for decades had been thought impossible, simply by putting subjects on a three-month aerobic-workout regimen. Other scientists have found that vigorous exercise can cause older nerve cells to form dense, interconnected webs that make the brain run faster and more efficiently. And there are clues that physical activity can stave off the beginnings of Alzheimer's disease, ADHD and other cognitive disorders. No matter your age, it seems, a strong, active body is crucial for building a strong, active mind. © 2007 MSNBC.com

Keyword: Alzheimers
Link ID: 10110 - Posted: 06.24.2010

A rose by any other name would smell as sweet, but would the placebo effect work even better if it weren't being defamed by the slur that doubles as its name? This is a column that asks you to give the placebo effect a more pleasing moniker, but before you can do that you have to understand the various contexts for my plea. One is quite personal. I described in my last column how my elbow recently became painful. What followed was a visit to the doctor's office and a blissful injection of cortisone. But as I was starting to feel better I had a doubt: Was the relief due to real medicine or was I feeling merely the placebo effect? And what difference would that make? And what if painlessness were 20-per-cent placebo effect, 80-per-cent cortisone's healing power? And why did it come to be called the placebo effect in the first place? The last question is the easiest to answer. While there are ancient — think back to Socrates — references to the curative power of belief in a fictitious cure, placebo itself is derived from a translation into Latin of verse 9, Psalm 116 of the Bible. It says in English: "I will walk before the Lord in the land of the living." That becomes in Latin Placebo Domino in regione vivorum and the words were sung at funerals in the 13th century, not just by genuine mourners but by a coterie of fake mourners hoping to get some payment for their efforts. © CBC 2007

Keyword: Pain & Touch
Link ID: 10109 - Posted: 06.24.2010

When Craig Fox is offered an extended warranty for his consumer electronics, he tends to turn it down. He also turns down additional insurance coverage when he picks up a rental car. He's not being risky; he says he's simply taking a "risk-neutral" approach at life. Fox's research looks at how we handle risk, and he finds that many people are risk-averse, a theory that losses psychologically have more of an impact than gains when people make decisions. "I realize that if we're even a little risk-averse for every decision we make in our lives, in the grand scheme of things, we're extraordinarily risk-averse," Fox says, a behavioral decision theorist at the University of California, Los Angeles. "So for example, if I give you a 50-50 chance of gaining or losing money, most people will reject those gambles unless the gain side is much larger than the loss side," he says. Risk-aversion is a key part of prospect theory, a behavioral model that won Fox's mentor, Daniel Kahneman, the 2002 Nobel Prize in Economics. Prospect theory explains behavior in the lab and real world, Fox says. In one experiment, people ascribed a higher value to a mug once they perceived that it was theirs. The theory also helps to explain some of the economic forces that drive safer investments in the stock market. © ScienCentral, 2000-2007.

Keyword: Drug Abuse; Emotions
Link ID: 10108 - Posted: 06.24.2010

Roxanne Khamsi Mice with a gene mutation that disrupts their sleep cycles show signs of hyperactivity and addictive tendencies, a new study reveals. Researchers say that such "manic" behaviour displayed by the animals bolsters the theory that glitches in the body's internal clock can cause psychiatric illnesses such as bipolar disorder. Mice that received injections of DNA to compensate for the mutated gene regained regular sleep cycles and showed normal behaviour. This type of gene therapy will not work to treat people with bipolar disorder anytime soon, researchers stress, but they believe genetic experiments in rodents will reveal the potential targets for psychiatric drug treatments. Colleen McClung at the University of Texas Southwestern Medical Center in Dallas, US, and colleagues conducted experiments on mice with a mutation in their Clock gene. This gene normally activates other genes in the cell – with a certain regularity and on a daily basis. The human version is thought to be responsible for many of our circadian rhythms, including our wake/sleep cycle. Journal reference: Proceedings of the National Academy of Sciences (DOI: 10.1073/pnas.0609625104) © Copyright Reed Business Information Ltd

Keyword: Biological Rhythms; Schizophrenia
Link ID: 10107 - Posted: 06.24.2010

Researchers at the University of Illinois have found that adolescence is a time of remodeling in the prefrontal cortex, a brain structure dedicated to higher functions such as planning and social behaviors. The study of rats found that both males and females lose neurons in the ventral prefrontal cortex between adolescence and adulthood, with females losing about 13 percent more neurons in this brain region than males. This is the first study to demonstrate that the number of neurons in the prefrontal cortex decreases during adolescence. It is also the first to document sex differences in the number of neurons in the PFC. The study appears in the Feb. 9 issue of the journal Neuroscience. Earlier studies in humans have found gradual reductions in the volume of the prefrontal cortex from adolescence to adulthood, said psychology professor and principal investigator Janice M. Juraska. "But the finding that neurons are actually dying is completely new. This indicates that the brain reorganizes in a very fundamental way in adolescence." Juraska, graduate student Julie Markham and undergraduate student John Morris found that the number of neurons decreased in the ventral, but not dorsal, prefrontal cortex during adolescence. The number of glial cells, which surround and support the neurons, remained stable in the ventral PFC and increased in the dorsal PFC. These findings challenge current models of brain development by showing that some parts of the brain are still being organized well after puberty.

Keyword: Development of the Brain; Apoptosis
Link ID: 10106 - Posted: 03.21.2007

By ERIC NAGOURNEY Anyone who has tried to learn Chinese can attest to how hard it is to master the tones required to speak and understand it. And anyone who has tried to learn to play the violin or other instruments can report similar challenges. Now researchers have found that people with musical training have an easier time learning Chinese. Writing in the online edition of Nature Neuroscience, researchers from Northwestern University say that both skills draw on parts of the brain that help people detect changes in pitch. One of the study’s authors, Nina Kraus, said the findings suggested that studying music “actually tunes our sensory system.” This means that schools that want children to do well in languages should hesitate before cutting music programs, Dr. Kraus said. She said music training might also help children with language problems. Mandarin speakers have been shown to have a more complex encoding of pitch patterns in their brains than English speakers do. This is presumably because in Mandarin and other Asian languages, pitch plays a central role. A single-syllable word can have several meanings depending on how it is intoned. For this study, the researchers looked at 20 non-Chinese speaking volunteers, half with no musical background and half who had studied an instrument for at least six years. Copyright 2007 The New York Times Company

Keyword: Language; Hearing
Link ID: 10105 - Posted: 06.24.2010