DURHAM, N.C. -- Duke University Medical Center neurobiologists have pinpointed circuitry in the brains of monkeys that assesses the level of risk in a given action. Their findings -- gained from experiments in which they gave the monkeys a chance to gamble to receive juice rewards -- could give insights into why humans compulsively engage in risky behaviors, including gambling, unsafe sex, drug use and overeating. The researchers, Michael Platt, Ph.D., and Allison McCoy, published their findings in the advanced online version of Nature Neuroscience, posted August 14, 2005. The research was sponsored by the National Institutes of Health, the EJLB Foundation, and the Klingenstein Foundation. In their experiments, the researchers gave two male rhesus macaque monkeys chances to choose to look at either of two target lights on a screen. Looking at the "safe" target light yielded the same fruit juice reward each time. However, looking at the "risky" target light might yield a larger or smaller juice reward. The average juice reward delivered by looking at either target was the same. To their surprise, the monkeys overwhelmingly preferred to gamble by looking at the risky target. This preference held, regardless of whether the scientists made the risky target reward more variable, or whether the monkeys had received more or less fruit juice during the course of the day. © 2001-2005 Duke University Medical Center

Keyword: Emotions; Drug Abuse
Link ID: 7780 - Posted: 06.24.2010

Jennifer Wild The American Psychological Association (APA) has adopted a resolution to reduce violence in children's interactive media. This follows an in-depth review confirming that violent video games can make kids aggressive in the short-term, they say. The long-term effects are still unknown. Some researchers say that playing 'shoot 'em up' video games is directly linked to kids' aggressive behaviour in the real world. Others say the games are a healthy outlet. Many say the research is so mixed that the jury is still out. That's in part because researchers have used different measures of aggressive behaviour, and different definitions of what makes for a violent game. Some have looked at physiological arousal, such as an increased heart rate, whereas others have measured violent thoughts. Not many studies have looked at violent acts. To clarify where the field stands, Kevin Kieffer and Jessica Nicoll of Saint Leo University in Saint Leo, Florida, conducted an extensive review of 17 studies conducted over 20 years. They presented their results at the 113th APA conference in Washington DC on Friday 19 August. According to their review, there's a strong link between these games and how children and adolescents behave - at least in the short term. ©2005 Nature Publishing Group

Keyword: Aggression
Link ID: 7779 - Posted: 06.24.2010

Humans are not the only conformists in the animal kingdom. New research shows that chimpanzees also tend to imitate their peers, suggesting that the human penchant for follow-the-leader may be more deeply rooted than thought. Chimpanzees have behavioural traditions that vary between groups in the wild but, so far, direct experimental evidence of how these traditions are spread and maintained has been lacking. So Andrew Whiten of St Andrews University, UK, led a team that sought to show a chimpanzee proclivity for cultural conformity in a population of captive animals. Whiten demonstrated cultural learning in chimps by introducing two different tool-use techniques to two separate groups of captive chimps at the Yerkes National Primate Research Center in Atlanta, Georgia, US. The team taught two female chimps how to get food out of a complicated apparatus using a stick. One learned to poke a barrier with the stick, and the other to lift the barrier with the stick. Then the chimps’ groups got to watch the new experts use their skills. When the rest of the groups were allowed to try their own hand at freeing the food, they followed the lead of their own expert chimp – the poker’s group preferred to poke and the lifter’s group tended to lift. © Copyright Reed Business Information Ltd.

Keyword: Evolution
Link ID: 7778 - Posted: 06.24.2010

FIONA MACGREGOR EATING just two portions of fish a week during childhood could double the risk of dying from a stroke in later life, according to a new report. The findings come after scientists reviewed the cause of death for over 4,000 people who had been part of the Boyd Orr survey on family diet and health carried out across Britain during the late 1930s. The academics from Bristol University said they could find no correlation between early eating habits and other causes of mortality, but they identified clear links between childhood diet and strokes. Dr Andy Ness of the Unit of Paediatric and Perinatal Epidemiology at the University of Bristol said: "We found that children who ate the most vegetables had a reduced risk of stroke, which ties in with the recognised benefits of vegetables, but somewhat surprisingly we found an association between fish and strokes. "There was a twofold increase in risk between those whose diet contained the most fish, at least two or three portions a week, and those who ate little or no fish." He added that the study had not aimed to identify why eating fish could lead to strokes, but called for further research. "The whole issue of fish being healthy is complicated. I would not stop my own children eating fish because of these findings, but I would probably avoid giving them fish every day." ©2005 Scotsman.com

Keyword: Stroke
Link ID: 7777 - Posted: 06.24.2010

Simon Wessely, M.D. At least until the failed attacks of July 21, the gut-wrenching shock of the July 7 suicide bombings in London had been starting to dissipate, and the nonstop news coverage was slowing. Gradually, Londoners were beginning to get on with their lives. Three days after the bombings, I joined the crowds celebrating the 60th anniversary of the end of the Second World War. The sun shone, and the Mall was full of old, proud men, wearing polished medals and fading berets. A military band gave a surprisingly good impersonation of the Glenn Miller Orchestra, and a Lancaster bomber accompanied by two Spitfires flew overhead, dropping poppies on us. The following day, England played Australia at cricket, and all seemed normal — including the resounding English defeat. True, there were more police than usual and we now had to enter the grounds by way of metal detectors, but the rituals of a London summer had returned. But what about those for whom life as usual is not going to go on? Those whose lives have been shattered by bereavement and those whose bodies were shattered by the blasts of terrorist bombs? As one emergency worker told the BBC after leaving the scene of the bombing at King's Cross station, "I don't know what heaven looks like, but I now have a good idea of hell." Many of the survivors and the bereaved are suffering intense mental anguish, an anguish that is painful for the rest of us even to witness. copyrighted © 2005 Massachusetts Medical Society.

Keyword: Stress
Link ID: 7776 - Posted: 06.24.2010

SNOWBIRD, UTAH--When it comes to which boys they'd like to date, teenage girls aren't the only ones who tend to copy each other's choices. Nature is full of species behaving like adolescent humans, and new research shows that the tendency to copy may be a heritable trait, at least in guppies. Humans and other brainy mammals often teach their young to mimic the behavior of others. Young chimps, for example, have been observed intently watching as their elders show them how to crack open nuts using rocks. Such lessons ensure that certain behaviors will be passed on to the next generation. But in shorter lived, less social animals such as fish, there aren't many teachable moments. Yet in some species, generation after generation, animals still seem to copy each other's behaviors, leaving scientists to wonder if the copying habit itself can be inherited. To test the idea, biologist Lee Dugatkin of the University of Louisville in Kentucky examined female guppies, which mimic the mate choices of their peers. After a group of female fish gave birth, Dugatkin watched the moms to see how likely they were to copy another female's mate choice. Each mom was put in a tank alone with two males in adjacent tanks on either side. Another female was placed in a tank next to one of the males, and the mom was able to watch the courtship unfold. The courting female was then removed, leaving the mom alone to make a selection. If she spent more of her time near the male "chosen" by the other female, she was a considered a copier. About 85% of the females proved to be copiers, Dugatkin found. Copyright © 2005 by the American Association for the Advancement of Science.

Keyword: Sexual Behavior; Genes & Behavior
Link ID: 7775 - Posted: 06.24.2010

By Melanie Moran If your partner seems to be ignoring you after a flash of nudity on the television screen, it might not be his or her fault: A new psychological study finds that when people are shown violent or erotic images they frequently fail to process what they see immediately afterwards. Two studies that explore this effect, called attentional rubbernecking, were conducted by Vanderbilt University psychologist David Zald and Yale University researchers Steven Most, Marvin Chun and David Widders. The results are described in the August issue of the journal Psychonomic Bulletin and Review. “We observed that people fail to detect visual images that appeared one-fifth of a second after emotional images, whereas they can detect those images with little problem after viewing neutral images,” says Zald, assistant professor of psychology and member of the Vanderbilt Kennedy Center for Research on Human Development. Anyone who has ever slowed down to look at an accident as they are driving by – or has been stuck behind someone who has – is familiar with the “rubbernecking” effect. Even though we know we need to keep our eyes on the road, our emotions of concern, fear and curiosity cause us to stare out the window at the accident and slow to a crawl as we drive by. © 2000-2005 Vanderbilt University,

Keyword: Vision; Emotions
Link ID: 7774 - Posted: 06.24.2010

A new nasal vaccine for Alzheimer’s disease has cleared plaques from the brains of affected mice and will be tested in humans in 2006. Most previous attempts to produce a therapeutic vaccine have involved antibodies against beta amyloid, a naturally-occurring protein which is widely considered to cause the disease. In Alzheimer’s patients, beta amyloid forms plaques that seem to destroy neurons. But the antibody approach ran into problems three years ago, when a promising vaccine trial was halted after 15 of 360 volunteers developed swelling in the brain. Now Howard Weiner, at Brigham and Women’s Hospital in Boston, US, and his colleagues have tried a new strategy. Weiner was intrigued by the fact that brain inflammation in the earlier trial coincided with exceptional clearance of beta amyloid. He did some experiments and found that mice with Alzheimer’s treated to develop multiple sclerosis-like brain inflammation also cleared the beta amyloid from their brains. “Sometimes inflammation is good,” he says. His team discovered that in inducing inflammation they were activating cells in the brain known as microglia, whose job it is to ingest unwanted material. In this case, the microglia were ingesting the beta amyloid. Interestingly, in mice without beta amyloid plaques, no activation took place. © Copyright Reed Business Information Ltd.

Keyword: Alzheimers
Link ID: 7773 - Posted: 06.24.2010

New research published in the August 2005 issue of the American Journal of Psychiatry indicates that methamphetamine abuse and HIV infection cause significant alterations in the size of certain brain structures, and in both cases the changes may be associated with impaired cognitive functions, such as difficulties in learning new information, solving problems, maintaining attention and quickly processing information. Co-occurring methamphetamine abuse and HIV infection appears to result in greater impairment than each condition alone. "Methamphetamine abuse is linked with HIV, hepatitis C, and other sexually transmitted diseases, not only by the use of contaminated injection equipment, but also due to increased risky sexual behaviors," says Dr. Nora D. Volkow, director of the National Institute on Drug Abuse (NIDA), National Institutes of Health, which helped support the research. "These findings show that methamphetamine abuse and HIV infection each cause significant changes in the volume of brain gray matter structures and cognitive function." Scientists led by Dr. Terry Jernigan of the HIV Neurobehavioral Research Center of the University of California-San Diego conducted brain scans to analyze structural volume changes in 103 adults divided among four populations: methamphetamine abusers who were HIV-positive; methamphetamine abusers who were HIV-negative; nonabusers who were HIV-positive; and nonabusers who were HIV-negative. They also assessed the ability to think and reason using a detailed battery of tests that examined speed of information processing, attention/working memory, learning and delayed recall, abstraction/executive functioning, verbal fluency, and motor functioning.

Keyword: Drug Abuse
Link ID: 7772 - Posted: 08.12.2005

Scientists have discovered why it is that some people are chronic snorers. By carrying out head and neck scans of snorers and non-snorers, the Slovenia team found it was down to the shape of the throat. Snorers have narrower throats and the smaller the opening is, the loader the snore. Contrary to popular opinion, nasal blockages do not cause snoring though they may "amplify the loudness", the researchers told Chest journal. Dr Igor Fajdiga and his team studied 40 volunteers - 14 were non-snorers, 13 were moderately loud snorers and 13 were loud snorers, according to their spouses. How loudly people snored was directly related to the extent that their throat narrowed when they inhaled during their sleep - the narrower the throat, the bigger the snore. A culprit was the soft palate, which is the soft tissue at the back of the roof of the mouth. The snorers' soft palates were much bigger than those of non-snorers, meaning it blocked smooth airflow. Turbulent airflow is what creates the noise. When we are awake we have enough muscle tone to keep the airways open. However, when we are asleep we lose this tone. Being older and overweight can make the problem worse. (C)BBC

Keyword: Sleep
Link ID: 7771 - Posted: 08.11.2005

Pig brain cells wrapped in a seaweed derivative could be implanted into human brains by next year to treat Huntington's disease, if approved. Researchers at New Zealand's Living Cell Technologies in Auckland have already had good results in monkeys. They told New Scientist they were seeking approval to do the same in humans in the US. The Food and Drugs Administration has already approved trials with animal tissue for Parkinson's disease. However, there is concern that using animal cells in humans could spread infections from animals to humans. Huntington's Disease is an inherited condition caused by a single faulty gene and affects one in 100,000 people. Although present from birth, symptoms normally appear when the person is between 30 and 50. Cells start to die in an area of the brain which helps control the movement of the body's muscles. Patients experience gradually worsening twitches, loss of muscle control, and memory loss and eventually die from the condition. In an attempt to minimise this damage in primates, the New Zealand team used pig brain cells taken from the lining of a brain structure known as the choroid plexus. These cells have a nurturing role, mopping up toxins and secreting a range of chemicals that are reduced in Huntington's and are essential for brain cell function. (C)BBC

Keyword: Huntingtons
Link ID: 7770 - Posted: 08.11.2005

A guessing game that lets players idle away a few minutes online could also teach computers how to recognise the world around them. The game, called Peekaboom, was devised by researchers at Carnegie Mellon University in the US. It harnesses the brain power of online players to train a set of powerful vision recognition algorithms. This could eventually enable computers to recognise images in a similar way to humans - by focusing on the most relevant features. After signing up, a player is asked to slowly reveal parts of an image, chosen at random from the web - with an associated word describing it - to a second player. Player 2, in turn, must identify the whole image as quickly as possible. Player 1 can also tell their partner how "warm" or "cold" they are with each guess, or “peek”. The theory goes that Player 1 will choose to reveal the key features of the image first – those aspects that they consider best represents the whole. If the image was of a pig, for example, they might chose to reveal its distinctive snout to Player 2 first. "Intuitively, data collected from the game yields the portions of the image pertaining to the word," says developer Luis von Ahn. The approach could be used almost immediately to create search engines with a better knack for identifying images based on keywords entered into a search field. © Copyright Reed Business Information Ltd.

Keyword: Vision
Link ID: 7769 - Posted: 06.24.2010

Our eyes need light to work, but a body of research seems to suggest that too much of the wrong kind of light can lead to diseases like age-related macular degeneration. So as you head out to the beach with your sunglasses, keep in mind that they may not be protecting you from all of the damaging rays of the sun. It's well known that ultraviolet or UV light, which we can't see, can damage both skin and eye cells. But vision researchers are uncovering links between disease and some light that we can see. Now there's more evidence that blue light (400 – 500nm) can damage our eyes, with people who have had cataracts removed being particularly vulnerable. "Blue light is the most energetic portion of the visible light spectrum," says ophthalmologist Bernard Godley, of the Retina Foundation of the Southwest in Dallas. "It's less energetic than UV radiation but it also has the ability to penetrate into tissue and cause cellular damage." Godley, working with an international team of researchers, has shown that chronic exposure to blue light damages retina cells in the lab — the same cells involved in age-related macular degeneration (AMD), the leading cause of blindness untreatable vision loss and legal blindness in the U.S. for people over the age of 60. © ScienCentral, 2000-2005

Keyword: Vision
Link ID: 7768 - Posted: 06.24.2010

Bethesda, MD – A new study indicates that mutant Cu/Zn superoxide dismutase (SOD1) enzymes that are associated with an inherited form of Lou Gehrig's disease cause the protein to become sticky in tissues. Partial unfolding of the mutant protein can expose hydrophobic residues that may promote abnormal interactions with other proteins or membranes in the cell. The research appears as the "Paper of the Week" in the August 19 issue of the Journal of Biological Chemistry, an American Society for Biochemistry and Molecular Biology journal. Over 5,600 people in the U.S. are diagnosed with amyotrophic lateral sclerosis (ALS) or Lou Gehrig's disease each year. About 30,000 Americans have the disease at any given time, and 10% of cases are inherited. "Amyotrophic lateral sclerosis is a neurodegenerative disorder in which neurons of the motor pathways in the brain and spinal cord die," explains Dr. Lawrence J. Hayward of the University of Massachusetts Medical School. "It typically strikes during middle age, and although it may start with only mild weakness, the symptoms can spread insidiously over months to impair mobility, speech and swallowing, and ultimately the muscles required for respiration." Despite the prevalence of ALS, the biological mechanisms that kill the motor neurons in most patients are incompletely understood. However, for a fraction of inherited ALS patients, mutations in the gene for SOD1 cause the disease by creating a toxic enzyme. Evidence suggests that misfolding or partial unfolding of mutant SOD1 proteins in these patients might be key to the toxicity.

Keyword: ALS-Lou Gehrig's Disease
Link ID: 7767 - Posted: 06.24.2010

Researchers at the University of Alberta have isolated a rare condition that prevents some children from recognizing a face they have seen before. They believe this conditions continues into adulthood. "We believe this has never been discovered before," said Carmen Rasmussen, a doctoral student in the U of A Department of Psychology. "And now we hope to be able to better diagnose people with this condition and develop interventions to help them." Rasmussen and her colleague, Dr. Glennis Liddell of the Glenrose Rehabilitation Hospital, studied 14 children with Nonverbal Learning Disability (NLD), a condition that makes it difficult to process nonverbal information. Children with NLD generally do well on most elements of aptitude tests except for those that involve visual spatial processing, such as recognizing and working with shapes. "It can be difficult to recognize someone with NLD because sometimes the symptoms are not always obvious," Rasmussen explained.

Keyword: Autism; Development of the Brain
Link ID: 7766 - Posted: 08.11.2005

A gene that helps fruit flies develop alcohol tolerance has been found – and named “hangover”. The gene also controls the flies’ response to stress, and the researchers say that a similar pathway linking alcohol tolerance and stress probably functions in humans. The findings may explain why people who have been in a stressful situation often have a blunted response to alcohol and may drink more to feel inebriated, experts say, putting them at greater risk of becoming addicted. Ulrike Heberlein at the University of California at San Francisco, US, and Henrike Scholz from the University of Würzburg in Germany, exposed fruit flies to ethanol vapour. Intoxicated fruit flies show similar behaviour to tipsy humans: they lack coordination and postural control and then fall asleep. It took the flies an average of 20 minutes to recover following their exposure. After four hours on the wagon, the same Drosophila were again exposed to alcohol. By now, they had developed a tolerance to alcohol and so needed more to reach the same drunkenness, and took longer to “dry out” - 28 minutes. But flies with a defective form of the hangover gene still took 20 minutes to recover from inebriation time after time - never building up a tolerance. The researchers then investigated how the gene was involved in stress responses since, in humans at least, the alcohol and stress responses appear to be linked. © Copyright Reed Business Information Ltd.

Keyword: Drug Abuse; Genes & Behavior
Link ID: 7765 - Posted: 06.24.2010

RESTON, Va.— The role of the brain’s opioid receptor system—or endorphin system—may hold the key to understanding and treating bulimia nervosa, according to research reported in the Society of Nuclear Medicine’s August issue of the Journal of Nuclear Medicine. "Involvement of the opioid system may explain the addictive quality of this behavioral disorder," said Angela Guarda, M.D., assistant professor of psychiatry at Johns Hopkins School of Medicine in Baltimore, Md. The first imaging study to implicate the opioid system in bulimia nervosa shows differences in women with bulimia compared to healthy women, added J. James Frost, M.D., Ph.D., professor of radiology and neuroscience at Johns Hopkins and co-author of "Regional ì-Opioid Receptor Binding in Insular Cortex Is Decreased in Bulimia Nervosa and Correlates Inversely With Fasting Behavior." In the study, eight women with bulimia were compared to healthy women of the same age and weight. Their brains were scanned using positron emission tomography (PET) after injection with the short-acting radioactive compound carfentanil, which binds to mu-opioid receptors in the brain, explained Frost. PET is a powerful medical imaging procedure that noninvasively uses special imaging systems and radioactive tracers to produce pictures of the function and metabolism of the cells in the body. He noted, "We found that mu-opioid receptor binding in bulimic women was lower than in healthy women in the left insular cortex. The insula is involved in processing taste, as well as the anticipation and reward of eating, and has been implicated in studies of other driven behavioral disorders, including drug addiction and gambling.” Copyright © 2005 SNM

Keyword: Anorexia & Bulimia; Drug Abuse
Link ID: 7764 - Posted: 06.24.2010

The figure is famous: a deceptively simple line drawing that at first glance resembles a vase and, at the next, a pair of human faces in profile. When you look at this figure, your brain must rapidly decide what the various lines denote. Are they the outlines of the vase or the borders of two faces? How does your brain decide? It does so in a fraction of a second via special nerve circuits in the brain's visual center that automatically organize information into a "whole" even as an individual's gaze and attention are focused on only one part, according to Johns Hopkins researchers writing in a recent issue of the journal Neuron. "Our paper answers the century-old question of the basis of subconscious processes in visual perception, specifically, the phenomenon of figure-ground organization," said Rudiger von der Heydt, a professor in the Zanvyl Krieger Mind-Brain Institute. "Early in the 20th century, the Gestalt psychologists postulated the existence of mechanisms that process visual information automatically and independently of what we know, think or expect. Since then, there has always been the question as to whether these mechanisms actually exist. They do. Our work suggests that the system continuously organizes the whole scene, even though we usually are attending only to a small part of it."

Keyword: Vision
Link ID: 7763 - Posted: 08.10.2005

AFP — Practicing the piano as a young child gives the human brain a musical capacity that is difficult to acquire later in life, Swedish scientists found in a study. It is well-known that most of the world's great pianists were already practicing their scales and arpeggios while still under 10 years old, and the study, published in the Nature Neuroscience journal, shows that this is no coincidence. Childhood is the best time in life to boost the brain's so-called white matter, according to the study, and boost the pyramidal tract, which is a major pathway of the central nervous system, transmitting signals between the brain and the pianist's fingers. Copyright © 2005 Discovery Communications Inc.

Keyword: Learning & Memory; Development of the Brain
Link ID: 7762 - Posted: 06.24.2010

Alison Abbott Regular exercise keeps us fit. But not everyone is born equal: a few people get little benefit from physical activity because their genetic makeup doesn't allow it. Research now shows that the same holds true for the elderly, where the stakes are much higher. A third of adults over 70 in the US are unable to walk for half a kilometre without difficulty, or to climb up ten steps without having to stop for a rest. Such people are four times more likely to end up in a nursing home, and three times likelier to die before those who are fitter. To find out if there is a genetic component in who stays fittest the longest, Stephen Kritchevsky at Wake Forest University in Winston-Salem, North Carolina and his colleagues conducted a four-year study of 3,000 American adults in their seventies. The team examined participants every six months, and asked them about their mobility and how much exercise they took. At the end, they were surprised by how big a role genetics appears to play in keeping the elderly on their feet. ©2005 Nature Publishing Group

Keyword: Genes & Behavior
Link ID: 7761 - Posted: 06.24.2010