An international team of researchers has identified the role of a gene which may explain why some people overeat and become obese. Their research, published today in Public Library of Science Biology, shows that the gene GAD2 has an appetite stimulating role, and that one form of the gene is strongly associated with obese people. While the researchers recognise that obesity is a result of the interactions of many genes and environmental factors, this is one of the first genes to be strongly touted as a candidate 'gene for obesity'. GAD2, which sits on chromosome 10, acts by speeding up production of a neurotransmitter in the brain called GABA, or gamma-amino butyric acid. When GABA interacts with another molecule named neuropeptide Y in a specific area of the brain - the paraventricular nucleus of the hypothalamus - we are stimulated to eat.

Keyword: Obesity
Link ID: 4475 - Posted: 11.03.2003

Overweight kids more likely to have behavior problems, national data show ANN ARBOR, MI - In a study that points to the importance of considering both mind and body in children's health, researchers report today that they have found a clear link between childhood obesity and behavior problems. Results published today in the journal Pediatrics show that children who have significant behavior problems, as described by their parents, are nearly three times as likely to be overweight as other children. In addition, children with behavior problems are as much as five times more likely to become overweight later. The study, done by a University of Michigan behavioral pediatrician and her former colleagues at Boston University, is based on national data from an intensive long-term survey of mothers and children conducted by the U.S. Department of Labor.

Keyword: Obesity
Link ID: 4474 - Posted: 11.03.2003

Spatially, functional magnetic resonance imaging is the gold standard, but poor temporal resolution has researchers looking for something better | By Leslie Pray According to legend, functional neuroimaging can trace its roots to the stroke of noon on a day in the late 19th century, when Italian physiologist Angelo Mosso observed a sudden increase in brain pulsation in his test subject, Bertino the peasant. Using an elaborate contraption, Mosso had been measuring the pulsations coming from a soft spot in Bertino's skull, the result of a head injury. Intrigued by the sudden pulsing, Mosso asked Bertino if the chiming of the local church bell had reminded him of his forgotten midday prayers. When Bertino said yes, his brain pulsated again. Then Mosso asked Bertino to multiply 8 by 12. Again, Bertino's brain pulsated. Thus was borne the notion that blood flow in the brain is related to cognition. That notion remains the basis of what some neuroscientists consider the most powerful in vivo brain imaging technology in use today, functional magnetic resonance imaging (fMRI). Since its emergence in 1992, fMRI has dominated the field of human brain mapping and has been featured in thousands of published papers--nearly an order of magnitude more than for any other functional imaging technique. For noninvasive whole-brain coverage in humans, fMRI's spatial resolution cannot be beat. And, unlike its historical predecessor, positron emission tomography, fMRI does not depend on dangerous ionizing radiation. Martin Lauritzen, professor of clinical neurophysiology at Denmark's Glostrup Hospital and the University of Copenhagen, says, "In a way, I think the fMRI is a perfect machine." But there are things that even a perfect instrument cannot do, such as record neuronal events in real time. More profoundly, the technique is limited by interpretational challenges; handling the enormous amount of data that even a single scan produces requires statistical skill, both to uncover deeper truths and to prevent erroneous conclusions. ©2003, The Scientist Inc.

Keyword: Brain imaging
Link ID: 4473 - Posted: 06.24.2010

Functional MRI offers a compelling neurological view, but of what? | By Mike May For centuries, philosophers and biologists alike dreamed of watching the brain operate to see its active response to sensations, actions, or even thoughts. In some ways, functional magnetic resonance imaging (fMRI) provides such a view. This technology essentially measures blood flow to areas of the brain, and presumably neural activity, in real time. The technique could help researchers specifically map the brain. The visual cortex, for example, appears to light up when a subject sees something. Still, scientists remain unsure about exactly what the signal, the flashing spots on an fMRI screen, actually mean. Indeed, neuroscientists debate what fMRI measures and how it can best be used clinically. Paul Matthews of the University of Oxford calls it "perhaps the single most important general technique in cognitive neuroscience." But, he cautions, "It is being widely used with relatively little understanding of its fundamental basis." ©2003, The Scientist Inc.

Keyword: Brain imaging
Link ID: 4472 - Posted: 06.24.2010

Gauging the effects of alcohol and nicotine on adolescent brains | By Harvey Black It seems that the adolescent brain may be particularly vulnerable to the effects of nicotine and alcohol. At a recent conference where researchers discussed published and unpublished work, studies showed that alcohol's impact on a variety of brain activities appears more severe in adolescent rats. Similarly, though results don't always agree, the adolescent brain also appears to be extremely sensitive to the effects of nicotine. Adolescent drinking in the United States exacts an enormous societal cost -- $53 billion (US) annually for such things as drunk driving accidents and violent crimes--according to a new study by the National Research Council and the Institute of Medicine.1 Thirty percent of US high school seniors "are drinking heavily, at least once a month," the report states, and nearly 70% of UK adolescents said they did likewise three times in the previous month, according to the report. Discussing as yet unpublished research, H. Scott Swartzwelder, neuropsychologist at Duke University, Durham, NC, said that the neurotransmitter gamma aminobutyric acid was more resistant to alcohol's effects in hippocampal slices from adolescent rats than from those in adult rats. GABA's release induces sedation, Swartzwelder explained. While these findings have not been replicated in humans, they have clear implications for adolescents. He discussed the results at a New York Academy of Sciences conference in September. ©2003, The Scientist Inc.

Keyword: Drug Abuse; Development of the Brain
Link ID: 4471 - Posted: 06.24.2010

Investigators seek the tick and tock of the brain's clock | By Jack Lucentini British novelist Aldous Huxley in a bid to study perception supposedly taped his conversations after swallowing the hallucinogenic drug mescaline. During one such chat, a researcher asked him to describe how time felt. "There seems to be plenty of it," was all Huxley could offer.1 Silly as that sounds, few have done much better in explaining time or its sensation. Yet scientists are taking the first stabs at answering at least one part of the question: how the brain perceives time. For example, a University of Washington study is the first to document how neurons in primates track time from one instant to the next.2 And even in a research field where no one knows what to expect, the investigations are turning up surprises. The findings cast some doubt on an idea that appeals to many, that the brain has an internal "clock" that somehow ticks ceaselessly away, providing a single reference frame for thoughts and actions.3 Instead, some researchers contend, time may be represented in many brain areas in a manner suited to each area's particular functions and inseparable from the decisions made there. Other researchers say the brain may use the same circuitry, or cells, to measure time, space, and magnitude. ©2003, The Scientist Inc.

Keyword: Biological Rhythms
Link ID: 4470 - Posted: 06.24.2010

Researchers revive age-old questions about mental illness etiology | By Brendan A. Maher It's a scary thought that one could develop a debilitating mental illness such as schizophrenia as easily as catching a cold. Well, it's more complicated than that, say advocates of the so-called infectious hypothesis, which states that viral and possibly bacterial infections occurring at critical points in brain development could increase the risk of mental illness. Everything from influenza to herpes simplex viruses to Toxoplasma gondii has been implicated in elevating risk for schizophrenia, perhaps indirectly through immunological reactions that change brain chemistry or wiring at key developmental stages. Raised, ridiculed, retracted, and rewrought, the hypothesis has morphed for nearly a century. Its current permutation may be gaining ground, though. With better epidemiological studies and animal work emerging, some former scoffers are beginning to accept the notion that, while not a direct cause, infections may factor into schizophrenia's complex gene/environment formula that dictates one's chances for landing somewhere among the less than 1% of people affected worldwide. The Stanley Research Institute's associate director of research, E. Fuller Torrey, has been a notorious proponent of infectious hypotheses since the 1970s. "I wouldn't say we're respectable, but it's no longer ridiculed, which seems like a step forward." BLAMING MOM Though most have eschewed the notion of a schizophrenogenic mother, a healthy environment does start in the womb. Various strands of evidence link increased propensity for schizophrenia to infections during gestation. Past studies uncovered a higher propensity in people born soon after known disease outbreaks such as the 1957 flu pandemic. Other data link increased risks to winter births or reported flu symptoms. ©2003, The Scientist Inc.

Keyword: Schizophrenia
Link ID: 4469 - Posted: 06.24.2010

PDF of a chart about schizophrenia.

Keyword: Schizophrenia
Link ID: 4468 - Posted: 11.03.2003

New studies explore the extensive pruning of axons and dendrites during nervous system development | By Douglas Steinberg A typical neuron's axons and dendrites, when loaded with dye and magnified, resemble long, untended tresses on an extremely bad hair day. They extend wildly, usually to one side, and then bend at weird angles as their ends split into branches and sub-branches. This neuronal coiffure must appear even more chaotic before the nervous system has undergone the developmental equivalent of a crew cut crossed with a topiary trimming. From the late embryonic to early postnatal stage, this pruning process drastically thins out the branches in many axonal and dendritic arbors. Long neuronal offshoots that grew to inappropriate targets simply vanish. Pruning occurs in probably all vertebrates and in many lower animals; neuroscientists have been aware of it for decades. Nevertheless, this phenomenon has garnered much less attention than that paid to other forces and events shaping the nervous system, such as axon guidance and apoptosis. The reason, researchers say, is that pruning is very hard to monitor and manipulate. ©2003, The Scientist Inc.

Keyword: Development of the Brain
Link ID: 4467 - Posted: 06.24.2010

Simple smell tests could help doctors identify people at risk of developing schizophrenia, a study suggests. It has long been known that people with schizophrenia or psychosis are unable to correctly identify smells. But until now scientists were unsure whether this occurred before or after symptoms developed. This latest study, published in the American Journal of Psychiatry, suggests it happens before the first symptoms appear. Dr Warrick Brewer and colleagues at the University of Melbourne examined a group of people, all of whom were deemed to have a very high risk of developing psychosis. They found those who went on to develop schizophrenia, rather than other forms of psychosis, were all unable to identify smells properly. (C) BBC

Keyword: Schizophrenia; Chemical Senses (Smell & Taste)
Link ID: 4466 - Posted: 11.02.2003

By LAUREN SLATER I'm sitting in a room with six terrified people. Outside the window we can hear the roar of Boston's rush hour, cars sputtering at intersections, baseball fans shouting in the streets. Out there it is loud, but in here, at the Center for Anxiety and Related Disorders at Boston University, it is as hushed as a hospital, the faces of the patients slick with sweat. The director of the center, the psychologist David H. Barlow, is one of the leading researchers in the field of fear. He isn't here today, but his methods are guiding this therapy group, which is led by two strikingly young-looking graduate students. It seems somehow fitting that this center, the premier institution for the treatment of anxiety, is located smack-dab in the maze of Boston's crooked and crazy streets. Barlow's method for treating anxiety disorders is surprisingly simple, although its philosophical and clinical implications are anything but. He aims to reduce anxiety not by teaching customary relaxation techniques involving calming mantras or soothing imagery, but by doing just the opposite: forcing the patient to repeatedly face his most dreaded situation, so that, eventually, he becomes accustomed to the sensation of terror. Barlow claims he can rid some people of their symptoms in as little as five to eight days. His treatment promises to be psychotherapy's ultimate fast track, but while many clinicians praise its well-documented results, others take a dimmer view of what one clinician calls ''torture, plain and simple.'' What critics malign as ''torture,'' Barlow calls ''exposure.'' Here's how it works. Ben, for instance, is 31 years old; he has come to the clinic to try to rid himself of panic attacks. His anxieties also stand in the way of his poetry writing, and he is fearful of people criticizing his work. One of his most feared situations is giving a public poetry reading and knowing that the audience is restless. Therefore, the patients and I are instructed to act as bored and rude as possible while Ben, hyped up on coffee, reads his poems aloud. ''Remember,'' says Molly Choate, one of the group leaders, ''as he reads, cough, whisper, laugh, rustle around.'' Copyright 2003 The New York Times Company

Keyword: Emotions; Stress
Link ID: 4465 - Posted: 11.02.2003

By KIRK JOHNSON The number of severe lead poisoning cases among children has sharply declined in New York City over the last 20 years as old peeling paint has been removed from apartments and homes. But thousands of children tested each year still have lead levels in their blood high enough to raise health concerns. At least part of the reason, city health officials and other experts say, may be the broader environment of the city itself: lead that is in the soil, on the streets and underneath dozens of miles of elevated subway, where the steel support structures were painted for decades with lead-based paint. Peeling and chipping indoor lead paint is almost certainly the prime threat to small children, who can eat the paint or breathe its dust, health experts agree. Copyright 2003 The New York Times Company

Keyword: Neurotoxins
Link ID: 4464 - Posted: 11.02.2003

By JERE LONGMAN and JOE DRAPE Last June 13, a test tube of clear liquid arrived by overnight mail at the Olympic drug-testing laboratory at the University of California, Los Angeles. The liquid included residue from a syringe that a tipster said contained an undetectable anabolic steroid. In 21 years as director of the laboratory, Dr. Donald H. Catlin had never encountered a smoking gun like this. He had believed for several years that some athletes were cheating with impunity by using designer steroids, and now he had a chance to prove it. Over the next three months, using high-tech screening devices and low-tech tools like pencil and paper, Dr. Catlin and a team of eight chemists cracked the chemical code of the steroid, tetrahydrogestrinone, or THG, synthesized it and developed a test to catch those who used it. Copyright 2003 The New York Times Company

Keyword: Hormones & Behavior
Link ID: 4463 - Posted: 11.02.2003

Two baboons successfully used analogous thinking to match symbol arrays that were the "same but different" WASHINGTON -- More non-human animals may be capable of abstract thought than previously known, with profound implications for the evolution of human intelligence and the stuff that separates homo sapiens from other animals. A trans-Atlantic team of psychologists has found evidence of abstract thought in baboons, significant because baboons are "old world monkeys," part of a different primate "super family" that -- some 30 million years ago -- split from the family that gave rise to apes and then humans. Chimpanzees, in the ape family, already have demonstrated abstract thought. Now, two trained baboons successfully determined that two differently detailed displays were fundamentally the same in their overall design. Figuring this out required analogical (this is to this as that is to that) reasoning, which many theorists view as the foundation of human reasoning and intelligence. The study is reported in the October issue of the Journal of Experimental Psychology: Animal Behavior Processes, published by the American Psychological Association (APA). In a series of five experiments, Joel Fagot, Ph.D., of the Center for Research in Cognitive Neuroscience in Marseille, France; Edward A. Wasserman, Ph.D., of both the Center for Research in Cognitive Neuroscience and the University of Iowa; and Michael E. Young, Ph.D., of the University of Iowa trained two adult baboons, one male and one female, to use a personal computer and joystick to look at and select grids that had varying collections of little pictures.

Keyword: Intelligence; Evolution
Link ID: 4462 - Posted: 11.02.2003

Robots should have eyes in the back of their heads as well the front. Researchers in the US say a robot's navigation skills could be vastly improved by giving it "omni-directional" vision. A robot on the move must be able to sense whether it is travelling in a straight line or spinning on the spot. But telling the difference is difficult with just a single camera for an eye. Yiannis Aloimonos, a computer scientist at the University of Maryland in College Park, says the best way to understand the problem is to imagine seeing the world through a cardboard tube. Turning your head from side to side gives an image that is hard to distinguish from the view you get if you move sideways. © Copyright Reed Business Information Ltd.

Keyword: Vision; Robotics
Link ID: 4461 - Posted: 06.24.2010

Conservation biologist Andrew Mack of the Wildlife Conservation Society and Josh Jones of the University of California, San Diego, recorded cassowary calls in the jungles of New Guinea. The calls dip down to 23 Hz, just at the threshold of human hearing, they report in the October issue of the journal Auk. The finding may shed light on the purpose of the cassowary's prominent headpiece, or casque. Scientists have theorized that the casques may somehow amplify the birds' calls. But the casques are too small to amplify such deep tones, says Mack, who now suspects that the casques are involved instead in receiving signals. Copyright © 2003 by the American Association for the Advancement of Science.

Keyword: Hearing; Animal Communication
Link ID: 4460 - Posted: 06.24.2010

Trauma victims who showed immediate signs of both depression and post-traumatic stress disorder are more likely to have psychosomatic ailments a year later, according to a new study. The combination of both afflictions increases the incidence of somatic complaints, although this is not the case for either condition standing alone, say Douglas F. Zatzick, M.D., and colleagues from the University of Washington School of Medicine. Psychosomatic symptoms are physical complaints that cannot be medically explained. The research findings appear in the November-December issue of the journal Psychosomatics.

Keyword: Stress; Depression
Link ID: 4459 - Posted: 11.01.2003

— Halloween turns millions of kids into candy-loving monsters with more than ample supply of confections to satisfy their “sweet tooth.” Now, Howard Hughes Medical Institute researchers have moved closer to understanding why some people cannot resist the impulses brought on by sweets. The researchers created mice with the same sweet-tooth preferences as humans by inserting the gene that codes for a human sweet-taste receptor protein into the animals. They also inserted an entirely different receptor gene into the taste cells of mice, thereby producing animals that perceive a previously tasteless molecule as sweet. Both of these experiments demonstrate that receptor molecules on the tongue for both the sweet and “savory” umami tastes are what triggers taste cells on the tongue and palate to transmit taste signals to the brain. Umami taste responds to amino acids such as monosodium glutamate. ©2003 Howard Hughes Medical Institute

Keyword: Chemical Senses (Smell & Taste)
Link ID: 4458 - Posted: 06.24.2010

Predators, not mass suicide, account for Arctic rodents' population cycles, study finds David Perlman, Chronicle Science Editor Lemmings, as everybody knows, breed incessantly, migrate by the thousands every four years and finally rush over cliffs in a panic, hurling themselves into the sea in a dramatic case of population control by mass suicide. So goes the myth, popularized in part by an old Walt Disney nature movie. Now, three European scientists working in the high Arctic tundra have just given the script a drastic rewrite. After 15 years patiently observing a huge lemming population in eastern Greenland, the scientists report in a study appearing today in the journal Science that the "lemming cycle," which has stumped generations of scientists, is driven not by panic, but by predation. ©2003 San Francisco Chronicle

Keyword: Evolution; Stress
Link ID: 4457 - Posted: 06.24.2010

By EMMA ROSS, AP Medical Writer LONDON -- A doctor whose research has been seized upon for the last five years by parents opposed to the measles, mumps and rubella combined vaccine has urged them not to fear the childhood immunization, saying lingering concerns over a link with autism are unfounded. In a letter published this week in The Lancet medical journal, Dr. Simon Murch warned the proportion of toddlers getting the vaccine, known as MMR, has dropped so low in Britain that major measles epidemics are likely this winter. Measles has resurfaced in Britain over the last few years in areas where MMR use has dipped; more children are getting infected every year. Copyright © 2003, The Associated Press Copyright © Newsday, Inc.

Keyword: Autism
Link ID: 4456 - Posted: 06.24.2010