Rockville, MD ––Dogs' ability to discriminate brightness is about half as good as that of humans, according to a study appearing in Volume 4, Issue 3 in the Journal of Vision. In research conducted by scientists from the Veterinary University of Vienna and the University of Memphis, dogs showed a surprising lack of ability to discriminate between grey cards that varied in brightness, says researcher Ulrike Griebel of the University of Memphis. While a great deal is known about dogs' visual acuity and the cellular components of their eyes, there is a paucity of information about their ability to discriminate brightness, says Griebel. Furthermore, she notes that there is relatively little information on how well other animals discriminate brightness. The researchers tested three police dogs--two Belgian shepherds and a German shepherd. The dogs faced a series of pairs of grey squares, which differed in brightness. The task required the dog to determine how much the one square differed in brightness from the other. The correct choice was rewarded with a food treat. The dogs needed a far greater difference in brightness (known as the Weber fraction) than do humans to discriminate between two squares. For the Belgian shepherds the Weber fraction was 0.27; for the German shepherd it was 0.22. Although the researchers did not test humans in their study, previous studies found that humans need a Weber fraction of 0.14 to be able to discern a brightness difference.

Keyword: Vision; Evolution
Link ID: 5716 - Posted: 06.24.2010

Drug targets female brain to boost sex drive. LAURA NELSON Ever since Viagra worked for men - and didn't for women - researchers have been searching for a drug that turns women on. Now a hormone-like drug may hit the spot, by targeting not the genitals, but the brain. The way Viagra works is simple; it dilates blood vessels, increasing blood flow in the genitals. This purely physical effect seems to be sufficient for most men to perform and enjoy sex. But women are more complicated. "The difference between male and female orgasms is that brain effects are more important in women," says John Stevenson, an endocrinologist at the Royal Brompton and Harefield NHS Trust. In other words, physical arousal doesn't happen without desire. And that can be much harder to trigger. "People may get the sensory input, but they don't think, 'ooh I'm horny'." James Pfaus, Behavioural neurobiologist, Concordia University, Montreal © Nature News Service / Macmillan Magazines Ltd 2004

Keyword: Sexual Behavior
Link ID: 5715 - Posted: 06.24.2010

When an animal touches something, it stimulates a chain of nerve cells running from the body surface to the spinal cord to the brain. This system is capable of recording a huge variety and intensity of sensations. Amazingly, however, it all occurs through the firing -- or lack of firing -- of these neurons. How that firing, in electrical pulses called "action potentials," records sensory information is a mystery that neuroscientists have been slowly figuring out over 50 years. Last week, a team of researchers at the University of Maryland School of Medicine reported in the journal Science that they had taken a large step forward. Lauren M. Jones, a graduate student working with Asaf Keller, studied neurons hard-wired into the whisker follicles of rats. In those animals, whiskers are nearly as important as eyes in perceiving their surroundings. Certain neurons only fire when a whisker is moved in one direction but not in a different one -- a fact known for a long time. What Jones discovered is how that information is encoded in the timing of a cell's firing. © 2004 The Washington Post Company

Keyword: Pain & Touch
Link ID: 5714 - Posted: 06.24.2010

A new charity has pledged to stamp out "quack" interventions for people with autism and similar disorders. The Autism Intervention Research Trust says it will fund studies to see which treatments work and which ones do not. Geoffrey Maddrell, its chairman, said there was no scientific evidence to support some existing treatments. He said the charity would also fund research into new ways of treating autism and related disorders, which affect 500,000 Britons. Mr Maddrell said independent research was needed to help people with the condition. "Hundreds of treatments and other methods of intervention are available but few have been scientifically evaluated and there are still large numbers for whom there is currently no effective help. "In many instances, exaggerated or misleading claims are made for specific approaches. "In the UK, only 8% of autism research activity is currently concerned with intervention and the new research trust has been established to address this vital need". (C)BBC

Keyword: Autism
Link ID: 5713 - Posted: 06.28.2004

By BARRY MEIER Forest Laboratories has said a recently concluded test found that its antidepressant Lexapro did not help depressed children and adolescents, an announcement that comes amid the growing controversy over clinical drug tests. The company's announcement is significant because Lexapro contains essentially the same active ingredient as another Forest antidepressant, Celexa, which is widely prescribed for pediatric use. The company made its announcement late Thursday, when it also released a second statement addressing how it had handled its disclosure of results from two trials of Celexa in depressed children. The New York Times reported Monday that Forest officials had not told a medical journal about a failed unpublished study in 2002 of Celexa use in children and adolescents, before the journal published an article this month about a separate test indicating the drug could help young people. Some of the recent article's authors were Forest employees. Copyright 2004 The New York Times Company

Keyword: Depression; Development of the Brain
Link ID: 5712 - Posted: 06.28.2004

Of all the unsolved mysteries of the human body, it is the brain that most rigidly resists our efforts at understanding it; and that lack of understanding is costing us increasingly dear. Mental illness is reaching epidemic levels. The World Health Organisation claims that mental health problems "are fast becoming the number-one health issue of the 21st century". Clinical depression is the biggest international health threat after heart disease. At the same time, there is a growing dissatisfaction with the drug treatments available. In the UK, the number of prescriptions for antidepressants has more than doubled in 10 years, with 80% of GPs admitting they overprescribe drugs such as Prozac and Seroxat because of the lack of alternative forms of treatment. But though they might not be available on the NHS just yet, alternatives are starting to emerge - and with some promising results. Later this month Dr David Servan-Schreiber, a clinical professor of psychiatry and founding member of Medecins Sans Frontières in the US, will visit Britain to launch his book, Healing Without Freud or Prozac, which has already received an enthusiastic response in Belgium, Switzerland and Canada, where it has sold half a million copies. After a career in conventional medicine, Servan-Schreiber's theory is that exercise can be as effective in treating depression and stress as antidepressants. "It is not that I am against antidepressants," he says. "But there are some natural methods of treatment that have been demonstrated to work for milder forms of depression. It doesn't make any sense to ignore them any longer." Guardian Unlimited © Guardian Newspapers Limited 2004

Keyword: Depression; Schizophrenia
Link ID: 5711 - Posted: 06.24.2010

John Travis Find the kid a sports agent. Researchers studying an unusually muscular tot have found that he has gene mutations similar to ones that produce abnormally brawny cattle and mice. Less-severe variations in the same gene may underlie the success of some athletes, the scientists speculate. The boy's mutations disrupt both copies of the gene encoding a muscle protein called myostatin. Previous studies of the gene in animals had suggested that myostatin restrains muscle growth during development and adult life. But scientists didn't know whether the protein serves the same function in people. The boy's powerhouse physique "says pretty definitively that myostatin plays the same role in humans that it does in mice and cattle," concludes Se-Jin Lee of Johns Hopkins Medical Institutions in Baltimore. If so, he adds, then drugs to block myostatin might have some benefits in people with muscle-wasting diseases. Lee is a member of the international group of investigators who have studied the boy since 1999 and now report their results in the June 24 New England Journal of Medicine (NEJM). Copyright ©2004 Science Service.

Keyword: Muscles; Genes & Behavior
Link ID: 5710 - Posted: 06.24.2010

Drugs widely used to treat Alzheimer's disease have little actual benefit, controversial research suggests. The National Institute for Clinical Excellence recommended in 2001 that cholinesterase inhibitors should be prescribed on the NHS. But a five-year Lancet study by the University of Birmingham concludes that routine prescribing of the drugs is a waste of scarce resources. Alzheimer's experts, however, have challenged the finding. The drugs cost about £1,000 per person per year. In total 565 patients with mild to moderate Alzheimer's disease took part in the study. They were given either the cholinesterase inhibitor donepezil (Aricept) or a dummy pill. The main aim of the study was to assess whether donepezil delayed progress of disability or the need for institutional care. The study also looked at the optimal dose and length of treatment, and what effect donepezil has on the mood and behaviour of patients, their ability to undertake daily activities, and whether donepezil relieved the burden on carers. Lead researcher Professor Richard Gray said: "We've known for some time that patients do better on memory tests when they take these drugs but the improvements were small and we wanted to find out whether patients got benefits that really mattered to them - for example, could they go for a walk and find their way home. (C)BBC

Keyword: Alzheimers
Link ID: 5709 - Posted: 06.25.2004

By DENISE GRADY The most widely prescribed drug for Alzheimer's disease, Aricept, does not delay the onset of disability or the need for a nursing home, British researchers are reporting today. The researchers say that the drug has "disappointingly little overall benefit" and is not cost-effective, and that better treatments are needed. Experts in the United States are already divided over the usefulness of Aricept and related drugs, and the study is unlikely to end the debate. Most studies have shown that the drugs can produce small improvements in scores on mental tests, but it is not clear whether the gains translate into anything helpful in real life. Even the drugs' staunchest advocates say that they offer modest benefits at best, affording perhaps a short delay in a patient's decline. But when small changes in functioning occur, it may be hard to tell whether they are owing to the drug or to the ups and downs of the disease itself. The new report, being published in today's issue of The Lancet, the British medical journal, is based on a study of 565 patients with mild to moderate Alzheimer's disease who were assigned at random to receive either Aricept or a placebo and were then followed for up to three years. Copyright 2004 The New York Times Company

Keyword: Alzheimers
Link ID: 5708 - Posted: 06.25.2004

Blind, deaf, and hungry, a newborn mouse can't care for itself. Take away its mother, and a pup will scream bloody murder to get help. But if the neuronal receptors that respond to morphine are also taken away, the pup just doesn't seem to care. The finding may shed some light on roots of emotional attachment disorders, as well as drug abuse. The research, reported in the 25 June issue of Science, supports pharmacological evidence from a variety of animals that the opioid reward system helps wee ones bond with others. Opioids are best known as painkillers. They have other effects, too; morphine will turn the shrieks of lonely baby guinea pigs into whimpers. Francesca D'Amato of the CNR Institute of Neuroscience, Psychobiology, and Psychopharmacology in Rome and colleagues tested infant attachment in mouse pups born to parents genetically designed to lack both copies of the ì-opioid receptor gene. First, the researchers removed mom from the living quarters and, 5 minutes later, subjected the pups to a new environment. Normal 8-day-old pups screamed incessantly when placed into a beaker with clean bedding; they screamed about half as much when the beaker contained old fluff that smelled like mom. The mutant mice, though, hardly screamed at all. The lack of screeching was not due to an inability to smell or react to adverse circumstances: When threatening males were near, the mutant pups squealed even more than the normal pups, and all pups freaked comparably when placed in a frigid beaker. In addition, the mutant pups weren't able to discriminate between moms--when given a choice between their own place or a strange mom's nest, all of the normal pups chose their own place. But only a third of the pups lacking the ì-opioid receptor went home. Copyright © 2004 by the American Association for the Advancement of Science.

Keyword: Drug Abuse; Development of the Brain
Link ID: 5707 - Posted: 06.24.2010

Honeybees can precisely regulate the temperature of their nest – and they do it thanks to genetically determined variations in their individual thermostats. The new research has revealed one of the few known benefits of the high genetic diversity found in honeybee colonies. Maintaining a nest temperature of between about 32°C and 36°C is vital during spring and summer, when eggs are developing and hatching. “If they don’t keep the nest at this temperature, the brood won’t develop properly,” says Julia Jones of the University of Sydney, Australia, who led the work. If the temperature drops too low, the worker bees huddle together around the brood to keep it warm. If it gets too high, they stand at the nest entrance and use their wings to fan out hot air. The new work shows that bees with different fathers start fanning at slightly different temperatures. This stops sudden colony-wide shifts between warming and cooling behaviours, and keeps the temperature in the nest more constant. “It’s been shown before that honeybees with different genotypes have different thresholds for certain things – for instance, they’re attracted to different concentrations of nectar," says Jones. "But this is the first time any benefit has been shown from different behaviour thresholds based on genotype in the bees.” © Copyright Reed Business Information Ltd.

Keyword: Genes & Behavior
Link ID: 5706 - Posted: 06.24.2010

ST. THOMAS, U.S. Virgin Islands, /PRNewswire/ -- Legendary biologist Seymour Benzer, whose half century-long career has transformed our understanding of the brain and profoundly influenced generations of scientists, has been selected by an international panel of experts in neuroscience to receive the inaugural 2004 Neuroscience Prize of the Peter Gruber Foundation. Each year the Foundation will present a gold medal and a $200,000 unrestricted cash award to an outstanding scientist who has contributed to fundamental advances in the field of neuroscience. This year's prize will be presented on October 23 at the annual meeting of the Society for Neuroscience in San Diego, California. Born in New York City in 1921, Seymour Benzer received his B.S. in physics from Brooklyn College in 1942 and his Ph.D. in physics from Purdue University in 1947. After beginning his career as a solid-state physicist, he switched to biology in 1949. He was on the faculty of Purdue from 1945 until 1967 when he accepted a professorship at the California Institute of Technology where he is still an active Emeritus professor today. In the early 1960s, after having made several major contributions to the understanding of gene structure and the genetic code, Professor Benzer switched fields again and inaugurated and developed the new and immensely important field of neurogenetics. His deceptively simple approach was based on the premise, confirmed by his subsequent work, that the molecular underpinning of neural function and behavior could be dissected by using ingenious genetic screens to isolate behavioral mutants one gene at a time. Using the fruit fly, Drosophila, he altered one gene after the next and showed that a single gene mutation can give rise to a wide variety of behavioral alterations, including aberrations in courtship, in circadian rhythm, and in memory and learning. These studies have revolutionized the field of behavioral genetics and have shown how, through the genetics of the humble fruit fly, the mysteries of how the human brain develops, functions, and becomes sick can be unraveled. Copyright © 2004 Yahoo! Inc.

Keyword: Genes & Behavior
Link ID: 5705 - Posted: 06.24.2010

Scientists at The Scripps Research Institute and the University of California, San Diego (UCSD) School of Medicine have demonstrated that the action of a protein called CBP is essential for the stabilization of long-term memory, a discovery that may help children with a rare but debilitating developmental disorder. They found that when the functions of normal CBP is suppressed in adult rodents, the animals had trouble forming long-term memories, suggesting that CBP is required for the formation of long-term memory and that defects in CBP are involved in cognitive dysfunction. Furthermore, the scientists found that they were able to correct this defect by administering a drug that restored CBP's function. "This is significant," says Mark Mayford, Ph.D., an associate professor of cell biology and a member of the Institute for Childhood and Neglected Diseases at Scripps Research. Before moving to Scripps Research four years ago, Mayford was a faculty member at UCSD, where together with another UCSD scientist Edward Korzus, Ph.D., they initiated the research. "There is a link between this molecule and very severe problems in humans," Mayford added, noting that the findings may be significant for children with the rare but severe developmental disorder known as Rubinstein-Taybi syndrome, which causes growth and mental retardation and several anatomical abnormalities. These children have mutations in their CBP genes.

Keyword: Learning & Memory
Link ID: 5704 - Posted: 06.24.2004

CHAPEL HILL -- By combining the results of 22 studies, University of North Carolina at Chapel Hill researchers have found that a specific form of the gene APOE very slightly increases the risk of Parkinson's disease, even though the same gene is protective in Alzheimer's disease. The researchers also found that the APOE-4 form of the gene, which has long been linked to an increased risk of Alzheimer's disease, is not a risk factor in Parkinson's disease. A report of the findings appears this week in the June issue of the journal Neurology. "It basically shows that neurodegenerative diseases may differ in significant risk factors, contrary to prevailing views," said lead author Dr. Xuemei Huang, assistant professor of neurology in UNC's School of Medicine. The gene APOE refers to apoliprotein E, which takes three forms, or alleles: APOE-2, -3 and -4. These and other APO genes transcribe apolipoproteins, protein particles involved in lipid metabolism that shuttle these fatty acids, including cholesterol, through the body. "APOE-4 is a major susceptibility gene for sporadic and familial Alzheimer's disease and has been associated with poor clinical outcome in people with acute head injury and stroke," Huang said. "In the brain, apolipoprotein E-4 may be involved in neuron repair and in the removal of dead cells, so if you have APOE-4, you may be at higher risk of Alzheimer's disease or poor recovery from stroke and brain injury."

Keyword: Parkinsons; Alzheimers
Link ID: 5703 - Posted: 06.24.2004

The fat-tailed dwarf lemur has become the first primate proven to hibernate through the winter. The rat-sized lemur curls up in tree holes to slumber through the dry winter season, despite living in tropical Madagascar, where winter temperatures can still exceed 30°C. It spends seven sleepy months living off the fat of its portly tail. But until now its disappearance during the winter had been a matter of speculation, and lab studies had been unable to get the lemurs to hibernate. Kathrin Dausmann at Phillips University, Marburg, Germany, and her colleagues have now proven that the lemurs really do hibernate - and they are the first primates and tropical animals to show this behaviour. The team observed the physiological changes that the lemurs undergo. Unlike other hibernators, the lemurs do not regulate their body temperatures whilst dormant. The temperatures vary widely - by almost 25°C - and are determined by how well or badly the primates' tree holes are insulated. © Copyright Reed Business Information Ltd.

Keyword: Biological Rhythms
Link ID: 5702 - Posted: 06.24.2010

BOSTON - A genetic mutation in "mighty mice" is also found in a German boy with unusually large muscles, scientist say. The four-year-old's muscles are roughly twice as large as other children his age. Researchers found he has an inherited mutation in the myostatin gene, boosting muscle growth and reducing fat. "This is the first evidence that myostatin regulates muscle mass in people as it does in other animals," said Dr. Se-Jin Lee, a professor of molecular biology and genetics at Johns Hopkins University in Baltimore, and a co-author of the study. Naturally bulky cattle such as Belgian Blues also lack myostatin, the researchers have found. Lee's team wants to explore if interfering with myostatin can slow down muscle loss in muscle wasting diseases such as Duchenne muscular dystrophy. About 850 males in Canada have the disease. Seven years ago, Lee's team created mice that are twice as brawny as normal by blocking the mysotatin gene. Both Lee and his university would share in royalties if the research results in any commercial therapies. Copyright © CBC 2004

Keyword: Muscles
Link ID: 5701 - Posted: 06.24.2010

BY JAMIE TALAN Can't keep a tune? You may get to blame your brain. People who can't discriminate between musical tones suffer from amusia, or tone deafness, and Canadian researchers say they have identified a region in the brain they believe is responsible. They are set to deliver preliminary findings today at an international meeting in Montreal on music and the brain. Krista Hyde and her colleagues at the University of Montreal have been scanning the brains of 20 people who've been tone deaf since birth, and have narrowed the hunt to the right auditory cortex, an area of the brain that processes pitch perception. Amusia is no laughing matter, Hyde, a doctoral student, says. Music is such a major element of our culture, she said, that the condition "robs them of their experience of music. ... A beautiful symphony can sound like noise." The researchers suspect that as much as 4 percent of the world's population have a congenital brain abnormality that renders them tone deaf. Others can acquire amusia following head trauma or stroke. Of 100 people who responded to ads seeking people who can't carry a tune, Hyde said only 20 qualified for a true diagnosis of amusia - indicating many who think they're tone deaf instead simply aren't good vocalists. Copyright © 2004, Newsday, Inc.

Keyword: Hearing
Link ID: 5700 - Posted: 06.24.2010

Smoking cigarettes cuts an average of 10 years off a person's life, a landmark study suggests. But it also shows that quitting at any age reduces the risks of dying from smoking-related diseases. The findings, published in the British Medical Journal, are the culmination of a 50-year study involving 34,439 men. The study, which began in 1951, was the first to confirm the link between smoking and lung cancer exactly 50 years ago. All of those involved in the study were born between 1900 and 1930 and all worked as doctors. They were each asked about their smoking habits at the start of the study in 1951. Researchers contacted them periodically over the next 50 years to see if those habits had changed. They also gathered information on those who died during the period. They have now analysed that data. They found that men who have never smoked lived on average 10 years longer than those who smoked for most of their lives. Men who smoked were at least twice as likely to die before the age of 70 as non-smokers. They were up to three times more likely to die before they were 90 compared to those who never took up the habit. (C)BBC

Keyword: Drug Abuse
Link ID: 5699 - Posted: 06.23.2004

By ANAHAD O'CONNOR THE FACTS Most Americans relish the thought of sleeping late, and experts have traditionally recommended eight hours of rest each night. But a 2002 study found that getting more than seven hours of sleep each night was associated with a shorter life span. Several studies since then, including one this year by researchers at Brigham and Women's Hospital in Boston, also found a link. The 2002 study examined data on more than a million Americans over the age of 30 between 1982 and 1988. The risk of dying in that period climbed as subjects went above seven hours of sleep. Those who averaged eight hours a night, the study found, had a 12 percent increased chance of death. Other researchers have also found that life expectancy declines as sleep falls below seven hours, but not as steeply as it does with eight hours or more, said Dr. Jerome M. Siegel, of the University of California, Los Angeles. Most sleep experts are reluctant to draw conclusions because the findings are based on correlations, which cannot show cause and effect. People who sleep longer may have illnesses that cause fatigue and earlier death. THE BOTTOM LINE Averaging more than seven hours of sleep a night is associated with a shorter life span, though whether poor health or too much sleep accounts for the link is unclear. Copyright 2004 The New York Times Company

Keyword: Sleep
Link ID: 5698 - Posted: 06.23.2004

Poets and songwriters will be devastated to hear it: The eyes don't smile after all. Neither do they sadden, according to new research using Mona Lisa's portrait. Those two emotions are the domain of the mouth, it turns out. Similar research could help pinpoint other emotions, or help determine the brain defects in people with visual problems such as the inability to recognize faces. Human facial expressions are subtler than they look, and it's hard to determine the source of emotional information. One technique researchers have used is to show volunteers parts of a face and ask what emotion they see. A different technique allows expressions to "evolve" on an image, allowing researchers access to the whole expression at once. To determine what features make people look happy or sad, visual neuroscientists Christopher Tyler and Leonid Kontsevich of the Smith-Kettlewell Eye Research Institute in San Francisco evolved expressions on The Mona Lisa. The researchers added noise to her ambiguous expression, making the image look like a fuzzy TV screen, then asked subjects to rate her emotion on a four-point scale of happy to sad. The researchers then averaged all of the noisy images in each category of emotion, revealing the subtleties in the facial features needed to spell out happiness or sadness. To determine whether the eyes and the mouth worked together to evoke emotion, the team laid the composite happy or sad noise on just the upper or lower half at a time. Overlaying the mouth half caused Mona to grin or frown, but overlaying the eyes conveyed no emotion. The researchers replicated the finding with a photograph of a woman with an ambiguous expression. "The eyes are well-known to be the window on the soul, so we expected to see an effect of the eyes," says Tyler. Instead, the eyes might express intensity, he speculates. "Perhaps they are the window on the spirit." Visual psychophysicist Richard Murray of the University of Pennsylvania in Philadelphia is also surprised. In addition to learning about expressions, "we can use this technique on people with visual deficits to determine what's going wrong in their brain," he says. --MARY BECKMAN Copyright © 2004 by the American Association for the Advancement of Science.

Keyword: Emotions
Link ID: 5697 - Posted: 06.24.2010