By Eric J. Nestler and Robert C. Malenka White lines on a mirror. A needle and spoon. For many users, the sight of a drug or its associated paraphernalia can elicit shudders of anticipatory pleasure. Then, with the fix, comes the real rush: the warmth, the clarity, the vision, the relief, the sensation of being at the center of the universe. For a brief period, everything feels right. But something happens after repeated exposure to drugs of abuse--whether heroin or cocaine, whiskey or speed. The amount that once produced euphoria doesn't work as well, and users come to need a shot or a snort just to feel normal; without it, they become depressed and, often, physically ill. Then they begin to use the drug compulsively. At this point, they are addicted, losing control over their use and suffering powerful cravings even after the thrill is gone and their habit begins to harm their health, finances and personal relationships. Neurobiologists have long known that the euphoria induced by drugs of abuse arises because all these chemicals ultimately boost the activity of the brain's reward system: a complex circuit of nerve cells, or neurons, that evolved to make us feel flush after eating or sex--things we need to do to survive and pass along our genes. At least initially, goosing this system makes us feel good and encourages us to repeat whatever activity brought us such pleasure. © 1996-2004 Scientific American, Inc

Keyword: Drug Abuse
Link ID: 4938 - Posted: 06.24.2010

Why your brain doesn’t always make the right decision By Eric Haseltine Neuroscientists have long believed that evolution hardwired the brain to amplify slight differences in shading, making it easier to perceive subtle details like a green snake in a green tree. Thus objects on dark backgrounds appear lighter than they are, and those on bright backgrounds appear darker. But science advances by replacing approximate truths with more precise ones, and new research suggests that this scientific “truth” is, at best, incomplete. The two experiments that follow help show why the thinking on this subject is changing. What are the colors of the squares indicated by the arrows in the two figures at right? For most observers, the one on the top looks blue and the one on the bottom looks yellow. But the two squares are actually an identical shade of gray. One possible explanation for this illusion is simultaneous contrast, a process by which your brain makes foreground objects take on the opposite hue of their backgrounds in order to improve your discrimination of subtle color differences. According to this theory, the top square appears blue because the figure is on a mostly yellowish background, while the bottom square looks yellow because it’s set against a predominately bluish background. © 2003 The Walt Disney Company.

Keyword: Vision
Link ID: 4937 - Posted: 06.24.2010

By Blake Gopnik The Washington Post BERKELEY, Calif. - Does a Rembrandt portrait or a van Gogh still life press some special buttons in every human being's brain? Will a red painting speak to us in ways a blue one never could? Are we wired in ways that make every one of us enjoy a smiling bust and shiver at a frowning one? And if our brains determine how art works on us, what does that tell us about art, or us - could studying the way we're wired determine crisply that the "Mona Lisa" is truly great, or do we need some history to tell us how a complex painting speaks, or not, to all its different viewers? The Third International Conference on Neuroaesthetics, subtitled "Emotions in Art and the Brain," was held last month at the Berkeley Art Museum and tried to get a start on answering such questions. It was a showcase for the progress that's been made in figuring out what goes on in the brain when art is seen or made. © 2004 The E.W. Scripps Co

Keyword: Vision
Link ID: 4936 - Posted: 06.24.2010

Homing pigeons are finding their way around Britain by following roads and railways, zoologists claim. They say the birds' natural magnetic and solar compasses are often less important than their knowledge of human transport routes. A 10-year Oxford University study discovered some pigeons turn off at certain motorway junctions and use landmarks to remember where they are. The scientists behind the study were "knocked sideways" by their findings. The pigeons' routes were mapped to within four yards by tiny tracking devices and global positioning system technology. Research team member Dr Tim Guilford said the results were "plain to see". "They don't follow linear lines all the time and sometimes when they're flying at 200 or 300ft above built-up areas it's difficult to see exactly what they are following. (C) BBC

Keyword: Animal Migration
Link ID: 4935 - Posted: 02.08.2004

A drug manufactured from the saliva of vampire bats could make it easier to protect the brain from stroke damage. Normally, most stroke patients should get into hospital for "clot-busting" treatment within a few hours. However, it appears the drug Desmoteplase can make a difference even if given nine hours after the stroke. At an international stroke conference in San Diego, US, researchers claimed it was the "biggest breakthrough" in stroke treatment in 20 years. Most strokes happen when a blood clot lodges and blocks a blood vessel within the brain. This deprives brain cells in that area of the oxygen they need to survive, often leading to brain damage which causes paralysis or weakness in various parts of the body. Doctors have long stressed the importance of getting this kind of stroke victim treated as soon as possible after the stroke, as it has been shown that long-lasting damage can be reduced if drugs are given to break up the clot and restore blood flow quickly. (C) BBC

Keyword: Stroke
Link ID: 4934 - Posted: 02.08.2004

Bruce Bower For more than 60 years, scientists have known that a strip of neural tissue that runs ear-to-ear along the brain's surface orchestrates most voluntary movement, from raising a fork to kicking a ball. A new brain-imaging study has revealed that parts of this so-called motor cortex also respond vigorously as people do nothing more than silently read words. Not just any words get those neurons going, however. They have to be action words—active verbs. As volunteers read a verb referring to a face, arm, or leg action—such as lick, pick, or kick—the motor cortex areas that control the specified action exhibit high rates of blood flow, a sign of intense neural activity, say neuroscientist Friedemann Pulvermüller of the Medical Research Council in Cambridge, England, and his colleagues. For instance, reading the word lick triggers pronounced blood flow in sites of the motor cortex associated with tongue and mouth movements. Copyright ©2004 Science Service.

Keyword: Language
Link ID: 4933 - Posted: 06.24.2010

Study of high-seafood diet points to poison's long-lasting impact. HELEN PEARSON Eating seafood that contains mercury can affect the brain development of children in their adolescence, according to a study of people in the Faroe Islands. The study fuels an ongoing debate about the health effects of a form of mercury called methylmercury, which accumulates in large marine animals such as swordfish and whales. Some researchers think these compounds are toxic only to babies as they develop in the womb, and that older children are unlikely to suffer developmental problems from the poison. © Nature News Service / Macmillan Magazines Ltd 2004

Keyword: Neurotoxins; Development of the Brain
Link ID: 4932 - Posted: 06.24.2010

It's well known that pregnant women who drink alcohol put their unborn children at risk for developing a range of problems. Now, the latest research clarifies how alcohol can harm brain function by uncovering some of alcohol's specific influences on the developing brain. The findings may help researchers devise new methods to improve the diagnosis of alcohol-related impairments as well as new strategies to aid those affected by alcohol exposure before birth. The woman raises her glass and drains the ice-cold draft. She's not drinking alone. An unborn baby joins in. Alcohol, whether from beer, wine, or a cocktail, travels with the blood of a pregnant drinker, enters the womb, and passes to her developing baby. Unfortunately this is no party. In past years, the medical community determined that pregnant women who drink alcohol put their unborn children at risk for developing an array of abnormalities, including fetal alcohol syndrome (FAS), which is characterized by a combination of facial malformations, stunted growth, and disorders of the brain. Impulsivity, poor judgment, inferior reasoning, poor memory, problems paying attention, poor coordination, and other signs of brain impairment also can occur in alcohol-exposed people without all the physical signs of FAS. Copyright © 2004 Society for Neuroscience

Keyword: Development of the Brain; Drug Abuse
Link ID: 4931 - Posted: 06.24.2010

Men and women reported similar levels of pain Pain hurts less when it is inflicted by a woman, researchers have found. Students were asked to put their fingers in a clamp which was tightened until the pain was unbearable. Researchers from the University of Westminster found that people allowed women to turn the clamp much further than men. Dr David Williams, who led the research said the study suggested people do not expect women to inflict as much pain. He said: "This effect is likely to be a result of what participants subconsciously expect, based on socially acquired gender stereotypes - people feel that they are less likely to experience intense pain from a stimulus given by a woman rather than a man. "This effect is less likely to be down to males trying to appear macho in front of a female - a conscious and deliberate act - as the result applied to both genders." (C) BBC

Keyword: Pain & Touch
Link ID: 4930 - Posted: 02.06.2004

Why Brain Structure Makes Unintended Shootings Inevitable by Erik Baard The police killing of an unarmed 19-year-old on a Brooklyn rooftop last month appears to be a tragedy of nanoseconds and eons, a death delivered by a cop firing not because of a conscious decision but an instantaneous neuronal impulse hardwired from the days of our animal ancestors. And there's an obvious subtext of race. The shooter, officer Richard S. Neri Jr., is white. The victim, Timothy Stansbury Jr., was black. Scientific research has a say here too, probing whether our rawest reflexes can be primed by modern fears based on race. Scientists are intensely studying the amygdala, a pair of almond-shaped neuron clusters inside the brain, to understand its role in post-traumatic stress disorder. The amygdala encodes memory with emotional weight, but it also alerts us to sensory information that we associate with danger. It's the jittery small mammal inside us, always awaiting loud noises, sudden movements, and glints of teeth. The more we expect a threat, the more excitable it becomes. Copyright © 2004 Village Voice Media, Inc.,

Keyword: Emotions
Link ID: 4929 - Posted: 06.24.2010

Scientists are trying to genetically engineer cattle that can't get mad cow disease. As this ScienCentral News video reports, a cloned cow would be a tool for further research on the disease. Federal officials announced the U.S.'s first case of mad cow disease, or bovine spongiform encephalopathy, last month. "Mad cow disease is here in the country, on this continent, in North America," says Will Eyestone, professor in the department of large animal clinical science at Virginia Tech. "It is a disease of concern. The more we know about this disease, the better chance we have of controlling it effectively." Unlike other diseases commonly caused by a virus or bacteria, scientists believe mad cow disease is caused by an infectious form of a type of protein called a prion (short for proteinaceous infectious particle). Inside the brain cells of mammals, some types of prions can alter cell structure, destroy the central nervous system, and lead to fatal illnesses such mad cow disease in animals or new variant Creutzfeldt-Jakob disease in people. © ScienCentral, 2000-2003.

Keyword: Prions
Link ID: 4928 - Posted: 06.24.2010

Some parents may think it is undignified or detrimental, but babytalk is essential to the full development of a baby's brain, says a researcher at the University of Alberta. Babytalk, the universal cooing that mothers and fathers do to get their babies' attention, is more important than we may have ever realized, says Dr. David Miall, professor of English at the U of A. Babytalk helps infants to develop an understanding and appreciation of temporal arts, such as literature, music, and dance, and depriving babies of the alliteration, assonance, and other poetic elements inherent in babytalk could hinder their ability to produce and appreciate these arts when they grow up, says Miall, whose research was published recently in the journal Human Nature--An Interdisciplinary Biosocial Perspective.

Keyword: Language; Development of the Brain
Link ID: 4927 - Posted: 02.06.2004

New technique may help reverse paralysis. HELEN R. PILCHER A clot-busting corkscrew may help patients to recover after stroke. The device, which is guided through blood vessels to the brain, retrieves blobs of coagulated blood and can, in some cases, reverse paralysis. The technique has worked for a small group of patients in a US clinical trial. Sidney Starkman from the University of California, Los Angeles and colleagues tested their method on 114 stroke patients. Sixty-one had their clots successfully removed, with 23 making a near-complete recovery. One patient was paralysed down one side and couldn't speak, says Starkman. "We pulled out the clot and instantaneously he was back to normal," he says. The remaining 53 patients were either left paralysed, or died from their clot. © Nature News Service / Macmillan Magazines Ltd 2004

Keyword: Stroke
Link ID: 4926 - Posted: 06.24.2010

By DONALD G. McNEIL Jr. and DENISE GRADY Saying mad cow disease is now "indigenous in North America," an international panel advising the Agriculture Department recommended a ban yesterday on feeding all animal protein to cattle. The panel, made up of experts from Britain, New Zealand, Switzerland and the United States, also recommended testing many more head of cattle, adopting rapid European tests and removing brains, spinal columns and intestines of all cattle older than 1 from food supplies. Convened after the first cow infected with bovine spongiform encephalopathy in this country was found in December in Washington State, the panel released its report at a conference in Maryland. Its chairman, Dr. Ulrich Kihm, a Swiss veterinarian, said the United States "could have a case a month" of mad cow disease if it was doing enough testing, Reuters reported. Dr. Kihm made the estimate based on the experiences of European countries. But he did not predict an outbreak like the one in Britain, where hundreds of thousands of infected cows were found and more than 100 people died of a degenerative brain disease. Copyright 2004 The New York Times Company

Keyword: Prions
Link ID: 4925 - Posted: 02.05.2004

Lynn A. D'Andrea, a sleep specialist at the University of Michigan Medical School, explains. Snoring is the sound produced by vibrating structures of the upper airway, typically during inhalation. Any membranous part of the airway lacking cartilaginous support, including the tongue, soft palate, uvula, tonsillar pillars and pharyngeal walls, can vibrate. When you sleep, muscle tone throughout your body decreases, or becomes hypotonic. This relaxation of the upper airway muscles during sleep may decrease the size of the airway space and cause airflow limitation and turbulence. It is the combination of turbulent airflow through the hypotonic airway structures that results in the harsh vibratory noise known as snoring. Snoring is not an illness, but it is a symptom. Just as a cough can be a symptom of pneumonia, snoring can be a symptom of obstructive sleep apnea. Obstructive sleep apnea is a disorder characterized by snoring, labored breathing and repetitive obstructed pauses or gasps in a person’s breathing during sleep. The obstructed pauses result from complete obstruction or blockage of the airway and may be associated with decreases in oxygen levels. Typically, the obstruction is terminated by an arousal—that is, the snorer briefly wakes up--leading to fragmented, less restful sleep. Obstructive sleep apnea can cause excessive daytime sleepiness, decreased attention and poor concentration, and decreased energy levels. The consequences of these behavioral problems can be quite severe and include motor vehicle accidents if a sufferer becomes inattentive or falls asleep while driving. Obstructive sleep apnea is also causally related to vascular complications such as hypertension. © 1996-2004 Scientific American, Inc.

Keyword: Sleep
Link ID: 4924 - Posted: 06.24.2010

By Jennifer Viegas, Discovery News — A new study suggests that bumble bees possess innate preferences for flowers that are yellow and/or blue, and patterned with a radial design. Gardeners, however, would be ill-advised to run out and buy flowers based on color and pattern alone, because the study adds that food is what ultimately matters to bumble bees. Flowers that bees at first find visually irresistible will be avoided over time if the don't provide bees with a good source of nectar and/or pollen. For the study, published in the current issue of Animal Behaviour, researchers created a 12-arm maze that held flower-like images showing various colors and designs. "Flower-naive bees," or bees that had never before foraged from flowers, were introduced to the maze. Copyright © 2004 Discovery Communications Inc.

Keyword: Vision; Learning & Memory
Link ID: 4923 - Posted: 06.24.2010

Exclusive from New Scientist Print Edition. Some people may be aware that a scene they are looking at has changed without being able to identify what that change is. This could be a newly discovered mode of conscious visual perception, according to the psychologist who discovered it. He has dubbed the phenomenon "mindsight". Ronald Rensink, based at the University of British Columbia in Canada, showed 40 people a series of photographic images flickering on a computer screen. Each image was shown for around a quarter of a second and followed by a brief blank grey screen. Sometimes the image would remain the same throughout the trial; in other trials, after a time the initial image would be alternated with a subtly different one. In trials where the researchers manipulated the image, around a third of the people tested reported feeling that the image had changed before they could identify what the change was. In control trials, the same people were confident that no change had occurred. The response to a change in image and control trials was reliably different. © Copyright Reed Business Information Ltd.

Keyword: Vision
Link ID: 4922 - Posted: 06.24.2010

Montreal, - New research findings from the Research Institute of the McGill University Health Center (MUHC) provide hope for patients with multiple sclerosis (MS), one of the most common and devastating diseases of the nervous system. These findings, published in today in Neuron, characterize an enzyme that plays a central role in the onset and progress of MS. " We have identified a key enzyme that triggers MS-like disease in an animal model," says MUHC neuroscientist and Professor of Medicine at McGill University, Dr. Sam David. "We also show that blocking this enzyme has a remarkable effect in preventing disease and relapses." MS, an autoimmune disease of the nervous system, affects approximately 35,000 young adults in Canada. It is twice as prevalent in females. MS is an inflammatory disease in which the body's own immune system attacks the insulating membranes surrounding nerve fibers. This damage results in loss of sensations and paralysis. Although genetic, infectious or environmental factors are thought to induce MS, the exact cause of the disease is still not known.

Keyword: Multiple Sclerosis
Link ID: 4921 - Posted: 02.05.2004

Rodents missing a single protein can detect the weakest scents. HELEN R. PILCHER Researchers have created a mouse with a superior sense of smell. The animals should help shed light on the biology of odour detection, which could one day help humans crank up our ability to smell. Debi Fadool from Florida State University in Tallahassee and her colleagues were intrigued by a strain of genetically modified mice that lack a protein called Kv1.3. This molecule is used in nerve communication, and is also found in odour-related brain regions. So the team tested the animals to see if their sense of smell was different from an ordinary mouse. To their surprise, removing the protein actually had a beneficial effect on the mice. Those without Kv1.3 could find hidden smelly treats such as peanut-butter crackers twice as quickly as those with the protein. © Nature News Service / Macmillan Magazines Ltd 2004

Keyword: Chemical Senses (Smell & Taste)
Link ID: 4920 - Posted: 06.24.2010

– BETHESDA, MD – As the US population ages, there is an increasing effort to understand the underlying mechanisms that contribute to learning and memory. This effort could be of critical importance to scientists trying to decipher how the molecular genetic mechanisms of learning and memory are disrupted or impaired. The results of a new study provide evidence that individual differences in some cognitive functions may have a genetic basis. A New Study The authors of the study are Nelson Ruiz-Opazo, of the Section of Molecular Medicine, Boston University School of Medicine, Boston, MA, and John Tonkiss, from the Center for Behavioral Development and Mental Retardation, Boston University School of Medicine, Boston, MA. Their study, entitled "X-Linked Loci Influence Spatial Navigation Performance in Dahl Rats," now appears in the Articles in Press section of Physiological Genomics, one of one of 14 scientific journals published monthly by the American Physiological Society (APS) (www.the-aps.org).

Keyword: Genes & Behavior; Learning & Memory
Link ID: 4919 - Posted: 06.24.2010