Regular exercise can benefit the body in a number of ways, from aiding weight loss to increasing energy levels and improving cardiovascular health. Findings published online this week by the Proceedings of the National Academy of Sciences bolster the notion that the brain, too, can profit from physical activity. Results of rat studies indicate that exercise can stimulate the recovery of injured neurons. Previous research had linked physical exertion with higher levels of neuronal growth factors known as neurotrophins in the spinal cord and skeletal muscles. In the new work, a team of researchers led by Raffaella Molteni of the University of Milan and Jun-Qi Zheng of the A. I. DuPont Hospital for Children in Wilmington, Del., tested whether these exercise-related changes affect the brain’s ability to form new connections. The scientists gave rats access to a running wheel for periods ranging from zero to seven days. When they tested cultured cells taken from the animals, they found that those from the runners grew longer extensions known as neurites and that there was a direct correlation between how far the rats ran and how long the neurites became. © 1996-2004 Scientific American, Inc. All rights reserved

Keyword: Development of the Brain
Link ID: 5523 - Posted: 06.24.2010

A pair of scientists has proposed a new model for behavioral development among social insects, suggesting that a higher male susceptibility to disease has helped shape the evolution of the insects' behavior. What might be called the "sick-male" theory has been proposed by animal behaviorists Sean O'Donnell of the University of Washington and Samuel Beshers of the University of Illinois at Urbana-Champaign, and appears in the current issue of Proceedings Biological Sciences, published by the Royal Society of London. Among behaviors possibly affected are the division of labor between males and females and the relative social isolation experienced by males in many social insect colonies. The researchers looked at Hymenoptera, an order of insects, including bees, ants and wasps, some of which have highly complicated societies and an unusual genetic makeup. These insects are called haplodiploids because males and females have a different number of sets of chromosomes. The females, like most animals, including humans, are diploid and have two sets of chromosomes, one from each parent. Hymenopteran males, however, hatch from unfertilized eggs and are haploids with just one set of chromosomes.

Keyword: Evolution; Sexual Behavior
Link ID: 5522 - Posted: 05.25.2004

In laboratory experiments, women -- but not men -- who had been exposed to frustrating noise stress ate more cheese, chocolate, potato chips and popcorn after the stressful session was over. Dr. Laura C. Klein, assistant professor of biobehavioral health who led the study, says, "Although other researchers have shown that both men and women eat more during stressful periods, this is the first study to show that eating is affected in some individuals after a stress is stopped. "In daily life, people often rise to the occasion to deal with stress," she adds. "The real window of vulnerability may be after the stress is over. For example, women exposed to a week of frustrating job stress could be especially vulnerable to overeating on the weekends."

Keyword: Stress; Obesity
Link ID: 5521 - Posted: 05.25.2004

Caution urged for pregnant women as rats bear frigid sons. HELEN R. PILCHER Expectant mothers who take aspirin may produce sons with unusually low libidos, a rat study suggests. It is not known whether a similar effect occurs in humans, but the research reinforces the need for prudence when taking any medication during pregnancy. Pregnant rats supped on water laced with soluble aspirin for two weeks around the time they gave birth. But as their sons matured, their sex drives didn't. The males were slower at initiating sex than normal littermates, taking two to three times longer to mount females. They were also less likely to penetrate females and less likely to ejaculate, the researchers report in Nature Neuroscience. © Nature News Service / Macmillan Magazines Ltd 2004

Keyword: Sexual Behavior
Link ID: 5520 - Posted: 06.24.2010

ATLANTA -- Researchers at the Yerkes National Primate Research Center of Emory University are the first to demonstrate a combination of drug therapies targeting the region of the brain that controls drug abuse and addiction significantly reduces cocaine use in nonhuman primates. These findings, which appear in the June issue of the Journal of Pharmacology and Experimental Therapeutics, have implications for developing treatments for cocaine addiction in humans. Led by Leonard Howell, PhD, an associate professor in Yerkes' Neuroscience Division, the Yerkes researchers observed the innovative combination of dopamine transporter (DAT) inhibition and serotonin transporter (SERT) inhibition was effective in limiting cocaine use in rhesus macaques who are trained to self-administer cocaine. "It appears DAT inhibition serves to substitute for cocaine, while SERT inhibition may limit the abuse potential of the medication," said Howell. "Our results, therefore, showing a combination of DAT and SERT inhibition were more effective than either alone are very promising." This first-time finding was the promising end result of a several-step process. Howell and his colleagues began by administering a pretreatment of DAT inhibitors to confirm their effectiveness in reducing drug use. DAT inhibitors have long been used in addiction studies because they elicit reinforcing properties in the brain similar to those experienced as a result of taking cocaine.

Keyword: Drug Abuse
Link ID: 5519 - Posted: 05.25.2004

By DENISE GRADY Squeeze my hand, Stephen," the surgeon called. "Wiggle your feet." In an operating room at New York Weill Cornell Medical Center, doctors watched intently as Stephen R. Neiley III, roused from general anesthesia, gave a squeeze and a wiggle and went back to sleep. Reassured that the electrodes they had just implanted in his brain had done no harm, they went back to work. The next step was to tunnel wires from the electrodes through Mr. Neiley's scalp and neck to a pacemaker-like gadget that would be implanted in his chest. The operation was an experiment, with a goal that Mr. Neiley, 51, has been pursuing for 10 years: to stop or at least diminish the epileptic seizures that have played havoc with his life. Electrically stimulating the brain, in a region called the anterior nucleus of the thalamus, has helped prevent seizures in animals and people, in preliminary studies. Copyright 2004 The New York Times Company

Keyword: Epilepsy
Link ID: 5518 - Posted: 05.24.2004

The discovery of a cow suffering from bovine spongiform encephalopathy (BSE) in Washington State at the end of last year brought fears of mad cow disease to the U.S. New findings provide further insight into how prions, the misshapen proteins behind the transmissible spongiform encephalophathy (TSE) diseases, behave. Prions are most often associated with organ tissue but recent findings have indicated that they can accumulate in the muscles of rodents and humans who have succumbed to TSEs. According to a report published online today by the journal Nature Biotechnology, prions can be detected in the muscles of sheep infected with the TSE known as scrapie several months before the disease can be clinically diagnosed. Olivier Andreoletti of National Veterinary School in Toulouse, France and his colleagues infected six sheep with scrapie. After the animals died, the researchers analyzed their muscle tissue and found "small but consistent amounts" of the infectious prion in the creatures’ fore and hindlimbs. The scientists also examined a flock of sheep that had naturally succumbed to scrapie and detected prions in the muscles of two animals out of a dozen that were tested. One of these, which was 13.5 months old when it died, tested positive even though animals typically display clinical signs of scrapie only after 22 months of age. Fewer of the naturally-infected animals tested positive for prions in their muscles, suggesting that the infectious proteins spreads to muscles less efficiently in the wild than in the laboratory. In addition, the prions in the muscle tissues were 5,000 times less infective than were those recovered from brain tissue. Although this is the first observation of prions accumulating in the muscles of animals that enter the human food chain, the authors caution that the results cannot be extrapolated to BSE in cattle. In addition they note that "dietary exposure to scrapie is currently considered nonhazardous to humans." --Sarah Graham © 1996-2004 Scientific American, Inc

Keyword: Prions
Link ID: 5517 - Posted: 06.24.2010

Washington, D.C. – Researchers at Georgetown University have developed a novel technology to precisely measure the sensitivity of nerve fibers that wire up the brain during development. Through use of this technology, they discovered that these fibers, or axons, possess an incredible sensitivity to molecular guidance cues that direct the axon's route to its desired destination in the brain. Their findings are described in the June issue of Nature Neuroscience. Similar to connecting your PC, monitor, mouse and printer correctly to make all computer parts work, the developing brain needs a series of critical wiring connections to be made for it to function properly. But, unlike computers that come with a user and troubleshooting manual, nerve fibers called axons must follow molecular cues to find the right targets. Much work has been done to understand what molecules are involved in this process, called axonal guidance. However, no technology until now allowed researchers to create a controllable, stable gradient with which one could measure the sensitivity of axons to gradients, and how that sensitivity can impact and guide the development of connections in the brain.

Keyword: Development of the Brain
Link ID: 5516 - Posted: 06.24.2010

A combination therapy using transplanted cells plus two experimental drugs significantly improves function in paralyzed rats, a new study shows. The results suggest that a similar therapy may be useful in humans with spinal cord injury. The study was funded in part by the National Institute of Neurological Disorders and Stroke (NINDS), part of the National Institutes of Health, and appears in the June 2004 issue of Nature Medicine.* About 10,000 people in the United States suffer spinal cord injuries each year. Studies in animals during the past decade have shown that supporting cells from nerves outside the brain and spinal cord, called Schwann cells, can be used to make a "bridge" across the damaged spinal cord that encourages nerve fibers to regrow. Other research has suggested that a substance called cyclic AMP (cyclic adenosine monophosphate) can turn on growth factor genes in nerve cells, stimulating growth and helping to overcome signals that normally inhibit regeneration. This study is the first to try a combination of the two approaches in an animal model of spinal cord injury. In the new study, Mary Bartlett Bunge, Ph.D., Damien Pearse, Ph.D., and colleagues at the Miami Project to Cure Paralysis at the University of Miami School of Medicine, found that spinal cord injury triggers a loss of cAMP in the spinal cord and in some parts of the brain. They then transplanted Schwann cells into the spinal cords of rats in a way that bridged the damaged area. The researchers also gave the rats a form of cAMP and a drug called rolipram, which prevents cAMP from being broken down.

Keyword: Regeneration
Link ID: 5515 - Posted: 05.24.2004

Aspirin and other anti-inflammatory drugs given to newborn rats change their sexual behaviour later in life. The drugs interfere with the brain's sex-specific development, suggesting that they may also affect equivalent mechanisms in humans. In theory, mothers taking so-called non-steroidal anti-inflammatory drugs (NSAIDs) might pass on high levels to their baby via the placenta. The list of NSAIDs includes paracetamol (tylenol), aspirin and indomethacin (indocin), which prevents premature labour. But the researchers caution that, until similar effects have been found in people, expectant mothers should not change their use of medication. "I don't want to panic pregnant women," says Margaret McCarthy, who carried out the study at the University of Maryland, Baltimore, US, with her colleague Stuart Amateau. She says women are already advised to avoid taking unnecessary drugs. © Copyright Reed Business Information Ltd.

Keyword: Sexual Behavior
Link ID: 5514 - Posted: 06.24.2010

Suddenly the lights go out. You immediately think–circuit breaker. A few clicks in the fuse box and you're back in business. It's an easy enough challenge to overcome, right? Not for someone with schizophrenia. Available medications can help treat the more well-known symptoms of this brain ailment, like hallucinations and delusions. Imaginary voices diminish or vanish. Irrational fears of death plots by neighbors lose intensity or disappear. Many, however, remain persistently plagued by impaired thinking, learning, attention, and other cognitive deficits that damage their ability to solve everyday problems. After a power outage a person with schizophrenia will likely have no solution or an incorrect one. For example, they may inspect every light bulb on the floor individually. Cognitive impairments make it difficult to hold a job, maintain normal relationships, and live independently. But now thanks to years of study, the outlook for some 2 million Americans with schizophrenia may soon improve. New insights are helping scientists devise methods that target the cognitive side of the disorder. Strategies that already show promise in small human studies include techniques based on discoveries surrounding a brain cell component, termed the NMDA receptor. The advances are leading to: Copyright © 2004 Society for Neuroscience

Keyword: Schizophrenia
Link ID: 5513 - Posted: 06.24.2010

Italian scientists have shown dummy treatment can have a positive effect on the brain activity of patients with Parkinson's disease. In their study, this placebo therapy caused the part of the brain that is overactive in the disease to return to a more normal level of activity. These changes were closely related to improvement of symptoms. Professor Fabrizio Benedetti and his team at Turin University report their findings in Nature Neuroscience. The placebo effect is a complex phenomenon whereby a sham treatment can trigger a therapeutic effect if the subject believes that it is effective. Professor Benedetti and colleagues gave 11 patients with Parkinson's disease injections of drugs that temporarily relieved symptoms such as muscle stiffness and tremors. They then gave the same patients a placebo injection containing a harmless salt solution and no medication, but did not tell the patients that they had made the switch. Six of the patients responded to the placebo and had a decrease in arm rigidity. (C)BBC

Keyword: Parkinsons; Pain & Touch
Link ID: 5512 - Posted: 05.22.2004

Carl T. Hall, Chronicle Science Writer A Shasta County physician who once faced multiple counts of murder and other felonies as part of an alleged drug-dealing conspiracy was found not guilty late Tuesday of the remaining charges against him, ending a high- profile case seen as a test of the ability of doctors to treat patients with chronic pain. Dr. Frank B. Fisher, 50, was acquitted of charges that he had defrauded the state Medi-Cal system -- the only criminal charges that hadn't already been dropped -- by a Shasta County Superior Court jury after a two-week trial in Redding. The Fisher case is one of the first and most ambitious prosecutions in the country involving doctors accused of over-prescribing pain medications. Pain-control advocates view such prosecutions as a misguided war on legitimate drug use; authorities insist they have a problem only with physicians who knowingly dispense potent narcotics to people who don't really need them. Authorities shut down Fisher's Westwood Walk-In Clinic in February 1999 and took him and the pharmacists, Stephen and Madeline Miller, to jail in handcuffs. But Fisher, an East Bay native who earned his medical degree at Harvard University in 1981, never seemed to fit the mold of mass murderer and dope peddler. Fisher has maintained throughout his legal ordeal that he was singled out by prosecutors because he was one of the few doctors brave enough to prescribe high doses of narcotics, including the controversial prescription painkiller OxyContin, to low-income pain sufferers despite the scrutiny of drug- enforcement authorities. ©2004 San Francisco Chronicle

Keyword: Pain & Touch; Drug Abuse
Link ID: 5511 - Posted: 06.24.2010

By Noah Shachtman The military may have ways -- gruesome ways -- of making people talk, as the Abu Ghraib prison scandal has shown. But it still doesn't have a reliable method for figuring out whether those people are telling the truth or not. Nearly 75 years since the introduction of the polygraph, there's still nothing close to a foolproof lie detector. Traditional methods for catching a fibber have been battered by scientific study. And, despite endless waves of hype, the high-tech alternatives -- brain scans, thermal images and voice analysis -- have withered under scrutiny, or remain largely unproven. "Everybody would love to have a lie detector that works. But wanting it isn't going to make it happen," said Stephen Kosslyn, a Harvard University professor of psychology. "You can flip a coin, and get the same results," said Mike Ritz, a former Army interrogator who now trains people to withstand questioning. In a 2002 report, the National Academy of Sciences concluded that traditional polygraph screening was so flawed that it "presents a danger to national security." The group found that too many innocent people who took polygraphs were labeled guilty, and too many guilty people slid by undetected. © Copyright 2004, Lycos, Inc.

Keyword: Emotions; Stress
Link ID: 5510 - Posted: 06.24.2010

A tiny protein called ADDL could be the key to Alzheimer's By Tom Valeo Scientists have long suspected that the protein clumps and tangles identified by Alois Alzheimer in 1907 somehow cause the disease that bears his name, probably by killing neurons. Now some researchers are blaming a much smaller form of protein, one that apparently produces memory deficits merely by binding to neurons and disrupting their ability to transmit signals. The search has begun for an antibody that would destroy these tiny proteins--or ADDLs--thereby preventing the onset of Alzheimer's disease and possibly even reversing the early symptoms. The discovery of ADDLs explains glaring anomalies in the conventional thinking about Alzheimer's, which holds that fragments of amyloid precursor protein, produced by normal neurons, aggregate into sticky, insoluble plaques that damage neurons. The problem with this theory is that virtually every older person carries some amyloid plaque, but only a few develop Alzheimer's. Conversely, those with Alzheimer's often have relatively few plaques. Another proposed culprit is the presence of tangles of tau protein, which form inside neurons and coincide with the collapse of microtubules that support the cell body and transport nutrients. The tau tangles correlate much better with the disease but tend to appear later, suggesting that they are a consequence, not a cause. © 1996-2004 Scientific American, Inc.

Keyword: Alzheimers
Link ID: 5509 - Posted: 06.24.2010

PROVIDENCE, R.I. — Male bullfrogs communicate with other bullfrogs through calls made up of a series of croaks, some of which contain stutters, according to a new Brown University study which describes a pattern not previously identified in scientific literature. Researchers recorded 2,536 calls from 32 male bullfrogs in natural chorus and analyzed the number of croaks in each call and the number of stutters in each croak. It is known that the male bullfrog’s call attracts females for mating, maintains territorial boundaries with other males, and indicates that the frog is healthy and aggressive. “Some animals have evolved large, complex vocabularies to communicate, while others say a lot with very limited numbers of calls,” said Andrea Simmons, professor of psychology, who presented the findings at 75th meeting of the Acoustical Society of America Monday, May 24, 2004. “A fundamental question in the study of communication by sound is ‘how much information can a sender convey in a single sound’?”

Keyword: Animal Communication; Sexual Behavior
Link ID: 5508 - Posted: 06.24.2010

Amyloid fibers, those clumps of plaque-like proteins that clog up the brains of Alzheimer's patients, have perplexed scientists with their robust structures. In laboratory experiments, they are able to withstand extreme heat and cold and powerful detergents that cripple most other proteins. The fibers are in fact so tough that researchers now are exploring ways that they can be used in nanoscale industrial applications. While they are not necessarily the cause of Alzheimer's, they are associated with it and with many other neurological conditions, and researchers don't yet have a way to assail these resilient molecules. A study published this week in the advance online publication of the journal Science suggests that yeast may succeed where scientists have not. The research by a team at Whitehead Institute for Biomedical Research reports on a natural biological process by which yeast cells dismantle amyloid fibers. "These proteins are remarkably stable," says Susan Lindquist, director of Whitehead and lead researcher on the project. "This is the first time that anyone has found anything that can catalytically take apart an amyloid fiber."

Keyword: Alzheimers
Link ID: 5507 - Posted: 05.22.2004

John Travis As fans of the famous Westminster Dog Show will attest, dogs come in all shapes and sizes. The most thorough DNA analysis yet of purebred dogs suggests that canine breeds, typically defined by physical features and family history, can also be discerned genetically with great accuracy. "At a DNA level, breeds are a very real concept. Every poodle is more closely related to a poodle than it is to a dog of any other breed," says Elaine Ostrander of the Fred Hutchinson Cancer Research Center in Seattle. In the May 21 Science, she and her colleagues describe their analysis of DNA from 85 dog breeds. The new study is the latest spin—off from efforts to use man's best friend to investigate human health. Over the past few centuries, dog owners have created hundreds of breeds with strikingly different temperaments and physical characteristics. This inbreeding, however, has generated many breed-specific problems, such as deafness and osteoporosis, that also afflict people. Copyright ©2004 Science Service. All rights reserved.

Keyword: Genes & Behavior; Evolution
Link ID: 5506 - Posted: 06.24.2010

Almost 4000 Britons aged between 10 and 30 may be harbouring the prion proteins that cause the human form of mad cow disease. The new estimate comes from direct analyses of human biopsies, and is much higher than epidemiological projections of the likely number of deaths from variant Creutzfeldt-Jakob Disease (vCJD). The investigators discovered three infected tonsil or appendix samples from a total of 12,674 stored between 1995 and 1999. However, because so few positive samples were found, the projected total of 3808 can only be speculative. Furthermore, harbouring the prions may not necessarily lead to vCJD. "I don't think too much should be read into our findings, but they should be investigated further," says David Hilton, of the Derriford Hospital in Plymouth, UK, who led the study. He notes that only one of the three positive samples matched the usual pattern of prion accumulation seen in confirmed vCJD cases. © Copyright Reed Business Information Ltd.

Keyword: Prions
Link ID: 5505 - Posted: 06.24.2010

Music's ability to make us feel chirpy, sad, excited or just plain bored can be accurately predicted by only a few of its basic elements, an Australian scientist has discovered. "Among other things, loudness, tempo and pitch have a measurable impact on people's emotional response to music," says University of NSW music psychologist, Dr Emery Schubert. His is the first study of its kind to mathematically quantify the emotional impact of music. Sixty-seven subjects listened to four classical musical compositions while they moved a mouse over a computer screen to indicate the emotion they felt was being expressed musically. Their mouse movements indicated whether they found the music to be happy or sad and arousing or sleepy, on what Dr Schubert calls a "two-dimensional emotional space". These movements were automatically recorded by the computer once each second throughout the musical performance. "The results tell us that arousal is associated with a composition's loudness and to a lesser extent its tempo," says Dr Schubert, whose paper is to be published in the forthcoming issue of the journal, Music Perception. This was evident in the four compositions examined -- Slavonic Dance Opus No. 46 (Anton Dvorak), Concerto de Arunquez (Joaquin Rodrigo), Pizzicato Polka (Johan Strauss Jr and Josef Strauss) and 'Morning' (Edvard Grieg).

Keyword: Hearing; Emotions
Link ID: 5504 - Posted: 05.22.2004