Montréal, -- The group of Dr. Michel Cayouette, researcher at Institut de recherches cliniques de Montréal (IRCM), and Dr. Jonah Chan, collaborator at the University of Southern California, will publish in the next issue of the prestigious scientific journal Science, the results of their study that could have a major impact on the treatment of diseases such as multiple sclerosis, and peripheral neuropathies. At a basic level, our nervous system is like a collection of wires that transmit electrical signals encoding our thoughts, feelings, and actions, both conscious and unconscious. The connections in our brain are formed by neurons that extend to each other and to muscles long wires called axons. Just as an electrical wire needs insulation, our axons require an insulating sheath (myelin) that helps to propagate the electrical signal and maximize the efficiency and velocity of these signals in our brain and body. It is this property (myelination) that facilitates the long-distance communication in our nervous system across junctions called synapses, such that a thought can result in the movement of a finger or a toe. Diseases and injury that compromise the integrity of myelin such as multiple sclerosis, or peripheral neuropathies, have dramatic consequences like paralysis, uncoordinated movements, and neuropathic pain. The discovery reported in this study sheds light on the mechanisms that control how myelin is formed during development of the nerves. The article, which will be published in the November 3rd issue of Science, constitutes an important step forward in our understanding of the process of myelination, and opens the way to new research in this field.

Keyword: Multiple Sclerosis
Link ID: 9568 - Posted: 11.03.2006

By Constance Holden For a practice that's been around for thousands of years, scientists understand very little about what goes on when people "speak in tongues." Currently, glossolalia--as it's called--can be found in Pentecostal and Charismatic Christian sects, where those affected believe they are uttering a message directly from God. Now scientists say they have captured glossolalia on brain scans, which link decreased frontal lobe activity to a loss of self control. To conduct the study, psychiatrist Andrew Newberg of the University of Pennsylvania in Philadelphia and his colleagues recruited five African-American women who belong to a local Pentecostal congregation. All had been in the habit of speaking in tongues "almost on a daily basis" for the past 5 years, says Newberg. As a control activity, subjects stood and sang gospel songs with musical accompaniment, moving their arms and swaying. Then they were asked to repeat the behavior, but this time the researchers encouraged them to speak in tongues rather than sing. In each case, the scientists gave the subjects an intravenous injection of a radioactive tracer that provided, in effect, a freeze-frame of which brain areas were most active during the behavior, as indicated by increased blood flow. This was captured by then scanning the women's brains in a single photon emission computed tomography (SPECT) machine. © 2006 American Association for the Advancement of Science.

Keyword: Language
Link ID: 9567 - Posted: 06.24.2010

AFP — Promiscuous females are more likely to give birth to healthier babies than their monogamous sisters, Australian researchers investigating free love among the country's furry fauna have said. Scientists at the Australian National University said they had proven for the first time that frequent sex with multiple partners increased the survival rate of offspring in an animal species. The team's reproductive revelation comes after two years spent probing the sex life of the brown antechinus, a small mouse-sized carnivorous marsupial found in forests in southeastern Australia, which is related to the Tasmanian Devil. Team leader Diana Fisher said there were many theories for why some female animals had multiple sex partners — "whether it's trading sex for food and protection, dealing with infertile males or avoiding the negative effects of inbreeding in species that can't recognize their relatives." However her team is the first to convincingly demonstrate that promiscuity increased the odds of mating with males who had the strongest sperm, she said on Thursday. © 2006 Discovery Communications Inc.

Keyword: Sexual Behavior
Link ID: 9566 - Posted: 06.24.2010

Tracy Staedter, Discovery News — An implantable brain chip that serves as an artificial connection between nerve cells could one day help rehabilitate lost muscle movement in patients who have suffered brain injuries, stroke or paralysis. "We found that when we put in these connections for long periods of time, we induce a reorganization of wiring in the brain," said Andrew Jackson, a senior research fellow in physiology and biophysics at the University of Washington in Seattle. Jackson and his team reported their findings on the so-called Neurochip in a recent issue of the journal Nature. Reorganizing the brain's wiring can be a long and frustrating process for people who have lost muscle use after an injury or stroke. Typically, they must spend many hours doing physical exercises that encourage brain signals to find new pathways through healthy tissue. But those new pathways are not always complete, which can translate into limited recovery of movement. Or a given pathway may never form at all, which means the person has to find a completely new way to perform a task. © 2006 Discovery Communications Inc.

Keyword: Robotics
Link ID: 9565 - Posted: 06.24.2010

Helen Pearson It has long been held that the ideal human body temperature is a snug 37 degrees Celsius. Our bodies stick rigidly to it when healthy, and high fevers can be deadly. But a new study suggests that 36.5 °C might be even better. Mice cooled by half a degree below normal had a life expectancy 20% longer, or the equivalent of 7-8 additional human years. Researchers have known for decades that a diet containing a third less calories than usual extends the lifetime of mice and other mammals by up to 40% and drops their body temperature by half a degree or more. It was not known whether the cooler temperature helps stave off ageing or is simply a by-product of the low-calorie diet. And this is virtually impossible to test, because mammals maintain the same temperature regardless of the surrounding clime. Conti's team managed to cool down mice using genetic engineering. They used a gene called uncoupling protein 2, which diverts the cells' mitochondria from their usual task of making chemical energy, and instead prompts them to release energy as heat. They inserted this gene into a group of brain cells in the animals' hypothalamus and near to the region that senses and controls body temperature, much like a thermostat. The gene effectively heated up the thermostat and, as a result, tricked the rest of the body into cooling down by 0.3 to 0.5 °C. ©2006 Nature Publishing Group

Keyword: Obesity
Link ID: 9564 - Posted: 06.24.2010

A reexamination of ancient human bones from Romania reveals more evidence that humans and Neandertals interbred. Erik Trinkaus, Ph.D., Washington University Mary Tileston Hemenway Professor in Arts & Sciences, and colleagues radiocarbon-dated and analyzed the shapes of human bones from Romania's Pe?tera Muierii (Cave of the Old Woman). The fossils, discovered in 1952, add to the small number of early modern human remains from Europe known to be more than 28,000 years old. Results were published in the current issue of the Proceedings of the National Academy of Science. The team found that the fossils were 30,000 years old and principally have the diagnostic skeletal features of modern humans. They also found that the remains had other features known, among potential ancestors, primarily among the preceding Neandertals, providing more evidence there was mixing of humans and Neandertals as modern humans dispersed across Europe about 35,000 years ago. Their analysis of one skeleton's shoulder blade also shows that these humans did not have the full set of anatomical adaptations for throwing projectiles, like spears, during hunting.

Keyword: Evolution
Link ID: 9563 - Posted: 11.03.2006

ANN ARBOR, Mich.---The unassuming C. elegans nematode worm, a 1-millimeter workhorse of the genetics lab, is quite similar to human beings in its genetic susceptibility to nicotine dependence, according to University of Michigan researchers. This finding should allow researchers to better understand how nicotine dependence works, and perhaps devise new ways to block the craving that keeps humans smoking cigarettes. Nicotine is the addictive substance in tobacco. Dependence on nicotine drives many of the most preventable causes of death in the U.S. and is a worldwide health problem. A team led by X.Z. Shawn Xu, assistant research professor at the Life Sciences Institute and assistant professor of physiology at U-M Medical School, has completed a series of experiments which establish that C. elegans can get hooked on nicotine. Like humans, the nicotine-sensitive worms showed acute responses to nicotine exposure, as well as tolerance, sensitization and withdrawal. "It turns out that worms exhibited behavioral responses to nicotine that parallel those observed in mammals," said Xu, whose name is pronounced Shoo. "But it is much easier to identify novel functions of a gene in worms." Xu and his team found that the genes known to underlie nicotine dependence in mammals are also present in the worms. Having established worms as a model, the Xu team then tried to identify new genes important for nicotine dependence.

Keyword: Drug Abuse
Link ID: 9562 - Posted: 11.03.2006

Roxanne Khamsi Monkeys that are abused as infants develop a specific brain change that makes them more likely to mistreat their own offspring, a new study shows. The findings may help explain why child abuse in humans often perpetuates from one generation to the next, the researchers say. Dario Maestripieri at the University of Chicago in Illinois, US, and colleagues found that baby rhesus monkeys that endured high rates of maternal rejection and mild abuse in their first month of life produced less of the brain chemical serotonin. Low levels of serotonin are associated with anxiety and depression and impulsive aggression in both humans and monkeys. The team followed a group of newborn rhesus monkeys with mothers that abused and rejected them. They also studied eight newborn monkeys taken from their birth mothers and placed with abusive ones instead. Analysis of the monkeys’ brain fluid revealed that those reared by abusive mothers or abusive foster mothers had 10% to 20% less serotonin than monkeys who had grown up without maternal abuse. This supports the idea that the drop in serotonin results from mistreatment, rather than a genetic predisposition, says Maestripieri. © Copyright Reed Business Information Ltd

Keyword: Aggression; Stress
Link ID: 9561 - Posted: 06.24.2010

By Rob Stein A substance found in red wine protected mice from the ill effects of obesity and extended their life spans, raising the tantalizing prospect that the compound could do the same for humans and may also help people live longer, healthier lives, researchers reported yesterday. The substance, called resveratrol, enabled mice that were fed a high-calorie, high-fat diet to live normal, active lives despite becoming obese -- the first time any compound has been shown to do that. Tests found that the agent activated a host of genes that protect against aging, essentially neutralizing the adverse effects of the bad diet on the animals' health and longevity. Although much more work is needed to explore the benefits and safety of the substance, which is sold over the counter as a nutritional supplement, the findings could lead to the long-sought goal of extending the healthy human life span, experts said. Preliminary tests in people are underway. "We've been looking for something like this for the last 100,000 years, and maybe it's right around the corner -- a molecule that could be taken in a single pill to delay the diseases of aging and keep you healthier as you grow old," said David A. Sinclair, a Harvard Medical School molecular biologist who led the study. "The potential impact would be huge." © 2006 The Washington Post Company

Keyword: Obesity
Link ID: 9560 - Posted: 06.24.2010

Emma Young Have sex and die: that's the lot of a shrew-like marsupial that can't afford to waste time picking out the ideal mate but seems to produce great offspring all the same. It looks like the trick might be down to some high-performance sperm. Antechinus stuartii is a small Australian marsupial with a bizarre sex life. Males gather in a nest, wait for females to turn up and then attempt to mate with as many as possible in what for both sexes is a once-in-a-lifetime sexual orgy. Two weeks later, the males' immune systems fail and they die, while the females go on to produce what is usually their one and only litter before dying a few months later. When Diana Fisher of the Australian National University in Canberra and colleagues took wild animals and allowed females to mate either once with each of three males, or three times with just one male, they found females with multiple mates had three times as many offspring that survived till weaning. Promiscuous these animals may be, but that doesn't mean anything goes genetically speaking. Paternity tests and follow-up experiments revealed that some males sired far more surviving offspring than others. That would make sense, say the researchers, if better-quality males also produce sperm that is able to outcompete the sperm of other males. If so, females do not need to pick out the best males: instead, they can mate with multiple partners and let the males' sperm fight it out (Nature, vol 44, p 89). © Copyright Reed Business Information Ltd

Keyword: Sexual Behavior
Link ID: 9559 - Posted: 06.24.2010

People in western countries tend to have more sexual partners than those in the developing world, a study says. Monogamy is dominant across the world, but multiple partners are more common in rich countries, according to the study published in the Lancet. This was despite developing countries having higher rates of sexually transmitted infections and HIV. London School of Hygiene and Tropical Medicine researchers gathered data from 59 countries for the study. They said factors such as poverty and mobility had more of a role in sexually transmitted infections than promiscuity had. But the team added that the findings showed teenagers were not having sex earlier, contrary to popular beliefs. The study said there had been no universal trend towards earlier sexual intercourse over the past three decades. Almost everywhere, sexual activity began for most men and women between 15 and 19 years of age, with men tending to start earlier. In the UK the average age for men was 16.5 and for women 17.5. Researchers said most people reported only having one sexual partner in the last year. However, those reporting multiple partners were much higher in developed countries - up to a third of under 25s in some areas - whereas only a small percentage in Africa reported the same. And among singletons, westerners were more sexually active as well. Two thirds of men and women without a partner in African countries reported they had had sex recently, compared to three quarters of those in developed countries. (C)BBC

Keyword: Sexual Behavior
Link ID: 9558 - Posted: 11.01.2006

By BENEDICT CAREY Infants who die in their sleep of no apparent cause often have subtle defects in an area of the brain that regulates breathing, heart rate and arousal, doctors are reporting today. Multiple Serotonergic Brainstem Abnormalities in Sudden Infant Death Syndrome (JAMA)The findings, appearing in The Journal of the American Medical Association, provide the strongest evidence yet that a physical abnormality, probably genetic in origin, can help explain what until recently was a matter of speculation for scientists and deep anxiety for new parents: sudden infant death syndrome, or SIDS. More than 2,000 babies a year, about 7 of every 10,000 born in this country, die of SIDS in the first months of their life. Researchers have found that many of the deaths occurred while the babies, most of them boys, were sleeping on their stomachs, often on soft bedding or in a bed with someone else. A public education campaign teaching parents to place infants on their back on a firm mattress has reduced the SIDS rate in recent years. Suspicions of child abuse also cloud many sudden infant deaths, though recent research suggests that abuse is responsible in less than 5 percent of such cases. The new study confirms that a far more important cause is defects in how neurons process serotonin, a brain chemical associated with mood and arousal. Experts said the findings could help doctors develop a diagnostic test for SIDS risk and possibly preventive treatments. Copyright 2006 The New York Times Company

Keyword: Sleep; Development of the Brain
Link ID: 9557 - Posted: 11.01.2006

By Andrew Stern CHICAGO (Reuters) - Stroke victims forced to use a weakened or partially paralyzed arm by having their working arm or hand restrained in a sling or mitt recover more quickly, researchers said on Tuesday. In a study of 222 patients, those who underwent "constraint-induced" therapy within three to nine months of their strokes were more capable of performing an array of tasks in follow-up tests than those who were not forced to use their affected arm. Participants in the study were instructed to wear the restraint -- either a sling or a cumbersome mitt -- during waking hours for two weeks. They also underwent physical therapy for several hours on weekdays, during which they wore the restraint. Most had suffered an ischemic stroke, the most common type where blood flow is temporarily blocked to part of the brain. In previous studies, images taken of patients' brains undergoing the constraint therapy showed it stimulated areas that control the stroke-affected arm. The constrained patients scored much higher on physical tests up to a year later when compared with stroke patients who underwent customary rehabilitation. Usually patients undergo some physical therapy, which can be followed by drug treatment and instructions to perform exercises. © 1996-2006 Scientific American, Inc.

Keyword: Stroke
Link ID: 9556 - Posted: 06.24.2010

By R. Aidan Martin and Anne Martin It’s twenty past seven on a winter morning. Our research vessel drifts off Seal Island, South Africa. A lone Cape fur seal pup porpoises through the gently rolling swells toward the island. Suddenly, a ton of white shark launches from the water like a Polaris missile, the little seal clamped between its teeth. Framed against purple clouds washed with the orange light of breaking dawn, the shark clears the surface by an astonishing six feet. It hangs, silhouetted in the chill air for what seems an impossibly long time before it falls back into the sea, splashing thunderous spray beneath a gathering mob of seabirds. We and our crew of five student volunteers watch breathlessly as the drama unfolds. Now mortally wounded and lying on its side at the surface, the seal raises its head and weakly wags its left foreflipper. The shark, an eleven-and-a-half-foot male we call Sneaky, circles back unhurriedly and seizes the hapless pup again. He carries it underwater, shaking his head violently from side to side, an action that maximizes the cutting efficiency of his saw-edged teeth. An ominous blush stains the water and the oily, coppery smell of the wounded seal prickles our nostrils. The seal carcass floats to the surface while gulls and other seabirds compete vigorously for its entrails, squawking avian obscenities at one another. Sneaky returns to his meal, and another white shark rises from below—a thirteen-foot male we call Couz. For white sharks (also known as great whites), socializing trumps dining. Sneaky turns his attention to Couz. Is he friend or foe? Of higher or lower rank? © Natural History Magazine, Inc., 2006

Keyword: Aggression
Link ID: 9555 - Posted: 06.24.2010

In the largest, most comprehensive study of its kind to date, researchers supported by the National Institutes of Health (NIH) showed clinical improvements out to one year when stroke survivors who had lost function in one arm were given a unique, two-week rehabilitation regimen. Steven Wolf, Ph.D., Professor of Rehabilitation Medicine at Emory University, led a multi-center team that tested the effects of constraint-induced movement therapy (CIMT) in 222 patients. The study, which is featured in the November 1, 2006 issue of The Journal of the American Medical Association,* was funded by the National Institute of Child Health and Human Development (NICHD) and the National Institute of Neurological Disorders and Stroke (NINDS). “This study provides the strongest evidence to date that constraint induced movement therapy can help stroke patients regain lost arm function,” said NIH Director Elias A. Zerhouni, M.D. “This is welcome news for stroke patients and those who care about them.” Each year, more than 700,000 Americans are hospitalized for stroke, an interruption of blood flow in the brain. Up to 85 percent of survivors have weakness on one side of their body. CIMT involves training the weakened hand and arm through repetitive exercises, while restraining the unaffected hand and arm with a mitt like a boxing glove. The theory behind the hand restraint is that it forces the wearer to use the affected hand and arm.

Keyword: Stroke
Link ID: 9554 - Posted: 06.24.2010

By Amy Bowles Reyer, Ph.D. Try to imagine that your loved one has become romantically interested in someone else. And then try to envision which scenario would bother you more: (a) learning that your partner has fallen in love with that person or (b) discovering that your partner has had meaningless sex with that person. Obviously, both situations are painful to think about, but chances are one of these bothers you more than the other. And just as likely, your gender has a lot to do with which one causes you the most anguish. Both men and women experience jealousy and according to David Buss, Ph.D., professor of evolutionary psychology at the University of Texas, this is both healthy and necessary to the fitness of a faithful relationship. In The Dangerous Passion: Why Jealousy Is As Necessary As Love and Sex," Buss describes his survey of women and men in the United States, the Netherlands, Germany, Japan, Korea and Zimbabwe. The majority of women interviewed were troubled more about a partner's emotional infidelity, while the men were most upset about sexual transgressions. The differing grounds for jealousy between men and women reveal highly adaptive responses for the human species. Since fertilization takes place inside the female body, it is difficult to determine paternity with any real certainty. The ancestral man was therefore unable to know whether he was, in fact, the real father of his children. © 2006 Discovery Communications Inc.

Keyword: Sexual Behavior
Link ID: 9553 - Posted: 06.24.2010

Linda Geddes Structural abnormalities in a baby’s brainstem may lie behind about half the cases of sudden infant death syndrome (SIDS). Hannah Kinney and David Paterson at the Children’s Hospital in Boston, Massachusetts, US, examined the brains of 31 infants who had died of SIDS – also known as cot-death – and compared them to the brains of 10 infants who died of other causes. They found abnormalities in the medulla – the part of the brainstem which regulates breathing, blood pressure, body heat and arousal. SIDS babies had more of the neurons that release the brain chemical serotonin, but fewer receptors for serotonin. Kinney has previously recorded low numbers of serotonin receptors in around a half of SIDS babies. And studies in mice have shown that “pacemaker” cells in the medulla – which prompt gasping and recovery – do not fire when serotonin is taken away (see Infant death link to low serotonin). “It might be that a defect in the medulla’s serotonin system is inhibiting a baby’s ability to gasp,” says Paterson. Only further tests will establish whether pacemaker cells are simply not responding to serotonin, or whether the ability of neurons to release it is turned off, he says. The study also found fewer serotonin receptors in male SIDS cases compared with females, which could help explain why SIDS occurs twice as often in male as female babies. No such difference was found in the number of serotonin-releasing neurons, however. © Copyright Reed Business Information Ltd

Keyword: Sleep; Development of the Brain
Link ID: 9552 - Posted: 06.24.2010

By Sandra G. Boodman The programs have catchy names like "Food, Mood and Attitude" and "Full of Ourselves" as well as an ambitious goal: to prevent adolescent eating disorders, which tend to be chronic, difficult to treat and sometimes fatal. But do they work? In the case of one such program -- "Student Bodies," developed by researchers at Stanford University -- a recently published study suggests that the answer is yes. Stanford researchers, who followed 480 female California college students for up to two years, report that the eight-week Internet-based program reduced the development of eating disorders in women at high risk. "This study shows that innovative intervention can work," said Thomas Insel, director of the National Insitute of Mental Health, which funded the study; its findings appeared in the August issue of the Archives of General Psychiatry. Prevention programs for eating disorders have proliferated in the past decade, in part because of the high cost and low success rate of treatment programs. The disorders include a constellation of problems, including anorexia, a pathological fear of gaining weight marked by self-starvation. Anorexia has the highest mortality rate of any psychiatric illness: About 10 percent of patients hospitalized for treatment ultimately die of the disorder. © 2006 The Washington Post Company

Keyword: Anorexia & Bulimia
Link ID: 9551 - Posted: 06.24.2010

By MICHAEL MASON How depressing, how utterly unjust, to be the one in your social circle who is aging least gracefully. In a laboratory at the Wisconsin National Primate Research Center, Matthias is learning about time’s caprice the hard way. At 28, getting on for a rhesus monkey, Matthias is losing his hair, lugging a paunch and getting a face full of wrinkles. Yet in the cage next to his, gleefully hooting at strangers, one of Matthias’s lab mates, Rudy, is the picture of monkey vitality, although he is slightly older. Thin and feisty, Rudy stops grooming his smooth coat just long enough to pirouette toward a proffered piece of fruit. Tempted with the same treat, Matthias rises wearily and extends a frail hand. “You can really see the difference,” said Dr. Ricki Colman, an associate scientist at the center who cares for the animals. What a visitor cannot see may be even more interesting. As a result of a simple lifestyle intervention, Rudy and primates like him seem poised to live very long, very vital lives. Copyright 2006 The New York Times Company

Keyword: Alzheimers; Obesity
Link ID: 9550 - Posted: 06.24.2010

By NICHOLAS WADE Who doesn’t know the difference between right and wrong? Yet that essential knowledge, generally assumed to come from parental teaching or religious or legal instruction, could turn out to have a quite different origin. Primatologists like Frans de Waal have long argued that the roots of human morality are evident in social animals like apes and monkeys. The animals’ feelings of empathy and expectations of reciprocity are essential behaviors for mammalian group living and can be regarded as a counterpart of human morality. Marc D. Hauser, a Harvard biologist, has built on this idea to propose that people are born with a moral grammar wired into their neural circuits by evolution. In a new book, “Moral Minds” (HarperCollins 2006), he argues that the grammar generates instant moral judgments which, in part because of the quick decisions that must be made in life-or-death situations, are inaccessible to the conscious mind. People are generally unaware of this process because the mind is adept at coming up with plausible rationalizations for why it arrived at a decision generated subconsciously. Dr. Hauser presents his argument as a hypothesis to be proved, not as an established fact. But it is an idea that he roots in solid ground, including his own and others’ work with primates and in empirical results derived by moral philosophers. Copyright 2006 The New York Times Company

Keyword: Evolution; Emotions
Link ID: 9549 - Posted: 06.24.2010