For the first time, researchers have linked mutations in a gene that regulates how potassium enters cells to a neurodegenerative disease and to another disorder that causes mental retardation and coordination problems. The findings may lead to new ways of treating a broad range of disorders, including Alzheimer's and Parkinson's diseases. The study was funded in part by the National Institutes of Health's National Institute of Neurological Disorders and Stroke (NINDS). "This type of gene has never before been linked to nerve cell death," says Stefan Pulst, M.D., of Cedars-Sinai Medical Center at the University of California, Los Angeles, who led the new study. The report will appear in the February 26, 2006, advance online publication of Nature Genetics.* In the study, the researchers looked for the gene that caused a neurodegenerative movement disorder called spinocerebellar ataxia in a Filipino family. This disorder typically appears in adulthood and causes loss of neurons in the brain's cerebellum, resulting in progressive loss of coordination (ataxia). Dr. Pulst and his colleagues traced the disease in this family to mutations in a gene called KCNC3. The gene codes for one of the proteins that form potassium channels – pore-like openings in the cell membrane that control the flow of potassium ions into the cell. The researchers found a different KCNC3 mutation in a previously identified French family with a disease called spinocerebellar ataxia type 13, which causes childhood-onset ataxia, cerebellar degeneration, and mild mental retardation.

Keyword: Development of the Brain; Movement Disorders
Link ID: 8589 - Posted: 06.24.2010

The question of why organisms have sex may seem trivially easy – any mortified kid who's sat through a birds-and-bees lecture knows that it's to reproduce. But biologists have for many decades struggled to puzzle out an ironic quirk of sexual reproduction: since males cannot produce offspring, sexual species have only half the raw reproductive capacity of asexual ones, in which every individual can crank out the young'uns. Despite decades of research, biologists still have not pinned down the theory of how sexual reproduction – which seems to work out okay in the real world – makes up for this huge cost. A study of the tiny water flea published in Science last week provides what might be the first direct evidence of why sex is so good – on a species level. The water flea was practically born for such research because it lives both in sexual groups and in asexual ones, which branched off from sexual groups at various times in the past. Two Indiana University biologists, Susanne Paland and Michael Lynch, looked at the genetic signatures of various flea populations from Illinois to Nova Scotia to see how the sexual and asexual groups differed. Their research showed that after the asexual groups stopped reproducing sexually, they all began picking up negative mutations – mutations that hurt their owners in the natural-selection game – faster than their sexual counterparts. So although the loner fleas could reproduce faster, over time, their gene pools became less desirable than ones who never broke up with sex. © 2005 Discover Media LLC.

Keyword: Sexual Behavior; Evolution
Link ID: 8588 - Posted: 06.24.2010

Anabolic steroids not only make teens more aggressive, but may keep them that way into young adulthood. The effect ultimately wears off but there may be other, lasting consequences for the developing brain. These findings, published in February's Behavioral Neuroscience, also showed that aggression rose and fell in synch with neurotransmitter levels in the brain's aggression control region. Behavioral Neuroscience is published by the American Psychological Association (APA). Neuroscientists are deeply concerned about rising adolescent abuse of anabolic-androgenic steroids (AASs), given the National Institute on Drug Abuse's estimate that nearly half a million eighth- and 10th-grade students abuse AASs each year. Not only do steroids set kids up for heavier use of steroids and other drugs later in life, but long-term users can suffer from mood swings, hallucinations and paranoia; liver damage; high blood pressure; as well as increased risk of heart disease, stroke and some types of cancer. Withdrawal often brings depression, and recent research suggests that some AASs may even be habit-forming. Overseen by Richard Melloni Jr., PhD, of Northeastern University in Boston, the current study of 76 adolescent hamsters compared how individual hamsters behaved when another hamster was put into their cages. Normally mild-mannered hamsters still defend their turf, learning aggression during puberty by play-fighting, much like humans. Their roughhousing normally includes wrestling and nibbling – pretty tame stuff.

Keyword: Aggression; Hormones & Behavior
Link ID: 8587 - Posted: 06.24.2010

Michael Hopkin Ever struggled to recall something you knew you ought to remember? Part of the problem might be that your brain just wasn't ready to store the memory in the first place. Neuroscientists have discovered that how successfully you form memories depends on your frame of mind not just during and after the event in question, but also before it. "People didn't realize that what the brain does before something happens influences the memory of that event," says Leun Otten of University College London, UK, who led the research. "They looked just at the response." But it turns out that if your brain is 'primed' to receive information, you will have less trouble recalling it later. By scanning the brain during these memory tests, the researchers found they could see this priming in action. By watching brain activity they could predict whether the participant would remember a subsequent event, before the event itself had happened. ©2006 Nature Publishing Group

Keyword: Learning & Memory
Link ID: 8586 - Posted: 06.24.2010

'Staggeringly stronger' immune response may be why socially isolated women seem to be less susceptible to illness and death than isolated men. Gender difference in immune inflammatory response may be related to demands of motherhood. Socially isolated female rats that experience stress generate a "staggeringly stronger" response to an immune challenge than similarly isolated and stressed males, according to a new study. The difference in the female rats' responses may stem from the demands of motherhood, researchers speculate in the study "Social isolation and the inflammatory response: sex differences in the enduring effects of a prior stressor" by Gretchen L. Hermes, Anthony Montag and Martha K. McClintock of the University of Chicago, and Louis Rosenthal of the University of Wisconsin, Madison. The study appears in the February issue of the American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, published by the American Physiological Society. The study reinforces a growing body of evidence on health disparities between men and women and may shed light on why socially isolated men are more vulnerable to disease and death than isolated women, Hermes said.

Keyword: Stress; Sexual Behavior
Link ID: 8585 - Posted: 02.27.2006

Women are more likely to prefer the deep tones of Barry White to the higher pitched vocals of James Blunt when looking for a mate, scientists believe. Research at St Andrews University found women prefer men with masculine voices, especially during their fertile phase. They like men with dominant voices as they are thought to indicate long-term health and higher reproductive success. It follows research findings that women during their fertile phase prefer men with more masculine faces. However, the researchers found that when not fertile, women were more likely to be attracted to a more feminine voice signalling a more caring man, more likely to invest in a long-term relationship. Researchers said only attractive, feminine women did not vary preference over the menstrual cycle, possibly because they may find it easier to establish a long-term relationship with men with deep voices, indicative of high levels of testosterone. Dr David Feinberg, St Andrews University researcher, said: "We already know male vocal attractiveness is highly related to masculinity and men with attractive voices have more mating success than men with unattractive voices. "We asked women to assess attractiveness and dominance of voices across the menstrual cycle and predicted that preference for masculinity in men's voices would be stronger when conception risk is high. Women's preferences for masculine voices change over the menstrual cycle: women prefer masculine voices more when fertile." (C)BBC

Keyword: Sexual Behavior; Hearing
Link ID: 8584 - Posted: 02.25.2006

By Shankar Vedantam More than 7 million Americans are estimated to have misused stimulant drugs meant to treat attention-deficit hyperactivity disorder, and substantial numbers of teenagers and young adults appear to show signs of addiction, according to a comprehensive national analysis tracking such abuse. The statistics are striking because many young people recreationally using these drugs are seeking to boost academic and professional performance, doctors say. Although the drugs may allow people to stay awake longer and finish work faster, scientists who published a new study concluded that about 1.6 million teenagers and young adults had misused these stimulants during a 12-month period and that 75,000 showed signs of addiction. The study published online this month in the journal Drug and Alcohol Dependence culled data from a 2002 national survey of about 67,000 households. The data paint a concrete and sobering picture of what many experts have worried about for years, and present ethical and medical challenges for a country where mental performance is highly valued and where the number of prescriptions for these drugs has doubled every five years, said Nora Volkow, director of the National Institute on Drug Abuse. © 2006 The Washington Post Company

Keyword: ADHD; Drug Abuse
Link ID: 8583 - Posted: 06.24.2010

Christen Brownlee Anyone who frequents the local gym has probably noticed a cyclical pattern to attendance. Workout kings and queens exercise religiously throughout the year, but as swimsuit season approaches, a rash of new faces flocks to the facility. Every treadmill is taken, each elliptical machine is engaged, and without fail, there's a waiting line for a weight machine. While exercise may be the path to looking great in a two-piece, everyone knows that it's also healthy for the body. It strengthens the heart and lungs, shores up thinning bones, and wards off a host of evils, including diabetes, heart disease, and stroke. But what these newly inaugurated gym rats probably don't know is that besides buffing up their bodies for summer, they're also buffing up their brains. New research suggests that physical exercise encourages healthy brains to function at their optimum levels. Fitness prompts nerve cells to multiply, strengthens their connections, and protects them from harm. Benefits seem to extend to brains and nerves that are diseased or damaged. These findings could suggest new treatments for people with Alzheimer's disease, Parkinson's disease, and spinal cord injuries. Copyright ©2006 Science Service.

Keyword: Development of the Brain
Link ID: 8582 - Posted: 06.24.2010

Bruce Bower A 260,000-year-old partial skeleton excavated in northwestern China 22 years ago represents our largest known female ancestor, according to a new analysis of the individual's extensive remains. This ancient woman puts a modern twist on Stone Age human evolution, say Karen R. Rosenberg of the University of Delaware in Newark, Lü Zuné of Peking University in Beijing, and Chris B. Ruff of Johns Hopkins University School of Medicine in Baltimore. The fossil individual's large size and the apparent adaptation of her body to cold conditions are "consistent with the idea that patterns of human anatomical variation that we see today have deep evolutionary roots," Rosenberg asserts. Although the woman belonged to the Homo genus, her species is uncertain. Now known as the Jinniushan specimen, she stood roughly 5 feet, 5-1/2 inches tall and tipped the scales at 173 pounds, the three anthropologists estimate. The only Stone Age Homo woman known to have approached that size weighed an estimated 163 pounds. Her partial skeleton came from a 100,000-year-old Neandertal site in France. The Jinniushan specimen's size reflects her membership in a population that, as an adaptation for retaining heat in a cold climate, evolved large, broad bodies with short limbs, a shape similar to that of near-polar populations today, the scientists propose in an upcoming Proceedings of the National Academy of Sciences. Copyright ©2006 Science Service.

Keyword: Evolution
Link ID: 8581 - Posted: 06.24.2010

When Rice University alumna Brianna Conrey was in third grade in Stillwater, Okla., she misspelled "pen" on a test because her teacher unknowingly pronounced it "pin." At the time, Conrey never would have guessed that she would write a senior thesis in college about the brain activity that takes place in people who don't distinguish between similar-sounding words like "pin" and "pen." Nor would she have guessed that her thesis would get published several years later in the journal Brain and Language. While working on a B.A. in linguistics at Rice, Conrey wanted to study the variation in spoken American English in certain regions of the U.S. "I lived in a lot of different areas of the country as a kid and was exposed to many different ways of talking, so this topic was really fascinating," Conrey said. "We know from sociolinguistics – the study of language variation and change – that a great deal of phonetic variation occurs even within a single language." She cited as an example a language variation known as a "vowel merger," in which two vowels with different pronunciation in one dialect of a language are merged, or not distinguished in pronunciation, in another dialect. The pin/pen merger, in which "i" and "e" are both pronounced like "i" before nasal sounds like "n" and "m" but not in other contexts, is often heard in Southern states and Texas, where a merged-dialect speaker might sound like they're pronouncing both "pin" and "pen" as "pin" to an unmerged-dialect speaker. The merged-dialect speaker is unlikely to be aware of the lack of distinction between the two sounds.

Keyword: Language
Link ID: 8580 - Posted: 06.24.2010

Children who are anxious or depressed are more likely to use ecstasy when they are older, a study has suggested. Dutch scientists studied 1,500 children with an average age of nine, in 1983. When they went back 14 years later, those who had shown signs of anxiety or depression as children were found to be at an increased risk of using the drug. The research, published in the British Medical Journal, said depressed people may take the drug to feel better, but warns it is likely to make them worse. For some time, scientists have been aware that using ecstasy is associated with emotional health problems, such as depression, psychotic symptoms, and anxiety disorders. But it was not clear whether emotional problems were caused by using ecstasy, or if they led to ecstasy use. The team of researchers from the Erasmus Medical Centre in Rotterdam looked at the 1,580 children as part of a long-term population study. All were aged between four and 17 when they were first assessed in 1983 - before ecstasy began to be used as a recreational drug in the Netherlands. The researchers used scientific checklists to assess if the children had any of 120 emotional or behaviour problems, such as being withdrawn, having attention problems or being aggressive. The study participants were followed up in 1997, when they were aged between 18 to 33. It was found that individuals who had shown signs of anxiety and depression as children in 1983 showed an increased risk of starting to use ecstasy. (C)BBC

Keyword: Depression; Drug Abuse
Link ID: 8579 - Posted: 02.24.2006

by JOHN LANCHESTER It is the year 100,000 B.C., and two hunter-gatherers are out hunter-gathering. Let’s call them Ig and Og. Ig comes across a new kind of bush, with bright-red berries. He is hungry, as most hunter-gatherers are most of the time, and the berries look pretty, so he pops a handful in his mouth. Og merely puts some berries in his goatskin bag. A little later, they come to a cave. It looks spooky and Og doesn’t want to go in, but Ig pushes on ahead and has a look around. There’s nothing there except a few bones. On the way home, an unfamiliar rustling in the undergrowth puts Og in a panic, and he freezes, but Ig figures that whatever is rustling probably isn’t any bigger and uglier than he is, so he blunders on, and whatever was doing the rustling scuttles off into the undergrowth. The next morning, Og finally tries the berries, and they do indeed taste O.K. He decides to go back and collect some more. Now, Ig is clearly a lot more fun than Og. But Og is much more likely to pass on his genes to the next generation of hunter-gatherers. The downside to Ig’s fearlessness is the risk of sudden death. One day, the berries will be poisonous, the bear that lives in the cave will be at home, and the rustling will be a snake or a tiger or some other vertebrate whose bite can turn septic. Ig needs only to make one mistake. From the Darwinian point of view, Og is the man to bet on. He is cautious and prone to anxiety, and these are highly adaptive traits when it comes to survival. Copyright © CondéNet 2006.

Keyword: Emotions
Link ID: 8578 - Posted: 06.24.2010

Everyone is familiar with the stereotype of the woman temporarily turned insane by her menstrual cycle. One minute she's sobbing uncontrollably over a commercial for baby food, the next she's screaming in fury at her ten-year-old for spilling milk on the kitchen counter. Meanwhile, her husband tries to stay out of the way by watching television in the living room, sighing under his breath, "just a few more days… ." Although this picture is a dramatic exaggeration often played up in pop culture, PMS is a real disorder that neuroscientist David Silbersweig at the Weill Medical College of Cornell University estimates affects 75 percent of women, albeit with varying degrees of intensity. For the most part, women experience mild variations of what Kimberly Echeverria of Brooklyn, NY describes, "I get emotional. I'll get mad, I'll get sad, I just get emotional," she says. But for others, the problems can be more serious. Pam Purewall from London, England says, "I get very frazzled, my mind goes all wooshy, I can't concentrate. That's the time when I have the most car accidents." The other 25 percent of women, though, somehow manage to avoid the notorious monthly mood swings entirely. How some women can be so affected by PMS, while others stay level-headed, remains a mystery. But as reported on Discover.com, Silbersweig may be on the road to an answer. His research team set up MRI brain scanners to take a look at what happened in the brains of 12 women who are part of the lucky minority that doesn't get PMS. "We wanted to understand what goes on in the brain across the menstrual cycle in women who don't have fluctuation and then be able, in the future, to compare that with women who do experience the fluctuations," he explains. © ScienCentral, 2000-2006.

Keyword: Hormones & Behavior; Emotions
Link ID: 8577 - Posted: 06.24.2010

By Katherine Unger The striking yodel of a male loon is no veiled threat. Loosely translated, the song means "you come here, and I'll pull all your feathers out," says biologist Charles Walcott of Cornell University in Ithaca, New York. Now, Walcott and colleagues have discovered that loons come up with fresh yodels when they move to new lakes, likely to make them stand out from the crowd. Earlier studies suggested that loons develop a distinctive yodel at a young age and stick with it. If that were true, Walcott and colleagues reasoned, they might be able to spot individual birds by their yodel. To test the idea, Walcott's team studied two populations of loons--one in Wisconsin and another in Michigan--that had already been banded, so the birds' identities could be confirmed. Male loons changed their calls only slightly from year to year, the researchers reported online 15 February in Animal Behaviour. But when the males relocated from one lake to another, as 10% to 15% do each year, Walcott's group heard something different. Comparing calls from 13 males recorded before and after a territory switch, researchers found that 12 males changed their songs significantly. "It came as a shock," says Walcott. "At first I didn't believe a word of it." © 2006 American Association for the Advancement of Science.

Keyword: Sexual Behavior; Animal Communication
Link ID: 8576 - Posted: 06.24.2010

A National Institutes of Health-sponsored clinical trial with 200 Parkinson's disease patients has shown that creatine and minocycline may warrant further consideration for study in a large trial, according to Karl Kieburtz, M.D., M.P.H., University of Rochester, who spoke today at the World Parkinson Congress on behalf of the trial investigators. Study investigators caution that while the news is encouraging, the results do not demonstrate that these agents are effective in Parkinson's disease. Before these interventions can be recommended as a treatment they must be tested in a larger trial with hundreds of patients. Study findings are available online and will be published in the March 14 issue of Neurology.* Parkinson's disease is a degenerative disorder of the brain in which patients may develop progressive tremor, slowness of movements, and stiffness of muscles. It affects approximately 1 percent of Americans over the age of 65. Although certain drugs, such as levodopa, can reduce the symptoms of Parkinson's, no treatment has been shown to slow the progressive deterioration in function. The National Institute of Neurological Disorders and Stroke (NINDS) of the National Institutes of Health (NIH) has organized a nationwide multi-center effort called NET-PD (Neuroprotection Exploratory Trials in Parkinson's Disease), a randomized, double-blind futility trial, to study compounds that may slow the clinical decline of Parkinson's disease. As the initial step in these efforts, creatine and the antibiotic minocycline were identified as agents worthy of preliminary study. Patients very early in the disease course who did not yet need medications typically used to treat their Parkinson's symptoms were included in the study.

Keyword: Parkinsons
Link ID: 8575 - Posted: 06.24.2010

MADISON - Recent research on the genetics of smoking has focused on genes that are thought to be related to nicotine metabolism, personality traits, and regulation of emotions. According to a genetic study just published in "Nicotine and Tobacco Research," genes responsible for taste also may yield important information about who smokes and why they smoke. Researchers from the University of Wisconsin-Madison and University of Utah wanted to determine if a "bitterness" gene-phenylthiocarbamide (PTC)-was related to smoking status and how important the taste of cigarettes is to a smoker. As predicted, those smokers who possessed less sensitivity to bitter taste were more likely to rate taste as a strong reason for smoking, and those who were sensitive to bitter taste were less likely to smoke for taste. A surprising result, which must be replicated for scientific accuracy, was the discovery that smokers with a different, less common genetic variant for taste were the least likely to smoke. "Nicotine dependence is likely to be the result of many genes and complex environmental effects," said Dale Cannon with the University of Utah, lead author of the study. "What this study tells us is that genetic factors involving the taste of cigarettes should be examined as part of the analysis of nicotine dependence."

Keyword: Drug Abuse; Chemical Senses (Smell & Taste)
Link ID: 8574 - Posted: 02.24.2006

Researchers at Yale School of Medicine have found evidence that a hormone produced in the stomach directly stimulates the higher brain functions of spatial learning and memory development, and further suggests that we may learn best on an empty stomach. Published in the February 19 online issue of Nature Neuroscience by investigators at Yale and other institutes, the study showed that the hormone ghrelin, produced in the stomach and previously associated with growth hormone release and appetite, has a direct, rapid and powerful influence on the hippocampus, a higher brain region critical for learning and memory. The team, led by Tamas L. Horvath, chair and associate professor of the Section of Comparative Medicine at Yale School of Medicine, and associate professor in the Department of Obstetrics, Gynecology & Reproductive Sciences, and Neurobiology, first observed that peripheral ghrelin can enter the hippocampus and bind to local neurons promoting alterations in connections between nerve cells in mice and rats. Further study of behavior in the animals showed that these changes in brain circuitry are linked to enhanced learning and memory performance. Because ghrelin is highest in the circulation during the day and when the stomach is empty, these results also indicate that learning may be most effective before meal-time.

Keyword: Learning & Memory; Obesity
Link ID: 8573 - Posted: 02.23.2006

Researchers led by Wolfgang Sadee, a scientist at the Ohio State University, have figured out how differences in one gene can make the brain more sensitive to alcohol, narcotics, or nicotine. The gene Sadee's team looked at has long been known to code for a kind of brain protein called an opioid receptor, which acts like a switch, turning on pleasure and blocking pain when triggered by certain addictive drugs. The surfaces of our brain cells are covered by different kinds of receptor proteins. These receptors act as chemical docking stations that allow individual brain cells to communicate with each other by sending and receiving small bursts of chemicals. Each type of receptor can only be activated by a certain class of chemicals, which makes the communication between brain cells specific and meaningful. However receptors can also respond to chemicals in the brain environment not sent by other cells, like things that we've ingested such as alcohol or particles from cigarette smoke. The mu-opioid receptor that Sadee's team looked at is the primary target for morphine, but it also plays a large part in responses to alcohol, nicotine, and narcotics such as cocaine. As reported in the Journal of Biological Chemistry, Sadee and his colleagues looked at two variations, A118G and G118 of the mu-opioid receptor gene. "We've taken a variation in this gene that's already suspected to affect the response to therapy of addiction, as well as addiction itself. But we didn't know how and why," he explains. © ScienCentral, 2000-2006.

Keyword: Drug Abuse; Genes & Behavior
Link ID: 8572 - Posted: 06.24.2010

There is little doubt that alcohol-related disorders in humans are genetically based. The influence of environmental factors, however, remains unclear. Given that studies of humans are complicated by a multitude of cultural and day-to-day-living factors, researchers in the March issue of Alcoholism: Clinical & Experimental Research use rhesus monkeys to examine genetic and environmental influences on alcohol consumption. Results indicate that, just as with humans, both genetic and environmental factors contribute to variation in alcohol consumption among the non-human primates. "Rhesus macaques provide a good model for many human diseases due in part to their phylogenetic closeness," said Joseph G. Lorenz, research associate at the Coriell Institute for Medical Research and corresponding author for the study. "Also, like humans, they are highly social, which is important for diseases like alcoholism where there are social factors affecting alcohol consumption. And, finally, because we can control their social environment and precisely measure their exposure to alcohol, whereas human studies often rely on self-reported consumption patterns."

Keyword: Drug Abuse; Genes & Behavior
Link ID: 8571 - Posted: 02.23.2006

Michael Hopkin Advances in the science of radiocarbon dating - a common, but oft-maligned palaeontological tool - have narrowed down the overlap between Europe's earliest modern humans and the Neanderthals that preceded them. Refinements to the technique, which estimates an artefact's age by sampling the amount of radioactive carbon left over from when it was formed, suggest that Homo sapiens wrested Europe from its prehistoric counterpart even quicker than had been thought. Previous estimates suggested that at least 7,000 years elapsed between H. sapiens arriving in eastern Europe more than 40,000 years ago, and the disappearance of the last known Neanderthals (H. neanderthalensis) from western France. But newly calculated dates shrink the overlap to 5,000 years. Radiocarbon dating, also known as carbon dating, is a reliable method for dating artefacts back to around 23,000 years ago. But for items older than this it has tended to underestimate ages by up to several thousand years. Carbon dating is based on the rate of decay of radioactive carbon-14 atoms found in living matter such as bones. Because carbon-14 decays to a non-radioactive form over time, older samples give off less radiation. ©2006 Nature Publishing Group

Keyword: Evolution
Link ID: 8570 - Posted: 06.24.2010