By NICHOLAS BAKALAR A young cigarette smoker can begin to feel powerful desires for nicotine within two days of first inhaling, a new study has found, and about half of children who become addicted report symptoms of dependence by the time they are smoking only seven cigarettes a month. “The importance of this study is that it contradicts what has been the accepted wisdom for many decades,” said Dr. Joseph R. DiFranza, the lead author, “which is that people had to smoke at least five cigarettes a day over a long period of time to risk becoming addicted to nicotine. Now, we know that children can be addicted very quickly.” Dr. DiFranza is a professor of family medicine at the University of Massachusetts. The researchers recruited 1,246 sixth-grade volunteers in public schools in Massachusetts, interviewing them 11 times over a four-year period. They also took saliva samples to determine blood levels of nicotine and link them to addictive behavior. At some time during the four years almost a third of the children puffed on a cigarette, more than 17 percent inhaled, and about 7.5 percent used tobacco daily. Since inhaling is required for sufficient drug delivery to cause dependence, the researchers limited their analysis, published in the July issue of The Archives of Pediatrics and Adolescent Medicine, to the 217 inhalers in the group. Their average age when they first inhaled was 12.8 years. Of these, almost 60 percent had lost some control over their smoking, and 38 percent developed tobacco dependence as defined by the widely used diagnostic manual published by the World Health Organization. Copyright 2007 The New York Times Company

Keyword: Drug Abuse; Development of the Brain
Link ID: 10553 - Posted: 06.24.2010

Scientists have discovered the first gene which appears to increase the odds of being left-handed. The Oxford University-led team believe carrying the gene may also slightly raise the risk of developing psychotic mental illness such as schizophrenia. The gene, LRRTM1, appears to play a key role in controlling which parts of the brain take control of specific functions, such as speech and emotion. The study appears in the journal Molecular Psychiatry. The brain is set up in an asymmetrical way. In right-handed people the left side of the brain usually controls speech and language, and the right side controls emotions. However, in left-handed people the opposite is often true, and the researchers believe the LRRTM1 gene is responsible for this flip. They also believe people with the LRRTM1 gene may have a raised risk of schizophrenia, a condition often linked to unusual balances of brain function. Lead researcher Dr Clyde Francks, from Oxford University's Wellcome Trust Centre for Human Genetics, said the next step would be to probe the impact on the development of the brain further. He said: "We hope this study's findings will help us understand the development of asymmetry in the brain. Asymmetry is a fundamental feature of the human brain that is disrupted in many psychiatric conditions." However, Dr Francks said left-handed people should not be worried by the links between handedness and schizophrenia. (C)BBC

Keyword: Laterality; Genes & Behavior
Link ID: 10552 - Posted: 07.31.2007

By JOHN TIERNEY Scholars in antiquity began counting the ways that humans have sex, but they weren’t so diligent in cataloging the reasons humans wanted to get into all those positions. Darwin and his successors offered a few explanations of mating strategies — to find better genes, to gain status and resources — but they neglected to produce a Kama Sutra of sexual motivations. Perhaps you didn’t lament this omission. Perhaps you thought that the motivations for sex were pretty obvious. Or maybe you never really wanted to know what was going on inside other people’s minds, in which case you should stop reading immediately. For now, thanks to psychologists at the University of Texas at Austin, we can at last count the whys. After asking nearly 2,000 people why they’d had sex, the researchers have assembled and categorized a total of 237 reasons — everything from “I wanted to feel closer to God” to “I was drunk.” They even found a few people who claimed to have been motivated by the desire to have a child. The researchers, Cindy M. Meston and David M. Buss, believe their list, published in the August issue of Archives of Sexual Behavior, is the most thorough taxonomy of sexual motivation ever compiled. This seems entirely plausible. Who knew, for instance, that a headache had any erotic significance except as an excuse for saying no? But some respondents of both sexes explained that they’d had sex “to get rid of a headache.” It’s No. 173 on the list. Copyright 2007 The New York Times Company

Keyword: Sexual Behavior
Link ID: 10551 - Posted: 06.24.2010

By BENEDICT CAREY In a recent experiment, psychologists at Yale altered people’s judgments of a stranger by handing them a cup of coffee. The study participants, college students, had no idea that their social instincts were being deliberately manipulated. On the way to the laboratory, they had bumped into a laboratory assistant, who was holding textbooks, a clipboard, papers and a cup of hot or iced coffee — and asked for a hand with the cup. That was all it took: The students who held a cup of iced coffee rated a hypothetical person they later read about as being much colder, less social and more selfish than did their fellow students, who had momentarily held a cup of hot java. Findings like this one, as improbable as they seem, have poured forth in psychological research over the last few years. New studies have found that people tidy up more thoroughly when there’s a faint tang of cleaning liquid in the air; they become more competitive if there’s a briefcase in sight, or more cooperative if they glimpse words like “dependable” and “support” — all without being aware of the change, or what prompted it. Psychologists say that “priming” people in this way is not some form of hypnotism, or even subliminal seduction; rather, it’s a demonstration of how everyday sights, smells and sounds can selectively activate goals or motives that people already have. Copyright 2007 The New York Times Company

Keyword: Miscellaneous
Link ID: 10550 - Posted: 06.24.2010

By CARL ZIMMER When Martin Nowak was in high school, his parents thought he would be a nice boy and become a doctor. But when he left for the University of Vienna, he abandoned medicine for something called biochemistry. As far as his parents could tell, it had something to do with yeast and fermenting. They became a little worried. When their son entered graduate school, they became even more worried. He announced that he was now studying games. In the end, Dr. Nowak turned out all right. He is now the director of the Program for Evolutionary Dynamics at Harvard. The games were actually versatile mathematical models that Dr. Nowak could use to make important discoveries in fields as varied as economics and cancer biology. “Martin has a passion for taking informal ideas that people like me find theoretically important and framing them as mathematical models,” said Steven Pinker, a Harvard linguist who is collaborating with Dr. Nowak to study the evolution of language. “He allows our intuitions about what leads to what to be put to a test.” On the surface, Dr. Nowak’s many projects may seem randomly scattered across the sciences. But there is an underlying theme to his work. He wants to understand one of the most puzzling yet fundamental features of life: cooperation. Copyright 2007 The New York Times Company

Keyword: Evolution
Link ID: 10549 - Posted: 06.24.2010

Kerri Smith A single gene can influence how clearly you recall emotionally intense memories, neuroscientists have shown. This finding could aid the search for therapies for people traumatized by horrific experiences. People with a particular gene variant are better at remembering emotionally laden memories than people with the more common version of the gene, research shows. The gene, called ADRA2B, is involved in detecting brain chemicals related to emotional arousal. This effect is specific to memories with emotional overtones, and does not affect emotion or memory by themselves. What matters is whether the event provokes an emotion — good or bad — and not how distressing the incident is. People's memories of scenes or events without emotional significance is not affected. The research highlighted the effect of the gene in stark terms: survivors of the 1994 Rwandan genocide were more likely to harbour persistent memories of the conflict if they had the variant version of the gene. The variant is present in 12% of people of African ancestry and in 30% of Causasians. Researchers led by Dominique de Quervain of the University of Zurich, Switzerland, made the discovery by presenting Swiss volunteers with emotionally neutral, positive or negative images — such as a family laughing together or a picture of an accident. They then asked them to write a description of the pictures ten minutes later. ©2007 Nature Publishing Group

Keyword: Emotions; Genes & Behavior
Link ID: 10548 - Posted: 06.24.2010

People who spend more time in the sun as children subsequently have a lower risk of developing multiple sclerosis (MS), a US study shows. The University of Southern California team suggest UV rays offer protection by altering the cell immune responses or by boosting vitamin D levels. An earlier study found women who took vitamin D supplements were 40% less likely to develop MS. The latest research is published in the journal Neurology. MS is among the most common neurological diseases affecting around two million people worldwide. However, it is more common at higher latitudes, which generally have lower levels of ultraviolet radiation - the type produced by the sun. People in these countries are exposed to less sunlight, which triggers a chemical reaction in the body leading to vitamin D production. For the study, researchers surveyed 79 pairs of identical twins who had the same genetic risk of MS. In each pair, one of the twins had MS. The twins were asked to specify whether they or their twin spent more time outdoors during hot days, cold days, and summer, and which one spent more time basking in the sun, going to the beach and playing team sports as a child. The researchers found the twin with MS spent less time in the sun as a child than the twin who did not have MS. (C)BBC

Keyword: Multiple Sclerosis
Link ID: 10547 - Posted: 07.30.2007

By NICHOLAS WADE Medical researchers have made a significant advance in understanding multiple sclerosis, a common neurological disease that causes symptoms ranging from muscle weakness to paralysis. The disease is one in which the body’s immune system mistakenly attacks the electrical insulation of nerve fibers. The cause is part genetic and part environmental, but researchers trying to identify the relevant genes have endured repeated frustration. Their approach has been to guess what genes might be involved and see if patients have abnormal versions. This guesswork has produced more than 100 candidate genes in recent years, none of which could be confirmed except for long-known variants in the mechanism used by the immune system to recognize proteins that are foreign to the body. In three articles published online yesterday in The New England Journal of Medicine, three teams of researchers say they have identified, by separate routes, new genetic variants that contribute to the disease. One team used a new, advanced gene-hunting method called Whole Genome Association, which has racked up a string of successes with major diseases in the last few months. The other teams used the candidate gene approach, but because all three teams identified the same gene, the researchers say they are confident they have opened a new window into the cause and possible treatment of multiple sclerosis. Copyright 2007 The New York Times Company

Keyword: Multiple Sclerosis
Link ID: 10546 - Posted: 06.24.2010

SEATTLE: – One of the greatest medical mysteries of our time has taken a leap forward in medical understanding with new study results announced by Dr. Daniel D. Rubens of Children’s Hospital and Regional Medical Center in Seattle. Rubens’ study published in July, 2007 in Early Human Development found all babies in a Rhode Island study group who died of Sudden Infant Death Syndrome (SIDS) universally shared the same distinctive difference in their newborn hearing test results for the right inner ear, when compared to infants who did not have SIDS. This is the first time doctors might be able to identify newborns at risk for SIDS by a simple, affordable and routine hearing test administered shortly after birth. In the study, medical records and hearing tests of 31 babies who died from SIDS in Rhode Island were examined and compared to healthy babies. Rhode Island has a particularly robust database of newborn hearing test data. The cause of SIDS, known around the world as “crib death” and “cot death,” has eluded physicians and grieving parents for centuries. Responsible for many previously unexplainable deaths of infants usually two to four months old and striking boys more than girls, SIDS causes tragic, sudden death in approximately 1 in 1,000 newborns world-wide, making it the largest cause of death in young infants. In the United States approximately 3,600 deaths each year were attributed to SIDS from 1992-1999, according to an April, 2004 article in Archives of Pediatric and Adolescent Medicine. Death occurs during sleep, seemingly with no warning and no previous symptoms. Changes in infant care have been promoted including the “Back to Sleep” program discouraging sleeping on the stomach, and avoiding exposure to cigarette smoke. Various causes have been suggested, including disturbances in respiratory control and infant overheating, but to date nothing has proven conclusive.

Keyword: Hearing; Sleep
Link ID: 10545 - Posted: 06.24.2010

Heidi Ledford People with one of two common gene variants may be at increased risk of developing the autoimmune disorder multiple sclerosis (MS), researchers say. Both variants encode components of the immune system that are involved in preventing the body from attacking its own cells. Two papers1,2 published today in Nature Genetics independently pinpoint one of the variants, in the 'interleukin-7 receptor alpha chain' (IL7R) gene. A third research team scanned the full genome for variants associated with MS, and found both IL7R and another interleukin receptor gene — 'interleukin-2 receptor alpha' (IL2R) — among the top hits3. In MS the body's immune system attacks the insulating sheath that surrounds and protects neurons, leading loss of motor function and cognitive decline. Interleukin-2 and interleukin-7 are immune system proteins that play a role in the function of regulatory T-cells, which help suppress autoimmunity. The three research teams analyzed thousands of patients of European descent, and found that a single base pair difference in the IL7R gene increased the risk of having MS by about 20%. That risk is too low to make IL7R useful for a genetic test, cautions Margaret Pericak-Vance, a geneticist at the University of Miami in Florida, and an author on one of the studies. "A lot of people carry this particular variant, and they don't get multiple sclerosis," she says. Roughly 70% of the European population is likely to have the variant. ©2007 Nature Publishing Group

Keyword: Multiple Sclerosis; Neuroimmunology
Link ID: 10544 - Posted: 06.24.2010

Paul Marks Your ability to recall emotional events – such as meeting the love of your life, or the trauma of a painful car crash – is governed by a common variation in a single gene, according to a new study. We recall emotionally charged events far more than mundane ones because they tend to be advantageous in evolutionary terms. Remembering favourable or dangerous events helps our survival far more than recalling the daily commute to work, for example. Highly emotive incidents trigger the brain to release the hormone and neurotransmitter noradrenaline. This stimulates the amygdala – part of the brain involved with processing emotional reactions – to store memories in the hippocampus and other parts of the brain, says Dominique de Quervain, a neuroscientist at the University of Zurich in Switzerland. Yet for some reason, recall of emotional events varies a great deal from person to person. So de Quervain wondered if common variations in a gene called ADRA2B, which codes for the noradrenaline receptor, could be responsible. Some 30 per cent of Caucasians and 12 per cent of Africans possess this variant, he says. To find out, he and colleagues in Germany and Uganda showed photos of strongly positive, neutral and strongly negative emotional events to two large groups of people. They later asked the group members to recall them and describe them in writing. © Copyright Reed Business Information Ltd.

Keyword: Emotions; Genes & Behavior
Link ID: 10543 - Posted: 06.24.2010

By Charles Q. Choi A male crayfish with larger-than-normal claws typically needs only to flash his menacing weapons to drive opponents away. Now researchers find these critters are frequently bluffing — the enlarged claws often aren't stronger at all. These findings raise the question of how often males in the animal kingdom are just bluffing with their natural weaponry. "Dishonesty during disputes may be far more prevalent that we previously imagined," said researcher Robbie Wilson, a zoologist at the University of Queensland in Australia. Wilson and an international team of researchers investigated the Australian slender crayfish (Cherax dispar). The small, lobster-like crustaceans are extraordinarily aggressive beasts, with combat often resulting in death or the loss of a limb. "When you pick them up, they'll want to take your finger off right away," Wilson said. These two- to three-inch long creatures were collected from the creeks on the sand islands off southeast Queensland. Crayfish are freshwater creatures, while lobsters are marine animals. The bluffing finding emerged when the scientists randomly pit 32 adult male crayfish against each other, two at a time, in plastic aquariums. © 2007 MSNBC.com © 2007 Microsoft

Keyword: Aggression
Link ID: 10542 - Posted: 06.24.2010

By Michael Balter Humans are highly social, but we don't get pally with just anybody. Before forming relationships with other people, we normally size them up to see how trustworthy they are. A new study suggests that this behavior stems from an evolutionary reorganization in a part of the brain responsible for detecting other people's emotions. The amygdala, a small, almond-shaped area deep within our brains, appears to be essential in helping us read the emotions of others. Research shows that the structure is crucial for detecting fear, but scientists have also found evidence that it can help spot a wide variety of mental states (ScienceNOW, 7 April 2006). Last year, for example, scientists noted that the amygdalas of patients with autism, which is characterized by decreased social interaction and an inability to understanding the feelings of others, have fewer nerve cells, especially in a subdivision called the lateral nucleus. To see how the amygdala varies in different primate species, a team led by anthropologist Katerina Semendeferi of the University of California, San Diego, measured brain area in autopsy material from 12 ape and human specimens. The researchers found that although the human amygdala was much larger than those of the apes, it was actually the smallest when compared to overall brain size. © 2007 American Association for the Advancement of Science.

Keyword: Emotions
Link ID: 10541 - Posted: 06.24.2010

Cochlear implants bring hearing to thousands of otherwise deaf people. However, they have their limitations. John Middlebrooks of the University of Michigan's Kresge Hearing Research Institute explains how a new implant could improve pitch perception. Below is a transcript of the interview: This is an image of the cochlea of the human inner ear. The cochlea is a sort of a spiral snail shell. It has two and a half turns in the human. So here’s one, two, and a half turns. Now we see here a conventional cochlear implant. And notice that the cochlear implant only goes about one of the turns of the cochlea, so it doesn’t reach the apical turns of the cochlea that are sensitive to the lowest frequencies. Also notice that the cochlear implant resides within a bony chamber here called the scala tympani, so the signal from the cochlear implant has to go across this wall of bone to reach the auditory nerve fibers. The nerve implant that we’re testing now actually is inserted into the auditory nerve fibers so that the electrodes of the nerve implant lie in intimate contact with those auditory nerve fibers. Who are cochlear implants for? How do they work? Cochlear implants are used for people who are profoundly or severely deaf, so these are people that have often essentially no hearing through a conventional hearing aid. And these people have lost the hair cells that transduce sound into neural activity. So we can replace the function of those hair cells with a microphone and … electrodes. © ScienCentral, 2000-2007.

Keyword: Hearing; Robotics
Link ID: 10540 - Posted: 06.24.2010

Bruce Bower Although a variety of personal traits influence weight gain, obesity is socially contagious, moving from person to person through networks of friends and relatives, a new investigation finds. The study, the first to examine how social ties influence the development of obesity over time, finds that if one person becomes obese, others who know that person well have an increased risk of also becoming obese within the next 4 years. This effect occurs especially strongly among people identifying each other as friends. The proliferation of permissive attitudes about weight gain and large body sizes among social groups has contributed to soaring U.S. obesity rates, propose medical sociologist Nicholas A. Christakis of Harvard Medical School in Boston and political scientist James H. Fowler of the University of California, San Diego. "Obesity is not just an individual problem, it's a collective problem," Christakis says. The new findings appear in the July 26 New England Journal of Medicine. Christakis and Fowler tapped into previously unexamined data on 12,067 adults who underwent health assessments every 2 to 4 years, from 1971 to 2003, as part of the Framingham Heart Study. The researchers traced social networks for study participants by consulting records of contact information for each volunteer's close friends and relatives, many of whom also participated in the Framingham study and whose weights could also be tracked. ©2007 Science Service.

Keyword: Obesity
Link ID: 10539 - Posted: 06.24.2010

By Tuan C. Nguyen Until recently, wildlife biologists considered foxes, wolves and coyotes to be monogamous, a strategy that was presumed to give offspring a better chance of surviving, since monogamy often means that females have the helping hand of a male in raising newborns to adulthood. But a new study of Arctic foxes, detailed in the Canadian Journal of Zoology, finds that some do sleep around. Using a technique called microsatellite DNA fingerprinting, researchers at the University of Alberta in Edmonton and the University of Quebec at Rimouski looked at genetic samples from 49 Arctic foxes trapped in dens on Bylot Island, Nunavut. In three-quarters of the dens, fox cubs were the offspring of a single male and female. But in a quarter of the cases, the Arctic foxes proved to be less exclusive, with one litter providing the first genetic evidence of polyandry. "The generalization that mating couples stuck together usually came from field observations," said researcher Lindsey Carmichael of the University of Alberta in Edmonton. "People would often see pairs of foxes together and so they would just assume that was their standard mating pattern." There are various reasons for polyandry. © 2007 MSNBC.com © 2007 Microsoft

Keyword: Sexual Behavior
Link ID: 10538 - Posted: 06.24.2010

Louis Buckley Gender-bending chemicals could provide a new way to combat invasive species, say researchers. Originally conceived as a cure for the enormous populations of Asian carp and tilapia plaguing the Mississippi River, scientists now think the approach could be used to battle unwelcome crustaceans, molluscs, fish, amphibians and reptiles around the world. Invasions of exotic species are thought to be second only to habitat destruction as a threat to global biodiversity. The traditional approach to dealing with these interlopers has been to introduce a known predator and let nature take its course. But this has led to numerous disasters — for example, cane toads swamped Australia after being introduced to control the cane beetles blighting the country's sugar crop. In Florida, tilapia were deliberately introduced to control an aquatic weed, Hydrilla, that has been choking US rivers since the 1960s. Two species of snail were also introduced at a later date by the authorities, says Gutierrez, but neither they nor the tilapia chose to feed on Hydrilla, both preferring native species to the invader. In 2004, alerted to Florida's problems with invasive species, Juan Gutierrez, a bio-mathematician at Florida State University, constructed a mathematical model of a population in which males carry two different sex chromosomes (XY) and females are XX. In many species of fish, amphibians, and other animals, gender is determined not only by sex chromosomes, as it is in humans, but also by environmental conditions such as the presence of hormones, explains Gutierrez. ©2007 Nature Publishing Group

Keyword: Sexual Behavior; Evolution
Link ID: 10537 - Posted: 06.24.2010

Cochlear implants have been around for years, restoring hearing for many people. But, as this ScienCentral video explains, a new version is improving the quality of what patients hear. Dr. David Acus of Herrick Memorial Hospital in Tecumseh, Michigan was a twenty-five year veteran of the emergency room when hearing loss forced him to quit his job. Then he got a cochlear implant. “The cochlear implant is wonderful. It’s allowed me to go back to work.” In a healthy ear, vibrations are translated into electrical signals inside the cochlea, a small bony structure of the inner ear. The signals are sent to the brain via the auditory nerve. Congenital problems, injury, illness, or aging can cause hearing loss. One solution is to insert an electrical array into the cochlea that translates external sounds into electrical impulses. These conventional cochlear implants are remarkably effective, and have improved the hearing of nearly 100,000 deaf people worldwide. However, the implants stimulate the ear's auditory nerve indirectly, through the bony wall of the cochlea. Neuroscientist John Middlebrooks of the University of Michigan points out that muddles music and vocal tones. “It’s a little bit like playing a piano with boxing gloves on your hands: you can make a big sound, and you can touch all the keys, but you can’t play single keys individually.” © ScienCentral, 2000-2007.

Keyword: Hearing; Robotics
Link ID: 10536 - Posted: 06.24.2010

Daniel Cressey Frequent cannabis use more than doubles the risk of developing psychotic illnesses such as schizophrenia, according to the most rigorous analysis of the evidence to date. The finding, which comes from a new study that combines results from 35 previous surveys, represents a significant U-turn from previous suggestions that cannabis is harmless to mental health. The analysis is published in medical journal The Lancet, which in 1995 began one of its issues with the sentence: "The smoking of cannabis, even long term, is not harmful to health."1 In fact, having used the drug even once increases your risk of developing psychotic problems by 41%, according to the new research2. This suggests that 14% of all psychotic illness in Britain is caused by cannabis use. "The message that has to be made clear is there are potentially quite serious risks from using cannabis," says study author Stanley Zammit of Cardiff University, UK. "For psychotic outcomes there certainly is enough evidence to warn people of the risk." Zammit adds that the new analysis is the "most thorough" to date. "This adds a certain robustness to the evidence," he says. There is now sufficient evidence to warn young people that using cannabis could increase their risk of developing a psychotic illness later in life' ©2007 Nature Publishing Group

Keyword: Drug Abuse; Schizophrenia
Link ID: 10535 - Posted: 06.24.2010

Scientists believe they have identified the gene for itchiness, raising the hope of treatment for the condition. The GRPR "itch gene" was found in spinal cord nerve cells by a Washington University team. The researchers, who carried out tests on mice, say it is responsible for relaying itch signals from the skin to the brain, via the spinal cord. They say if they are right, it may hold the key for helping people with severe itching, the Nature journal reported. Chronic itching can be caused by skin disorders like eczema or can stem from deeper problems such as kidney failure or liver disease. It can also be a serious side-effect of cancer therapies or powerful painkillers like morphine. In the most serious cases it can lead to sleep problems and scarring, and yet researchers say there is little treatment available for it. Historically, scientists have regarded itching as a less intense version of pain and have tailored their research to understanding pain. In fact, it was during such research that the GRPR (gastrin-releasing peptide receptor) gene first came to the scientists' attention. The gene stood out as they noticed it was only present in a few spinal cord cells, but after carrying out tests on mice they realised it was not related to the pain pathway. However, they did find it had an impact when itching tests were carried out. Mice who had the gene neutralised did not react as much as those with the gene when given itchy stimuli. (C)BBC

Keyword: Pain & Touch
Link ID: 10534 - Posted: 07.27.2007