Some cases of cot death may be due to a bacterial infection, researchers say. The Archives of Disease in Childhood study found samples from babies who had died for no apparent reason often carried potentially-harmful bacteria. Some experts believe toxins produced by these bacteria could trigger a chemical storm, which overwhelms the baby, resulting in sudden death. There are around 250 sudden infant deaths a year in the UK. The majority are never fully explained. Scientists know that there are certain things that parents can do to cut the risk of cot death - such as not smoking during or after pregnancy, and putting babies to sleep on their backs, but the precise reasons why this helps are not completely understood. Associate professor Paul Goldwater, from The Women's and Children's Hospital and the University of Adelaide in Australia, who carried out the latest research, believes bacterial infections may contribute to some sudden infant deaths. He analysed the post mortem reports for 130 babies who had died of sudden infant death syndrome (SIDS), 32 who had died suddenly as a result of infection, and 33 who had died of non-infectious cause, such as a road traffic accident. He then analysed the bacterial isolates from "sterile" sites which are normally free of infections, such as heart blood, spleen, or cerebrospinal fluid, in the SIDS babies, and compared these with those of the other 65 babies. Infection at a sterile site was rare in those infants who had died of non-infectious causes, but this was relatively common in both the SIDS babies and the babies who had died suddenly as a result of infection. Unsurprisingly, almost one in five of the babies who had died suddenly as a result of infection had a sterile site infection. But so too did one in 10 of the SIDS babies. (C)BBC

Keyword: Sleep; Development of the Brain
Link ID: 12032 - Posted: 09.11.2008

Bob Holmes HOW do you go about finding a mate? For female barking tree frogs it appears the trick is to use complex calculations to pick out the loudest male in a chorus, even when distance makes him sound quieter than a nearer rival. To determine the females' favourite mating call, Christopher Murphy, a behavioural ecologist at James Madison University in Harrisonburg, Virginia, played captured frogs an artificial chorus of male calls from an array of loudspeakers. The females hopped towards the call they found most attractive. Females generally preferred louder calls, probably because they indicate a bigger, stronger male. Indeed, when Murphy played the louder call through a more distant speaker, so that a closer but lower-volume call sounded louder to the female, she still chose the speaker with the inherently louder call (Journal of Comparative Psychology, vol 122, p 264). This suggests that females have some way of judging a male's distance apart from how loud his call appears. "They're smarter than I realised," says Murphy. He adjusted the sound again to rule out two techniques the frogs might use: judging distance by how the sound degrades, or working out how quickly the sound gets louder as they approach. © Copyright Reed Business Information Ltd

Keyword: Hearing; Sexual Behavior
Link ID: 12031 - Posted: 06.24.2010

By Rachel Zelkowitz Standing alone in a dark alley, you whirl around at the sound of footsteps. A figure moves in the distance, its silhouette barely visible by a sliver of moonlight. Is the stranger coming toward you? If he's a man, your senses will tell you yes, according to a new study, even if he's actually walking away. How someone walks can reveal their feelings. Slumped shoulders and a labored gait, for example, indicate unhappiness. Researchers often study these kinds of signals using something called a point-light figure, a collection of dots arranged in a human form. The figure is supposed to convey minimal information, but simple manipulations--broadening the dots on the shoulder region or narrowing dots that represent the waist--can make figures seem more masculine or more feminine. Ben Schouten, a psychologist at the University of Leuven in Belgium, and colleagues tested whether giving the point-light figure a distinctive gender would affect how an observer perceives its motion. They asked five volunteers--three women and two men--to watch videos of point-light figures on a computer screen. By changing the point arrangements, the researchers made the figures seem either very masculine, very feminine, or gender-neutral. The subjects watched a 3- to 4-second clip of the figure walking and had to identify whether the figure was moving toward or away from them. The researchers then showed a second set of videos that incorporated subtle shifts of movement in the background to give more information on the walker's direction. © 2008 American Association for the Advancement of Science.

Keyword: Sexual Behavior; Emotions
Link ID: 12030 - Posted: 06.24.2010

By Pascal Belin The use of vocalizations, such as grunts, songs or barks, is extremely common throughout the animal kingdom. Nevertheless, humans are the only species in which these vocalizations have attained the sophistication and communicative effectiveness of speech. How did our ancestors become the only speaking animals, some tens of thousands of years ago? Did this change happen abruptly, involving the sudden appearance of a new cerebral region or pattern of cerebral connections? Or did it happen through a more gradual evolutionary process, in which brain structures already present to some extent in other animals were put to a different and more complex use in the human brain? A recent study in Nature Neuroscience yields critical new information, uncovering what could constitute the “missing link” between the brain of vocalizing nonhuman species and the human brain: evidence that a cerebral region specialized for processing voice, known to exist in the human brain, has a counterpart in the brain of rhesus macaques. Neuroscientist Christopher I. Petkov of the Max Planck Institute for Biological Cybernetics in Tübingen, Germany, and his colleagues used functional magnetic resonance imaging to explore the macaque brain. They measured cerebral activity of awake monkeys that were listening to different categories of natural sounds, including macaque vocalizations. The researchers found evidence for a “voice area” in the auditory cortex of these macaques: a discrete region of the anterior temporal lobe in which activity was greater for macaque vocalizations than for other sound categories. © 1996-2008 Scientific American Inc.

Keyword: Language; Evolution
Link ID: 12029 - Posted: 06.24.2010

Vigorous physical activity could blunt the effects of a common gene linked to obesity, claim US researchers. Carrying two copies of the FTO gene significantly increases the chances of becoming obese. However, a study carried out among the US Amish community found an active lifestyle appeared to remove this risk. A UK specialist said the results, reported in the Archives of Internal Medicine journal, would be interesting if repeated by larger studies. The complex relationships between our genes and lifestyles, which can mean obesity for some people and not for others, has yet to be fully understood. Several genetic variants have been linked to obesity, but none is wholly responsible for it. The most common of these is FTO, with half of all people in Europe carrying either one or two copies of it. It is not clear how it influences weight gain, although some scientists have suggested it may play a role in an individual's appetite. The study from the University of Maryland supports other research which suggests that a person's level of exercise may help determine whether their genetic makeup will contribute to obesity. The researchers looked at 704 Amish men and women, chosen because of that community's relative genetic "purity", with members generally able to trace their ancestry back for 14 generations to early settlers from Europe. Volunteers were fitted with "accelerometers", measuring their precise movements over a period of time. They found that while the expected link between the number of copies of FTO carried and increased body mass index could be seen in less active volunteers, that link was broken once in those who recorded high levels of activity - equivalent to three to four hours of moderately intensive activity. (C)BBC

Keyword: Obesity; Genes & Behavior
Link ID: 12028 - Posted: 09.09.2008

For years, researchers have known that women are twice as likely to develop depression as men and they suffer a wider range of symptoms. But when it came to prescribing effective treatments, researchers couldn't agree if gender mattered. As some small studies suggested, certain drugs worked better in women than men. Could there be significant biological differences in how each gender responded to these medications? A $35 million, federally funded study, was commissioned to answer the controversy, and its just-published results suggest that the answer to both questions is a probable yes. The STAR*D (Sequenced Treatment Alternatives to Relieve Depression) study, the largest and most rigorous depression study done to date, enrolled 2,876 men and women (ages 18 to 75) from 41 treatment centers with funding from the National Institute of Mental Health (NIMH). All participants were treated for 12 to 14 weeks with citalopram (popularly known as Celexa), a selective serotonin reuptake inhibitor (SSRI), currently the most popular class of antidepressants on the market. Even though the women in the study generally had more severe depressive symptoms than the men, they were 33 percent more likely than the male participants to achieve a full remission. "These results are very exciting because they give more confirmation that gender is a factor that should be considered when prescribing treatment for depression," said Dr. Susan Kornstein, professor of psychiatry and obstetrics/gynecology at Virginia Commonwealth University, and one of the study's lead authors. "This is one more big piece of the puzzle as we try to understand sex differences in treatment response." The results were recently published in the online version of the Journal of Psychiatric Research. © 2008 Newsweek, Inc.

Keyword: Depression; Sexual Behavior
Link ID: 12027 - Posted: 06.24.2010

A vitamin found in meat, fish and milk may help stave off memory loss in old age, a study has suggested. Older people with lower than average vitamin B12 levels were more than six times more likely to experience brain shrinkage, researchers concluded. The University of Oxford study, published in the journal Neurology, tested the 107 apparently healthy volunteers over a five-year period. Some studies suggest two out of five people are deficient in the vitamin. The problem is even more common among the elderly, and recent moves to supplement bread with folic acid caused concern that this could mask B12 deficiency symptoms in older people. The Oxford study looked at a group of people between 61 and 87, splitting it into thirds depending on the participants' vitamin B12 levels. Even the third with the lowest levels were still above a threshold used by some scientists to define vitamin B12 deficiency. However, they were still much more likely to show signs of brain shrinkage over the five-year period. Professor David Smith, who directs the Oxford Project to Investigate Memory and Ageing, said he now planned a trial of B vitamins in the elderly to see if taking them could slow brain shrinkage. He said: "This study adds another dimension to our understanding of the effects of B vitamins on the brain - the rate of shrinkage of the brain as we age may be partly influenced by what we eat." Shrinkage has been strongly linked with a higher risk of developing dementia at a later stage and Rebecca Wood, the chief executive of the Alzheimer's Research Trust, said further research was needed. "This study suggests that consuming more vitamin B12 through eating meat, fish, fortified cereals or milk as part of a balanced diet might help protect the brain. Liver and shellfish are particularly rich sources of B12. "Vitamin B12 deficiency is a common problem among elderly people in the UK and has been linked to declining memory and dementia." (C)BBC

Keyword: Alzheimers; Learning & Memory
Link ID: 12026 - Posted: 09.09.2008

By NICHOLAS BAKALAR Failure to properly absorb vitamin B12, found in meat, milk and eggs, has been implicated in various neurological disorders. Now a British study suggests that low levels of the vitamin in older people may cause the brain to shrink. The study, published Tuesday in Neurology, included 107 men and women, average age 73, who had no mental impairments. Researchers used M.R.I. scans to measure brain volume and blood tests to record vitamin B12 levels. They divided the subjects into three groups, based on their level of the vitamin, and followed them for five years with annual scans and physical and mental examinations. The group with the lowest levels of vitamin B12 lost twice as much brain volume as those with the highest levels. The difference was significant even after controlling for initial brain size, age, sex, education, cognitive test scores and various measures of blood chemistry. David Smith, an emeritus professor of pharmacology at Oxford and the lead author of the study, said the work established an association, but not a causal connection. “This doesn’t mean you should go out and buy vitamin B12 tablets tomorrow,” he said. “We need to know the results of a clinical trial in which we’re testing whether B12 does actually prevent brain shrinkage.” Copyright 2008 The New York Times Company

Keyword: Alzheimers
Link ID: 12025 - Posted: 06.24.2010

By KEVIN SACK and BRENT McDONALD DALLAS — With a friend videotaping, 27-year-old Christopher Lenzini of Dallas took a hit of Salvia divinorum, regarded as the world’s most potent hallucinogenic herb, and soon began to imagine, he said, that he was in a boat with little green men. Mr. Lenzini quickly collapsed to the floor and dissolved into convulsive laughter. Nathan K. calls his use of salvia “just a very gentle letting go, a very gentle relaxing.” When he posted the video on YouTube this summer, friends could not get enough. “It’s just funny to see a friend act like a total idiot,” he said, “so everybody loved it.” Until a decade ago, the use of salvia was largely limited to those seeking revelation under the tutelage of Mazatec shamans in its native Oaxaca, Mexico. Today, this mind-altering member of the mint family is broadly available for lawful sale online and in head shops across the United States. Though older Americans typically have never heard of salvia, the psychoactive sage has become something of a phenomenon among this country’s thrill-seeking youth. More than 5,000 YouTube videos — equal parts “Jackass” and “Up in Smoke” — document their journeys into rubber-legged incoherence. Copyright 2008 The New York Times Company

Keyword: Drug Abuse
Link ID: 12024 - Posted: 06.24.2010

Duncan Graham-Rowe It was six months after her operation that Elisabeth Bryant first started to see the effects, quite literally. Clinically blind, Bryant began to make out the swinging pendulum of her grandfather clock from across the room. Since then her vision improved to the point that she could read large print editions of Reader's Digest, send emails and continue with past activities like sewing and knitting. Bryant is one of ten patients to have received a retinal transplant as part of a phase II trial to replace diseased photoreceptors in conditions such as retinitis pigmentosa (RP) and age-related macular degeneration (AMD). Before the transplant she could see nothing but shadows. But within a year her vision had improved from 20/800 to 20/160, a remarkable recovery. Each of the patients in the trial received a small 4 millimetre square of retinal tissue, complete with retinal progenitor cells and the retinal pigment epithelium that nourishes them. The tissues were placed in the sub-retinal space beneath the fovea, the area of the retina responsible for sharp central vision. Seven of the subjects experienced an improvement in their visual acuity, says Norman Radtke, the ophthalmologist who carried out the surgery at the Retina Vitreous Resource Center in Louisville, Kentucky. The results are reported in the August issue of the American Journal of Ophthalmology1. © 2008 Nature Publishing Group

Keyword: Vision
Link ID: 12023 - Posted: 06.24.2010

By NICHOLAS BAKALAR The older a man is, the more likely he is to father children who develop bipolar disorder as adults, a large Swedish study reports. Previous studies have found an association between paternal age and both autism and schizophrenia, but this is the first time a connection with bipolar illness has been suggested. The study appears in the September issue of The Archives of General Psychiatry. The researchers examined highly accurate Swedish government health records of more than seven million people with known biological parents to find 13,428 with bipolar disorder diagnosed at two or more separate hospital admissions. They matched each case with five controls, people of the same age and sex but without bipolar illness. They divided the fathers into five-year age categories beginning at 20. After statistically adjusting for the age of the mother, family history of psychotic disorders, education level and other factors, they found consistently increasing risk as fathers aged. The highest risk was in fathers 55 and older. For mothers, after adjusting for the father’s age, they found a statistically significant increase in only the 35 to 39 age group. Copyright 2008 The New York Times Company

Keyword: Schizophrenia
Link ID: 12022 - Posted: 06.24.2010

Telling someone you fancy 'I really like you' could make him or her find you more attractive, research suggests. Making eye contact and smiling have a similar effect, says Aberdeen University psychologist Dr Ben Jones. His study, involving 230 men and women, found such social cues - which signal how much others fancy you - play a crucial role in attraction. The work will appear in Psychological Science and will be presented at the BA Festival of Science in Liverpool. Dr Jones said singletons could use his findings to help prevent wasting time chatting up people who were clearly not interested. "Combining information about others' physical beauty with information about how attracted they appear to be to you allows you to allocate your social effort efficiently," he said. In other words, avoid wasting time on attractive individuals who appear unlikely to reciprocate. In the study, 230 men and women were asked to look at flash cards picturing a face with different expressions - making eye contact or not and smiling or not. The volunteers were then asked to rate how attractive the faces were. The preference for the attractive face was much stronger when people were judging those faces that were looking at them and smiling. (C)BBC

Keyword: Sexual Behavior
Link ID: 12021 - Posted: 09.08.2008

By Bruce Bower Count on evolution to play favorites. When it comes to math achievement, some kids may start out with an inherent advantage. A portion of 14-year-olds deftly estimate approximate quantities of items without counting, whereas others do so with either moderate or limited success, a new study finds. The ability is evolutionarily ancient and cannot be taught, but tends to get better with age. Large variations in this number sense closely parallel youngsters’ mathematics achievement scores from kindergarten to sixth grade, concludes a team reporting in the Sept. 7 Nature and led by psychologist Justin Halberda of Johns Hopkins University in Baltimore. Earlier studies indicated that a faculty for rapidly estimating approximate quantities appears by age 4 months, long before any math instruction. How precisely a child can estimate amounts may influence math learning and achievement, Halberda proposes. He and his colleagues are now assessing this ability in 3-year-olds whose math achievement in elementary school will be tracked. It’s also possible that high-quality or intensive math instruction may increase the accuracy of a person’s number estimates. Halberda suspects that if such effects exist, they’re relatively small. © Society for Science & the Public 2000 - 2008

Keyword: Intelligence; Development of the Brain
Link ID: 12020 - Posted: 06.24.2010

By Christian Hoppe and Jelena Stojanovic Within hours of his demise in 1955, Albert Einstein’s brain was salvaged, sliced into 240 pieces and stored in jars for safekeeping. Since then, researchers have weighed, measured and otherwise inspected these biological specimens of genius in hopes of uncovering clues to Einstein’s spectacular intellect. Their cerebral explorations are part of a century-long effort to uncover the neural basis of high intelligence or, in children, giftedness. Traditionally, 2 to 5 percent of kids qualify as gifted, with the top 2 percent scoring above 130 on an intelligence quotient (IQ) test. (The statistical average is 100. See the box on the opposite page.) A high IQ increases the probability of success in various academic areas. Children who are good at reading, writing or math also tend to be facile at the other two areas and to grow into adults who are skilled at diverse intellectual tasks [see “Solving the IQ Puzzle,” by James R. Flynn; Scientific American Mind, October/November 2007]. Most studies show that smarter brains are typically bigger—at least in certain locations. Part of Einstein’s parietal lobe (at the top of the head, behind the ears) was 15 percent wider than the same region was in 35 men of normal cognitive ability, according to a 1999 study by researchers at McMaster University in Ontario. This area is thought to be critical for visual and mathematical thinking. It is also within the constellation of brain regions fingered as important for superior cognition. These neural territories include parts of the parietal and frontal lobes as well as a structure called the anterior cingulate. © 1996-2008 Scientific American Inc.

Keyword: Intelligence
Link ID: 12019 - Posted: 06.24.2010

When my own daughter was born by cesarean section delivery, I was surprised how uninvolved I was in the process. My body was numb, and my view of the surgery was blocked by a sheet. When I finally heard a baby cry, it took a minute for me to realize that the sound belonged to my own baby. That’s why I was particularly interested to read of new research showing that the method of delivery seems to influence how a mother’s brain responds to the cries of her own baby. The brains of women who have natural childbirth appear to be more responsive to the cries of their own babies, compared to the brains of women who have C-section births. The finding is based on brain imaging scans conducted two to four weeks after delivery among just 12 women, half of whom had vaginal births and half of whom gave birth by C-section. The study, published in The Journal of Child Psychology and Psychiatry, found that the cry of a woman’s own baby triggered significant responses in several parts of the brain related to sensory processing, empathy, arousal, motivation, reward and habit-regulation. The effect was greatest in the brains of women who had delivered vaginally compared to those women who delivered their babies by C-section. The conclusions that can be drawn from the study are limited because it involved so few women. However, it does support the theory that C-section birth may result in slight delays in attachment, putting those women at slightly higher risk for postpartum depression. Copyright 2008 The New York Times Company

Keyword: Sexual Behavior; Depression
Link ID: 12018 - Posted: 06.24.2010

By Tabitha M. Powledge Researchers have discovered that the same nerve cells involved in forming memories also are involved in replaying them. The finding, published today in the online edition of Science, provides new insight into how complex memories are laid down in a single neuron (nerve cell) and how neural firing, or communication, patterns created during memory formation are maintained during recall. Scientists at the University of California, Los Angeles, (U.C.L.A.) showed 13 volunteers—epilepsy patients with therapeutic electrodes implanted in their brains—several five- to 10-second clips from videos such as The Simpsons. The researchers found that a small sample comprising some 50 neurons in the hippocampus and entorhinal cortex (memory centers in the brain) fired in distinctive repeatable patterns that differed for each clip. "The results were quite astounding," says senior study author Itzhak Fried, director of the U.C.L.A. Health System's Epilepsy Surgery Program. The same neuron that activated during the original viewing of a specific snippet also fired during recall, and the action began a second or so before the patient reported seeing the clip. That means, Fried says, that "the very neuron that was selectively active during the encoding, during the original viewing, suddenly came to life. It essentially replayed that memory by firing." © 1996-2008 Scientific American Inc.

Keyword: Learning & Memory
Link ID: 12017 - Posted: 06.24.2010

Jennifer Viegas -- Harmonious bird songs may sound pleasant to people, but a new study has found that at least some birds fight by singing, using melodic tweets to defend their relationships and territories. The study, published in the latest issue of Current Biology, was made possible by eight microphones positioned strategically throughout the dense tropical forests of Costa Rica. The microphones fed the song duets of rufous-and-white wrens into a single laptop computer, enabling researchers to pinpoint the exact positions of the colorful songbirds. "The first time I heard a rufous-and-white wren song, I was completely captivated by its voice," lead author Daniel Mennill told Discovery News. "They have low-pitched, flute-like sounds that are really quite beautiful." Mennill, an associate professor in the Department of Biological Sciences at the University of Windsor, and colleague Sandra Vehrencamp conducted two experiments on breeding pairs of the birds, which can sing such closely matched duets that human listeners think they're hearing a solo performance. They first recorded the birds in a passive context. "This is analogous to recording you as you go about your daily routine of making your lunch, tidying your house, etc.," explained Mennill. © 2008 Discovery Communications, LLC

Keyword: Sexual Behavior; Language
Link ID: 12016 - Posted: 06.24.2010

Amber Dance Infectious prion proteins from hamsters can change normal proteins from mice into new, infectious forms of prion - simply by mixing the proteins together in a test tube. Researchers at the University of Texas Medical Branch in Galveston suggest their discovery could be turned into a useful test for whether a given prion strain is transmissible from one species to another. Prion proteins are responsible for Creutzfeld-Jakob disease and "mad cow" disease. But they also found that when a prion jumps species, it produces a new kind of prion. "This is very worrisome," says Claudio Soto, who led the research, published in Cell1. "The universe of possible prions could be much larger than we thought." Normal prion protein, or PrP, is found throughout the body but is concentrated in the brain. Its exact role is not known, although it has been linked to cell signalling2, metal-ion transport3, and blood-cell manufacture4. The protein can adopt malformed shapes that cause disease. Those proteins, which are resistant to degradation, bind and convert normal protein to their troublesome conformation. Over time, the diseased protein builds up and forms fibrils in the brain, causing neurodegeneration and ultimately death. © 2008 Nature Publishing Group

Keyword: Prions
Link ID: 12015 - Posted: 06.24.2010

As little as 20 minutes a day of aerobic exercise could help people over 50 improve their memory, a new study suggests. Results of the randomized control trial study appear in Wednesday's issue of the Journal of the American Medical Association. Dr. Nicola Lautenschlager of the University of Melbourne and her colleagues tested whether exercise would reduce the rate of cognitive decline among 138 people over 50 at increased risk for dementia. Half were randomly assigned to an education group, and the rest participated in a 24-week physical activity program. "What our trial tells us is that older people who take up some form of aerobic exercise for as little as 20 minutes a day will be more likely to remember things like shopping lists, family birthdays and friends' names," said study author Prof. Leon Flicker of the Western Australian Institute for Health and Aging. "What's interesting about this study is that physical activity doesn't just have benefits for memory and preventing Alzheimer's disease, it highlights the importance of exercise to boost overall well-being and mental health." Medications approved to aid mental function in Alzheimer's disease had "no significant effect on mild cognitive impairment at 36 months," the researchers said, while physical activity not only helped cognitive function, but also depression, quality of life and cardiovascular function. © CBC 2008

Keyword: Learning & Memory; Alzheimers
Link ID: 12014 - Posted: 06.24.2010

By SARAH KERSHAW AS sisters only four months apart, Julie and Sara Curry grew up being peppered with questions from confused classmates. Your mom was in labor for four months? asked one friend, said Sara, 19. How is it possible? others inquired. The Curry sisters, college sophomores who live with their parents in this high desert town on the outskirts of San Diego, are what Dr. Nancy L. Segal, a psychologist who is researching behavioral differences among twins, refers to as virtual twins. By her definition, virtual twins are unrelated children born within nine months of each other who enter a family, through birth or adoption, in the first year of life. Since 1991, Dr. Segal has been studying 137 such sets of siblings, whose average age difference is three months. As scientific subjects, virtual twins provide a rich pool of material for researchers tackling the nature-versus-nurture question. In Dr. Segal’s studies, as in so many involving biological twins, it seems that nature is winning. Raised together essentially from birth, or at least since infancy, virtual twins may be genetic strangers, but they share an environment from an early point in life. A twin herself, Dr. Segal runs the Twin Studies Center at California State University, Fullerton, and is the author of two books on twins. She said her work has shown that virtual twins have less in common in terms of behavior, intelligence and decision-making than fraternal or identical twins, including those reared apart, or even biological siblings several years apart in age. Copyright 2008 The New York Times Company

Keyword: Genes & Behavior
Link ID: 12013 - Posted: 06.24.2010