Tiny worm-like creatures that have no males and reproduce by cloning can escape disease by drying up and floating away on the breeze, researchers have found. The rotifers reproduce by laying eggs, but without males, the eggs hatch without being fertilized, a process called parthenogenetic cloning. The offspring are exact genetic clones of their mothers. "Generally, when organisms lose males and start reproducing asexually, they go extinct relatively quickly afterwards," Chris Wilson, a doctoral student in neurobiology at Cornell University, told CBC Radio's As It Happens. Rotifers, though, have diversified into 450 different species and have survived for 30 million years reproducing only by parthenogenesis. This type of asexual reproduction is seen in nematode worms, and in some species of insects, crustaceans, reptiles and sharks. But reproduction exclusively by cloning is rare. Cloning is efficient because it essentially doubles the reproductive output of a species by eliminating the need for two parents. However, since the offspring are genetically identical to their mothers, a parasite or virus can wipe out a large population if it is genetically susceptible to it. Scientists think sex allows a species to swap and recombine genetic material in new ways and avoid such diseases. © CBC 2010

Keyword: Sexual Behavior; Evolution
Link ID: 13726 - Posted: 06.24.2010

By Jennifer Viegas Squeaker catfish of all ages communicate with each other by, you guessed it, squeaking, according to a new study in the journal BMC Biology. Previously it was thought that young fish had under-developed hearing organs and could not perceive sounds made by older fish. The findings add to the growing body of evidence that fish have complex communication systems and aren't always the strong, silent types. For the study, researchers studied the catfish Synodontis schoutedeni. This species rubs the spines of its pectoral fins into grooves on its shoulder, thus creating the squeak sound. By placing the fish in a combined fish tank and sound-proof chamber, the scientists were not only able to measure the produced sounds, but also how well each fish heard them. Young and old squeaker catfish were tested. "This study is the first to demonstrate that absolute hearing sensitivity changes as catfish grow up," said the University of Vienna's Walter Lechner. He added, "This contrasts with prior studies on the closely related goldfish and zebrafish, in which no such change could be observed. Furthermore, S. schoutedeni can detect sounds at all stages of development, again contrasting with previous findings." © 2009 Discovery Communications, LLC.

Keyword: Animal Communication; Language
Link ID: 13725 - Posted: 06.24.2010

By Emily Sohn There may be a simple way to ease the memory lapses and brain slips that typically accompany old age: Eat more blueberries. In a small study, older adults who drank a couple cups of blueberry juice a day improved their scores on a learning and memory task by 20 percent. Studies in animals have linked blueberries with brain function, but this is one of the first such studies in people. The results, while still preliminary, suggest that blueberries might just live up to their reputation as "superfoods." Among other health benefits, adding the tasty little, blue marbles to your diet could help slow the march of memory decline and possibly even prevent memories from slipping in the first place. "We're getting the first signal in humans that this might work," said Robert Krikorian, a neuropsychologist at the University of Cincinnati in Ohio. "There's so much research now suggesting that fruits and vegetables are beneficial. I don't have any qualms about recommending that people eat blueberries." The case for blueberries has been building for more than a decade. In animal studies, older individuals that consume blueberry extract improve their performance on memory tasks, sometimes to the point of being just as sharp as their younger counterparts. © 2009 Discovery Communications, LLC

Keyword: Learning & Memory
Link ID: 13724 - Posted: 06.24.2010

by Ewen Callaway In a feat of cellular alchemy, connective tissue from a mouse's tail has been transformed directly into working brain cells. Ordinarily, so drastic a makeover would require the creation of so-called induced pluripotent stem (iPS) cells and then turning these into neurons, an inefficient process that can take weeks. Marius Wernig and colleagues at Stanford University in California discovered that inserting a cocktail of three genes into fibroblasts turns them directly into neurons in just days. "The real surprise was that this conversion is extremely efficient," he says. By many indications, these neurons are the real deal. Under a microscope, they look like a kind of mouse brain cell found in the cortex and they can form synapses to send and receive signals from others. Wernig expects that the cells will integrate into a mouse's brain - an experiment that's in the works. If they do, cells produced using a similar process might one day be used to treat conditions such as Parkinson's disease in humans. Because such cells are derived from adult cells, not pluripotent cells – which have the potential to form a kind of tumour called a teratoma – they might be safer than iPS cells. © Copyright Reed Business Information Ltd.

Keyword: Stem Cells; Regeneration
Link ID: 13723 - Posted: 06.24.2010

By Katie Moisse You can tell a lot about a person by their face—even their political affiliation, new research claims. In a study published in the January 18 issue of PLoS One, subjects were able to accurately identify candidates from the 2004 and 2006 U.S. Senate elections as either Democrats or Republicans based on black-and-white photos of their faces. And subjects were even able to correctly identify college students as belonging to Democratic or Republican clubs based on their yearbook photos. To investigate the basis of these judgments, subjects were asked to rate photos of faces on a seven-point scale assessing personality traits such as assertiveness, maturity, likeability and trustworthiness. Subjects consistently associated Democrats with warmth (likeable and trustworthy) and Republicans with power (dominant and mature). These findings were independent of the gender of the person in the photo. The authors concluded that people possess "a general and imperfect" ability to infer political affiliation based on facial appearance, which is related to stereotypes about Democrat and Republican personalities. The ability to surmise other perceptually ambiguous traits, such as sexual orientation and religious group membership, has been reported in similar studies. © 2010 Scientific American,

Keyword: Emotions
Link ID: 13722 - Posted: 06.24.2010

By Marla Cone and Environmental Health News Children exposed in the womb to chemicals in cosmetics and fragrances are more likely to develop behavioral problems commonly found in children with attention deficit disorders, according to a study of New York City school-age children published Thursday. Scientists at Mount Sinai School of Medicine reported that mothers who had high levels of phthalates during their pregnancies were more likely to have children with poorer scores in the areas of attention, aggression and conduct. Children were 2.5 times more likely to have attention problems that were “clinically significant” if their mothers were among those highest exposed to phthalates, the study found. The types of behavior that increased are found in children with Attention Deficit Hyperactivity Disorder and other so-called disruptive behavior disorders. “More phthalates equaled more behavioral problems,” Stephanie Engel, a Mount Sinai associate professor of preventive medicine and lead author of the study, said in an interview Thursday. “For every increase of exposure, we saw an increase in frequency and severity of the symptoms.” The connection was only detected for the types of phthalates used in perfumes, shampoos, nail polishes, lotions, deodorants, hair sprays and other personal care products. No behavioral effects were found for the phthalates used in vinyl toys and other soft plastics. © 2010 Scientific American

Keyword: ADHD; Neurotoxins
Link ID: 13721 - Posted: 06.24.2010

By Susan Gaidos It could have been a scene from a sequel to Jurassic Park: Peering down at the tiny worms wriggling under the lens of her microscope, biologist Alexandra Bely witnessed a performance that hadn’t been played in nature in millions of years. The beastie was sprouting a second head. Actually, two-headed worms are common in Bely’s lab at the University of Maryland in College Park. But this specimen belongs to a species that had long ago lost the unusual regenerative ability. That species, Paranais litoralis, is part of an ancient family of worms called naidids that settle in the soft sediments alongside streams and ponds. Generally, if a sudden rush of water or a hungry predator causes a naidid to lose its head, it will simply grow another one. But some species that Bely and colleagues have studied, including Pa. litoralis, seem to have lost this power. So it surprised Bely to see that, with the right timing, the creature could regain its head-popping potential. “That’s very exciting, because it indicates that the ability to regenerate is still there, in a dormant state,” Bely says, “though it probably hasn’t been expressed or seen in millions of years.” Bely’s finding and other recent results have encouraged researchers who are trying to figure out why some animals can reconstruct their body parts while others can’t. Most species have the ability to regenerate some body parts, yet this talent is highly variable. © Society for Science & the Public 2000 - 2010

Keyword: Regeneration
Link ID: 13720 - Posted: 06.24.2010

By Greg Miller Chimpanzees have an aggressive reputation and often fight rather than share. Bonobos, on the other hand, are famously playful and friendly. A new study hints at a difference in how the two apes develop, suggesting that bonobos retain a youthful lack of social inhibition longer than chimpanzees do. Understanding how and why these two apes--the closest living relatives to humans--differ from each other could yield clues about how our own species evolved to be so social. Anatomical studies of ape skulls have suggested that bonobos' brains mature more slowly than those of chimps, says the lead author of the new study, Victoria Wobber, a graduate student in the lab of Harvard University primatologist Richard Wrangham. But no one had looked for corresponding differences in the development of social behaviors in the two apes, Wobber says. So she and colleagues conducted experiments on about 60 apes of various ages at the Tchimpounga Sanctuary in the Republic of the Congo and the Lola ya Bonobo sanctuary in the Democratic Republic of the Congo. In the first experiment, the researchers put a bowl of fruit in an enclosure and allowed pairs of age-matched chimps or bonobos to enter. The apes scored high marks for social tolerance if they shared the food, particularly if they came close together and ate from the bowl at the same time. Young animals of both species were good at sharing, the researchers found. Although older bonobos appeared to maintain their youthful tolerance, chimps tended to be less tolerant with age. In pairs of older chimps, the more dominant one often hogged all the food. And even when sharing occurred, two individuals rarely ate from the bowl at the same time. © 2010 American Association for the Advancement of Science.

Keyword: Development of the Brain; Evolution
Link ID: 13719 - Posted: 06.24.2010

by Ewen Callaway Ageing may cloud your financial judgement, thanks to "noise" in an area of the brain critical for predicting pay-offs, suggests a study of people who played an investment game in a brain scanner. Gregory Samanez-Larkin and Brian Knutson of Stanford University in California, scanned the brains of 110 men and women aged 19 to 85 with functional MRI as they played 100 rounds of a game in which they had to choose one of three possible investments. One was in a safe bond that always delivers $1, another was a stock twice as likely to pay off $10 than to lose $10. The third was a highly risky stock with those odds flipped. "What we're doing is trying to get closer and closer to real investing," Samanez-Larkin says. Shrewd investors will keep picking bonds until they figure out which is the profitable stock. The researchers found that volunteers between 67 and 85 took longer to figure this out than their younger counterparts. "When older adults are choosing risky assets they make more errors," says Samanez-Larkin. What's more activity in the striatum, a region critical to sensing reward, was more sporadic in these older volunteers – this area only lit up strongly in some rounds, whereas in younger volunteers activation was consistent. © Copyright Reed Business Information Ltd

Keyword: Alzheimers; Drug Abuse
Link ID: 13718 - Posted: 06.24.2010

THE brains of monkeys whose mothers had flu while pregnant resemble those of people with schizophrenia. The finding backs up studies in people that suggest flu in mothers-to-be affects the brain of the developing fetus. Previous research had found that the children of women who caught flu while pregnant are more likely to develop schizophrenia later in life. To investigate further, Sarah Short and Chris Coe at the University of Wisconsin, Madison, infected 12 pregnant rhesus monkeys with mild flu. Their 19 offspring seemed to develop normally. Yet MRI scans of the 1-year-old juveniles - equivalent in age to a 5 to 7-year-old human child - revealed that their brains had features similar to those seen in people with schizophrenia, including less grey matter in the cortex and enlarged ventricles. Monkeys whose mothers had not had flu did not have these features (Biological Psychiatry, DOI: 10.1016/j.biopsych.2009.11.026). The team will now monitor the monkeys for behaviour similar to that seen in schizophrenia. In the meantime, Coe advises would-be mothers to get seasonal flu shots. "The implication for people is that if women are planning to get pregnant it makes more sense being immunised in advance rather than risking having a bad flu infection when pregnant," Coe says. © Copyright Reed Business Information Ltd

Keyword: Schizophrenia
Link ID: 13717 - Posted: 06.24.2010

By Pam Rutherford Many of us struggle sometimes to put a name to a face, but what if you could recognise someone many years after seeing them for a moment? You know the woman crossing the street. But where from? Ah, she was one of the volunteers staffing the polling station where you voted several years before. You probably saw her for a couple of minutes. Several years ago. Sound like the kind of face you would place immediately? It is for Jennifer. She is a "super recogniser", someone with a significantly above average ability to place a face. In fact, she can almost never forget a face. She first noticed something might be unusual on holiday with her family when she spotted a very minor actor on a plane. Her family were disbelieving but she was proved right. But it really hit home at college that she was different from those around her. "I'd meet so many people in the first few weeks and I'd remember everyone no matter how brief the encounter. I'd then meet them at a party and they wouldn't remember me. I'd think: 'That person is SO fake, I can't believe they're pretending they don't remember me when we met for 30 seconds in the cafeteria three weeks ago.'" It doesn't matter if years have lapsed since seeing them. She describes seeing someone she saw a few times as child, on the subway, now over 20 years older with greying hair and dreadlocks and knowing exactly who she was. "People can get older but their faces look the same to me," says Jennifer. "They don't look different to me whether they're children or adults. I don't know why my mind is able to make the leap." It sounds like a neat party trick, or perhaps something useful in business, but it may mean more than that to scientists. Jennifer's ability may help scientists who are investigating people in the opposite position, those who suffer from the condition prosopagnosia, popularly known as face blindness. (C)BBC

Keyword: Attention
Link ID: 13716 - Posted: 01.28.2010

New mothers who are taking a common class of antidepressants may have a delay in lactation and need extra support to breastfeed, researchers say. The selective serotonin reuptake inhibitors or SSRI type of antidepressants such as Prozac and Paxil may be linked with a delay in the start of full milk secretion, according to a study to be published in the February issue of the Journal of Clinical Endocrinology & Metabolism. The body's production and regulation of the hormone serotonin is closely related to the ability of the breasts to secrete milk at the right time, said study co-author Nelson Horseman of the University of Cincinnati. While SSRI drugs can affect mood, emotion and sleep, "they may also impact serotonin regulation in the breast, placing new mothers at greater risk of a delay in the establishment of a full milk supply," he said in a release. In the study, researchers looked at the effects of SSRI on milk production in 431 new mothers. The average onset of lactation was 85.8 hours postpartum for the SSRI-treated mothers and 69.1 hours for mothers not treated with SSRI drugs, the team found. They defined a delay as 72 hours after the birth. 'Very helpful medications' "SSRI drugs are very helpful medications for many moms, so understanding and ameliorating difficulties moms experience can help them achieve their goals for breastfeeding their babies," said Horseman. © CBC 2010

Keyword: Depression
Link ID: 13715 - Posted: 06.24.2010

by Amanda Feilding and Paul Morrison THE effects of cannabis on mental health have attracted much attention over the years. As far back as the 19th century it was recognised that cannabis could induce a transient psychosis which mimics the symptoms of schizophrenia. Despite this, until the last decade or so, most psychiatrists regarded cannabis as essentially benign. This, however, is at odds with recent research which concludes that in a susceptible minority, cannabis use can push the brain towards long-term psychosis requiring mental health treatment. Susceptible young people who use cannabis increase their risk of developing a chronic psychotic disorder such as schizophrenia, and the more cannabis they consume, the higher the risk. Additionally, people with schizophrenia who have a history of cannabis use tend to go through their first breakdown up to five years earlier in life than those who do not use the drug. Psychotic patients who fail to give up cannabis experience more symptoms, more relapses and end up in hospital more often. These discoveries about the link between cannabis and psychosis have been widely reported in the media, often accompanied by warnings that street cannabis has risen in strength in recent years and therefore poses a major health risk to the susceptible minority. © Copyright Reed Business Information Ltd

Keyword: Drug Abuse; Schizophrenia
Link ID: 13714 - Posted: 06.24.2010

Children who write with both hands are more likely to struggle in school and have hyperactivity disorder symptoms, research suggests. A study by scientists from Imperial College London found ambidextrous children were twice as likely to struggle as their classmates. They were also more likely to have difficulties with language. Experts told Paediatrics journal the differences might be down to the brain's wiring. But they said much more work was needed to explore this. Lead researcher Dr Alina Rodriguez said: "Mixed-handedness is intriguing - we don't know why some people prefer to make use of both hands when most people use only one." Around one in every 100 people is ambidextrous, or mixed-handed. The study looked at nearly 8,000 children from Northern Finland, of whom 87 were mixed-handed. Mixed-handed children aged seven and eight were twice as likely as their right-handed peers to have difficulties with language and to perform poorly in school. When they reached 15 or 16, mixed-handed adolescents were also at twice the risk of having symptoms of Attention Deficit Hyperactivity Disorder (ADHD). And they tended to have more severe symptoms of ADHD than their right-handed schoolmates. They also reported having greater difficulties with language than those who were left or right-handed. This is in line with earlier studies that have linked mixed-handedness with dyslexia. Experts know that handedness is linked to the brain's left and right halves or hemispheres. Research has shown that where a person's natural preference is for using their right hand, the left hemisphere of their brain is more dominant, which is where the centre for language lies. Scientists have suggested that ADHD could be linked to having a weaker function in the right hemisphere of the brain. Dr Rodriguez said it was possible that brain differences might explain the findings. (C)BBC

Keyword: ADHD; Laterality
Link ID: 13713 - Posted: 01.26.2010

By Elizabeth Pennisi Bats and dolphins are about as different as mammals get. Yet, both home in on their prey by emitting sound waves and sensing the reflections, a process called echolocation. And a new study shows that in both groups the same protein evolved in the same way to make that possible. Researchers say it's surprising to discover a molecular convergence in these very distantly related groups of animals. The protein, called prestin, exists in all mammals and helps so-called outer hair cells in the inner ear amplify incoming sound waves. Because people with mutations in the prestin gene often can't hear high frequencies, Shuyi Zhang, an ecologist at East China Normal University (ECNU) wondered whether prestin had evolved to make possible the high-frequency hearing that bats use for echolocation. With student Liu Yang of ECNU, James Cotton and Stephen Rossiter of Queen Mary, University of London, and colleagues, he analyzed the sequence of the prestin gene in distantly related bats that had independently evolved echolocation. In 2008, the researchers discovered that the functional parts of prestin had come to look the same in both groups of bats but not in other bats that do not use echolocation, indicating convergent evolution of the protein. The team has now looked even farther afield, examining whether prestin in dolphins and other toothed whales has the same makeup. They sequenced the prestin gene in several dolphin species, in a sperm whale, and in baleen whales, which do not use echolocation, and then compared the sequences with those of bats. Fourteen sites had evolved to be exactly the same, six of which proved most likely to be due to convergent evolution, they report in the 26 January issue of Current Biology. © 2010 American Association for the Advancement of Science.

Keyword: Hearing; Genes & Behavior
Link ID: 13712 - Posted: 06.24.2010

By RANDOLPH E. SCHMID WASHINGTON – Little girls may learn to fear math from the women who are their earliest teachers. Despite gains in recent years, women still trail men in some areas of math achievement, and the question of why has provoked controversy. Now, a study of first- and second-graders suggests what may be part of the answer: Female elementary school teachers who are concerned about their own math skills could be passing that along to the little girls they teach. Young students tend to model themselves after adults of the same sex, and having a female teacher who is anxious about math may reinforce the stereotype that boys are better at math than girls, explained Sian L. Beilock, an associate professor in psychology at the University of Chicago. Beilock and colleagues studied 52 boys and 65 girls who in classes taught by 17 different teachers. Ninety percent of U.S. elementary school teachers are women, as were all of those in this study. Student math ability was not related to teacher math anxiety at the start of the school year, the researchers report in Tuesday's edition of Proceedings of the National Academy of Sciences. But by the end of the year, the more anxious teachers were about their own math skills, the more likely their female students — but not the boys — were to agree that "boys are good at math and girls are good at reading." © 2010 The Associated Press

Keyword: Sexual Behavior
Link ID: 13711 - Posted: 06.24.2010

by Bob Holmes Wild crows can recognise individual human faces and hold a grudge for years against people who have treated them badly. This ability – which may also exist in other wild animals – highlights how carefully some animals monitor the humans with whom they share living space. Field biologists have observed that crows seem to recognise them, and a few researchers have even gone to the extreme of wearing masks when capturing birds to band (or "ring") them, so that they could later observe the birds without upsetting them. However, it was unclear whether the birds distinguish people by their faces or by other distinctive features of dress, gait or behaviour. To find out, John Marzluff at the University of Washington in Seattle and colleagues donned a rubber caveman mask and then captured and banded wild American crows. Whenever a person wearing the same mask approached those crows later, the birds scolded them loudly. In contrast, they ignored the same person wearing a mask of former US Vice-President Dick Cheney, which had never been worn during banding. "Most of the time you walk right up to them and they don't care at all," says Marzluff. The birds' antipathy to the caveman mask has lasted more than three years, even though the crows have had no further bad experiences with people wearing it. The crows responded less strongly to other details of a person's dress, such as the presence of a hat or a coloured armband. © Copyright Reed Business Information Ltd.

Keyword: Evolution; Intelligence
Link ID: 13710 - Posted: 06.24.2010

Jessica Hamzelou, reporter Prion proteins have a bad reputation. The misfolded forms of this brain protein are responsible for a host of neurological diseases including, notoriously, variant Creutzfeldt-Jakob Disease (vCJD), which has been linked to eating contaminated beef. But what about the normal, correctly folded version of prion protein? Surely it must have a function in the brain? Neurologists still haven't figured out exactly what this is, but several pieces of evidence suggest that prions aren't all bad. The latest study, published in Nature Neuroscience, suggests that prions are important in maintaining the myelin sheath that surrounds nerve cells, enabling them to transmit nerve impulses rapidly. Adriano Aguzzi and his team at University Hospital of Zurich, Switzerland, bred mice lacking prion protein. They found that these mice developed a condition where their peripheral nerves, which connect the limbs to the central nervous system, lost much of their myelin coating. Although it's too early to say whether the finding can be applied to human disease, Aguzzi told Asian News International that he thinks "it is going to be interesting to see if prions play any role in demyelinating diseases that stem from the brain". This isn't the first time prions have been caught doing some good. Over the past 15 years, researchers have been noting that although mice without the prion protein don't develop prion disease - and can even be rescued from it - they end up with all sorts of other problems. © Copyright Reed Business Information Ltd.

Keyword: Prions
Link ID: 13709 - Posted: 06.24.2010

By Frederik Joelving You awake with a pounding heart and clammy hands. Relax, you think to yourself—it was just a bad dream. But are nightmares truly benign? Psychologists aren’t so sure. Although some continue to believe nightmares reduce psychological tensions by letting the brain act out its fears, recent research suggests that nocturnal torments are more likely to increase anxiety in waking life. In one study Australian researchers asked 624 high school students about their lives and nightmares during the past year and assessed their stress levels. It is well known that stressful experiences cause nightmares, but if night­mares serve to diffuse that tension, troubled sleepers should have an easier time coping with emotional ordeals. The study, published in the journal Dreaming, did not bear out that hypothesis: not only did nightmares not stave off anxiety, but people who reported being distressed about their dreams were even more likely to suffer from general anxiety than those who experienced an upsetting event such as the divorce of their parents. It is possible, however, that some-thing is going wrong in the brains of individuals who experience a lot of anxiety, so that normal emotional processing during dreaming fails, says Tore Nielsen, director of the Dream and Nightmare Laboratory at Sacred Heart Hospital in Montreal. But Nielsen’s most recent results, published in the Journal of Sleep Research last June, actually bolster the Australian findings. © 2010 Scientific American,

Keyword: Sleep; Emotions
Link ID: 13708 - Posted: 06.24.2010

Fresh research may help explain why regular exercise can improve brain power, say Cambridge scientists. The report, which was published in the Proceedings of the National Academy of Sciences, found mice which exercised performed better on memory tests. These mice also grew more new cells in a part of the brain linked to memory than those which did not exercise. The authors believe the new brain cells were behind the improvement in cognitive performance. The aim of the study, which was carried out by scientists from the Department of Experimental Psychology at the University of Cambridge and researchers at the National Institute on Aging in Baltimore, was to find out why exercise might improve brain function. Previous research had suggested that exercise helps mental performance in both people and animals. Studies had also shown that exercise increases the number of new brain cells in rodents. The new finding in this study is that mice which exercise are better able to distinguish between memories of similar things. The authors believe this is explained by the additional brain cells generated by exercise. The study was conducted on two groups of mice over a period of 105 days. The mice were trained to touch a box on a computer screen to get food pellets. One group were then allowed unlimited access to an exercise wheel. They ran over 20km (12 miles) a day on average. The control group were not able to exercise. Both groups were then repeatedly shown two boxes on a screen, one of which provided a treat when it was touched. The mice learned which box released the treat, and then the boxes were moved around. First the boxes were moved close together, which made it harder for the mice to remember which one to touch to get the food. The exercising mice did better on this task than the non-exercising mice. (C)BBC

Keyword: Learning & Memory
Link ID: 13707 - Posted: 01.25.2010