Arran Frood Smoking cannabis has long been associated with poor short-term memory, but a study now suggests that the strain of cannabis makes all the difference. In a test of short-term memory skills, only users of 'skunk'-type strains exhibited impaired recall when intoxicated, whereas people who smoked hashish or herbal cannabis blends performed equally well whether they were stoned or sober. The findings suggest that an ingredient more plentiful in some types of marijuana than in others may help to reduce the memory loss that some users suffer. The key difference between the types of cannabis is the ratio of two chemicals found in all strains. Tetrahydrocannabinol (THC) is the primary active ingredient, and is responsible for the effects associated with the classic 'high', including euphoria and giddiness but also anxiety and paranoia. The second chemical, cannabidiol, has more calming effects, and brain-imaging studies have shown that it can block the psychosis-inducing effects of THC2. Skunk-type strains of cannabis contain a higher ratio of THC to cannabidiol than do hashish or herbal types. Valerie Curran, a psychopharmacologist from University College London who led the latest study, says that if habitual users must partake they should be encouraged to use strains with higher levels of cannabidiol, rather than using skunk. She also argues that studying cannabidiol could provide insight into the mechanics of memory formation, and that it may have therapeutic benefits for disorders involving memory deficits. The findings are published in the British Journal of Psychiatry today1. marijuana leafLevels of THC in 'skunk' marijuana are higher than in other varieties. © 2010 Nature Publishing Group,

Keyword: Drug Abuse; Learning & Memory
Link ID: 14516 - Posted: 10.02.2010

By Rob Stein Scientists have invented an efficient way to produce apparently safe alternatives to human embryonic stem cells without destroying embryos, a long-sought step toward bypassing the moral morass surrounding one of the most promising fields in medicine. A team of researchers at the Harvard Stem Cell Institute in Boston published a series of experiments Thursday showing that synthetic biological signals can quickly reprogram ordinary skin cells into entities that appear virtually identical to embryonic stem cells. Moreover, the same strategy can then turn those cells into ones that could be used for transplants. "This is going to be very exciting to the research community," said Derrick J. Rossi of the Children's Hospital Boston, who led the research published in the journal Cell Stem Cell. "We now have an experimental paradigm for generating patient-specific cells highly efficiently and safely and also taking those cells to clinically useful cell types." Scientists hope stem cells will lead to cures for diabetes, Alzheimer's disease, spinal cord injuries, heart attacks and many other ailments because they can turn into almost any tissue in the body, potentially providing an invaluable source of cells to replace those damaged by disease or injury. But the cells can be obtained only by destroying days-old embryos. © 2010 The Washington Post Company

Keyword: Stem Cells; Regeneration
Link ID: 14515 - Posted: 10.02.2010

By NOAH SNYDER-MACKLER To the untrained eye, all geladas look alike. Complicating matters, they form some of the largest aggregations of any nonhuman primate. We have seen groups in excess of 1,000 individuals. Most days we want to find a specific monkey or group of monkeys. We do not tag, mark or radio-collar the geladas, though countless times I have wished to do so out of frustration. Fortunately my colleagues and I are trained for this. The leaders of our project, Thore Bergman and Jacinta Beehner from the University of Michigan, are especially adept at distinguishing individual gelada monkeys. There are the easy monkeys to identify, like Tail, the female with half of her tail missing. And then there are the hard ones, which make up a vast majority of our monkeys. To identify these individuals we look for subtle differences, like small scars or discolorations on their ears or face. This was tough when I first started last year, but after a month I was an expert at picking my specific monkey out of the group. Unfortunately, the ability to identify 180 individual geladas wasn’t stored into my long-term memory. This is my first week back, and I am having a terribly difficult time with the monkeys. I started by relearning the easy ones. Tail is still alive — one down, 179 to go. It will be a slow process, but I’m lucky to have some of the most experienced teachers here to help me — my research colleagues. Copyright 2010 The New York Times Company

Keyword: Evolution
Link ID: 14514 - Posted: 10.02.2010

by Anil Ananthaswamy When the going got tough in prehistoric East Africa, some of humanity's closest relatives went for bigger jaws, rather than bigger brains. Big mistake By some 30 million years ago, the primate upstarts had come to dominate the canopies of the once more lush tropical rainforests. For one particular group, this was a mere staging post. Before about 20 million years ago, east Africa boasted Amazon-like jungles that were a stable and plentiful home to our forebears, still swinging from the trees. Then the Earth moved, quite literally. A plume of magma started pushing up from beneath what is now northern Ethiopia. During the following 15 million years, two massive mountain ranges running north to south, each about 2 kilometres high, rose up out of the east African plateau. Saddled in the middle was the Great Rift Valley, a depression a kilometre above sea level. The mountains to the east deflected moisture-laden winds arriving from the Indian Ocean, and those in the west stopped similar winds from the Congo. Deprived of rain, the valley gradually began to change from lush rainforest to sparser savannah. For our African ancestors, living in the trees was no longer such a viable survival strategy. © Copyright Reed Business Information Ltd.

Keyword: Evolution
Link ID: 14513 - Posted: 10.02.2010

by Andy Coghlan For the first time, evidence has emerged of genetic mutations linked to attention-deficit hyperactivity disorder. But how strong is the link, and how far does the finding undermine claims that children with the condition are simply naughty kids, victims of bad parenting or driven to hyperactivity by dietary additives? What did the researchers do? A research team in the UK screened DNA across the entire genome from 366 children with ADHD and 1047 children without the condition for rare but massive regions of DNA that were either missing from where they should be or duplicated. They looked for these abnormalities, called copy-number variants or CNVs, because some had been linked previously with other psychiatric disorders, including schizophrenia and autism. And what was the result? They found that 16 per cent of the children with ADHD had abnormally high numbers of CNVs, double the 8 per cent of normal children who had them: the ADHD children had double the risk of carrying these genetic abnormalities. Is that a big deal? "We have the first scientific evidence of a direct genetic link," said their leader, Anita Thapar of Cardiff University, at a press conference in London. © Copyright Reed Business Information Ltd.

Keyword: ADHD; Genes & Behavior
Link ID: 14512 - Posted: 10.02.2010

MIGRATORY bats have smaller brains than their stay-at-home cousins, suggesting they cannot afford the luxury of lugging large, energetically expensive brains on long journeys. The discovery might also be true for birds. The brains of migratory birds tend to be smaller than those of similar-sized species that do not migrate. But biologists have been unsure whether this is because non-migratory birds need larger brains to cope with the challenges of finding food through the changing seasons, or because migrators need to pare down their weight for travel. Larger brains burn more energy and their extra weight makes flight more costly too. Liam McGuire, an ecologist at the University of Western Ontario in London, Canada, and his colleague John Ratcliffe of the University of Southern Denmark in Odense turned to bats for the answer. Non-migratory species of bat typically hibernate through the winter months, so they do not need to adjust their foraging behaviour to survive. Yet the researchers still found that migratory bats had smaller brains than non-migratory ones (Biology Letters, DOI: 10.1098/rsbl.2010.0744). Other factors may also be important in birds, which show a greater difference in brain size than bats. But the finding suggests that the need to reduce weight in migrators is a sufficient evolutionary force to drive some of the difference. Issue 2780 of New Scientist magazine © Copyright Reed Business Information Ltd.

Keyword: Evolution; Animal Migration
Link ID: 14511 - Posted: 10.02.2010

By GARDINER HARRIS Infant sleep positioners that are used to keep babies on their backs and protect them from sudden infant death syndrome have led 12 children to suffocate in the past 13 years and should no longer be used, federal officials said Wednesday. Officials warned against using any products that have extensive foam, memory foam or significant cushioning in cribs. Most of the infants suffocated after rolling from a side position to a stomach position. In addition to the reported deaths, the government has received dozens of reports of infants who were placed on their backs or sides in sleep positioners, only to be found later in potentially hazardous positions within or next to the sleep positioners. The two main types of infant sleep positioners are flat mats with side bolsters or inclined mats with side bolsters. Both types of sleep positioners typically claim to help keep infants on their backs and reduce the risk of sudden infant death syndrome, or SIDS, but the Food and Drug Administration has never approved these products as safe. And the government said it was unaware of any scientific studies demonstrating that infant positioners prevented death or were proven to prevent suffocation or other life-threatening harm. Copyright 2010 The New York Times Company

Keyword: Sleep
Link ID: 14510 - Posted: 09.30.2010

By Tina Hesman Saey The brain almost always has a plan B, even when deciding which hand to use to press a button, a new study finds. A part of the brain called the left posterior parietal cortex plans button-pressing movements for both hands simultaneously, shows the study, published online September 27 in the Proceedings of the National Academy of Sciences. After a very brief neural tussle, one hand wins the competition and the other’s movement is suppressed, Flavio Oliveira, a neuroscientist at the University of California, Berkeley, and his colleagues demonstrate. Scientists actually know very little about how decisions such as which hand to use for a task are made in the brain, says Scott Frey, a cognitive neuroscientist at the University of Oregon in Eugene. While he may quibble with some of the details of the new study, “It helps to address a pretty blatant gap in the literature and it does it in an elegant way,” he says. “I think it’s one we’re going to be citing for a long time.” Oliveira and his collaborators studied right-handed people, as most such studies do. The volunteers placed their hands on a table containing a motion-tracking system. When a target was illuminated, the participants were supposed to reach as quickly as possible to hit the target. At first the volunteers were instructed to use only the right hand or left hand for the task. Then the participants were given a choice of which hand to use. Having to decide slowed the volunteers’ reaction times by about 30 milliseconds, especially when the target was about equidistant from both hands. The participants reached for an equidistant target more often with their right hands. © Society for Science & the Public 2000 - 2010

Keyword: Attention
Link ID: 14509 - Posted: 09.30.2010

By Bruce Bower Rhesus monkeys typically don’t check themselves out in a mirror — unless they’re wearing funky acrylic forehead blocks attached to hair-thin electrodes implanted in their brains. Given that fashion-forward apparel, these monkeys avidly use mirrors to examine and groom their heads and to inspect hard-to-see body areas, say neuroscientist Luis Populin of the University of Wisconsin–Madison and his colleagues. Animals with head implants sometimes turned themselves upside down or adjusted mirrors to get a better view of out-of-the-way body parts, the scientists report in a paper published online September 29 in PLoS ONE. “Rhesus monkeys recognize themselves in the mirror and have some form of self-awareness,” Populin holds. As in previous studies, monkeys with colored marks on their faces failed to inspect the marks when provided with mirrors and sometimes made aggressive moves as if the marked reflection were another monkey. Researchers generally regard such behavior as showing a lack of self-awareness. Unlike facial marks, though, implanted head devices presented monkeys with a bodily change striking enough to trigger self-inspection with a mirror, Populin proposes. “It is hard to say what is going on, as the head implant is not only seen but felt by monkeys,” remarks psychologist Frans de Waal of Emory University in Atlanta. This new evidence supports the idea that monkeys recognize their own reflections as special and don’t misidentify the images as other monkeys, he says, even if it doesn’t establish that the animals have a concept of self (SN: 7/23/05, p. 53). © Society for Science & the Public 2000 - 2010

Keyword: Attention; Intelligence
Link ID: 14508 - Posted: 09.30.2010

by Michael Marshall, Amsterdam AN EXPECTANT silence has descended on the small room in the Royal Netherlands Academy of Arts and Sciences in Amsterdam. Alan Grafen, a theoretical biologist from the University of Oxford, is taking his time to set up his presentation. When he's ready, he denounces three of his colleagues as "unscholarly" and "transparently wrong", and wonders what could have led such "talented, honest biologists" to be so "misguided". It's day one of a meeting on the evolution of conflict and cooperation, and exchanges are fierce. At stake is one of the pillars of modern evolutionary biology: the theory of inclusive fitness, which explains how altruistic behaviour can spread through a population. Altruism, in this context, refers to any behaviour which helps the chances of survival of others at the expense of the altruistic individual. Honeybees, which sting intruders to protect their hive and sign their own death warrant in the process, are a classic example. The conference is the latest stage of a controversy that has been raging over the work of three Harvard University scientists: mathematical biologists Martin Nowak and Corina Tarnita, and social insect guru and father of sociobiology Edward O. Wilson. Last month, they published a paper in Nature attacking inclusive fitness (vol 466, p 1057). The details of their attack are technical and mathematical, but the consequences could be far-reaching. They say inclusive fitness is irrelevant to the real world and want to replace it with a series of equations that could describe the evolution of cooperation in far more detail than ever before. © Copyright Reed Business Information Ltd.

Keyword: Evolution
Link ID: 14507 - Posted: 09.30.2010

By Jeremy Laurance, Health Editor Parents of children who cannot concentrate, are prone to fidget and act impulsively may for the first time be able to escape criticism of their child-rearing skills, after scientists announced that attention deficit hyperactivity disorder (ADHD) is a genetic condition. One in 50 children are affected by the disorder, which attracts disapproving looks and frequent scolding from people convinced that the bad behaviour is due to poor parenting, too much sugar or too many additives in the child's diet. Children with ADHD are impulsive and have an inability to focus, which causes difficulties at home and school, placing immense strain on their families. The burden has been aggravated by the stigma attached to the disorder which attributes responsibility to the parents. Now scientists from Cardiff University say the origin of the behaviour is in the genes. They compared the DNA of two groups of children with and without ADHD and have discovered differences between them which provide the first direct evidence of a genetic cause. Anita Thapar, professor of child and adolescent psychiatry at Cardiff University, said: "We are really excited by these findings. We have known ADHD runs in families but this is the first evidence of a direct genetic link. We hope these findings will help overcome the stigma associated with ADHD. ©independent.co.uk

Keyword: ADHD; Genes & Behavior
Link ID: 14506 - Posted: 09.30.2010

By Craig H. Kinsley and Elizabeth A. Meyer It seems that weekly we hear about some professional athlete who sullies himself and his sport through abuse of steroids. The melodrama unfolds, careers and statistics are brought low and asterisked, and everyone bemoans another fallen competitor. Yet there are millions of cases of steroid use that occur daily with barely a second thought: Millions of women take birth control pills, blithely unaware that their effects may be subtly seeping into and modulating brain structure and activity. It is a huge experiment whose resolution will not be known for a while, but a new study in the journal Brain Research demonstrates that the effects are likely to be dramatic. It found that birth control pills have structural effects on regions of the brain that govern higher-order cognitive activities, suggesting that a woman on birth control pills may literally not be herself -- or is herself, on steroids. The human brain is a remarkable structure, not least because of its seemingly infinite capacity for change, adapting millisecond by millisecond. Indeed, a structure with tens of billions of neurons, each of which has the ability to elaborate and branch and become more complex, while changing its activity in the process, is the very definition of change. This so-called neuroplasticity is a hallmark of the nervous system. It can, however, be augmented, boosted, by artificial means, and if we are not careful, the brain may go all catawampus. Steroid hormones, which are excreted by endocrine organs such as testes and ovaries, flow in abundance throughout the bloodstream, reach target organs and structures, and exert powerful effects on them. To wit, the cock’s comb, the buck’s antlers, the lion’s mane, the blood-engorged uterus. © 2010 Scientific American,

Keyword: Hormones & Behavior; Learning & Memory
Link ID: 14505 - Posted: 09.30.2010

by Miriam Frankel Would you push someone in front of a train if that would save five others? Probably not if you're on an antidepressant that raises your serotonin levels. Increased serotonin makes us less willing to hurt or punish other people, even if it's for the "greater good", a study has found. To test the effect of antidepressants on moral judgements, Molly Crockett and her team at the University of Cambridge presented 24 healthy volunteers with a moral dilemma while they were under the influence of the antidepressant citalopram – a selective serotonin reuptake inhibitor (SSRI), which increases brain serotonin levels. The participants given citalopram were about 10 per cent less willing to inflict harm on someone in order to benefit others compared with those given a placebo. The volunteers also played a game in which they were asked to accept or decline another player's offer of a share of a sum of money. If they accepted the offer, each player kept their share. If they refused, both players were left empty-handed. People with raised levels of serotonin were more likely to accept a stingy offer, rather than punishing the other player's greed by refusing it. Crockett points out that antidepressants are the most widely prescribed class of drugs in the US and that it is therefore important to investigate their effects on users' social behaviour and moral judgement. Journal reference: Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.1009396107 © Copyright Reed Business Information Ltd.

Keyword: Depression; Aggression
Link ID: 14504 - Posted: 09.28.2010

by Andy Coghlan Within two years, cocaine addicts desperate to kick the habit could take part in a pioneering trial of a gene therapy that gives them extra copies of a gene primed to mop up the drug. The therapy will be combined with a new vaccine that stops cocaine affecting the brain. The idea is that if you get no kick from the drug, you'll be less likely to get hooked again if you relapse. The gene in question makes a fast-acting version of butyrylcholinesterase, a natural human enzyme which destroys cocaine. Giving multiple copies of it to addicts would prevent them getting a high from the drug while they try to quit. The therapy should work if experiments in rats are anything to go by – treated rats didn't indulge in cocaine-seeking activity for up to a year. Just a single relapse within a year of giving up cocaine prevents 90 per cent of addicts staying clean, says Stephen Brimijoin of the Mayo Clinic in Rochester, Minnesota. Last week he received a grant from the US National Institute on Drug Abuse to investigate the potential for human trials and will be presenting his work this November in San Diego at the 2010 annual meeting of the Society for Neuroscience. Brimijoin uses harmless cold-related viruses to deliver the gene into rat cells. The gene is taken up mostly by liver cells, where it produces high but harmless quantities of the enzyme for at least a year. © Copyright Reed Business Information Ltd.

Keyword: Drug Abuse
Link ID: 14503 - Posted: 09.28.2010

Sleepless and sedentary? Instead of counting sheep in a field, try running through a meadow. Experts agree that an aerobic exercise routine during the day can keep you from tossing and turning at night, even if they're not sure why. "The bottom line is we really don't know why people tell us that exercise helps them sleep," said Dr. David Davila of the National Sleep Foundation. "But if people are normally active, reaching their aerobic goals, chances are they will sleep the right amount for what they need." Davila, who practices sleep medicine in Little Rock, Arkansas, said the low-grade sleep deprivation suffered by many time-pressed, under-rested Americans has a cumulative effect. "People have more car accidents and what they call 'presentee-ism', or poor performance, at work," he said. "There are fallouts for the average person." But evidence is emerging that aerobic exercise can offer relief from insomnia. A recent study at Northwestern University in Chicago, Illinois tracked 23 previously sedentary adults, primarily women 55 and older, who had difficulty falling or staying asleep. Copyright 2010 Thomson Reuters.

Keyword: Sleep
Link ID: 14502 - Posted: 09.28.2010

Content provided by AFP High estrogen levels in women while they are ovulating may be directly responsible for sluggishness or problems concentrating, a Canadian study released Friday has found. Researchers at Concordia University's Center for Studies in Behavioral Neurobiology in Montreal linked high estrogen levels in laboratory rats to an inability to pay attention and learn. These high levels have also been shown to interfere with women's ability to pay attention, but the study, to be published in the journal Brain and Cognition, is the first to show "how this impediment can be due to a direct effect of the hormone on mature brain structures," said a statement. Both humans and rodents have similar brain physiology. "Although estrogen is known to play a significant role in learning and memory, there has been no clear consensus on its effect," said study lead author Wayne Brake. "Our findings...show conclusively that high estrogen levels inhibit the cognitive ability in female rodents." Researchers repeatedly exposed rats to a tone, with no consequences. Once they became used to it and ignored it, another stimulus was linked to the tone. © 2010 Discovery Communications, LLC.

Keyword: Hormones & Behavior; Learning & Memory
Link ID: 14501 - Posted: 09.28.2010

By KATHERINE BOUTON What can we learn from the bees? Honeybees practice a kind of consensus democracy similar to what happens at a New England town meeting, says Thomas D. Seeley, author of “Honeybee Democracy.” A group comes to a decision through a consideration of options and a process of elimination. The bees are making a life-and-death decision: where to establish a new hive. Choosing a site that is too exposed, too small or too close to the ground can be fatal. Swarms don’t always do it right, but they do succeed a remarkable amount of the time, with 10,000 or more bees following the advice and signals of a few hundred leaders to re-establish themselves in a new location every spring. Along the way they have to make sure the precious queen, fatter and more sluggish than the others and prone to take a rest stop, is not lost. Dr. Seeley, professor and chairman in the department of neurobiology and behavior at Cornell University, makes a good-faith case for the effectiveness of bee-management style as applied to humans, but I couldn’t help suspecting that it might have been at the urging of his publisher. Bees and ants are the management model of choice just now, and books like “The Smart Swarm,” by Peter Miller, a senior editor at National Geographic, are quite admired in the business world. But as Dr. Seeley himself acknowledges, consensus democracy requires a like-minded electorate, and how often do we get that in real life? Copyright 2010 The New York Times Company

Keyword: Animal Communication; Language
Link ID: 14500 - Posted: 09.28.2010

By SINDYA N. BHANOO In the animal kingdom, it is common for males to have ornamentation, like bright feathers, to impress females of their species, but a newly identified species of dancing flies found in Japan adds something new to the game of sexual display. The ornamentation, a protrusion shaped like a boxing glove, often appears on just one of the fly’s front legs. The flies were found in the forested regions of Mount Fuji. While some males had the ornament on both legs, and some on neither, many had it on just one leg. The researchers describe their finding in the journal Biology Letters. “One struggles to explain why they are asymmetric — it could mean that this thing sits down on a log and sticks one leg up in the air to attract females,” said Adrian Plant, a taxonomist at the National Museum of Wales and one of the study’s authors. “We need more in-the-field live observations of the insects.” Of the 33 male flies collected, 14 had one ornamented leg, and the remaining had either two or none. The fact that so many were asymmetric led the researchers to believe that it was more than a freak of nature. What does seem clear is that the boxing glove detracts from the insect’s ability to fly efficiently, which adds to the idea that its function is to attract females. “It’s just like having a wild hairdo,” Dr. Plant said. Copyright 2010 The New York Times Company

Keyword: Sexual Behavior; Evolution
Link ID: 14499 - Posted: 09.28.2010

By Judy Foreman It’s one of the more puzzling observations in medicine: The vast majority of chronic pain patients are women. Women suffer disproportionately from irritable bowel syndrome, fibromyalgia, headaches (especially migraines), pain caused by damage to the nervous system, osteoarthritis, jaw problems like TMJ, and much more. Women also report more acute pain than men after the same common surgeries. One tiny piece of the pain puzzle illustrates just how complex the interplay among sex, genetics, and response to medications can be. In 2003, Jeffrey Mogil, a pain geneticist who studies rodents at McGill University, and Roger Fillingim, a psychologist and human pain researcher at the University of Florida, joined forces to test a prediction of Mogil’s: That redheaded women, but not men (redheaded or otherwise) would respond especially well to the pain-reliever drug pentazocine, or Talwin. Researchers already knew that there are significant sex differences in responsiveness to opioid drugs, or narcotics, in both mice and people. For both, certain opioid receptors in the nervous system act like magnets to pain-reducing opioids, whether pumped out naturally by the body or taken as drugs. Using fancy genetic mapping, Mogil, the mouse guy, and Fillingim, the people person, found that one particular receptor gene called Mc1R may hold the key to part of the differences in pain processing. © 2010 NY Times Co.

Keyword: Pain & Touch; Sexual Behavior
Link ID: 14498 - Posted: 09.27.2010

By Rosamond Hutt, PA Migraine sufferers were offered new hope today after researchers identified a faulty gene responsible for the debilitating headaches. The finding could lead to better treatment and improve the quality of life for the one in five people who have the neurological disorder. Scientists at the University of Oxford along with colleagues in Canada took DNA samples from migraines sufferers and their families. They found that if a gene called Tresk is defective it can trigger pain nerves in the brain and cause a severe headache. The discovery explains why people in the same family often suffer from the condition and could lead to new drugs that can switch off the pain. Dr Zameel Cader, from the Medical Research Council's Functional Genomics Unit at the University of Oxford, said: "We have now made a major step forward in our understanding of why people suffer with migraine and how in certain cases, your family can literally give you a headache. "Previous studies have identified parts of our DNA that increase the risk in the general population but have not found genes which can be directly responsible for common migraine. ©independent.co.uk

Keyword: Pain & Touch; Genes & Behavior
Link ID: 14497 - Posted: 09.27.2010