by Carl Zimmer Teenagers are a puzzle, and not just to their parents. When kids pass from childhood to adolescence their mortality rate doubles, despite the fact that teenagers are stronger and faster than children as well as more resistant to disease. Parents and scientists alike abound with explanations. It is tempting to put it down to plain stupidity: Teenagers have not yet learned how to make good choices. But that is simply not true. Psychologists have found that teenagers are about as adept as adults at recognizing the risks of dangerous behavior. Something else is at work. Scientists are finally figuring out what that “something” is. Our brains have networks of neurons that weigh the costs and benefits of potential actions. Together these networks calculate how valuable things are and how far we’ll go to get them, making judgments in hundredths of a second, far from our conscious awareness. Recent research reveals that teen brains go awry because they weigh those consequences in peculiar ways. Some of the most telling insight into the adolescent mind comes not from humans but from rats. Around seven weeks after birth, rats hit puberty and begin to act a lot like human teens. They start spending less time with their parents and more with other adolescent rats; they become more curious about new experiences and increasingly explore their world. Teenage rats also develop new desires. It’s not just that they get interested in sex but also that their landscape of pleasure goes through an upheaval. Miriam Schneider, a behavioral pharmacologist who studies adolescence at the University of Heidelberg, and her colleagues recently documented this shift. © 2011, Kalmbach Publishing Co.

Keyword: Development of the Brain
Link ID: 15135 - Posted: 03.26.2011

Matt Kaplan It seems that the constant threat of predation could have a more subtle effect on prey animals than first thought. Female birds that are exposed to predators while they are ovulating produce smaller offspring than unexposed females, researchers have found. The chicks may be smaller, but surprisingly, their wings grow faster and longer than those of chicks from unexposed mothers — an adaptation that might make them better at avoiding predators in flight. The mere presence of a predator can change the behaviour of prey animals. Numerous studies show that birds which are frequently presented with predators increase their nest-defence behaviours and usher their youngsters out of the nest faster, presumably to stop them from being sitting ducks. Yet a new study by Swiss ecologists suggests that predator effects could go beyond behaviour, to physiology. In a previous study in 20051, when ovulating female barn swallows (Hirundo rustica) were presented with models of predators, researchers found that their eggs contained higher than normal levels of corticosterone, a stress hormone. A follow-up examination showed that increased corticosterone reduced egg hatchability and led to fledglings being smaller. However, no one was sure whether this was simply the negative effects of stress or an adaptive response to help offspring cope better with intense predator presence. Keen to tease apart this problem, evolutionary ecologists Michael Coslovsky and Heinz Richner at the University of Bern in Switzerland studied a natural population of ovulating great tits (Parus major) nesting in Bremgartenwald forest near Bern. © 2011 Nature Publishing Group,

Keyword: Stress
Link ID: 15134 - Posted: 03.26.2011

Helen Thomson, biomedical news editor A paralysed woman was still able to accurately control a computer cursor with her thoughts 1000 days after having a tiny electronic device implanted in her brain, say the researchers who devised the system. The achievement demonstrates the longevity of brain-machine implants. The woman, for whom the researchers use the pseudonym S3, had a brainstem stroke in the mid-1990s that caused tetraplegia - paralysis of all four limbs and the vocal cords. In 2005, researchers from Brown University in Providence, Rhode Island, the Providence VA Medical Center and Massachusetts General Hospital in Boston implanted a tiny silicon electrode array the size of a small aspirin into S3's brain to help her communicate better with the outside world. The electrode array is part of the team's BrainGate system, which includes a combination of hardware and software that directly senses the electrical signals produced by neurons in the brain which control the planning of movement. The electrode decodes these signals to allow people with paralysis to control external devices such as computers, wheelchairs and bionic limbs. In a study just published, the researchers say that in 2008 - 1000 days after implantation - S3 proved the durability of the device by performing two different "point-and-click" tasks by thinking about moving a cursor with her hand. © Copyright Reed Business Information Ltd.

Keyword: Robotics
Link ID: 15133 - Posted: 03.26.2011

by Jacob Aron The latest generation of 3D technology has seen mixed success at the cinema, and 3D TVs are yet to establish themselves in the living room. Perhaps the true home of 3D is on mobile devices, where you don't even need special glasses. New Scientist takes a look at the future of 3D on the move. How can you have 3D without glasses? Simple – you do it all the time. We perceive the world in three dimensions because our eyes see two slightly different images and our brain interprets the difference as depth. Films or games displayed on an ordinary 2D screen don't contain any of that depth information, so we perceive them as flat surfaces. Traditional 3D screens add depth information back in by simultaneously displaying or rapidly alternating between two images, relying on viewing glasses to show the separate images to each eye. The red and cyan filters of the original 3D specs have now been replaced by the polarised light systems used in cinemas or active shutter glasses for 3D TVs, but the principle is much the same. Everyone would like to get rid of those 3D glasses, which is why screen manufacturers are researching two other techniques. Parallax barriers add a slotted barrier in front of the screen: each slot reveals a thin strip of the screen to one eye while the adjacent barrier blocks it from the other, so that all the slots together create separate images for each eye. Another technology, lenticular lenses, achieves the same effect with columns of bumpy lenses that redirect light to each eye – you might have once owned a ruler that used a very basic version to make moving or 3D images. © Copyright Reed Business Information Ltd.

Keyword: Vision
Link ID: 15132 - Posted: 03.26.2011

By Laura Sanders When courting, male mice lacking the chemical messenger serotonin don’t seem to care whether the object of their affection is female. Mice without the neurotransmitter no longer eschew the smells of other males, wooing them instead with squeaky love songs and attempts to mount them, researchers report online March 23 in Nature. Serotonin’s surprise role in mouse courtship may lead to a deeper understanding of how brain cells control a complex behavior. “Nobody thought that serotonin could be involved in this kind of sexual preference,” says study coauthor Zhou-Feng Chen of Washington University School of Medicine in St. Louis. Scientists emphasize that the male-male courtship seen in the lab isn’t equivalent to human homosexuality. And what, if anything, serotonin has anything to do with human sexual behavior is still an open question. “We have to be cautious because this is work done in mice,” Chen says. “I would be extremely careful to extrapolate these results into humans. We just don’t know much about this.” In the study, male mice that were genetically engineered to lack serotonin-producing brain cells still courted females. But when given the choice between males or females, these mice no longer reliably chose females over males. In tests where both a male and a female mating partner were present, nearly half of the serotonin-lacking males mounted the male first, report researchers led by Yi Rao of the National Institute of Biological Sciences and Peking University in Beijing. © Society for Science & the Public 2000 - 2011

Keyword: Sexual Behavior
Link ID: 15131 - Posted: 03.24.2011

by Shanta Barley Female hamadryas baboons may be vulnerable to a form of domestic violence from which they feel unable to escape – even if they have the opportunity. Most large papionin monkeys – a group including macaques, baboons and mandrills – rely on wandering males to disperse genes through the population. But studies suggest that gene flow through populations of hamadryas baboons (Papio hamadryas) in north-east Africa is mainly through females – even though males keep tight control of them and punish wanderers through vicious biting. In 1968, biologist Hans Kummer suggested that females move when they are abducted by another male – but only now have biologists observed such abductions. Mathew Pines at the Filoha Hamadryas Project in Addis Ababa, Ethiopia, witnessed three abductions between 2007 and 2009. Each time, the original male embarked on an often bloody rescue mission to locate and retrieve the female. Larissa Swedell at the City University of New York, Pines's co-author on the new study, speculates that abduction is not considered a "fair" way to gain a new female, and so the loss isn't accepted by the original male. The rescue missions were helped by the females, who willingly returned to the rescuer despite a history of violent treatment by that male. "The bond is so strong that a female will run to her male when she is frightened, even if he is the source of the threat," says Swedell. © Copyright Reed Business Information Ltd.

Keyword: Aggression; Sexual Behavior
Link ID: 15130 - Posted: 03.24.2011

By Nathan Seppa Using brain surgery to insert replacement genes, doctors can alleviate some movement problems in people with Parkinson’s disease. While not all of the gene therapy recipients in a new study improved, the group on average registered tangible gains after getting a gene that revs up production of a much-needed neurotransmitter, researchers report in an upcoming issue of Lancet Neurology. Notably, none of the patients had significant side effects attributable to the therapy. “The pendulum on gene therapy has really swung back and forth,” says study coauthor Matthew During, a physician and neuroscientist at Ohio State University in Columbus. “It was enormously hyped at first.” But the death of a patient in Philadelphia in 1999 and the appearance of leukemia in children in France getting gene therapy for an immune disorder — leading to a temporary suspension of trials in 2003 — stalled the research. “The field languished for a while,” During says. But he and his colleagues have continued to pursue the technology, using a disabled, nonpathogenic virus as the delivery vehicle for potentially useful genes. To treat Parkinson’s disease, the team has targeted a troublesome part of the brain where signaling gets obstructed in patients with the neurological disorder. In the new study, the researchers randomly assigned 16 patients with advanced Parkinson’s to undergo an operation to install gene replacements; 21 similar patients got sham surgery and received no genes. Neither group was told which operation they were getting. © Society for Science & the Public 2000 - 2011

Keyword: Parkinsons; Genes & Behavior
Link ID: 15129 - Posted: 03.24.2011

by Ferris Jabr A handful of people around the world have never known the meaning of physical pain – not because they live incredibly sheltered lives, but because their nerves lack a crucial ion channel that helps transmit signals between adjacent nerve cells. A new study reveals that our sense of smell depends on this same protein gate, establishing a previously unrecognised link between the perception of pain and scent. Jan Weiss of the University of Saarland School of Medicine in Homburg, Germany, and his colleagues recruited three people who cannot feel pain because they have a rare condition known as congenital analgesia. Weiss wanted to know whether people with this disorder have difficulty with other senses. The trio of participants – two of whom were siblings – could see and hear well and had never complained about a lousy sense of smell, but the researchers decided to put their noses to the test anyway. When the participants sniffed cotton wool pads soaked in balsamic vinegar, orange, mint, perfume and coffee, they failed to identify any of the odours. In contrast, nine healthy volunteers and the siblings' parents performed just fine, breathing deeply from the pleasant orange and mint scents and turning sharply away from the vinegar. Weiss and his team already knew that people who cannot experience physical pain usually lack a sodium ion channel called Nav1.7 in the membranes of nerve cells in the dorsal root ganglion and in the ganglia that are part of the autonomic nervous system, and wondered whether this loss could also explain the smelling problems. To find out, they examined tissue samples taken from the nose and olfactory system of normal people during surgery. The examinations revealed Nav1.7 channels in the cell membranes of the neurons that stipple these tissues. © Copyright Reed Business Information Ltd.

Keyword: Pain & Touch; Chemical Senses (Smell & Taste)
Link ID: 15128 - Posted: 03.24.2011

By Daniela Schiller and David Carmel Think about the last time you got bored with the TV channel you were watching and decided to change it with the remote control. Or a time you grabbed a magazine off a newsstand, or raised a hand to hail a taxi. As we go about our daily lives, we constantly make choices to act in certain ways. We all believe we exercise free will in such actions – we decide what to do and when to do it. Free will, however, becomes more complicated when you try to think how it can arise from brain activity. Do we control our neurons or do they control us? If everything we do starts in the brain, what kind of neural activity would reflect free choice? And how would you feel about your free will if we were to tell you that neuroscientists can look at your brain activity, and tell that you are about to make a decision to move – and that they could do this a whole second and a half before you yourself became aware of your own choice? Scientists from UCLA and Harvard -- Itzhak Fried, Roy Mukamel and Gabriel Kreiman -- have taken an audacious step in the search for free will, reported in a new article in the journal Neuron. They used a powerful tool – intracranial recording – to find neurons in the human brain whose activity predicts decisions to make a movement, challenging conventional notions of free will. Fried is one of a handful of neurosurgeons in the world who perform the delicate procedure of inserting electrodes into a living human brain, and using them to record activity from individual neurons. He does this to pin down the source of debilitating seizures in the brains of epileptic patients. Once he locates the part of the patients’ brains that sparks off the seizures, he can remove it, pulling the plug on their neuronal electrical storms. © 2011 Scientific American,

Keyword: Attention
Link ID: 15127 - Posted: 03.24.2011

By Carolyn Y. Johnson Amir Lahav peered into the incubators where his premature twins slept, their frighteningly tiny bodies entwined with tubes and wires. This was a world very different from the womb, he thought. It wasn’t just the ventilators and the IV lines that made him anxious for Mia and Agami, born 3 1/2 months too soon. A musician and a neurology researcher, Lahav also worried about the din of the neonatal intensive care unit. The soundscape of the womb had been replaced by beeping alarms, pagers, ventilators, and talking. “Every time the door was open, there was so much noise coming in from the room,’’ Lahav said. He persuaded Dr. Steven Ringer, chief of newborn medicine at Brigham and Women’s Hospital, to allow him to play a recording of his wife, Galit, speaking to the infants. When the parents could not be there to snuggle the babies directly on their skin, the recording could be played on a small speaker in their incubators. He hoped it would make the hospital sound more like the womb, in which babies can hear their mother’s muffled voice and heartbeat. At the time, in 2007, Lahav was thinking with his gut, not his head. But he began to realize this was a critical period — a time when the twins’ developing brains were especially malleable, with neurological connections being formed and molded as easily as Play-Doh. He wondered whether the abrupt change in the acoustic environment could be one reason that premature babies are more likely to have developmental problems later, including learning disabilities, cognitive or language deficits, or attention problems. © 2011 NY Times Co.

Keyword: Development of the Brain; Language
Link ID: 15126 - Posted: 03.22.2011

By SINDYA N. BHANOO It is always a challenge to remember a new computer password after an old one has expired, or to memorize a new phone number. That is because the brain is competing to recall old memories and new ones that are associated with the same thing, researchers from Yale and Stanford report in Proceedings of the National Academy of Sciences. Brice Kuhl, a psychologist at Yale, and his colleagues found that when the brain is cluttered with similar events, the difficulty in recalling just one of them is visible through the brain-scanning technology known as functional magnetic resonance imaging. The researchers provided subjects with words that had both face associations and scene associations. When they ran a scan and asked the subjects to recall the association they had most recently seen, blood flowed in parts of the brain that are used to recall faces and scenes. Most people regularly encounter this competition. “I park in a garage every day at work, and I park in a different space every day, depending on availability,” Dr. Kuhl said. “And I very often walk to where I parked the day before. It’s not that I totally forgot where I parked, it’s just that I still remember yesterday’s spot.” © 2011 The New York Times Company

Keyword: Learning & Memory
Link ID: 15125 - Posted: 03.22.2011

By JOHN TIERNEY Suppose that Mark and Bill live in a deterministic universe. Everything that happens this morning — like Mark’s decision to wear a blue shirt, or Bill’s latest attempt to comb over his bald spot — is completely caused by whatever happened before it. If you recreated this universe starting with the Big Bang and let all events proceed exactly the same way until this same morning, then the blue shirt is as inevitable as the comb-over. Now for questions from experimental philosophers: 1) In this deterministic universe, is it possible for a person to be fully morally responsible for his actions? 2) This year, as he has often done in the past, Mark arranges to cheat on his taxes. Is he is fully morally responsible for his actions? 3) Bill falls in love with his secretary, and he decides that the only way to be with her is to murder his wife and three children. Before leaving on a trip, he arranges for them to be killed while he is away. Is Bill fully morally responsible for his actions? To a classic philosopher, these are just three versions of the same question about free will. But to the new breed of philosophers who test people’s responses to concepts like determinism, there are crucial differences, as Shaun Nichols explains in the current issue of Science. © 2011 The New York Times Company

Keyword: Attention
Link ID: 15124 - Posted: 03.22.2011

By RONI CARYN RABIN Women who take codeine, oxycodone and other opioid pain drugs early in pregnancy may be exposing their babies to a higher risk of birth defects, a new study suggests. Though the overall numbers were small, babies whose mothers took opioids were considerably more likely than others to have congenital problems, including a potentially fatal syndrome in which the left part of the heart does not develop completely; spina bifida; and gastroschisis, in which the intestines stick out of the body. The study, from the Centers for Disease Control and Prevention, was one of the largest to examine the effects of opioid use during pregnancy. It appeared last month in The American Journal of Obstetrics & Gynecology. It used data from the National Birth Defects Prevention Study about mothers in 10 states who gave birth from 1997 to 2005. Of 17,449 mothers whose babies had a birth defect, 454, or 2.6 percent, reported treatment with opioid analgesics a month before pregnancy or during the three months after conception. In the comparison group of 6,701 women, the rate of opioid treatment was 2.0 percent. “Opioids and their receptors act as growth regulators during embryologic development, which may explain our findings,” said Cheryl S. Broussard, the paper’s lead author. © 2011 The New York Times Company

Keyword: Drug Abuse; Development of the Brain
Link ID: 15123 - Posted: 03.22.2011

by Sheril Kirshenbaum; Ill 1 Only you: Human lips are different from those of all other animals because they are everted, meaning that they purse outward. 2 But we are not the only species to engage in kissing-like behaviors. Great apes press their lips together to express excitement, affection, or reconciliation. 3 Scientists are not sure why humans kiss, but some think the answer lies in early feeding experiences. Through nursing and (in some cultures) receiving pre-chewed food from a parent's mouth, infants may learn to associate lip pressure with a loving act. 4 Another possibility: Smelling a loved one's cheek has long served as a means of recognition in cultures around the world, from New Zealand to Alaska. Over time, a brush of the lips may have become a traditional accompaniment. 5 And yet kissing is not universal, leading some experts, like anthropologist Vaughn Bryant of Texas A&M, to think it might actually be a learned behavior. 6 The Roman military introduced kissing to many non-kissing cultures (after its conquests were over, presumably); later it was European explorers who carried the torch. © 2011, Kalmbach Publishing Co.

Keyword: Sexual Behavior; Emotions
Link ID: 15122 - Posted: 03.22.2011

By BRYSON VOIRIN I love to sleep. That feeling when you wake up fully rested, crisp and fresh, is nirvana. Sleep is essential part of our daily lives. Stop sleeping and your body starts losing function, mental clarity evaporates, and you eventually die. Sleep seems to be essential for all animals, given that every animal studied has been found to sleep. Insects, fish, birds, and I all participate in this daily phenomenon. But why do we sleep? What purpose does it serve? The truth is, we don’t really know. We know loads about the neuronal pathways that define the various stages of sleep. We also know what happens when we are sleep-deprived (think of staying up all night for a final exam). But the true purpose of this curious state that we enter nightly remains mysterious. Many researchers are working on solving this enigma through various clinical, experimental and observational studies on humans and animals. For years, researchers have recorded sleep in animals ranging from mice to elephants. But these animals have always been captive, caged or otherwise restrained. Our lab at the Max Planck Institute is the only group studying sleep in wild, unrestrained animals. There is enormous variation in the natural world, with some animals sleeping only two hours a day, while others require 20 hours. To properly understand this variation we have to study them in their natural habitat. It’s not that surprising that the behavior of captive animals is significantly different from that of their wild counterparts. Imagine if I studied sleep only in people on airplanes, and used that to infer that this is their “normal” sleeping pattern. We are hardly the first people to suspect there are differences in the sleep patterns of wild and captive animals. We are just the first to have the technology to effectively study it in the wild. © 2011 The New York Times Company

Keyword: Sleep
Link ID: 15121 - Posted: 03.21.2011

Scientists have shown how a single protein may trigger autistic spectrum disorders by stopping effective communication between brain cells. The team from Duke University in North Carolina created autistic mice by mutating the gene which controls production of the protein, Shank3. The animals exhibited social problems, and repetitive behaviour - both classic signs of autism and related conditions. The Nature study raises hopes of the first effective drug treatments. Autism is a disorder which, to varying degrees, affects the ability of children and adults to communicate and interact socially. While hundreds of genes linked to the condition have been found, the precise combination of genetics, biochemistry and other environmental factors which produce autism is still unclear. Each patient has only one or a handful of those mutations, making it difficult to develop drugs to treat the disorder. Shank3 is found in the synapses - the junctions between brain cells (neurons) that allow them to communicate with each other. The researchers created mice which had a mutated form of Shank3, and found that these animals avoided social interactions with other mice. BBC © MMXI

Keyword: Autism
Link ID: 15120 - Posted: 03.21.2011

By James Gallagher Health reporter, BBC News A new way of delivering drugs to the brain has been developed by scientists at the University of Oxford. They used the body's own transporters - exosomes - to deliver drugs in an experiment on mice. The authors say the study, in Nature Biotechnology, could be vital for treating diseases such as Alzheimer's, Parkinson's and Muscular Dystrophy. The Alzheimer's Society said the study was "exciting" and could lead to more effective treatments. Research barrier One of the medical challenges with diseases of the brain is getting any treatment to cross the blood-brain barrier. The barrier exists to protect the brain, preventing bacteria from crossing over from the blood, while letting oxygen through. However, this has also produced problems for medicine, as drugs can also be blocked. In this study the researchers used exosomes to cross that barrier. Exosomes are like the body's own fleet of incredibly small vans, transporting materials between cells. BBC © MMXI

Keyword: Drug Abuse
Link ID: 15119 - Posted: 03.21.2011

CONJURE up an image of a financial risk-taker, and you'll probably picture an aggressive Wall Street trader, testosterone surging as he closes the deal. But new research suggests that people with low levels of the male sex hormone are also likely to take financial risks. Previous studies have linked high levels of testosterone to certain risk-seeking behaviours. To investigate whether financial risk-taking follows a similar pattern, Scott Huettel at Duke University in Durham, North Carolina, measured the testosterone levels of 298 people, who then took part in trials in which they chose between a fixed known reward or a gamble between getting a payout - mostly larger than the fixed reward - or nothing. Overall, the volunteers generally preferred the known return than the gamble, even if they would have been better off, on average, by taking a chance. Surprisingly, the biggest risks were taken by people with very high or very low testosterone, compared with the average levels for their gender (Psychological Science, DOI: 10.1177/0956797611401752). Economists want to predict who is likely to be successful at playing financial markets, says Dario Mastripieri at the University of Chicago. "It's legitimate to ask if biology is going to have an effect." © Copyright Reed Business Information Ltd.

Keyword: Hormones & Behavior; Emotions
Link ID: 15118 - Posted: 03.21.2011

By Steve Connor, Science Editor They range in size from the tiny Madame Berthe's mouse lemur, weighing little more than an ounce, to the 440lb mountain gorilla. And the primate species, of course, incorporates humans, once famously described as the "third chimpanzee" because of the close genetic similarity with the two living species of chimp, the common chimp and the bonobo. Even without the human component, the primates would include some of the most intelligent life forms on the planet and their extraordinary success is largely down to their relatively large brains, binocular vision and ability to grasp and manipulate objects between their four digits and opposable thumb. Now for the first time scientists have drawn a comprehensive family tree of all living species of primates based on a systematic analysis of scores of key genes embedded within their DNA. It shows that Homo sapiens is just one of dozens of primate species that share a common ancestor, probably a small, shrew-like creature that lived during the age of the dinosaurs some 85 million years ago. The complete phylogenetic tree of primates, published in the online journal PLoS Genetics, is based on a comparative analysis of some 54 separate gene regions within the genomes of 186 species of living primates covering the entire family tree, from the smallest lemur to the largest great ape. Scientists believe the study can, for the first time, accurately place Man within the much bigger and more complex tree of relationships that define primates. It should, they insist, provide invaluable insights into early human origins, as well as the diseases we share with our closest relatives. ©independent.co.uk

Keyword: Evolution
Link ID: 15117 - Posted: 03.19.2011

Philip Ball A pianist plays a series of notes, and the woman echoes them on a computerized music system. The woman then goes on to play a simple improvised melody over a looped backing track. It doesn't sound like much of a musical challenge — except that the woman is paralysed after a stroke, and can make only eye, facial and slight head movements. She is making the music purely by thinking. This is a trial of a computer-music system that interacts directly with the user's brain, by picking up the tiny electrical impulses of neurons. The device, developed by composer and computer-music specialist Eduardo Miranda of the University of Plymouth, UK, working with computer scientists at the University of Essex, should eventually help people with severe physical disabilities, caused by brain or spinal-cord injuries, for example, to make music for recreational or therapeutic purposes. The findings are published online in the journal Music and Medicine1. "This is an interesting avenue, and might be very useful for patients," says Rainer Goebel, a neuroscientist at Maastricht University in the Netherlands who works on brain-computer interfacing. Evidence suggests that musical participation can be beneficial for people with neurodegenerative diseases such as dementia and Parkinson's disease. But people who have almost no muscle movement have generally been excluded from such benefits, and can enjoy music only through passive listening. © 2011 Nature Publishing Group,

Keyword: Hearing; Robotics
Link ID: 15116 - Posted: 03.19.2011