You may think you know the back of your hand like, well, the back of your hand. But scientists have found that our brains contain distorted representations of the size and shape of our hands, with a tendency to think of them as shorter and fatter than they really are. The work could have implications for how the brain unconsciously perceives other parts of the body and may help explain the underpinnings of certain eating disorders in which body image becomes distorted. Neuroscientists at University College London asked more than 100 volunteers to place their left hand palm-down on a table. The researchers covered the volunteers' hands with a board and then asked them to indicate where they thought landmarks such as fingertips lay underneath. This data was used to reconstruct the "brain's image" of the hand. The results, published yesterday in the Proceedings of the National Academy of Sciences, showed a consistent overestimation of the width of the hand. Many of the volunteers estimated their hand was about 80% broader than it really was. "It's a dramatic and highly consistent bias," said Matthew Longo of UCL's Institute of Cognitive Neuroscience, who led the work. "It was the same with estimation of finger lengths. When you get to the ring finger, with the largest bias, it's 30%-40% underestimation." The brain uses several ways to work out the location of different parts of the body. This includes feedback from muscles and joints and also some sort of internal model of the size and shape of each part. Behavioral Health Central © Copyright 2010,

Keyword: Anorexia & Bulimia; Pain & Touch
Link ID: 14187 - Posted: 06.24.2010

By DUFF WILSON Ever since Viagra met blockbuster success in 1998, the drug industry has sought a similar pill for women. Now, a German drug giant says it has stumbled upon such a pill and is trying to persuade the Food and Drug Administration that its drug can help restore a depressed female sex drive. The effort has set off a debate over what constitutes a normal range of sexual desire among women, with critics saying the company is trying to turn a low libido into a medical pathology. On Wednesday, an F.D.A. staff report recommended against approving the drug, saying the maker, Boehringer Ingelheim, had not made its case and that the benefits of the daily pill did not outweigh its side effects, which included dizziness, nausea and fatigue. That staff report came ahead of a meeting Friday by an F.D.A. advisory panel of experts who are to vote on whether to recommend that the agency approve the pill, which would be the first drug aimed specifically at a low sex drive in premenopausal women. F.D.A. staff reports carry weight but do not always sway how advisory panels vote, and advisory votes do not always predict what the F.D.A. might finally decide. Some analysts forecast that if the drug does reach the market, it could have annual sales in this country of $2 billion — or about equal to the current combined annual American sales of the men’s drugs Viagra, Levitra and Cialis. Copyright 2010 The New York Times Company

Keyword: Sexual Behavior
Link ID: 14186 - Posted: 06.24.2010

By Piercarlo Valdesolo Take a look at the cup of coffee in front of you. Think of how badly you want it. Think of the warmth it will bring as it slips past your pursed lips and reaches through your body’s core. The inviting astringency that lingers on your tastebuds, and that can only be abated by another sip. Once you have worked yourself into a caffeine-deprived frenzy, reach out your hand and try and grasp your liquid gold. New research conducted by Emily Balcetis and David Dunning and published in a recent issue of the journal Psychological Science suggests that you might not reach far enough. The coffee cup appears closer than it really is. This may sound absurd to those of us who believe we see the natural world as it is. How far away am I from my coffee mug? Why, as far away as it looks! The authors’ argument, however, rests on the idea that the way we see the world can be distorted by the way we feel and think about it. Their research is part of an emerging body of work supporting this idea. For example, researchers have found that hills appear steeper and distances longer when people are fatigued or carrying heavy loads. The difficulty of the task distorts our perception of distance. This will ring true for any post-holiday jogger who might at first be astonished at how long a mile appears with the weight of turkey, stuffing and cheesecake dangling from his sides. But as the pounds drip away, the mile marker doesn’t look quite so distant. Anyone who has been tasked with exceedingly tedious administrative work probably has an intimate understanding of this well. As I grade student exams, the more tedious the work, the less of an impact I seem to be making in that tall stack of papers in front of me. Haven’t I been doing this for two hours already? © 2010 Scientific American,

Keyword: Emotions; Vision
Link ID: 14185 - Posted: 06.24.2010

By Lindsey Konkel Alzheimer's disease and its associated dementia can be a scary prospect for individuals and families faced with it. Between 2.4 million and 4.5 million Americans suffer from this debilitating, incurable disease, according to the National Institutes of Health. That figure is expected to rise as the baby boomers age. Community memory screening events are becoming increasingly popular as individuals and their families seek to detect dementia in its earliest stages—before it destroys patients' memories and thinking skills. But many physicians warn against these screenings, which are often ineffective when it comes to detecting dementia, and can leave test-takers feeling scared and powerless. There are thousands of memory screening tests available, some self-administered online, some given in the community by health care professionals—usually in the form of a questionnaire. The Alzheimer's Foundation of America, the advocacy group that funds National Memory Screening Day, promotes screenings overseen by health care professionals only. "If someone goes online and does a self test, even if there are two pages of explanation of the results, I'm not sure that people understand what they are reading," says Eric Hall, the foundation's president and founder. © 2010 Scientific American,

Keyword: Alzheimers; Learning & Memory
Link ID: 14184 - Posted: 06.24.2010

By Jennifer Viegas A quick phone call to dad, or any other man, is far more revealing than previously thought, since new research has just determined that a human male's voice reveals his upper body strength, fighting ability, overall health, age, and emotional state. Just hearing the sound of a man's voice, no matter what he is saying, communicates all of this information and more, according to the study, published in the latest Proceedings of the Royal Society B. The findings put men on vocal par with red deer, common loons, baboons, croaking gourami fish, owls and other animals whose calls also directly communicate body strength and fighting ability. "Ancestrally, a man's fighting ability would have been much more important to know as archaeological and anthropological evidence indicates that men were much more likely to engage in aggression than women were," Aaron Sell, lead author of the paper, told Discovery News. "For that reason, it's very important to know how formidable a man is," added Sell, a researcher in the Center for Evolutionary Psychology at the University of California, Santa Barbara. Sell and his colleagues took body and strength measurements from men and women belonging to four distinct populations: the Tsimane of Bolivia, Andean herder-horticulturalists, and U.S. and Romanian college students. © 2010 Discovery Communications, LLC.

Keyword: Sexual Behavior; Evolution
Link ID: 14183 - Posted: 06.17.2010

Neuroscientists usually explain color illusions in mechanistic terms: They arise because of the way cells in the retina and the brain respond to certain wavelengths of light. Those explanations miss the larger point, says Beau Lotto, a brain research at University College London. We misperceive colors and shapes because our visual sense has been molded by evolutionary history.

Keyword: Vision
Link ID: 14182 - Posted: 06.17.2010

by Carl Zimmer This month’s column is a tale of two rats. One rat got lots of attention from its mother when it was young; she licked its fur many times a day. The other rat had a different experience. Its mother hardly licked its fur at all. The two rats grew up and turned out to be very different. The neglected rat was easily startled by noises. It was reluctant to explore new places. When it experienced stress, it churned out lots of hormones. Meanwhile, the rat that had gotten more attention from its mother was not so easily startled, was more curious, and did not suffer surges of stress hormones. The same basic tale has repeated itself hundreds of times in a number of labs. The experiences rats had when they were young altered their behavior as adults. We all intuit that this holds true for people, too, if you replace fur-licking with school, television, family troubles, and all the other experiences that children have. But there’s a major puzzle lurking underneath this seemingly obvious fact of life. Our brains develop according to a recipe encoded in our genes. Each of our brain cells contains the same set of genes we were born with and uses those genes to build proteins and other molecules throughout its life. The sequence of DNA in those genes is pretty much fixed. For experiences to produce long-term changes in how we behave, they must be somehow able to reach into our brains and alter how those genes work. Neuroscientists are now mapping that mechanism. Our experiences don’t actually rewrite the genes in our brains, it seems, but they can do something almost as powerful. Glued to our DNA are thousands of molecules that shut some genes off and allow other genes to be active. Our experiences can physically rearrange the pattern of those switches and, in the process, change the way our brain cells work. This research has a truly exciting implication: It may be possible to rearrange that pattern ourselves and thereby relieve people of psychiatric disorders like severe anxiety and depression. In fact, scientists are already easing those symptoms in mice.

Keyword: Genes & Behavior; Depression
Link ID: 14181 - Posted: 06.24.2010

by Jessica Hamzelou Sea snail venom could become the gold standard for the relief of nerve-related pain following the development of a pill that is 100 times as potent as leading treatments. Current treatments for neuropathic pain include morphine, which is highly addictive, and gabapentin, which both act on nerve receptors. Sea snail venom had been suggested as a good alternative because it consists of a cocktail of peptides, known as conotoxins. These act to immobilise prey by blocking nerve-cell conduction, but in mammals the peptides are an effective analgesic. The only conotoxin-derived drug approved for human use is ziconotide. Unfortunately, the drug is susceptible to breakdown by enzymes in the saliva and gut, so it is administered by a pump surgically inserted into the abdominal wall, making it an invasive and expensive treatment. To solve this problem, David Craik and his team at the University of Queensland in Australia have developed the first "orally active" conotoxin drug. They started with a synthetic version of conotoxin. Since the enzymes that break down the drug usually act at the ends of the conotoxin molecule, the team used a chain of amino acids to join up these ends to form a circular structure. They found this version to be resistant to enzymes in the body. © Copyright Reed Business Information Ltd.

Keyword: Pain & Touch
Link ID: 14180 - Posted: 06.24.2010

Charles Q. Choi Networks of brain cells in a petri dish can be trained to keep time like hourglasses, a new study says. The discovery may help scientists reveal how our brains track time, an ability fundamental to how humans interact with each other and the world. It's also key to how we recognize speech patterns and song rhythms.cn "One issue that's been long debated regarding timing is whether there's a central clock in the brain or whether timing is a general ability in many different circuits of the brain," said study leader Dean Buonomano, a neuroscientist at University of California, Los Angeles. Buonomano and colleagues kept networks of rat brain cells alive in petri dishes and stimulated them with two electrical pulses separated by intervals ranging from a twentieth of a second to a half-second in length. After the cell networks received two hours of "training," a single electrical pulse was given to them to see how the cells would react. In networks trained with short intervals, the communication between cells lasted for only a short while—say, 50 to 100 milliseconds in networks trained on 50-millisecond intervals. However, in networks trained with long intervals, network activity lasted for much longer, according to the study, published June 13 in Nature Neuroscience. When networks trained on half-second intervals were probed, the networks essentially talked to each other for 500 to 600 milliseconds. © 1996-2010 National Geographic Society

Keyword: Biological Rhythms
Link ID: 14179 - Posted: 06.24.2010

Virginia Hughes How long does a fruit fly sleep? That depends on its genetic make-up, according to research presented this weekend at a meeting of the Genetics Society of America in Boston, Massachusetts. Researchers identified nearly 1,000 genes in which certain single-letter changes in DNA, called SNPs (for single nucleotide polymorphisms), are associated with the length of sleep. This preliminary study is the first to come out of the Drosophila Genetic Reference Panel project, a catalogue of variations across the complete genomes of 192 inbred lines of the fruit fly Drosophila melanogaster. So far, the researchers have deposited raw sequence data from 152 lines in a freely available database, spurring roughly 50 other groups to begin genome-wide association (GWA) studies, which compare the SNPs of flies that show various complex behaviours. "Once all of the data are out, there will be an army of people who will immediately go after it," says Charles Langley, a population geneticist at the University of California, Davis, who was not involved in the latest study. Variant flood In the past few years, the field of human genetics has seen a deluge of GWA studies that have identified thousands of genetic variants associated with complex disease. One problem with this approach, however, is that there is no way to know whether the identified SNPs are causal for a disease. © 2010 Nature Publishing Group,

Keyword: Sleep; Genes & Behavior
Link ID: 14178 - Posted: 06.24.2010

By Julie Steenhuysen CHICAGO - A study of brain scans has confirmed the role of several genes linked with Alzheimer's disease, and turned up two others that are worth exploring, U.S. researchers said Monday. A team at Massachusetts General Hospital in Boston used magnetic resonance imaging or MRI scans to study changes in brain structures — such as the size of the hippocampus and amygdala — in 700 healthy volunteers and Alzheimer's patients. They used computer programs to sort through the genetic sequences of the 700 volunteers to see which gene mutations are most linked with these changes. Story continues below ↓advertisement | your ad here The study turned up a known offender — the APOE4 gene — as the most strongly linked with the disease, but it also confirmed three other genes — CLU, CRI, PICALM — that have been more recently linked with Alzheimer's. And they fingered two others — BIN1 and CNTN5 — which have been suspected, but not strongly linked with Alzheimer's. While the findings are preliminary, "they may help prioritize targets for future genetic studies," Drs. Alessandro Biffi and Christopher Anderson of Massachusetts General and the Broad Institute wrote in the Archives of Neurology. Copyright 2010 Reuters.

Keyword: Alzheimers; Brain imaging
Link ID: 14177 - Posted: 06.24.2010

By NATALIE ANGIER Not long ago, Julia Fischer of the German Primate Center in Göttingen was amused to witness two of her distinguished male colleagues preening about a topic very different from the standard academic peacock points — papers published, grants secured, competitors made to look foolish. “One of them said proudly, ‘I have three children,’ ” Dr. Fischer recalled. “The other one replied, ‘Well, I have four children.’ “Some men might talk about their Porsches,” she added. “These men were boasting about their number of children.” And while Dr. Fischer is reluctant to draw facile comparisons between humans and other primates, she couldn’t help thinking of her male Barbary macaques, for whom no display carries higher status, or is more likely to impress the other guys, than to strut around the neighborhood with an infant monkey in tow. Reporting in the current issue of the journal Animal Behaviour, Dr. Fischer and her co-workers describe how male Barbary macaques use infants as “costly social tools” for the express purpose of bonding with other males and strengthening their social clout. Want to befriend the local potentate? Bring a baby. Need to reinforce an existing male-male alliance, or repair a frayed one? Don’t forget the baby. It doesn’t matter if the infant is yours or not. Just so long as it has the downy black fur and wrinkly pinkish face that adult male macaques find impossible to resist. “They will hold up the infant like a holy thing, nuzzling it, chattering their teeth,” Dr. Fischer said. “It can be a bit bewildering to see.” Copyright 2010 The New York Times Company

Keyword: Sexual Behavior
Link ID: 14176 - Posted: 06.24.2010

By Katherine Harmon To function well in the world, people need a good sense of where their body is in space and how it's postured. This "position sense" helps us coordinate high-fives, boot a soccer ball or pick up the remote. But that doesn't seem to mean that our brains have an accurate sense of our body's precise proportions. A new study found that people tend to have rather inaccurate mental models of their own hands. When asked to estimate where the fingertips and knuckles of their hidden hands were, study volunteers were way off. But they were all incorrect in the same directions, guessing that their hands were both shorter and wider than they actually were. The findings come from a study led by Matthew Longo of the Institute of Cognitive Neuroscience at University College London and were published online June 14 in Proceedings of the National Academy of Sciences. "Our results show dramatic distortions of hand shape, which were highly consistent across participants," Longo said in a prepared statement. He and his coauthor, Patrick Haggard, had subjects place their left hand on a platform (using different orientations in different groups), which was then covered with a board to obscure the hand. The subjects were asked to use their free right hand point with a baton to the location of each knuckle and fingertip of their left hand. The process was filmed and compared to before and after pictures of the hand. © 2010 Scientific American,

Keyword: Pain & Touch
Link ID: 14175 - Posted: 06.24.2010

Analysis by Teresa Shipley It sounds like an experiment kids might conduct. Pairs of female jumping spiders were matched off in a mini, gladiator-like arena, while researchers recorded fight tactics in an effort to find a pattern. What did they find? The females fight dirty. While the males "push each other back and forth like sumo wrestlers," lead author Damian Elias of the University of California at Berkeley said in a press release, the females displayed less civil tactics. The research is published online in the journal Behavioral Ecology. "Males have a more gentlemanly form of combat, whereas in females it's an all-out fight," said Elias. "At the drop of a hat they start bashing and biting each other." Another difference was that the female fights were often duels to the death, whereas males tended to resolve things through elaborate dance displays rather than fighting. The researchers were baffled about why this happened. "Nothing we could measure predicted which one would come out on top," Elias said. "That was really unexpected." Finally, they hit upon a hypothesis. What if the females had a reason to fight other than territory? They found that the females who were closer to "molting," a process that happens right before eggs are laid, were more likely to win a fight. The researchers think this may be because molting females are much more vulnerable to predation, and so much more motivated to survive. © 2010 Discovery Communications, LLC.

Keyword: Aggression; Evolution
Link ID: 14174 - Posted: 06.24.2010

By Victoria Gill Have you ever failed to notice a friend's radical new haircut? Or missed a road sign showing a change in the speed limit? This failure to notice what should be very apparent is something we unconsciously experience every day as our brains filter the barrage of visual information which we are flooded with. And apparently it has a name; it is called change blindness. Scientists at Queen Mary, University of London, have invented a unique spot-the-difference-style computer game in order to study it. Milan Verma, a scientist at Queen Mary, explains: "It's the phenomenon where seemingly striking or obvious changes are not noticed." He and his colleagues are asking volunteers to play the game - which involves looking at a screen as it flashes between two images of the same scene. "It flicks between a pre-change version and a post-change version of the scene," Dr Verma explains. "The volunteers simply have to press the button and tell us exactly when they spot the change." Trying out the game at Dr Verma's office, my initial reaction was self-satisfaction; I spotted the difference in the first scene - a picture of a butterfly with orange stripes on its wings - almost immediately. BBC © MMX

Keyword: Vision; Attention
Link ID: 14173 - Posted: 06.24.2010

Janet Fang To follow the scent trail left by their prey across the ocean, sharks swim in the direction of the nostril that sniffed the odour first, scientists have found. Their research challenges the classic notion that sharks orient themselves based on the differences between odour concentration received at each nostril. Shark prey — whether living, injured or dead — leaves behind swirling odour plumes that break apart with distance. The latest work, published today in Current Biology1, suggests that when a shark moves into a patch of odour, the smell hits one nostril before the other — and that tells the shark to turn either left or right. By moving from side to side from one patch to another, the animal maintains contact with the odour plume as it tracks its prey, says Jayne Gardiner at the University of South Florida in Tampa, co-author of the study. Ocean odours mix chaotically, so for sharks to steer using odour concentration, they would need to compare the average concentration at the two nostrils over a period of several minutes to determine the prey's direction. They would then have to reposition themselves and start again — a slow process. But by using timing cues, says Gardiner, sharks receive directionality in under a second. The study centred around lab studies of eight smooth dogfish (Mustelus canis), a small grey-brown shark. To recreate prey odour, Gardiner marinated squid — what she calls "junk food for dogfish" — in 50 litres of seawater. She fitted the sharks with headgear consisting of two tubes delivering this squid marinade to one nostril and then the other. She found that for delays between 0.1 and 0.5 seconds, the sharks turned toward the side receiving the first stimulus. If there was no time lag or if the lag was a second or longer, the sharks were equally likely to turn in either direction. © 2010 Nature Publishing Group,

Keyword: Chemical Senses (Smell & Taste)
Link ID: 14172 - Posted: 06.24.2010

Scientists have discovered that a gene linked to Alzheimer’s disease may play a beneficial role in cell survival by enabling neurons to clear away toxic proteins. A study funded by the National Institute on Aging (NIA), part of the National Institutes of Health, shows the presenilin 1 (PS1) gene is essential to the function of lysosomes, the cell component that digests and recycles unwanted proteins. However, mutations in the PS1 gene — a known risk factor for a rare, early onset form of Alzheimer’s disease — disrupt this crucial process. Ralph Nixon, M.D., Ph.D., of the Nathan Kline Institute, Orangeburg, N.Y., and New York University Langone Medical Center, directed the study involving researchers from the United States, Europe, Japan and Canada. Also supported in part by the Alzheimer’s Association, the study appears in the June 10, 2010, online issue of Cell. Researchers have theorized for more than a decade that PS1 mutations linked to early-onset Alzheimer's, a rare form of the disease that usually affects people between ages 30 and 60, may trigger abnormally high levels of beta-amyloid protein to clump together in the brain. Amyloid deposits and tau protein tangles are hallmarks of both early-onset and the sporadic, more common form of the disease found in people aged 60 and older. These new findings, however, suggest PS1 mutations may play a more general role in the development of early-onset Alzheimer's.

Keyword: Alzheimers; Apoptosis
Link ID: 14171 - Posted: 06.24.2010

by Adam Hadhazy Nerve cells in our sweat glands and blood vessels may constitute an important, previously unrecognized source of sensory info. You are more sensitive than you realize, neuroscientist Frank Rice of Albany Medical College has discovered. His study of patients whose skin lacks normal nerve fibers has revealed a previously unknown source of perception that contributes to the familiar ability to feel texture, temperature, pressure, and pain: the nerve endings surrounding blood vessels and sweat glands in human skin. Rice, neurologist David Bowsher of the University of Liverpool, and their colleagues were studying two patients who were unable to feel pain, yet somehow retained a rudimentary ability to distinguish hot from cold and rough from smooth. On examining skin samples and other biopsies, the researchers found that all of the usual nerve endings associated with skin sensation were missing. The only possible sources of feeling were the nerves of the blood vessels and glands. Scientists knew that such nerves existed but thought they simply regulated blood flow and perspiration. The evidence from the patients examined by Rice and Bowsher suggests that the nerve cells also act as an additional sensory system. “It is very likely that these nerve endings contribute to conscious perception in all of us,” Rice says. If he is correct, problems with this previously unknown system could contribute to poorly understood pain conditions, such as migraines and fibromyalgia. Rice and a group of collaborators are gearing up to investigate this potential link by searching for malformations of the blood-vessel nerves that could affect their function.

Keyword: Pain & Touch
Link ID: 14170 - Posted: 06.24.2010

by John Travis More than 3 years after initially passing peer review and being accepted, a controversial paper addressing how to diagnose psychopathy and whether past criminal behavior is central to the condition has been published in the June issue of Psychological Assessment. The paper has privately circulated among forensic psychologists since 2007, but some of the explanation behind its publishing delay became evident last month when a commentary in International Journal of Forensic Mental Health made it a matter of public knowledge that forensic psychologist Robert Hare of the University of British Columbia,Vancouver, had threatened to file a defamation lawsuit against the authors and the journal's publisher. The Psychological Assessment article, by Jennifer Skeem, a forensic psychologist at the University of California, Irvine, and psychologist David Cooke of Glasgow Caledonian University, is critical of a widely used diagnostic tool developed by Hare called Psychopathy Checklist-Revised (PCL-R) and what the article labels as Hare's construct of psychopathy. Hare, however, saw a copy of the paper prepublication and took exception to Skeem and Cooke's portrayal of PCL-R, his work, and his writings. On 8 November 2007, lawyers representing Hare sent an e-mail to the American Psychological Association (APA), Skeem, and Cooke threatening a defamation lawsuit. "In 40 years, I've engaged in some heated academic debates, but in the journals. This time was different because it had little to do with scientific/academic discourse and everything with taking unwarranted shots at me as a straw man," Hare says. © 2010 American Association for the Advancement of Science.

Keyword: Aggression
Link ID: 14169 - Posted: 06.24.2010

By THE NEW YORK TIMES Dozens of readers had questions about Tourette’s syndrome, the odd and poorly understand disorder that causes uncontrollable tics and vocalizations, after the disorder was profiled in a recent Patient Voices series. Here, Dr. Robert A. King and Dr. James F. Leckman of Yale School of Medicine respond to readers wondering whether Tourette’s is inherited and how common the disorder is. Is Tourette’s Inherited? My daughter is engaged to someone with Tourette’s. I worry about their children inheriting Tourette’s. What is the likelihood of that occurring? Anonymous, San Francisco Dr. King and Dr. Leckman respond: Tourette’s likely has genetic determinants, but they may vary from family to family. When a parent has Tourette’s, sons have a higher risk of inheriting the condition than daughters. On average, about 20 percent of male offspring will have Tourette’s, compared to only about 5 percent of female offspring. The rates for a chronic motor tic disorder are a bit higher: 30 percent of the sons and about 9 percent of the daughters will have such a condition. In contrast, the rates are reversed for obsessive-compulsive disorder, or O.C.D., which sometimes accompanies Tourette’s, with 7 percent of sons and 15 percent of daughters developing symptoms of O.C.D. These are all approximate figures. Copyright 2010 The New York Times Company

Keyword: Tourettes
Link ID: 14168 - Posted: 06.24.2010