By Melinda Wenner Moyer Thirty years ago, America declared war against fat. The inaugural edition of Dietary Guidelines for Americans, published in 1980 and subsequently updated every five years, advised people to steer clear of "too much fat, saturated fat, and cholesterol," because of purported ties between fat intake and heart disease. The message has remained essentially the same ever since, with current guidelines recommending that Americans consume less than 10 percent of their daily calories from saturated fat. But heart disease continues to devastate the country, and, as you may have noticed, we certainly haven't gotten any thinner. Ultimately, that's because fat should never have been our enemy. The big question is whether the 2010 Dietary Guidelines, due out at the end of the year, will finally announce retreat. The foundation for the "fat is bad" mantra comes from the following logic: Since saturated fat is known to increase blood levels of "bad" LDL cholesterol, and people with high LDL cholesterol are more likely to develop heart disease, saturated fat must increase heart disease risk. If A equals B and B equals C, then A must equal C. Well, no. With this extrapolation, scientists and policymakers made a grave miscalculation: They assumed that all LDL cholesterol is the same and that all of it is bad. A spate of recent research is now overturning this fallacy and raising major questions about the wisdom of avoiding fat, especially considering that the food Americans have been replacing fat with—processed carbohydrates—could be far worse for heart health. © Copyright 2010 Washington Post.Newsweek Interactive Co. LLC

Keyword: Obesity
Link ID: 13953 - Posted: 06.24.2010

Mind reading may no longer be the domain of psychics and fortune tellers - now some computers can do it, too. Software that uses brain scans to determine what items people are thinking about was among the technological innovations showcased Wednesday by Intel, which drew back the curtain on a number of projects that are still under development. The software analyzes functional MRI scans to determine what parts of a person's brain is being activated as he or she thinks. In tests, it guessed with 90 per cent accuracy which of two words a person was thinking about, said Intel Labs researcher Dean Pomerleau. Eventually, the technology could help the severely physically disabled to communicate. And Pomerleau sees it as an early step toward one day being able to control technology with our minds. "The vision is being able to interface to information, to your devices and to other people without having an intermediary device," he said. For now, the project's accomplishments are far more modest - it can only be used with prohibitively expensive and bulky fMRI equipment and hasn't yet been adapted to analyze abstract thoughts. The system works best when a person is first scanned while thinking of dozens of different concrete nouns - words like "bear" or "hammer." When test subjects are then asked to pick one of two new terms and think about it, the software uses the earlier results as a baseline to determine what the person is thinking. ©independent.co.uk

Keyword: Brain imaging
Link ID: 13952 - Posted: 06.24.2010

by Ewen Callaway DEEP brain stimulation has long been psychiatry's black magic: stick electrodes into a region linked to mental illness, deliver rapid pulses of weak current, and voila! Crippling symptoms of depression, obsessive compulsive disorder and even substance abuse are eased. Now brain imaging of people undergoing deep brain stimulation (DBS) to treat depression is revealing the mechanism behind these effects - and who it will and won't work on. The crucial discovery is that DBS seems to tune an array of brain regions, not just the area around the electrode. This once fringe treatment is now creating a new view of mental illness as a condition affecting an interconnected network rather than arising from chemical imbalances in specific regions. "The brain works on a circuit board," says Helen Mayberg of Emory University in Atlanta, Georgia, whose team is lifting the veil on DBS. DBS involves continually delivering high-frequency pulses of weak current to a particular region via stimulators that are surgically inserted into the brain. Although invasive, it works so well for Parkinson's disease and other movement disorders that it is now mainstream, with tens of thousands of patients implanted. In the last decade, researchers have tested DBS on a variety of other conditions. It has proved effective at reducing some symptoms of bipolar disorder and Tourette's syndrome (see table). It was recently approved by the US Food and Drug Administration to treat obsessive compulsive disorder. © Copyright Reed Business Information Ltd

Keyword: Parkinsons
Link ID: 13951 - Posted: 06.24.2010

by Linda Geddes Waist circumference: 77.5 centimetres (30.5 inches) Five months to go until I give birth to our first child, and the trials of life and work are starting to get to me. If that weren't enough, the onslaught of news stories about stress during pregnancy is enough to raise my blood pressure still further. Last week it was stress during pregnancy gives your child asthma. Then there were the studies hinting that stress inhibits growth in the emotional areas of babies' brains, raises the risk of stillbirth and makes your child more likely to develop schizophrenia. What's a pregnant woman to make of all this? One of the problems with these studies is that repeatedly stressing animals in a lab environment is hardly the same as juggling work deadlines, gym classes and social arrangements. Neither is London, my home, a war zone – as was the location in the schizophrenia study. What we need are studies that measure stress more directly, and fortunately I've found two that do just that. Unlike many previous studies, they rely on direct measurements of the fetus or its immediate environment, the amniotic fluid. And they are throwing up some surprising results, including that moderate levels of stress might be good for fetal development. © Copyright Reed Business Information Ltd

Keyword: Stress; Development of the Brain
Link ID: 13950 - Posted: 06.24.2010

Janelle Weaver Pigeons wearing miniature backpacks containing tracking devices have revealed that the birds rapidly shift direction during flight in response to cues from the leading members of their group. "It is the first study demonstrating hierarchical decision-making in a group of free-flying birds," says Tamás Vicsek, a biophysicist at Eötvös Loránd University in Budapest who led the study, which is published today in Nature1. The discovery became possible only recently with the introduction of Global Positioning System (GPS) devices that can collect data at a high rate: five times per second. Vicsek's team strapped lightweight GPS devices to individual pigeons and tracked flocks of up to 10 birds during free flights lasting around 12 minutes and 15-kilometre homing flights. In total, the GPS logged 32 hours of data and captured 15 group flights. The researchers couldn't pinpoint individuals' exact positions within a flock, but were able to accurately compare birds' directions of motion. Within flocks, the authors looked first at the behaviour of pairs of birds. For each possible pairing, the team identified a leader — the bird that changed direction first — and a follower, which copied the leader's motion. Followers reacted very quickly, within a fraction of a second. Next, the scientists constructed a network of relationships among birds in the group during each flight. They uncovered a robust pecking order: birds higher up the ranks had more influence over the group's movements, and each individual's level of influence was consistent across specific free and homing flights. © 2010 Nature Publishing Group,

Keyword: Aggression; Animal Migration
Link ID: 13949 - Posted: 06.24.2010

By Katherine Harmon The spy shot the cop with the revolver. This sentence, a favorite of linguists, appears to be simple enough. It's grammatically correct, has a subject and a predicate and can even be easily understood by young children. Or can it? Who had the revolver: the spy or the cop? Like optical illusions, language can play tricks on the brain, explained New York University psychologist Gary Marcus at an April 6 lecture at the American Museum of Natural History in New York. These simple syntactic ambiguities, he argued, throw a wrench into prevalent theories that the human brain is well evolved—or even optimally evolved—for language. As evidence for our species' general optimality, many people point to the complex human visual system, which has yet to be matched by technological developments. So if our brain's handling of vision is so well tuned, shouldn't our language centers be as well? No way, according to Marcus. Visual abilities have been developing in animal predecessors for hundreds of millions of years. Language, on the other hand, has had only a few hundred thousand years to eke out a place in our primate brain, he noted. What our species has come up with is a "kluge," Marcus said, a term he borrows from engineering that means a solution that is "clumsy and inelegant, but it gets the job done." (His 2008 book, Kluge: The Haphazard Construction of the Human Mind, explores the language subject and other human mental inefficiencies.) © 2010 Scientific American

Keyword: Language; Evolution
Link ID: 13948 - Posted: 06.24.2010

By RANDI HUTTER EPSTEIN Shirley Koecheler, 54, has been a sleepwalker for as long as she can remember. But it wasn’t until she got married that she started eating in her sleep, too. She’d wander into the kitchen — eyes open but asleep — and binge on junk food. Like so many of those with sleep-related eating disorder, Ms. Koecheler, a businesswoman and farmer from Maple Plains, Minn., does not remember anything about her nighttime journeys. When she wakes up the next morning to a crumb-filled bed, uncomfortably full, she knows that she must have spent the night feasting. “I’ve gained seven pounds in the past two months,” Ms. Koecheler said. “I bought the Easter candy for the kids and had my husband hide it, but I must have found it during the night. I found the wrappers in the wastebasket from the solid chocolate bunnies.” Sleep eaters “make a beeline for the kitchen” and tend to binge on sugary, high-calorie snacks, sometimes five times a night, said Dr. John W. Winkelman, medical director of the Sleep Health Center of Brigham and Women’s Hospital in Brighton, Mass. Some go for bizarre food combinations like peanut butter and pasta, and even the occasional nail polish or paper. Consequences of nighttime eating can include injuries like black eyes from walking into a wall or hand cuts from a prep knife, or dental problems from gnawing on frozen food. On a deeper level, many sleep eaters feel depressed, frustrated and ashamed. Upwards of 10 percent of adults suffer from some sort of parasomnia, or sleep disorder, like sleepwalking or night terrors. Some have driven cars or performed inappropriate sexual acts — all while in a sleep-induced fog. About 1 percent, mostly women, raid the refrigerator. Copyright 2010 The New York Times Company

Keyword: Sleep
Link ID: 13947 - Posted: 06.24.2010

By MARIA CHENG LONDON - Lithium doesn't help patients with ALS, or Lou Gehrig's disease, contrary to previous study results, new research says. Results from a small study published two years ago suggested the drug, often used for depression, could slow the fatal neurological disorder. Many ALS sufferers and their families rushed to try it, spearheading a patient-led effort to test lithium without doctors. In the first trial to scientifically assess whether lithium works for Lou Gehrig's disease, doctors found it had no effect — and stopped the study early because it seemed futile. The results were published online Tuesday in the medical journal, Lancet Neurology. American and Canadian doctors enrolled 84 patients with Lou Gehrig's disease into their study across both countries. About half the patients got lithium and riluzole, the standard drug used for the disease. The other half got riluzole plus placebo pills. After nearly six months, researchers didn't see any difference: 22 of the 40 patients in the lithium group had gotten worse versus 20 of 44 patients in the placebo group. Patients on lithium were more likely to have fallen and suffer back pain. The study was funded by the U.S. National Institute of Neurological Disorders and Stroke, the ALS Association and the ALS Society of Canada. Copyright 2010 The Associated Press.

Keyword: ALS-Lou Gehrig's Disease
Link ID: 13946 - Posted: 06.24.2010

By BENEDICT CAREY MEDFORD, Mass. — The woman was afraid and alone, a fragile soul in a wheelchair who had managed to stuff a few possessions into a plastic garbage bag before being evacuated. Like many of the Hurricane Katrina refugees who straggled into Baton Rouge, La., in the summer of 2005, she needed more than food and shelter. She needed company, sympathy — someone, anyone, to see and feel her loss — and searched the face of her assigned social worker in vain. But the social worker, barely out of college, seemed somehow emotionally removed. Something was missing. “I could see the breakdown in the emotional connection between us, could see it happening and there was nothing I could do,” said Kathleen Bogart, 28, the social worker who is now a psychology researcher at Tufts University here. Ms. Bogart has Moebius syndrome, a rare congenital condition named for a 19th-century neurologist that causes facial paralysis. When the people she helped made a sad expression, she continued, “I wasn’t able to return it. I tried to do so with words and tone of voice, but it was no use. Stripped of the facial expression, the emotion just dies there, unshared. It just dies.” Researchers have long known that facial expressions are crucial to social interaction and have categorized them in great detail. They know which expressions are universal; they can distinguish slight differences in expression, for example between a polite smile and a genuine one. Copyright 2010 The New York Times Company

Keyword: Emotions
Link ID: 13945 - Posted: 06.24.2010

by Emma Young "THERE is no great genius without a tincture of madness." So wrote the Roman philosopher Seneca, nearly 2000 years ago. Today it is routine for creative geniuses from history to get retrospective diagnoses of mental illness - some more believable than others. Schizophrenia and other forms of psychosis are the most common illnesses cited, with Newton and Einstein among the most famous subjects. Vincent van Gogh and Virginia Woolf have been linked with bipolar disorder. Few would argue that full-blown psychosis is conducive to creative accomplishment, but perhaps a little bit helps. Psychiatrists view mental health as a spectrum, with serious illness at one end and "normality" at the other. Perhaps those in the middle have enhanced creative tendencies. Some evidence comes from considering the relative dominance of the right and left hemispheres of the brain. There is much dubious pop psychology written about "right-brain people" and "left-brain people", but it is accepted that the left side is mainly involved in language and logical analysis, while the right side is more involved in creative thought. Various techniques for studying dominance do seem to show that people with schizophrenia have more right-brain activity. There is also genetic evidence relating to a protein called neuregulin 1, which is involved in brain development in the womb. Jeremy Hall of the University of Edinburgh, UK, found that a mutation in the gene that codes for the protein is linked to a higher risk of schizophrenia. And last year, Szabolcs Kéri at Semmelweis University in Hungary found that people with two copies of the mutation scored higher on a creativity test than people with one copy, who in turn scored higher than people with no copies (Psychological Science, vol 20, p 1070). © Copyright Reed Business Information Ltd.

Keyword: Schizophrenia; Depression
Link ID: 13944 - Posted: 06.24.2010

By Scott O. Lilienfeld and Hal Arkowitz The notion that men have shorter fuses than women has acquired the status of a psychological shibboleth. More than 30 years ago Stanford University psychologists Eleanor Maccoby and Carol Jacklin concluded in an influential book that sex differences were minimal in most psychological traits but considerable when it comes to aggression. This opinion has endured ever since. Were Maccoby and Jacklin right? Recent research bears out the broad brushstrokes of their claim but reveals that women can be equally, if less dangerously, belligerent. In 1995 the late psychologist David Lykken of the University of Minnesota wrote that if we could magically place all boys and men between the ages of 12 and 28 in a cryogenic freeze, we would slash the rate of violent crime by two thirds. The data bear out Lykken’s thought experiment. In the U.S., the rate of violent crime for girls and women aged 10 and older is one in 56; the corresponding figure among their male counterparts is one in nine. Men commit close to 90 percent of the murders in the U.S. and more murders than women in all the countries researchers have examined, according to a 1999 report by psychologist Anne Campbell of Durham University in England. Indeed, investigators have consistently found that short of criminal activity, men exhibit more frequent and more extreme levels of physical aggression with one exception: in domestic disputes, as we will see, the tables are often turned. In a 2004 mathematical synthesis of 196 studies (known as a meta-analysis), psychologist John Archer of the University of Central Lancashire in England found that men are more physically aggressive (by various measures) than women across all ages, with the difference peaking between the ages of 20 and 30. © 2010 Scientific American

Keyword: Aggression; Sexual Behavior
Link ID: 13943 - Posted: 06.24.2010

By Michael Shermer In the 1922 poem The Waste Land, T. S. Eliot writes, cryptically: Who is the third who always walks beside you?/When I count, there are only you and I together /But when I look ahead up the white road/There is always another one walking beside you. In his footnotes to this verse, Eliot explained that the lines “were stimulated by the account of one of the Antarctic expeditions [Ernest Shackleton’s] ... that the party of explorers, at the extremity of their strength, had the constant delusion that there was one more member than could actually be counted.” Third man, angel, alien or deity—all are sensed presences, so I call this the sensed-presence effect. In his gripping book, The Third Man Factor (Penguin, 2009), John Geiger documents the effect in mountain climbers, solo sailors and ultraendurance athletes. He lists conditions associated with it: monotony, darkness, barren landscapes, isolation, cold, injury, dehydration, hunger, fatigue and fear. I would add sleep deprivation; I have repeatedly experienced its effects and witnessed it in others during the 3,000-mile nonstop transcontinental bicycle Race Across America. Four-time winner Jure Robic, a Slovenian soldier, recounted to the New York Times that during one race he engaged in combat a gaggle of mailboxes he was convinced were enemy troops; another year he found himself being chased by a “howling band” of black-bearded horsemen: “Mujahedeen, shooting at me. So I ride faster.” © 2010 Scientific American

Keyword: Emotions
Link ID: 13942 - Posted: 06.24.2010

By NATALIE ANGIER I recently tried taking a couple of online personality tests, and I must say I was disappointed by the exercise. I was asked bland amorphisms like whether I was “someone who tends to find fault” with people (duh), is generally “friendly and agreeable” (see previous response), and always “does a thorough job” (can I just skip this question?). Nowhere were there any real challenges like the following: Let’s say you are very hungry, and you go over to your favorite food dish. Inside you see, in addition to the standard blend of peanuts and insect parts, a bright pink plastic frog. How long before you work up the nerve to eat your dinner anyway? Or: You have just been ushered into a room that is in every way familiar, except that somebody has put a scrap of old, brown carpet in the middle of the floor. Do you keep your distance from the novelty item, or do you rush over and start pecking at it? These and other vividly tangible gems are taken from the burgeoning field of animal personality research, the effort to understand why individual members of the same species can be so mulishly themselves, and so unlike one another on a wide variety of behavioral measures. Scientists studying animals from virtually every niche of the bestial kingdom have found evidence of distinctive personalities — bundled sets of behaviors, quirks, preferences and pet peeves that remain stable over time and across settings. They have found stylistic diversity in chimpanzees, monkeys, barnacle geese, farm minks, blue tits and great tits, bighorn sheep, dumpling squid, pumpkinseed sunfish, zebra finches, spotted hyenas, even spiders and water striders, to name but a few. They have identified hotheads and tiptoers, schmoozers and loners, divas, dullards and fearless explorers, and they have learned that animals, like us, often cling to the same personality for the bulk of their lives. The daredevil chicken of today is the one out crossing the road tomorrow. Copyright 2010 The New York Times Company

Keyword: Emotions; Evolution
Link ID: 13941 - Posted: 06.24.2010

By Lisa Grossman The part of the brain that’s used to decode a sentence depends on the grammatical structure of the language it’s communicated in, a new study suggests. Brain images showed that subtly different neural regions were activated when speakers of American Sign Language saw sentences that used two different kinds of grammar. The study, published online this week in Proceedings of the National Academy of Sciences, suggests neural structures that evolved for other cognitive tasks, like memory and analysis, may help humans flexibly use a variety of languages. “We’re using and adapting the machinery we already have in our brains,” says study coauthor Aaron Newman of Dalhousie University in Halifax, Canada. “Obviously we’re doing something different [from other animals], because we’re able to learn language. But it’s not because some little black box evolved specially in our brain that does only language, and nothing else.” Most spoken languages express relationships between the subject and object of a sentence — the “who did what to whom,” Newman says — in one of two ways. Some languages, like English, encode information in word order. “John gave flowers to Mary” means something different than “Mary gave flowers to John.” And “John flowers Mary to gave” doesn’t mean anything at all. © Society for Science & the Public 2000 - 2010

Keyword: Language
Link ID: 13940 - Posted: 06.24.2010

by David Robson AT EINSTEIN's autopsy in 1955, his brain was something of a disappointment: it turned out to be a tad smaller than the average Joe's. Indeed, later studies have suggested a minimal link between brain size and intelligence. It seems brain quality rather than quantity is key. One important factor seems to be how well our neurons can talk to each other. Martijn van den Heuvel, a neuroscientist at Utrecht University Medical Center in the Netherlands, found that smarter brains seem to have more efficient networks between neurons - in other words, it takes fewer steps to relay a message between different regions of the brain. That could explain about a third of the variation in a population's IQ, he says. Another key factor is the insulating fatty sheath encasing neuron fibres, which affects the speed of electrical signals. Paul Thompson at the University of California, Los Angeles, has found a correlation between IQ and the quality of the sheaths (The Journal of Neuroscience, vol 29, p 2212). We still don't know exactly how much genes contribute to intelligence, with various studies coming up with estimates ranging from 40 to 80 per cent. This wide range of estimates might have arisen because genes contribute more to IQ as we get older, according to a study published last year. By comparing the intelligence of 11,000 pairs of twins, Robert Plomin of King's College London found that at age 9, genes explain 40 per cent of the variation, but by 17 they account for roughly two-thirds (Molecular Psychiatry, DOI: 10.1038/mp.2009.55). © Copyright Reed Business Information Ltd.

Keyword: Intelligence; Genes & Behavior
Link ID: 13939 - Posted: 06.24.2010

The autism-spectrum disorders encompass a wide range of symptoms, from social awkwardness to a complete inability to interact and communicate. Here, six men and women speak about living with an autism-spectrum disorder. (Join the discussion here.) Copyright 2010 The New York Times Company

Keyword: Autism
Link ID: 13938 - Posted: 04.05.2010

By Rachel Ehrenberg You don’t need to lead a fly to water to make it drink. A new discovery by neuroscientists helps explain why. Researchers have illuminated the biochemical mechanism that fruit flies use to detect water in their environment. The finding may lead to a better understanding of how all cells control their water content, and perhaps to similar discoveries in people. Researchers report online in Nature April 4 that a protein known as PPK28 helps fruit flies taste water. The protein makes up a channel that spans the membrane of a water-sensing nerve cell in the feeding tube of Drosophila, the fruit fly. PPK28 is from a larger family of channel proteins that includes one mammals use to taste salt. But none had been pegged as a mediator of water flow into cells. It’s possible that related proteins have similar tasks in the cells of mammals, says Charles Bourque of the Centre for Research in Neuroscience at McGill University in Montreal, Canada, who was not involved in the work. Peter Cameron of the University of California, Berkeley and his colleagues identified the water-sensing role of PPK28 by comparing the genes of normal flies to a group whose taste cells had been transformed into touch sensors. The genetics pointed to PPK28 as a likely fly divining rod. When the researchers marked the protein with a fluorescent tag and gave the flies various solutions to drink, PPK28 lit up when the flies tasted water, revealing a “drink me” signal that was going right to their brains. © Society for Science & the Public 2000 - 2010

Keyword: Chemical Senses (Smell & Taste)
Link ID: 13937 - Posted: 06.24.2010

By OLIVIA JUDSON Males and females are different. This is so obvious that, at first, it hardly seems worth pointing out. But in fact, it is remarkable. It is also the cause of a profound sexual tension. The problem is, often, the pressures on males and females are not the same. In the fruit fly Drosophila melanogaster, for example, males must perform an elaborate song-and-dance routine to seduce each female; females, in contrast, must give off a certain smell to be attractive to a male. Females need to eat a high protein diet so as to be able to produce eggs; males can skimp on the proteins. male sage-grouseAssociated Press A strutting male sage-grouse. Among greater sage-grouse, Centrocercus urophasianus, females are smaller than males and have straw-colored feathers. Males have flamboyant feathers and strut and cavort and puff themselves up to seduce females. (The behavior of male and female sage grouse is well known; click here to see a male display.) Needless to say, in this species females do all the childcare: they choose a nest site, sit on the eggs, then feed and protect the chicks. In sum, the traits that make a “good” male are often different from those that make a “good” female. (Note: I’m only talking about “good” in evolutionary terms. That means a trait that improves your chance of having surviving offspring.) Since many of these traits have a genetic underpinning, male and female genes are thus being sculpted by different forces. Copyright 2010 The New York Times Company

Keyword: Evolution; Sexual Behavior
Link ID: 13936 - Posted: 06.24.2010

By JON MOOALLEM The Laysan albatross is a downy seabird with a seven-foot wingspan and a notched, pale yellow beak. Every November, a small colony of albatrosses assembles at a place called Kaena Point, overlooking the Pacific at the foot of a volcanic range, on the northwestern tip of Oahu, Hawaii. Each bird has spent the past six months in solitude, ranging over open water as far north as Alaska, and has come back to the breeding ground to reunite with its mate. Albatrosses can live to be 60 or 70 years old and typically mate with the same bird every year, for life. Their “divorce rate,” as biologists term it, is among the lowest of any bird. When I visited Kaena Point in November, the first birds were just returning, and they spent a lot of their time gliding and jackknifing in the wind a few feet overhead or plopped like cushions in the sand. There are about 120 breeding albatrosses in the colony, and gradually, each will arrive and feel out the crowd for the one other particular albatross it has been waiting to have sex with again. At any given moment in the days before Thanksgiving, some birds may be just turning up while others sit there killing time. It feels like an airport baggage-claim area. Once together, pairs will copulate and collaboratively incubate a single egg for 65 days. They take shifts: one bird has to sit at the nest while the other flaps off to fish and eat for weeks at a time. Couples preen each other’s feathers and engage in elaborate mating behaviors and displays. “Like when you’re in a couple,” Marlene Zuk, a biologist who has visited the colony, explained to me. “All those sickening things that couples do that gross out everyone else but the two people in the couple? . . . Birds have the same thing.” Copyright 2010 The New York Times Company

Keyword: Sexual Behavior
Link ID: 13935 - Posted: 06.24.2010

By Tina Hesman Saey When faced with a choice between carb loading and a protein-rich, Atkins-style diet, honeybees let their guts decide. Insulin signals from fat cells in the bees’ abdomens help determine whether they forage for high-protein pollen or sugar-filled nectar, a new study shows. The study, published April 1 in PLoS Genetics, is the first to manipulate insulin signals in honeybees and to show how changes in the signals influence behavior. Reducing the activity of the insulin receptor substrate, or IRS, gene caused bees to forage more for pollen than for nectar, report researchers led by Gro Amdam, a biologist at Arizona State University in Tempe and the Norwegian University of Life Sciences in Aas. The researchers showed that the gene, which is involved in sugar uptake by cells, regulates not just how nutrients are turned into energy but also the bees’ preferences for which foods to consume in the first place. Reducing the gene’s activity in fat cells affects the bees’ behavior even if the gene is functioning normally in the brain, Amdam’s group discovered. That suggests the gene causes fat cells to generate a chemical signal that tells the brain what kind of food to look for. “That’s something that I find quite remarkable,” says Thomas Flatt, a geneticist at the University of Veterinary Medicine in Vienna, Austria. “I don’t think many people have considered how insulin is affecting food choices, not just what happens after food has entered the body. The behavior dimension is new and interesting.” © Society for Science & the Public 2000 - 2010

Keyword: Obesity
Link ID: 13934 - Posted: 06.24.2010