by Michael Marshall In 1958, Disney released a documentary called White Wilderness, which showed the wildlife of the Arctic on the cinema screen. David Attenborough it ain't. The film is now notorious for containing faked footage of something that simply doesn't happen: lemmings committing suicide en masse. Realising that the Arctic rodents did not collectively top themselves, the film-makers resorted to trickery. After producing footage of the lemmings migrating by placing them on a snow-covered turntable, they shipped some of them to a cliff overlooking a river and herded them over the edge. The resulting footage (available on YouTube and still shocking today) shows hordes of lemmings plummeting off a cliff, with the culpable humans studiously out of frame. It helped cement the myth of lemming mass suicide in popular culture. Yet had the film-makers looked a little closer, they would have found that lemmings really are bizarre creatures. Finally, the true nature of lemming behaviour is being revealed. Lemmings are small rodents, related to hamsters, gerbils and mice. There are over 20 species, all found in the far north, including Canada, Scandinavia and Russia. Unlike many Arctic animals, lemmings do not hibernate through the winter. Instead, they forage along runs and tunnels dug beneath the snow layer. This allows them to carry on breeding even as temperatures drop to -20 °C, driving the population up. In most species the population grows for three years, then crashes to near-extinction in the fourth. © Copyright Reed Business Information Ltd.

Keyword: Stress; Sexual Behavior
Link ID: 14598 - Posted: 10.28.2010

By The Editors Nearly 20 years ago a small study advanced the notion that listening to Mozart’s Sonata for Two Pianos in D Major could boost mental functioning. It was not long before trademarked “Mozart effect” products appealed to neurotic parents aiming to put toddlers on the fast track to the Ivy League. Georgia’s governor even proposed giving every newborn there a classical CD or cassette. The evidence for Mozart therapy turned out to be flimsy, perhaps nonexistent, although the original study never claimed anything more than a temporary and limited effect. In recent years, however, neuroscientists have examined the benefits of a concerted effort to study and practice music, as opposed to playing a Mozart CD or a computer-based “brain fitness” game once in a while. Advanced monitoring techniques have enabled scientists to see what happens inside your head when you listen to your mother and actually practice the violin for an hour every afternoon. And they have found that music lessons can produce profound and lasting changes that enhance the general ability to learn. These results should disabuse public officials of the idea that music classes are a mere frill, ripe for discarding in the budget crises that constantly beset public schools. Studies have shown that assiduous instrument training from an early age can help the brain to process sounds better, making it easier to stay focused when absorbing other subjects, from literature to tensor calculus. The musically adept are better able to concentrate on a biology lesson despite the racket in the classroom or, a few years later, to finish a call with a client when a colleague in the next cubicle starts screaming at an underling. They can attend to several things at once in the mental scratch pad called working memory, an essential skill in this era of multitasking. © 2010 Scientific American

Keyword: Hearing; Attention
Link ID: 14597 - Posted: 10.28.2010

By Colm O'Dushlaine The psychologist Rollo May once described depression as “the inability to construct a future”. According to the National Institute for Mental Health this “inability” can affect up to 14.8 million Americans – 7% of the population – in a given year, at an annual cost of $100 billion. That’s about five times the renewable energy budget of the United States. We hear many things about how great we’re getting at saving the planet with our hybrids and off-shore wind farms; we hear far less about how we’re doing in combating or preventing depression. This month, however, has brought some potentially exciting news: two genetic studies with major ramifications for the treatment and diagnosis of Major Depressive Disorder. As a psychiatric geneticist, it is rare that I see such clear insights into distinct genetic mechanisms of psychiatric illnesses. Research into bipolar disorder and schizophrenia –- the disorders I spend most of my time working on –- would benefit a great deal from breakthrough studies such as these. One new study, published in Nature Medicine, suggests that a pathway called MAPK – and one gene in particular from this pathway, MPK-1 – are significantly dysregulated in certain areas of the brains of individuals with major depression. These results were obtained by looking for significant gene expression changes in post-mortem brains from 21 individuals with Major Depressive Disorder compared to 18 matched controls. The researchers, led by Yale’s Vanja Duric, confirmed their results in rat and mouse models. And they showed that not only did raising MPK-1 levels lead to depressive symptoms, but that antidepressant treatment reduced the expression of MPK-1. © 2010 Scientific American, a Division of Nature America, Inc.

Keyword: Depression; Genes & Behavior
Link ID: 14596 - Posted: 10.28.2010

by Carl Zimmer In some of the world’s oldest medical texts­­—papyrus scrolls from ancient Egypt, clay tablets from Assyria—people complain about noise in their ears. Some of them call it a buzzing. Others describe it as whispering or even singing. Today we call such conditions tinnitus. In the distant past, doctors offered all sorts of strange cures for it. The Assyrians poured rose extract into the ear through a bronze tube. The Roman writer Pliny the Elder suggested that earthworms boiled in goose grease be put in the ear. Medieval Welsh physicians in the town of Myddfai recommended that their patients take a freshly baked loaf of bread ($) out of the oven, cut it in two, “and apply to both ears as hot as can be borne, bind and thus produce perspiration, and by the help of god you will be cured.” Early physicians based these prescriptions on what they believed tinnitus to be. Some were convinced it was caused by wind that got trapped inside the ear and swirled around endlessly, so they tried to liberate the wind by drilling a hole into the bones around the ear or using a silver tube to suck air out of the ear canal. The treatments didn’t work, but they did have an internal logic. Today tinnitus continues to resist medicine’s best efforts, despite being one of the more common medical disorders. Surveys show that between 5 and 15 percent of people say they have heard some kind of phantom noise for six months or more; some 1 to 3 percent say tinnitus lowers their quality of life. Tinnitus can force people to withdraw from their social life, make them depressed, and give them insomnia. © 2010, Kalmbach Publishing Co.

Keyword: Hearing
Link ID: 14595 - Posted: 10.28.2010

By Laura Sanders Using nothing but thoughts, people can coax a brain cell that likes Marilyn Monroe to overpower a Josh Brolin–favoring cell in a dominance battle that brings her image up on a computer screen, a study appearing October 28 in Nature shows. The paper expands on data presented last year at the Society for Neuroscience’s annual meeting in Chicago (SN: 11/21/09, p. 9) and shows how the brain makes choices about what to pay attention to in a sensory-rich world. Study coauthor Moran Cerf and his colleagues eavesdropped on single neurons with electrodes that had already been implanted for medical reasons in the brains of people with epilepsy. These cells fired when the person saw particular people, places or things, such as the Eiffel tower, Bill Clinton or bananas. The team set up neuron contests by linking cell recordings to a computer that flashed images on a screen. In one trial, a Monroe neuron and a Brolin neuron went head to head as a person saw a hybrid mashup of the two stars’ pictures. Each time the Monroe neuron fired, her image would get brighter, and when the Brolin neuron fired, his image would get brighter. Researchers told the participant which person was the target, and watched as the neurons duked it out. In most trials, subjects quickly became experts at causing neurons to fire with their thoughts alone, even when faced with a “distractor” image, says Cerf, who conducted the research while at Caltech but is now at New York University. © Society for Science & the Public 2000 - 2010

Keyword: Attention
Link ID: 14594 - Posted: 10.28.2010

Scans appear to show differences in brain functioning in women with persistently low sex drives, claim researchers. The US scientists behind the study suggest it provides solid evidence that the problem can have a physical origin. They measured brain activity as the women watched erotic videos. But a spokesman for the charity Relate said the study simply demonstrated low libido at work in the brain, rather than exposing its cause. In recent years, a diagnosis of "hypoactive sexual desire disorder" (HSDD) in women has become more accepted by science. However, there remains controversy about whether the term can or should be used to describe a lack of sexual desire, which may be caused by a variety of psychological, emotional and physical factors. The latest study, carried out at Wayne State University in Detroit and presented to the American Society for Reproductive Medicine conference in Denver, highlights differences in mental processing in women who have low sex drives. Its author, Dr Michael Diamond, said it suggested that HSDD was a genuine physical problem. BBC © MMX

Keyword: Sexual Behavior
Link ID: 14593 - Posted: 10.26.2010

By Steve Connor, Science Editor People who are able to sleep for just a few hours each night without nodding off at their desks the following day owe their apparently superhuman ability to stay awake to variations in their genes, a study has suggested. Winston Churchill, Margaret Thatcher and Bill Clinton were all famous for managing on just five or six hours' sleep a night, rather than the customary eight. Napoleon Bonaparte, Michelangelo and Florence Nightingale apparently got by on four hours, as does Madonna and the American chat-show host Jay Leno. Sleep researchers have known that different people have different sleep patterns, with some individuals – known as "owls" – being more active and alert in the evenings, while others – known as "larks" – are early risers. It is also known that as people get older they tend to develop more disturbed sleep patterns. Studies suggest that older people need as much sleep as younger people, but sleep in bouts rather than as a single, long snooze. Trying to understand why people vary in the amount of sleep they need led to a study of 37 healthy adults who carry a variant in their DNA that has already been linked with sleep disturbances. The study compared them against 92 equally healthy people who did not carry the genetic variant, known as DQB1*0602. All took part in tests in a sleep laboratory at the University of Pennsylvania School of Medicine in Philadelphia. For the first two nights they spent 10 hours in bed and were fully rested. For the next five nights they were subjected to chronic partial sleep deprivation where they were only allowed to sleep for four hours a night. The rest of the time they were kept awake with the lights on. ©independent.co.uk

Keyword: Sleep; Genes & Behavior
Link ID: 14592 - Posted: 10.26.2010

People who smoke heavily in middle age seem to more than double their risk of Alzheimer's disease and other forms of dementia late in life, research suggests. Smoking is a well-established risk factor for stroke, but the link between smoking and risk of Alzheimer's and other types of dementia has been less clear since heavy smokers often die from other ailments before smoking's toll on the brain is evident. To find out more, Dr. Minna Rusanen of the University of Eastern Finland in Kuopio and colleagues analyzed data from 21,123 people in California who participated in a survey between 1978 and 1985. When the study began, the participants were between 50 and 60 years old, and they were tracked for an average of 23 years of followup. During that time, 5,367 participants or 25 per cent were diagnosed with dementia, including 1,136 with Alzheimer's disease and 416 with vascular dementia, the researchers found. Compared with non-smokers, those smoking more than two packs a day had 2.14 times higher risk of dementia 2.57 times higher risk of Alzheimer's, and 2.57 times higher risk of vascular dementia — another common and sometimes overlapping cause of progressive deterioration of memory and thinking. "This study shows that the brain is not immune to the long-term consequences of heavy smoking," said the study's principal investigator, Rachel Whitmer, a research scientist with the Kaiser Permanente Division of Research in Oakland, Calif. © CBC 2010

Keyword: Alzheimers; Drug Abuse
Link ID: 14591 - Posted: 10.26.2010

By Sandra G. Boodman Right away, Lori White knew that something was very wrong. The 44-year-old legal assistant at a Northern Virginia law firm had been working out with a personal trainer at her gym, executing a demanding and unfamiliar move. As she pulled down on a bar equipped with weights while simultaneously lunging forward, she felt an explosive pop in her head, immediately followed by a headache more crushing than any she had previously experienced. For the next 10 minutes, White recalled, she sat on the floor, clutching her head and fearing she would throw up or pass out. To her relief, the pain receded within a few hours. "I figured I'd just strained something," she recalled. But within weeks of the 2005 episode, an alarming new problem surfaced: stabbing pains lasting five to 30 seconds in the front of her head, similar to the "brain freeze" that people sometimes experience while eating ice cream. It took White three years to discover what had happened that day in the gym and two more to sort out what should be done about it - a confusing and sometimes contradictory process that involved specialists in the Washington area as well as Baltimore and Charlottesville. Two weeks ago at Georgetown University Hospital, White underwent treatment that doctors hope will cure her problem. © 2010 The Washington Post Company

Keyword: Pain & Touch
Link ID: 14588 - Posted: 10.26.2010

Movement in our field of vision can drastically affect the way our brain perceives the world around us. To explain these phenomena, visual researchers have come up with some mind-bending new motion perception illusions. Here, New Scientist brings you our pick of the best. © Copyright Reed Business Information Ltd.

Keyword: Vision
Link ID: 14587 - Posted: 10.26.2010

By Rachel Ehrenberg Inhaling a blast of bitter fumes sends a breathe-easy message to the lungs, a new study shows. Stimulating bitterness receptors in the lungs relaxes and opens the airways, a counterintuitive finding that could lead to new asthma medications, scientists report online October 24 in Nature Medicine. Bitter-taste receptors just like the ones on the tongue abound on the smooth muscle tissue that wraps around the airway tubes leading to the lungs, reports a team from the University of Maryland and Johns Hopkins in Baltimore. In mice bred to have asthma, inhaled bitter compounds such as quinine did a better job of relaxing airways than did the standard asthma drug albuterol. These bitter-taste receptors in lung muscles should be good targets for new asthma medications that are based on the multitude of molecules known to stimulate bitter receptors, says Mathur Kannan, a pharmacologist in the College of Veterinary Medicine at the University of Minnesota in St. Paul. The relaxation response to bitter-flavored air remains somewhat puzzling. In the mouth, bitter receptors are part of the body’s first line of defense against possibly poisonous compounds. Cells lining the upper part of the respiratory tract also have bitter-taste receptors, scientists reported earlier this year. But there, they can trigger an “out, out” reaction, stimulating the featherlike cilia of the airways to push whatever’s nearby up and away. So it seemed more logical that muscles controlling air flow to lungs would constrict when stimulated by potential toxins, says Stephen Liggett of the University of the Maryland School of Medicine in Baltimore, who led the new work. © Society for Science & the Public 2000 - 2010

Keyword: Chemical Senses (Smell & Taste)
Link ID: 14586 - Posted: 10.26.2010

Roger Dobson At school they are more popular, have more friends and are less likely to be bullied. And as adults, they have more sexual partners, and are more likely to be married, have a good job, and earn a higher salary – around 10 per cent more than plain Joes and Janes. They are also perceived to be healthier, smarter, and more trustworthy, and if they go into politics they are more likely to be elected. But why are some people seen as attractive and others not? And why have we evolved to find some features attractive and others not? According to new research, it may all be down to oxidative stress and antioxidants. Psychologists have discovered that men who were rated as the most physically attractive by women have the lowest levels of markers of oxidative stress. "These findings have several important implications," says psychologist Dr Steven Gangestad who led the study. "They fit in with the idea that women evolved to find particular features attractive because those features are related to low levels of oxidative stress." Attractiveness has long been a source of fascination for psychologists, anthropologists, behavioural scientists – and singletons. Some have investigated the many life advantages that come with attractiveness, while others have looked at whether or not it is a learned criterion. One school of thought has it that attraction to specific features is not learned, but has evolved over time as a way of distinguishing the virile from the weak. This evolutionary theory is backed up by much research, including studies showing that newborn babies have a preference for attractive faces. It's suggested that physical attractiveness may serve as a biological signal of good health. In ancestral time, being able to spot an attractive, and therefore fit, partner would have carried a huge survival advantage. ©independent.co.uk

Keyword: Sexual Behavior; Evolution
Link ID: 14585 - Posted: 10.26.2010

By Floyd Skloot Oliver Sacks published his first book, “Migraine,’’ 40 years ago. A provocative mixture of scholarship, personal experience, and case studies, it approached the malady as experience rather than illness, viewing the patient in full human dimension and not simply a collection of symptoms, signs, and test results. The book showed Sacks’s gifts, even at the start of his career, for accurate description and fresh prose, such as his characterization of migraine’s hallucinatory aura as a “dance of brilliant stars, sparks, flashes.’’ Over his long career as a neurologist and writer, Sacks has addressed a range of subjects: “Awakenings’’ (1973) dealt with patients immobilized and silenced by sleeping sickness who were briefly returned to active function by the administration of a drug that failed to sustain its benefits; “Seeing Voices’’ (1989) was a journey into the world of the deaf; “Musicophilia’’ (2007) concerned the human passion for music. In all his work, Sacks has been fascinated by how the brain’s failures of function, its neuro-strangenesses, reveal essential truths about what makes us human. His books are populated by people — those with autism or Tourette syndrome or aphasia — whose experiences with and adaptations to neurological problems encourage us to think about our own perceptions of the world. From those earliest studies of migraine through his accounts of misperception in “The Man Who Mistook His Wife for a Hat’’ (1985) and congenital colorblindness in “The Island of the Colorblind’’ (1997), Sacks has returned to the subject of sight and the neurology of visual perception. Now in “The Mind’s Eye,’’ his 11th book, Sacks takes on the subject fully, offering seven essays about vision and what it is like when the sense of sight is radically changed or lost because of neurological damage. His exploration of this subject is deepened by personal experience, as Sacks’s own visual health becomes compromised. © 2010 NY Times Co.

Keyword: Vision
Link ID: 14584 - Posted: 10.26.2010

by Jessica Hamzelou Neurologists have found that the brain plaques associated with Alzheimer's can form when the proteins responsible are injected into the bellies of mice, suggesting that the guilty proteins can get from the body's periphery to wreak havoc in the brain. A protein called beta-amyloid makes up the brain plaques that accompany the disease. In 2006, Lary Walker at Emory University in Atlanta, Georgia, Mathias Jucker at the University of Tübingen in Germany and colleagues found that they could trigger Alzheimer's-like plaques by injecting samples of plaque-ridden brains into the brains of healthy mice. Now, Jucker and his colleagues at Tübingen have managed to create the same brain plaques by injecting the tissue elsewhere in the bodies of mice. The group used mice genetically modified to produce large amounts of beta-amyloid, meaning they develop brain plaques similar to those seen in Alzheimer's disease in people. When the mice were around 2 years old, the team removed some of their beta-amyloid-laden brain tissue and injected it into the peritoneum – the lining of the abdomen – of young transgenic mice. Another group of transgenic mice received an injection of healthy brain tissue from normal mice of the same age that had not developed plaques. Seven months later, before the mice had had a chance to develop plaques of their own accord, the team looked at the their brains. The mice injected with healthy brain tissue had normal-looking brains, but those injected with beta-amyloid-heavy tissue had developed full-blown plaques similar to those seen in people with Alzheimer's. © Copyright Reed Business Information Ltd.

Keyword: Alzheimers
Link ID: 14583 - Posted: 10.23.2010

By Emily Sohn New moms may feel their brain cells dying with every cumulative hour of sleep loss. But a new study offers hope. In the first months after giving birth, the study found, parts of a mother's brain may actually grow. Even better news, doting mamas who gushed the most about how special and perfect their babies were showed the most growth. The parts of the brain that grew are involved in motivation, reward behavior and emotion regulation. That suggests that, by reshaping itself, the post-partum brain motivates a mother to take care of her baby, and then feel happy and rewarded when she does. The findings may eventually help women who feel disconnected from their babies or even hostile toward them in the early months, said lead author Pilyoung Kim, a developmental psychologist, now at the National Institutes of Mental Health in Bethesda, Md. "We could maybe compare brain changes in mothers who were depressed or had problems bonding with their infants to normal mothers," said Kim, who was at Yale University when she did the work. "And we might be able to develop some kind of intervention programs to help mothers feel more rewarded about their parenting and their baby." During pregnancy and the post-partum period, women often feel their brains turning to mush. New moms report that they have trouble remembering things that they used to remember easily. It's such a common phenomenon that women often call it "Mommy Brain." Some research has even shown that women's brains shrink slightly during pregnancy. © 2010 Discovery Communications, LLC

Keyword: Sexual Behavior
Link ID: 14582 - Posted: 10.23.2010

by Patricia Churchland WHERE do moral values come from? Not from Plato's heaven, nor from any other. Aristotle, Confucius and Darwin all recognised valuing as a basic function of biological creatures generally, and moral valuing as a basic function of highly social and intelligent animals like humans. Until very recently, however, science could not explain how brains, built by gene networks interacting with the environment, give rise to morality. Natural selection being what it is, caring for others must serve the fitness of the animals involved. Evolutionary biologists have developed models to show how this might work, but it is only now that neuroscientists are catching the first glimpses of how altruistic behaviour happens in the brain. Morality seems to be shaped by four interlocking brain processes: caring, rooted in attachment to and nurture of offspring; recognition of others' psychological states, bringing the benefit of predicting their behaviour; problem-solving in a social context, such as how to distribute scarce goods or defend the clan; and social learning, by positive and negative reinforcement, imitation, conditioning and analogy. These factors result in the emergence of a conscience: a set of socially sanctioned responses to prototypical circumstances. © Copyright Reed Business Information Ltd.

Keyword: Emotions
Link ID: 14581 - Posted: 10.23.2010

by Martha J. Farah We have long known that moral character is related to brain function. One remarkable demonstration of this was provided by Phineas Gage, a 19th-century construction foreman injured in an explosion. After a large iron rod was blown through his head, destroying bits of his prefrontal cortex, Gage was transformed from a conscientious, dependable worker to a selfish and erratic character, described by some as antisocial. Recent research has shown that psychopaths, who behave antisocially and without remorse, differ from the rest of us in several brain regions associated with self-control and moral cognition (Behavioral Sciences and the Law, vol 26, p 7). Even psychologically normal people who merely score higher in psychopathic traits show distinctive differences in their patterns of brain activation when contemplating moral decisions (Molecular Psychiatry, vol 14, p 5). The idea that moral behaviour is dependent on brain function presents a challenge to our usual ways of thinking about moral responsibility. A remorseless murderer is unlikely to win much sympathy, but show us that his cold-blooded cruelty is a neuropsychological impairment and we are apt to hold him less responsible for his actions. Presumably for this reason, fMRI evidence was introduced by the defence in a recent murder trial to show that the perpetrator had differences in various brain regions which they argued reduced his culpability. Indeed, neuroscientific evidence has been found to exert a powerful influence over decisions by judges and juries to find defendants "not guilty by reason of insanity" (Behavioral Sciences and the Law, vol 26, p 85). © Copyright Reed Business Information Ltd.

Keyword: Emotions
Link ID: 14580 - Posted: 10.23.2010

By Amanda Chan If you're a guy who finds it hard to talk about your feelings, the problem might lie with your testosterone levels, a recent study suggests. A psychological condition called alexithymia is found in people who have an extraordinarily difficult time conveying emotions to others and interpreting others' feelings. Past studies have shown that alexithymia and depression are closely related, and the condition has long been associated with aging. Depression, low testosterone and erectile dysfunction are all known to become more common in men as they age. Researchers from Finland wanted to see if alexithymia is a result of aging itself, or if it is actually caused by other factors that typically come with aging, like a lower sex drive. In the study, nearly 1,400 men ages 25 to 65 filled out questionnaires during a three-year period, beginning in 1998, and reported difficulties they had in expressing thoughts and emotions, symptoms of depression and general life-satisfaction levels. Out of those 1,400 men, researchers chose 116, half who had symptoms of alexithymia and half who did not, and asked them to complete a follow-up survey and report their alcohol intake, smoking status, and other information, and were also given a blood test to check their testosterone levels, said study researcher Kirsi Honkalampi, a professor at the Kuopio Psychiatric Center in Finland. MyHealthNewsDaily Copyright © 2010.

Keyword: Hormones & Behavior; Emotions
Link ID: 14579 - Posted: 10.21.2010

By Carolyn Y. Johnson The black-and-white brain scans that have become a routine part of medicine reveal a curved gray structure folded around large lakes of white — a map that helps doctors diagnose, treat, and understand disease. But to some scientists, these images are crude and incomplete, akin to medieval maps of the world in which unexplored regions were filled in with sea monsters or dragons. “It’s like there’s a continent there, and we are nibbling along the shores,’’ said Dr. Van Wedeen, a physicist and radiologist at the Martinos Center for Biomedical Imaging at Massachusetts General Hospital. He is helping to lead an effort to develop a superscanner that can reveal that unknown territory and provide new insight into the brain. On a recent morning, Wedeen pulled up images created with the new technology, in which the lakes of white were crisscrossed by colorful, ropy bundles of fibers, revealing an elegant, three-dimensional architecture. Looking more like art than anatomy, these strands form the connections in the brain — the “connectome.’’ They are neural highways crucial for brain function, including thoughts, movements, and sensations. “This isn’t just statistical stuff, or mush, or steel wool, or chaotic spaghetti,’’ Wedeen said. “This is as important a structure as you’re ever going to meet, and this thing had to be designed by evolution.’’ © 2010 NY Times Co.

Keyword: Brain imaging
Link ID: 14578 - Posted: 10.21.2010

by Sara Reardon A pregnant mom who regularly chows down on cheeseburgers probably isn't doing her baby any good; she may even predispose him to obesity, according to some studies. But when pediatrician Sheau-Fang Ng noticed that her chubby child patients tended to have not just one but two overweight parents, she began to wonder: Could dad's habits be weighing in, too? She and her colleagues have now found the first direct evidence that a father's diet, not just his genes, can increase his offspring's risk of diabetes and other diseases, at least in rats. In a simple experiment, the researchers—based at the University of New South Wales in Sydney, Australia—fed normal male rats a diet consisting of more than 40% fat, the rodent equivalent of vending machine food. The animals quickly became obese. The rats' daughters, born from mothers of normal weight and fed a healthy diet, weren't fat, but they did show early signs of diabetes by the time they reached puberty. Not only did their insulin levels fail to rise in response to high glucose, the team reports online today in Nature, but their insulin-producing islet cells in the pancreas also expressed very different genes than do normal islet cells. In addition, many of the daughters were underweight at birth, which, in humans, often foretells obesity later in life. Sons of fat fathers showed some signs of diabetes, too, but to a much lesser extent than their sisters. Lead author Margaret Morris believes that the sons, too, would likely develop symptoms as they age or if they were fed a high-fat diet. © 2010 American Association for the Advancement of Science.

Keyword: Obesity; Development of the Brain
Link ID: 14577 - Posted: 10.21.2010