by Carl Zimmer Imagine that an eccentric psychologist accosts you. In his hand is a piece of paper with 20 pictures of roses. One of the pictures shows a rose in the flower bed you just passed, he says, and he asks you to pick its picture out from his lineup. The challenge would seem absurd—but if you were to change the roses to faces, nearly everyone could meet it. Most of us have a powerful ability to recognize faces, and yet we hardly ever take note of it. We can commit a face to memory with a single viewing, and even if we see that face only once its memory can stay fresh for years. The faces we remember so easily may differ only in subtle tweaks of geometry: the ratio of distances between different landmarks such as the eyes and the mouth, for example. A small fraction of people, however, cannot recognize faces—even the faces of their parents, spouses, and children. Prosopagnosia, as this condition is known, can affect people from birth or be triggered later in life by injuries to the brain. It strikes an estimated 2 percent of Americans and is often accompanied by other types of recognition impairments, including difficulty recognizing places and objects, such as cars. Despite the millions of people who suffer from prosopagnosia, it remains an obscure disorder, probably due to the skill with which face-blind people quietly compensate for their condition. In his new book, The Mind’s Eye (Amazon; book review in The New York Times), neurologist and writer Oliver Sacks makes the surprising disclosure that he has prosopagnosia. © 2011, Kalmbach Publishing Co.

Keyword: Attention; Laterality
Link ID: 14889 - Posted: 01.21.2011

By Kevin Mitchell What if your brain knew something but couldn’t tell you? New research suggests that this is exactly what may be behind two rather curious conditions. Most of us are familiar with people who are tune deaf – these are the people who not only cannot sing in tune but are also unaware of that fact. Individuals with severe forms of this condition, known as amusia, are unable to detect whether particular notes within a melody are out of tune or out of key. Many are also unable to recognise melodies without lyrics or to hold a tune in their heads, even if they have just heard it. These difficulties arise despite normal hearing and also a fairly normal ability to hear the difference between isolated tones. The defect lies in connecting this sensory input with some implicit knowledge of musical structure and contours. Amusia thus falls into a class of conditions known as agnosias, which are characterised by the lack of knowledge of some, often very specific, category of object. Another, equally curious, example of this class of condition is prosopagnosia – the lack of knowledge of faces. People with severe prosopagnosia may be completely unable to recognise the faces of famous people, friends, loved ones, even their own faces. As with amusia, this reflects a high-level deficit – people with prosopagnosia have normal vision and the ability to distinguish specific facial features, gender, even facial emotions. Both conditions thus seem to reflect the inability to link incoming sensory information (a person’s face or a specific note) with stored, implicit knowledge about that category (the person’s identity or a specific melody or general rules of melodic stucture). © 2011 Scientific American, a Division of Nature America, Inc.

Keyword: Hearing; Attention
Link ID: 14888 - Posted: 01.21.2011

By NICHOLAS WADE Chaser, a border collie who lives in Spartanburg, S.C., has the largest vocabulary of any known dog. She knows 1,022 nouns, a record that displays unexpected depths of the canine mind and may help explain how children acquire language. Chaser belongs to John W. Pilley, a psychologist who taught for 30 years at Wofford College, a liberal arts institution in Spartanburg. In 2004, after he had retired, he read a report in Science about Rico, a border collie whose German owners had taught him to recognize 200 items, mostly toys and balls. Dr. Pilley decided to repeat the experiment using a technique he had developed for teaching dogs, and he describes his findings in the current issue of the journal Behavioural Processes. He bought Chaser as a puppy in 2004 from a local breeder and started to train her for four to five hours a day. He would show her an object, say its name up to 40 times, then hide it and ask her to find it, while repeating the name all the time. She was taught one or two new names a day, with monthly revisions and reinforcement for any names she had forgotten. Border collies are working dogs. They have a reputation for smartness, and they are highly motivated. They are bred to herd sheep indefatigably all day long. Absent that task, they must be given something else to do or they go stir crazy. Chaser proved to be a diligent student. Unlike human children, she seems to love her drills and tests and is always asking for more. “She still demands four to five hours a day,” Dr. Pilley said. “I’m 82, and I have to go to bed to get away from her.” © 2011 The New York Times Company

Keyword: Language; Evolution
Link ID: 14887 - Posted: 01.18.2011

Obesity is one the last forms of discrimination that society readily accepts, and that's no laughing matter, a Canadian summit heard Monday. The Canadian Obesity Network, an advocacy group that organized the conference in Toronto, is considering calling for federal legislation that would make it illegal for employers to discriminate against overweight Canadians, a move the state of Michigan has made. The network brought together some of North America's top obesity experts and people who struggle with weight issues in what the network says is the first Canadian conference to deal with weight bias and discrimination. Summit participant David Dolomont said he weighs more than 300 pounds and has faced taunts and jokes about his excess weight since childhood. "My mother would have to take me to that special store downtown to buy pants because I had to get into the so called 'husky size,' Dolomont recalled when he spoke about his experience at the conference. The discrimination didn't end with adulthood when he started to work as a paramedic in Hamilton, he said. Dolomont remembers feeling ashamed and embarrassed during a breakfast at work where he was singled out by a supervisor. "He saw me and then come over right away and said, 'Hey David glad you're here. We knew you were coming this morning so we asked them to put on a second cook and get some extra food in just because we knew you were going to be here today." © CBC 2011

Keyword: Obesity
Link ID: 14886 - Posted: 01.18.2011

A person's friends tend to share certain genes in common with each other — but not always with the individual, a new study suggests. "People’s friends may not only have similar traits, but actually resemble each other on a genotypic level," said the study led by James Fowler, a geneticist at the University of California at San Diego. The findings were published Friday in the Proceedings of the National Academy of Sciences. Researchers noticed two distinct patterns within social networks when it came to the genes DRD2, which has been linked to alcoholism, and CYP2AP, which is linked with the character trait of openness. In the case of DRD2, people with the marker tend to make friends with those who also have that marker. People without it tend to make friends with other DRD2-negative individuals. In the case of CYP2A6, the person who has the gene tends to be the hub of a social network made up of people who don't have it and instead share the opposite genotype. Four other genes examined by the researchers did not show such patterns among groups of friends. The analysis found that this gene clustering within social networks was apparent even when the researchers took into account the fact that people are more likely to make friends with people who live near them. The findings suggest that studies linking certain traits to genes may be biased in ways that were not previously anticipated. © CBC 2011

Keyword: Genes & Behavior
Link ID: 14885 - Posted: 01.18.2011

* Jonathan Leake LIFE really is unfair. Researchers have found that handsome men and beautiful women tend to be cleverer, with IQs averaging up to nearly 14 points above the norm. The finding, based on studies in Britain and America, suggests that the stereotype of blondes or good-looking men being dimmer than average needs to be revised. Instead it seems that evolution favours the already blessed, rewarding attractive people with partners who are not just good-looking but intelligent too. The research, by the London School of Economics, suggests that since both beauty and intelligence tend to be inherited, the children of such couples will end up with both qualities, building a genetic link between them. This link then becomes reinforced with successive generations. “Both in the British and American samples, physical attractiveness is significantly positively associated with general intelligence, both with and without controls for social class, body size, and health,” said Satoshi Kanazawa, the LSE researcher who carried out the research. “The association between physical attractiveness and general intelligence is also stronger among men than among women.” Dr Kanazawa found that in Britain men who are physically attractive have IQs an average 13.6 points above the norm, whereas physically attractive women are about 11.4 points higher than average. Copyright 2011 News Limited.

Keyword: Intelligence; Genes & Behavior
Link ID: 14884 - Posted: 01.18.2011

By Jesse Bering Women, gather round, read carefully, because this gay man—who once, long ago, feigned sexual interest in your bodies—is about to shine a spotlight on some hidden truths about your natural design. It's by no means a perfect system, but evolution has endowed you with some extraordinary, almost preternatural abilities to prevent your own sexual assault. And these abilities are especially pronounced when you're ovulating. Although it can certainly take other forms, rape will be defined throughout this article as the use of force, or threat of force, to achieve penile-vaginal penetration of a woman without her consent. Whether or not human males evolved to rape women is, to put it mildly, a controversial topic. The flames were fanned especially with the publication, about a decade ago, of Randy Thornhill and Craig Palmer's A Natural History of Rape, which presented evidence of what appear to be biological adaptations in human males (as well as males of many other species) specialized for forcibly coercing females into copulation. They argued that rape is an adaptive behavior in certain contexts; for example, when consensual partners are unavailable. There is some evidence that convicted rapists are physically unattractive, at least as judged by women on the basis of their mug shots. And spousal rape is most likely to occur when the husband finds out (or suspects) his wife has been unfaithful, suggesting that he is attempting to supplant another man's seed. (In fact, the distinctive, mushroom-capped shape of the human penis is designed to perform the specialized function of removing competitors' sperm, which indicates an ancestral history of females having sex with multiple males within a 24-hr period.) Furthermore, UCLA psychologist Neil Malamuth and his colleagues found that one-third of men admit that they would engage in some type of sexual coercion if they could be assured they would suffer no negative consequences, and many report having related masturbatory fantasies. © Copyright 2011 Washington Post.Newsweek Interactive Co. LLC

Keyword: Sexual Behavior; Evolution
Link ID: 14883 - Posted: 01.18.2011

by Linda Geddes Sammy Maloney was a healthy, outgoing 12-year-old, who played in the school band, and liked nothing better than to dump his backpack after school and hang out with his friends in Kennebunkport, Maine. Then, in 2002, Sammy's personality began to change. "The first thing I noticed was that he was walking around the backyard with his eyes closed," says Sammy's mother, Beth Maloney. "I asked him what he was doing, and he said he was memorising." The next day, Sammy was again walking with his eyes closed and would only use the back door. Then he progressed to holding his breath while doing it, only wearing certain coloured clothes, and refusing to allow the windows to be opened, or the lights to be switched off. "Every single day was a new behaviour," says Beth. "We went from baseline to completely dysfunctional within a period of four to six weeks." Sammy was diagnosed with obsessive compulsive disorder, and then Tourette's syndrome. When he continued to deteriorate, a friend suggested testing Sammy for streptococcus - a common childhood bacterial infection that usually causes no more than a sore throat. "By this point he was totally emaciated and he was covered with scabs from scratching himself," says Beth. Sammy hadn't shown any signs of streptococcal infection, but it turned out he was infected. When doctors prescribed antibiotics, his symptoms began to improve. Within a few weeks he was playing board games with his brothers. "After six months of treatment, I knew that he would recover," says Beth. © Copyright Reed Business Information Ltd.

Keyword: OCD - Obsessive Compulsive Disorder; Tourettes
Link ID: 14882 - Posted: 01.18.2011

By NANCY STEARNS BERCAW My father knew it was coming. Alzheimer’s disease had been on his radar ever since his own father died of it. Witnessing the catastrophic deterioration of a man who had been sharp enough to work for Gen. Douglas MacArthur, my frightened father was inspired to become a neurologist. Perhaps the pursuit of medicine could stave off what he believed was a genetic inevitability. As an ever-present reminder of that threat, he kept an atrophied brain in a jar on his desk. That brain, I recently discovered, belonged to his father. As my father approached middle age he began to experiment on himself, with diet supplements. By age 60 he was taking 78 tablets a day. He tracked down anything that offered the possibility of saving brain cells and killing free radicals: Omega 3s, 6s, 9s; vitamins E and C; ginkgo biloba, rosemary and sage; folic acid; flaxseed. After retiring from his neurology practice in Naples, Fla., he spent hours a day doing math. Even when I was visiting, he’d sit silently on his leather recliner with a calculator to verify the accuracy of calculations he did by memory. “What are you saving your mind for, Dad?” I often wondered to myself. “I’m here now, waiting to talk with you.” On one of these occasions, he suddenly looked up from his Sudoku game and stared at me. “Promise me something, gal,” he said. “Anything,” I answered. “Swear on your grandmother’s Bible that you will put a gun to my head if I wind up like my father.” He was dead serious. © 2011 The New York Times Company

Keyword: Alzheimers
Link ID: 14881 - Posted: 01.18.2011

Having the lights on before bedtime could result in a worse night's sleep, according to a study to be published in the Journal of Endocrinology and Metabolism. The research shows that the body produces less of the sleep hormone melatonin when exposed to light. Sleep patterns have been linked to some types of cancer, blood pressure and diabetes. The US researchers also found lower melatonin levels in shift workers. Lifestyles may have moved on from a day/night rhythm, but it seems the human body has not. The pineal gland produces melatonin through the night and starts when darkness falls. Researchers have shown that switching on lights in the home switches off the hormone's production. In the study, 116 people spent five days in room where the amount of light and sleep was controlled. They were awake for 16 hours and asleep for eight hours each day. Initially the patients were exposed to 16 hours of room light during their waking hours. They were then moved onto eight hours of room light in the morning and eight hours of dim light in the evening. The researchers found that electrical light between dusk and bedtime strongly suppressed melatonin levels. With dim light, melatonin was produced for 90 minutes more a day. BBC © MMXI

Keyword: Biological Rhythms; Sleep
Link ID: 14880 - Posted: 01.17.2011

Those first few puffs on a cigarette can within minutes cause genetic damage linked to cancer, US scientists said in a study released Saturday. In fact, researchers said the "effect is so fast that it's equivalent to injecting the substance directly into the bloodstream," in findings described as a "stark warning" to those who smoke. The study is the first on humans to track how substances in tobacco cause DNA damage, and appears in the peer-reviewed journal Chemical Research in Toxicology, issued by the American Chemical Society. Using 12 volunteer smokers, scientists tracked pollutants called PAHs, or polycyclic aromatic hydrocarbons, that are carried in tobacco smoke and can also be found in coal-burning plants and in charred barbecue food. They followed one particular type -- phenanthrene, which is found in cigarette smoke -- through the blood and saw it form a toxic substance that is known to "trash DNA, causing mutations that can cause cancer," the study said. "The smokers developed maximum levels of the substance in a time frame that surprised even the researchers: just 15-30 minutes after the volunteers finished smoking," the study said. "These results are significant because PAH diol epoxides react readily with DNA, induce mutations, and are considered to be ultimate carcinogens of multiple PAH in cigarette smoke," the study said. © 2011 Discovery Communications, LLC.

Keyword: Drug Abuse; Genes & Behavior
Link ID: 14879 - Posted: 01.17.2011

FEELING happy? Down in the dumps? Or been behaving strangely lately? Besides the obvious reasons, whether or not you are happy or sad, or prone to depression or other mental illnesses, could be a consequence of an infection - or even down to the diseases that you didn't catch during childhood. "It used to be thought that the immune system and the nervous system were worlds apart," says John Bienenstock of McMaster University in Hamilton, Canada. Now it seems the immune system, and infections that stimulate it, can influence our moods, memory and ability to learn. Some strange behaviours, such as obsessive compulsive disorder, may be triggered by infections, and the immune system may even shape our basic personalities, such as how anxious or impulsive we are. The good news is that understanding these links between the brain and immune system could lead to new ways of treating all kinds of disorders, from depression to Tourette's syndrome. This is a massive shift in thinking. Not so long ago, the blood-brain barrier was thought to isolate the brain from the immune system. The cells that make up the walls of blood capillaries are joined together more tightly in the brain than elsewhere in the body, preventing proteins and cells getting into the brain. Now, though, it is becoming clear that antibodies, signalling molecules and even immune cells often get through, sometimes with radical effects. In fact, immune cells do not even need to reach the brain to influence it. Here we look at some of the effects they can have.

Keyword: Emotions; Neuroimmunology
Link ID: 14878 - Posted: 01.17.2011

Jennifer Couzin-Frankel In the fall of 2008, Stephen Kingsmore, a longtime gene hunter, was approached by two biotech entrepreneurs. One of them, Craig Benson, had just learned that his 5-year-old daughter had juvenile Batten disease, a rare, fatal, inherited, neurological disorder. The pair had a question for Kingsmore: Could he develop a cheap, reliable genetic test for Batten and other equally horrible diseases, available to all parents to prevent the conception or birth of affected children? Their goal was simple: Do everything possible to eradicate these diseases, because, knowing now which genes cause them, we can. At the time this kind of screening, called carrier testing, was relatively uncommon. Both parents need to carry the same mutated gene for their child to develop a disease like Batten, and many of these recessive diseases are vanishingly rare. The number of affected children born each year can be in the single digits. Given that, it hasn't made fiscal sense to offer tests for dozens of diseases to everyone when so few couples will be carriers of any given one. In communities in which certain mutated genes pop up more often, such as Ashkenazi Jews, carrier testing has been common for years and has drastically reduced the number of babies born with diseases like Tay-Sachs. But DNA sequencing technology was moving fast and costs were dropping. What the two men proposed might now be doable, Kingsmore thought. He took on the project. © 2011 American Association for the Advancement of Science.

Keyword: Genes & Behavior; Development of the Brain
Link ID: 14877 - Posted: 01.17.2011

By Laura Sanders Satirist Stephen Colbert envisions his “Colbert Nation” mentally marching in lockstep with his special brand of patriotism. But scientists have done him one better, by creating tiny worm-bots completely under their control. Rather than comedic persuasion, these scientists are using a dot of laser light. With it they can make a worm turn left, freeze or lay an egg. The researchers report their work online January 16 in Nature Methods. The new system, named CoLBeRT for “Controlling Locomotion and Behavior in Real Time,” doesn’t just create a mindless zombie-worm, though. It gives scientists the ability to pick apart complicated behaviors on a cell-by-cell basis. “This system is really remarkable,” says biological physicist William Ryu of the University of Toronto, who was not involved in the research. “It’s a very important advance in pursuit of the goal of understanding behavior.” Transparent and small, the nematode C. elegans is particularly amenable to light-based mind control. Another benefit of the worm is that researchers know the precise location of all 302 of its nerve cells. But until now, there wasn’t a good way to study each cell by itself, especially in a wriggling animal. “This tool allows us to go in and poke and prod at those neurons in an animal as it’s moving, and see exactly what each neuron does,” says study coauthor Andrew Leifer of Harvard University. © Society for Science & the Public 2000 - 2011

Keyword: Miscellaneous
Link ID: 14876 - Posted: 01.17.2011

Greg Miller Everyone knows what it's like to be lonely. It often happens during life's transitions: when a student leaves home for college, when an unmarried businessman takes a job in a new city, or when an elderly woman outlives her husband and friends. Bouts of loneliness are a melancholy fact of human existence. But when loneliness becomes a chronic condition, the impact can be far more serious, says John Cacioppo, a social psychologist at the University of Chicago in Illinois. Cacioppo studies the biological effects of loneliness, and in a steady stream of recent papers, he and collaborators have identified several potentially unhealthy changes in the cardiovascular, immune, and nervous systems of chronically lonely people. Their findings could help explain why epidemiological studies have often found that socially isolated people have shorter life spans and increased risk of a host of health problems, including infections, heart disease, and depression. Their work also adds a new wrinkle, suggesting that it's the subjective experience of loneliness that's harmful, not the actual number of social contacts a person has. “Loneliness isn't at all what people thought it was, and it's a lot more important than people thought it was,” Cacioppo says. Colleagues credit him with building an impressive network of collaborations with researchers in other disciplines to pioneer a new science of loneliness. “He's placed it on the scientific map,” says one collaborator, Dorret Boomsma, a behavioral geneticist at Vrije Universiteit Amsterdam in the Netherlands. “He's doing very creative work,” says Martha Farah, a cognitive neuroscientist at the University of Pennsylvania. “He's created a new way of thinking about the biology of interpersonal relationships.” © 2011 American Association for the Advancement of Science.

Keyword: Stress; Emotions
Link ID: 14875 - Posted: 01.15.2011

By Laura Beil Mice aren’t known for their skill with complicated memory tricks, but they can usually recall their last meal. Once they happen upon food in a laboratory maze, they are pretty good at remembering the location from one trial to the next. In one recent study, though, half the mice got too confused to find their snacks. All the mice in two groups tested could remember the location of a new reward stashed in a vastly different place from an earlier one. But one group had trouble when the payoff lay just slightly off from a previous spot. Those mice had a good excuse, though: Their brains were incapable of creating new nerve cells, or neurons, in a region important for memory. In the late ’90s, scientists stunned the research world with the discovery that human adults aren’t stuck with only the neurons they’re born with — an idea long entrenched in neuroscience dogma. In fact, adult brains are getting fresh batches of nerve cells every day. Since that revelation, researchers have been trying to answer a nagging question: What are the new neurons good for? While it’s now widely accepted that new cells are appearing in a part of the brain that codes and packages memories, the precise function of these newborn brain cells remains unclear. Many researchers are now convinced that new cells are indeed vital for recording memories, but not all forms of memory — just those that tend to get jumbled with other similar ones (such as what you had for lunch yesterday or where you parked your car). © Society for Science & the Public 2000 - 2011

Keyword: Learning & Memory; Neurogenesis
Link ID: 14874 - Posted: 01.15.2011

by Debora MacKenzie You catch flu by inhaling germs – now it seems you can catch prion diseases that way too. Prions are misshapen proteins that cause brain degeneration in conditions such as mad cow disease and scrapie in animals, and Creutzfeldt–Jakob disease in humans. They can get into you if you eat infected meat or receive infected blood, but it was thought they couldn't spread through air. Now Adriano Aguzzi of the Swiss Federal Institute of Technology in Zurich reports that mice exposed for 10 minutes to aerosols containing as little as 2.5 per cent brain tissue from mice with scrapie all developed the disease within months. The prions didn't need processing by the immune system first, as some other research has suggested, but entered the brain directly through nasal nerves. "We were amazed at how efficiently they spread," says Aguzzi. He warns that this doesn't mean animals or people with prion diseases actually transmit them through the air: there have been no unexplained cases of disease transmission which suggested this. But workers in mills that process potentially infected carcasses may need more respiratory protection. Labs that test for prions routinely make 10 per cent suspensions of brain tissue, and any handling – pipetting, for example – creates aerosols. Prion labs are not required to use safety equipment that protects workers from aerosols. Aguzzi, who tested his aerosols at the highest level of protection, thinks those labs may now need to rethink safety measures. Journal reference: PLoS Pathogens, DOI: 10.1371/journal.ppat.1001257 © Copyright Reed Business Information Ltd.

Keyword: Prions
Link ID: 14873 - Posted: 01.15.2011

by Wendy Zukerman Female crickets prefer the serenades of younger males. The findings defy a well-established theory that females prefer older males because their longevity shows they have good genes. This idea was largely unproven, says Luke Verburgt of the University of Pretoria, South Africa. And once he put it to the test using field crickets (Gryllus bimaculatus), he found it isn't accurate. Instead, female crickets prefer the higher-pitched and louder songs sung by younger males, he says. Verburgt and colleagues recorded the mating songs of the same 25 male field crickets when they were young (10 to 12 days old) and older (48 to 50 days old). He analysed the songs' traits, including the number of single sounds – or syllables – per song, the length of the syllables and the song's frequency. Youthful vigour Nearly all the traits changed with age. For instance, as crickets became older they sang lower, more staccato songs. The young male song was louder and on average 80 hertz higher than the older male songs. Verburgt believes the muscles needed to produce songs become weaker with age, and so older crickets may not be able to sustain the force required to produce longer syllables. © Copyright Reed Business Information Ltd.

Keyword: Sexual Behavior; Evolution
Link ID: 14872 - Posted: 01.15.2011

By JOSHUA SPARROW, M.D. Several readers wrote about their children with autism spectrum disorders and their children’s difficulties both with handling the sensory overload that comes with this time of year and with understanding the deeper meanings of the holidays. The challenges of children with autism spectrum disorders and the behaviors that result can be baffling for those who have had little experience with them. It can likewise be baffling for those who are familiar with autism, including parents and other family members, as well as the children themselves. Most of these behaviors arise from differences in the ways that these children experience, understand and interact with the world. Some children with autism spectrum disorders do not speak at all, while others develop the ability to speak later than typically developing children. Most find it hard to understand the social and emotional meanings of language and nonverbal behavior, including words about emotions, or facial expressions and tones of voice that convey emotions. They also have a harder time understanding their own feelings, and those of others, than children without autism. However, these differences in understanding and expressing their feelings often lead others to underestimate their potential for empathy, compassion and other emotions. Still, abstract ideas and symbols — like Christmas trees, a baby in a manger and everlasting lights — are also often difficult for them to comprehend. Many children with autism spectrum disorders are easily overwhelmed by sights, sounds and touch, and even by smells and tastes. To protect themselves, these children shut out sensory information by withdrawing or absorbing themselves in repetitive behaviors or idiosyncratic interests, which can interfere with learning about their surroundings and connecting with the people who care most about them, including their parents. © 2011 The New York Times Company

Keyword: Autism
Link ID: 14871 - Posted: 01.15.2011

The inner ear helps you hear, and keep your balance, but a new study in mice suggests that it may do much more, helping with breathing. The upcoming finding in the journal Neuroscience, may as well have implications for Sudden Infant Death Syndrome (SIDS) in infants, suggests the study's senior author, Daniel Rubens of Seattle Children's Hospital. "We have basically shown that inner ear damage leads to a loss of response to increased carbon dioxide levels," says Rubens. Rubens led a a 2007 study in the Human Development journal that found higher odds of SIDS in infants who scored poorly on early hearing tests. The new study examines examines a possible involvement of the inner ear in the mechanism of SIDS. SIDS kills about 2,200 infants nationwide yearly, according to the National Center for Health Statistics. The researchers compared 40 infant mice with inner ear damage from 'gentamicin' antibiotic injections to 20 other control mice (10 with salt water injections but not antibiotic, 5 with antibiotic administered system-wide but not into the ear, and 5 exposed only to the anesthetic without injections). The gentamicin antibiotic damages specialized hair cells in the inner ear that detect changes in both balance and hearing. Carbon dioxide levels produced in the body drives respiration in humans and other mammals. The team led by authors Rubens and Travis Allen, also of Seattle Children's Hospital, compared the response of the experiment's mice to increases in carbon dioxide levels while asleep. Within 10 seconds, the undamaged control mice's breathing increased in response to the increased carbon dioxide levels. In contrast the inner-ear damaged mice showed little, if any, response. © 2011 USA TODAY,

Keyword: Sleep; Hearing
Link ID: 14870 - Posted: 01.15.2011