By Steve Connor, Science Editor People are more likely to become lovers if their genes share little in common, according to a study that demonstrates a possible biological mechanism controlling the sexual attraction between men and women. Heterosexual men and women with dissimilar genes are more likely to get married than people with a similar genetic heritage. The findings indicate that certain genes control some of the subconscious desires behind the choice of one partner over another, as a way of preventing inbreeding and boosting a child's immune defences. Researchers studied the genes of 90 married couples and found that their DNA in a key region of their chromosomes was significantly different compared with the same stretch of DNA in 152 couples chosen at random from the population and who were neither married nor having sexual relations with one another. The genes, called the major histocompatibility complex (MHC), are part of the immune system. This is the first rsearch of its kind showing that they may play a significant role in whether or not couples are likely to get married. If the MHC genes played no role in the choice of a mate, then the scientists would expect to find similar differences between both sets of couples – the married and the unmarried. However, the statistically significant difference suggests that the dissimilar MHC genes influenced whether men and women become attracted to one another. ©independent.co.uk

Keyword: Sexual Behavior; Genes & Behavior
Link ID: 12876 - Posted: 06.24.2010

By Susan Milius “You’ve got to suffer if you want to sing the blues” may apply to mockingbirds too. In the Mimidae family, of mockingbirds and thrashers, the species with the more elaborate male courtship songs tend to be those living in the more challenging climates, says Carlos Botero of the National Evolutionary Synthesis Center in Durham, N.C. Virtuoso birdsong, Botero explains, means precision in repeated elements, abundant variety in tweets and trills plus dead-on mimicry of other sounds, whether from neighboring bird species or car alarms. Mockingbird species that excel in such performance tend to breed in zones of hard-to-predict and highly variable temperature and precipitation, Botero and his colleagues report online May 21 in Current Biology. Like other songbirds, mockingbirds and their relatives have to learn the vital singing skills for wooing and warring. If climate has something to do with brain evolution and learning, as some scientists have long hypothesized, then bird music may reveal the effects, the researchers propose. “Nobody has looked at climate and bird song before,” Botero says. This proposed link is important, says Daniel Sol of the Autonomous University of Barcelona in Spain, “because it suggests that sexual selection can also be affected by climatic variability.” That influence, he adds, “is key to understand the possible impact of climate change on biodiversity.” © Society for Science & the Public 2000 - 2009

Keyword: Sexual Behavior; Evolution
Link ID: 12875 - Posted: 06.24.2010

The Alzheimer's research community is buzzing about a theory suggesting that a close relative of the beta-amyloid protein, and not necessarily beta-amyloid itself — the long-standing suspect — may be a major culprit in the disease. The theory holds that an amyloid-related mechanism that prunes neuronal connections in the brain in the fast-growth phase of early life may be triggered by ageing-related processes in later life to cause the neuronal withering of Alzheimer's disease (A. Nikolaev et al. Nature 457, 981–989; 2009). "We have yet to get a disease-modifying drug that works. So we're missing something, and maybe this is one of the missing pieces," says Donna Wilcock, a neurologist at Duke University in Durham, North Carolina. "I think people are bored of the amyloid hypothesis and would just love to have something else to follow up," adds John Hardy, a neurologist at University College London. Insoluble clumps of the beta-amyloid peptide appear in the brains of patients with Alzheimer's, and mutations in amyloid's precursor protein (APP) have been linked to rare, familial forms of the disease. But how amyloid contributes to the damage of Alzheimer's is not clear, and several anti-amyloid drugs have failed in phase III clinical trials (see Nature 456, 161–164; 2008). Some scientists are unsure that any form of beta-amyloid contributes to much of the neuronal destruction. © 2009 Nature Publishing Group,

Keyword: Alzheimers; Development of the Brain
Link ID: 12874 - Posted: 06.24.2010

by Ewen Callaway A newly identified gene called happyhour makes fruit flies sensitive to booze. Drugs that mimic the effects of the gene may offer a new treatment against alcohol abuse, researchers say. "People who are very sensitive to alcohol tend to drink less – that's the person who gets drunk on one glass of wine," says Robert Swift, a psychiatrist at Brown University in Providence, Rhode Island, who was not involved in the new study. "The person who can drink everybody under the table – that's that person who is more likely to become an alcoholic," he adds. When they drink, laboratory fruit flies aren't so different from pub-crawlers on a Friday night. "They go through a phase of hyperactivity and they gradually become uncoordinated; they stop moving and they fall over; and eventually they are unable to right themselves," says Ulrike Heberlein, a molecular biologist at the University of California, San Francisco, who led the new study. Bar flies Heberlein and colleague Ammon Corl hunted for mutant fruit flies able to keep the party going and not pass out. Two strains of flies fit this description, and both carried mutations in a gene that Heberlein's team dubbed happyhour. © Copyright Reed Business Information Ltd

Keyword: Drug Abuse; Genes & Behavior
Link ID: 12873 - Posted: 06.24.2010

By Andrew Holtz PORTLAND, OREGON -- It is easy to understand how explosions involving shrapnel – such as those caused by improvised explosive devices in Iraq – could cause brain damage. But what about such injuries that seem to be caused by blasts themselves, rather than from being thrown or hit by shrapnel? Researchers have a few ideas, but one scientist has used some of the world’s most powerful computers at the Lawrence Livermore National Laboratory in California to get a better answer. Willy Moss and colleague Michael King used available data on blast waves from explosions and the physical properties of the human skull, brain and cerebrospinal fluid to craft a three-dimensional simulation of a soldier standing less than 15 feet from an explosion of 5 lbs. of C4. (See image to the right.) “It sweeps over. There’s lots of oscillation. The skull is ringing. It’s not pleasant,” Moss told the audience at the meeting of the Acoustical Society of America here. Moss says their simulations suggest that the intense pressures of such blasts flex the skull and ripple the brain. Pressures as little as one atmosphere over normal atmospheric pressure can do that kind of damage. They repeated the simulation to include helmets, first using data from an older style that uses webbing to create space around a soldier’s head. (See video below.) “What you see is the blast sweeps under the helmet. It acts as a wind scoop; it focuses the blast. The blast pressure is bigger between your head and the helmet than if you weren’t wearing the helmet at all.” © 1996-2009 Scientific American Inc.

Keyword: Brain Injury/Concussion
Link ID: 12872 - Posted: 06.24.2010

By BENEDICT CAREY LAGUNA WOODS, Calif. — The ladies in the card room are playing bridge, and at their age the game is no hobby. It is a way of life, a daily comfort and challenge, the last communal campfire before all goes dark. For all that scientists have studied it, the brain remains the most complex and mysterious human organ — and, now, the focus of billions of dollars’ worth of research to penetrate its secrets. This bridge game is not for the timid. Norma Koskoff, left, Ruth Cummins and Georgia Scott expect the best from every player. If someone’s skills start slipping, it is time to find a new table. “We play for blood,” says Ruth Cummins, 92, before taking a sip of Red Bull at a recent game. “It’s what keeps us going,” adds Georgia Scott, 99. “It’s where our closest friends are.” In recent years scientists have become intensely interested in what could be called a super memory club — the fewer than one in 200 of us who, like Ms. Scott and Ms. Cummins, have lived past 90 without a trace of dementia. It is a group that, for the first time, is large enough to provide a glimpse into the lucid brain at the furthest reach of human life, and to help researchers tease apart what, exactly, is essential in preserving mental sharpness to the end. Copyright 2009 The New York Times Company

Keyword: Learning & Memory; Alzheimers
Link ID: 12871 - Posted: 06.24.2010

Scientists say they have located the brain areas that may determine how sociable a person is. Warm, sentimental people tend to have more brain tissue in the outer strip of the brain just above the eyes and in a structure deep in the brain's centre. These are the same zones that allow us to enjoy chocolate and sex, the Cambridge University experts report in the European Journal of Neuroscience. The work suggests that some people may get a similar buzz from being sociable. It could also lead to new insights into psychiatric disorders where difficulties in social interaction are prominent, such as autism or schizophrenia. For some people, socializing is an intrinsic reward, just like chocolate or cannabis Professor Simon Baron Cohen, of the Autism Research Centre in Cambridge The brain scan study was carried out on 41 healthy male volunteers. The men who scored higher on questionnaire-based ratings of emotional warmth and sociability had more grey matter in two brain areas - the orbitofrontal cortex and ventral striatum. The researchers say it is not clear whether the men were born with these brain differences or whether the brain regions in question grew in response to personal experiences. Experts already know that the striatum becomes activated by receiving compliments and the orbitofrontal cortex is activated by attractive faces and smiling. Lead researcher Dr Graham Murray said: "Sociability and emotional warmth are very complex features of our personality. This research helps us understand at a biological level why people differ in the degrees to which we express those traits. It's interesting that the degree to which we find social interaction rewarding relates to the structure of our brains in regions that are important for very simple biological drives such as food, sweet liquids and sex." (C)BBC

Keyword: Emotions
Link ID: 12870 - Posted: 05.23.2009

Scientists have shown there may be biochemical reasons - quite apart from the mental trauma of diagnosis - why cancer patients can become depressed. A University of Chicago team found tumours produce chemicals which can produce negative mood swings. They say the findings shed new light on why depression is such a risk for many cancer patients. The study, carried out on rats, features in Proceedings of the National Academy of Sciences. It has long been known that cancer is associated with depression. Experts thought this was likely to be either a result of the trauma of diagnosis, or possibly a side effect of chemotherapy treatment. The Chicago study suggests a third possibility. The researchers found that substances associated with depression are produced in increased quantities by tumours, and then are transmitted to the brain where they impact on the hippocampus - the area which regulates emotion. In addition, chemical pathways which normally put a brake on the impact of these depression-causing substances appear to be disrupted when a tumour develops. The researchers carried out tests on about 100 rats, some of which had cancer, to determine their emotional state. They found animals with tumours were less motivated to try to escape when submitted to a swimming test - a condition similar to depression in humans. Rats with tumours were also less eager to drink sugar water, a substance that usually attracts the appetites of healthy rats. Further tests revealed that the rats with tumours had increased levels of cytokines in their blood and in the hippocampus when compared with healthy rats. Cytokines are produced by the immune system, and an increase in cytokines has been linked to depression. (C)BBC

Keyword: Depression
Link ID: 12869 - Posted: 05.19.2009

By CARL ZIMMER The Komodo dragon is already a terrifying beast. Measuring up to 10 feet long, it is the world’s largest lizard. It delivers a devastating bite with its long, serrated teeth, attacking prey as big as water buffaloes. But in a provocative paper to be published this week, an international team of scientists argues that the Komodo dragon is even more impressive. They claim that the lizards use a potent venom to bring down their victims. Other biologists have greeted the notion of giant venomous lizards with mixed reactions. Some think the scientists have made a compelling case, while others say the evidence is thin. Biologists have long been intrigued by the success Komodo dragons have at killing big prey. They use an unusual strategy to hunt, lying in ambush and then suddenly delivering a single deep bite, often to the leg or the belly. Sometimes the victim immediately falls, and the lizards can finish it off. But sometimes a bitten animal escapes. Biologists have noted that the lizard’s victims may collapse later, becoming still and quiet, and even die. For decades, many scientists have speculated that the dragons infected their victims with deadly bacteria that lived in the bits of carrion stuck in their teeth. Yet others have always been skeptical of the bacteria hypothesis. “Your average lion has a much dirtier bite,” said Bryan Fry, a biologist at the University of Melbourne. “It’s complete voodoo.” Copyright 2009 The New York Times Company

Keyword: Neurotoxins
Link ID: 12868 - Posted: 06.24.2010

By Jackie Grom Christine Stracey remembers the first time a mockingbird dive-bombed her head. Since 2005, the graduate student at the University of Florida, Gainesville, has been invading the birds' nests in her neighborhood, counting eggs and banding chicks for a research project. Over time, she noticed that the birds were getting aggressive with her: They would squawk and swoop toward her as soon as they saw her coming. The mockingbirds seemed to have it out for Stracey in particular; they ignored passersby and even gardeners working right beneath their nests. "By the end of the summer, I was absolutely convinced that the birds knew me and did not like me!" she says. The idea that birds can recognize individual humans isn't new. Any parrot owner will tell you that Polly knows the difference between the owner and a stranger. And scientists have shown that crows can identify people by sight: In one unpublished experiment, the birds scolded researchers wearing caveman masks who had caught and banded them months earlier, but they ignored "neutral" figures wearing Dick Cheney masks. Still, no one had actually published work on the ability of birds to recognize people in the wild, and mockingbirds aren't considered to be as intelligent as parrots or crows. So Stracey persuaded her adviser, ecologist Doug Levey, to design an experiment to see if mockingbirds could really recognize individual people. First, Levey, Stracey, and colleagues located a brooding mockingbird on campus. Then they asked one volunteer to stand near the nest for 30 seconds and touch it for half of that time on four consecutive days while the mother mockingbird was present. With each visit, the bird grew more agitated. At first, the mother bird waited until the person came close and then flew to a nearby bush to shout out alarms calls, a behavior called flushing that birds do to distract predators in the wild. But by day four, mom was up and out of her nest when the volunteer was almost 14 meters away--and she or her mate dive-bombed the volunteer's head. © 2009 American Association for the Advancement of Science.

Keyword: Intelligence; Evolution
Link ID: 12867 - Posted: 06.24.2010

by Chris Mooney Vaccines do not cause autism. That was the ruling in each of three critical test cases handed down on February 12 by the U.S. Court of Federal Claims in Washington, D.C. After a decade of speculation, argument, and analysis—often filled with vitriol on both sides—the court specifically denied any link between the combination of the MMR vaccine and vaccines with thimerosal (a mercury-based preservative) and the spectrum of disorders associated with autism. But these rulings, though seemingly definitive, have done little to quell the angry debate, which has severe implications for American public health. The idea that there is something wrong with our vaccines—that they have poisoned a generation of kids, driving an “epidemic” of autism—continues to be everywhere: on cable news, in celebrity magazines, on blogs, and in health news stories. It has had a particularly strong life on the Internet, including the heavily trafficked Huffington Post, and in pop culture, where it is supported by actors including Charlie Sheen and Jim Carrey, former Playboy playmate Jenny McCarthy, and numerous others. Despite repeated rejection by the scientific community, it has spawned a movement, led to thousands of legal claims, and even triggered occasional harassment and threats against scientists whose research appears to discredit it. You can see where the emotion and sentiment come from. Autism can be a terrible condition, devastating to families. It can leave parents not only aggrieved but desperate to find any cure, any salvation. Medical services and behavioral therapy for severely autistic children can cost more than $100,000 a year, and these children often exhibit extremely difficult behavior. Moreover, the incidence of autism is apparently rising rapidly. Today one in every 150 children has been diagnosed on the autism spectrum; 20 years ago that statistic was one in 10,000. “Put yourself in the shoes of these parents,” says journalist David Kirby, whose best-selling 2005 book, Evidence of Harm, dramatized the vaccine-autism movement. “They have perfectly normal kids who are walking and happy and everything—and then they regress.” The irony is that vaccine skepticism—not the vaccines themselves—is now looking like the true public-health threat. (C) Discover

Keyword: Autism
Link ID: 12866 - Posted: 06.24.2010

by Carl Zimmer Four decades ago, an MIT neuroscientist named Jerry Lettvin had a sudden inspiration about how our brains make sense of the world. What if each of us had a special set of neurons in our head whose only job was to recognize a particular person, place, or thing? It was a strange idea, but given what Lettvin knew about the brain, it was plausible. To describe his idea to his students, he made up a story [pdf]. The story was about Alexander Portnoy, the protagonist of Philip Roth’s novel Portnoy’s Complaint, which had just been published. The novel is a long monologue delivered by Portnoy as he lies on the couch of his psychoanalyst. In Lettvin’s version, Portnoy instead decided to go to a neurosurgeon named Akakhi Akakhievitch. Dr. Akakhievitch had discovered 18,000 neurons in the human brain that respond uniquely to a person’s mother. Since much of Portnoy’s misery was caused by thoughts of his overbearing mom, Dr. Akakhievitch opened up his brain and removed all those mother cells. After the operation, Dr. Akakhi­evitch tried a test. “You remember the blintzes you loved to eat every Thursday night?” he asked. “They were wonderful,” Portnoy replied. “So who cooked them?” Portnoy stared at him blankly. Based on this great success, Lettvin told his students, Dr. Akakhi­evitch then extended his search to grandmother cells. (C) Discover

Keyword: Vision
Link ID: 12865 - Posted: 06.24.2010

By ANNIE CORREAL Luke McCarthy said he heard every word. A young man on a noisy street told a story about parking his car next to a construction site, where it was rolled over by a crane. “My car’s been flattened by this 44,000-pound machine,” Mr. McCarthy heard the man say. “It’s been run over like it was, you know, something in a monster truck rally.” Mr. McCarthy, 68, was not outside eavesdropping. He was sitting on Wednesday in a small room at the Center for Hearing and Communication, on the sixth floor of a building in Lower Manhattan, watching a video with an audiologist. “Was that hard?” asked the audiologist, Ellen Lafargue, pausing the video. “No, but I had to pay attention,” Mr. McCarthy said. Mr. McCarthy is deaf in his left ear and uses a hearing aid in his right ear. He was one of the first people to try a new audiovisual hearing test tailor-made for a city that by all accounts never shuts up. Instead of using beeps, tones and word lists — the more typical way to determine how well a new hearing aid works — the test conducted at the center uses sounds that might be heard in New York: cellphone chats, office discussions, the rumble of Midtown traffic. Copyright 2009 The New York Times Company

Keyword: Hearing
Link ID: 12864 - Posted: 06.24.2010

Keeping the brain active by working later in life may be an effective way to ward off Alzheimer's disease, research suggests. Researchers analysed data from 1,320 dementia patients, including 382 men. They found that for the men, continuing to work late in life helped keep the brain sharp enough to delay dementia taking hold. The study was carried out by the Institute of Psychiatry at King's College London. It features in the International Journal of Geriatric Psychiatry. Around 700,000 people in the UK currently have dementia and experts have estimated that by 2051, the number could stand at 1.7m. It is estimated that the condition already costs the UK economy £17bn a year. Dementia is caused by the mass loss of cells in the brain, and experts believe one way to guard against it is to build up as many connections between cells as possible by being mentally active throughout life. This is known as a "cognitive reserve". There is evidence to suggest a good education is associated with a reduced dementia risk. And the latest study suggests there can also be a positive effect of mental stimulation continued into our later years. Those people who retired late developed Alzheimer's at a later stage than those who opted not to work on. Each additional year of employment was associated with around a six week later age of onset. Researcher Dr John Powell said: "The possibility that a person's cognitive reserve could still be modified later in life adds weight to the "use it or lose it" concept where keeping active later in life has important health benefits, including reducing dementia risk." The researchers also admit that the nature of retirement is changing, and that for some people it may now be as intellectually stimulating as work. (C)BBC

Keyword: Alzheimers
Link ID: 12863 - Posted: 05.19.2009

A common heart disorder has been linked to a raised risk of Alzheimer's disease by US researchers. Atrial fibrillation causes the heart to beat chaotically, increasing the risk of blood clots and, if the condition is left untreated, stroke. It has previously been linked to some types of dementia - but not Alzheimer's, the most common form. The study, by Intermountain Medical Center in Utah, was based on more than 37,000 patients. The study found atrial fibrillation patients under the age of 70 had a 187% greater risk of all types of dementia compared with the general population. But their specific risk of Alzheimer's disease was also up - by 130%. However, the overall risk of Alzheimer's for all patients remained low. Lead researcher Dr Jared Bunch said: "Previous studies have shown that patients with atrial fibrillation are at higher risk for some types of dementia, including vascular dementia. "But to our knowledge, this is the first large-population study to clearly show that having atrial fibrillation puts patients at greater risk for developing Alzheimer's disease." Alzheimer's, which accounts for up to 80% of all dementia cases, is known to be linked to age and genetics. It has long been suspected that poor heart health may also play a role. The researchers said more research was needed to explain why atrial fibrillation may raise the risk of Alzheimer's. They put forward several theories for a possible link. They suspect atrial fibrillation damages the small blood vessels, potentially reducing blood flow to the brain. Alternatively, the condition is linked to tiny micro-strokes, the damage from which may accumulate over time, making Alzheimer's more likely. (C)BBC

Keyword: Alzheimers
Link ID: 12862 - Posted: 05.16.2009

By PETER JARET Like bum knees and crow’s feet, cataracts are the price we pay for getting older. Cataracts form when the normally transparent lens of the eye turns cloudy. At least three out of five people over age 60 will eventually develop them. Today, thanks to a steady march of advances, cataract replacement surgery often gives people better vision than they’ve had in years. Progress in the field has been nothing short of astonishing, experts say, starting with the development of artificial lenses about 30 years ago. “In the early days, all we could do was remove the cataractous lens,” said Dr. Peter R. Egbert, director of the Cataract Service at Stanford University. “Patients ended up with no lens in their eye to focus and had to wear very thick glasses to see. Nobody was happy with the results.” Patients can now choose from a wide range of artificial lenses. The most common are monofocal lenses, which focus vision at a single distance, the way a pair of standard glasses does. Before surgery, ophthalmologists test the eyes to choose the best prescription for the artificial lens, based on whether patients are nearsighted or farsighted or have normal vision. Multifocal lenses, designed to focus both up close and at a distance, are a newer option. They are particularly appealing because by the time people develop cataracts, usually starting in their 60s, most suffer from presbyopia and require reading glasses. Presbyopia occurs when the body’s natural lens stiffens with age and eye muscles can no longer focus it for close vision. Copyright 2009 The New York Times Company

Keyword: Vision
Link ID: 12861 - Posted: 06.24.2010

Getting a good night’s rest is essential for good health, but people with sleep apnea aren’t able to succumb to slumber. Obstructive sleep apnea causes episodes of stopped breathing during sleep, and the result is a fragmented, restless sleep that leaves sufferers exhausted and drowsy during the day. Sleep apnea is common, affecting more than 12 million Americans. But most people with the problem haven’t been diagnosed. The problem is more common in men, and associated with being overweight and over 40. Untreated sleep apnea has been linked with high blood pressure, memory problems, weight gain, headaches and car crashes. To learn more about life with sleep apnea, listen to the latest installment of the Patient Voices series from New York Times Web producer Karen Barrow. You’ll meet Ursula Forhan, 54, of Chicago, who says constant tiredness is the worst part of having sleep apnea. “It’s a grinding kind of fatigue,” she says. “It’s a fatigue that makes you ration what you’ll do….You don’t have enough energy for everything.” And you’ll meet Eric Ramme, 54, of Manhattan, who thought his sleep problems were linked to his pillow, mattress or even the traffic outside his window. After his diagnosis, he ultimately underwent surgery to correct the problem. “When you have a good night’s sleep you attack your day,” he says. “You’re happier. So many things are related directly to the quality of sleep you have.” Copyright 2009 The New York Times Company

Keyword: Sleep
Link ID: 12860 - Posted: 06.24.2010

By Janet Raloff Testing for lead only in infants and toddlers may be a mistake, a new study suggests. Pediatricians routinely test very young children because this is the age when blood concentrations of the neurotoxic heavy metal tend to be highest. But older children can face significant lead exposures, and lead’s ability to lower IQ, the new study shows, is much greater for exposures in early school-age children than in toddlers. The study, which will appear in an upcoming Environmental Health Perspectives, also finds that the later childhood exposures correlate more strongly than earlier ones with an exaggerated risk of incurring future criminal arrests for violent behavior. The new data “get at a key concept in environmental health: that there may be some windows of vulnerability — stages of development — that are more vulnerable than others,” notes environmental epidemiologist Howard Hu of the University of Michigan in Ann Arbor. If school-age brains are more susceptible to lead toxicity than younger ones, “that’s important to know, from a public health perspective,” he says. Looking for lead in older children would be a first step in identifying families that need counseling on reducing sources of lead in and around the home. Richard Hornung and his colleagues at Cincinnati Children’s Hospital Medical Center analyzed data on lead levels and IQ from 462 children. About half of the data were collected from kids in Cincinnati during the early 1980s, the rest from kids in Rochester, N.Y., during the mid-1990s. © Society for Science & the Public 2000 - 2009

Keyword: Neurotoxins; Intelligence
Link ID: 12859 - Posted: 06.24.2010

by Helen Thomson If I was reading this sentence aloud, your brain would be able to interpret whether I was speaking in anger, joy, relief, or sadness. That's because emotions in speech leave distinct "signatures" in the brain of the listener. Now, for the first time, brain scans have now characterised those patterns. The finding could help determine where in the brain deficits in emotion processing occur in people with psychiatric disorders such as schizophrenia. Thomas Ethofer at the University Medical Center of Geneva, Switzerland, and colleagues identified spatial signatures of emotion in the primary auditory cortex (PAC) – an area of the temporal lobes at the side of the brain, which is responsible for the sensation of sound. This area is known to react more strongly to emotional vocalisations than to neutral speech, but because this increase in activity is similar for all emotions, scientists had been previously unable to separate one mood from another by using scans. To solve this problem, Ethofer scanned the brains of 22 subjects using functional magnetic resonance imaging (fMRI) while they listened to emotional speech, and combined this with a technique called multivariate pattern analysis (MVPA) – used to identify patterns in brain activation. © Copyright Reed Business Information Ltd

Keyword: Emotions
Link ID: 12858 - Posted: 06.24.2010

By Elsa Youngsteadt The year was 1970. Simon and Garfunkel topped the charts, floppy disks were brand-new, and California white-crowned sparrows (Zonotrichia leucophrys) sang fast machine-gun trills. Just a few decades later, the sparrows sing noticeably slower songs, and a new study reveals the reason. The birds' habitat has gotten scrubbier, and their melodies have evolved to better penetrate the thickets. Ecologists have argued for decades that habitat influences the evolution of bird song. Slow songs and low-pitched sounds transmit better through dense vegetation, whereas high notes carry farther in open environments. And overall, grassland birds do have faster, shriller songs than those from leafy surroundings have. But researchers discovered this by comparing modern populations or species from different habitats. They didn't know how long it would take a species' song to adapt to a new environment. Now they do, thanks to a collection of historical recordings of white-crowned sparrows. Evolutionary ecologist Elizabeth Derryberry, now of Louisiana State University Museum of Natural Science in Baton Rouge, knew that, beginning in the late 1960s, renowned ornithologist Luis Baptista had spent decades studying the birds' chattery, buzzy songs. But she couldn't find his tapes. Finally, in 2003, 3 years after Baptista's death, Derryberry tracked down the sparrow songs in the professor's old office at the California Academy of Sciences in San Francisco. Among the boxes and reprints, she uncovered the songs of 170 male sparrows from 15 locations on the West Coast. © 2009 American Association for the Advancement of Science

Keyword: Evolution; Language
Link ID: 12857 - Posted: 06.24.2010