by Ewen Callaway Sweet-toothed Brits have one less excuse for taking their morning tea with several spoons of sugar. They and other Europeans are among the most sugar-sensitive people in the world, a new genetic analysis concludes. The vast majority of people in the UK, France, Italy and Russia boast a tandem of genetic variations in a sugar-sensing gene that allows them to detect trace levels of sweetness. Around the world, populations that live at northern latitudes carry these genetic variations at far higher frequencies than tropical-living peoples, says Dennis Drayna, a geneticist at the National Institute on Deafness and Other Communication Disorders in Bethesda, Maryland. His team presented 144 Europeans, Asians and Africans with nine solutions containing varying amounts of table sugar – sucrose – in amounts varying from 0 to 4 per cent. "Four-per-cent sucrose is very sweet to everyone, and to me it's intensely sweet," Drayna says. "Imagine some cloyingly sweet desert." Volunteers arranged the solutions in order of their perceived sweetness numerous times, and from these, Drayna's team calculated a sucrose sensitivity score for each person. © Copyright Reed Business Information Ltd.

Keyword: Chemical Senses (Smell & Taste); Obesity
Link ID: 12994 - Posted: 06.24.2010

By Kelli Whitlock Burton Homing pigeons use landmarks to guide them safely home. But how do the birds track these familiar sites hundreds of meters below as they zip by at 65 kilometers per hour? Scientists are trying to answer that question with a new device that lets them record brain activity as pigeons fly. Exactly how pigeons find their way home is a mystery. While some studies suggest the birds rely on smells, the position of the sun, or Earth's magnetic field to navigate, scientists also know that pigeons use visual landmarks. To see how the pigeons' brains processed these sights, Alexei Vyssotski and colleagues at the University of Zurich in Switzerland developed the Neurologger2, a device that simultaneously tracks the birds' route while also recording brain activity as they fly over familiar sites. Neurologger2 weighs just 2 grams and uses an electroencephalogram to record brain activity. In a study published online this week in Current Biology, the scientists trained 26 pigeons to recognize a loft as their home base. Then, they implanted tiny electrodes on the birds' brains and connected them with Neurologger2. They outfitted the birds with global positioning system monitors and then released them from different points 10 to 30 kilometers away from the loft. Once the birds returned, the researchers removed the devices and compared the record of the birds' brain activity with their positions at the time. Vyssotski found that when the birds flew over landmarks, such as a familiar highway, high-frequency brain waves suddenly got more intense. © 2009 American Association for the Advancement of Science.

Keyword: Animal Migration; Brain imaging
Link ID: 12993 - Posted: 06.24.2010

By Charles Q. Choi For decades scientists have noted that mature humans physically resemble immature chimps—we, too, have small jaws, flat faces and sparse body hair. The retention of juvenile features, called neoteny in evolutionary biology, is especially apparent in domesticated animals—thanks to human preferences, many dog breeds have puppy features such as floppy ears, short snouts and large eyes. Now genetic evidence suggests that neoteny could help explain why humans are so radically different from chimpanzees, even though both species share most of the same genes and split apart only about six million years ago, a short time in evolutionary terms. In animals, neoteny comes about because of delays in development, points out molecular biologist Philipp Khaitovich of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. For instance, humans sexually mature roughly five years after chimps do, and our teeth erupt later. “Changes in the timing of development are some of the most powerful mechanisms evolution can use to remodel organisms, with very few molecular events required,” he explains. To look for genetic evidence that neoteny played a role in the evolution of Homo sapiens, Khaitovich and his colleagues compared the expression of 7,958 genes in the brains of 39 humans, 14 chimpanzees and nine rhesus monkeys. They collected samples from the dorsolateral prefrontal cortex—a region linked with memory that is relatively easy to identify in the primate brain. These tissues came from deceased individuals at several stages of life, from infancy to middle age, enabling the researchers to see how genetic activity changed over time in each species. © 1996-2009 Scientific American Inc.

Keyword: Evolution; Development of the Brain
Link ID: 12992 - Posted: 06.24.2010

By RONI CARYN RABIN Being overweight won’t kill you — it may even help you live longer. That’s the latest from a study that analyzed data on 11,326 Canadian adults, ages 25 and older, who were followed over a 12-year period. The report, published online last week in the journal Obesity, found that overall, people who were overweight but not obese — defined as a body mass index of 25 to 29.9 — were actually less likely to die than people of normal weight, defined as a B.M.I. of 18.5 to 24.9. By contrast, people who were underweight, with a B.M.I. under 18.5, were more likely to die than those of average weight. Their risk of dying was 73 percent higher than that of normal weight people, while the risk of dying for those who were overweight was 17 percent lower than for people of normal weight. The finding adds to a simmering scientific controversy over the optimal weight for adults. In 2007, scientists at the Centers for Disease Control and Prevention and the National Cancer Institute reported that overweight adults were less likely than normal weight adults to die from a variety of diseases, including infections and lung disease. “Overweight may not be the problem we thought it was,” said Dr. David H. Feeny, a senior investigator at Kaiser Permanente Center for Health Research in Portland, Ore., and one of the authors of the study. “Overweight was protective.” Copyright 2009 The New York Times Company

Keyword: Obesity
Link ID: 12991 - Posted: 06.24.2010

How can a hypnotist paralyze your hand just with words? By making a part of your brain butt in on the process that normally makes your hand move, a study says. So the brain region that's ready to move your hand ignores its usual inputs and listens to this interloper, which says, "Don't even bother," the research concluded. It's "a kind of reconnection between different brain regions," said Yann Cojan, a researcher at the University of Geneva in Switzerland. He's an author of the study in Thursday's issue of the journal Neuron. It used brain scans to show what happened when 12 volunteers tried to move a hand that had been paralyzed by hypnosis. Results showed the right motor cortex prepared itself as usual to tell the left hand to move. But the cortex appeared to be ignoring the parts of the brain it normally communicates with in controlling movement. Instead, it acted more in sync than usual with a different brain region called the precuneus. That was a surprise, Cojan said. The precuneus is involved in mental imagery and memory about oneself. Cojan suggests it was brimming with the metaphors the participants had heard from the hypnotist: Your hand is very heavy, it is stuck on the table, etc. So, he said, it might have been telling the motor cortex, "Oh, but your hand is too heavy, you can't move your hand." It's as if the motor cortex "is connected to the idea that it cannot move (the hand) and so ... it doesn't send the message to move," Cojan said. For the research, 12 participants had their brains scanned while doing a task that required them to push a button with one hand or the other. For some sessions, they were hypnotized and told their left hands were paralyzed. For other sessions, their mental status was normal. For comparison, six other participants simply pretended their left hands were paralyzed. © 2009 The Associated Press.

Keyword: Miscellaneous
Link ID: 12990 - Posted: 06.24.2010

Erin Allday, Chronicle Staff Writer -- Increasingly powerful antipsychotic drugs available on the market, and growing evidence that starting these medications early can help children with conditions like bipolar disorder, is putting doctors under more pressure than ever to diagnose and treat young people with mental illnesses. As a result, some doctors say, mental illness, especially bipolar disorder, has been overdiagnosed much the same way attention deficit hyperactivity disorder was in the 1980s. "ADHD was the diagnosis du jour in the '80s. Now it's become bipolar disorder," said Dr. Andrew Giammona, who heads the psychiatry department at Children's Hospital Oakland. "We're in a quick-fix society, and parents want to believe that if we had this treatment, we can get it fixed and move on." Before the 1990s, bipolar disorder was a rare diagnosis in children under age 19. By 1994, U.S. doctors were reporting about 25 cases per 100,000 young people, and by 2002 that number had jumped to 1,000 cases per 100,000, according to data from the National Center for Health Statistics. Medication was prescribed for about two-thirds of those patients, according to the National Institute of Mental Health. Antipsychotic medications are among the most popular made by pharmaceutical companies. Earlier this month, a U.S. Food and Drug Administration panel recommended approval of three antipsychotic drugs for use in treating schizophrenia and bipolar disorder in children and teens. The FDA will make a final decision on Geodon, Seroquel and Zyprexa in the coming weeks. © 2009 Hearst Communications Inc.

Keyword: Schizophrenia; Development of the Brain
Link ID: 12989 - Posted: 06.24.2010

Scientists at the University of Alberta have found there are significant differences in the way our brains function, depending on whether we are early risers or night owls. Using magnetic resonance imaging-guided brain stimulation, neuroscientists tested muscle torque and the excitability of pathways through the spinal cord and brain. "We found that the brains of morning people are more excitable in the morning and evening people are completely opposite," neurophysiology researcher David Collins said Tuesday. "The evening people ... it's almost a perfect storm of excitability in the central nervous system, where the brain is maximal in the evening and the spinal cord is maximal in the evening.... They generate the most force in the evenings," he said. David Collins, neurophysiology researcher at the University of Alberta (CBC)David Collins, neurophysiology researcher at the University of Alberta (CBC) "Morning people ... their brains are most excitable in the morning, but their spinal cords are most excitable in the evening," Collins said. The results may suggest that morning people are performing below their maximum possible level at all times of the day because of this, he said. © CBC 2009

Keyword: Biological Rhythms
Link ID: 12988 - Posted: 06.24.2010

P. Murali Doraiswamy is the head of biological psychiatry at Duke University and is a Senior Fellow at Duke’s Center for the Study of Aging. He’s also the co-author of The Alzheimer’s Action Plan, a guide for patients and family members struggling with the disease. Q: What do you think are the biggest public misconceptions of Alzheimer's disease? DORAISWAMY: The two biggest misconceptions are “It’s just aging” and “It’s untreatable, so we should just leave the person alone.” Both of these misconceptions are remnants of an outdated view that hinders families from getting the best diagnosis and best care. They were also one of the main reasons I wanted to write this book. Although old age is the single biggest risk for dementia, Alzheimer’s is not a normal part of aging. Just ask any family member who has cared for a loved one with Alzheimer’s and they will tell you how different the disease is from normal aging. Alzheimer’s can strike people as young as their forties; there are some half a million individuals in the United States with early-onset dementia. Recent research has pinpointed disruptions in specific memory networks in Alzheimer’s patients, such as those involving the posteromedial cortex and medial temporal lobe, that appear distinct from normal aging. The larger point is that while Alzheimer’s is still incurable it’s not untreatable. There are four FDA-approved medications available for treating Alzheimer symptoms and many others in clinical trials. Strategies to enhance general brain and mental wellbeing can also help people with Alzheimer’s. That’s why early detection is so important. © 1996-2009 Scientific American Inc

Keyword: Alzheimers
Link ID: 12987 - Posted: 06.24.2010

by Anil Ananthaswamy How blind and deaf people approach a cognitive test regarded as a milestone in human development has provided clues to how we deduce what others are thinking. Understanding another person's perspective, and realising that it can differ from our own, is known as theory of mind. It underpins empathy, communication and the ability to deceiveMovie Camera – all of which we take for granted. Although our theory of mind is more developed than it is in other animals, we don't acquire it until around age four, and how it develops is a mystery. You can test for theory of mind via the false-belief test, in which two children are shown playing. One puts a toy under the bed and leaves the room. The second then removes it and puts it in the toy box. On returning, where will the older child look for the toy? Those under the age of four choose the box, while older children correctly say under the bed. Where does this leap in understanding come from? According to one hypothesis, children gradually deduce that other people have internal experiences that are different from their own by observing the facial expressions and gestures of others over time. To test this idea, neuroscientist Rebecca Saxe at the Massachusetts Institute of Technology and colleagues scanned the brains of 10 congenitally blind adults as they answered questions about the beliefs of people described to them. © Copyright Reed Business Information Ltd

Keyword: Language; Autism
Link ID: 12986 - Posted: 06.24.2010

Lauren Neergaard, Associated Press -- Puzzling new research suggests women have a harder time than men looking at babies with facial birth defects. It's a surprise finding. Psychiatrists from the Harvard-affiliated McLean Hospital, who were studying perceptions of beauty, had expected women to spend more time than men cooing over pictures of extra-cute babies. Nope. Instead, the small study being published Wednesday raises more questions than it can answer. First the background: The McLean team already had studied men and women looking at photos of adults' faces on a computer screen. The participants rated facial beauty, and could do various keystrokes to watch the photos longer. A keystroke count showed men put three times more effort into watching beautiful women as women put into watching handsome men. Lead researcher Dr. Igor Elman wondered what else might motivate women. Enter the new baby study. This time 13 men and 14 women were shown 80 photos of babies, 30 of whom had abnormal facial features such as a cleft palate, Down syndrome or crossed eyes. Participants rated each baby's attractiveness on a scale of zero to 100, and used keystrokes to make the photo stay on the screen longer or disappear faster. © 2009 Discovery Communications, LLC.

Keyword: Sexual Behavior; Emotions
Link ID: 12985 - Posted: 06.24.2010

by Ewen Callaway CLEVER HANS's gift was just too good to be true. The Arabian stallion wowed the crowds in early 20th-century Europe with his apparent ability to stomp out the answers to simple mathematical problems, such as 12 - 3 = 9. He could even add fractions and factorise small numbers (see image). Then in 1907, a German psychologist, Oskar Pfungst, proved that Hans was no animal savant. In a scientific trial of sorts, Pfungst demonstrated that Hans could do arithmetic only when his owner, a maths teacher, or another questioner provided unconscious body cues hinting that Hans had reached the correct answer. With blinkers on or with the questioner hidden, Hans's abilities vanished. So, too, did the notion that animals could count. Much has changed, however, in the century since Clever Hans's ignominious exposure. Few now doubt that primates have a sense of number, and even distantly related animals, including salamanders, honeybees and newly hatched chicks, seem to have the knack, with some able to perform basic arithmetic. What's more, the skills of this growing mathematical menagerie resemble our own innate abilities. Could basic mathematics have evolved hundreds of millions of years ago? "The ability to represent time and space and number is a precondition for having any experience whatsoever," says Randy Gallistel, a psychologist at Rutgers University in Piscataway, New Jersey. © Copyright Reed Business Information Ltd

Keyword: Evolution
Link ID: 12984 - Posted: 06.24.2010

By Katherine Harmon Compared with other mammals, primates—from lemurs to humans—have huge brains. But scientists still don't know exactly why—or even when—our brains ballooned. A new study, published yesterday in Proceedings of the National Academy of Sciences, postulates that even without big brains, early primates were able to do a lot of primatelike things—a finding that calls into question many of the prevailing evolutionary theories. "At the beginning, we didn't have an exceptionally large brain," says Jonathan Bloch, an associate curator of vertebrate paleontology at the University of Florida's Florida Museum of Natural History and co-author of the paper, talking about primates in general. To explain the expansion in primates' brains, researchers have put forth various possible mechanisms. Tree dwelling, for instance, may have required more brainpower to coordinate muscles and joints for life off the ground. Changes in diet, too, such as consuming fruits instead of leaves, could have led to more calories being available for brain development. Bloch and his colleagues, however, propose that the owner of the rare, 54-million-year-old skull, an Ignacius graybullianus from an extinct side branch of the primate family tree, was already doing these things with a decidedly nonprimate brain. Not only was the I. graybullianus's brain about two thirds the relative size of those of the smallest modern primates, "it doesn't look anything like a primate's brain," says Richard Kay, a professor of evolutionary anthropology at Duke University who wasn't involved in the study but was first to describe this particular skull (in 1989). If forced to come up with a modern-day comparison, he says, "I'd be looking at a hedgehog." © 1996-2009 Scientific American Inc.

Keyword: Evolution
Link ID: 12983 - Posted: 06.24.2010

By Peter F. MacNeilage, Lesley J. Rogers and Giorgio Vallortigara The left hemisphere of the human brain controls language, arguably our greatest mental attribute. It also controls the remarkable dexterity of the human right hand. The right hemisphere is dominant in the control of, among other things, our sense of how objects interrelate in space. Forty years ago the broad scientific consensus held that, in addition to language, right-handedness and the specialization of just one side of the brain for processing spatial relations occur in humans alone. Other animals, it was thought, have no hemispheric specializations of any kind. Those beliefs fit well with the view that people have a special evolutionary status. Biologists and behavioral scientists generally agreed that right-handedness evolved in our hominid ancestors as they learned to build and use tools, about 2.5 million years ago. Right-handedness was also thought to underlie speech. Perhaps, as the story went, the left hemisphere simply added sign language to its repertoire of skilled manual actions and then converted it to speech. Or perhaps the left brain’s capacity for controlling manual action extended to controlling the vocal apparatus for speech. In either case, speech and language evolved from a relatively recent manual talent for toolmaking. The right hemisphere, meanwhile, was thought to have evolved by default into a center for processing spatial relations, after the left hemisphere became specialized for handedness. In the past few decades, however, studies of many other animals have shown that their two brain hemispheres also have distinctive roles. Despite those findings, prevailing wisdom continues to hold that people are different. Many investigators still think the recently discovered specializations of the two brain hemispheres in nonhumans are unrelated to the human ones; the hemispheric specializations of humans began with humans. © 1996-2009 Scientific American Inc.

Keyword: Laterality; Evolution
Link ID: 12982 - Posted: 06.24.2010

by Ewen Callaway Some fathers show their affection by spending time with their children, others spoil their kids rotten. Some fish, on the other hand, value their offspring so much that they devour them before a predator gets the chance. Savage as it may seem, filial cannibalism makes perfect sense for animals such as sand gobies that invest time and energy in raising large numbers of offspring, says Ashley Chin-Baarstad, a biologist at Purdue University in West Lafayette, Indiana, who led the study. In a role reversal of sorts, male sand gobies tend the eggs from multiple females, who go off on a search for more mates. But a long summer breeding season gives the males ample time to raise multiple broods and, rather than waiting until the eggs have hatched, sometimes they simply make a snack of them. "They've decided it's just not worth it right now and for whatever reason they want to leave," Baarstad says. By eating their eggs, they can at least recoup some of their investment. To determine under what circumstances sand gobies decide to eat their offspring, Baarstad's team mated dozens of males and females in outdoor tanks that mimicked conditions in the wild. Males kept close guard on their hundreds of eggs, all buried safely in the sand. © Copyright Reed Business Information Ltd

Keyword: Sexual Behavior; Stress
Link ID: 12981 - Posted: 06.24.2010

By Lynne Peeples Music may calm the savage beast or, at least, make the workday seem shorter. A new study now adds cardiovascular health to the list of music's potential benefits, suggesting it can directly trigger physiological changes that modulate blood pressure, heart rate and respiration. "Music induces a continuous, dynamic—and to some extent predictable—change in the cardiovascular system," said Luciano Bernardi, a professor of medicine at the University of Pavia in Italy and lead author on the paper published in the journal Circulation, in a statement. Understanding the mechanisms of how swelling crescendos and deflating decrescendos affect our physiology, he suggests, could lead to potential new therapies for stroke and other conditions. Bernardi and his colleagues had previously found that changes in the cardiovascular and respiratory systems mirrored musical tempo. To extend this knowledge to the body's response to changing rhythms, they enlisted 24 volunteers—half experienced singers, the remainder with no musical training. While participants listened to five random selections of Beethoven, Bach, Puccini and other classical artists as well as a two-minute segment of silence, monitors recorded physiological signals. The researchers found that selections with crescendos, especially those with a series of them (think: Queen's Bohemian Rhapsody), led to proportional constriction of blood vessels and increases in blood pressure, heart rate and respiration. © 1996-2009 Scientific American Inc.

Keyword: Hearing; Emotions
Link ID: 12980 - Posted: 06.24.2010

Women who suffer from migraine headaches in middle age accompanied by neurological aura (visual disturbances, dizziness or numbness that can precede migraines) are more likely to have damage to brain tissue in the cerebellum later in life, according to a study by researchers at the National Institute on Aging (NIA) of the National Institutes of Health, the Uniformed Services University of the Health Sciences and the Icelandic Heart Association in Reykjavik. Researchers noted that many people have these types of "silent" brain lesions, but their effect on physical and cognitive function in older people is not well studied. The study appears in the June 24, 2009, issue of the Journal of the American Medical Association. The researchers found that women are more susceptible than men to localized brain tissue damage identified on magnetic resonance images (MRI) and that women who reported having migraines with aura were almost twice as likely to have such damage in the cerebellum as women who reported not having headaches. Researchers noted that while the study shows an association in women between migraine and cerebellar tissue damage later in life, the functional significance of such brain changes remains an open question. The cerebellum is located in the lower back side of the brain and is involved in functions such as motor activity, balance and cognition. Migraine headaches affect approximately 11 percent of adults and 5 percent of children worldwide and are more common in women than in men. Migraines are often accompanied by extreme sensitivity to light and sound, nausea and vomiting. Some individuals with migraine also experience neurological aura symptoms, including temporary visual disturbances that can appear as flashing lights, zig-zag lines or loss of vision.

Keyword: Pain & Touch
Link ID: 12979 - Posted: 06.25.2009

By TARA PARKER-POPE As head of the Food and Drug Administration, Dr. David A. Kessler served two presidents and battled Congress and Big Tobacco. But the Harvard-educated pediatrician discovered he was helpless against the forces of a chocolate chip cookie. In an experiment of one, Dr. Kessler tested his willpower by buying two gooey chocolate chip cookies that he didn’t plan to eat. At home, he found himself staring at the cookies, and even distracted by memories of the chocolate chunks and doughy peaks as he left the room. He left the house, and the cookies remained uneaten. Feeling triumphant, he stopped for coffee, saw cookies on the counter and gobbled one down. “Why does that chocolate chip cookie have such power over me?” Dr. Kessler asked in an interview. “Is it the cookie, the representation of the cookie in my brain? I spent seven years trying to figure out the answer.” The result of Dr. Kessler’s quest is a fascinating new book, “The End of Overeating: Taking Control of the Insatiable American Appetite” (Rodale). During his time at the Food and Drug Administration, Dr. Kessler maintained a high profile, streamlining the agency, pushing for faster approval of drugs and overseeing the creation of the standardized nutrition label on food packaging. But Dr. Kessler is perhaps best known for his efforts to investigate and regulate the tobacco industry, and his accusation that cigarette makers intentionally manipulated nicotine content to make their products more addictive. Copyright 2009 The New York Times Company

Keyword: Obesity
Link ID: 12978 - Posted: 06.24.2010

By NICHOLAS BAKALAR Have to solve a problem? Try taking a nap. REM, not incubation, improves creativity by priming associative networks (The Proceedings of the National Academy of Sciences) But it has to be the right kind of nap — one that includes rapid eye movement, or REM, sleep, the kind that includes dreams. Researchers led by Sara C. Mednick, an assistant professor of psychiatry at the University of California, San Diego, gave 77 volunteers word-association tests under three before-and-after conditions: spending a day without a nap, napping without REM sleep and napping with REM sleep. Just spending the day away from the problem improved performance; people who stayed awake did a little better on the 5 p.m. session than they had done on the 9 a.m. test. Taking a nap without REM sleep also led to slightly better results. But a nap that included REM sleep resulted in nearly a 40 percent improvement over the pre-nap performance. The study, published June 8 in The Proceedings of the National Academy of Sciences, found that those who had REM sleep took longer naps than those who napped without REM, but there was no correlation between total sleep time and improved performance. Only REM sleep helped. Copyright 2009 The New York Times Company

Keyword: Sleep; Learning & Memory
Link ID: 12977 - Posted: 06.24.2010

By NATALIE ANGIER Spoken clearly, the sounds “dah” and “bah” are easy to distinguish. Yet if you play a film clip in which the soundtrack says “dah” while the image on the screen shows a mouth saying “bah,” people will swear they heard “bah.” If you ask people to count the number of times that a light flashes, and you flash the light seven times together with a sequence of eight beeping tones, people will say the light flashed eight times. When confronted with conflicting pieces of information, the brain decides which sense to trust. In the first scenario, those clearly percussing lips could never be articulating a “d,” and so vision claimed the upper hand. But on matters that demand a temporal analysis, and making sense of similar sounds in a sequence, the brain reflexively counts on hearing. Click click click. You can listen to a series of clicks at 20 beats per second and know they are separate clicks rather than a single continuous tone. Run a series of images together at 20 frames per second and — welcome to the movies. “The temporal resolution of our vision,” said Barbara Shinn-Cunningham of Boston University, “is an order of magnitude slower than what our auditory system can cope with.” It’s easy to take hearing for granted, that sprawling stereophonic Babylonia where the gates never close and there are soapboxes for all. You can shut your eyes against a bright sun or avert your gaze from a grim scene. But when one neighbor’s leaf blower sets off another neighbor’s car alarm, hey, where are my earlids? We’ve been called the visual primate, and the size of our visual cortex dwarfs the neural platform assigned to audition. Most people, when asked, claim they would rather lose their hearing than their sight. Copyright 2009 The New York Times Company

Keyword: Hearing
Link ID: 12976 - Posted: 06.24.2010

By HENRY FOUNTAIN A few years ago, researchers determined that when male mice are courting, they produce ultrasonic vocalizations that have an elaborate structure, similar to bird songs. Left unanswered was the question of whether mice sing for a similar purpose — to mark their territory and attract mates. Kurt Hammerschmidt of the German Primate Center in Göttingen and colleagues have provided a partial answer to that question. In a paper in Biology Letters, they report that male mice songs definitely elicit interest from the opposite sex. The researchers exposed females to the recorded songs of males, to calls made by newborn pups and to control sounds. They found that the females responded only to the males’ songs, by approaching the source of the sound. But Dr. Hammerschmidt said there were some surprises in the data. Females became habituated to the male songs very quickly, and only responded the first time they heard the sounds. Dr. Hammerschmidt said that this may be because the songs are important only when males are close by. So if a female hears a song but then doesn’t actually see a mate, she may lose interest. Copyright 2009 The New York Times Company

Keyword: Hearing; Sexual Behavior
Link ID: 12975 - Posted: 06.24.2010