By Susan Milius Hey evolution, thanks for nothing. When a mammal embryo develops, its middle ear appears to form in a pop-and-patch way that seals one end with substandard, infection-prone tissue. “The way evolution works doesn’t always create the most perfect, engineered structure,” says Abigail Tucker, a developmental biologist at King’s College London. “Definitely, it’s made an ear that’s slightly imperfect.” The mammalian middle ear catches sound and transfers it, using three tiny bones that jiggle against the eardrum, to the inner ear chamber. Those three bones — the hammer, anvil and stirrup — are a distinctive trait that distinguishes the group from other evolutionary lineages. Research in mouse embryos finds that the middle ear begins as a pouch of tissue. Then its lining ruptures at one end and the break lets in a different kind of tissue, which forms the tiny bones of the middle ear. This intruding tissue originates from what’s called the embryo’s neural crest, a population of cells that gives rise to bone and muscle. Neural crest tissue has never been known before to create a barrier in the body. Yet as the mouse middle ear forms, this tissue creates a swath of lining that patches the rupture, Tucker and colleague Hannah Thompson, report in the March 22 Science. © Society for Science & the Public 2000 - 2013

Keyword: Hearing; Aggression
Link ID: 17947 - Posted: 03.25.2013

By JANE E. BRODY Noise, not age is the leading cause of hearing loss. Unless you take steps now to protect to your ears, sooner or later many of you — and your children — will have difficulty understanding even ordinary speech. Tens of millions of Americans, including 12 percent to 15 percent of school-age children, already have permanent hearing loss caused by the everyday noise that we take for granted as a fact of life. “The sad truth is that many of us are responsible for our own hearing loss,” writes Katherine Bouton in her new book, “Shouting Won’t Help: Why I — and 50 Million Other Americans — Can’t Hear You.” The cause, she explains, is “the noise we blithely subject ourselves to day after day.” While there are myriad regulations to protect people who work in noisy environments, there are relatively few governing repeated exposure to noise outside the workplace, from portable music devices, rock concerts, hair dryers, sirens, lawn mowers, leaf blowers, vacuum cleaners, car alarms and countless other sources. We live in a noisy world, and every year it seems to get noisier. Ms. Bouton notes that the noise level inside Allen Fieldhouse at the University of Kansas often exceeds that of a chain saw. After poor service, noise is the second leading complaint about restaurants. Proprietors believe that people spend more on food and drink in bustling eateries, and many have created new venues or retrofitted old ones to maximize sound levels. Copyright 2013 The New York Times Company

Keyword: Hearing
Link ID: 17946 - Posted: 03.25.2013

by Trevor Quirk Many smartphones claim to filter out background noise, but they've got nothing on the human brain. We can tune in to just one speaker at a noisy cocktail party with little difficulty—an ability that has been a scientific mystery since the early 1950s. Now, researchers argue that the competing noise of other partygoers is filtered out in the brain before it reaches regions involved in higher cognitive functions, such as language and attention control. Their experiments were the first to demonstrate this process. The scientists didn't do anything as social as attend a noisy party. Instead, Charles Schroeder, a psychiatrist at the Columbia University College of Physicians and Surgeons in New York City, and colleagues recorded the brain activity of six people with intractable epilepsy who required brain surgery. In order to identify the part of their brains responsible for seizures, the patients underwent 1 to 4 weeks of observation through electrocorticography (ECoG), a technique that provides precise neural recordings via electrodes placed directly on the surface of the brain. Schroeder and his team, using the ECoG data, conducted their experiments during this time. The researchers showed the patients two videos simultaneously, each of a person telling a 9- to 12-second story; they were asked to concentrate on just one speaker. To determine which neural recordings corresponded to the "ignored" and "attended" speech, the team reconstructed speech patterns from the brain's electrical activity using a mathematical model. The scientists then matched the reconstructed patterns with the original patterns coming from the ignored and attended speakers. © 2010 American Association for the Advancement of Science.

Keyword: Attention; Aggression
Link ID: 17876 - Posted: 03.07.2013

by Tim Wall Some feathered crooners may advertise their size to females by hitting the low notes. Ornithologists at the Max Planck Institute found that only bigger-bodied birds belt out the bass. The physical size of some birds may put a limit on the frequency of the birds’ songs, according to a study published in PLOS ONE. Since only a larger males hit lower notes, females may be able to use deeper voices as a reliable measure of a male’s size. Size matters to some songbird species, with females preferring larger males, so vocal limitations could affect some birds’ love lives. The songs of purple-crowned fairy-wrens, Malurus coronatus coronatus, hit a range of notes. However the study found that in some songs, larger body size related to lower-pitched singing ability. Further study will be needed to prove a relationship among body size, singing frequency and sexual success in fairy-wrens. The authors suggested that body size may be just one of many characteristics advertized by fairy-wrens songs. The authors also noted that low-frequency singing ability may have resulted from good health as the male fairy-wrens grew up. Better health may have allowed better development of singing structures in the birds’ anatomies. The same healthy conditions could have also resulted in larger size. So size and singing would be correlated, but not causally related. © 2013 Discovery Communications, LLC.

Keyword: Sexual Behavior; Aggression
Link ID: 17856 - Posted: 02.27.2013

Diet pop and other artificially sweetened products may cause us to eat and drink even more calories and increase our risk for obesity and Type 2 diabetes, researchers are learning. Former McGill University researcher Dana Small specializes in the neuropsychology of flavour and feeding at Yale University in New Haven, Conn. Small said there's mounting evidence that artificial sweeteners have a couple of problematic effects. Sugar substitutes such as sucralose and aspartame are more intensely sweet than sugar and may rewire taste receptors so less sweet, healthier foods aren't as enjoyable, shifting preferences to higher calorie, sweeter foods, she said. Small and some other researchers believe artificial sweeteners interfere with brain chemistry and hormones that regulate appetite and satiety. For millennia, sweet taste signalled the arrival of calories. But that's no longer the case with artificial sweeteners. "The sweet taste is no longer signalling energy and so the body adapts," Small said in an interview with CBC News. "It's no longer going to release insulin when it senses sweet because sweet now is not such a good predictor of the arrival of energy." Susan Swithers, a psychology professor at Purdue University in West Lafayette, Ind., studies behavioural neuroscience. "Exposure to high-intensity sweeteners could change the way that sweet tastes are processed," she says. © CBC 2013

Keyword: Obesity; Aggression
Link ID: 17825 - Posted: 02.19.2013

By SINDYA N. BHANOO Humans and many other mammals see and hear in stereo. But what about smell? “People have wondered for a long time whether smell has this component as well,” said Kenneth C. Catania, a biologist at Vanderbilt University. Now he and colleagues report in the journal Nature Communications that common moles, which are blind, have the ability and use it to swiftly locate prey. Dr. Catania created a chamber with food wells spaced around a semicircle and watched as moles detected the food. The chamber was sealed, so changes in air pressure would indicate that the animals were sniffing. Moving their noses back and forth, the moles zeroed in on the food in less than five seconds. Dr. Catania then blocked one of the moles’ nostrils with a plastic tube. When the left nostril was blocked, the moles veered off to the right, and when the right was blocked, they veered to left. Although they were still able to find the food, it took them much longer. To confirm that the moles use stereo sniffing, Dr. Catania put plastic tubes in both nostrils and then crossed them. This confused the moles, causing them to think that food to their right was actually located to their left. But their response confirmed that the moles in fact use stereo sniffing, Dr. Catania said. Previous research indicates that rats can smell in stereo, and there are suggestions that sharks and ants can, too. “The jury is still out on how many animals can do this, and that will tell us how primitive this is,” Dr. Catania said. “If only a few animals do it, then it may have evolved recently.” So can humans smell in stereo? Unlikely, he said. © 2013 The New York Times Company

Keyword: Chemical Senses (Smell & Taste)
Link ID: 17821 - Posted: 02.19.2013

By Rachel Ehrenberg BOSTON — For the first time, researchers have snapped pictures of mouse inner ear cells using an approach that doesn’t damage tissue or require elaborate dyes. The approach could offer a way to investigate hearing loss — the most common sensory deficit in the world — and may help guide the placement of cochlear devices or other implants. Inner ear damage and the deafness that results have long challenged scientists. The small delicate cochlea and associated parts are encased in the densest bone in the body and near crucial anatomical landmarks, including the jugular vein, carotid artery and facial nerve, which make them difficult to access. With standard anatomical imaging techniques such as MRI, the inner ear just looks like a small grey blob. “We can’t biopsy it, we can’t image it, so it’s very difficult to figure out why people are deaf,” said ear surgeon and neuroscientist Konstantina Stankovic of the Massachusetts Eye and Ear Infirmary in Boston. Stankovic and her colleagues took a peek at inner ear cells using an existing technique called two-photon microscopy. This approach shoots photons at the target tissue, exciting particular molecules that then emit light. The researchers worked with mice exposed to 160 decibels of sound for two hours —levels comparable to the roaring buzz of a snowmobile or power tools. Then they removed the rodents’ inner ears, which includes the spiraled, snail-shaped cochlea and other organs. Instead of cutting into the cochlea, the researchers peered through the “round window” — a middle ear opening covered by a thin membrane that leads to the cochlea. © Society for Science & the Public 2000 - 2013

Keyword: Hearing; Aggression
Link ID: 17820 - Posted: 02.19.2013

By Alan Boyle, Science Editor, NBC News BOSTON — Neuroscientists are following through on the promise of artificially enhanced bodies by creating the ability to "feel" flashes of light in invisible wavelengths, or building an entire virtual body that can be controlled via brain waves. "Things that we used to think were hoaxes or science fiction are fast becoming reality," said Todd Coleman, a bioengineering professor at the University of California at San Diego. Coleman and other researchers surveyed the rapidly developing field of neuroprosthetics in Boston this weekend at the annual meeting of the American Association for the Advancement of Science. One advance came to light just in the past week, when researchers reported that they successfully wired up rats to sense infrared light and move toward the signals to get a reward. "This was the first attempt … not to restore a function but to augment the range of sensory experience," said Duke University neurobiologist Miguel Nicolelis, the research team's leader. The project, detailed in the journal Nature Communications, involved training rats to recognize a visible light source and poke at the source with its nose to get a sip of water. Then electrodes were implanted in a region of the rats' brains that is associated with whisker-touching. The electrodes were connected to an infrared sensor on the rats' heads, which stimulated the target neurons when the rat was facing the source of an infrared beam. Then the visible lights in the test cage were replaced by infrared lights. © 2013 NBCNews.com

Keyword: Pain & Touch; Aggression
Link ID: 17816 - Posted: 02.18.2013

by Hal Hodson CAN YOU imagine feeling Earth's magnetic field on the tip of your tongue? Strangely, this is now possible, using a device that converts the tongue into a "display" for output from environmental sensors. Gershon Dublon of the Massachusetts Institute of Technology devised a small pad containing electrodes in a 5 × 5 grid. Users put the pad, which Gershon calls Tongueduino, on their tongue. When hooked up to an electronic sensor, the pad converts signals from the sensor into small pulses of electric current across the grid, which the tongue "reads" as a pattern of tingles. Dublon says the brain quickly adapts to new stimuli on the tongue and integrates them into our senses. For example, if Tongueduino is attached to a sensor that detects Earth's magnetic field, users can learn to use their tongue as a compass. "You might not have to train much," he says. "You could just put this on and start to perceive." Dublon has been testing Tongueduino on himself for the past year using a range of environmental sensors. He will now try the device out on 12 volunteers. Blair MacIntyre at the Georgia Institute of Technology in Atlanta says a wireless version of Tongueduino could prove useful in augmented reality applications that deliver information to users inconspicuously, without interfering with their vision or hearing. "There's a need for forms of awareness that aren't socially intrusive," he says. Even Google's much-publicised Project Glass will involve wearing a headset, he points out. © Copyright Reed Business Information Ltd.

Keyword: Chemical Senses (Smell & Taste); Aggression
Link ID: 17806 - Posted: 02.16.2013

By Emily Chung, CBC News Among musicians who learned to play an instrument before the age of seven, earlier training was linked to more connections in the area of the brain that co-ordinates both hands.Among musicians who learned to play an instrument before the age of seven, earlier training was linked to more connections in the area of the brain that co-ordinates both hands. (Jorge Silva/Reuters) Starting piano or violin lessons before the age of seven appears to cause permanent changes to the brain that are linked to better motor skills. Those changes in brain development don't occur in people who learn to play an instrument when they are older, a new study has found. "What we think is that it doesn't mean you can't be an amazing musician if you start later — just that if you start earlier it may give you some of these specific abilities that are helpful," said Virginia Penhune, a Concordia University psychologist who co-authored the research with two of her doctoral students and McGill University neuropsychologist Robert Zatorre. The Montreal researchers gave a test of motor skills to and scanned the brains of 36 musicians who were either enrolled in a university music program or performed professionally, and who had an average of 16 years experience playing musical instruments. Half of them began their musical training between age three and seven, while the other half started between the ages of eight and 18, but both groups had a comparable level of experience. The study also tested 17 non-musicians. © CBC 2013

Keyword: Development of the Brain; Aggression
Link ID: 17804 - Posted: 02.14.2013

by Lizzie Wade When a male wasp decides it's time to settle down and start a family, he releases a chemical calling card in the form of pheromones, broadcasting his location, his availability, and, most importantly, his identity. Most other kinds of insects will either ignore his signal or be repelled by it, but female wasps of his own species will buzz over and get down to business. But how and why did different pheromone blends—and the species that prefer them—evolve in the first place? A new study offers a possible solution to this long-standing evolutionary mystery, suggesting that new sex pheromones may evolve through genetic mutation before potential mates develop the ability to detect them. Scientists have long been impressed by the perfect harmony of chemical communication among insects, especially when it comes to choosing mates by detecting and responding to the sex pheromones of only their own species. But scientists were puzzled by how such a delicate system evolved. If female wasps respond to only a specific blend of pheromones, males that produce even a subtly different blend shouldn't have much luck mating and passing on their mutant genes. It seemed that in order for males to evolve new pheromones, the female insects would need some preexisting adaptation that would cause them to prefer the new chemical blend. But how could they evolve a preference for something they had never encountered and should, logic suggests, find off-putting? In essence, the question is which came first, a new species or its sex pheromone? In order to answer this question, a team of researchers in Germany turned to the Nasonia vitripennis wasp, a species famous for its propensity to lay its parasitic eggs on doomed fly pupae. When the scientists analyzed the N. vitripennis male sex pheromone, they found it contained two important chemicals, which they call RS and RR. RS also turns up in the male sex pheromones of another species of wasp, N. giraulti, whereas RR appears to be unique. © 2010 American Association for the Advancement of Science.

Keyword: Chemical Senses (Smell & Taste); Aggression
Link ID: 17803 - Posted: 02.14.2013

by Kelli Whitlock Burton Having a conversation in a noisy restaurant can be difficult. For many elderly adults, it's often impossible. But with a little practice, the brain can learn to hear above the din, a new study suggests. Age-related hearing loss can involve multiple components, such as the disappearance of sensory cells in the inner ear. But scientists say that part of the problem may stem from our brains. As we get older, our brains slow down—a natural part of aging called neural slowing. One side effect of this sluggishness is the inability to process the fast-moving parts of speech, particularly consonants at the beginning of words that sound alike, such as "b," "p," "g," and "d." Add background noise to the mix and "bad" may sound like "dad," says Nina Kraus, director of the Auditory Neuroscience Laboratory at Northwestern University in Evanston, Illinois. "Neural slowing especially affects our ability to hear in a noisy background because the sounds we need to hear are acoustically less salient and because noise also taxes our ability to remember what we hear." Building on animal studies that pointed to an increase in neural speed following auditory training, Kraus and colleagues enrolled 67 people aged 55 to 70 years old with no hearing loss or dementia in an experiment. Half the group completed about 2 months of exercises with Brain Fitness, a commercially available auditory training program by Posit Science. (The team has no connection to the company.) The exercises helped participants better identify different speech sounds and distinguish between similar-sounding syllables, such as "ba" or "ta." © 2010 American Association for the Advancement of Science

Keyword: Hearing; Aggression
Link ID: 17800 - Posted: 02.14.2013

By KATHERINE BOUTON At a party the other night, a fund-raiser for a literary magazine, I found myself in conversation with a well-known author whose work I greatly admire. I use the term “conversation” loosely. I couldn’t hear a word he said. But worse, the effort I was making to hear was using up so much brain power that I completely forgot the titles of his books. A senior moment? Maybe. (I’m 65.) But for me, it’s complicated by the fact that I have severe hearing loss, only somewhat eased by a hearing aid and cochlear implant. Dr. Frank Lin, an otolaryngologist and epidemiologist at Johns Hopkins School of Medicine, describes this phenomenon as “cognitive load.” Cognitive overload is the way it feels. Essentially, the brain is so preoccupied with translating the sounds into words that it seems to have no processing power left to search through the storerooms of memory for a response. Over the past few years, Dr. Lin has delivered unwelcome news to those of us with hearing loss. His work looks “at the interface of hearing loss, gerontology and public health,” as he writes on his Web site. The most significant issue is the relation between hearing loss and dementia. In a 2011 paper in The Archives of Neurology, Dr. Lin and colleagues found a strong association between the two. The researchers looked at 639 subjects, ranging in age at the beginning of the study from 36 to 90 (with the majority between 60 and 80). The subjects were part of the Baltimore Longitudinal Study of Aging. None had cognitive impairment at the beginning of the study, which followed subjects for 18 years; some had hearing loss. Copyright 2013 The New York Times Company

Keyword: Hearing; Aggression
Link ID: 17787 - Posted: 02.12.2013

by Jacob Aron The mystery of how our brains perceive sound has deepened, now that musicians have smashed a limit on sound perception imposed by a famous algorithm. On the upside this means it should be possible to improve upon today's gold-standard methods for audio perception. Devised over 200 years ago, the Fourier transform is a mathematical process that splits a sound wave into its individual frequencies. It is the most common method for digitising analogue signals and some had thought that brains make use of the same algorithm when turning the cacophony of noise around us into individual sounds and voices. To investigate, Jacob Oppenheim and Marcelo Magnasco of Rockefeller University in New York turned to the Gabor limit, a part of the Fourier transform's mathematics that makes the determination of pitch and timing a trade-off. Rather like the uncertainty principle of quantum mechanics, the Gabor limit states you can't accurately determine a sound's frequency and its duration at the same time. 13 times better The pair reasoned that if people's hearing obeyed the Gabor limit, this would be a sign that they were using the Fourier transform. But when 12 musicians, some instrumentalists, some conductors, took a series of tests, such as judging slight changes in the pitch and duration of sounds at the same time, they beat the limit by up to a factor of 13. © Copyright Reed Business Information Ltd.

Keyword: Hearing
Link ID: 17775 - Posted: 02.09.2013

By Tina Hesman Saey The common mole may be homely but its nose is a wonder to behold. The eastern American mole, also known as the common mole, tracks down an earthworm treat by recognizing the slightly different odor cues entering each nostril, neurobiologist Kenneth Catania of Vanderbilt University in Nashville reports online February 5 in Nature Communications. The finding suggests that even though mole nostrils are separated by a fraction of a centimeter, each gets its own scent information that can guide an animal’s actions. “It’s an elegant demonstration of what many people suspected,” says Peter Brunjes, a neuroscientist at the University of Virginia. Previous experiments with people and rats had reached contradictory conclusions regarding whether smell, like sight and hearing, is a bilateral sense. Catania never expected the common mole, Scalopus aquaticus, to have uncommon abilities. “I’ve described it as the unlucky, stupid cousin of the star-nosed mole,” he says. Star-nosed moles, Condylura cristata, have an incredible sense of touch in their tentacled schnozzes and are among the world’s fastest foragers. But compared with other mole species, the eastern American mole has a poor sense of touch. The animals also can’t see. Catania turned to common moles because he thought they would have a hard time finding food and could be tested against star-nosed moles in future experiments. But when he placed a common mole in a semicircular arena with a chopped up bit of earthworm as bait, he says, “it would wiggle its nose around and go in a beeline toward the food.” © Society for Science & the Public 2000 - 2013

Keyword: Chemical Senses (Smell & Taste)
Link ID: 17768 - Posted: 02.06.2013

By C. CLAIBORNE RAY Q. Nearing 70, I have increasing difficulty hearing conversations, yet music in restaurants is too loud. Why? A. Age-related hearing loss, called presbycusis, is characterized by loss of hair cells in the base of the cochlea, or inner ear, that are attuned to capture and transmit high-frequency sounds, said Dr. Anil K. Lalwani, director of otology, neurotology and skull-base surgery at NewYork-Presbyterian Hospital/Columbia University Medical Center. Loss of high-frequency hearing leads to deterioration in the ability to distinguish words in conversation. Additionally, any noise in the environment leads to even greater loss in clarity of hearing. “Contrary to expectation, presbycusis is also associated with sensitivity to loud noises,” Dr. Lalwani said. “This is due to a poorly understood phenomenon called recruitment.” Normally, a specific sound frequency activates a specific population of hair cells located at a specific position within the cochlea. With hearing loss, this specificity is lost, and a much larger population of hair cells in the adjacent areas is “recruited” and also activated, producing sensitivity to noise. “Patients with presbycusis perceive an incremental increase in loudness to be much greater than those with normal hearing,” he said. “This explains why the elderly parent complains that ‘I am not deaf!’ ” when a son or daughter repeats a misheard sentence. © 2013 The New York Times Company

Keyword: Hearing; Aggression
Link ID: 17760 - Posted: 02.05.2013

By James Gallagher Health and science reporter, BBC News A tiny "genetic patch" can be used to prevent a form of deafness which runs in families, according to animal tests. Patients with Usher syndrome have defective sections of their genetic code which cause problems with hearing, sight and balance. A study, published in the journal Nature Medicine, showed the same defects could be corrected in mice to restore some hearing. Experts said it was an "encouraging" start. There are many types of Usher syndrome tied to different errors in a patient's DNA - the blueprint for building every component of the body. One of those mutations runs in families descended from French settlers in North America. When they try to build a protein called hormonin, which is needed to form the tiny hairs in the ear that detect sound, they do not finish the job. It results in hearing loss at birth and has a similar effect in the eye where it causes a gradual loss of vision. Scientists at the Rosalind Franklin University of Medicine and Science, in Chicago in the US, designed a small strip of genetic material which attaches to the mutation and keeps the body's factories building the protein. There has been something of a flurry of developments in restoring hearing in the past year. BBC © 2013

Keyword: Hearing; Aggression
Link ID: 17759 - Posted: 02.05.2013

by Elizabeth Pennisi Though often associated with dirty environments, cockroaches are actually quite fastidious, especially when it comes to their antennae. They clean them often by grabbing one in with a front leg and drawing it through their mouth. Researchers have long observed that many insects groom themselves, and now they know why. When scientists restrained American cockroaches or prevented grooming by gluing mouthparts for 24 hours, they noticed a shiny, waxy buildup on the antennae that clogs the tiny pores that lead to odor-sensing cells. Measurements of the electrical activity in those cells in response to sex-attractant and food odors showed that the gunk interfered with the roach's sense of smell, they report online today in the Proceedings of the National Academy of Sciences. The insects appear to produce wax continuously, likely to keep from drying out, and grooming helps remove the excess as well as dust and other foreign chemicals that land on the antennae and get trapped in the gunk. Carpenter ants, houseflies, and German cockroaches also suffered from gunk overload when prohibited from grooming, suggesting that fastidiousness is widespread. © 2010 American Association for the Advancement of Science

Keyword: Chemical Senses (Smell & Taste)
Link ID: 17755 - Posted: 02.05.2013

by Elizabeth Devitt Birds may not have big brains, but they know how to navigate. They wing around town and across continents with amazing accuracy, while we watch and wonder. Biologists believe that sight, smell, and an internal compass all contribute to avian orienteering. But none of these skills completely explains how birds fly long distances or return home from places they've never been. A new study proposes that the animals use infrasound—low-level background noise in our atmosphere—to fly by "images" they hear. These acoustical maps may also explain how other creatures steer. Scientists have long considered infrasound as a navigational cue for birds. But until U.S. Geological Survey geophysicist Jonathan Hagstrum in Menlo Park, California, became intrigued by the unexplained loss of almost 60,000 pigeons during a race from France to England in 1997, no one pinpointed how the process worked. The race went bust when the birds' flight route crossed that of a Concorde jet, and Hagstrum wanted to know why. "When I realized the birds in that race were on the same flight path as the Concorde, I knew it had to be infrasound," he says. The supersonic plane laid down a sonic boom when most of the animals were flying across the English Channel. Normally, infrasound is generated when deep ocean waves send pressure waves reverberating into the land and atmosphere. Infrasound can come from other natural causes, such as earthquakes, or humanmade events, such as the acceleration of the Concorde. The long, slow waves move across vast distances. Although humans can't hear them, birds and other animals are able to tune in. © 2010 American Association for the Advancement of Science

Keyword: Hearing; Aggression
Link ID: 17746 - Posted: 02.02.2013

By Jason Palmer Science and technology reporter, BBC News A controversial theory that the way we smell involves a quantum physics effect has received a boost, following experiments with human subjects. It challenges the notion that our sense of smell depends only on the shapes of molecules we sniff in the air. Instead, it suggests that the molecules' vibrations are responsible. A way to test it is with two molecules of the same shape, but with different vibrations. A report in PLOS ONE shows that humans can distinguish the two. Tantalisingly, the idea hints at quantum effects occurring in biological systems - an idea that is itself driving a new field of science, as the BBC feature article Are birds hijacking quantum physics? points out. But the theory - first put forward by Luca Turin, now of the Fleming Biomedical Research Sciences Centre in Greece - remains contested and divisive. The idea that molecules' shapes are the only link to their smell is well entrenched, but Dr Turin said there were holes in the idea. He gave the example of molecules that include sulphur and hydrogen atoms bonded together - they may take a wide range of shapes, but all of them smell of rotten eggs. "If you look from the [traditional] standpoint... it's really hard to explain," Dr Turin told BBC News. "If you look from the standpoint of an alternative theory - that what determines the smell of a molecule is the vibrations - the sulphur-hydrogen mystery becomes absolutely clear." BBC © 2013

Keyword: Chemical Senses (Smell & Taste)
Link ID: 17724 - Posted: 01.28.2013