Links for Keyword: Chemical Senses (Smell & Taste)

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By MARY ROACH WAGENINGEN, THE NETHERLANDS — When I told people I was traveling to Food Valley, I described it as the Silicon Valley of eating. At this cluster of universities and research facilities, nearly 15,000 scientists are dedicated to improving — or, depending on your sentiments about processed food, compromising — the quality of our meals. At the time I made the Silicon Valley comparison, I did not expect to be served actual silicone. But here I am, in the Restaurant of the Future, a cafeteria at Wageningen University where hidden cameras record diners as they make decisions about what to eat. And here it is, a bowl of rubbery white cubes the size of salad croutons. Andries van der Bilt has brought them from his lab in the brusquely named Department of Head and Neck, at the nearby University Medical Center Utrecht. “You chew them,” he said. The cubes are made of a trademarked product called Comfort Putty, more typically used in its unhardened form for taking dental impressions. Dr. Van der Bilt isn’t a dentist, however. He is an oral physiologist, and he likely knows more about chewing than anyone else in the world. He uses the cubes to quantify “masticatory performance” — how effectively a person chews. I take a cube from the bowl. If you ever, as a child, chewed on a whimsical pencil eraser in the shape of, say, an animal or a piece of fruit, then you have tasted this dish. “I’m sorry.” Dr. Van der Bilt winces. “It’s quite old.” As though fresh silicone might be better. © 2013 The New York Times Company

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell; Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 5: The Sensorimotor System
Link ID: 17949 - Posted: 03.26.2013

by Audrey Carlsen Plenty of us got our fill of green-colored food on St. Patrick's Day. (Green beer, anyone?) But for some people, associating taste with color is more than just a once-a-year experience. These people have synesthesia — a neurological condition in which stimulation of one sense (e.g., taste) produces experiences in a totally different sense (e.g., sight). According to researcher Sean Day, approximately one in 27 people has some form of synesthesia. We've covered this phenomenon in the past. And I'm a synesthete myself — I see letters and numbers in color, and associate sounds with shapes and textures. But only a very few people — maybe only 1 percent of synesthetes — have sensory crossovers that affect their relationship with food and drink. Jaime Smith is one of those people. He's a sommelier by trade, and he has a rare gift: He smells in colors and shapes. For Smith, who lives in Las Vegas, a white wine like Nosiola has a "beautiful aquamarine, flowy, kind of wavy color to it." Other smells also elicit three-dimensional textures and colors on what he describes as a "projector" in his mind's eye. This "added dimension," Smith says, enhances his ability to appraise and analyze wines. "I feel that I have an advantage over a lot of people, particularly in a field where you're judged on how good of a smeller you are," he says. ©2013 NPR

Related chapters from BP7e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain; Chapter 18: Attention and Higher Cognition
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 14: Attention and Consciousness
Link ID: 17915 - Posted: 03.19.2013

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

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 17821 - Posted: 02.19.2013

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.

Related chapters from BP7e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain; Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 17806 - Posted: 02.16.2013

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.

Related chapters from BP7e: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 17803 - Posted: 02.14.2013

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

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 17768 - Posted: 02.06.2013

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

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 17755 - Posted: 02.05.2013

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

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 17724 - Posted: 01.28.2013

by Sarah C. P. Williams You might not be able to pick your fingerprint out of an inky lineup, but your brain knows what you smell like. For the first time, scientists have shown that people recognize their own scent based on their particular combination of major histocompatibility complex (MHC) proteins, molecules similar to those used by animals to choose their mates. The discovery suggests that humans can also exploit the molecules to differentiate between people. "This is definitely new and exciting," says Frank Zufall, a neurobiologist at Saarland University's School of Medicine in Homburg, Germany, who was not involved in the work. "This type of experiment had never been done on humans before." MHC peptides are found on the surface of almost all cells in the human body, helping inform the immune system that the cells are ours. Because a given combination of MHC peptides—called an MHC type—is unique to a person, they can help the body recognize invading pathogens and foreign cells. Over the past 2 decades, scientists have discovered that the molecules also foster communication between animals, including mice and fish. Stickleback fish, for example, choose mates with different MHC types than their own. Then, in 1995, researchers conducted the now famous "sweaty T-shirt study," which concluded that women prefer the smell of men who have different MHC genes than themselves. But no studies had shown a clear-cut physiological response to MHC proteins. © 2010 American Association for the Advancement of Science

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 17716 - Posted: 01.26.2013

by Kai Kupferschmidt Human beings tend to avoid places that smell of urine. But to mice, there is something positively addictive about the scent; they like to go back to a spot where they found the excretions again and again. Now, researchers have discovered that this behavior is triggered by a single protein in the urine of male mice. Mice use scent to mark their territory, advertise their social dominance, and convey information about their health and reproductive status. But these are usually volatile pheromones that disperse quickly, and it has remained unclear what exactly stimulates a female to be attracted to a specific male. Previous research had shown that female laboratory mice often return to a place where they have come across cage bedding soiled by males. Now, researchers at the University of Liverpool in the United Kingdom have confirmed this. Female mice spent five times as much time in a place where they had encountered a dish with male urine than at a place where they encountered water. Just 10 minutes of exposure to the urine was enough for the mice to show this place preference even after 14 days. However, if the mice were prevented from by a mesh screen touching the urine with their nose, the place seemed to lose its attractiveness. "That suggested that the story was not as simple as everybody assumed and volatile pheromones were not responsible," says behavioral ecologist Jane Hurst, one of the authors of the study. By separating the urine into different fractions, the scientists showed that a protein called darcin that they had identified in 2005—and which mice can only detect if their noses touch the urine—is responsible for the frequent visits. Pure darcin, produced in cell culture in the lab, elicited the same reaction, the authors report online today in Science. © 2010 American Association for the Advancement of Science.

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 8: Hormones and Sex
Link ID: 17606 - Posted: 12.14.2012

By David Brown, We all know that when it comes to enjoying food, taste and smell go hand in hand. But how and where they hold hands in the neural circuits of the brain has been something of a mystery. Neuroscientists have known for a while that odor receptors in the nose send signals to the the brain’s taste center, also known as the gustatory cortex. But does the converse happen? Do taste receptors in the tongue talk to the smell center, the olfactory cortex? New research suggests the answer is yes. The smell center gets and uses information from the tongue even if an animal is not consciously sniffing — or even inhaling. “We know there is a sense of smell in the taste system. What’s new is that we now know that smell, like taste, can’t really work on its own, either,” said Donald B. Katz, a neuroscientist at Brandeis University who co-authored the study. “What this means is that the different senses are really interacting with each other at a much earlier level than previously thought,” said Joost X. Maier, the postdoctoral researcher at Brandeis who did the experiments reported in the current issue of the Journal of Neuroscience. One can construct reasons why this might be the best way to design the brain. But the brain arose by chance, interacting with the world and sculpted by natural selection. For virtually all forms of life, taste and smell were experienced together in the act of finding and consuming food. © 1996-2012 The Washington Post

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 17573 - Posted: 12.04.2012

A fondness for the burn of spicy food has less to do with tolerance and far more to do with personality, according to a new study. Researchers from Pennsylvania State University have found a love of chili is associated with sensation seeking and reward, but found no evidence that chili lovers get desensitized to chili burn over time. "Rather than merely showing reduced response to the irritating qualities of capsaicin (the compound that gives chili its burn) as might be expected—these findings support the hypothesis that personality differences may drive differences in spicy food liking and intake," the authors wrote in the journal Food Quality and Preference. "We always assumed that liking drives intake—we eat what we like and we like what we eat. But no one had actually directly bothered to connect these personality traits of sensation seeking with intake of chilli peppers," says lead author and self-confessed chili lover Professor John Hayes. The discovery of a relationship between fondness for chilli and sensitivity to reward was also new, says Hayes who is an assistant professor of food science at Pennsylvania State University. Nearly one hundred volunteers were given liquid samples of capsaicin and asked to swill it in their mouth for three seconds before spitting out. They were then asked to rate the burning sensation and, in a separate questionnaire, rate their liking of various foods. © CBC 2012

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 17572 - Posted: 12.04.2012

Roger Dobson Love, according to romantics, can have a dramatic effect on the senses: striking lovers blind, deaf or rendering them tongue-tied. But the simple answer to the question of whether any relationship is "the one" seems to be that your ideal man or woman gets up your nose. New research suggests a sense of smell is vital for a good long-term relationship. In the new study, reported in the journal Biological Psychology, researchers looked for the first time at the effect of being born without a sense on smell on men and women's relationships. The research involved analysing data on men and women aged 18 to 46 with no sense of smell and comparing it with information gleaned from a healthy control group. The results showed that men and women who were unable to smell had higher levels of social insecurity, although this manifested itself in different ways. In men, but not in women, it led to fewer relationships. The men with a faulty sense of smell averaged two partners compared with 10 for healthy men. One theory is that the lack of a sense of smell may make men less adventurous. They may have more problems assessing and communicating with other people. They may also be concerned about how they are perceived by others, and worry about their own body odour. © independent.co.uk

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 8: Hormones and Sex
Link ID: 17566 - Posted: 12.03.2012

By Christina Agapakis White is a mixture, made by a combination of signals at equal intensity across a perceptual space. White light can be split up into all the colors of the visible spectrum, and white noise covers a range of frequencies within the audible range. Our other senses don’t have as clearly defined ranges of perception. We can’t give a smell, a taste, or a texture a number the same way that a color or a tone can be defined by a wavelength, but a fascinating recent paper shows that by mixing many different smelly molecules at equal intensities, our perception of the odor will converge on “olfactory white.” The researchers created this strangely neutral smell from different mixtures of up to thirty odors, chosen from a set of 86 molecules that represent a wide range of the kinds of things that we can smell. Human “olfactory stimulus space” contains thousands of molecules, from the fragrant and floral to the putrid. We can distinguish and name many smells, but odors don’t map neatly onto a one dimensional spectrum. Sampling the multidimensional stimulus space of odors requires a much more complicated mapping of the smell universe. The figure on the left shows the position of the 86 molecules within two maps of olfactory stimulus space. The first is based on the way that we perceive odors (perceptual space, A) and the second based on the chemical structures of the molecules (physicochemical space, B). The perceptual map is built with data from Dravnieks’ Atlas of Odor Character Profiles of 144 different molecules. Each smell was compared by 150 professional noses against a list of 146 different odor descriptions like “fruity” “etherish” “decayed” or “seasoning for meat.” © 2012 Scientific American,

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 17547 - Posted: 11.28.2012

by Sid Perkins If you play sounds of many different frequencies at the same time, they combine to produce neutral "white noise." Neuroscientists say they have created an analogous generic scent by blending odors. Such "olfactory white" might rarely, if ever, be found in nature, but it could prove useful in research, other scientists say. Using just a few hundred types of biochemical receptors, each of which respond to just a few odorants, the human nose can distinguish thousands of different odors. Yet humans can't easily identify the individual components of a mixture, even when they can identify the odors alone, says Noam Sobel, a neuroscientist at the Weizmann Institute of Science in Rehovot, Israel. Now, he and his colleagues suggest, various blends made up of a large number of odors all begin to smell the same—even when the blends share no common components. For their study, the researchers used 86 nontoxic odorants that had a wide variety of chemical and physical properties such as molecular structure, molecular weight, and volatility. Those chemicals also spanned a perceptual scale from "pleasant" to "unpleasant" and another such scale on which scents were judged to range from "edible" to "poisonous." The researchers then diluted the chemicals so that their odors were equally intense. Finally, they created mixtures by dripping individual odorants onto separate regions of an absorptive pad in a jar, a technique that prevented the substances from reacting in liquid form to create new substances or odors. The odor blends contained anywhere from one to 43 of the chemicals, Sobel says. © 2010 American Association for the Advancement of Science

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 17510 - Posted: 11.20.2012

By Tia Ghose, LiveScience Humans can smell fear and disgust, and the emotions are contagious, according to a new study. The findings, published Nov. 5 in the journal Psychological Science, suggest that humans communicate via smell just like other animals. "These findings are contrary to the commonly accepted assumption that human communication runs exclusively via language or visual channels," write Gün Semin and colleagues from Utrecht University in the Netherlands. Most animals communicate using smell, but because humans lack the same odor-sensing organs, scientists thought we had long ago lost our ability to smell fear or other emotions. To find out, the team collected sweat from under the armpits of 10 men while they watched either frightening scenes from the horror movie "The Shining" or repulsive clips of MTV's "Jackass." Next, the researchers asked 36 women to take a visual test while they unknowingly inhaled the scent of men's sweat. When women sniffed "fear sweat," they opened their eyes wide in a scared expression, while those smelling sweat from disgusted men scrunched their faces into a repulsed grimace. (The team chose men as the sweat donors and women as the receivers because past research suggests women are more sensitive to men's scent than vice versa.) © 2012 NBCNews.com

Related chapters from BP7e: Chapter 15: Emotions, Aggression, and Stress; Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress; Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 17470 - Posted: 11.08.2012

by Joel Winston Never mind the bitter end – it is the bitter beginning of an infection that triggers an immune response. We know that taste receptors on the tongue can detect bitter foods, but it turns out that there are also identical taste receptors in the upper airway. Noam Cohen at the University of Pennsylvania in Philadelphia and his team think they know why. They grew cell cultures from sinus tissue samples collected from surgical patients, and found that bitter taste receptors in the tissue picked up the presence of Pseudomonas aeruginosa, a bacterium that can cause pneumonia. The sinus tissue responded by producing nitric oxide to kill the invading microbes. "Certain people have strong innate defences against these bacteria, which is based on their ability to detect bitterness," says Cohen. "Others who don't really 'taste' these bitter compounds have a weakened defence." The research could lead to nasal sprays designed to activate the taste receptors and boost people's natural defences against sinus infections. "This is probably the most exciting clinical link found for bitter receptors," says Liquan Huang of the Monell Chemical Senses Center in Philadelphia, Pennsylvania, who was not involved in the study. "However, further work is needed to see if this can be translated into treatments." Journal reference: Journal of Clinical Investigation, doi.org/jj4 © Copyright Reed Business Information Ltd.

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 17415 - Posted: 10.24.2012

By Christina Agapakis Smell is notoriously subjective and hard to define. Odors can be perceived differently by different people depending on genetics, culture, past experience, the environment, and whether they’ve had a really bad sinus infection or not. Even worse, the same person can perceive the same smell differently at different times, depending on how the smell is described and other sensory fluctuations. Leslie Vosshall’s Laboratory of Neurogenetics and Behavior at Rockefeller University studies how complex behaviors are influenced by the chemical senses in organisms ranging from mosquitoes to humans. In order to better understand how human odor perception varies, both within individuals at different times and between different people, the lab asked nearly 400 New Yorkers to describe and rate the intensity and pleasantness of 66 different smells, at the same time collecting demographic data (significantly more diverse than the typical study of undergraduate psychology students) as well as data about their eating habits and perfume usage, finding many instances of variability in how people perceive smells. The lab recently published their extensive survey titled “An olfactory demography of a diverse metropolitan population” in the open-access journal BMC Neuroscience. They’ve also made their data freely available (you can download the huge excel file here) for further analysis or data-mining. This study has been ongoing for several years, and two years ago inspired Nicola Twilley’s wonderful Scratch-and-Sniff Map of New York’s olfactory psychogeography. Rather than mapping what people smell, the odors that they would encounter in different neighborhoods, she mapped how they smell, mapping odor preferences by neighborhood using homemade scratch-and-sniff stickers, sampling some of the variation in our smell universe. © 2012 Scientific American

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 17404 - Posted: 10.22.2012

By HENRY FOUNTAIN SAINT-LOUIS, France — Denis Spitzer wants to beat dogs at their own game. At a binational armaments and security research center here in eastern France, Dr. Spitzer and his colleagues are working on a sensor to detect vapors of TNT and other explosives in very faint amounts, as might emanate from a bomb being smuggled through airport security. Using microscopic slivers of silicon covered with forests of even smaller tubes of titanium oxide, they aim to create a device that could supplement, perhaps even supplant, the best mobile bomb detector in the business: the sniffer dog. But emulating the nose and brain of a trained dog is a formidable task. A bomb-sniffing device must be extremely sensitive, able to develop a signal from a relative handful of molecules. And it must be highly selective, able to distinguish an explosive from the “noise” of other compounds. While researchers like Dr. Spitzer are making progress — and there are some vapor detectors on the market — when it comes to sensitivity and selectivity, dogs still reign supreme. “Dogs are awesome,” said Aimee Rose, a product sales director at the sensor manufacturer Flir Systems, which markets a line of explosives detectors called Fido. “They have by far the most developed ability to detect concealed threats,” she said. But dogs get distracted, cannot work around the clock and require expensive training and handling, Dr. Rose said, so there is a need for instruments. © 2012 The New York Times Company

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 17372 - Posted: 10.16.2012

By Meghan Rosen David Ferrero wasn’t expecting the jaguar to pounce. When he approached the holding pens at Massachusetts’ Stone Zoo, the big cat watched but looked relaxed, lounging on her cage’s concrete floor. Two other jaguars rested in separate cages nearby. The jaguars usually prowled outside, in the grassy grounds of the zoo’s enclosure. But this afternoon, zookeepers kept the animals inside so that Ferrero and a colleague could grab a behind-the-scenes peek. Here, the jaguars slept at night — and fed. Here, only metal bars stood between the humans and the cats. As Ferrero stepped closer to the cages, the watchful female sprang up, twisting her body toward him, front paws thumping the bars. Fully extended, she was as tall as Ferrero. “I think she wanted to eat me,” he says. The zookeepers weren’t afraid, but Ferrero flinched. He wasn’t familiar with the lean, black-spotted feline. He was just there to pick up some pee. Ferrero, a neurobiologist from Harvard, was visiting the zoo to gather urine specimens for a study linking odors to instinctual behavior in rodents. Early lab results had hinted that a whiff of a chemical in carnivore pee flashed a sort of billboard message, blinking “DANGER” in neon lights — enough to make animals automatically shrink away in fear. © Society for Science & the Public 2000 - 2012

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 17334 - Posted: 10.06.2012