Links for Keyword: Chemical Senses (Smell & Taste)

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By Jennifer Verdolin Typically we think of eavesdropping as a human endeavor. Individually we all do it to a certain degree. Call it social listening, if you will. Sometimes we can’t help but overhear a conversation. Other times we might deliberately try to listen in on what someone else is saying. I remember as a kid putting a cup up against the door to try and hear what was going on behind closed doors. Collectively as nations we eavesdrop on a massive scale, in times of peace and war. Currently, the military spends a considerable amount of money on ‘electronic intelligence’, so much so that there is an entire center devoted to eavesdropping: Menwith Hill in North Yorkshire. We certainly did not invent this strategy of watching or listening in on others. Like most things, we’ve copied it from nature. Eavesdropping is ubiquitous across the animal kingdom. Whenever substantial time or resources are devoted to an activity there is usually a payoff to be found. This got me wondering, what is the payoff for eavesdropping? Several advantages immediately come to mind. For example, perhaps you can increase your access to resources. One way to do this would be to avoid wasting time going after resources that someone else has already used up. This is frequently observed among competitors searching for similar resources. When one thinks of fierce competitors, two stingless bee species may not be the first thing that comes to mind. © 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: 16788 - Posted: 05.14.2012

By Erin Johnson As a woman scientist in the beginning of my career I’m always interested in the journey of more established female scientists: how their interest in science developed, how they’ve overcome challenges to be successful, and how they’ve balanced their goals of establishing a successful career with the desire to have a family. So when I had the opportunity to speak with and interview the Nobel Laureate Dr. Linda Buck during the Frontiers in the Life Sciences symposium, I was immediately intimidated but ultimately excited about speaking to someone who has obtained what many consider to be the most prestigious award in science. What I learned, however, is that Dr. Buck is extremely approachable and an ardent proponent for increasing the representation of women in the life sciences. Additionally, she is a passionate spokeswoman for basic research and gets her motivation and drive, which led to her notable successes, from a true passion for discovery. Dr. Linda Buck was born in Seattle, Washington where at an early age her parents instilled in her a “can-do” attitude, which she credits as a major factor in her road to success. “They taught me to think independently and to be critical of my own ideas, and they urged me to do something worthwhile with my life, to not settle for something mediocre,” says Dr. Buck. She never felt that as a woman she couldn’t achieve the things she set out to do. © 2012 Scientific American,

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 11: Emotions, Aggression, and Stress
Link ID: 16698 - Posted: 04.24.2012

By C. CLAIBORNE RAY Q. Are taste buds really divided into sections on the tongue that sense four different flavors? A. Trying to navigate the sense of taste with a map of the tongue labeled with regions sensitive to four kinds of flavor would be like trying to drive cross-country with a map that did not show the Interstate System. “Although there are subtle regional differences in sensitivity to different compounds over the lingual surface, the oft-quoted concept of a ‘tongue map’ defining distinct zones for sweet, bitter, salty and sour has largely been discredited,” according to a review article in The Journal of Cell Biology in August 2010. That map of relative sensitivities, frequently reproduced in textbooks after the researcher Edwin G. Boring sketched it in 1942, neglected the “fifth taste,” called umami, from the Japanese for rich, meaty protein flavors. The outdated map also did not reflect later findings that taste buds, clusters of sensitive cells, have different degrees of sensitivity to molecules carrying more than one basic taste and that these clusters are distributed across the entire surface of the tongue. Recognizing bitterness is thought to protect against bitter poisons; sweet tastes signal sugars and carbohydrates; salty tastes signal sodium compounds and other salts; and sour tastes indicate organic acids. The tongue may also have specialized receptors for fatty flavors, researchers say. © 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: 16544 - Posted: 03.20.2012

Ewen Callaway Many meat-eating animals have lost their ability to taste sugars over the course of evolution. Sea mammals, spotted hyenas and other carnivores have all shed a working copy of a gene that encodes a ‘taste receptor’ that senses sugars, finds a study published this week in the Proceedings of the National Academy of Sciences1. An animal with a diet devoid of vegetables may have little need to detect sugars, says Gary Beauchamp, director of the Monell Chemical Senses Center in Philadelphia, Pennsylvania, and the lead author of the study. He sees parallels with cave-dwelling fish that have lost their sense of sight. Most mammals, including humans, are equipped with taste receptors that detect salty, sour, sweet, bitter and savoury foods. But past studies suggest that some animals lack certain taste receptors. Felines such as house cats, tigers and cheetahs do not favour sugar water over plain water, for example, and they all possess an identical mutation in a gene called Tas1r2 that renders the sweet-taste receptor inactive2. To see whether other carnivores also lack sweet receptors, Beauchamp and his team collected DNA from 12 members of the order Carnivora, including spotted hyenas, a cat-like creature from Madagascar called a fossa, a civet called a banded linsang and several species of sea mammal. © 2012 Nature Publishing Group

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 16506 - Posted: 03.13.2012

by Vivien Marx Call it the fish version of instant messaging. When a fish is injured, it secretes a compound that makes other fish dart away (as seen in the latter half of the sped up video above, when the red light flashes). The substance, named Schreckstoff (German for "scary stuff"), protects the entire community of fish, but no one knew how it worked. Now they do, thanks to an analysis of fish mucus reported today in Current Biology. The key ingredient in Schreckstoff is a sugar called chondroitin sulfate, which is found in abundance in fish skin. When the skin is torn, enzymes break the compound down into sugar fragments that activate an unusual class of sensory neurons known as crypt cells in other fish. And the fish take off. © 2010 American Association for the Advancement of Science

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 11: Emotions, Aggression, and Stress
Link ID: 16429 - Posted: 02.25.2012

By Ferris Jabr There's a scene in Pixar's Finding Nemo when Dory, a yellow-finned regal tang, injures herself in a tug-of-war over a snorkel mask. A tiny plume of blood curls away from Dory's face into the water around her, where it is sucked into the nostrils of Bruce, a "vegetarian" shark who immediately recants his no-sushi policy. (Fortunately, Dory escapes.) Scientists have known for some time that many ocean predators relish the scent of an injured fish, whereas fish that are more likely to end up as a meal flee from the same scent. Now, researchers think they have pinpointed the key chemical in fish skin that warns nearby fish of danger—a chemical related to a supplement some people take for joint pain. In the 1930s Austrian animal behavior scientist Karl von Frisch accidentally injured a minnow in a tank. He noticed that the other fish in the tank began alternately darting back and forth and freezing in place—classic predator-evading behavior. Subsequent experiments established that the frightened fish were responding to chemicals released from the skin of their injured peer—a cocktail dubbed schreckstoff, which is German for "scary stuff." For decades, the chemistry of schreckstoff remained unknown. In the 1970s and '80s some scientists discovered that exposing fish to a chemical known as hypoxanthine-3-N-oxide (H3NO) frightened them in the same way as schreckstoff, albeit to a lesser degree. H3NO, they concluded, was probably the active compound in schreckstoff. But there was a problem with that idea: scientists had never reliably detected H3NO in fish skin. Instead, some researchers proposed, H3NO may mimic the genuine active compound. © 2012 Scientific American,

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 11: Emotions, Aggression, and Stress
Link ID: 16428 - Posted: 02.25.2012

By Victoria Gill Science reporter, BBC Nature Ant colonies - one of nature's most ancient and efficient societies - are able to form a "collective memory" of their enemies, say scientists. When one ant fights with an intruder from another colony it retains that enemy's odour: passing it on to the rest of the colony. This enables any of its nest-mates to identify an ant from the offending colony. The findings are reported in the journal Naturwissenschaften. For many ant species, chemicals are key to functioning as a society. Insects identify their nest-mates by the specific "chemical signature" that coats the body of every member of that nest. The insects are also able to sniff out any intruder that might be attempting to invade. This study, carried out by a team from the University of Melbourne in Australia, set out to discover if ants were able to retain memories of the odours they encounter. The researchers studied the tropical weaver ant (Oecophylla smaragdina), which builds is home in trees; one nest can contain up to 500,000 workers. The team set up a "familiarisation test" to allow ants from one nest to encounter intruders from another. BBC © 2012

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 11: Emotions, Aggression, and Stress
Link ID: 16413 - Posted: 02.23.2012

By Adam Hadhazy Love might be in the air on Valentine's Day, metaphorically speaking. But scientists have long debated whether love—or, at least, sexual attraction—is literally in the air, in the form of chemicals called pheromones. Creatures from mice to moths send out these chemical signals to entice mates. And if advertisements about pheromone-laden fragrances are to be believed, one might conclude that humans also exchange molecular come-hithers. Still, after decades of research, the story in humans is not quite so clear. Rather than positing that single, pheromone-esque compounds strike us like Cupid's arrow, investigators now suggest that a suite of chemicals emitted from our bodies subliminally sways potential partnerings. Smell, it seems, plays an underappreciated role in romance and other human affairs. "We've just started to understand that there is communication below the level of consciousness," says Bettina Pause, a psychologist at Heinrich Heine University of Düsseldorf (H.H.U.), who has been studying pheromones and human social olfaction for 15 years. "My guess is that a lot of our communication is influenced by chemosignals." Animals, plants and even bacteria produce pheromones. These precise cocktails of compounds trigger various reactions in fellow members of a species—not all of which are sexual. Pheromonal messages can range from the competitive, such as the "stink fights" of male lemurs, to the collaborative, such as ants laying down chemical trails to food sources. © 2012 Scientific American,

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: 16374 - Posted: 02.14.2012

Allie Bidwell, Chronicle Staff Writer For most of his adult life, Michael Berg has suffered from sinus problems that led to strange reactions to the way he smelled and tasted things. Drinking a glass of wine or smoking a cigar, for example, would drastically reduce his sense of smell. He knew that alcohol and smoking could dull the senses, so he thought nothing of it. Then one day in 2005, his sense of smell completely vanished. "Literally one day we were having dinner, and I remember I couldn't smell or taste anything," Berg, 55, said. Experts estimate that about 2 percent of the U.S. population suffers from Berg's condition, a lack of smell known as anosmia. And research by neuroscientists at UC Berkeley provides hope of new therapies for those who have lost their sense of smell, whether due to aging, trauma or a viral infection. In the study published this month in the journal Neuron, the researchers - led by campus neurobiology Professor John Ngai - found a genetic trigger responsible for renewing smell sensors in the nose. That gene, known as p63, tells olfactory stem cells whether to replace themselves or to change into different types of cells. Under normal circumstances, Ngai said, there is a balance between the two outcomes. © 2011 Hearst Communications Inc.

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 13: Memory, Learning, and Development
Link ID: 16189 - Posted: 12.27.2011

By Katherine Harmon Weakening eyesight can be sharpened with lenses, and impaired hearing can be improved with aids. What about a failing sense of smell? Detecting and distinguishing the floral bouquet of fresh honey or the miasma of bad lunchmeat might not seem quite as critical for day-to-day existence as sight or hearing. But what the nose knows is clearly important for quality of life. Research has linked this diminution, which is common in people over the age of 60 and can be exacerbated by smoking and some diseases, to loss of appetite and even to depression. Now sufferers might not have to give in to an odorless future, according to a new study, published online Sunday in Nature Neuroscience. Researchers at the New York University Langone Medical Center have found that, with some simple training, over time lab rats could actually improve their brain’s ability to distinguish smells. Without any practice rats could tell when one scent—in a mélange of 10—had been switched for another. (Researchers figured this out by waiting until the rodents were thirsty, then training them to look for water in one of a selection of holes based on what odor combination they had detected.) But their powers of discrimination were not perfect. If a scent was missing from the mix, the rats did not seem to be able to discern it from a full 10-scent combination. Other rats, however, were trained to become extra-familiar with the different combinations through repeated exposures and rewards. “We made them connoisseurs,” co-author Donald Wilson, a professor of psychiatry at NYU Langone, said in a prepared statement. © 2011 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: 16072 - Posted: 11.22.2011

By Rachel Ehrenberg Scientists have finally explained how a little red berry makes just about anything, from the sourest lemon to the bitterest beer, taste as sweet as honey. A protein found in the fruit tickles the tongue’s sweet-sensing machinery, its effects intensifying in the presence of acidic flavors like citrus and carbonated drinks. Researchers and foodies alike have long known the effects of the miracle fruit (a.k.a. Richadella dulcifica). At flavor-tripping parties, guests will pop a berry then chew, chew and chew some more, letting the masticated fruit linger on the tongue. Then the sampling begins: Guinness tastes like a chocolate shake, Tabasco loses its sting and pickles their mouth-pinching tang. Lemons and limes gush with sweetness. While the active ingredient in miracle fruit — miraculin — has been known for decades, it hasn’t been clear exactly how the protein confers its sweetness. Now scientists in Japan and France report that miraculin’s interaction with the tongue’s sweet sensors depends on the acidity of the local environment. At a pH of 4.8 (water is neutral with a pH close to 7), the sweet-tasting cells respond twice as vigorously to miraculin than they do at a less acidic pH of 5.7. At closer-to-neutral pH levels of 6.7 and higher, the protein seems to slightly shift shape, blocking the sweet sensors but not activating them. This explains why under certain conditions sweet foods may taste less flavorful after eating the berry, researchers led by Keiko Abe of the University of Tokyo report online September 26 in the Proceedings of the National Academy of Sciences. © Society for Science & the Public 2000 - 2011

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: 15853 - Posted: 09.29.2011

By Nick Bascom Even the inside of the nose can be a little cliquish. Like birds of a feather, nasal molecules that respond to pleasant smells flock together, keeping their distance from sensor molecules that pick up unpleasant smells. Sensor molecules, or receptors, appear to be organized according to the pleasantness (or unpleasantness) of the odors they sense, a new study finds. For example, locations in the nose that respond strongly to one fragrant aroma will respond strongly to other delectable smells. Patches of nasal surfaces that process putrid stenches also handle specific sorts of smells and leave the rest of the work to someone else, Noam Sobel of the Weizmann Institute of Science in Rehovot, Israel and colleagues reported online September 25 in Nature Neuroscience. The researchers inserted an electrode into 16 subjects’ noses and then showered the volunteers with six different scents. Because certain odors provoked stronger responses at different locations in the nose, the research team was able to confirm previous evidence suggesting a variegated nasal receptor surface. “We’re not the first to find that,” says Sobel. But he and his colleagues have added an important new wrinkle. “Not only are the receptors organized in patches, but the axis that best describes their organization is pleasantness.” This discovery sheds new light on a relatively poorly studied sensory organ. Compared with eyes or ears, scientists don’t know much about how the nose works. © Society for Science & the Public 2000 - 2011

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 11: Emotions, Aggression, and Stress
Link ID: 15837 - Posted: 09.26.2011

By Jennifer Welsh, LiveScience Staff Writer Cats arch their backs at the smell of a rival, and mice scurry at the scent of a fox. But how does the nose know who or what is lurking? Now scientists have identified several special receptors in the noses of animals that react to specific scents given off by others. It's these receptors that signal to the brain whether the animal needs to flee, make itself large and scary, or perhaps even woo a mate. "Animals in the wild need to be able to recognize other animals, whether they are predators, potential mates or rivals," study researcher Catherine Dulac of Harvard University told LiveScience. "Many animals rely on the sense of smell; they can distinguish one type of encounter from another one based on chemicals." Experimenting on mice, Dulac and her fellow researchers discovered that more of the animal's receptors seem to be dedicated to sniffing out predators than to detecting potential mates. When a cat or mouse senses the chemical compounds secreted by other animals, it activates a special sensor in the nose called the vomeronasal organ. This organ, which is found in many animals and consists of a set of receptors, sends a signal to the brain, which interprets the signal and takes action. (Though humans have lost this organ, research has suggested humans do react in various ways to chemical cues.) © 2011 LiveScience.com

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: 15836 - Posted: 09.26.2011

By Susan Milius Penguins may be able to smell some feathery, waddling whiff of kinship on others of their kind. In some sniff tests, Humboldt penguins (Spheniscus humboldti) in the Brookfield Zoo outside Chicago could discriminate between the odor of birds they knew and birds they weren’t familiar with, says Jill Mateo of the University of Chicago. More intriguingly, the birds also showed evidence of an ability to distinguish between the scents of relatives and nonrelatives even if they weren’t personally familiar with the scent owners, Mateo and her colleagues report September 21 in PLoS ONE. The ability to recognize kin by smell has shown up in many other kinds of animals, including mammals, amphibians and fish. Although the new study is limited by its small size, it could be the first to show odor-based kinship recognition among birds. New evidence that a sense of smell may be important in birds also makes the study intriguing. For decades, scientists thought that most species of birds responded minimally, if at all, to odor cues. In recent years, though, researchers have uncovered more and more evidence for functionally significant sniffing, such as the odor detection of food out in the open ocean by blue petrels and some other tubenose seabirds. Odor-based kin recognition would make sense for colony-dwelling birds with lifetime monogamy such as the Humboldt penguins, which return to the same rookeries where they hatched in search of mating prospects. Birds hatched in different years by same parents could easily meet, Mateo says. “If familiarity is the only mechanism available to them, they might say, ‘Hey, I’m not related to you. Let’s have sex.” So a sniff test for kinship could come in handy. © Society for Science & the Public 2000 - 2011

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: 15830 - Posted: 09.24.2011

by Catherine de Lange I TRY to forget about potential onlookers as I crawl around a central London park, blindfolded and on all fours. With a bit of luck, the casual passer-by might not notice the blindfold and think I'm just looking for a contact lens. In fact, I'm putting my sense of smell to the test, and attempting to emulate the sensory skills of a sniffer dog. Just as a beagle can swiftly hunt down a pheasant using only its nasal organ, I am using mine to follow a 10-metre trail of cinnamon oil. Such a challenge might sound doomed to failure. After all, dog noses are renowned for their sensitivity to smells, while human noses are poor by comparison. Yet that might be a misconception. According to a spate of recent studies, our noses are in fact exquisitely sensitive instruments that guide our everyday life to a surprising extent. Subtle smells can change your mood, behaviour and the choices you make, often without you even realising it. Our own scents, meanwhile, flag up emotional states such as fear or sadness to those around us. The big mystery is why we aren't aware of our nasal activity for more of the time. Noses have certainly never been at the forefront of sensory research, and were pushed aside until recently in favour of the seemingly more vital senses of vision and hearing. "There has been a lot of prejudice that people are not that influenced by olfactory stimuli, especially compared to other mammals," says Lilianne Mujica-Parodi, who studies the neurobiology of human stress at Stony Brook University in New York. © Copyright Reed Business Information Ltd.

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 11: Emotions, Aggression, and Stress
Link ID: 15821 - Posted: 09.20.2011

While the tongue map may have been thoroughly debunked, what about our brains? Does each kind of flavor get processed in its own little corner of our grey matter? According to new research, they just might. The image above is of the taste cortex (insula) of a mouse, with each of the color clumps representing one of four of the five primary tastes. Red is bitter, green is sweet, yellow is umami, and orange is salt. While the researchers also tested sour foods, they didn't spot a sour cluster, either because it was elsewhere in the brain or because sour food can also mess with pain pathways in the brain, as well as taste. What's interesting is how densely packed these taste hot spots are. Apparently, very few flavors cross over from one region to the other. In case you're curious what foods the researchers used as perfect examples of each taste type, they were: quinine and cycloheximide for bitter, sucrose and acesulfame potassium for sweet, MSG for umami, NaCl for salty and citric acid for sour. So, how long before we start hacking our brains to taste completely new flavors?

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: 15764 - Posted: 09.06.2011

by Caroline Williams Ever wondered how a dog, with a sense of smell that may be thousands of times more sensitive than ours, can bear to bury its face in the trash can? Alexandra Horowitz, a dog-cognition researcher at Columbia University in New York City and author of Inside of a Dog: What dogs see, smell, and know, says it's because the dog isn't simply smelling a stronger version of the revolting mono-stench that we smell. "It is not that smells are 'louder'," she says. "The smells have different layers, which probably give dogs a much bigger range of types of information." She compares it to the way we might enjoy a painting from across the room, but appreciate it in a different way when we can get up close and see the brush strokes. This makes a dog's experience fundamentally different to our own. When we go out for a walk, for example, we get almost all of our information from vision. But the dog's eyes are just a back-up. This was shown when police tracker dogs were given a scent trail that seemed to run in the opposite direction to a set of footprints on the ground; they invariably followed their noses and ignored the contradictory visual cues (Applied Animal Behaviour Science, vol 84, p 297). This reliance on smell explains why a dog that isn't expecting to see its owner will often stop a metre or so away for a quick sniff before jumping all over them. To imagine the scent-based world of a dog, says Horowitz, look around and imagine that everything you see has its own individual scent. And not just each object - different parts of the same object may hold different types of information. Horowitz gives the example of a rose: each petal might have a different scent, telling the dog it has been visited by different insects that left telltale traces of pollen from other flowers. Besides picking up on the individual scent of humans that had touched the flower, it could even guess when they may have passed by. © 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: 15721 - Posted: 08.25.2011

MacGregor Campbell, consultant Want to get rid of destructive lampreys? In this video, you can see how the smell of death can be a particularly effective repellant. Michael Wagner of Michigan State University exposed a group of lampreys to a mixture of chemicals from putrefying carcasses and ethanol. Another group was subjected to a similar amount of plain ethanol as a control. The animals exposed to the death-scented chemicals jumped out of the tank with a panic-like response. Sea lampreys are an invasive species in the US Great Lakes. They live as parasites on the bodies of lake trout and other commercially-important fish and have contributed to collapsing fish stocks in the region. Currently, wildlife officials use pheromones to lure lampreys into large cages where they can be destroyed or sterilised. These are the same chemicals the lampreys rely on to attract mates or to find good spawning grounds. But using natural cues to attract lampreys can be inefficient since a variety of scents in natural waterways compete for their attention. According to Wagner, repellants could be a better alternative to divert them since even tiny quantities can provoke a response. The smell of death could be used to form a chemical dam to steer lampreys away from environmentally-sensitive waterways. The chemicals could also be used to corral the animals into groups, making them easier to eliminate. © 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: 15719 - Posted: 08.25.2011

By Laura Sanders A common virus may slink into the brain through the nose. After setting up shop in people’s nasal mucus, human herpesvirus-6 may travel along olfactory cells right into the brain, researchers report online the week of August 8 in the Proceedings of the National Academy of Sciences. Most people’s first bout with HHV-6 comes at a tender age: It causes the common childhood infection roseola, marked by a chest rash and a high fever. “Everyone is exposed to this,” says study coauthor Steven Jacobson of the National Institute of Neurological Disorders and Stroke in Bethesda, Md. “You have it. I have it.” Despite its ubiquity, very little is known about the virus. HHV-6 may live in tonsils and shed in saliva, some studies suggest. And in some people (researchers don’t know how many), the virus can infect the brain, where some researchers believe it may contribute to neurological disorders such as multiple sclerosis, encephalitis and a form of epilepsy. Other viruses such as herpes simplex, influenza A and rabies can invade the brain by shooting through the nose, so Jacobson and his team wondered whether HHV-6 could do the same trick. The researchers found high levels of HHV-6 in the olfactory bulb, a smell-related part of the brain, in two of three autopsy brain samples. The team then looked at nose mucus and found the virus in 52 of 126 different samples. “We were surprised to find so much in the nasal mucus,” Jacobson says. © Society for Science & the Public 2000 - 2011

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell; Chapter 2: Functional Neuroanatomy: The Nervous System and Behavior
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 2: Cells and Structures: The Anatomy of the Nervous System
Link ID: 15658 - Posted: 08.09.2011

By Karen Weintraub Out for a run six years ago, Molly Birnbaum was struck by a car. Recovering from surgeries to repair a broken pelvis and torn tendons, she realized the blow had also left her completely unable to smell. Then a recent college graduate and aspiring chef, Birnbaum said it was as if all the color drained out of life. Without the scent of roses, fresh bread, a spring rain, or even trash, she felt like she was living in a black and white world. Estimates are that 1-2 percent of Americans under 65 have a limited sense of smell; that percentage rises to as high as 50 percent of those over 65. And doctors are just beginning to realize how important smell is to our well-being and our perceptions of the world. “Your nose, sitting there in the middle of your face, is arguably the best chemical detector on the planet, but we usually fail to realize its importance until it goes missing due to illness or injury,’’ said Stuart Firestein, a scientist who studies the sense of smell, and the chairman of the biological sciences department at Columbia University. Research into the olfactory process has increased dramatically in recent years, with the first smell-related Nobel Prize awarded in 2004, to an American team; the discovery that smell plays a role in some brain disorders; and the hope that a better understanding of smell may offer insights into how the brain works. © 2011 NY Times Co.

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: 15576 - Posted: 07.19.2011