Links for Keyword: Chemical Senses (Smell & Taste)

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Alva Noë Eaters and cooks know that flavor, in the jargon of neuroscientists, is multi-modal. Taste is all important, to be sure. But so is the look of food and its feel in the mouth — not to mention its odor and the noisy crunch, or juicy squelch, that it may or may not make as we bite into it. The perception of flavor demands that we exercise a suite of not only gustatory, but also visual, olfactory, tactile and auditory sensitivities. Neuroscientists are now beginning to grasp some of the ways the brain enables our impressive perceptual power when it comes to food. Traditionally, scientists represent the brain's sensory function in a map where distinct cortical areas are thought of as serving the different senses. But it is increasingly appreciated that brain activity can't quite be segregated in this way. Cells in visual cortex may be activated by tactile stimuli. This is the case, for example, when Braille readers use their fingers to read. These blind readers aren't seeing with their fingers, rather, they are deploying their visual brains to perceive with their hands. And, in a famous series of studies that had a great influence on my thinking on these matters, Miriganka Sur at MIT showed that animals whose retinas were re-wired surgically to feed directly into auditory cortex do not hear lights and other visible objects presented to the eyes, rather, they see with their auditory brains. The brain is plastic, and different sensory modalities compete continuously for control over populations of cells. An exciting new paper on the gustatory cortex from the laboratory of Alfredo Fontanini at Stony Brook University shows that there are visual-, auditory-, olfactory- and touch-sensitive cells in the gustatory cortex of rats. There are even some cells that respond to stimuli in more than one modality. But what is more remarkable is that when rats learn to associate non-taste qualities — tones, flashes of lights, etc. — with food (sucrose in their study), there is a marked transformation in the gustatory cortex. © 2016 npr

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell; Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 7: Vision: From Eye to Brain
Link ID: 22675 - Posted: 09.21.2016

By Jessica Hamzelou As any weight-watcher knows, carb cravings can be hard to resist. Now there’s evidence that carbohydrate-rich foods may elicit a unique taste too, suggesting that “starchy” could be a flavour in its own right. It has long been thought that our tongues register a small number of primary tastes: salty, sweet, sour and bitter. Umami – the savoury taste often associated with monosodium glutamate – was added to this list seven years ago, but there’s been no change since then. However, this list misses a major component of our diets, says Juyun Lim at Oregon State University in Corvallis. “Every culture has a major source of complex carbohydrate. The idea that we can’t taste what we’re eating doesn’t make sense,” she says. Complex carbohydrates such as starch are made of chains of sugar molecules and are an important source of energy in our diets. However, food scientists have tended to ignore the idea that we might be able to specifically taste them, says Lim. Because enzymes in our saliva break starch down into shorter chains and simple sugars, many have assumed we detect starch by tasting these sweet molecules. Her team tested this by giving a range of different carbohydrate solutions to volunteers – who it turned out were able to detect a starch-like taste in solutions that contained long or shorter carbohydrate chains. “They called the taste ‘starchy’,” says Lim. “Asians would say it was rice-like, while Caucasians described it as bread-like or pasta-like. It’s like eating flour.” © Copyright Reed Business Information Ltd.

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell; Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 22639 - Posted: 09.10.2016

By Alison F. Takemura A stationary Carolina sphinx moth (Manduca sexta) is the Cinderella of the animal kingdom. The hummingbird-size insect has dull, dark wings that are mottled like charred wood, and a plump body reminiscent of a small breakfast sausage. Casual observers of M. sexta often see little else. “They say, ‘Oh, it doesn’t look so nice. It’s just grey.’ But as soon as [the moths] start flying, they’re completely impressed,” says Danny Kessler, a pollination ecologist at the Max Planck Institute of Chemical Ecology in Germany. “They change their minds completely.” Hawkmoths, the group to which M. sexta belongs, whir their wings like hummingbirds as they flit between flowers, hovering to drink nectar. M. sexta’s proboscis, longer than its 2-inch body, stays unfurled, a straw ready to sip. Kessler studies the interaction between the Carolina sphinx moth, whose larvae are known as tobacco hornworms, and its preferred food source, the coyote tobacco plant (Nicotiana attenuata), to better understand how insect behavior affects a plant’s reproductive success. M. sexta adults drink nectar from tobacco’s skinny, white, trumpet-shape flowers, foraging from them at night and pollinating them in the process. Scientists have known for decades that the moth uses its antennae to detect the flowers’ scent—even from several miles away, Kessler says. © 1986-2016 The Scientist

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: 22626 - Posted: 09.05.2016

By Simon Oxenham It can seem like barely a week goes by without a new study linking the stage in a woman’s monthly cycle to her preferences in a sexual partner. Reportedly, when women are ovulating they are attracted to men who are healthier, more dominant, more masculine, have higher testosterone levels– the list goes on. But do women really exhibit such behavioural changes – and why are we so fascinated by the idea that they do? A popular theory in evolutionary psychology is that women seek out men with better genes while they are ovulating to have short term affairs with, so as to produce healthier babies. These men may not necessarily stick around for the long haul, but appear particularly attractive when a woman is in the fertile stage of her cycle. During the non-fertile phase, the theory goes that women seek out men who are more likely to make reliable long-term partners and good fathers. But something smells a bit fishy here. Are women really evolutionarily hard-wired to cuckold their partners? Or might the attraction of a salacious hypothesis – with slightly sexist overtones – be shaping some of this research? Masculine all month A review of these kinds of studies is now challenging this often-told story. Wendy Wood at the University of Southern California and her team have analysed 58 studies – some of which were never published – and found that this theory is largely unsupported by evidence. © Copyright Reed Business Information Ltd.

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: 22611 - Posted: 08.30.2016

By Michael Price Doctors and soldiers could soon place their trust in an unusual ally: the mouse. Scientists have genetically engineered mice to be ultrasensitive to specific smells, paving the way for animals that are “tuned” to sniff out land mines or chemical signatures of diseases like Parkinson’s and Alzheimer’s. Trained rats and dogs have long been used to detect the telltale smell of TNT in land mines, and research suggests that dogs can smell the trace chemical signals of low blood sugar or certain types of cancer. Mice also have powerful sniffers: They sport about 1200 genes dedicated to odorant receptors, cellular sensors that react to a scent’s chemical signature. That’s a few hundred less than rats and about the same as dogs. (Humans have a paltry 350.) Paul Feinstein wants to upgrade the mouse’s already sensitive nose. For the last decade, the neurobiologist at Hunter College in New York City has been studying how odorant receptors form on the surface of neurons within the olfactory system. During development, each olfactory neuron specializes to express a single odorant receptor, which binds to chemicals in the air to detect a specific odor. In other words, each olfactory neuron has a singular receptor that senses a particular smell. Normally, there is an even distribution of receptors throughout the system, so each receptor can be found in about 0.1% of mouse neurons. Feinstein wondered if he could make the mouse’s nose pay more attention to particular scents by making certain odorant receptors more numerous. He and colleagues developed a string of DNA that, when injected into the nucleus of a fertilized mouse egg, appears to make olfactory neurons more likely to develop one particular odorant receptor than the others. This receptor, called M71, detects acetophenone, a chemical that smells like jasmine. When the team added four or more copies of the DNA sequence to a mouse egg, a full 1% of neurons carried it—10 times more than normal. © 2016 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: 22412 - Posted: 07.08.2016

By Patrick Monahan Birds are perhaps best known for their bright colors, aerial prowess, and melodic songs. But research presented in Austin last week at the Evolution Conference shows that bacteria have granted some birds another important attribute: stink. Having long taken a back seat to sight and sound, scent is becoming more and more recognized as an important sense for songbirds, and dark-eyed juncos (Junco hyemalis, pictured) are no stranger to it. When these common birds clean their feathers—or preen—they spread pungent oil from their “preen glands” all over their bodies. The act is important for enticing mates: Three of the gland’s smelly chemicals are found in very different quantities in the two sexes, and males with a more masculine musk end up with more offspring. Females with a more feminine scent profile are more successful, too. But juncos likely aren’t making their perfume alone: Lots of those preen gland chemicals are naturally made by bacteria. And new work is making the bird-bacteria link even more firm. When researchers inject antibiotics into the juncos’ preen glands, the concentrations of three smelly molecules tend to decrease—the same three molecules that juncos find sexy in the right proportions, Danielle Whittaker of Michigan State University in East Lansing told attendees. So it seems like juncos may actually be picking mates based on their bacterial—rather than self-produced—body odor, a first for birds. © 2016 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: 22377 - Posted: 06.30.2016

By REUTERS SINGAPORE — Phones or watches may be smart enough to detect sound, light, motion, touch, direction, acceleration and even the weather, but they can't smell. That's created a technology bottleneck that companies have spent more than a decade trying to fill. Most have failed. A powerful portable electronic nose, says Redg Snodgrass, a venture capitalist funding hardware start-ups, would open up new horizons for health, food, personal hygiene and even security. Imagine, he says, being able to analyze what someone has eaten or drunk based on the chemicals they emit; detect disease early via an app; or smell the fear in a potential terrorist. "Smell," he says, "is an important piece" of the puzzle. It's not through lack of trying. Aborted projects and failed companies litter the aroma-sensing landscape. But that's not stopping newcomers from trying. Like Tristan Rousselle's Grenoble-based Aryballe Technologies, which recently showed off a prototype of NeOse, a hand-held device he says will initially detect up to 50 common odors. "It's a risky project. There are simpler things to do in life," he says candidly. The problem, says David Edwards, a chemical engineer at Harvard University, is that unlike light and sound, scent is not energy, but mass. "It's a very different kind of signal," he says. That means each smell requires a different kind of sensor, making devices bulky and limited in what they can do. The aroma of coffee, for example, consists of more than 600 components. France's Alpha MOS was first to build electronic noses for limited industrial use, but its foray into developing a smaller model that would do more has run aground. Within a year of unveiling a prototype for a device that would allow smartphones to detect and analyze smells, the website of its U.S.-based arm Boyd Sense has gone dark. Neither company responded to emails requesting comment. © 2016 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: 22354 - Posted: 06.24.2016

By C. CLAIBORNE RAY Insects have an odor-sensing system that is roughly analogous to that of vertebrates, according to “The Neurobiology of Olfaction,” a survey published in 2010. Different species have varying numbers of odor receptors, special molecules that are attuned to specific odor molecules. Genes govern the production of each kind of receptor; the more genes, the more kinds of receptor. A big difference with insects is that their olfactory receptors are basically external, often within hairlike groups of cells, called sensilla, on the antennas, not inside a collection organ like a nose. Sign Up for the Science Times Newsletter Every week, we'll bring you stories that capture the wonders of the human body, nature and the cosmos. The odorant molecules encounter odorant-binding proteins, assumed to guide them to the long receptor nerve cells, called axons. Electrical signals are sent along the axons. The axons are usually connected to specific processing centers in the brain called glomeruli, held in a region called the antennal lobe. There the signals are analyzed. Depending on the nature, quantity and timing of the odor signals received, still other cells appear to excite or inhibit reactions. Exactly how the reaction system works is not yet fully understood. The Florida carpenter ant and the Indian jumping ant both have wide-ranging abilities to sense odors, with more than 400 genes to make different odor receptors, a 2012 study found. The fruit fly has only 61. The research also found marked differences in the smelling ability of the sexes, with the female ants well ahead. © 2016 The New York Times Company

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: 22316 - Posted: 06.14.2016

“I understand how the appearance and texture of food can change the experience,” says food writer and Great British Bake Off finalist Tamal Ray, “but I never really considered how the other senses might have a role to play.” An anaesthetist by day, Ray is best-known for creating spectacular tiered cakes and using a syringe to inject extra, syrupy deliciousness into them. Which is why we introduced him to Oxford psychologist Charles Spence and chef Jozef Youssef – and turned what they taught him about the science of taste into the video above. Part mad professor, part bon vivant, Spence has spent the past 15 years discovering that little of how we experience flavour is to do with our taste buds – smell, vision, touch and even sound dictate how we perceive flavours. Youssef, meanwhile, sharpened his culinary skills at the Fat Duck, the Connaught and the Dorchester, before starting experimental dining outfit Kitchen Theory, where he applies science to meals that play with the multisensory experience of eating. When Spence started studying the sensory science behind flavour perception, it was a deeply unfashionable subject. “There’s some ancient Roman notion that eating and drinking involve lower senses,” he says, “not higher, rational senses like hearing and vision.” Now, the fruits of the research field he calls “gastrophysics” can be seen everywhere from the world’s top restaurants to airline food, via progressive hospital kitchens and multisensory cocktail bars. Spence heads the Crossmodal Research Laboratory at the University of Oxford. “Crossmodal”, in this context, means the investigation of how all the senses interact. Although we’re often unaware of it, when it comes to flavour perception, we all have synaesthesia. That is, our senses intermingle so that our brains combine shapes, textures, colours and even sounds with corresponding tastes.

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: 22239 - Posted: 05.23.2016

By C. CLAIBORNE RAY Q. Why do we become desensitized to a perfume we are wearing while others can still smell it? A. Ceasing to smell one’s perfume after continuous exposure while casual passers-by can still smell it is just one example of a phenomenon called olfactory adaptation or odor fatigue. After some time without exposure, sensitivity is usually restored. A similar weakening of odor signals with continued exposure also takes place in animals other than humans, and researchers often rely on animal studies to try to understand the cellular and molecular bases for the condition. It has been suggested that odor fatigue is useful because it enables animals to sort out the signals of a new odor from the background noise of continuous odors. It may also enable them to sense when an odor grows stronger. Studies published in the journal Science in 2002 pinpointed a chemical that seems to act as a gatekeeper for neurons involved in smell, opening and closing their electric signal channels. Genetically engineered mice that did not produce the substance, a protein called CNGA4, had profoundly impaired olfactory adaptation. A separate test-tube study found similar changes on a cellular level, with the signal channels remaining open when CNGA4 was absent. question@nytimes.com © 2016 The New York Times Company

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell; Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 5: The Sensorimotor System
Link ID: 22042 - Posted: 03.29.2016

By RACHEL NUWER For all the havoc that zebra mussels, Asian carp, round gobies and dozens of other alien species have wrought on the Great Lakes, those waters have never known a foe like the sea lamprey. The vampirelike parasites cost many millions each year in depleted fisheries and eradication efforts. Wildlife managers have long used lampricide — the lamprey version of pesticide — with mixed results. Now, an innovative control program seeks to improve on that method by using pheromones to trick the bloodsuckers into voluntarily corralling themselves in designated areas, to then be trapped or poisoned. But achieving this depends on cracking the fish’s olfactory language. “The broad goal is to understand how this animal makes decisions,” said Michael Wagner, a fish ecologist at Michigan State University. “Then, we want to use that understanding to guide lampreys’ movements by manipulating the landscape of fear and opportunity.” Lampreys look like the stuff of horror films: a slithering, tubular body topped with a suction-cup mouth ringed with row upon row of hooked yellow teeth. With this mouth, a sea lamprey anchors to its fish prey and uses its rasping tongue to drill into the victim’s flesh. It remains there for up to a month, feeding on blood and body fluids. Even if a fish survives the attack, the gaping wound left behind often results in death. In their natural ranges, lampreys are important components of food webs. The problems begin only when they shift from native to invader. Sea lampreys slipped into Lake Ontario through the Erie Canal in the mid-19th century, and then made it past Niagara Falls around 1919 with the renovation of the Welland Canal. In the lakes, lampreys found a utopia: no predators, and bountiful prey that had no natural defenses against their voracious appetites. Biological disaster ensued. © 2016 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: 21869 - Posted: 02.08.2016

by Bethany Brookshire Unless you’re in the middle of biting into a delicious Reuben sandwich, you might forget that taste is one of the fundamental senses. “It’s required for our enjoyment of food,” explains Emily Liman, a taste researcher at the University of Southern California in Los Angeles. “Without taste … people stop eating. They don’t enjoy their food.” A life without the sweet jolt of sugar or the savory delights of umami seems, well, tasteless. When you put that mouthwatering combination of corned beef, Swiss cheese, Thousand Island dressing, sauerkraut and rye in your mouth, the chemicals in the sandwich stimulate taste buds on your tongue and soft palate. Those taste buds connect to the ends of nerve fibers extending delicately into the mouth. Those nerve fibers are the ends of cells located in the geniculate ganglion, a ball of cells nestled up against the ear canal on the side of your head. From there, taste sensations head toward the brain. Chemical messengers bridge the gap between the taste bud and the end of the nerve fiber. But what chemical is involved depends on the type of cell within the bud. There are three types of taste cells (imaginatively titled I, II and III). Type I is not well-understood, but it may be a kind of support cell for other taste cells. Type II, in contrast, is better known. These taste cells sense the slight bitterness of the rye seeds, the sweet edge of the Thousand Island dressing and the savory umami of the beef. They pass that delightful message on using the chemical ATP. © Society for Science & the Public 2000 - 2016

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell; Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 12: Psychopathology: The Biology of Behavioral Disorders
Link ID: 21823 - Posted: 01.26.2016

By Kerry Klein With their suction cup mouths filled with concentric circles of pointy teeth that suck the body fluid of unsuspecting victims, lampreys may seem like the stuff of horror movies. And indeed the 50-centimeter-long, eellike creatures can wreak havoc on freshwater communities when they invade from the sea, with a single sea lamprey able to kill 18 kilograms of fish in its lifetime. Now, the U.S. government has approved of a new way to combat these fearsome fish by using their own sense of smell against them. Sea lampreys are a particular problem in the Great Lakes regions of the United States and Canada. They hitchhiked into the region more than a century ago, likely attaching themselves to ships or fish that traveled along shipping channels from the Atlantic Ocean. Although most lampreys are mere parasites in their native habitats, those in the Great Lakes are far worse, says Nicholas Johnson, a research ecologist at the U.S. Geological Survey’s Hammond Bay Biological Station on Lake Huron in Millersburg, Michigan. “They kill their host, they get too big, they eat too much,” he says. “They’re really more of a predator.” After the toothy invaders proliferated in the mid-20th century, ecosystems all but collapsed, taking prosperous fishing and tourism industries with them. “It’s fair to say that lamprey[s] changed the way of life in the region,” says Marc Gaden of the Great Lakes Fishery Commission, a joint U.S. and Canadian organization based in Ann Arbor, Michigan, that’s tasked with managing the rebounding ecosystems. “Just about every fishery management decision that we make to this day has to take lamprey into consideration.” © 2016 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: 21808 - Posted: 01.21.2016

by Helen Thompson Earth’s magnetic field guides shark movement in the open ocean, but scientists had always suspected that sharks might also get their directions from an array of other factors, including smell. To sniff out smell’s role, biologists clogged the noses of leopard sharks (Triakis semifasciata), a Pacific coastal species that makes foraging trips out to deeper waters. Researchers released the sharks out at sea and tracked their path back to the California coast over four hours. Sharks with an impaired sense of smell only made it 37.2 percent of the way back to shore, while unimpaired sharks made it 62.6 percent of the way back to shore. The study provides the first experimental evidence that smell influences a shark’s sense of direction, the team writes January 6 in PLOS ONE. The animals may be picking up on chemical gradients produced by food sources that live on the coast. © Society for Science & the Public 2000 - 2015.

Related chapters from BP7e: Chapter 1: Biological Psychology: Scope and Outlook
Related chapters from MM:Chapter 1: An Introduction to Brain and Behavior
Link ID: 21753 - Posted: 01.07.2016

By Christopher Intagliata Back in ancient times, philosophers like Aristotle were already speculating about the origins of taste, and how the tongue sensed elemental tastes like sweet, bitter, salty and sour. "What we discovered just a few years ago is that there are regions of the brain—regions of the cortex—where particular fields of neurons represent these different tastes again, so there's a sweet field, a bitter field, a salty field, etcetera." Nick Ryba [pron. Reba], a sensory neuroscientist at the National Institutes of Health. Ryba and his colleagues found that you can actually taste without a tongue at all, simply by stimulating the "taste" part of the brain—the insular cortex. They ran the experiment in mice with a special sort of brain implant—a fiber-optic cable that turns neurons on with a pulse of laser light. And by switching on the "bitter" sensing part of the brain, they were able to make mice pucker up, as if they were tasting something bitter—even though absolutely nothing bitter was touching the tongues of the mice. In another experiment, the researchers fed the mice a bitter flavoring on their tongues—but then made it more palatable by switching on the "sweet" zone of the brain. "What we were doing here was adding the sweetness, but only adding it in the brain, not in what we were giving to the mouse." Think adding sugar to your coffee—but doing it only in your mind. The findings appear in the journal Nature. © 2015 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: 21648 - Posted: 11.20.2015

Rachel England Brussels sprouts, Marmite, stinky cheese … these are all foods guaranteed to create divisions around the dinner table –and sometimes extreme reactions. A friend once ordered a baked camembert at dinner and I had to physically remove myself from the vicinity, such was its overpowering stench. Yet foods that once turned my stomach – mushrooms and prawns, in particular – now make a regular appearance on my plate. How is it that my opinion of a juicy grilled mushroom has gone from yuk to yum after 30 years of steadfast objection? And why is it that certain foods leave some diners gagging theatrically while others tuck in with vigour? Taste is a complicated business. In evolutionary terms we’re programmed to prefer sweeter flavours to bitter tastes: sweet ripe fruits provide a good source of nutrients and energy, for example, while bitter flavours can be found in dangerous plant toxins, which we’re better off avoiding. We’re also more likely to go for fatty foods with a high calorie count which would provide the energy needed for hunting our next meal. But now we live in a world where bitter vegetables such as kale reign supreme, kids salivate over eye-wateringly sour sweets and hunting dinner is as strenuous as picking up the phone. There are some environmental factors at play. When you eat something, molecules in the food hit your taste cells in such a way as to send a message to your brain causing one of five sensations: sweetness, saltiness, bitterness, sourness or umami (a loanword from Japanese meaning ‘pleasant savoury taste’). Mix up these taste cells and messages with external influences and the results can be dramatic. © 2015 Guardian News and Media Limited

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: 21628 - Posted: 11.12.2015

Your sense of smell might be more important than you think. It could indicate how well your immune system is functioning, a study in mice suggests. Evidence of a connection between the immune system and the olfactory system – used for sense of smell – has been building for some time. For instance, women seem to prefer the scent of men with different immune system genes to their own. Meanwhile, other studies have hinted that the robustness of your immune system may influence how extraverted you are. To investigate further, Fulvio D’Acquisto at Queen Mary University of London and his colleagues studied mice missing a recombinant activating gene (RAG), which controls the development of immune cells. Without it, mice lack a working immune system and some genes are expressed differently, including those involved in the olfactory system. “That rang bells, because people with immune deficiencies often lose their sense of smell,” says D’Acquisto. Systemic lupus erythematosus, an autoimmune disease in which the immune system mistakenly attacks tissues in the skin, joints, kidneys, brain, and other organs, is one such example. His team measured how long it took mice to find chocolate chip cookies buried in their cages. Those missing RAG took five times as long as normal mice. They also failed to respond to the scent of almond or banana, which mice usually find very appealing – although they did still react to the scent of other mice. Further study uncovered abnormalities in the lining of their noses; physical evidence that their sense of smell might be disrupted. © 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: 21599 - Posted: 11.04.2015

By WILLIAM GRIMES The first show at the Museum of Food and Drink’s new space in Brooklyn is “Flavor: Making It and Faking It,” and it wastes no time in getting to the point. “What makes your favorite food so delicious?” the text on a large free-standing panel near the entrance asks. The one-word answer: “Chemicals.” The word is deflating. It’s a little like being told that the human soul has a specific atomic weight. Chemicals? Yuck. But maybe not. Flavors come in two varieties, natural and artificial, but what do the words really mean? This is the looming question in an exhibition about food and culture that opens next Wednesday, in a museum that until now has been a free-floating idea rather than a building with an address. The show follows the history of lab-created flavors from the middle of the 19th century, when German scientists created artificial vanilla, to the present day, when the culinary spin doctors known as flavorists tweak and blend the myriad tastes found in virtually every food product on supermarket shelves. Flavor is a complex, beguiling subject. At one of several “smell machines” throughout the exhibition, where specific aromas are emitted through silver hoses at the push of a button, visitors learn that coffee gets a little lift — the je ne sais quoi that makes it irresistible in the morning — from a sulfur compound also found in skunk spray. Tiny edible pellets distributed from gumball machines send the message in tactile form. This is an exhibition that is not just hands-on, but tongue-on and nostrils-on. © 2015 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: 21536 - Posted: 10.21.2015

The invaders put on a disguise and infiltrate the nest with dark plans: to kill the queen and enslave the kingdom. Usually when ants take pupae from other colonies as future slaves all hell breaks loose in ensuing battles. The enslaved individuals sometimes even strike back against their overlords. It’s a relatively dramatic affair, usually resulting in the aggressive slave-makers carrying the pupae back to their own colony, says Terrence McGlynn at California State University. But a species of ant found in the eastern US, Temnothorax pilagens, does things differently. It is the first ant species known to waltz into a colony and enslave others without killing, and one of a few that take not only pupae but adult workers, too. “This was extremely surprising as ants are usually able to detect foreign species or even individuals from a different colony through their chemical profile and react aggressively towards them,” says Isabelle Kleeberg at Johannes Gutenberg-Universität Mainz, Germany, whose team has found how they get away with it. Kleeberg tracked the behaviour of T. pilagens and their preferred slave species, Temnothorax ambiguus, in 43 raiding experiments using colour-marked individuals. In each experiment the colonies of these two ant species, each housed in a plastic box, were placed 12 centimetres apart from each other. © 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: 21526 - Posted: 10.17.2015

A new clinical trial is set to begin in the United Kingdom using the powerful noses of dogs to detect prostate cancer in humans. While research has been done before, these are the first trials approved by Britain's National Health Service. The trials, at the Milton Keynes University Hospital in Buckinghamshire, will use animals from a nonprofit organization called Medical Detection Dogs, co-founded in 2008 by behavioral psychologist Claire Guest. "What we've now discovered is that lots of diseases and conditions — and cancer included — that they actually have different volatile organic compounds, these smelly compounds, that are associated with them," Guest tells NPR's Rachel Martin. "And dogs can smell them." The dogs offer an inexpensive, non-invasive method to accompany the existing blood tests for prostate cancer, which detect prostate-specific antigen, or PSA, Guest says. "It's a low false-negative but a very high false-positive, meaning that three out of four men that have a raised PSA haven't got cancer," she explains. "So the physician has a very difficult decision to make: Which of the four men does he biopsy? What we want to do is provide an additional test — not a test that stands alone but an additional test that runs alongside the current testing, which a physician can use as part of that patient's picture." The samples come to the dogs — the dogs never go to the patient. At the moment, our dogs would be screening about between a .5- to 1-ml drop of urine [or 1/5 to 1/10 teaspoon], so a very small amount. In the early days, of course, we know whether the samples have come from a patient with cancer or if the patient has another disease or condition, or is in fact healthy. © 2015 NPR

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: 21302 - Posted: 08.17.2015