Sarasota, FL - Smell and taste play essential roles in our daily lives. The chemical senses serve as important warning systems, alerting us to the presence of potentially harmful situations or substances, including gas leaks, smoke, and spoiled food. Flavors and fragrances are also important in determining what foods we eat and the commercial products we use. The pleasures derived from eating are mainly based on the chemical senses. Thousands of Americans experience loss of smell or taste each year resulting from head trauma, sinus disease, normal aging and neurological disorders, such as brain injury, stroke and Alzheimer's disease. By providing a better understanding of the function of chemosensory systems, scientific and biomedical research is leading to improvements in the diagnoses and treatment of smell and taste disorders. Some new findings to be presented at the meeting include: Newborn Sense of Smell May Save Life -- Odorization of the incubator prevents apneas in premature infants. Sperm Are Attracted by Chemicals -- Mechanisms of sperm navigation in turbulent flow. Human pheromone receptors -- De-orphaning, functional characterization and cAMP signalling of five human V1R-like receptors. Genetic Odorprints May Use Peptides -- Encoding immune system signals by the mammalian nose: The scent of genetic compatibility. Reduced Selection for Human Odor Receptor Genes -- A genomic perspective on the evolution of olfaction in primates.

Keyword: Chemical Senses (Smell & Taste)
Link ID: 7170 - Posted: 04.12.2005

New Haven, Conn.--Sensory deprivation causes changes in new cell size and excitability in the olfactory system, which governs the ability to smell, according to a study in Neuron by a Yale School of Medicine researcher. "This gives new insight into how stem cells in the olfactory system may be used to restore function in a brain that has been compromised by degenerative disease or trauma," said Gordon Shepherd, M.D., co-author of the paper and professor of neuroscience at Yale. Shepherd, on sabbatical with Pierre-Marie Lledo of the Pasteur Institute, investigated how the olfactory system responds to changes brought about by injury or different levels of activity. They closed one nostril in mice, a common sensory deprivation procedure, and then observed how the olfactory system adjusted to the change in sensory input. The olfactory system is one of the most plastic regions of the brain, with nerve cells that are continually replenished by stem cells. Stem cells in the nose replenish the sensory cells, which send the odor messages to the olfactory bulb. "There also are stem cells deep in the brain that replenish the interneurons, which carry out much of the processing of the odor messages that takes place in the olfactory bulb," Shepherd said.

Keyword: Chemical Senses (Smell & Taste)
Link ID: 7157 - Posted: 04.07.2005

Like many other marine creatures, Aplysia, a common sea slug, enlists chemical defenses against its predators, but the mechanisms by which such chemical attacks actually work against their intended targets are not well understood by researchers. New work has now shown that such chemical defenses can involve modes of trickery that had not previously been appreciated as components of chemical defense. When attacked by predatory spiny lobsters, sea slugs (also known as sea hares) release an inky secretion, termed ink and opaline, from a pair of glands. The new findings show that Aplysia's defensive secretion includes a variety of chemicals that together comprise a multi-pronged attack on the predator's nervous system, resulting in the usurpation of its normal behavioral control system and a confused response that facilitates the slug's ultimate escape. The team of researchers conducting the study, Cynthia Kicklighter, Zeni Shabani, and Paul Johnson, led by Charles Derby of Georgia State University, discovered that in addition to containing unpalatable, aversive chemicals, Aplysia's inky secretion contains large quantities of chemicals that are also found in the food of spiny lobsters and that indeed these chemicals serve to activate nervous-system pathways that control feeding behaviors of the lobster. The inky secretion also stimulates other behaviors in the lobster, including grooming and avoidance.

Keyword: Chemical Senses (Smell & Taste)
Link ID: 7091 - Posted: 03.29.2005

Scientists may have found what makes a tune catchy, after locating the brain area where a song's "hook" gets caught. A US team from Dartmouth College, reported in the journal Nature, played volunteers tunes with snippets cut out. They scanned for brain activity and found it centred in the auditory cortex - which handles information from ears. When familiar tunes played, the cortex activity continued during the blanks - and the volunteers indeed said they still mentally "heard" the tunes. Researchers have previously argued that catchy songs work by causing a "brain itch" that can only be scratched by repeating the tune. The Dartmouth team asked volunteers to listen to excerpts from familiar and unfamiliar songs with lyrics or instrumentals. These included the Rolling Stones' Satisfaction and the theme tune from The Pink Panther. Snippets of the music were removed at different points during the songs and replaced with silent gaps. The researchers used a brain scan called functional magnetic resonance imaging to see which parts of the brain were active while the volunteers listened to the tracks. After the experiment, the volunteers reported hearing a continuation of the song during the silent gaps when the tune was familiar, but not when the song was unfamiliar to them. When the researchers looked at the brain scans they found the individuals had more activity in specific regions of the brain during the silent gaps when the song was familiar, than when it was an unknown tune. (C)BBC

Keyword: Hearing
Link ID: 7018 - Posted: 03.12.2005

By Molly Bentley For nearly a decade, Cornell University researcher Christopher Clark has been eavesdropping on the ocean, hoping to decipher the enigmatic songs of whales. Using old US Navy hydrophones once employed to track submarines, he has collected thousands of acoustical tracks of singing blue, fin, humpback and minke whales. His bioacoustics lab is now able to pinpoint the location of individual singers, and determine the length of their song. As a result, he's had to redraw the map of whale acoustics. "The range is enormous," explained Dr Clark. "They have voices that span an entire ocean." Drawing on newly declassified acoustic data from the Sound Surveillance System (SOSUS), and using new tools that can crunch high volumes of them, Dr Clark has determined that whales' songs travel over thousands of kilometres and also that increasing noise pollution in the oceans impedes the animals' ability to communicate. It is not certain whether whales thousands of kilometres apart communicate directly with each other, or what their messages contain. But the results support a 30-year theory that, before the advent of modern shipping, the animals' booming voices would have resounded from one ocean basin to another. With sound that is loud and low, in other words, "beautifully designed" for long distance travel, the singing of a whale in the waters off Puerto Rico could carry 2,600km to the shores of Newfoundland, says Dr Clark. When scientists create a digital map of the sound as it propagates in the water, it "illuminates the entire ocean", he adds. The pan-oceanic range is fitting for massive 30-190-tonne creatures that rely on reflected sound, rather than light, to navigate. (C)BBC

Keyword: Hearing
Link ID: 6946 - Posted: 03.01.2005

Using a molecular approach to understanding human taste perception, researchers have made a new finding demonstrating that each individual's personal set of taste-receptor alleles, or gene variations, codes for distinct receptor proteins that determine individual differences in bitter-taste perception. These differences in perception are ubiquitous, underscoring the idea that, owing to slight variations in our genes for taste receptors, we all live in our own "taste worlds." Thus, we all perceive everyday foods such as teas, coffees, vegetables, meats, beer, cheeses, wines, and chocolates in our own way, potentially with no two tasters exactly alike. The reasons for these perceptual differences involve myriad genes and environmental influences, as well as the interplay between these two factors. The new finding regarding bitterness perception suggests that the taste-receptor genes and their multiple alleles play a dominant role in determining how we perceive the world of tastes. The longest-recognized and most famous genetically determined taste difference among people is the ability to taste PTC (phenylthiocarbamide) as bitter. PTC taste sensitivity varies tremendously among people; the threshold amount of PTC perceptible by individuals varies over a 1000-fold difference in concentration. These different sensitivities form a bimodal distribution in almost every population examined, and this distribution was interpreted as evidence that simple genetic differences, possibly involving only a single gene, underlie the PTC perceptual phenotype. The result was an 80-year-old search for the gene, which was identified last year.

Keyword: Chemical Senses (Smell & Taste); Genes & Behavior
Link ID: 6915 - Posted: 02.22.2005

Don't stop and smell the roses: "blinding" an insect's sense of smell may be the best repellent, according to research by Rockefeller University scientists "Pest insects have a profound negative impact on agriculture and human health," says Rockefeller University's Leslie Vosshall, Ph.D. "They are responsible for global losses of crops and stored agricultural products as well as the spread of many diseases." In the heated battle between people and insect pests, Vosshall and colleagues, in collaboration with the biotech company Sentigen Biosciences, Inc., report in the February 22nd issue of Current Biology that an understanding of insects' sense of smell may finally give humans the upper hand. The researchers studied four very different insect species: a benign insect favored by researchers, the fruit fly, which is attracted to rotting fruit, and three pest insects: the medfly, which is a citrus pest; the corn earworm moth, which damages corn, cotton and tomato crops; and the malaria mosquito, which targets humans. They found that one gene, shown to be responsible for the sense of smell in fruit flies, has the same function in these pest insects, which are separated by over 250 million years evolution "While all these insects have sensitive olfactory systems, they all have very different smell preferences," says Vosshall, head of the Laboratory of Neurogenetics and Behavior. "Yet this odorant receptor is highly conserved across all of these different species."

Keyword: Chemical Senses (Smell & Taste)
Link ID: 6912 - Posted: 02.22.2005

WASHINGTON, D.C. -- Why do whales in the North Atlantic Ocean seem to be moving together and coherently? What is impelling them forward. How do they communicate with each other, seemingly over thousands of miles of ocean? And how can this acoustical habitat be protected? For nearly nine years Cornell University researcher Christopher Clark -- together with former U.S. Navy acoustics experts Chuck Gagnon and Paula Loveday -- has been trying to answer these questions by listening to whale songs and calls in the North Atlantic using the navy's antisubmarine listening system. Instead of being used to track Soviet subs as they move through the Atlantic, the underwater microphones of the Sound Surveillance System (SOSUS) can track singing blue, fin, humpback and minke whales. From the acoustical maps he and his colleagues have obtained, Clark has come to realize that he has been thinking about whales at the wrong time scale. "There is a time delay in the water, and the response times for their communication are not the same as ours. Suddenly you realize that their behavior is defined not by my scale, or any other whale researcher's scale, but by a whale's sense of scale -- ocean-basin sized," he says.

Keyword: Hearing; Language
Link ID: 6906 - Posted: 02.21.2005

Synthetic sex pheromones are being developed as an ingenious way of luring randy cockroaches to their deaths. For years, scientists have been trying to identify the special chemical emitted by female German cockroaches that brings males running from afar. Now they have, Science magazine reports, and they hope to develop a special trap using the pheromone. The trap would contain a lethal pathogen, which sex-hungry males would pick up and pass through their colony. "We hope we will be able to attract them to traps which contain micro-organisms that will kill them eventually," said Wendell Roelofs, of Cornell University, New York, US. "And cockroaches are very gregarious so they will run back and interact with other members of the colony and they'll pass the pathogen on to them." The idea of using sex pheromones to catch pests is not a new one. It is all very well having an insect trap, but you need an effective bait. Sex pheromones, emitted by most female animals when they are ready to mate, are something that their male counterparts find irresistible. Scientists managed to identify and manufacture sex pheromones specific to certain species of cockroach some time ago. But the most menacing of them all - the German cockroach - remained a tough nut to crack. "The German cockroach is the biggest pest worldwide," said Dr Roelofs. "So people were looking way back in the 70s to see if they could synthesise it - but it eluded their attempts." The problem was nobody could find where the pheromones were being emitted from. (C)BBC

Keyword: Chemical Senses (Smell & Taste); Sexual Behavior
Link ID: 6904 - Posted: 02.19.2005

While the brain center called the nucleus accumbens (NAc) has been called a key component of the brain's "reward" pathways, researchers' experiments with rats have now shown that the center processes not only rewarding stimuli, but also aversive stimuli. The researchers found that not only does the NAc decide whether stimuli--in this case sweet sucrose or bitter quinine--are rewarding or aversive, but the center's neurons also encode learning associated with the stimuli. The NAc is located in the brain's limbic system, which generates feelings and emotions. It is the key brain center involved in reinforcing the taking of drugs of abuse. In their experiments, researchers led by Mitchell F. Roitman and Regina M. Carelli at Dr. Carelli's laboratory at University of North Carolina in Chapel Hill used recording microelectrodes to measure the electrophysiological response of neurons in the NAc of rats when they fed the rats small squirts of sucrose or quinine. The rats actively responded to the two tastes. For sucrose, they immediately licked and moved their mouths to ingest the sugar. In response to quinine, they gaped their mouths and rubbed their chins--the rat equivalent of "ptui."

Keyword: Chemical Senses (Smell & Taste); Drug Abuse
Link ID: 6883 - Posted: 02.17.2005

By ANAHAD O'CONNOR THE FACTS The amplified din of a rock concert or a few hours at a noisy bar can numb your hearing for an evening. But permanent damage? Studies show that most people regularly experience levels of noise and music that over time can leave them hard of hearing for life. Noise from recreational and work-related activities is responsible for hearing loss in about a third of hearing-impaired Americans. The damage is often accompanied by a nonstop buzzing called tinnitus. Dr. Eric Genden, an otolaryngologist at Mount Sinai, says it usually takes repeated doses of noise at levels from 90 decibels to 140 decibels to cause permanent harm. Those levels, he said, are fairly common. The clamor at most bars and clubs registers 110 to 120 decibels. Amplified music at a concert can reach 120 decibels and climb to an ear-rattling 130 decibels, rivaling the sound of a jet taking off. Sound from headphones can reach 100 decibels - louder than a lawn mower. Copyright 2005 The New York Times Company

Keyword: Hearing
Link ID: 6836 - Posted: 02.08.2005

EVANSTON, Ill. --- Scientists in the Auditory Neuroscience Laboratory at Northwestern University have developed a new diagnostic tool that can quickly and objectively identify disordered auditory processing of sound, a problem associated with learning impairments in many children. With early detection, these children have a high likelihood of benefiting from remediation strategies involving auditory training. The University recently licensed the technology, called BioMAP (Biological Marker of Auditory Processing), to Bio-logic Systems Corp., located in Mundelein, Ill. "The original versions of BioMAP have been used to demonstrate that brainstem-level neural timing deficits exist in roughly 30 percent of children with language-based learning problems such as dyslexia and in children whose speech perception is extraordinarily disrupted by environmental noise," said Nina Kraus, Hugh Knowles Professor and director of the Auditory Neuroscience Laboratory. "In our experience, children with these timing deficits appear to benefit most from remediation strategies involving computer-based auditory training. We anticipate that our partnership with Bio-logic will be fruitful in making this objective marker of auditory function available to clinics and private practices worldwide."

Keyword: Hearing
Link ID: 6829 - Posted: 02.08.2005

PHILADELPHIA, PA -- Variation in a taste receptor gene influences taste sensitivity of children and adults, accounting for individual differences in taste preferences and food selection, report a team of researchers from the Monell Chemical Senses Center. In addition to genes, age and culture also contribute to taste preferences, at times overriding the influence of genetics. The findings may help to explain why some children are more attracted to sweet-tasting foods, as well as why taste and food preferences appear to change with age. "The sense of taste is an important determinant of what children eat. We know that young children eat what they like. We also know that many children do not like bitter taste, thereby interfering with vegetable consumption and potentially limiting intake of important nutrients," comments lead author Julie Mennella, PhD, a developmental psychobiologist. "The recent Nobel Prize award demonstrates the importance of the identification of genes coding for taste and olfactory receptors. We took advantage of this new knowledge to look at how variation in taste genes might relate to the taste likes and dislikes of children and parents." In the study, to be published in the February 2005 issue of Pediatrics, researchers compared taste sensitivity and food-related behaviors across three genotypes of the TAS2R38 gene, which encodes a taste receptor responsive to bitter taste.

Keyword: Chemical Senses (Smell & Taste); Genes & Behavior
Link ID: 6823 - Posted: 02.07.2005

Stevie Wonder and Ray Charles are often cited as anecdotal evidence that blindness confers superior musical ability. In fact, systematic studies have shown that blind persons perform nonvisual tasks better than those with sight. Neuroimaging studies have suggested that areas of the brain normally devoted to vision become active when blind persons perform nonvisual tasks, but much remains to be learned about the nature and extent of this phenomenon. A new study published in the open-access journal PLoS Biology finds a strong correlation between superior sound localization skills and increased activity in the brain's visual center. The task of localizing sound--which requires integrating information available to one ear only (monaural sounds available, for example, when one ear is plugged) or information derived from comparing sounds binaurally--is particularly suited to investigating the neural remapping that seems to follow vision loss. In a previous study, Franco Lepore and colleagues showed that people who lost their sight at an early age could localize sound, particularly from monaural cues, better than those who could see. These findings suggested that areas of the brain normally dedicated to processing visual stimuli (the visual cortex, located at the back of the brain in the occipital lobe) might play a role in processing sound in these individuals. In the new study, the authors hypothesized that if visual cortex recruitment bolstered auditory function in some individuals, then visual cortex activity would correlate with individual differences in performance, and the degree of activity should predict such differences.

Keyword: Hearing; Vision
Link ID: 6745 - Posted: 01.25.2005

By JAMES GORMAN My infatuation with the amygdala has led me to wonder where aphasia and amusia overlap, a subject that neurologists have been investigating for many years. Damage to the brain can interfere with spoken language - aphasia. But it can also harm the ability to hear and produce melody. All this goes on in some part of the temporal lobe, not the amygdala, which is an almond-size structure in the brain (the word comes from the Greek for almond) that is involved with fear, emotion, sexuality and other aspects of humanity that lie below or behind the conscious mind. But this is off the point. I am infatuated with the word "amygdala," not the brain structure, although I suppose the meaning and the science contribute to the word's appeal. But I like its sound, you might say its musicality. And that has made me wonder about how speech and music overlap. For example, can a word be an earworm? An earworm is a tune that lodges itself in the brain and will not be moved. Songs like "It's a Small World" or "Ob-La-Di, Ob-La-Da" can become earworms. In a different class, "Là ci darem la mano," from Mozart's "Don Giovanni," might insinuate itself into every waking moment, although it seems wrong to compare such a lovely aria to an invertebrate. Copyright 2005 The New York Times Company

Keyword: Emotions; Hearing
Link ID: 6684 - Posted: 01.11.2005

Scientists say the way airflow around the nose is more complex than that in a jumbo jet's wing. Imperial College London researchers built a 3D model of the nose and used fluid to work out how air flows around it and how it senses different smells. They say the study, in Science, could help surgeons plan operations and the development of a cure for runny noses. The structure of the nose meant air eddied, whirled and re-circulated as it passed through the nose, the team said. Principal researcher Dr Denis Doorly said: "People are used to the flows around an aeroplane being complicated but that is in some ways simpler than understanding the flows inside the nose. "The geometry of the nose is highly complex, with no straight lines or simple curves like an aircraft wing and the regime of airflow is not simply laminar or turbulent." The team, funded by the Biotechnology and Biological Sciences Research Council, found the human sense of smell relies on a sample of air reaching the olfactory bulb at the top of the nose and that requires a sharp breathe and a high velocity shot of air to reach it. The geometry of the nose causes the air to move around in the vicinity of the bulb allowing smell to be sensed. The team mapped the air flow by using coloured beads which were put through the model noses and mapped by fast digital cameras. They also concluded the air flow was more complex than how bloods travels around the heart. (C)BBC

Keyword: Chemical Senses (Smell & Taste)
Link ID: 6672 - Posted: 01.07.2005

Traditionally viewed as supporting actors, cells known as glia may be essential for the normal development of nerve cells responsible for hearing and balance, according to new University of Utah research. The study is reported in the January 6, 2005 issue of Neuron and is co-authored by scientists at the University of Washington. "Using zebrafish as a model, we've demonstrated that glial cells play a previously unidentified role in regulating the development of sensory hair cell precursors -- the specialized neurons found in the inner ear of humans that make hearing possible. This research increases our understanding of how nerve cells develop and whether it may be possible to regenerate these types of cells in humans one day," said Tatjana Piotrowski, Ph.D., assistant professor of neurobiology and anatomy at the University of Utah School of Medicine. Scientists long have known that glial cells, or simply glia, are essential for healthy nerve cells. However, in the last 10 years scientists have learned that glia aren't just "glue" holding nerve cells together. Glia communicate with each other and even influence synapse formation between neurons. Piotrowski's research in zebrafish focuses on the development of sensory neurons known as hair cells. Like humans, zebrafish use hair cells to detect sound and motion. However, in humans hair cells are buried deep inside the inner ear making them difficult to access. Hair cells in zebrafish are located on the surface of their body and help the fish swim in groups and avoid predators.

Keyword: Glia; Hearing
Link ID: 6663 - Posted: 01.06.2005

By LEE BOWMAN, Scripps Howard News Service - You're at a crowded, noisy holiday party, trying to tune into the conversation of someone standing right next to you, but he or she might as well be speaking another language. Don't blame your hearing, or even the champagne. Researchers at the University of Florida in Gainesville have found that background noises don't just cover up conversation; they may actually scramble language-processing activity in the brain. Their experiments with rats are beginning to unravel why even perfectly loud speech may be hard to understand in a noisy room, a finding that has applications for everything from hearing aids to MP3 players. "Some people have a tremendously difficult time understanding speech in a noisy environment, and we've all had the experience of having someone tell us something, but we can't tell what it is that they are saying," said Purvis Bedenbaugh, an assistant professor of neuroscience at the university's medical college and the person who led the studies. "This research is the first step toward looking at why that would be." Their research was published earlier this year in The Proceedings of the National Academy of Sciences. The scientists examined how brain cells in alert rats responded to specific sounds while one of three standardized noises played in the background. Implanted electrodes recorded the activity in the auditory thalamus of the rats.

Keyword: Hearing
Link ID: 6637 - Posted: 12.31.2004

Sparrows can piece together a complete song by only hearing parts of it, scientists have found. The findings could help researchers establish how memory works in humans, especially in relation to how we learn languages. Professor Gary Rose, of the University of Utah, US, found that white crown sparrows learned a complete song, in the correct order, despite only ever hearing overlapping segments of it. It is hoped that working in this way with groups of young sparrows will shed light on the mechanisms of memory and learning. "The experiment was set up to determine whether or not birds could produce a normal song, having only heard components of the song - having never heard the whole song," Dr Rose told the BBC World Service. "That was to test something specific with respect to the representation of the memory of the song - is the memory a full account of a song in its normal cadence, or is the memory little bits of snippets?" he said on the Science In Action programme. Dr Rose taught the birds by playing back segments of the song twice a day. He took the original song - recorded from a sparrow in the field - and used a computer to fragment it. When played back, each bird was acoustically isolated from the others. "It wouldn't have been of much interest if they couldn't put it together - but they did," he said. "Our hypothesis was that if we provided information about the linkages between phrases... then the birds could potentially use that information to reconstruct the song." Each segment ended with an overlap to the beginning of the next. This overlap was the information the sparrows needed to piece the song together. (C)BBC

Keyword: Hearing; Language
Link ID: 6600 - Posted: 12.16.2004

Pharaoh ants use an appreciation of geometry to find their way home. Worker pharaoh ants travel to and from their colony along a series of branching paths scented with pheromones. But until now it was unclear how the ants knew which branch would lead them home. Duncan Jackson and his colleagues at the University of Sheffield, UK, noticed that various species of leafcutter and pharaoh ants - Monomorium pharaonis - lay trails radiating out from the nest that fork at an angle of 50° to 60°. When a returning ant reaches a fork in the trail, it usually takes the path which deviates least. In other words, it will change direction slightly to the right or left but will not make an acute turn back on itself. This means it always takes the path that leads back to the colony.

Keyword: Chemical Senses (Smell & Taste)
Link ID: 6593 - Posted: 12.16.2004