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Chemical Senses

Galih Kusuma Aji, Frederick J Warren, Eugeni Roura
Starch-related sweet taste perception plays an important role as a part of the dietary nutrient sensing mechanisms in the oral cavity. However, the release of sugars from starchy foods eliciting sweetness has been less studied in humans than in laboratory rodents. Thus, twenty-eight respondents were recruited and evaluated for their starch-related sweet taste perception, salivary alpha-amylase (sAA) activity, oral release of reducing sugars, and salivary leptin. The results demonstrated that a two-minute oral mastication of starchy chewing gum produced an oral concentration of maltose above the sweet taste threshold and revealed that the total amount of maltose equivalent reducing sugars produced was positively correlated with the sAA activity...
February 7, 2019: Chemical Senses
Stuart McLean, Noel W Davies, David S Nichols
Like all animals, the red fox uses chemical signals for social communication. The supracaudal or tail gland smells of violets, attributed to the presence of carotenoid degradation products, or apocarotenoids, which commonly occur as aromatics in flowers. We have more fully characterised the scent chemistry of the fox tail gland. Volatile chemicals were analysed by GC-MS and identified from their electron ionisation mass spectra and Kovats retention indices. The three previously reported apocarotenoids were confirmed, and many additional compounds found...
February 7, 2019: Chemical Senses
Paulina Morquecho-Campos, Maria Larsson, Sanne Boesveldt, Jonas K Olofsson
Human olfactory function requires the identification of everyday odors. A characteristic feature of olfaction is that most people find it hard to identify and name common odors, and when odors are presented simultaneously in mixtures, performance is even further compromised. Few studies have systematically assessed how training might enhance identification of single odors and mixtures. This study compared how odor identification training with either single odors or binary mixtures affected identification performance, as well as transfer effects to untrained tasks and odors...
February 3, 2019: Chemical Senses
Guo Feng, Yuan Zhuang, Fangshu Yao, Yuting Ye, Qiannong Wan, Wen Zhou
Smell identification ability reflects the functional integrity of the human olfactory system. Its deficit is a prodromal marker for Parkinson's disease and is also implicated in Alzheimer's disease and other neurological and psychiatric disorders. Considering the impact of cultural factors on odor identifiability, we have developed a smell identification test specifically for the Chinese population (CSIT), which includes 40 odor items that are familiar to this population, presented in a multiple-choice format...
January 30, 2019: Chemical Senses
Shawn D Burton, Mia Wipfel, Michael Guo, Thomas P Eiting, Matt Wachowiak
Understanding how sensory space maps to neural activity in the olfactory system requires efficiently and flexibly delivering numerous odorants within single experimental preparations. Such delivery is difficult with current olfactometer designs, which typically include limited numbers of stimulus channels and are subject to inter-trial and inter-channel contamination of odorants. Here, we present a novel olfactometer design that is easily constructed, modular, and capable of delivering an unlimited number of odorants in air with temporal precision and no detectable inter-trial or inter-channel contamination...
January 18, 2019: Chemical Senses
Ciara Fitzgerald, Gretchen Wiese, Ranjani N Moorthi, Sharon M Moe, Kathleen Hill Gallant, Cordelia A Running
Dysgeusia (abnormal taste) is common in those with chronic kidney disease and contributes to poor nutritional intake. Previous sensory work has shown that taste improves after dialysis sessions. The goal of this pilot study was to characterize altered taste perceptions in patients on dialysis compared to healthy adults, and to evaluate relationships between serum parameters with taste perceptions. We hypothesized that patients undergoing dialysis would experience blunted taste intensities compared to controls, and that serum levels of potential tastants would be inversely related to taste perception of compounds...
January 9, 2019: Chemical Senses
Elie Chamoun, Angel A S Liu, Lisa M Duizer, Gerarda Darlington, Alison M Duncan, Jess Haines, David W L Ma
Taste is fundamentally important for food selection. While measures of taste sensitivity and preference have been refined over several decades, it remains largely unknown how these measures relate to each other and to food preferences. The objectives of this study were to examine, in healthy adults (age 24.6 ± 0.6 years, n=49), 1) correlations among measures of taste sensitivity, including detection threshold (DT) and suprathreshold sensitivity (ST), and taste preference (PR) within sweet, salt, sour, umami, and fat tastes, 2) the underlying associations among DT, ST and PR measurements using principal component analysis, and 3) associations between measured PR and bitter intensity rating with self-reported food PRs...
December 26, 2018: Chemical Senses
Gloria Fleming, Beverly A Wright, Donald A Wilson
Perceptual learning is an enhancement in discriminability of similar stimuli following experience with those stimuli. Here, we examined the efficacy of adding additional active training following a standard training session, compared to additional stimulus exposure in the absence of associated task performance. Mice were trained daily in an odor-discrimination task, and then, several hours later each day, received one of three different manipulations: 1) a second active-training session, 2) non-task-related odor exposure in the home cage, or 3) no second session...
December 24, 2018: Chemical Senses
Tatiana Forestier, Christophe Féron, Chloé Leroy, Patrizia d'Ettorre, Patrick Gouat
Mice can obtain information about a new food source through olfactory cues of conspecifics and consequently develop an attraction for this diet. The social transmission of food preference (STFP) takes place directly, during an encounter with a conspecific or indirectly, via feces. In indirect STFP, the digestive process can degrade odorant compounds characterizing the food, impairing the matching between feces and food. In a previous study, indirect STFP was efficient when the information support was a composite odorant...
December 20, 2018: Chemical Senses
Alexa J Pullicin, Michael H Penner, Juyun Lim
Although sweet-tasting saccharides possess similar molecular structures, their relative sweetness often varies to a considerable degree. Current understanding of saccharide structure/sweetness interrelationships is limited. Understanding how certain structural features of saccharides and/or saccharide analogs correlate to their relative sweetness can provide insight on the mechanisms underlying sweetness potency. Maltotriose is a short-chain glucose-based oligosaccharide, which we recently reported to elicit sweet taste...
December 19, 2018: Chemical Senses
Ingrid Ekström, Maria Josefsson, Maria Larsson, Michael Rönnlund, Steven Nordin, Jonas K Olofsson
Olfactory impairments may provide early indications of future health outcomes in older adults. Thus, an important question concerns whether these impairments can be self-assessed. Previous findings of cross-sectional studies indicate low correlations between self-reported olfactory function and objective olfactory performance. On the other hand, subjective olfactory impairments predict future dementia and mortality in longitudinal settings. No previous study has assessed the relationship between subjectively and objectively measured decline in olfaction over time...
December 13, 2018: Chemical Senses
Alan C Spector, Natasha Kapoor, Ruth K Price, M Yanina Pepino, M Barbara E Livingstone, Carel W le Roux
This article provides a summary of the topics discussed at the symposium titled Bariatric Surgery and Its Effects on Taste and Food Selection which was held at the Fortieth Annual Meeting of the Association for Chemoreception Sciences. Bariatric surgery such as Roux-en-Y gastric bypass (RYGB) is currently one of the most effective treatments available for weight loss and Type-2 diabetes. For this reason, it is of great interest to clinicians as well as to basic scientists studying the controls of feeding and energy balance...
December 4, 2018: Chemical Senses
Ernesto Tarragon, Juan José Moreno
The herb Cannabis sativa has been traditionally used in many cultures and all over the world for thousands of years as medicine and recreation. However, because it was brought to the Western world in the late 19th century, its use has been a source of controversy with respect to its physiological effects as well as the generation of specific behaviors. In this regard, the CB1 receptor represents the most relevant target molecule of cannabinoid components on nervous system and whole-body energy homeostasis. Thus, the promotion of CB1 signaling can increase appetite and stimulate feeding, whereas blockade of CB1 suppresses hunger and induces hypophagia...
November 27, 2018: Chemical Senses
Diogo Manoel, Melanie Makhlouf, Antonio Scialdone, Luis R Saraiva
Aiming to unravel interspecific differences in olfactory preferences, we performed comparative studies of odor valence in flies, mice, and humans. Our analysis suggests a model where flies and mice share similar olfactory preferences, but neither species share odor preferences with humans. This model contrasts with a previous study by Mandairon and colleagues, which suggested that the olfactory preferences of mice and humans are similar. A probabilistic examination revealed that underpowered studies can result in spurious significant correlations, which can account for the differences between both studies...
November 15, 2018: Chemical Senses
Paul A M Smeets, Cees de Graaf
Beer is a popular alcoholic beverage world-wide. Non-alcoholic beer is increasingly marketed. Brain responses to beer and non-alcoholic beer (NA-beer) have not been compared. It could be that the flavor of beer constitutes a conditioned stimulus associated with alcohol reward. Therefore, we investigated whether oral exposure to NA-beer with or without alcohol elicits similar brain responses in reward-related areas in a context where regular alcoholic beer is expected. Healthy men (n=21) who were regular beer drinkers were scanned using functional MRI...
November 13, 2018: Chemical Senses
Danielle Nachtigal, Kendra Andrew, Barry G Green
This study investigated the effect of temperature on taste and chemesthetic sensations produced by the prototypical salty and sour stimuli NaCl and citric acid. Experiment 1 measured the perceived intensity of irritation (burning, stinging) and taste (saltiness, sourness) produced on the tongue tip by brief (3 sec) exposures to suprathreshold concentrations of NaCl and citric acid at 3 different temperatures (12, 34, 42°C). No significant effects of temperature were found on the taste or sensory irritation of either stimulus...
November 12, 2018: Chemical Senses
Kelly E Fredericksen, Kelsey A McQueen, Chad L Samuelsen
The mediodorsal thalamus is a higher-order thalamic nucleus critical for many cognitive behaviors. Defined by its reciprocal connections with the prefrontal cortex, the mediodorsal thalamus receives strong projections from chemosensory cortical areas for taste and smell, gustatory cortex and piriform cortex. Recent studies indicate the mediodorsal thalamus is involved in experience-dependent chemosensory processes, including olfactory attention and discrimination and the hedonic perception of odor-taste mixtures...
November 2, 2018: Chemical Senses
Amy R Gordon, Bruce A Kimball, Kimmo Sorjonen, Bianka Karshikoff, John Axelsson, Mats Lekander, Johan N Lundström, Mats J Olsson
Contagious disease is a major threat to survival, and the cost of relying on the immune system to defeat pathogens is high; therefore, behavioral avoidance of contagious individuals is arguably an adaptive strategy. Animal findings demonstrate the ability to detect and avoid sick individuals by the aid of olfactory cues, and a recent study indicated that human axillary odor also becomes more aversive as a function of immune activation. By injecting healthy human participants with lipopolysaccharide (0.6 ng/kg body weight) to experimentally induce inflammation, this study demonstrates that natural daily rhythms of urine odor-its perceived dimensions and volatile profile-are altered within hours of inflammation onset...
November 1, 2018: Chemical Senses
Daphnée Poupon, Pauline Fernandez, Salomé Archambault Boisvert, Chloé Migneault-Bouchard, Johannes Frasnelli
Identifying odors within mixtures is a difficult task: humans are able to recognize only up to 4 odors within a mixture. We wanted to test the effects of olfactory training on this ability. We used 7 odorants to create 35 olfactory stimuli of 1, 2, 3, 4, or 5 odorants. The task consisted of identifying the odorants present within the mixture. We trained novices on this task for 5 days: they came to the laboratory to perform the task once a day before coming back for the final testing. Then, we compared them to sommeliers, thus olfaction experts, and untrained novices...
November 1, 2018: Chemical Senses
Julia Mohrhardt, Maximilian Nagel, David Fleck, Yoram Ben-Shaul, Marc Spehr
In many mammalian species, the accessory olfactory system plays a central role in guiding behavioral and physiological responses to social and reproductive interactions. Because of its relatively compact structure and its direct access to amygdalar and hypothalamic nuclei, the accessory olfactory pathway provides an ideal system to study sensory control of complex mammalian behavior. During the last several years, many studies employing molecular, behavioral, and physiological approaches have significantly expanded and enhanced our understanding of this system...
November 1, 2018: Chemical Senses
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