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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
Jörn Lötsch, Dario Kringel, Thomas Hummel
The complexity of the human sense of smell is increasingly reflected in complex and high-dimensional data, which opens opportunities for data driven approaches that complement hypothesis driven research. Contemporary developments in computational and data science, with its currently most popular implementation as machine learning, facilitate complex data driven research approaches. The use of machine-learning in human olfactory research included major approaches comprising (i) the study of the physiology of pattern-based odor detection and recognition processes, (ii) pattern recognition in olfactory phenotypes, (iii) the development of complex disease biomarkers including olfactory features, (iv) odor prediction from physicochemical properties of volatile molecules and (v) knowledge discovery in publicly available big databases...
October 27, 2018: Chemical Senses
Jiang Xu, Brian Lewandowski, Toshio Miyazawa, Yasutaka Shoji, Karen Yee, Bruce Bryant
Overconsumption of NaCl has been linked to increased hypertension related morbidity. Compounds that can enhance NaCl responses in taste cells could help reduce human NaCl consumption without sacrificing perceived saltiness. Spilanthol is an unsaturated alkylamide isolated from the Jambu plant (Acmella oleracea) that can induce tingling, pungency, and numbing in the mouth. Structurally similar fatty acid amides, such as sanshool, elicit numbing and tingling sensations by inhibiting 2-pore domain potassium leak channels on trigeminal sensory neurons...
October 26, 2018: Chemical Senses
Jennifer E Douglas, Cailu Lin, Corrine J Mansfield, Charles J Arayata, Beverly J Cowart, Andrew I Spielman, Nithin D Adappa, James N Palmer, Noam A Cohen, Danielle R Reed
TAS2R38 is a human bitter receptor gene with a common but inactive allele; people homozygous for the inactive form cannot perceive low concentrations of certain bitter compounds. The frequency of the inactive and active form of this receptor is nearly equal in many human populations, and heterozygotes with one copy of the active form and one copy of the inactive form have the most common diplotype. However, even though they have the same genotype, heterozygotes differ markedly in their perception of bitterness, perhaps in part because of differences in TAS2R38 mRNA expression...
October 23, 2018: Chemical Senses
Andreas Keller
No abstract text is available yet for this article.
October 9, 2018: Chemical Senses
Bernd Lindemann
No abstract text is available yet for this article.
October 9, 2018: Chemical Senses
Vladimir Shiriagin, Sigrun I Korsching
A sensory deficit both at the individual and the species level can be compensated by increased acuity in other senses. The loss of vision in blind cavefish, Astyanaxmexicanus appears to be partially counterbalanced by enhanced chemosensory perception. Whether such improvement also involves adaptive changes in chemosensory receptor repertoires was unknown. The typical bitter taste receptor repertoire of teleost fishes is reported as three to five genes, much smaller than that of many terrestrial species. Interestingly, several fish species, e...
October 5, 2018: Chemical Senses
L Koehler, A Fournel, K Albertowski, V Roessner, J Gerber, C Hummel, T Hummel, M Bensafi
Autism Spectrum Disorders (ASDs) are characterized by atypical sensory functioning in the visual, tactile, and auditory systems. Although less explored, olfactory changes have been reported in ASD patients. To explore these changes on a neural level, 18 adults with ASD and 18 healthy neurotypical controls were examined in a 2-phase study. Participants were first tested for odor threshold and odor identification. Then, (i) structural magnetic resonance (MR) images of the olfactory bulb were acquired, and (ii) a functional MR imaging olfaction study was conducted...
September 14, 2018: Chemical Senses
Julie L Colvin, Alexa J Pullicin, Juyun Lim
Previous studies have shown that there are differences in taste responses between various regions of the tongue. Most of those studies used a controlled 'passive' tasting mode due to the nature of investigation. However, food is rarely tasted in a passive manner. In addition, recent studies have suggested that humans can taste maltooligosaccharides (MOS) and that the gustatory detection of MOS is independent of the known sweet receptor. It is unknown whether regional differences in responsiveness to MOS exist...
August 27, 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
Caterina Dinnella, Erminio Monteleone, Maria Piochi, Sara Spinelli, John Prescott, Lapo Pierguidi, Flavia Gasperi, Monica Laureati, Ella Pagliarini, Stefano Predieri, Luisa Torri, Sara Barbieri, Enrico Valli, Piergiorgio Bianchi, Ada Braghieri, Alessandra Del Caro, Rossella Di Monaco, Saida Favotto, Elisabetta Moneta
Despite considerable research investigating the role of 6-n-propylthiouracil bitterness perception and variation of fungiform papillae density in food perception, this relationship remains controversial as well as the association between the 2 phenotypes. Data from 1119 subjects (38.6% male; 18-60 years) enrolled in the Italian Taste project were analyzed. Responsiveness to the bitterness of 6-n-propylthiouracil was assessed on the general Labeled Magnitude Scale. Fungiform papillae density was determined from manual counting on digital images of the tongue...
November 1, 2018: Chemical Senses
Joyce Tang, Steven L Youngentob, John I Glendinning
The aversive flavor of ethanol limits intake by many consumers. We asked whether intermittent consumption of ethanol increases its oral acceptability, using rats as a model system. We focused on adolescent rats because they (like their human counterparts) have a higher risk for alcohol overconsumption than do adult rats following experience with the drug. We measured the impact of ethanol exposure on 1) the oral acceptability of ethanol and surrogates for its bitter (quinine) and sweet (sucrose) flavor components in brief-access lick tests and 2) responses of the glossopharyngeal (GL) taste nerve to oral stimulation with the same chemical stimuli...
September 22, 2018: Chemical Senses
Allison N Baker, Anjelica M Miranda, Nicole L Garneau, John E Hayes
TAS2R38 gene variants, which confer sensitivity to specific bitter tastants (e.g., 6-n-propylthiouracil), have been repeatedly associated with lower alcohol use via greater bitterness perception, but research exploring TAS2R38 variation in relation to smoking shows mixed results. In both, the working hypothesis is that 1 or more copies of the functional allele increases bitterness and may provide a barrier to early use. Such a barrier to initiation may, conceivably, manifest as differential rates of current use across diplotypes...
September 22, 2018: Chemical Senses
Torben Noto, Guangyu Zhou, Stephan Schuele, Jessica Templer, Christina Zelano
Nasal inhalation is the basis of olfactory perception and drives neural activity in olfactory and limbic brain regions. Therefore, our ability to investigate the neural underpinnings of olfaction and respiration can only be as good as our ability to characterize features of respiratory behavior. However, recordings of natural breathing are inherently nonstationary, nonsinusoidal, and idiosyncratic making feature extraction difficult to automate. The absence of a freely available computational tool for characterizing respiratory behavior is a hindrance to many facets of olfactory and respiratory neuroscience...
September 22, 2018: Chemical Senses
Charles Spence, Qian Janice Wang
Complexity is a term that is often invoked by those writing appreciatively about the taste, aroma/bouquet, and/or flavor of food and drink. Typically, the term is used as though everyone knows what is being talked about. Rarely is any explanation given, and the discussion soon moves on to other topics. However, oftentimes it is not at all clear what, exactly, is being referred to. A number of possibilities are outlined here, including physical complexity at the level of individual molecules, at the level of combinations of molecules giving rise to a specific flavor profile (e...
August 24, 2018: Chemical Senses
Mackenzie Hannum, Margaret A Stegman, Jenna A Fryer, Christopher T Simons
The Duality of Smell hypothesis suggests odorants delivered orthonasally elicit different sensations compared with those delivered retronasally despite activating the same receptors in the olfactory epithelium. Presently, we investigated this further using a matching paradigm free from odorant or semantic memory bias. Subjects were asked to evaluate an aroma delivered in one condition (orthonasal or retronasal delivery) and match the same aroma from 4 unknowns evaluated in the same or different delivery conditions...
August 24, 2018: Chemical Senses
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