Chemosensory Perception最新文献

Most functional magnetic resonance imaging (fMRI) studies of taste deliver small quantities of liquids over roughly 45?min to repeatedly sample brain response to tastants. Within this time participants frequently report that their need to urinate increases.

Since both gustatory and interoceptive information are represented in the anterior insular cortex, we evaluated whether perceived need to urinate influenced insular responses to the receipt of a small bolus of milkshake in two datasets (n?=?45).

Change in pre- to post-scan ratings of desire to urinate was inversely related to anterior insular response to milkshake.

This finding demonstrates that micturition drive influences insular response to milkshake and supports previous reports of overlapping gustatory and visceral representation within human anterior insular cortex.

Changes in sweet and bitter taste perception during pregnancy have been reported in a limited number of studies leading, however, to inconclusive results. The current study aimed to investigate possible differences in perceived intensity and liking of sweetness and bitterness between pregnant and nonpregnant women.

Forty-six pregnant and 45 nonpregnant women evaluated taste intensity and liking of five samples of each of four different products: two sweet (cake and apple + berry juice) and two bitter (salad and grapefruit juice). Product samples varied in sweetness and bitterness, respectively. Pregnant women completed also a self-administered questionnaire on changes in sweet and bitter taste perception due to pregnancy.

Perceived intensity of sweetness and bitterness was not different between pregnant and nonpregnant women for any of the products. However, the liking of the least sweet apple + berry juice was significantly higher, and the optimal preferred sugar content was significantly lower in pregnant compared to nonpregnant women. With regards to self-report, pregnant women who reported higher sensitivity in sweet or bitter taste did not have significantly different intensity scores from those with no self-reported changes. The apple + berry juice sample highest in sugar content was liked less by pregnant women who reported higher sensitivity toward sweet taste compared to those who reported no change.

This study provides evidence that pregnant women may prefer lower sugar content in a juice mixture compared to nonpregnant women. Future research should focus on the possible occurrence of this phenomenon in other beverages and foods, as well.

A cross-sensory interaction between gustatory and trigeminal nerves occurs in the anterior tongue. Surgical manipulations have demonstrated that the strength of this relationship varies across development. Capsaicin is a neurotoxin that affects fibers of the somatosensory lingual nerve surrounding taste buds, but not fibers of the gustatory chorda tympani nerve which synapse with taste receptor cells. Since capsaicin is commonly consumed by many species, including humans, the experimental use of this neurotoxin provides a naturalistic perturbation of the lingual trigeminal system. Neonatal or adult rats consumed oral capsaicin for 40?days, and we examined the cross-sensory effect on the morphology of taste buds across development.

Rats received moderate doses of oral capsaicin, with chronic treatments occurring either before or after taste system maturation. Tongue morphology was examined either 2 or 50?days after treatment cessation. Edema, which has been previously suggested as a cause of changes in capsaicin-related gustatory function, was also assessed.

Reductions in taste bud volume occurred 50?days, but not 2?days post-treatment for rats treated as neonates. Adult rats at either time post-treatment were unaffected. Edema was not found to occur with the 5?ppm concentration of capsaicin we used.

Results further elucidate the cooperative relationship between these discrete sensory systems and highlight the developmentally mediated aspect of this interaction.

Chronic exposure to even moderate levels of noxious stimuli during development has the ability to impact the orosensory environment, and these changes may not be evident until long after exposure has ceased.

In many developed nations, natural gas (so-called city gas) is supplied as a utility for cooking, heating, and hot-water supply. Because natural gas is odorless, city gas must be odorized so that it can be detected in the event of a leak. Although high adaptation tolerance is an important criterion for city gas odorants, there is yet no standard method of evaluating the psychophysical suitability of new candidate odorants in terms of olfactory adaptation. In order to address this situation, we developed a method for psychophysical screening of new candidate odorants for use in city gas based on adaptation tolerance.

We used the main component of the conventional city gas odor (tertbutylmercaptan, TBM) and six new candidate odorants: cyclohexene (CH), ethyl isobutyrate (EI), isovaleric acid (IVA), 2-hexene (HEX), 1,5-cyclooctadiene (COD), and 1-methylpyrrolidine (MEP). Participants evaluated the perceived intensity of a continuously presented odor at a fixed concentration. After the time-intensity curves were quantitatively classified into fast or slow adaptation patterns, we compared the number of intensity curves classified into each pattern between TBM and each new odorant.

Our results revealed that HEX has a significantly higher adaptation tolerance than TBM, and that the other five new candidate odorants were almost equivalent to TBM in terms of adaptation tolerance.

We concluded that all of the new candidate odorants used in this study passed the psychophysical screen based on adaptation tolerance, and are therefore suitable for use in city gas.

Fat can be perceived through mouthfeel, odour and taste, but the influence of these modalities on fat perception remains undefined. Fatty acids are stimuli and individual sensitivity to fatty acids varies. Studies show association between fatty acid sensitivity, dietary intake and BMI, but results are conflicting. Therefore, this study examined this association, and the effect of modalities on fat perception.

Two sub-studies were conducted. In study 1 (n = 46), fat intensity was assessed by milk/cream mixtures varying by five fat levels. Fat intensity was rated under four conditions: mouthfeel odour-masked, mouthfeel-masked, odour masked and with no masking. Mouthfeel masking was achieved using thickener and paraffin, odour masking using nose-clips. Fatty acid sensitivity was measured by 3-AFC staircase method using milk containing oleic acid (0.31–31.4 mM). In study 2 (n = 51), more fat levels were added into the intensity rating. A 2-AFC discrimination test was used to confirm whether fat levels could be distinguished. In the sensitivity test, a wider range of oleic acid was included.

Fat intensity was rated higher without nose clips (p < 0.0001), implying that odour increased fat perception. Mouthfeel-masked samples were rated higher, showing that increased viscosity and lubricity enhanced fat perception (p < 0.0001). Participants could distinguish fat levels based on “taste” in rating tests and 2-AFC tests. Participants were divided into high-/medium-/low-sensitivity groups. No significant difference was found in fat intensity between groups; however, the high-sensitivity group discriminated more fat levels. No association between sensitivity groups, nutrient intake or BMI was found.

Mouthfeel and odour can enhance fat perception. Fat level can be discriminated based on taste.

Evidence for olfactory lateralization is mixed, although a left-sided benefit for odor identification seems likely. Whether lateralization of function is moderated by variables such as gender and handedness has been previously explored. However, there has been no test of whether psychopathy and empathy—personality characteristics which may themselves affect lateralization and which can affect olfactory function—moderate olfactory lateralization.

Eighty men and women engaged in mono-rhinal testing for odor threshold, identification, and discrimination ability, as well as completing standardized measures of psychopathy and empathy.

While there was a clear left-sided benefit for odor identification and discrimination, we found no evidence that psychopathy or empathy moderated these effects. When the current data were combined with that from previous studies, we found that psychopathy was correlated with poorer odor discrimination and identification, whereas empathy was correlated with enhanced discrimination and identification, pointing to processing commonalities between olfaction, psychopathy, and empathy.

In the present study, we explore the existence of cross-cultural differences in odour-colour correspondences between two European countries with geographic proximity and shared history: England and France. Moreover, we test whether a single chromatic arrangement can be used to represent an odour in both countries, even if the odour-colour association for this odour differed.

The responses of 59 British and 60 French participants to the same set of odorants were compared. In the second part of the study, the ability of ‘chromatic cards’ to represent odours was tested. Those chromatic cards are objective coloured arrangements generated by a new patented scientific tool developed at Lorraine University (patent FR no. 1255688). This tool is based on a neural network algorithm for colour forecasting. It generates a chromatic card that represents any odour from its chemical composition and sensory description. In this study, participants were presented with three cards obtained from an analysis of lavender, cucumber and peppermint odours. First, the participants had to name the odour evoked by each card. Next, they selected from amongst three different olfactory stimuli the one that best matched each card.

Significant colour characterisations were observed for each and every one of the odours tested in both populations. Moreover, both commonalities and differences were reported between the two populations in terms of the odour-colour associations that they exhibited. The chromatic representations evoked the appropriate odour percept and were significantly associated to their related odours in both of the populations.

These findings highlight the existence of common colour representations of odours amongst French and British participants, though some differences were also found. Despite these differences, we were able to validate the relevancy of using single chromatic arrangements in both countries in order to communicate odour information. The latter result may open up the way for a number of potentially important applications in the design and marketing of both food and non-food products.

Food choice and habitual diet-related health outcomes are strongly influenced by the oral sensations elicited by food. Of the biological-based mediators of orosensation, thermal tasting—the capacity to experience phantom taste sensations on lingual thermal stimulation—has not been investigated with respect to orosensation and liking of sampled foods.

Twenty-three female thermal tasters (TTs) and 21 female thermal non-tasters (TnTs) scored liking of (9-point hedonic scale) and the intensity of orosensations elicited by (gVAS) 22 food and beverage items in duplicate using a randomized complete block design in a customized sensory evaluation laboratory. Foods selected included high fat, high sugar, and high salt items. Sampled items were grouped according to the dominant orosensation(s) elicited (sweet, bitter, sour, salty, astringent, creamy, crunchy, crispy, firm, menthol cool, and grainy), and intensity and liking assessed for each group.

No significant differences were found for thermal tasting status (TTS) in intensity ratings of orosensory groupings (p(t)?>?0.05). TnTs gave higher liking ratings for creamy foods than TTs (t?=?5.99, p?=?0.015), and their liking of the “aversive” food grouping was higher than for TTs and approached significance (t?=?2.97, p?=?0.086).

The previously reported variation in orosensation due to TTS observed with simple aqueous solutions, and some beverages may not extend to sampled foods. However, differences in liking are suggested for some food groupings and are worthy of further investigation.

Individual differences in taste sensitivity have been considered the primary chemosensory factor in studies of chemical senses/ingestive behavior. Recent findings suggest, however, that retronasal odor perception is equally important in food preference and selection and, furthermore, the presence of a congruent taste can modulate responsiveness to retronasally perceived odors. The primary objective of this study was to measure individual differences in responsiveness to food odors in the presence and absence of a congruent taste. In order to achieve this goal, we experimentally manipulated the way taste and odor stimuli are presented. We hypothesized that when measured independently, variations across subjects in responsiveness to retronasal odors are greater than those of tastes, but that these variations are effectively reduced by the presence of a congruent taste, especially for the older cohort.

Two groups of subjects (young vs. old cohorts) were asked to sample two tastants, four food odorants, and the congruent taste-odor pairs, and rate intensities for appropriate categories.

Results showed that responsiveness to odors varied greatly across individuals compared to that of tastes and further that variations in odor responsiveness were greater for old compared to young cohort. In the presence of a congruent taste, however, the variations in responsiveness to the odors were significantly reduced, in particular for the old cohort.

The current data suggest that older individuals and those with low olfactory sensitivity may not recognize the reduced sensitivity when consuming foods.

A great degree of interindividual variability has been reported in measures of psychophysical olfactory performance and odor awareness in both children and adults. Previous studies have suggested the possibility that one of the factors that might contribute to this variability could be the degree of odor exposure experienced in everyday contexts.

In the present study, we hypothesized that children exposed to a greater variety of odors on a more frequent basis exhibit higher odor identification, discrimination, and odor awareness scores.

We have found an effect of odor exposure on one aspect of the children’s olfactory knowledge as reflected in their reports of olfactory behavior, but not olfactory abilities. In so doing, we have replicated some of the previous findings in the literature of the female advantage in the olfactory domain. Namely, we report that girls showed a more profound metacognitive understanding of their sense of smell and a greater degree of olfaction-oriented behavior, which was not accounted for by a gender difference in verbal fluency. Nevertheless, girls did not outperform boys on any of the olfactory tests.

Semi-longitudinal and longitudinal studies in verbally proficient children, employing both self- and parental reports of children’s odor exposure and repeated olfactory testing, may provide insight into whether children exposed more frequently to a greater variety of odors over the longer term come to exhibit greater odor awareness and superior performance in olfactory tests.