Molecular complexity determines the number of olfactory notes and the pleasantness of smells

One major unresolved problem in olfaction research is to relate the percept to the molecular structure of stimuli. The present study examined this issue and showed for the first time a quantitative structure-odor relationship in which the more structurally complex a monomolecular odorant, the more numerous the olfactory notes it evokes. Low-complexity odorants were also rated as more aversive, reflecting the fact that low molecular complexity may serve as a warning cue for the olfactory system. Taken together, these findings suggest that molecular complexity provides a framework to explain the subjective experience of smells

Semantic Knowledge Influences Prewired Hedonic Responses to Odors

Background Odor hedonic perception relies on decoding the physicochemical properties of odorant molecules and can be influenced in humans by semantic knowledge. The effect of semantic knowledge on such prewired hedonic processing over the life span has remained unclear. Methodology/Principal Findings The present study measured hedonic response to odors in different age groups (children, teenagers, young adults, and seniors) and found that children and seniors, two age groups characterized by either low level of (children) or weak access to (seniors) odor semantic knowledge, processed odor hedonics more on the basis of their physicochemical properties. In contrast, in teenagers and young adults, who show better levels of semantic odor representation, the role of physicochemical properties was less marked. Conclusions/Significance These findings demonstrate for the first time that the biological determinants that make an odor pleasant or unpleasant are more powerful at either end of the life span

More Than Smell - COVID-19 Is Associated With Severe Impairment of Smell,Taste, and Chemesthesis

Recent anecdotal and scientific reports have provided evidence of a link between COVID-19 and chemosensory impairments, such as anosmia. However, these reports have downplayed or failed to distinguish potential effects on taste, ignored chemesthesis, and generally lacked quantitative measurements. Here, we report the development, implementation, and initial results of a multilingual, international questionnaire to assess self-reported quantity and quality of perception in 3 distinct chemosensory modalities (smell, taste, and chemesthesis) before and during COVID-19. In the first 11 days after questionnaire launch, 4039 participants (2913 women, 1118 men, and 8 others, aged 19-79) reported a COVID-19 diagnosis either via laboratory tests or clinical assessment. Importantly, smell, taste, and chemesthetic function were each significantly reduced compared to their status before the disease. Difference scores (maximum possible change +/- 100) revealed a mean reduction of smell (-79.7 +/- 28.7, mean +/- standard deviation), taste (-69.0 +/- 32.6), and chemesthetic (-37.3 +/- 36.2) function during COVID-19. Qualitative changes in olfactory ability (parosmia and phantosmia) were relatively rare and correlated with smell loss. Importantly, perceived nasal obstruction did not account for smell loss. Furthermore, chemosensory impairments were similar between participants in the laboratory test and clinical assessment groups. These results show that COVID-19-associated chemosensory impairment is not limited to smell but also affects taste and chemesthesis.The multimodal impact of COVID-19 and the lack of perceived nasal obstruction suggest that severe acute respiratory syndrome coronavirus strain 2 (SARS-CoV-2) infection may disrupt sensory-neural mechanisms

More than smell - COVID-19 is associated with severe impairment of smell, taste, and chemesthesis

Recent anecdotal and scientific reports have provided evidence of a link between COVID-19 and chemosensory impairments, such as anosmia. However, these reports have downplayed or failed to distinguish potential effects on taste, ignored chemesthesis, and generally lacked quantitative measurements. Here, we report the development, implementation, and initial results of a multilingual, international questionnaire to assess self-reported quantity and quality of perception in 3 distinct chemosensory modalities (smell, taste, and chemesthesis) before and during COVID-19. In the first 11 days after questionnaire launch, 4039 participants (2913 women, 1118 men, and 8 others, aged 19-79) reported a COVID-19 diagnosis either via laboratory tests or clinical assessment. Importantly, smell, taste, and chemesthetic function were each significantly reduced compared to their status before the disease. Difference scores (maximum possible change ±100) revealed a mean reduction of smell (-79.7 ± 28.7, mean ± standard deviation), taste (-69.0 ± 32.6), and chemesthetic (-37.3 ± 36.2) function during COVID-19. Qualitative changes in olfactory ability (parosmia and phantosmia) were relatively rare and correlated with smell loss. Importantly, perceived nasal obstruction did not account for smell loss. Furthermore, chemosensory impairments were similar between participants in the laboratory test and clinical assessment groups. These results show that COVID-19-associated chemosensory impairment is not limited to smell but also affects taste and chemesthesis. The multimodal impact of COVID-19 and the lack of perceived nasal obstruction suggest that severe acute respiratory syndrome coronavirus strain 2 (SARS-CoV-2) infection may disrupt sensory-neural mechanisms. © 2020 The Author(s) 2020. Published by Oxford University Press. All rights reserved

Odor and color of cosmetic products: correlations between subjective judgement and autonomous nervous system response

International audienceThe color and odor of cosmetics have been shown to be crucial for affective states and able to influence autonomic responses. We report an original procedure to measure the effect on subjects of the color and odor of cosmetic products, and to quantify the correlation between objective (psychophysiological recording) and subjective (psychophysics) responses. Several cosmetic products (lipsticks and nail varnishes) of different colors (white, brown, red, orange, and pink) and odors (two per product) were presented. In a first step, autonomous parameters (skin conductance (SC) and heart rate (HR)) were recorded, and in the second step, subjects rated their sensations on subjective scales (overall appreciation, pleasantness, and emotional arousal). Results indicated that certain color and odor additives in cosmetics act on relaxation, excitation, perceived pleasantness, and emotional arousal. It was also found that certain colors, perceived as pleasant, decreased HR, and that the perception of an 'arousing' perfume significantly increased SC

Thought for food: Cognitive influences on chemosensory perceptions and preferences.

Sensory and consumer research often focuses more on bottom-up than top-down influences on consumers\u2019 perception and acceptance of foods. Yet, cognitive processes create and transform incoming sensory information originating from separate senses, including olfaction, gustation, and somatosensation, into the perception of flavour. The present paper discusses five cognitive processes that affect human chemosensory perception and responses to food flavours: Attention, language, memory, learning, and metacognition. It is argued that each of these processes are important in shaping interactions with food via the chemical senses. Attention moderates perception through its distribution across the environment, fine-tuning it for particular stimuli. Interactions among smells, tastes, and textures are acquired through learning, as are hedonic properties. Language affects food acceptability and preference, as does the memory of prior experiences with a food, even when they are not at a conscious level of processing. Metacognitive knowledge of personal capabilities indirectly influences the results of sensory evaluations. Future sensory and consumer research should take into account the significant role that these cognitive factors play in processing incoming chemosensory information

In silico modelling to predict the odor profile of red wines from their molecular composition using experts’ knowledge, fuzzy logic and optimization

International audienc