Search results for "Percept"
showing 10 items of 3839 documents
Neonatal representation of odour objects: distinct memories of the whole and its parts
2014
Extraction of relevant information from highly complex environments is a prerequisite to survival. Within odour mixtures, such information is contained in the odours of specific elements or in the mixture configuration perceived as a whole unique odour. For instance, an AB mixture of the element A (ethyl isobutyrate) and the element B (ethyl maltol) generates a configural AB percept in humans and apparently in another species, the rabbit. Here, we examined whether the memory of such a configuration is distinct from the memory of the individual odorants. Taking advantage of the newborn rabbit's ability to learn odour mixtures, we combined behavioural and pharmacological tools to specifically…
Physico-Chemical Interactions in the Flavor-Release Process
2017
The perception of flavor is induced by the release of aroma compounds in the vapor phase. The olfactory perception is not only related to the nature of aroma compounds initially present in the food, but also to their distribution between the different phases. After a description of the interactions established between the aroma compounds and different constituents of food, this chapter looks at physico-chemical characteristics of aroma compounds and at the composition and properties of food matrices. Then, in order to understand the behavior of aroma compounds in the matrices, study methods of interactions are described. The assessment of the release is done by determining the partition coe…
Acute effects of 1,1,1-trichloroethane on human olfactory functioning.
2004
Background Animal experiments indicate that 1,1,1-trichloroethane can cause degeneration of the olfactory epithelium. The effects of 1,1,1-trichloroethane on human odor perception still have not been investigated. The goal of this study was to learn more about acute effects of 1,1,1-trichloroethane. Methods Twelve healthy, nonsmoking students were exposed to 200 and 20 ppm (control) 1,1,1-trichloroethane in an exposure chamber for 4 hours according to a crossover design. Olfactory functioning was investigated with the Sniffin’ Sticks. The test includes the determination of the detection threshold for n-butanol and an odor identification test. Results After 1 hour of exposure to 200 ppm 1,1,…
Expression of Odorant Receptor Family, Type 2 OR in the Aquatic Olfactory Cavity of Amphibian Frog Xenopus tropicalis
2012
International audience; Recent genome wide in silico analyses discovered a new family (type 2 or family H) of odorant receptors (ORs) in teleost fish and frogs. However, since there is no evidence of the expression of these novel OR genes in olfactory sensory neurons (OSN), it remains unknown if type 2 ORs (OR2) function as odorant receptors. In this study, we examined expression of OR2 genes in the frog Xenopus tropicalis. The overall gene expression pattern is highly complex and differs depending on the gene and developmental stage. RT-PCR analysis in larvae showed that all of the OR2η genes we identified were expressed in the peripheral olfactory system and some were detected in the brai…
Perceptual blending in odor mixtures depends on the nature of odorants and human olfactory expertise.
2012
International audience; Our olfactory system is confronted with complex mixtures of odorants, often recognized as single entities due to odor blending (e.g., coffee). In contrast, we are also able to discriminate odors from complex mixtures (e.g., off-odors). Therefore, the olfactory system is able to engage either configural or elemental processes when confronted with mixtures. However, the rules that govern the involvement of these processes during odor perception remain poorly understood. In our first experiment, we examined whether simple odorant mixtures (binary/ternary) could elicit configural perception. Twenty untrained subjects were asked to evaluate the odor typicality of mixtures…
Reduction of olfactory sensitivity during normobaric hypoxia.
2018
Abstract Objective Acute mountain sickness (AMS) is caused by a low partial pressure of oxygen and may occur above 2500 m. The aim of this research was to evaluate olfactory and gustatory abilities of healthy subjects during baseline conditions and after seven hours of normobaric hypoxia. Methods Sixteen healthy subjects were assessed using the Sniffin’ Sticks, as well as intensity and pleasantness ratings. Gustatory function was evaluated utilizing the Taste Strips. Experiments were carried out under baseline conditions (518 m altitude) followed by a second testing session after seven hours of normobaric hypoxia exposure (comparable to 4000 m altitude). Results During normobaric hypoxia ol…
Olfactory function in children assessed with psychophysical and electrophysiological techniques
2007
International audience; The olfactory information processing abilities of children undergo changes during early life. The aims of the present study were to describe these changes and to probe for their electrophysiological correlates. These aims were investigated in two experiments. In Experiment 1, responses of 146 subjects (3-12 years) were tested with psychophysical tools. Approximately 2/3 of the subjects completed the olfactory tests ("Sniffin' Sticks"). In Experiment 2, 12 additional subjects (3-10 years) were tested with electrophysiological tools. Event-related potentials (ERPs) were recorded in response to olfactory stimulation with H(2)S. Results from Experiment 1 indicated that d…
A putative social chemosignal elicits faster cortical responses than perceptually similar odorants.
2006
Social chemosignals, so-called pheromones, have recently attracted much attention in that effects on women's psychophysiology and cortical processing have been reported. We here tested the hypothesis that the human brain would process a putative social chemosignal, the endogenous steroid endrostadienone, faster than other odorants with perceptually matched intensity and hedonic characteristics. Chemosensory event-related potentials (ERP) were recorded in healthy women. ERP analyses indicate that androstadienone was processed significantly faster than the control odorants. Androstadienone elicited shorter latencies for all recorded ERP components but most so for the late positivity. This fin…
Habituation and adaptation to odors in humans
2017
indexation en cours; Habituation, or decreased behavioral response, to odors is created by repeated exposure and several detailed characteristics, whereas adaptation relates to the neural processes that constitute this decrease in a behavioral response. As with all senses, the olfactory system continually encounters an enormous variety of odorants which is why mechanisms must exist to segment them and respond to changes. Although most olfactory habitation studies have focused on animal models, this non-systematic review provides an overview of olfactory habituation and adaptation in humans, and techniques that have been used to measure them. Thus far, psychophysics in combination with moder…
Perceived Onset Time of Medical Conditions: The Interplay Between Subjective Fear and Risk in Four Lifestyle Domains
2022
Engaging in unhealthy behaviors (e.g., smoking, drinking) and not engaging in healthy ones (e.g., exercising, consuming fruit and vegetables) are both relatively prevalent among individuals despite the available information about their risks for health. People’s perception of an event’s time course can be used to gauge their risk perception for that event thus casting light on any possible misperception and suggesting directions for health-promoting interventions. This study investigates people’s perception of the time of onset of 5 noncommunicable diseases (e.g., “having high blood pressure”) associated with 4 health-related behaviors: Smoking, drinking, exercising, and eating fruit and v…