Certaines études ont montré que des odeurs subliminales – odeurs d'intensité très faible activant le système olfactif mais non perçues consciemment – peuvent impacter le comportement alimentaire. Cependant, les mécanismes sensoriels et cognitifs impliqués dans le traitement des odeurs subliminales demeurent mal connus. Ce travail de thèse avait pour but d'explorer les activations cérébrales induites par des odeurs subliminales au moyen de l'Imagerie par Résonance Magnétique fonctionnelle. Durant les acquisitions IRM, les participants sont exposés à leur insu à deux odeurs présentées à intensité subliminale puis supraliminale. Quatre réseaux cérébraux mis en évidence par Analyse en Composantes Indépendantes s’avèrent spécifiques de la condition subliminale. Ces réseaux ne sont pas propres au traitement des odeurs et semblent liés à des processus attentionnels et de contrôle exécutif. La modulation de leur activité par des odeurs subliminales apporte des éléments nouveaux pour comprendre l’impact de ces odeurs sur le comportement, et suggère des applications possibles d'utilisation de ces odeurs pour réguler le comportement alimentaire. / Some studies showed that subliminal odours – odours of very low intensity which activate the olfactory system but are not consciously perceived – can impact food behaviours. However, the sensory and cognitive mechanisms involved in subliminal odours processing remain poorly known. This work aims exploring cerebral activity induced by subliminal odours by the means of functional Magnetic Resonance Imaging. During MRI acquisitions, participants were unknowingly exposed to two odours presented at subliminal intensity and then at supraliminal intensity. Four cerebral networks highlighted by Independent Component Analysis (ICA) prove to be specific to the subliminal condition. These networks are not particular to olfactory processing and seem to be linked to attentional and executive control processes. The modulation of their activity by subliminal odours brings new elements to understand the impact of these odours on behaviour, and suggests possible applications for using these odours to regulate food behaviour.

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Le discours olfactif en France se conclue par la subjectivité individuelle et la relativité culturelle : tout individu comme toute culture développe son penchant olfactif différencié. La problématique consiste à étudier si la personnalité autocontrainte et égocentrique de l'individu moderne explique la formation du récit, et si le déséquilibre de la personnalité moderne est dû à l'ascension inaccessible au pouvoir dans la société égalitaire et étatique de nation centralisée et monopolisée en concurrence avec la société globalisée du marché. L'approche comparative tente d'explorer la diversité et la généralité de cette personnalité autocontrainte et égocentrique, et si la dimension relativiste du récit est une expression nationale française et/ou universaliste eurocentrique. Les études empiriques appuyées sur la société du parfumeur français démontrent que la différenciation personnalisée individualise la sensibilité olfactive ; celles appuyées sur la société du maître de l'art de l'encens au Japon illustrent que la différenciation individuelle est l'expérience social générale, mais se démarque par le processus de la formation de l'état-nation. L'expérience de ce processus au Japon ne correspond pas entièrement aux hypothèses éliasiennes ; l'influence de l'occidentalisation ne configure pas de la même manière l'individualité que l'européanisation ou la colonisation. L'hypothèse éliasienne que le soi à autrui de l'individu-joueur, d'après le modèle de jeux, anticipe son avenir, est une théorisation de généralité mais objectivée de l'expérience de la formation étatique en Europe Occidental.

No description available.

La plupart des études sur la perception isolent une modalité sensorielle pour mieux l’étudier et la comprendre. Malheureusement, aucun de nos sens ne représente la seule source d’information, car une intégration sensorielle se fait en tout moment lors de la perception de l’environnement. L’information d’un sens est donc plutôt en accord ou en conflit avec l’apport d’information des autres sens. Le but de la présente étude était d’investiguer, par IRMf, les activations cérébrales d’une intégration visuelle et olfactive lorsque ces deux perceptions sont congruentes. Pour ce faire, une image et/ou une odeur étaient présentées au sujet et ce dernier devait identifier si le stimulus perçu était congruent. Ce protocole permettait d’observer les activations cérébrales lors de l’analyse d’un stimulus et la prise de décision selon la congruité du stimulus présenté. La condition de congruence vision-odeur activa les zones visuelles et olfactives plus fortement que lors des conditions contrôle (image seule, odeur seule). Ces résultats illustrent une potentialisation des aires visuelles et olfactives par une intégration d’information congruente venant de ces deux modalités. Par conséquent, l’intégration d’un stimulus visuel et odorant congruent semble rehausser la perception du stimulus. / Most studies on perception isolate one sensory modality in order to better study and comprehend it. Unfortunately, none of our senses represents the only source of information, since sensory integration is underway at all times during environmental perception. The information from one sense is therefore usually in agreement with or in conflict with the input of information from other senses. The goal of the present study was to investigate, by fMRI, the cerebral activations caused by visual and olfactory integration when these two perceptions are congruent. To do this, an image and/or an odour were presented to the subject who then had the task of identifying whether the perceived stimulus was congruent. This protocol allowed the observation of the cerebral activations during stimulus analysis and decision-making depending on the congruity of the presented stimulus. The vision-odour congruent condition activated the visual and olfactory areas more strongly than the control conditions (image only, odour only). These results illustrate a potentialization of the visual and olfactory areas by an integration of the congruent information coming from these two modalities. As a result, the integration of a visual and olfactory congruent stimulus seems to enhance the perception of a stimulus.

Dans le système olfactif des moustiques, les protéines liants les molécules odorantes ou odorant binding proteins (OBPs) interviennent dans les toutes premières étapes permettant d'aboutir à la reconnaissance de leurs hôtes et font l'objet d'un intérêt croissant dans les recherches sur la transmission des maladies infectieuses par ces insectes. Le travail présenté a pour objet d'approfondir les connaissances sur ces OBPs dans trois génomes de moustiques, tous vecteurs de maladies infectieuses : Anopheles gambiae, Aedes aegypti et Culex quinquefasciatus. Une analyse à l'échelle de ces génomes a été réalisée et a permis d'identifier un nombre important de nouveaux gènes d'OBPs notamment chez les espèces de moustiques Aedes aegypti et Culex quinquefasciatus. Complétée par une étude phylogénétique du répertoire complet de ces gènes dans les trois génomes étudiés, cette analyse a permis d'établir une nouvelle classification des sous familles des OBPs. Ce résultat démontre l'extraordinaire multiplicité et diversité des gènes impliqués dans l'olfaction chez ces espèces de moustiques tout en mettant en lumière certaines propriétés des séquences des OBPs qui sont hautement conservés chez les moustiques. Grâce à la disponibilité de certaines structures d'OBPs de moustiques ou d'autres insectes apparentées, des modèles structuraux de tous les OBPs de la sous famille dites Classic dans les trois génomes, soit au total 137 structures, ont été construits. Ces structures ont servi de base pour le criblage à grande échelle par docking moléculaire d'une chimiothèque de 126 molécules odorantes connues pour leurs propriétés attractives ou répulsives vis-à-vis des moustiques. Ces résultats fournissent pour la première fois, les bases structurales et fonctionnelles pour la compréhension au niveau moléculaire de l'efficacité de certains agents répulsifs tout comme de l'attractivité de certains agents provenant des émanations humaines. Par simulation de dynamique moléculaire, les changements qui s'opèrent dans une de ces OBPs lorsque celle ci, liée à une molécule odorante, se retrouve dans des conditions de pH modifiée ont été caractérisée et un mécanisme probable par lequel ces OBPs participeraient à la reconnaissance et la libération des molécules odorantes est proposée. Cette thèse fournit des éléments de réponses importants quant à la caractérisation génomique, structurale et fonctionnelle des OBPs de moustiques et peut servir de base de départ pour des recherches expérimentales plus approfondies sur ces aspects. / The role of odorant binding proteins in the olfaction of mosquitoes, the primary mechanism of human host recognition, has been an important focus of biological research in the field of infectious disease transmission by these insects. This thesis provides an in depth knowledge of these proteins in three mosquito species Anopheles gambiae, Aedes aegypti and Culex quinquefasciatus. A large scale analysis on these genomes has been carried out towards the identification of the odorant binding proteins in the mosquito genomes. Identification of many new OBP members, in particular in the Aedes aegypti and Culex quinquefasciatus species, and an extensive phylogenetic analysis presenting a novel classification of the OBP subfamilies of these mosquito species has been proposed. This results further demonstrates the extraordinary multiplicity and diversity of the OBP gene repertoire in these three mosquito genomes and highlights the striking sequence features that are nevertheless highly conserved across all mosquito OBPs. Owing to the availability of homologous structures from mosquitoes or related species, the 3D structure modelling of all the Classic OBPs from the three genomes (representing in total 137 structures) has been performed. This was completed by large scale docking studies on these structures by screening a large set of compounds that are known to be mosquito attractants or repellents. These provide many exciting new insights into the structural and functional aspects towards understanding the efficacy of some repellents and of some attractants from human emanations. Through molecular dynamics simulation, the structural changes observed in an OBP bounded to an odorant when pH conditions are modified were characterized and the probable mechanism of ligand binding and release is presented. This work provides the first insights to many of the long awaited questions on the genomic, structural and functional characterization of mosquito OBPs and can be viewed as a reliable starting point for further experimental research focussed on these aspects.

<p> Though it is well established that insects are attracted to decomposing vertebrates, little is known about the mechanism of attraction. Olfaction is thought to be the primary sense involved in resource location by necrophilous insects, and several studies have attempted to identify cadaveric-produced volatile organic compounds (VOCs) that contribute to insect attraction. This previous research has been completed almost exclusively in lab settings, with no field studies to verify these findings. </p><p> The goal of my thesis was to test necrophilous insect attraction to nine cadaveric VOCs (1-butanol, 1-pentanol, <i>p­</i>-xylene, <i>o</i>-xylene, ethanol, cyclohexanone, acetamide, dimethyl disulfide, and dimethyl trisulfide) in a field setting. Pitfall traps at six research locations were baited with the chemicals for one week. Specimens collected from the traps were identified and species assemblages were compared to those of a pig carcass. Replicates were conducted in fall 2018 and spring 2019. </p><p> Two chemicals were identified as important attractants for a variety of necrophilous insects: dimethyl disulfide and dimethyl trisulfide. These chemicals were especially attractive to <i>Phormia regina</i>, a blow fly (Diptera: Calliphoridae) found worldwide. VOC insect communities did not include all of the insects found on carcasses, possibly indicating the necessity of chemical blends for effective attraction. This study is only the second study to test necrophilous insect attraction in a field setting. </p>

Os odores são detectados por uma grande família de receptores olfatórios (ORs) que são expressos nos neurônios olfatórios localizados no nariz. Os ORs ativados por um determinado odor acoplam-se à proteína Galfaolf que irá promover a ativação da adenilil ciclase III, resultando na produção de AMPc. O aumento da concentração de AMPc irá ativar canais iônicos dependentes de AMPc, tendo como consequência a despolarização do neurônio olfatório. A informação desencadeada pela ativação de determinados ORs é então transmitida para regiões específicas do cérebro promovendo a percepção do odor. A determinação da especificidade dos ORs para diferentes odores irá contribuir para o entendimento de como os odores são discriminados pelo sistema olfatório, entretanto, poucos ORs tiveram seus ligantes definidos devido a dificuldade de expressão funcional de ORs em sistema heterólogo. Em nosso trabalho, utilizamos o sistema de duplo-híbrido em levedura a fim de determinar potenciais novos reguladores para Galfaolf. Deste experimento, identificamos que Ric-8B (Ric, abreviatura de Resistant to Inhibitors of Cholinesterase), um provável GEF (GTP Exchange Factor), é capaz de interagir com Gaolf. Assim como Gaolf, Ric-8B é predominantemente expresso nos neurônios olfatórios maduros e em regiões específicas do cérebro. A restrita co-localização de Gaolf e Ric-8B fortemente indica que Ric-8B é uma proteína que participa da via de transdução de sinal de Galfaolf. Através de nossos ensaios, utilizando células HEK-293, foi possível mostrar que Ric-8B é capaz de potencializar a atividade de Galfaolf, tendo como consequência o aumento da produção de AMPc em sistema heterólogo. Por fim, nós mostramos que Ric-8B é capaz de promover a expressão funcional de ORs em sistema heterólogo. Nossos resultados demonstram que a expressão de Ric-8B é capaz de aumentar o acúmulo de Galfaolf na periferia de células HEK-293T, indicando que Ric-8B promove a expressão funcional de ORs provavelmente através da melhora da eficiência do acoplamento dos ORs com Galfaolf. Nossos resultados demonstram que o uso de Ric-8B em um sistema em larga escala irá permitir a expressão funcional de diversos ORs, permitindo a identificação de seus respectivos ligantes. Tal análise irá contribuir para o melhor entendimento do mecanismo de percepção dos odores. / Odorants are detected by a large family of odorant receptors (ORs) expressed in the olfactory neurons in the nose. The activated receptors couple to an olfactory-specific G-protein (Galphaolf), which activates adenylyl cyclase III to produce cAMP. Increased cAMP levels activate cyclic nucleotide-gated channels, causing cell membrane depolarization. The information provided by the odorant receptors is transmitted to specific regions of the brain leading to odorant perception. The determination of the odorant specificities of the different ORs will contribute to the understanding of how odorants are discriminated by the olfactory system. However, only a few ORs have been linked to odorants they recognized to date because ORs are not efficiently expressed in heterologous cells since they are poorly expressed on the cell surface. Here we used yeast two-hybrid to search for potential regulators for Galphaolf. We found that Ric-8B (for Resistant to Inhibitors of Cholinesterase), a putative GTP exchange factor, is able to interact with Gaolf. Like Gaolf, Ric-8B is predominantly expressed in the mature olfactory sensory neurons and also in a few regions in the brain. The highly restricted and colocalized expression patterns of Ric-8B and Galphaolf strongly indicate that Ric-8B is a functional partner for Galphaolf. We show that Ric-8B is able to potentiate Galphaolf-dependent cAMP accumulation in human embryonic kidney 293 cells and therefore may be an important component for odorant signal transduction. Finally, we show that Ric-8B promotes efficient heterologous expression of ORs. Our results show that Ric-8B enhances accumulation of Galphaolf at the cell cortex, indicating that it promotes functional OR expression probably by improving the efficiency of OR coupling to Galphaolf. Our results demonstrate that the employment of Ric-8B in a high-throughput system will allow the functional screening of the OR family members and thereby provide further insight into the mechanisms of odor perception.

RIC-8B é uma proteína que apresenta, in vitro, atividade de fator de troca de nucleotídeos guanina (GEF). No entanto, seu papel in vivo não é conhecido. Dados anteriores do nosso laboratório demonstraram que essa proteína interage especificamente com G&#945;olf, que é uma proteína G exclusiva do sistema olfatório, presente nos cílios dos neurônios olfatórios, onde ocorre a transdução de sinal ativada pelos odorantes. No camundongo adulto verificou-se, por meio de ensaios de hibridização in situ, que RIC-8B está presente somente em regiões de expressão de G&#945;olf: no epitélio olfatório maduro e no núcleo estriado do sistema nervoso central. Para avaliar a função fisiológica de RIC-8B in vivo, resolvemos gerar uma linhagem de camundongo knockout para Ric-8B. Verificamos que a linhagem é inviável devido à letalidade dos embriões já em fases precoces do desenvolvimento (por volta de E8,5 e E9,0). A coloração de embriões com X-gal mostra que RIC-8B é especificamente expressa em regiões que darão origem ao sistema nervoso, como na região ventral do tubo neural, e em regiões cefálicas. Interessantemente, mostramos que RIC-8B é expressa na placa do assoalho do tubo neural, de uma maneira muito semelhante ao padrão de expressão de Sonic Hedgehog (SHH), que apresenta um papel fundamental para a organização do sistema nervoso, entre outras funções. Nossos resultados indicam, portanto, que RIC-8B desempenha um papel crucial durante a embriogênese, e que este papel pode estar relacionado com o papel exercido por SHH. Além disso, como a via de sinalização de SHH ocorre em cílios primários nas células alvo, nossos dados levantam a interessante possibilidade de que RIC-8B apresenta funções relacionadas a cílios, tanto no camundongo adulto (neste caso nos cílios dos neurônios olfatórios) como no embrião (neste caso nos cílios primários). / RIC-8B is a protein that, in vitro, acts as a guanine nucleotide exchange factor (GEF). However, its role in vivo remains unknown. Previous data from our laboratory demonstrated that this protein is able to interact specifically with G&#945;olf, a G protein found only in the olfactory system. This G protein is located in the cilia from olfactory neurons, where odorant signaling occurs. In situ hybridization experiments showed that RIC-8B, in adult mice, is expressed only in regions where G&#945;olf is expressed, such as the olfactory epithelium and the nucleus striatum in the central nervous system. In order to determine the function of RIC-8B in vivo, we decided to generate a knockout mouse strain for Ric-8B. We found that this strain is not viable due to the lethality of embryos in the early stages of development (around days E8.5 and E9.0). X-gal staining of embryos shows that RIC-8B is specifically expressed in regions that originate the nervous system, such as the ventral neural tube and also cephalic regions. Interestingly, we show that RIC-8B is restrictedly expressed in the floor plate of the neural tube, in a pattern that is very similar to the one shown by Sonic Hedgehog (SHH). The SHH protein plays a fundamental role in the organization of the nervous system, among other functions. Therefore, our results indicate that RIC-8B plays an essential role during the embryogenesis, and that this role can be related to the role played by SHH. Furthermore, because the SHH signaling pathway occurs in primary cilia in the target cells, our data raise the interesting possibility that the role played by RIC-8B is related to ciliary functions, both in adult mice (in this case, in olfactory cilia), and in the embryo (in this case, in primary cilia)

The chronically ill participants in this study are vulnerable experts in life’s uncertainties, and have become aware over time of multiple medical and social needs and practices. But, unlike the hypo-aware respondents documented in some studies of diabetes mellitus Type 1, these research participants are also conscious of their inability to recognise when their own fluctuating blood glucose levels are rising or falling to extremes, a loss of hyper- or hypo-awareness that puts their lives constantly at risk. Particular sources of better life management, increased self-esteem and means of social (re-)integration are trained medical alert assistance dogs who share the human home, and through keen olfactory sensitivity, are able to give advance warning when their partners’ blood sugar levels enter ‘danger’ zones. Research studies in anthrozoology and anthropology provide extensive literature on historic and contemporary human bonds with domestic and/or wild nonhuman animals. Equally, the sociology of health and illness continues to extend research into care practices performed to assist people with chronic illness. This study draws from these disciplines in order to add to multispecies ethnographic literature by exploring human-canine engagement, contribution and narrative, detailing the impact each member of the dyad has on the other, and by observing the 'doing' of the partnerships' daily routines to ward off hypo-glycaemia and hospitalisation. In addition, the project investigates the place, role and 'otherness' of a medical alert dog in a chronically ill person's understanding of 'the-body-they-do'. The perspective of symbolic interactionism assists in disentangling individual and shared meanings inherent in the interspecies collaboration by examining the mutualistic practices of care performed. The often-flexible moral boundaries that humans construct to differentiate between acceptable use and unacceptable exploitation of nonhuman animals are questioned within ethics-of-care theory, based on the concept of dogs as animate instruments and biomedical resources.