Comparative Fear-Related Behaviors to Predator Odors (TMT and Natural Fox Feces) before and after Intranasal ZnSO4 Treatment in Mice

The possibility that synthetic 2,4,5-trimethylthiazoline (TMT), frequently used to induce unconditioned fear in rodents, could be more a pungent odor activating intranasal trigeminal nerve fibers rather than a predator odor index is currently discussed. In order to explore this question, the present study compared fear-related behaviors to predator odors (synthetic 10% TMT and natural fox feces) and toluene (as an irritant compound without ecological significance) before and after intranasal ZnSO4 perfusion which is known to provoke transient anosmia. Results show that natural fox feces could be consider as a pure olfactory (CN I) nerve stimulant while 10% TMT appeared to be a mixed olfactory (CN I) and trigeminal (CN V) nerves stimulant with a great olfactory power and a low trigeminal power. These findings suggest that behavioral neuroscience studies should use concentrations lower than 10% TMT to obtain fear-related behaviors similar to those obtained with natural fox feces odor

Odor Hedonic Profile (OHP): a self-rating tool of everyday odors

Odor hedonic estimation (pleasant/unpleasant) is considered the first and one of the most important dimensions in odor perception. Although there are several published scales that rate odor hedonicity, most of them use odorants that induce biases related to stimulus properties or test conditions and make difficult clinical or industrial applications. Thus, this study aimed to propose a model of odor hedonic profile (OHP) based on 14 items related to everyday odors without stimulus. The OHP is a self-rating tool based on the hedonic estimate representation and allows the determination of specific profiles, i.e., “conservative,” “neutral,” “liberal,” “negative olfactory alliesthesia,” and “positive olfactory alliesthesia.” It can be useful in different contexts (e.g., food studies) and general pathologies (e.g., eating disorders) or pathologies with mood/emotional disturbances (e.g., depression)

New genetic loci link adipose and insulin biology to body fat distribution.

Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms

A la découverte des odeurs

International audienceOften taken for granted, the sense of smell has seldom been discussed or understood. However, since the start of the 20th Century, studies in this area have grown exponentially and today there is a greater understanding of the olfactory system – at both structural and functional levels. Scientists now concern themselves with questions about the holistic nature of our sense of smell and are investigating the role of odors in interpersonal relations, in food intake processes, in the diagnosis of certain illnesses, and many other areas. The beginnings of this knowledge are as fascinating as they are abundant and numerous disciplines are involved: psychology, physiology, genetics, neuroscience, engineering, etc. This book illustrates and analyzes the current state of advances in research about the smells around us, and the way in which they influence our relationship with the world

Olfactory/trigeminal interactions in nasal chemoreception.

International audienceFor a long time, studies devoted to intranasal chemoreception have separately considered the different systems which coexist in the human nasal cavity, especially the olfactory and trigeminal systems. For the former, the findings have contributed to a better understanding of transduction, perception and the treatment of odors. For the latter, data have contributed to the knowledge of somatosensory innervation into the nose, especially in relation to nociception. During the last two decades, an increasing number of studies focused on interactions occurring between both systems. Indeed, most odorant molecules have the propensity to simultaneously stimulate olfactory and trigeminal systems in the nasal cavity. The interactions between both systems appear complex and take place at peripheral, central or perceptual levels. Studies in neurobiology, electrophysiology, psychophysics or functional imaging contribute to determine how both olfactory and trigeminal systems coexist and how one system could influence the other in the treatment of sensory information. However, several structural, functional and methodological questions remain unsolved in the field of olfactory/trigeminal interactions and deserve further research

Dispositif pour évaluer la perception olfactive

La présente invention concerne un dispositif (1) pour évaluer la perception olfactive d'un utilisateur, comportant : - un support (2) mobile relativement à l'utilisateur, - une pluralité de réservoirs contenant des substances odorantes, portée par le support (2), - des obturateurs fermant les réservoirs, - un mécanisme de déplacement (6) du support (2) relativement à l'utilisateur permettant d'amener sélectivement un réservoir en position de test devant l'utilisateur, et lui permettant d'inspirer la substance odorante (Sj) contenue dans ledit réservoir, - un système de détection (8) délivrant une information relative à la respiration de l'utilisateur, - un système de commande (9) pour agir sur le mécanisme de déplacement (6) afin d'amener successivement plusieurs réservoirs dans la position de test et de permettre à l'utilisateur d'inspirer successivement les substances odorantes contenues dans ces réservoirs, le fonctionnement du mécanisme de déplacement (6) s'effectuant en fonction de l'information délivrée par le système de détection (8) au système de commande (9)

L'odorat des animaux: Performances et adaptations

International audienceChez beaucoup d’espèces animales, les stimuli chimio-sensoriels et les stimuli olfactifs en particulier, jouent un grand rôle dans le contrôle et la régulation des comportements fondamentaux : marquage du territoire, repérage et circulation dans l’espace, recherche de nourriture et comportements alimentaires, comportements sociaux et reconnaissance interindividuelle, comportements sexuels et reproducteurs, comportements d’évitement de toutes formes de danger. Aussi, l’odorat des animaux constitue-t-il un modèle d’étude pour de nombreuses disciplines scientifiques (génétique, neurobiologie, sciences cognitives, éthologie…). En outre, interface entre les organismes et leur milieu, le système olfactif s’avère particulièrement exposé aux changements climatiques et aux pollutions de toutes natures, contribuant de fait à la vulnérabilité de certains écosystèmes. Balayant le large spectre du règne animal (et parfois même au-delà), l’objectif de cet ouvrage est d’éclairer dans chaque paragraphe, un aspect spécifique du système olfactif (Une histoire de...) à travers le prisme d’une espèce particulière (Le nez de...) en référence à des études ad hoc, pour la plupart très récentes

L'olfaction dans les troubles dépressifs : intérêts et perspectives

International audienceResearch on sensorial interactions with psychiatric diseases and particularly with the depressive syndrome has mainly focused on visual or auditory processes and much less on olfaction. The depressive illness is one of the most frequent psychiatric diagnoses in the community, with approximately one in five women and one in eight men experiencing a major depressive episode during their lifetime. Although genetic, epigenetic, neuroanatomical, neurochemical, neuroendocrinological and neuroimmunological changes can be detected during depression, the etiology of depression remains partly unclear. The current explanatory models are based on two main factors, i.e. pharmacological dysfunctions and stress effects. In this way and because of strong connections between olfactory pathways and cerebral areas implied in mood regulation and emotions (i.e. the limbic system and prefrontal areas), the interactions between olfaction and depression could constitute a relevant way of research at three different levels. First, olfactory dysfunction observed in depression could serve the diagnosis and contribute to a better understanding of mechanisms implied in thymic pathologies. Published papers show a decrease of olfactory sensitivity in major depression which does not occur in bipolar or saisonal depression. Second, it has been shown that olfactory deficits could induce depressive symptoms. In this context, an animal model (olfactory bulbectomized rat) reinforces the hypothesis of the important role of olfaction in depression based on neuroanatomical and neurochemical observations. Third, several publications have demonstrated that odors can positively impact the depressive mood. Thus, a remediation by odors in depression appears to be a promising way. From several decades, the olfaction/depression interactions have been covered by a broad literature. Thus, the present review will not propose an exhaustive examination but aims to point out the most recently published papers and highlight their contributions to the understanding of olfactory processes implied in depression.Il existe une abondante littérature, depuis plusieurs décennies, sur les liens entre olfaction et dépression. La revue de la littérature proposée ici n'a donc pas vocation à être exhaustive sur les travaux publiés mais vise plutôt à mettre en exergue les études les plus récentes et leurs apports à la compréhension des mécanismes olfactifs dans la dépression. En effet, étant donné l'existence de connexions étroites entre voies olfactives et aires cérébrales impliquées dans la régulation de l'humeur et des émotions (notamment au niveau du système limbique et des aires préfrontales), l'olfaction constitue une voie de recherche intéressante et novatrice à de nombreux égards. En premier lieu, l'étude des troubles olfactifs occurrents dans la dépression peut aider au diagnostic et surtout à la compréhension des mécanismes sous-jacents aux troubles thymiques. Les travaux publiés révèlent que l'épisode dépressif caractérisé est associé à une réduction de la sensibilité olfactive, ce qui n'est pas retrouvé dans la dépression bipolaire et la dépression saisonnière. En second lieu, il a été montré que des déficits de perception des odeurs pouvaient être à l'origine de symptômes dépressifs. Les corrélats neuro-anatomiques et neurochimiques plaident assez clairement pour un effet causal de la perte olfactive sur les troubles de l'humeur en général et, dans ce contexte, un modèle animal (rat bulbectomisé) conforte l'hypothèse du rôle non négligeable de l'olfaction dans les troubles dépressifs. En troisième lieu, plusieurs travaux tendent à prouver que les odeurs peuvent potentiellement avoir un impact sur l'amélioration des états dépressifs. Une remédiation par l'utilisation d'odeurs dans les troubles dépressifs et anxieux est une voie de recherche prometteuse, notamment du fait de l'impact sur le fonctionnement neurochimique de la dépression qui semble démontré chez l'animal

Lateralisation in wine olfactory threshold detection: Comparison between experts and novices.

International audienceThe study of olfactory lateralisation in humans has given rise to many publications, but few studies have been focused on possible differences in relation to the experience towards specific odorants. The aim of the present study was to compare unilateral detection thresholds for three wines between expert and novice judges. Additionally, irritation and hedonic valence were also evaluated using monorhinal stimulations. Results showed that the novices had lower detection thresholds with the left nostril-whatever the wine-compared to the experts. Concerning hedonic rating, no nostril difference existed in the expert group contrary to the novice group, which evaluated wines as more pleasant with the left than with the right nostril. Irritation rating appeared not to be lateralised in both groups. However, the novices rated the three wines as more irritant than the experts with the right as well as with the left nostril. These findings suggest that the level of experience induced specific differences in terms of lateralisation between wine experts and novices