Philosophiae Doctor - PhD / Tsetse flies are the biological vectors of human and animal trypanosomiasis and hence representant medical and veterinary importance. The sense of smell plays a significant role in tsetse and its ecological interaction, such as finding blood meal source, resting, and larvicidal sites and for mating. Tsetse olfactory behaviour can be exploited for their management; however, olfactory studies in tsetse flies are still fragmentary. Here in my PhD thesis, using scanning electron microscopy, electrophysiology, behaviour, bioinformatics and molecular biology techniques, I have investigated tsetse flies (Glossina fuscipes fuscipes) olfaction using behaviourally well studied odorants, tsetse repellent by comparing with attractant odour. Insect olfaction is mediated by olfactory sensory neurons (OSNs), located in olfactory sensilla, which are cuticular structures exposed to the environment through pore and create a platform for chemical communication. In the sensilla shaft the dendrite of OSNs are housed, which are protected by called the sensillum lymph produced by support cells and contains a variety of olfactory proteins, including the odorant binding protein (OBP) and chemosensory proteins (CSP). While on the dendrite of OSNs are expressed olfactory receptors. In my PhD, studies I tried to decipher the sense of smell in tsetse fly. In the second chapter, I demonstrated that G. f. fuscipes is equipped with diverse olfactory sensilla, that various from basiconic, trichoid and coeloconic. I also demonstrated, there is shape, length, number difference between sensilla types and sexual dimorphism. There is a major difference between male and female, while male has the unique basiconic sensilla, club shaped found in the pits, which is absent from female pits. In my third chapter, I investigated the odorant receptors which are expressed on the dendrite of the olfactory sensory neurons (OSNs). G. f. fuscipes has 42 ORs, which were not functionally characterised. I used behaviourally well studied odorants, tsetse repellents, composed of four components blend. I demonstrated that tsetse repellent is also a strong antifeedant for both G. pallidipes and G. f. fuscipes using feeding bioassays as compared to the attractant odour, adding the value of tsetse repellent. However, the attractant odour enhanced the feeding index. Using DREAM (deorphanization of receptors based on expression alterations of mRNA levels). I found that in G. f. fuscipes, following a short in vivo exposure to the individual tsetse repellent component as well as an attractant volatile chemical, OSNs that respond to these compounds altered their mRNA expression in two opposite direction, significant downregulation and upregulation in their number of transcripts corresponding to the OR that they expressed and interacted with odorant. Also, I found that the odorants with opposite valence already segregate distinctly at the cellular and molecular target at the periphery, which is the reception of odorants by OSNs, which is the basis of sophisticated olfactory behaviour. Deorphanization of ORs in none model insect is a challenge, here by combining DREAM with molecular dynamics, as docking score, physiology and homology modelling with Drosophila a well-studied model insects, I was able to predict putative receptors of the tsetse repellent components and an attractant odour. However, many ORs were neutral, showing they were not activated by the odorants, demonstrating the selectivity of the technique as well as the receptors. In my fourth chapter, I investigated the OBPs structures and their interaction with odorants molecules. I demonstrated that OBPs are expressed both in the antenna, as well as in other tissues, such as legs. I also demonstrated that there are variations in the expression of OBPs between tissues as well as sexes. I also demonstrated that odorants induced a fast alteration in OBP mRNA expression, some odorants induced a decrease in the transcription of genes corresponding to the activated OBP and others increased the expression by many fold in OBPs in live insect, others were neutral after 5 hours of exposure. Moreover, with subsequent behavioural data showed that the behavioural response of G. f. fuscipes toward 1-octen-3-ol decreased significantly when 1-octen-3-ol putative OBPs were silenced with feeding of double-stranded RNA (dsRNA). In summary, our finding whereby odorant exposure affects the OBPs mRNA, their physiochemical properties and the silencing of these OBPs affected the behavioural response demonstrate that the OBPs are involved in odour detection that affect the percept of the given odorant. The expression of OBPs in olfactory tissues, antenna and their interaction with odorant and their effect on behavioural response when silenced shows their direct involvement in odour detection and reception. Furthermore, their expression in other tissues such as legs indicates they might also have role in other physiological functions, such as taste.

The thesis was conducted as the master thesis for a Master's in innovation and design. The aim of this thesis was to investigate in what ways scent can be used as an olfactory stimulation within exhibitions and to access the possible effects that occur from bridging historical contexts with scent within the exhibitions – as a tool for embodied storytelling. The olfactory study focuses on Leksmedjan Smetuna in Rademachersmedjorna, Eskilstuna. The thesis theoretical framework presents theories on sense of smell, museum experiences, storytelling, and embodied storytelling. A space analysis and a qualitative interview with a museum pedagogue at Västermanland´s county museum. An observational smellscape with different scented elements is conducted as well, with visiting children at Leksmedjan Smetuna in Rademachersmedjorna – where children get the chance to experience historical scents from the 17th century, through their sense of smell. This with the aim to visualize the physical-, emotional- and social effects that occur during children´s sensory museum experiences. The scented elements for the observational smellscapes were designed and produced during the thesis design process and are based on theoretical and empirical data collection. The results of the thesis bring forth important perspectives regarding children´s sensory museum experiences that incorporate scented elements. / Examensarbetet genomförs som ett examensarbete för en Master i innovation och design. Syftet med denna studie är att undersöka på vilka sätt doft kan användas som luktstimulering inom utställningar, samt att visualisera möjliga effekter som uppstår genom att överbrygga historiska sammanhang med hjälp av doft inom utställningar – som ett verktyg för embodied storytelling. Doftstudien fokuserar på Leksmedjan Smetuna i Rademachersmedjorna, Eskilstuna. Studiens teoretiska ramverk presenterar teorier om människans luktsinne, museiupplevelser, storytelling med en fördjupning av embodied storytelling. Studiens empiriska metodarbete utgörs av en rumsanalys och en kvalitativ intervju med en museipedagog på Västermanlands länsmuseum. Metodarbetet inkluderar även en observerande smellscapes med besökande barn på Leksmedjan Smetuna i Rademachersmedjorna, Eskilstuna – där barnen får chansen att uppleva historiska dofter från 1600-talet, genom sitt luktsinne. Detta i syfte att visualisera de fysiska-, emotionella- och sociala effekterna som uppstår under barns sensoriska museiupplevelser av studiens doftelement. Doftelementen som ingår i studiens observerade smellscapes, designades och producerades under studiens designprocess och baseras på den teoretisk och empirisk datainsamling. Studiens resultat lyfter fram viktiga perspektiv på barns sensoriska museiupplevelser som innehåller doftelement.

Die vorliegende Studie untersuchte emotionale Reaktionen im Experimentaldesign einer aversiven, differentiellen klassischen Konditionierung (CS = zwei männliche, neutral valente Gesichter; olfaktorischer UCS = vergorene Hefe) bei je vierzehn männlichen generalisierten Sozialphobikern (DSM-VI) und gesunden Kontrollpersonen. In Erwartung einer erhöhten Konditionierbarkeit, einer Extinktionsresistenz sowie einer Generalisierung auf störungsrelevante Fazialreize bei den Sozialphobikern wurden die konditionierten Reaktionen über subjektiv-verbale Urteile (Valenz, Erregung, Kontingenz), den Schreckreflex (M. orbicularis oculi links, Indikator subcorticaler Reizverarbeitung der Angst), die bilateral erhobene Aktivität des M. corrugator supercilii (Indikator für den negativ emotionalen Fazialausdruck) sowie die Herzrate (Indikator der allgemeinen psychophysiologischen Aktivierung) gemessen. Die Konditionierung verlief in beiden Experimentalgruppen erfolgreich (Valenz, Erregung, Kontingenz) und hypothesenkonform. Im Gegensatz zu den Gesunden resultierten für die Sozialphobiker eine erhöhte Konditionierbarkeit (Schreckreflexlatenz und -amplitude, Herzratendezeleration), eine Extinktionsresistenz (Erregung, Schreckreflexnullreaktionen, Corrugator) sowie eine Reizgeneralisierung (Erregung, Kontingenz, Schreckreflexlatenz, Corrugator, Herzratendezeleration). Die Befunde sprechen außerdem für eine unterschiedliche emotionale Reizverarbeitung über den Experimentalverlauf. Die Sozialphobiker reagierten in der Akquisition vorrangig in den Parametern Erregung, Kontingenz, Schreckreflex und Herzrate (Gesunde: Corrugator) sowie in der Extinktion hinsichtlich Erregung, Schreckreflex und Corrugator (Gesunde: Kontingenz). Das Valenzurteil ergab hingegen keine Gruppenspezifik. / The present study investigated the emotional responses of aversive differential Pavlovian conditioning with two male neutral faces as conditioned stimuli (CS) and a foul odor (fermented yeast) as unconditioned stimulus (UCS) in fourteen male generalized social phobics (DSM-VI) and healthy controls. The aim of this investigation was to examine the hypotheses of enhanced acquisition, delayed extinction and generalization of faces, as they represented socially relevant stimuli, concerning social phobics. Subjective indicators of conditioned response were valence, arousal and awareness. The startle reflex (recorded from left m. orbicularis oculi) was used as a measure of subcortical emotional processing. Bilaterally corrugator muscle activity (as an indicator of negative emotional facial response) and heart rate (as an indicator of general physiological activation) served as psychophysiological assessment of conditioning. Both groups were successfully conditioned as reflected by differential responses of all three subjective parameters. The results were consistent with the hypotheses. Compared to controls, social phobics showed an increased acquisition (startle latency and magnitude, heart rate deceleration), an extinction resistance (arousal, startle zero reactions, corrugator) as well as a generalization of CS types (arousal, awareness, startle latency, corrugator, heart rate deceleration). In addition the findings suggested that the emotional stimuli processing in participants are distinct. The social phobics in particular reacted to arousal, contingency awareness, startle and heart rate in acquisition (controls: corrugator) and to arousal, startle and corrugator in extinction (controls: awareness). There was no difference between groups regarding valence judgement.

No description available.

No description available.

No description available.

No description available.

No description available.

Society would tell us that women have a superior sense of smell compared to men, but studies on innate olfactory ability have failed to verify these results. Perhaps women outperform men on some tests of olfactory ability due to the effect of a societal bias on perception, instead. The goal of this study was to determine if the presence of a sex-specific societal bias could affect an individual’s olfactory perception by influencing an individual to both rate an olfactory stimulus in line with the presented bias while also perceiving a noticeable difference according to the bias’s expectations. During both biased and unbiased conditions, 32 adults (women, n =16) were asked to smell and rate a set of 20 flasks all containing the same concentration of butanol. The biased scores were the same for both sexes with only the presentation of the bias changing. Participants were also asked to answer a follow-up survey tasked at determining why they rated to two conditions differently. The results showed that participants tended to rate in line with the sex-specific bias for measures of intensity. No difference for intensity scores were observed between the sexes. All 32 participants marked on the follow-up survey that they rated differently between conditions, with the majority of them indicating that they did perceive the biased condition as more intense. The results from this experiment provide support for the hypothesis that the presence of a societal bias can potentially affect how an individual perceives an olfactory stimulus. / Samhället säger oss att kvinnor har ett bättre luktsinne jämfört med män, men studier på medfödd luktförmåga har misslyckats att verifiera detta. Det är möjligt att kvinnor presterar bättre än män i vissa studier om luktförmåga på grund av fördomar som ändrar deras uppfattning om deras luktförmåga. Målet med denna studie var att avgöra om närvaron av en könsspecifik bias kunde påverka en individs luktuppfattning genom att påverka en individ att skatta en lukt i linje med en bias och samtidigt uppleva en märkvärd skillnad enligt förväntningar från biasen. Under två omgångar, en med och en utan bias, ombads 32 vuxna (kvinnor, n = 16) att lukta och skatta en samling av 20 flaskor där alla innehöll samma koncentration av n-butanol. Biasen var samma för män och kvinnor, där endast presentationen ändrades. Deltagarna ombads också fylla i en uppföljningsenkät med syftet att avgöra varför de skattade de två omgångarna olika. Resultaten visade på att deltagarna tenderade att skatta i linje med den könsspecifika biasen för skattningar av intensitet. Ingen skillnad i värden för intensitet observerades mellan könen. Alla 32 deltagare markerade på uppföljningsenkäten att de skattade olika mellan de två omgångarna, och att majoriteten indikerade att de upplevde lukterna med bias som mer intensiva. Resultaten från detta experiment ger stöd för hypotesen att närvaron av en bias potentiellt kan påverka hur en individ upplever en lukt.

This thesis deals with machine learning techniques for the extraction of structure and the analysis of the vertebrate olfactory pathway based on related methods. Some of its main contributions are summarized below. We have performed a systematic investigation for classification in biomedical images with the goal of recognizing a material in these images by its texture. This investigation included (i) different measures for evaluating the importance of image descriptors (features), (ii) methods to select a feature set based on these evaluations, and (iii) classification algorithms. Image features were evaluated according to their estimated relevance for the classification task and their redundancy with other features. For this purpose, we proposed a framework for relevance and redundancy measures and, within this framework, we proposed two new measures. These were the value difference metric and the fit criterion. Both measures performed well in comparison with other previously used ones for evaluating features. We also proposed a Hopfield network as a method for feature selection, which in experiments gave one of the best results relative to other previously used approaches. We proposed a genetic algorithm for clustering and tested it on several realworld datasets. This genetic algorithm was novel in several ways, including (i) the use of intra-cluster distance as additional optimization criterion, (ii) an annealing procedure, and (iii) adaptation of mutation rates. As opposed to many conventional clustering algorithms, our optimization framework allowed us to use different cluster validation measures including those which do not rely on cluster centroids. We demonstrated the use of the clustering algorithm experimentally with several cluster validity measures as optimization criteria. We compared the performance of our clustering algorithm to that of the often-used fuzzy c-means algorithm on several standard machine learning datasets from the University of California/Urvine (UCI) and obtained good results. The organization of representations in the brain has been observed at several stages of processing to spatially decompose input from the environment into features that are somehow relevant from a behavioral or perceptual standpoint. For the perception of smells, the analysis of such an organization, however, is not as straightforward because of the missing metric. Some studies report spatial clusters for several combinations of physico-chemical properties in the olfactory bulb at the level of the glomeruli. We performed a systematic study of representations based on a dataset of activity-related images comprising more than 350 odorants and covering the whole spatial array of the first synaptic level in the olfactory system. We found clustered representations for several physico-chemical properties. We compared the relevance of these properties to activations and estimated the size of the coding zones. The results confirmed and extended previous studies on olfactory coding for physico-chemical properties. Particularly of interest was the spatial progression by carbon chain that we found. We discussed our estimates of relevance and coding size in the context of processing strategies. We think that the results obtained in this study could guide the search into olfactory coding primitives and the understanding of the stimulus space. In a second study on representations in the olfactory bulb, we grouped odorants together by perceptual categories, such as floral and fruity. By the application of the same statistical methods as in the previous study, we found clustered zones for these categories. Furthermore, we found that distances between spatial representations were related to perceptual differences in humans as reported in the literature. This was possibly the first time that such an analysis had been done. Apart from pointing towards a spatial decomposition by perceptual dimensions, results indicate that distance relationships between representations could be perceptually meaningful. In a third study, we modeled axon convergence from olfactory receptor neurons to the olfactory bulb. Sensory neurons were stimulated by a set of biologically-relevant odors, which were described by a set of physico-chemical properties that covaried with the neural and glomerular population activity in the olfactory bulb. Convergence was mediated by the covariance between olfactory neurons. In our model, we could replicate the formation of glomeruli and concentration coding as reported in the literature, and further, we found that the spatial relationships between representational zones resulting from our model correlated with reported perceptual differences between odor categories. This shows that natural statistics, including similarity of physico-chemical structure of odorants, can give rise to an ordered arrangement of representations at the olfactory bulb level where the distances between representations are perceptually relevant. / <p>QC 20120224</p>