Habituation is a filter that optimizes the processing of information by our brain in all sensory modalities. It results in an unconscious reduced responsiveness to continuous or repetitive stimulation. In olfaction, the main question is whether habituation works the same way for any odorant or whether we habituate differently to each odorant? In particular, whether chemical, physical or perceptual cues can limit or increase habituation. To test this, the odour intensity of 32 odorants differing in physicochemical characteristics was rated by 58 participants continuously during 120s. Each odorant was delivered at a constant concentration. Results showed odorants differed significantly in habituation, highlighting the multifactoriality of habituation. Additionally habituation was predicted from 15 physico-chemical and perceptual characteristics of the odorants. The analysis highlighted the importance of trigeminality which is highly correlated to intensity and pleasantness. The vapour pressure, the molecular weight, the Odor Activity Value (OAV) and the number of double bonds mostly contributed to the modulation of habituation. Moreover, length of the carbon chain, number of conformers and hydrophobicity contributed to a lesser extent to the modulation of habituation. These results highlight new principles involved in the fundamental process of habituation, notably trigeminality and the physicochemical characteristics associated.

Plusieurs illusions tactiles suggèrent que la temporalité des stimulations cutanées dans une séquence modifie leur perception spatiale. S’ils sont assez proches dans l’espace, plus l’intervalle temporel entre deux stimuli est court, plus la distance perçue entre eux est courte. Lorsque les deux stimuli sont présentés simultanément, on observe une perception fusionnée, unique et centrée entre les positions réelles. Ainsi, le système de perception tactile semble utiliser le temps entre les stimuli pour estimer l’espace qui les sépare. Dans l’optique de comprendre comment cette règle perceptive est implémentée dans le système nerveux, nous avons étudié la représentation corticale des stimulations qui induisent ces illusions. Nous avons recherché les distorsions spatiales de la représentation somatotopique dans le cortex somesthésique primaire, à la suite de l’application séquentielle ou simultanée d’une paire de stimuli cutanés sur l’extrémité des phalanges distales de la patte antérieure chez le rat anesthésié. Avec des enregistrements électrophysiologiques et d’imagerie optique extrinsèque, nous avons mis en évidence un phénomène de fusion corticale des entrées sensorielles simultanées, avec un patron spatial d’activation unimodal, centré entre les représentations individuelles des doigts adjacents costimulés. Dans le cas de stimuli successifs, nous avons observé des modifications des réponses au deuxième stimulus dépendantes de l’intervalle inter stimuli. Cette intégration spatiotemporelle ne semble pas contribuer directement au raccourcissement des distances perçues, mais pourrait favoriser les erreurs de localisation constatées lors de la perception des illusions. / Several tactile spatiotemporal illusions suggest that the timing of successive cutaneous stimulations modify the perception of their spatial location. If they are close enough in time and space, shorter inter-stimuli time intervals (ISI) lead to shorted perceived distances. To the extreme of this time-space relation, when the stimuli are simultaneous, subjects report the merged perception of a unique and centered point of stimulation. Therefore, the tactile perceptual system seems to use the time separating two stimuli to compute their spatial distance. To understand the implementation of this perceptual rule, one can investigate the neural representation of the stimuli that elicit the illusory percept, looking for spatial distortions and their underlying mechanisms. Studies based on the measure of the hemodynamic responses have shown such distortions of the somatotopic representations in the primary somatosensory cortex, for simultaneous and delayed stimulations. In order to enhance our understanding of the elementary phenomenon that underpins those spatial modifications of the sensory inputs, we investigated the cortical representation of pairs of simultaneous and delayed cutaneous stimuli in the S1 of anesthetized rats. Using electrophysiological recordings and extrinsic optical imaging, we revealed the cortical merging of inputs from simultaneous digits stimulation. When the stimuli were delayed, we observed ISI-dependent modulations of the responses to the second stimulus. This spatiotemporal integration, that didn’t seem to contribute directly to a distance contraction effect, could however favor the mislocalization observed in illusory perception.

OF DIPLOMA THESIS Author: Bc. Veronika Husovská Supervisor: Mgr. Petra Dvořáková Title: Standardized assessment of sensory disorders in school aged children Summary: The thesis deals with problems of sensory processing disorders in school aged children. The aim of this diploma thesis is to create a working version of the standardized questionnaire Sensory Profile 2 School companion. Another aim is to verify the clinical applicability of this standardized questionnaire by using it to do a screening on school aged children to identify those with a sensory processing disorder within the classroom. The theoretical part of the thesis is focused on the diagnosis of sensory processing disorders (SPD), their diagnostics and the roles of an occupational therapist in SPD. Diagnostic tools for detecting SPD are presented and described in the thesis. The standardized questionnaire Sensory Profile 2, mainly the category School companion, is presented in this thesis. Methods: The practical part of the diploma thesis is elaborated in the form of quantitative pre-research. 39 respondents were evaluated by a standardized questionnaire Sensory Profile 2 School companion for the purpose of pre-research. The respondents were chosen in accordance to the tests purpose. Respondents were third-grade students studying...

Studiens syfte var att få en fördjupad förståelse för hur högkänsliga personer upplever att personlighetsdraget påverkar olika relationer och sociala situationer i dagens sociala samhälle. Data samlades in genom semistrukturerade intervjuer med nio personer som definierar sig som högkänsliga. Informanternas svar analyserades sedan i en tematisk analys för att få fram en överblick över deras upplevelser. Resultatet indikerar att personlighetsdraget påverkar relationerna med andra på många olika sätt, bland annat genom högkänsligas förmåga att läsa av andra, deras djupa bearbetning och deras behov av att undvika överstimulering. Det framkom även att högkänsligas egenskaper inte alltid accepteras eller förstås av omgivningen. / The aim of this study was to get an immersed understanding of how highly sensitive people experience that the personality trait affects various relationships and social situations in today’s social society. Data were collected through semi structured interviews with nine people defining themselves as HSP. The answers from the informants were thereafter analyzed using thematic content analysis to get an overview of their experiences. The result indicates that the personality trait affects the relationships with others in various ways, for example by the ability of the highly sensitive to understand others, their deep processing and their need to avoid overstimulation. It also emerged that the characteristics of the highly sensitive people were not always accepted or understood by the surroundings.

How congruence cues and congruence-based expectations may together shape perception in virtual reality (VR) still need to be unravelled. We linked the concept of plausibility used in VR research with congruence-based modulation by assessing brain responses while participants experienced vehicle riding experiences in VR scenarios. Perceptual plausibility was manipulated by sensory congruence, with multisensory stimulations confirming with common expectations of road scenes being plausible. We hypothesized that plausible scenarios would elicit greater cortical responses. The results showed that: (i) vibrotactile stimulations at expected intensities, given embedded audio-visual information, engaged greater cortical activities in frontal and sensorimotor regions; (ii) weaker plausible stimulations resulted in greater responses in the sensorimotor cortex than stronger but implausible stimulations; (iii) frontal activities under plausible scenarios negatively correlated with plausibility violation costs in the sensorimotor cortex. These results potentially indicate frontal regulation of sensory processing and extend previous evidence of contextual modulation to the tactile sense.

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Thesis (MBA (Business Management))--Stellenbosch University, 2008. / ENGLISH ABSTRACT: The primary objective of this study was to establish if the Adolescent/Adult Sensory Profile questionnaire (AASP) could be used as a recruitment tool in selecting contact centre agents with a higher predictability for success and hence higher productivity. Contact centres around the globe face the challenge of high staff turnover and absenteeism, reducing profitability. It seems that work performance related to the way in which adults process sensory input has not been well researched. A model was developed by Dunn (Brown et al., 2001) based on the intersection of a neurological threshold continuum and a behavioural continuum and yielding four quadrants: Quadrant 1, Low Registration (of stimuli); Quadrant 2, Sensation Seeking; Quadrant 3, Sensory Sensitivity, and Quadrant 4, Sensation Avoiding. Forty-eight contact centre agents employed by Liberty Life were selected and assessed on the AASP. Performance data for each contact centre agent were collected: available time, auxiliary time, log-in time, quality assurance, absenteeism and length of service. Spearman rank correlations were conducted to test if relationships exist between any of the four quadrants and the performance measures. As an additional investigation, a Suitability Score (based on clustering of scores with a percent assigned) was derived for each contact centre agent and also correlated with the above performance measures. Significant relationships were found between Quadrant 2 scores and three of the performance measurement criteria. As the Quadrant 2 scores increase, the average available time of the agents will decrease and their average log-in time will increase. Absenteeism increased as well, which is expected to have a negative effect on the productivity of the contact centre. The Quadrant also had a high predictability for Suitability Ratings indicating that as the Quadrant 2 score increases, the suitability of the contact centre agents increases as well. Regarding Quadrant 3 (sensory sensitivity) scores, quality assessment, total days of absenteeism and average absenteeism relate negatively. It seems that contact centre agents with high sensory sensitivity are less suitable for the job. As the score increases the quality assessment scores decrease, which is not what is required in terms of quality standards. A negative relationship exists between Quadrant 3 scores and the Suitability Rating scores, indicating that the higher the quadrant scores the less suitable the contact centre agents are to work in the contact centre environment. Quadrant 4 (sensation avoiding) has a negative relationship with Suitability Rating scores, which indicates that the higher the quadrant score the less suitable the contact centre agent is to work in the contact centre environment. No significant relationships were recorded between the performance measurements and Quadrant 1 (low registration) and Quadrant 4 (sensation avoiding), even though, logically, one would expect agents with less distraction to be more productive. Further studies are recommended before the Adolescent/Adult Sensory Profile questionnaire is used as a recruitment tool. Future studies could categorise the quadrant scores into clusters and then test for relationships with the set performance measurements. The Suitability Rating was used in a first attempt to match individuals in a specific job according to specific sensory profiles. This measure has not yet been tested for validity and reliability, which must be done prior to further study using it. / AFRIKAANSE OPSOMMING: Die primêre doel van hierdie studie was om vas te stel of die Adolescent/Adult Sensory Profile (AASP) vraelys gebruik kan word as ‘n hulpmiddel vir die werwing en seleksie van kontaksentrum agente, met ‘n hoër waarskynlikheid van sukses en, dus, hoër produktiwiteit. Kontaksentrums op elke vasteland kom te staan voor die probleem van hoë personeelomset en werksafwesigheid wat winsgewendheid verlaag. Die manier waardeur volwasse mense hul sensoriese insette verwerk, in verband met werkprestasie, is nog nie goed ondersoek nie. ‘n Model is deur Dunn (Brown et al., 2001) ontwikkel wat gebasseer is op die kruispunt van ‘n neurologiese drumpel kontinuum en ‘n gedragskontinuum wat tot vier kwadrante lei: Kwadrant 1, Lae Registrasie (van stimuli); Kwadrant 2, Sensasie Soekend; Kwadrant 3, Sensoriese Sensitiwiteit, en Kwadrant 4, Vermyding van Sensasie. Agt-en-veertig kontaksentrum agente wat in diens van Liberty Life is, is geselekteer en beoordeel volgens die AASP. Prestasiedata is saamgestel vir elke kontaksentrum agent: beskikbare tyd, oortollige tyd, teenwoordige tyd, kwaliteitsversekering, werksafwesigheid en jare diensplig. Spearman rang korrelasies is onderneem om te toets of daar verbande bestaan tussen enige van die vier kwadrante en die prestasiemaatstaf. In ‘n addisionele ondersoek is ‘n geskiktheidsmaatstaf ontwikkel wat gebasseer is op trosvorming van tellings met ‘n toegekende persentasie. Dit is gedoen vir elke kontaksentrum agent en hierdie tellings is ook gekorreleer met bogenoemde prestasiemaatstawwe. Statisties-beduidende positiewe verbande is gevind tussen Kwadrant 2 (sensasie soekend) tellings en drie van die prestasiemetingskriteria. As die telling van Kwadrant 2 toeneem, neem die gemiddelde beskikbare tyd af en die teenwoordige tyd van agente toe. Werksafwesigheid het ook toegeneem, wat moontlik negatief kan inwerk op die produktiwiteit van die kontaksentrum. Die kwadrant het ook ‘n hoë waarskynlikheid openbaar in die geval van die Gekiktheidsmaatstaf, wat aandui dat, namate die Kwadrant 2 telling toeneem, die gekiktheid van die kontaksentrum agent ook toeneem. Wat Kwadrant 3 (sensoriese sensitiwiteit) tellings betref, bestaan daar ‘n negatiewe verband tussen kwaliteitsversekering, totale aantal dae van werksafwesigheid en gemiddelde werksafwesigheid. Dit blyk dat kontaksentrum agente met hoë sensoriese sensitiwiteit dalk minder geskik is vir die pos. Soos wat die telling vir sensoriese sensitiwiteit toeneem, neem die telling vir kwaliteitsversekering af, wat nie in terme van kwaliteitstandaarde aanvaarbaar is nie. Daar bestaan ‘n negatiewe verband tussen Kwadrant 4 (sensasie vermyding) tellings en die tellings vir die Geskiktheidsmaatstaf, wat aandui dat hoe hoër die kwadrant telling, hoe minder geskik is die agent. Geen statisties-beduidende verbande is gevind tussen die prestasietellings van Kwadrant 1 (lae registrasie) en Kwadrant 4 (sensasie vermyding) nie. Normaalweg sou mens verwag dat agente met minder afleiding, meer produktief sou wees. Daar word voorgestel dat verdere studies onderneem word voordat die Adolescent/Adult Sensory Profile as ‘n werwingsmaatstaf gebruik word. Toekomstige studies kan die kwadrant tellings saamvoeg in trosse en dan toets vir verbande met die vooropgestelde prestasiemaatstawwe. Die Geskiktheidsmaatstaf is gebruik as ‘n eerste poging om individue saam te voeg in ‘n spesifieke pos, volgens ‘n spesifieke sensoriese profiel. Hierdie maatstaf moet vir toepaslikheid en betroubaarheid in verdere studie getoets word, voordat dit gebruik kan word.

This diploma thesis deals with mutism from the perspective of specialized czech and foreign literature. The character of the thesis is theoretical and the thesis is divided into three parts. In the first chapter, there is mutism described based on the study of czech specialized literature as well as etiology, symptoms, diagnostics and treatment. The second chapter describes the same categories but based on the study of foreign literature. The last part is dedicated to the analysis and comparison of acquired knowledge in particular areas. The most signifiant differences can be found in the area of diagnostics and therapy of mutisms, which are more elaborated in foreign literature than in Czech literature. Some differences appear in all other areas of mutism. The learning theory is the characteristic feature of foreign literature in the field of etiology of mutism, also the social enxiety is the characteric feature in the area of symptoms and treatment; overall we can see a dominant influence of the Diagnostic and Statistical Manual of Mental Disorders. The Czech literature provides a number of different views not only on the definition of mutism, but also on the etiology and symptomatology. The diagnostics and the therapy of mutism is not further elaborated in the Czech literature.

One of the most powerful and important applications that the brain accomplishes is solving the sensory "cocktail party problem:" to adaptively suppress extraneous signals in an environment. Theoretical studies suggest that the solution to the problem involves an adaptive filter, which learns to remove the redundant noise. However, neural learning is also in its infancy and there are still many questions about the stability and application of synaptic learning rules for neural computation. In this thesis, the implementation of an adaptive filter in the brain of a weakly electric fish, A. Leptorhynchus, was studied. It was found to require a cerebellar architecture that could supply independent frequency channels of delayed feedback and multiple burst learning rules that could shape this feedback. This unifies two ideas about the function of the cerebellum that were previously separate: the cerebellum as an adaptive filter and as a generator of precise temporal inputs.

One of the most powerful and important applications that the brain accomplishes is solving the sensory "cocktail party problem:" to adaptively suppress extraneous signals in an environment. Theoretical studies suggest that the solution to the problem involves an adaptive filter, which learns to remove the redundant noise. However, neural learning is also in its infancy and there are still many questions about the stability and application of synaptic learning rules for neural computation. In this thesis, the implementation of an adaptive filter in the brain of a weakly electric fish, A. Leptorhynchus, was studied. It was found to require a cerebellar architecture that could supply independent frequency channels of delayed feedback and multiple burst learning rules that could shape this feedback. This unifies two ideas about the function of the cerebellum that were previously separate: the cerebellum as an adaptive filter and as a generator of precise temporal inputs.