Les informations sensorielles peuvent être atténuées de la périphérie jusqu'au cortex durant le mouvement. Notre hypothèse est que l'information somatosensorielle serait facilitée durant la planification du pas où il serait inopportun de supprimer ces informations cruciales. Nous avons enregistré les potentiels somatosensoriels (SEPs) évoqués par vibration bilatérale des muscles des chevilles afin de stimuler la proprioception.Les résultats montrent que la composante évoquée corticale précoce restait inchangée mais une composante tardive négative était significativement augmentée durant la planification du pas.Pour tester si cette facilitation proprioceptive était due aux contraintes d'équilibre, la même expérience fut effectuée en microgravité où cette facilitation disparut, malgré la restauration d'un cadre de référence spatial.Cette facilitation tardive survint pendant l'imagerie motrice kinesthésique d'un pas planifié, démontrant que l'imagerie mentale intègrerait les contraintes d'équilibre et posturales requises pour la tâche, ceci étant confirmé par la disparition de cette facilitation lors de la planification du pas imaginé en microgravité.Ceci démontre au niveau neurophysiologique, une modulation de la transmission des afférences sensorielles selon leur pertinence pour planifier un mouvement. Cette facilitation résulterait de mécanismes prédictifs reliés à l'importance de contrôler l'équilibre du corps avant l'initiation du pas, car ce processus survint durant la planification d'un pas exécuté ou imaginé. Il serait basé sur un modèle interne de l'action impliquant des lois physiques du mouvement (1-g modèle) car cette facilitation fut supprimée en microgravité. / Sensory inputs can be attenuated from the periphery to the cortex during voluntary movements. Our hypothesis is that the somatosensory information could be facilitated during the planning of a step. It would appear dysfunctional to suppress somatosensory information, which is considered to be of the utmost importance for gait planning. We recorded somatosensory potentials (SEPs) evoked by bilateral ankle vibration to stimulate proprioception. Results showed that cortical early evoked component remained unchanged but a negative late component was significantly increased during step planning. To determine whether this facilitation of proprioceptive inputs was related to gravitational equilibrium constraints, we performed the same experiment in microgravity. In the absence of equilibrium constraints, both components did not significantly differ between the static and stepping conditions, despite the restoration of a body in space reference frame.This late facilitation occurred during kinesthetic motor imagery of a planned step, suggesting that mental imagery would integrate postura and balance constraints required for the task, as it was confirmed byt the lack of this facilitation during the planning of an imagined step in microgravity.These observations provide neurophysiological evidence that the brain exerts a dynamic control over the transmission of the afferent signal according to their current relevance during movement preparation.These processes should be based on internal model of action involving the physical laws of motion (1g-model) as this sensory facilitation was suppressed in microgravity when planning motor imagery.

Submitted by Ana Carolina de Lima Sarmento (carol_sarmento@hotmail.com) on 2018-06-26T16:48:22Z No. of bitstreams: 1 VERSÃO FINAL DISSERTAÇÃO ANA SARMENTO.pdf: 4193853 bytes, checksum: 411f0e8e77081749a480a2df69ae5228 (MD5) / Approved for entry into archive by Lêda Costa (lmrcosta@ufba.br) on 2018-06-26T17:51:53Z (GMT) No. of bitstreams: 1 VERSÃO FINAL DISSERTAÇÃO ANA SARMENTO.pdf: 4193853 bytes, checksum: 411f0e8e77081749a480a2df69ae5228 (MD5) / Made available in DSpace on 2018-06-26T17:51:53Z (GMT). No. of bitstreams: 1 VERSÃO FINAL DISSERTAÇÃO ANA SARMENTO.pdf: 4193853 bytes, checksum: 411f0e8e77081749a480a2df69ae5228 (MD5) / FUNDAÇÃO DE AMPARO A PESQUISA DO ESTADO DA BAHIA - FAPESB / Os interiores revelam não só um espaço físico, mas também um ambiente psicológico de valores, gestos e significados. Partindo da problemática “Como diminuir os impactos ambientais em projetos de interiores?”, no presente trabalho, apresenta-se como objetivo geral proporcionar aos designers de interiores uma metodologia de projeto que permita uma antecipação dos impactos ambientais, partindo-se da análise do modelo IDSRS (Indicadores de Design, Sustentabilidade e Responsabilidade Social), desenvolvido por Souza (2007) no contexto do design de produto, que foi adaptado para uso no design de interiores. Com isso, viabiliza a associação desse percurso projetivo e avaliativo dos impactos, pelos atores envolvidos a uma experiência multissensorial voltada ao sentir, perceber, notar e compreender, que se constituem em elementos-chave para a construção de uma percepção ambiental formativa para o processo de tomada de decisões e para a educação ambiental. Esta pesquisa configura-se de natureza exploratória e qualitativa, pois busca familiarizar-se com o tema, reunindo informações sobre as relações existentes entre sustentabilidade e design de interiores. Integram os procedimentos metodológicos da pesquisa: coleta e análise sistemática de dados, levantamento bibliográfico, visitas em loco, estudo de caso descritivo e consolidação do modelo adaptado por meio da teoria fundamentada em dados. O estudo de caso tomou como base a construção de uma residência localizada em Itacimirim – BA, onde foram acompanhadas todas as etapas da construção, desde a concepção do projeto até a sua implementação/execução. O estudo tem como principal contribuição refletir sobre todas as etapas que envolvem o projeto de interiores, adequando esses ambientes aos parâmetros da sustentabilidade. Pretende-se, a partir da utilização do modelo IDSRS adaptado, contribuir com a antecipação dos impactos ambientais e com um ambiente técnico mais definido, estabelecendo claramente o papel de todos os agentes envolvidos. / The interiors reveal not only a physical space, but also a psychological environment of values, gestures and meanings. Starting from the problematic: How to reduce the environmental impacts in interior projects? The objective of this work is to provide interior designers with a design methodology that allows an anticipation of environmental impacts through a model of sustainability indicators. The IDSRS model (Indicators of Design, Sustainability and Social Responsibility), developed by Souza (2007) in the context of product design, was adapted for use in interior design. As specific objectives, we identified the bibliography referring to the practice of sustainability with a cut-out for interior design, described the IDSRS model, adapted to interior design and demonstrated its use in a case study. With this, it makes possible the association of this projective and evaluative course of the impacts, by the involved actors to a multisensorial experience focused on the perception, perceiving, noting and understanding, that are constituted in key elements for the construction of a formative environmental perception for the process of decision-making and environmental education. This research is of an exploratory and qualitative nature, as it seeks to familiarize itself with the theme, gathering information on the relationship between sustainability and interior design. They integrate the methodological procedures of the research: analysis and systematic analysis of data, bibliographic survey, site visits, descriptive case study and a consolidation of the model adapted through the theory based on data. The case study was based on the construction of a residence located in Itacimirim - BA where we follow all stages of construction, from project design to implementation / execution. The main contribution of the study is to reflect on all the steps involved in interior design, adapting these environments to the parameters of sustainability. It intends from its use to contribute with the anticipation of the environmental impacts and with a more defined technical environment, clearly establishing the role of all the agents involved.

L'espace entourant notre corps est d'une importance vitale: nous surveillons attentivement les objets (animés et inanimés) qui entrent dans les limites de l'espace à immédiate proximité du corps pour interagir avec eux. Dans le domaine des neurosciences cognitives, cet espace est exemplifié par le concept d'espace péripersonnel (PPS), une représentation hautement plastique qui intègre des stimuli tactiles et visuels présentés sur et près du corps. Cette représentation semble contribuer au guidage efficace des actions, cependant dans la littérature on ne retrouve aucune preuve substantielle de l'implication du PPS dans le contrôle des actions. Un argument en faveurs de cette hypothèse dériverait de la preuve que la plasticité du PPS peut effectivement survenir avant le début du mouvement, plutôt que pendant le mouvement. Les résultats de la première étude (chapitre II) révèlent que les informations visuelles et tactiles interagissent de manière significative déjà au cours de la phase de planification de l'action et que cette interaction visuo-tactile augmente ultérieurement au cours des étapes successives du mouvement. Un tel processus de « remappage » visuo-tactile du PPS, qui précède temporellement et accompagne par la suite l'exécution de l'action motrice, semble donc idéalement adapté à pour aider au guidage de nos actions. Récemment, il a été suggéré que le PPS pourrait jouer un rôle dans le guidage des interactions motrices entre individus. En psychologie sociale, l'espace autour du corps est appelé espace interpersonnel (IPS), défini comme l'espace que les individus maintiennent autour d'eux et dans lequel les autres ne peuvent pas pénétrer sans susciter d'inconfort. En raison de certaines similitudes entre les représentions du PPS et du IPS, certains auteurs ont soulevé la question d'un éventuel partage de certaines caractéristiques fonctionnelles entre ces deux représentations. Le deuxième objectif de ma thèse etait de tester cette hypothèse en exploitant un autre processus de «remappage» plastique du PPS, c'est-à-dire celui induit par l'utilisation d'un outil. Les résultats de la deuxième étude (chapitre IV) montrent que l'utilisation «standard» d'un outil «allonge» le PPS, mesuré par la distance d'atteignabilité d'une autre personne, mais n'influence pas l'IPS, mesuré par la distance de confort envers la même personne. Dans la troisième étude (chapitre V), nous avons introduit une nouvelle variante plus sociale de l'utilisation d'un outil pour examiner la plasticité sensorimotrice et sociale des deux espaces. Les résultats obtenus révèlent que l'utilisation sociale d'un outil «allonge» le PPS et en même temps «réduit» l'IPS. La démonstration que l'on peut induire des changements directionnellement opposés entre les deux représentations, falsifie l'hypothèse selon laquelle il peut y avoir un chevauchement fonctionnel entre PPS et IPS. Ces exemples de dissociation fonctionnelle peuvent donc servir à éviter une association inappropriée entre les deux concepts. Si l'hypothèse de l'identité fonctionnelle avec l'IPS ne semble pas légitime, il n'en demeure pas moins que le PPS est également sensible aux variables sociales. La dernière étude (Chapitre VII) vise donc à explorer cette sensibilité du PPS vers une dimension sociale fondamentale, encore inexplorée: la propriété privée. Les résultats de la quatrième étude indiquent que la propriété d'un objet, qu'elle soit considérée comme individuelle ou partagée, est essentielle pour l'émergence des propriétés dynamiques du PPS. Les stimuli visuels influencent effectivement la perception tactile d'une manière plus marquée au début du mouvement, mais seulement lorsque l'objet appartient au participant. Il convient de noter qu'un effet similaire apparaît également lorsque l'on observe une autre personne agir sur l'objet qui lui appartient... [etc] / The zone that surrounds our body is of vital importance: we carefully monitor the objects (both animate and inanimate) that enter the boundaries of the immediate space around the body to interact with them. In the neurocognitive field such a space is captured by the concept of peripersonal space (PPS), a highly plastic representation that integrates tactile and visual stimuli presented on, and close to, the body. This system seems to contribute to the efficient guidance of actions, yet, a clear demonstration of a prominent role of PPS in control of actions is critically lacking. Strong support for this would derive from evidence that PPS plastic changes occur before rather than after movement onset. The results from the first study (Chapter II) reveal that visual and tactile information strongly interact already during the planning phase of action and this visuo-tactile interaction is further enhanced during subsequent movement phases. Such a visuo tactile remapping of PPS that temporally precedes and subsequently accompanies overt motor execution is ideally suited to planning and guiding actions. Recently, it has been suggested a possible involvement of PPS in the guidance of motor interactions between individuals. In social psychology, the space around the body is termed interpersonal space (IPS), defined as the area individuals maintain around themselves into which others cannot intrude without arousing discomfort. Because of some similarities between the PPS and IPS constructs, some authors have raised the question of whether they share some functional features. The second aim of my thesis is to test this hypothesis by taking advantage of another PPS remapping, namely that one induces by tool-use. The results of the second study (Chapter IV) show that “standard” tool-use ‘extends’ PPS, as measured by reaching distance toward a peer, but does not affect IPS, as measured by the comfort distance toward the same peer. In the third investigation (Chapter V), we introduced a novel form of “social” tool-use setting to test for both sensorimotor and social plasticity of the two spaces. The findings that social tool–use ‘extends’ PPS and ‘reduces’ IPS, inducing opposite changes on each representation, clearly disconfirms the hypothesis . that there might be functional overlap between these sectors of space. Such examples of functional dissociation may therefore be sufficient to warn scholars to refrain from risky conflations between the two concepts. If the assumption of functional identity with IPS does not appear to be legitimate, it is true that PPS is sensitive to social features. The last study (Chapter VII) is thus aimed at probing this sensitivity of PPS to a so far unexplored but fundamental social dimension: ownership. The results from the forth study indicate that, whether considered to be as individual or shared property, ownership of an object is critical for the PPS dynamic properties to emerge. Visual stimuli affected touch perception more strongly at the movement onset than before, but only when the object belonged to the acting participant. Interestingly, a similar remapping was found when simply observing the peer acting on her own belonging. In a follow-up experiment we investigated PPS plastic changes when property of the target object was shared between the two agents. In this case, PPS remapping emerged not only when acting in first person, but also when observing the peer acting upon the shared object. Taken together, these findings critically inform current theoretical models about space around our body and about its function in our sensorimotor and social inter-actions

In the last decade, neuroscience and psychology alike have paid increasing attention to the study of affective touch, which refers to the emotional and motivational facets of tactile sensation. Some aspects of affective touch have been linked to a neurophysiologically specialised system, namely the C tactile (CT) system. While the role of this system for affiliation, social bonding and communication of emotions have been investigated, less is known about the potential role of affective touch in the awareness of the body as our own, i.e. as belonging to our psychological 'self'. This thesis attempted to contribute to the knowledge on affective touch and its relation to body awareness, by exploring the potential role of this modality to the way we perceive and make sense of our body as our own. Specifically, this work aimed to advance the current state of knowledge by investigating: 1) the effect of affective touch on the sense of body ownership, which is a fundamental aspect of body awareness; 2) the relation between interoceptive modalities, originating both internally (i.e. cardiac awareness) and peripherally (i.e. affective touch), and exteroception in body awareness; 3) the effect of intranasal oxytocin on the perception of affective touch and bodily awareness; 4) the perception and social modulation of affective touch in psychiatric patients who show difficulties in body awareness, namely patients with Anorexia Nervosa, and 5) the modulating role of self-other distinction and of self-other relation in the perception of affective touch and body awareness. In a first experiment (N = 52) the rubber hand illusion paradigm was used to investigate the role played by CT-optimal, affective touch in the sense of body ownership. The results showed that slow, pleasant touch enhanced the experience of embodiment in comparison to faster, neutral touch, suggesting that affective touch might uniquely contribute to the sense of body ownership. The following study (N = 75), used a similar methodology to test whether interoceptive sensitivity as measured by a heartbeat counting task would modulate the extent to which affective touch influences the multisensory process taking place during the rubber hand illusion. The results could not confirm a systematic relation between interoceptive sensitivity and the perception of affective touch, nor its influence on body ownership. The next study (N = 41) included a double-blind, placebo-controlled, randomised, cross-over design testing the effect of intranasal oxytocin on the perception of affective touch and body ownership, as measured by means of the rubber hand illusion. There was no evidence supporting the hypothesis that intranasal oxytocin could influence the CT system as tested in this study. The next study (N = 55) applied some of the above methodologies to investigate the perception of CT-optimal touch in patients with anorexia nervosa and its emotional modulation by top-down factors. The results confirmed the hypothesis that people with anorexia nervosa show a reduced perception of affective touch compared to healthy controls, but its perception was not influenced by top-down affective modulation, in the sense that both patients and healthy controls perceived touch as more pleasant when presented concurrently with positive facial expressions compared to neutral and negative faces. Finally, the last two studies (N = 76 and 35 healthy volunteers, respectively) focused on the relationship between affective touch and body awareness in the context of social cognition. These studies used both online and offline social modulation paradigms to investigate the role of self-other distinction and of self-other relation in the perception of affective touch. The results showed that positive top-down social information can enhance the perceived pleasure of tactile stimulation. Taken together, these studies point to the central role of affective touch in body awareness and social cognition. Finally, they also pave the way for future studies examining the role of disruptions of the CT system in the development of neuropsychiatric impairments of body awareness and social cognition.

La construction de la représentation de soi est basée sur l'intégration des informations que l'on reçoit des différentes modalités sensorielles telles que les informations visuelles, auditives, tactiles ou proprioceptives. L'interaction entre les actions et les mouvements, et plus récemment les interactions sociales et l'espace ont été étudiées essentiellement au niveau comportemental, moins au niveau fonctionnel et beaucoup reste encore à élucider. En particulier, il est important et essentiel de comprendre exactement quels processus sont impliqués dans la construction d'une représentation spatiale et comment ces processus sont mis en oeuvre, non seulement au niveau local par l'activité de neurones spécifiques, dans une zone corticale spécifique, mais aussi à l'échelle du réseau dans son ensemble ainsi qu'à l'échelle du cerveau entier. Le premier axe de ma thèse s'intéresse à l'espace peripersonnel, qui est l'espace le plus proche de nous et qui représente l'un des sous-espaces fonctionnels de la représentation spatiale. Nous faisons l'hypothèse que ce sont les mêmes régions qui contribuent à la convergence multisensorielle, à la prédiction des conséquences sur le traitement tactile d'une stimulation visuelle approchant le corps et à la construction de l'espace peripersonnel. Pour tester cette hypothèse, nous avons étudié l'effet des aspects prédictifs temporels et spatiaux d'un stimulus visuel dynamique sur la détection du stimulus tactile chez l'Homme (étude comportementale) et le primate non humain (étude en IRM fonctionnelle) ainsi que les bases neuronales de la représentation de l'espace proche et de la représentation de l'espace lointain, chez le primate non humain (étude en IRM fonctionnelle). Nous mettons en évidence l'implication d'un réseau parieto-frontal, essentiellement composé par l'aire intrapariétale ventrale VIP et l'aire prémotrice F4 qui sont activées par ces trois mécanismes différents. Nous proposons que ce réseau traite non seulement la trajectoire de l'objet approchant vis-à-vis du corps, mais qu'il anticipe également ses conséquences sur le corps et prépare des actions de protection en réponse à ce stimulus approchant. Le deuxième axe de ma thèse porte sur la caractérisation de l'étendue de la plasticité dans la représentation visuelle dans le cerveau adulte (par opposition aux premiers stades de plasticité observées autour des périodes critiques du développement) et en particulier, sur des développements méthodologiques permettant de mesurer les changements fins dans le cortex visuel induits par une telle plasticité. Plus précisément, nous avons développé un ensemble de méthodes d'IRM à haute résolution : imagerie fonctionnelle (cartographie visuelle à haute résolution, IRM au repos), pharmacologique (imagerie spectroscopique du GABA) et structurelle (IRM anatomique, DTI basée sur la diffusion des molécules d'eau), afin de définir des mesures de référence pour évaluer les changements induits par la plasticité à différents moments après son induction, à travers une étude longitudinale réalisée chez les mêmes animaux. Certaines de ces méthodes nécessitent encore quelques raffinements et ajustements mais, dans l'ensemble, elles montrent leur potentiel prometteur pour étudier la plasticité chez les primates non humains. Dans l'ensemble, ce travail de thèse a permis de créer un lien fonctionnel entre les études d'IRMf effectuées chez l'Homme et les études d'enregistrement d'électrophysiologies chez le primate non humain. De plus, il entraine de nouvelles stratégies et pistes d'explorations à étudier dans le domaine de la représentation spatiale, à la fois chez l'Homme et le primate non humain / The construction of the representation of self is based on the integration of information received by our different sensory modalities such as visual, auditory, tactile or proprioceptive information. The interaction between actions and movements and more recently social interactions and space are being explored at the behavioral level, but less so at the functional level and much more remains to be elucidated. In particular, it is important and fundamental to understand exactly which processes are involved in space representation and how, not only from a partial view focusing on specific cortical areas and single neuron processes but at the scale of the whole brain and the functional networks. The first axis of my thesis focuses on peripersonal space, that is the space that is closest to us, and represents one of the functional subspaces of spatial representation. We assume that it is the same regions that contribute to multisensory convergence, to the prediction of the consequences of a looming visual stimulus onto tactile processing and to the construction of peripersonal space. To test this hypothesis, we investigated the effect of the temporal and spatial predictive aspects of a dynamical looming visual stimulus onto tactile stimulus detection in humans (behavioral study) and non-human primates (fMRI study); the neural bases of near space and far space representations, in non-human primate (fMRI study). We highlight the involvement of a parieto-frontal network, essentially composed by the ventral intraparietal area VIP, the premotor area F4 as well as striate and extra-striate cortical regions, which are activated by these three different mechanisms. We propose that this network not only processes the trajectory of the looming object with respect to the body, but also anticipates its consequences onto the body and prepares protective actions in response to the looming stimulus. The second axis of my thesis focuses on characterizing the extent of plasticity in the visual representation of the adult brain (as opposed to the early stages around the critical developmental periods) and in particular, how the associated fine-grained changes in the visual cortex can be precisely quantified along multiple dimensions (anatomical, functional, pharmacological). Specifically, we have developed a set of high-resolution MRI methods to assess functional (high-resolution visual mapping fMRI, rs-MRI), pharmacological (GABA spectroscopy imaging) and structural (anatomical MRI, DTI) imaging to define reference measures against which to evaluate the changes induced by plasticity at different times after its induction, through a longitudinal study performed in the same animals. Some of these methods need to be more refined but they show that they are really promising to study plasticity in nonhuman primate. On the whole, this present doctoral research allows to make a functional link between human fMRI studies and monkey single cell recording studies and provides new strategies and explorations to perform on the spatial representation field both in humans and non-human primates

Cette thèse s'est intéressée aux relations entre les mouvements biologiques et la perception sonore en considérant le cas spécifique des mouvements graphiques et des sons de frottement qu'ils génèrent. L'originalité de ces travaux réside dans l'utilisation d'un modèle de synthèse sonore basé sur un principe perceptif issu de l'approche écologique de la perception et contrôlé par des modèles de gestes. Des stimuli sonores dont le timbre n'est modulé que par des variations de vitesse produites par un geste ont ainsi pu être générés permettant de se focaliser sur l'influence perceptive de cet invariant transformationel. Une première étude a ainsi montré que l'on reconnait la cinématique des mouvements biologiques (la loi en puissance 1/3), et que l'on peut discriminer des formes géométriques simples juste à partir des sons de frottement produits. Une seconde étude a montré l'existence de prototypes dynamiques sonores caractérisant les trajectoires elliptiques, mettant ainsi en évidence que les prototypes géométriques peuvent émerger d'un couplage sensorimoteur. Enfin, une dernière étude a montré qu'une cinématique évoquée par un sonore influence significativement la cinématique et la géométrie d'un geste dans une tâche de reproduction graphique du mouvement d'un point lumineux. Ce résultat révèle l'importance de la modalité auditive dans l'intégration multisensorielle des mouvements continus dans une situation jamais explorée. Ces résultats ont permis le contrôle de modèles de synthèse par des descriptions gestuelles et la création d'outils de sonification pour l'apprentissage de gestes et la réhabilitation d'une pathologie motrice, la dysgraphie. / This thesis focused on the relations between biological movements and auditory perception in considering the specific case of graphical movements and the friction sounds they produced. The originality of this work lies in the use of sound synthesis processes that are based on a perceptual paradigm and that can be controlled by gesture models. The present synthesis model made it possible to generate acoustic stimuli which timbre was directly modulated by the velocity variations induced by a graphic gesture in order to exclusively focus on the perceptual influence of this transformational invariant. A first study showed that we can recognize the biological motion kinematics (the 1/3 power law) and discriminate simple geometric shapes simply by listening to the timbre variations of friction sounds that solely evoke velocity variations. A second study revealed the existence of dynamic prototypes characterized by sounds corresponding to the most representative elliptic trajectory, thus revealing that prototypical shapes may emerged from sensorimotor coupling. A final study showed that the kinematics evoked by friction sounds may significantly affect the dynamic and geometric dimension in the visuo-motor coupling. This shed critical light on the relevance of auditory perception in the multisensory integration of continuous motion in a situation never explored. All of these theoretical results enabled the gestural control of sound synthesis models from a gestural description and the creation of sonification tools for gesture learning and rehabilitation of a graphomotor disease, dysgraphia.

Des études suggèrent que certaines capacités sensorielles peuvent être augmentées chez l’humain, soit i) à la suite d’un entraînement ou ii) à la suite de privation sensorielle précoce. Des études suggèrent qu’une telle altération sensorielle peut être retrouvée chez les personnes ayant subi un entraînement musical. L’interaction entre ce qui est entendu et ressenti est spécialement importante lorsqu’un individu joue d’un instrument de musique. L’entraînement musical est reconnu comme étant une forme d’entraînement multisensoriel incluant des interactions entre des composantes auditives, visuelles et tactiles. Celui-ci peut mener à des réorganisations anatomiques et structurelles dans les régions corticales associées à ces modalités sensorielles. Plusieurs études comportementales ont révélé des habiletés de détection tactile améliorées chez les musiciens. Il est toujours incertain que ces améliorations puissent être retrouvées lors de processus plus complexes tels que la reconnaissance des émotions. Une autre population d’étude pourrait aussi révéler une altération des capacités tactiles, soit les personnes sourdes de naissance. Des études en imagerie ont révélé que les stimuli vibrotactiles activaient les régions auditives chez les personnes sourdes, suggérant ainsi une importante réorganisation tactile chez ces individus. Pourtant, au niveau comportemental, les capacités de détection tactile semblent similaires aux contrôles. Récemment, il a été suggéré que des processus tactiles plus complexes pourraient permettre de révéler des différences comportementales entre les personnes sourdes et entendantes. Malheureusement, tout comme chez les musiciens, ces processus n’ont toujours pas été évalués à ce jour. L’objectif principal de cette thèse est donc d’évaluer i) la perception unisensorielle tactile, auditive ainsi que multisensorielle chez les musiciens et ii) la perception unisensorielle tactile chez les sourds à l’aide de tâches non-musicales et musicales. Chez les musiciens, les résultats de cette thèse suggèrent des capacités de discrimination fréquentielle auditive, tactile et audiotactile améliorées (étude 1) ainsi que des améliorations de la perception d’émotions musicales complexes auditive et tactile (étude 2). Ces études supportent l’hypothèse qu’une formation musicale à long terme : i) entraîne une amélioration des capacités unisensorielles auditives et tactiles, mais surtout que celle-ci s’étend à des processus tactiles complexes, ii) a un impact à tous les niveaux hiérarchiques du traitement sensoriel et cognitif. Chez les individus sourds, les résultats ont révélé un plus haut taux d’erreurs lors de la tâche de détection d’ordre temporel tactile (étude 3). Ce résultat suggère que la cartographie spatiale du toucher est altérée chez les individus sourds. De plus, l’étude ayant mesuré la perception des émotions tactiles a révélé que ceux-ci sont capables d’identifier des émotions via la modalité tactile seule et ont même une capacité améliorée à identifier la joie (étude 4). Cette capacité accrue à percevoir la joie dans une mélodie via la modalité tactile illustre que des habiletés tactiles complexes peuvent être améliorées suite à une privation auditive de longue date. Ces deux études mises en commun illustrent que des capacités tactiles complexes non-musicales et musicales sont altérées chez l’individu sourd, ce qui supporte les études suggérant une réorganisation corticale des aires auditives et tactiles chez les individus sourds. / Studies suggest that some sensory abilities may be increased in humans, either i) following training or ii) following early sensory deprivation. Studies suggest that such sensory alteration can be found in people who have undergone musical training. The interaction between what is heard and felt is especially important when an individual is playing a musical instrument. Musical training is well-known as a form of multisensory training that includes interactions between auditory, visual and tactile modalities. This can lead to anatomical and structural reorganizations in the cortical regions associated with these sensory systems. Several behavioral studies have revealed improved tactile perception skills in musicians. It is still unclear whether these improvements can be found for more complex processes, such as recognition of emotions. Similar alteration of tactile abilities may also be found in another population, namely early-deaf individuals. Imaging studies have shown that vibrotactile stimuli activate auditory regions following deafness, suggesting a significant tactile reorganization of their cortex. Yet, from a behavioral point of view, tactile perception in deaf seems similar to controls. Recently, it has been suggested that more complex tactile processes may reveal behavioral differences between deaf and normal-hearing individuals. Unfortunately, similarly to musicians, these processes have not been investigated to date. The main objective of this thesis is therefore to evaluate via non-musical and musical tasks i) tactile, auditory and multisensory perception of music among musicians and ii) tactile perception of music among deaf individuals. For musicians, results of this thesis suggest enhanced auditory, tactile and audio-tactile frequency discrimination capabilities (Study 1). Also, results suggest an increase perception of emotions in music, which suggests improvements for complex auditory and tactile abilities (Study 2). These studies support the hypothesis that long-term musical training: i) leads to improved auditory and tactile perception, but especially that it extends to complex tactile processes, ii) has an impact at all hierarchical levels of sensory and cognitive processing For deaf individuals, results revealed a higher error rate during the tactile temporal order detection task (Study 3). This result suggests that spatial mapping of touch is impaired in deaf individuals. In addition, the study measuring tactile perception of emotion in music revealed that they are able to identify emotions via tactile modality solely. Also, improvements were found for the identification of happy emotion via tactile modality solely (Study 4). This increased ability to perceive happiness in a melody via the tactile modality illustrates that complex tactile skills can be improved following longstanding hearing deprivation. These two studies together suggest that complex non-musical and musical tactile abilities are altered in the deaf individual, which supports studies suggesting a cortical reorganization of auditory and tactile areas following long-term auditory deprivation.

Within dementia care, there is a need to facilitate appropriate sensory experiences and opportunities for meaningful engagement for people living with dementia, particularly in later stages. As such, the provision of multisensory environments designed to meet the needs of these individuals and offering suitable occupation and stimulation, have increasingly gained significance. In this context, this paper explores the meaning of experience-focused, sensory design and the importance of appropriate sensory stimulation for wellbeing. It refers to recent interdisciplinary research in this area and a new guide advising on design of sensory enhanced spaces in residential dementia care. The primary focus of the paper is a case study showcasing the implementation of sensory design, based on these guidelines. The case study reports on the co-creation of a sensory, experience-focused space for residents with dementia in a London care-home. Based on this example, the paper highlights the value and impact of appropriate sensory design on the wellbeing of people with dementia and their carers. The conclusion discusses the learning and knowledge gained from this process as well as perspectives on further research activities including the analysis of user feedback and evaluation of the design intervention.

We can affirm to apprehend a system in its totality only when we know how it behaves under its natural operating conditions. However, in the face of the complexity of the world, science can only evolve by simplifications, which paradoxically hide a good deal of the very mechanisms we are interested in. On the other hand, scientific enterprise is very tightly related to the advances in technology and the latter inevitably influences the manner in which the scientific experiments are conducted. Due to this factor, experimental conditions which would have been impossible to bring into laboratory not more than 20 years ago, are today within our reach. This thesis investigates neuronal integrative processes by using a variety of theoretical and experimental techniques wherein the approximation of ecologically relevant conditions within the laboratory is the common denominator. The working hypothesis of this thesis is that neurons and neuronal systems, in the sensory and higher cortices, are specifically adapted, as a result of evolutionary processes, to the sensory signals most likely to be received under ecologically relevant conditions. In order to conduct the present study along this line, we first recorded movies with the help of two microcameras carried by cats exploring a natural environment. This resulted in a database of binocular natural movies that was used in our theoretical and experimental studies. In a theoretical study, we aimed to understand the principles of binocular disparity encoding in terms of spatio-temporal statistical properties of natural movies in conjunction with simple mathematical expressions governing the activity levels of simulated neurons. In an unsupervised learning scheme, we used the binocular movies as input to a neuronal network and obtained receptive fields that represent these movies optimally with respect to the temporal stability criterion. Many distinctive aspects of the binocular coding in complex cells, such as the phase and position encoding of disparity and the existence of unbalanced ocular contributions, were seen to emerge as the result of this optimization process. Therefore we conclude that the encoding of binocular disparity by complex cells can be understood in terms of an optimization process that regulates activities of neurons receiving ecologically relevant information. Next we aimed to physiologically characterize the responses of the visual cortex to ecologically relevant stimuli in its full complexity and compare these to the responses evoked by artificial, conventional laboratory stimuli. To achieve this, a state-of-the-art recording method, voltage-sensitive dye imaging was used. This method captures the spatio-temporal activity patterns within the millisecond range across large cortical portions spanning over many pinwheels and orientation columns. It is therefore very well suited to provide a faithful picture of the cortical state in its full complexity. Drifting bar stimuli evoked two major sets of components, one coding for the position and the other for the orientation of the grating. Responses to natural stimuli involved more complex dynamics, which were locked to the motion present in the natural movies. In response to drifting gratings, the cortical state was initially dominated by a strong excitatory wave. This initial spatially widespread hyper-excitatory state had a detrimental effect on feature selectivity. In contrast, natural movies only rarely induced such high activity levels and the onset of inhibition cut short a further increase in activation level. An increase of 30% of the movie contrast was estimated to be necessary in order to produce activity levels comparable to gratings. These results show that the operating regime within which the natural movies are processed differs remarkably. Moreover, it remains to be established to what extent the cortical state under artificial conditions represents a valid state to make inferences concerning operationally more relevant input. The primary visual cortex contains a dense web of neuronal connections linking distant neurons. However the flow of information within this local network is to a large extent unknown under natural stimulation conditions. To functionally characterize these long-range intra-areal interactions, we presented natural movies also locally through either one or two apertures and analyzed the effects of the distant visual stimulation on the local activity levels. The distant patch had a net facilitatory effect on the local activity levels. Furthermore, the degree of the facilitation was dependent on the congruency between the two simultaneously presented movie patches. Taken together, our results indicate that the ecologically relevant stimuli are processed within a distinct operating regime characterized by moderate levels of excitation and/or high levels of inhibition, where facilitatory cooperative interactions form the basis of integrative processes. To gather better insights into the motion locking phenomenon and test the generalizability of the local cooperative processes toward larger scale interactions, we resorted to the unequalized temporal resolution of EEG and conducted a multimodal study. Inspired from the temporal properties of our natural movies, we designed a dynamic multimodal stimulus that was either congruent or incongruent across visual and auditory modalities. In the visual areas, the dynamic stimulation unfolded neuronal oscillations with frequencies well above the frequency spectrum content of the stimuli and the strength of these oscillations was coupled to the stimuli's motion profile. Furthermore, the coupling was found to be stronger in the case where the auditory and visual streams were congruent. These results show that the motion locking, which was so far observed in cats, is a phenomenon that also exists in humans. Moreover, the presence of long-range multimodal interactions indicates that, in addition to local intra-areal mechanisms ensuring the integration of local information, the central nervous system embodies an architecture that enables also the integration of information on much larger scales spread across different modalities. Any characterization of integrative phenomena at the neuronal level needs to be supplemented by its effects at the behavioral level. We therefore tested whether we could find any evidence of integration of different sources of information at the behavioral level using natural stimuli. To this end, we presented to human subjects images of natural scenes and evaluated the effect of simultaneously played localized natural sounds on their eye movements. The behavior during multimodal conditions was well approximated by a linear combination of the behavior under unimodal conditions. This is a strong indication that both streams of information are integrated in a joint multimodal saliency map before the final motor command is produced. The results presented here validate the possibility and the utility of using natural stimuli in experimental settings. It is clear that the ecological relevance of the experimental conditions are crucial in order to elucidate complex neuronal mechanisms resulting from evolutionary processes. In the future, having better insights on the nervous system can only be possible when the complexity of our experiments will match to the complexity of the mechanisms we are interested in.

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