This study will look into to the concepts of Peripersonal Space, The Body Schema and The Body Image. It examines how the terms are typically used and describes the various views about the concepts found in the literature, as well as the contradictions between these views. In the section “The Difficulty to Differentiate the Concepts” the reader gets a deeper understanding of which criteria researchers use to differentiate the concepts from one another. The fact that there are changes in kineamethic model and sensation in humans when they are using a rake is proposed as support for the idea that also the body schema is involved in tool use. In differentiating the Body schema – Body Image from each other (and other types of body representation) we come to the conclusion that positive definitions about different representations is needed and that researchers should unite their views what the definitions should be. We also mention a problem based on the possibility on infinite body representations and a solution by a Bayesian model is proposed that looks at the input as well as the output in experiments.

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Dans le cadre de ce travail de thèse, nous nous sommes intéressés aux relations étroites qu'entretiennent processus moteurs et sensoriels pour déterminer les régions de l'espace où une action directe est possible. Dans ce but, nous nous sommes centrés sur la perception de l' "atteignabilité" d'un objet, c'est-à-dire sur les processus cérébraux qui vont permettre de décider si cet objet pourrait être atteignable ou pas par un mouvement du bras. Pour cela, nous faisons l'hypothèse que ces jugements requièrent la prise en compte de connaissances motrices et corporelles fonctionnelles en plus des informations visuelles extraites de l'environnement. Plus particulièrement, nous proposons qu'ils reposent sur une prédiction des conséquences des actes moteurs potentiels suggérés par cet objet et donc de leur faisabilité à un instant donné. Les études réalisées au cours de cette thèse ont ainsi permis d'écarter l'hypothèse de l'influence de l'effort associé à des actions sur la perception de l'espace atteignable. En revanche, le rôle critique de la prédiction des conséquences sensorimotrices des actions a été mis en évidence, grâce à la démonstration d'une relation forte entre d'une part les correspondances entre la distance visuelle et l'amplitude des mouvements, et d'autre part la distance à laquelle la limite d'atteignabilité est perçue. Les processus d'anticipation sensorimotrice ont également été mis en évidence lors de jugements de perception spatiale en présence de cibles dynamiques, rendant compte du caractère spatio-temporel des mécanismes impliqués. Enfin, une dernière étude a montré l'influence des représentations corporelles et de leur plasticité dans la perception de l'espace péripersonnel, mettant ainsi en lumière l'implication du corps en action dans les jugements perceptifs / In this thesis, we assessed the tight relations between motor and sensory processes used to determine the areas of space in which a direct action is possible. We thus focused on the eprception of the reachability of an object, i.e. on the cerebral processes which allow to decide if an object could be reached or not by moving the arm. To do so, we made the hypothesis that theses judgments require to take into account functional motor and body knowledge, in addition to the visual information extracted from the environment. More specifically, we proposed that these judgments rely on a prediction of the consequences of a potential motor act toward the object, thus on the feasibility of the action at a given moment. Our studies discarded the hypothesis of the role of the effort associated to actions on the perception of reachable space. However, the critical role of predicting the sensorimotor consequences of an action has been showed, by demonstrating the strong relation between on the one hand the correspondence between visual distance and movement amplitude, and on the other hand the distance at which the reachability limit is perceived. Sensorimotor anticipation processes have also been showed in spatial perception involving dynamical targets, showing the spatio-temporal aspect of the involved mechanisms. Finally, our last study showed the influence of body representations and of their plasticity on the perception of peripersonal space, highlighting the implication of the body in action in perceptual judgments

Humans are social beings whose interaction with others constitutes an important part of our well-being. In these social interactions there are certain factors that are essential for us to feel comfortable. One of these factors is to keep a proper “breathing space”. A physical distance to whom we interact, to not have our personal space violated. This space we keep to others is called interpersonal distance (IPD) and might be altered depending on the situation. In the recent decade the neural correlates of IPD have been investigated. The current systematic review aimed to investigate the existing literature on the neural correlations of IPD and how it relates to IPD-behaviour. A systematic search was made in the electric databases Scopus and PubMed. Nine articles remained to be reviewed after screening and selection was done.The results showed the superior parietal cortex, the medial prefrontal cortex, motor areas, occipital areas, and the amygdala to be the most prominent structural brain areas to be involved in IPD. Some functional connections between mentioned brain areas were found but needs to be replicated for better knowledge. The review provides insight into the neural nature of IPD and its behavioural basis.

Developing behaviours for interaction with objects close to the body is a primary goal for any organism to survive in the world. Being able to develop such behaviours will be an essential feature in autonomous humanoid robots in order to improve their integration into human environments. Adaptable spatial abilities will make robots safer and improve their social skills, human-robot and robot-robot collaboration abilities. This work investigated how a humanoid robot can explore and create action-based representations of its peripersonal space, the region immediately surrounding the body where reaching is possible without location displacement. It presents three empirical studies based on peripersonal space findings from psychology, neuroscience and robotics. The experiments used a visual perception system based on active-vision and biologically inspired neural networks. The first study investigated the contribution of binocular vision in a reaching task. Results indicated the signal from vergence is a useful embodied depth estimation cue in the peripersonal space in humanoid robots. The second study explored the influence of morphology and postural experience on confidence levels in reaching assessment. Results showed that a decrease of confidence when assessing targets located farther from the body, possibly in accordance to errors in depth estimation from vergence for longer distances. Additionally, it was found that a proprioceptive arm-length signal extends the robot’s peripersonal space. The last experiment modelled development of the reaching skill by implementing motor synergies that progressively unlock degrees of freedom in the arm. The model was advantageous when compared to one that included no developmental stages. The contribution to knowledge of this work is extending the research on biologically-inspired methods for building robots, presenting new ways to further investigate the robotic properties involved in the dynamical adaptation to body and sensing characteristics, vision-based action, morphology and confidence levels in reaching assessment.

Our ability to interact with the environment requires the integration of multisensory information for the construction of spatial representations. The peripersonal space (i.e., the sector of space closely surrounding one's body) and the integrative processes between visual and tactile inputs originating from this sector of space have been at the center of recent years investigations. Neurophysiological studies provided evidence for the presence in the monkey brain of bimodal neurons, which are activated by tactile as well as visual information delivered near to a specific body part (e.g., the hand). Neuropsychological studies on right brain-damaged patients who present extinction and functional neuroimaging findings suggest the presence of similar bimodal systems in the human brain. Studies on the effects of tool-use on visual-tactile interaction revealed similar dynamic properties of the peripersonal space in monkeys and humans. The functional role of the multisensory coding of peripersonal space is, in our hypothesis, that of providing the brain with a sensori-motor interface for body-objects interactions. Thus, not only it could be involved in driving involuntary defensive movements in response to objects approaching the body, but could be also dynamically maintained and updated as a function of manual voluntary actions performed towards objects in the reaching space. We tested the hypothesis of an involvement of peripersonal space in executing both voluntary and defensive actions. To these aims, we joined a well known cross-modal congruency effect between visual and tactile information to a kinematic approach to demonstrate that voluntary grasping actions induce an on-line re-weighting of multisensory interactions in the peripersonal space. We additionally show that this modulation is handcentred. We also used a motor evoked potentials approach to investigate which coordinates system is used to code the peripersonal space during motor preparation if real objects rapidly approach the body. Our findings provide direct evidence for automatic hand-centred coding of visual space and suggest that peripersonal space may also serve to represent rapidly 3 approaching and potentially noxious objects, thus enabling the rapid selection of appropriate motor responses. These results clearly show that peripersonal space is a multisensori-motor interface that might have been selected through evolution for optimising the interactions between the body and the objects in the external world.

Peripersonal (reachable) and extrapersonal (beyond reach) space is linked to hand perception. Using a tool to reach farther than normal recalibrates previously unreachable space as peripersonal, evidenced by Intraparietal Sulcus (IPS) activity related to hand perception and lateral biases during line bisection. The current study looked at the role of a visual connection between the hand and body in the ability to manipulate objects within the extended area of reach. In an immersive virtual environment, participants bisected lines using a connected hand (via arm), a disconnected hand, or a floating dot. A rightward shift in bisection was seen only for the dot condition for far lines, indicating that it was the only "tool" incapable of extending peripersonal space.

Peripersonal (reachable) and extrapersonal (beyond reach) space is linked to hand perception. Using a tool to reach farther than normal recalibrates previously unreachable space as peripersonal, evidenced by Intraparietal Sulcus (IPS) activity related to hand perception and lateral biases during line bisection. The current study looked at the role of a visual connection between the hand and body in the ability to manipulate objects within the extended area of reach. In an immersive virtual environment, participants bisected lines using a connected hand (via arm), a disconnected hand, or a floating dot. A rightward shift in bisection was seen only for the dot condition for far lines, indicating that it was the only "tool" incapable of extending peripersonal space.

Notre habilité à interagir avec les objets du monde nécessite l’intégration d’informations provenant de différents canaux sensoriels, dans le cadre de la construction d’une représentation de l’espace en particulier des informations visuelles et tactiles. L’espace péri personnel et l’intégration visuo-tactile ont été l’objet d’importantes recherche récemment. Des études neuro physiologiques chez le primate non-humain ont montré l’existence de neurones bi modaux activés à la fois par des stimulations tactiles et par des stimulations visuelles si ces dernières étaient présentées près d’une partie du corps (par exemple la main). Il a été proposé que ces neurones bi-modaux constituent le substrat neuronal de la représentation de l’espace péri personnel. Les études neuropsychologiques menées chez des patients présentant une extinction cross-modale consécutive à une lésion pariétale droite ont permis de suggérer l’existence du même type de représentation de l’espace péri personnel chez l’homme. Les données issues des études en neuro imagerie fonctionnelle sont venues par la suite conforter cette idée. Plus récemment, à travers l’utilisation d’outils, des données acquises chez le primate humain et non humain ont révélé les propriétés dynamiques de cette représentation spatiale. Selon notre hypothèse la représentation de l’espace péri personnel est une interface présidant aux interactions du corps avec les objets du monde externe. Nous avons donc évalué le rôle et l’état de l’espace péri personnel lors de l’exécution de mouvements volontaires vers des objets (comme une simple saisie) et lors de mouvements involontaires d’évitement. Lors d’une première série d’expériences nous avons étudié les coordonnées spatiales du codage des objets qui soudainement se rapprochent du corps grâce à la mesure des potentiels évoqués moteurs. Cette étude a révélé que l’espace péri personnel joue un rôle dans la représentation des objets approchant le corps et dans la sélection des mouvements appropriés en réponse. Lors d’une seconde série d’expériences nous avons utilisé un paradigme d’interférence visuo-tactile couplé à l’enregistrement cinématique des mouvements de saisie afin d’examiner la représentation de l’espace péri personnel lors de 1 l’exécution d’actions volontaires. Cette approche novatrice nous a permis de mettre en évidence que l’action volontaire induit un recodage en ligne de l’interaction visuo-tactile dans l’espace de préhension. Ce recodage de l’action s’effectue en coordonnées centrées sur la partie du corps qui exécute l’action. En conclusion nos études expérimentales démontrent que l’espace péri personnel est une interface multi sensorielle qui a été sélectionnée à travers l’évolution non seulement pour la gestion des mouvements d’évitement et de défense mais également pour l’exécution d’actions volontaires. / Our ability to interact with the environment requires the integration of multisensory information for the construction of spatial representations. The peripersonal space (i.e., the sector of space closely surrounding one’s body) and the integrative processes between visual and tactile inputs originating from this sector of space have been at the center of recent years investigations. Neurophysiological studies provided evidence for the presence in the monkey brain of bimodal neurons, which are activated by tactile as well as visual information delivered near to a specific body part (e.g., the hand). Neuropsychological studies on right brain-damaged patients who present extinction and functional neuroimaging findings suggest the presence of similar bimodal systems in the human brain. Studies on the effects of tool-use on visual-tactile interaction revealed similar dynamic properties of the peripersonal space in monkeys and humans. The functional role of the multisensory coding of peripersonal space is, in our hypothesis, that of providing the brain with a sensori-motor interface for body-objects interactions. Thus, not only it could be involved in driving involuntary defensive movements in response to objects approaching the body, but could be also dynamically maintained and updated as a function of manual voluntary actions performed towards objects in the reaching space. We tested the hypothesis of an involvement of peripersonal space in executing both voluntary and defensive actions. To these aims, we joined a well known cross-modal congruency effect between visual and tactile information to a kinematic approach to demonstrate that voluntary grasping actions induce an on-line re-weighting of multisensory interactions in the peripersonal space. We additionally show that this modulation is handcentred. We also used a motor evoked potentials approach to investigate which coordinates system is used to code the peripersonal space during motor preparation if real objects rapidly approach the body. Our findings provide direct evidence for automatic hand-centred coding of visual space and suggest that peripersonal space may also serve to represent rapidly 3 approaching and potentially noxious objects, thus enabling the rapid selection of appropriate motor responses. These results clearly show that peripersonal space is a multisensori-motor interface that might have been selected through evolution for optimising the interactions between the body and the objects in the external world.

L'homme ne perçoit pas l'espace de manière homogène : le cerveau code l'espace proche du corps différemment de l'espace lointain. Cette distinction joue un rôle primordial notre comportement social : l'espace proche du corps, appelé espace péripersonnel (EPP), serait une zone de protection du corps, où la présence d'un individu est perçue comme une menace. L'EPP a été initialement décrit par la psychologie sociale et l'anthropologie, comme un facteur de la communication humaine. L'EPP a été plus tard décrit chez le singe par des études de neurophysiologie comme un espace codé par des neurones multisensoriels. Ces neurones déchargent uniquement en réponse à des évènements sensoriels situés à une distance limitée du corps du singe (qu'ils soient tactiles, visuels ou auditifs). L'ensemble de ces neurones multisensoriels code ainsi l'EPP tout autour du corps. Ce codage exclusif de l'EPP est crucial pour interagir avec le monde extérieur, car c'est dans cet espace que sont réalisées les actions visant à protéger le corps ou visant à atteindre des objets autour de soi. Le codage mutlisensoriel de l'EPP pendant des interactions sociales est à ce jour peu étudié. Dans ce travail de recherche, nous avons réalisé plusieurs études en vu d'identifier des facteurs contribuant à la perméabilité de l'EPP et ses aspects adaptatifs. Une première étude a examiné les frontières latérales de l'EPP chez des individus seuls, en mesurant l'interaction d'une source sonore dynamique s'approchant du corps avec le temps de détection de stimulations tactiles. Cette étude a montré des différences dans la taille de l'EPP entre les deux hémi-espaces, qui seraient liées à la latéralité manuelle. Une seconde étude a exploré les modulations de l'EPP dans des contextes sociaux. Elle a montré que l'EPP est modifié lorsque des individus réalisent une tâche en collaboration. La troisième étude est une recherche méthodologique qui vise à dépasser les limitations des paradigmes comportementaux utilisés actuellement pour mesurer l'EPP. Elle propose de nouvelles pistes pour évaluer comment les stimuli approchant le corps sont intégrés en fonction de leur distance et du contexte multisensoriel dans lequel ils sont traités. L'ensemble de ces travaux montre l'intérêt d'étudier l'intégration multisensorielle autour du corps dans l'espace 3D pour comprendre pleinement l'EPP, et les impacts potentiels de facteurs sociaux sur les processus multisensoriels de bas-niveaux. De plus, ces études soulignent l'importance pour les neurosciences sociales de développer des protocoles expérimentaux réellement sociaux, à plusieurs participants. / The space near the body, called peripersonal space (PPS), was originally studied in social psychology and anthropology as an important factor in interpersonal communication. It was later described by neurophysiological studies in monkeys as a space mapped with multisensory neurons. Those neurons discharge only when events are occurring near the body (be it tactile, visual or audio information), delineating the space that people consider as belonging to them. The human brain also codes events that are near the body differently from those that are farther away. This dedicated brain function is critical to interact satisfactorily with the external world, be it for defending oneself or to reach objects of interest. However, little is known about how this function is impacted by real social interactions. In this work, we have conducted several studies aiming at understanding the factors that contribute to the permeability and adaptive aspects of PPS. A first study examined lateral PPS for individuals in isolation, by measuring reaction time to tactile stimuli when an irrelevant sound is looming towards the body of the individual. It revealed an anisotropy of reaction time across hemispaces, that we could link to handedness. A second study explored the modulations of PPS in social contexts. It was found that minimal social instructions could influence the shape of peripersonal space, with a complex modification of behaviors in collaborative tasks that outreaches the handedness effect. The third study is a methodological investigation attempting to go beyond the limitations of the behavioral methods measuring PPS, and proposing a new direction to assess how stimuli coming towards the body are integrated according to their distance and the multisensory context in which they are processed. Taken together, our work emphasizes the importance of investigating multisensory integration in 3D space around the body to fully capture PPS mechanisms, and the potential impacts of social factors on low-level multisensory processes. Moreover, this research provides evidence that neurocognitive social investigations, in particular on space perception, benefit from going beyond the traditional isolated individual protocols towards actual live social interactive paradigms.