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When performing willed actions, we have the unified and coherent experience of owning and controlling our body. Body ownership is believed to emerge from the integration of coherent multisensory signals, while agency is believed to emerge from the coherence between predicted and perceived outcomes of actions. As a consequence, body ownership and agency can both be modulated by multisensory conflicts. The contribution of active movement generation to ownership and agency has not been parametrically explored. Here, we investigated the contribution of interaction force between the agent and the environment to the sense of hand ownership (SO) and the sense of hand agency (SA). By combining robotics and virtual reality, we manipulated the sensorimotor and visual information during immersive scenarios to induce and quantify altered states of SO and SA. First, we demonstrated that SO and SA could be successfully manipulated by our experimental paradigms. Second, we showed that interaction force strongly contributes to SA, but to a lesser extent to SO. Finally, we showed that SO and SA interact beyond their common multisensory basis. Our results, based on two independent studies, provide a direct link between sensorimotor interactions and subjective body experience and demonstrate a new dissociation between SO and SA., Scientific Reports, 11 (1), ISSN:2045-2322

Bodily and mental self-ascriptions are forms of first-person thought where a subject attributes physical properties and psychological states to herself. The body-ownership view argues that a necessary and sufficient condition on such self-ascriptions is the existence of causal links between a spatio-temporal body and the self-ascribed properties or states. However, since P.F. Strawson’s influential attack, this view has been dismissed as a bad philosophical idea. The goal of this brief piece is to outline the body-ownership view and neutralise two classic lines of objection against it: on the one hand, that the stance is incoherent; and, on the other, that it has counterintuitive implications. Resumen: Las auto-atribuciones corporales y mentales son formas de pensamiento en primera persona donde un sujeto se atribuye propiedades físicas y estados psicológicos a sí mismo. La teoría de posesión corporal sostiene que una condición necesaria y suficiente de tales auto-atribuciones es la existencia de conexiones causales entre un cuerpo espacio-temporal y las propiedades o estados auto-atribuidos. Sin embargo, desde el influyente ataque de P.F. Strawson a esta teoría, ella ha sido descartada como una mala idea filosófica. El objetivo de este breve artículo es delinear la teoría de posesión corporal y neutralizar dos líneas clásicas de crítica contra ella: por una parte, una según la cual la teoría es internamente incoherente; y, por otra, una según la cual ella tiene implicancias contraintuitivas.

Bodily and mental self-ascriptions are forms of first-person thought where a subject attributes physical properties and psychological states to herself. The body-ownership view argues that a necessary and sufficient condition on such self-ascriptions is the existence of causal links between a spatio-temporal body and the self-ascribed properties or states. However, since P.F. Strawson’s influential attack, this view has been dismissed as a bad philosophical idea. The goal of this brief piece is to outline the body-ownership view and neutralise two classic lines of objection against it: on the one hand, that the stance is incoherent; and, on the other, that it has counterintuitive implications.

For most patients with schizophrenia it is difficult to sufficiently participate in the community, largely due to deficits in social interaction. The decreased ability to interact with other people and understand them is affected by the way patients perceive themselves. As schizophrenia is seen as a disorder of fundamental self-disturbances, in this thesis a series of empirical studies explore how schizophrenia is related to components that are crucial for making a distinction between oneself and others, hereby focusing on the concepts of body ownership, self-agency, and empathy. The feeling of body-ownership and the feeling of self-agency are considered the most important aspects for basic self-experience and contribute to a feeling of presence and being. Therefore, using a Rubber Hand Illusion paradigm, we provide insight into disturbances in the feeling of body ownership in patients with schizophrenia and in adolescents at increased familial risk to develop the disease. Second, self-agency inferences can result from implicitly associated cues or situations that can unconsciously pre-activate or prime an outcome representation in the agent’s mind. As previous studies found that patients with schizophrenia show specific impairments in these prime-based self-agency inferences, which are particularly important in social behavior, the current thesis provides insight in this topic. Third, as empathic abilities are an important predictor for functional outcome in schizophrenia, our research aims to increase knowledge about its etiology by focusing on the role of the self-reflection network in the brain. Summarizing, this thesis contributes to our understanding of self-disturbances in patients with schizophrenia by using experimental set-ups.

For most patients with schizophrenia it is difficult to sufficiently participate in the community, largely due to deficits in social interaction. The decreased ability to interact with other people and understand them is affected by the way patients perceive themselves. As schizophrenia is seen as a disorder of fundamental self-disturbances, in this thesis a series of empirical studies explore how schizophrenia is related to components that are crucial for making a distinction between oneself and others, hereby focusing on the concepts of body ownership, self-agency, and empathy. The feeling of body-ownership and the feeling of self-agency are considered the most important aspects for basic self-experience and contribute to a feeling of presence and being. Therefore, using a Rubber Hand Illusion paradigm, we provide insight into disturbances in the feeling of body ownership in patients with schizophrenia and in adolescents at increased familial risk to develop the disease. Second, self-agency inferences can result from implicitly associated cues or situations that can unconsciously pre-activate or prime an outcome representation in the agent’s mind. As previous studies found that patients with schizophrenia show specific impairments in these prime-based self-agency inferences, which are particularly important in social behavior, the current thesis provides insight in this topic. Third, as empathic abilities are an important predictor for functional outcome in schizophrenia, our research aims to increase knowledge about its etiology by focusing on the role of the self-reflection network in the brain. Summarizing, this thesis contributes to our understanding of self-disturbances in patients with schizophrenia by using experimental set-ups.

Humans regularly feel a sense of agency (SoA) over events where the causal link between action and outcome is extremely indirect. We have investigated how intermediate (here, a robotic hand) events that intervene between action and outcome may alter SoA, using intentional binding measures. The robotic hand either performed the same movement as the participant (active congruent), or performed a similar movement with another finger (active incongruent). Binding was significantly reduced in the active incongruent relative to the active congruent condition, suggesting that altered embodiment influences SoA. However, binding effects were comparable between a condition where the robot hand made a congruent movement, and conditions where no robot hand was involved, suggesting that intermediate and embodied events do not reduce SoA. We suggest that human sense of agency involves both statistical associations between intentions and arbitrary outcomes, and an effector-specific matching of sensorimotor means used to achieve the outcome., SCOPUS: ar.j, info:eu-repo/semantics/published

International audience; While the Sense of Agency (SoA) has so far been predominantly characterised in VR as a component of the Sense of Embodiment, other communities (e.g., in psychology or neurosciences) have investigated the SoA from a different perspective proposing complementary theories. Yet, despite the acknowledged potential benefits of catching up with these theories a gap remains. This paper first aims to contribute to fill this gap by introducing a theory according to which the SoA can be divided into two components, the feeling and the judgment of agency, and relies on three principles, namely the principles of priority, exclusivity and consistency. We argue that this theory could provide insights on the factors influencing the SoA in VR systems. Second, we propose novel approaches to manipulate the SoA in controlled VR experiments (based on these three principles) as well as to measure the SoA, and more specifically its two components based on neurophysiological markers, using ElectroEncephaloGraphy (EEG). We claim that these approaches would enable us to deepen our understanding of the SoA in VR contexts. Finally, we validate these approaches in an experiment. Our results (N=24) suggest that our approach was successful in manipulating the SoA as the modulation of each of the three principles induced significant decreases of the SoA (measured using questionnaires). In addition, we recorded participants' EEG signals during the VR experiment, and neurophysiological markers of the SoA, potentially reflecting the feeling and judgment of agency specifically, were revealed. Our results also suggest that users' profile, more precisely their Locus of Control (LoC), influences their level of immersion and SoA.

[EN] Stroke can lead to motor impairments that can affect the body structure and restraint mobility. We hypothesize that brain lesions and their motor sequelae can distort the body schema, a sensorimotor map of body parts and elements in the peripersonal space through which human beings embody the reachable space and ready the body for forthcoming movements. Two main constructs have been identified in the embodiment mechanism: body-ownership, the sense that the body that one inhabits is his/her own, and agency, the sense that one can move and control his/her body. To test this, the present study simultaneously investigated different embodiment subcomponents (body-ownership, localization, and agency) and different neurophysiological measures (galvanic skin response, skin temperature, and surface electromyographic activity), and the interaction between them, in clinically-controlled hemiparetic individuals with stroke and in healthy subjects after the rubber hand illusion. Individuals with stroke reported significantly stronger body-ownership and agency and reduced increase of galvanic skin response, skin temperature, and muscular activity in the stimulated hand. We suggest that differences in embodiment could have been motivated by increased plasticity of the body schema and pathological predominance of the visual input over proprioception. We also suggest that differences in neurophysiological responses could have been promoted by a suppression of the reflex activity of the sympathetic nervous system and by the involvement of the premotor cortex in the reconfiguration of the body schema. These results could evidence a body schema plasticity promoted by the brain lesion and a main role of the premotor cortex in this mechanism., This work was supported by Ministerio de Economia y Competitividad of Spain (Project NeuroVR, TIN2013-44741-R, Project REACT, TIN2014-61975-EXP, and Grant BES-2014-068218), and by Universitat Politecnica de Valencia (Grant PAID-10-14).

[EN] The Rubber Hand Illusion (RHI) is a perceptual illusion that enables integration of artificial limbs into the body representation through combined multisensory integration. Most previous studies investigating the RHI have involved young healthy adults within a very narrow age range (typically 20-30 years old). The purpose of this paper was to determine the influence of age on the RHI. The RHI was performed on 93 healthy adults classified into three groups of age (20-35 years old, N = 41; 36-60 years old, N = 28; and 61-80 years old, N = 24), and its effects were measured with subjective (Embodiment of Rubber Hand Questionnaire), behavioral (proprioceptive drift), and physiological (changes in skin temperature and conductance) measures. There were neither significant differences among groups in any response, nor significant covariability or correlation between age and other measures (but for skin temperature), which suggests that the RHI elicits similar responses across different age groups in the adult phase., This study was funded, in part, by Ministerio de Economia y Competitividad of Spain (Grant BES-2014-068218) and Universitat Politecnica de Valencia (Grant PAID-10-14 and Grant PAID-10-16).

Our bodies are arguably one of the most intimate things we will ever know. But the comfort of our own physical boundaries can be altered in various ways. In this analysis, we will look at how vision contributes to the sense of owning a body by analysing six abnormal conditions: the rubber hand illusion, phantom limbs, somatoparaphrenia, the body-swap illusion, out-of-body experiences, and heautoscopy. Examinations of these experimental or pathological conditions has granted a greater understanding of body-ownership. It was discovered that vision plays different modulatory roles, being more intricately involved in full-body ownership than in part-body ownership. Vision appears to be highly connected to self-location and first-person perspective, which both are contributing factors in projecting the sense of ownership to an external location. In part-body ownership, however, vision can be overruled by other senses, such as proprioception. Though it is still able to contribute to the illusion of projecting ownership and proprioceptive displacement to a rubber hand.

A recent study has found that activity in multisensory brain areas, namely the premotor cortex, intraparietal cortex and the putamen, mirrors the vividness of ownership over a mannequin, induced by the body-swap illusion. Refereed/Peer-reviewed

The distinction between the sense of body-ownership and the sense of agency has attracted considerable empirical and theoretical interest lately. However, the respective contributions of multisensory and sensorimotor integration to these two varieties of body experience are still the subject of ongoing research. In this study, I examine the various methodological problems encountered in the empirical study of body-ownership and agency with the use of novel immersive virtual environment technology to investigate the interplay between sensory and motor information. More specifically, the focus is on testing the relative contributions and possible interactions of visual-tactile and visual-motor contingencies implemented under the same experimental protocol. The effect of this is supported by physiological measurements obtained from skin conductance responses and heart rate. The findings outline a relatively simple method for identifying the necessary and sufficient conditions for the experience of body-ownership and agency, as studied with immersive virtual environment technology.

A central feature of our consciousness is the experience of the self as a unified entity residing in a physical body, termed bodily self-consciousness. This phenomenon includes aspects such as the sense of owning a body (also known as body ownership) and has been suggested to arise from the integration of sensory signals from the body. Several studies have shown that temporally synchronous tactile stimulation of the real body and visual stimulation of a fake or virtual body can induce changes in bodily self-consciousness, typically resulting in a sense of illusory ownership over the fake body. The present study assessed the effect of anatomical congruency of visuo-tactile stimulation on bodily self-consciousness. A virtual body was presented and temporally synchronous visuo-tactile stroking was applied simultaneously to the participants' body and to the virtual body. We manipulated the anatomical locations of the visuo-tactile stroking (i.e., on the back, on the leg), resulting in congruent stroking (stroking was felt and seen on the back or the leg) or incongruent stroking (i.e., stroking was felt on the leg and seen on the back). We measured self-identification with the virtual body and self-location as well as skin temperature. Illusory self-identification with the avatar as well as changes in self-location were experienced in the congruent stroking conditions. Participants showed a decrease in skin temperature across several body locations during congruent stimulation. These data establish that the full-body illusion (FBI) alters bodily self-consciousness and instigates widespread physiological changes in the participant's body., Frontiers in Behavioral Neuroscience, 7, ISSN:1662-5153

International audience; Brain correlates of the sense of agency have recently received increased attention. However, the explorations remain largely restricted to the study of brains in isolation. The prototypical paradigm used so far consists of manipulating visual perception of own action while asking the subject to draw a distinction between self- versus externally caused action. However, the recent definition of agency as a multifactorial phenomenon combining bottom-up and top-down processes suggests the exploration of more complex situations. Notably there is a need of accounting for the dynamics of agency in a two-body context where we often experience the double faceted question of who is at the origin of what in an ongoing interaction. In a dyadic context of role switching indeed, each partner can feel body ownership, share a sense of agency and altogether alternate an ascription of the primacy of action to self and to other. To explore the brain correlates of these different aspects of agency, we recorded with dual EEG and video set-ups 22 subjects interacting via spontaneous versus induced imitation (II) of hand movements. The differences between the two conditions lie in the fact that the roles are either externally attributed (induced condition) or result from a negotiation between subjects (spontaneous condition). Results demonstrate dissociations between self- and other-ascription of action primacy in delta, alpha and beta frequency bands during the condition of II. By contrast a similar increase in the low gamma frequency band (38-47 Hz) was observed over the centro-parietal regions for the two roles in spontaneous imitation (SI). Taken together, the results highlight the different brain correlates of agency at play during live interactions.

Introduction. Aberrant experience of agency is characteristic of schizophrenia. An understanding of the neurobiological basis of such experience is therefore of considerable importance for developing successful models of the disease. We aimed to characterise the effects of ketamine, a drug model for psychosis, on sense of agency (SoA). SoA is associated with a subjective compression of the temporal interval between an action and its effects: This is known as "intentional binding". This action-effect binding provides an indirect measure of SoA. Previous research has found that the magnitude of binding is exaggerated in patients with schizophrenia. We therefore investigated whether ketamine administration to otherwise healthy adults induced a similar pattern of binding.Methods. 14 right-handed healthy participants (8 female; mean age 22.4 years) were given low-dose ketamine (100 ng/mL plasma) and completed the binding task. They also underwent structured clinical interviews.Results. Ketamine mimicked the performance of schizophrenia patients on the intentional binding task, significantly increasing binding relative to placebo. The size of this effect also correlated with aberrant bodily experiences engendered by the drug.Conclusions. These data suggest that ketamine may be able to mimic certain aberrant agency experiences that characterise schizophrenia. The link to individual changes in bodily experience suggests that the fundamental change produced by the drug has wider consequences in terms of individuals' experiences of their bodies and movements.

Artificial stimulation of the peripheral vestibular system has been shown to improve ownership of body parts in neurological patients, suggesting vestibular contributions to bodily self-consciousness. Here, we investigated whether galvanic vestibular stimulation (GVS) interferes with the mechanisms underlying ownership, touch, and the localization of one's own hand in healthy participants by using the "rubber hand illusion" paradigm. Our results show that left anodal GVS increases illusory ownership of the fake hand and illusory location of touch. We propose that these changes are due to vestibular interference with spatial and/or temporal mechanisms of visual-tactile integration leading to an enhancement of visual capture. As only left anodal GVS lead to such changes, and based on neurological data on body part ownership, we suggest that this vestibular interference is mediated by the right temporo-parietal junction and the posterior insula.

[PT] A violência doméstica contra as mulheres é uma realidade demasiado presente na sociedade contemporânea, sabendo-se muito pouco sobre todo o processo e, sobretudo, sobre as vítimas. É uma problemática de particular complexidade, por contar com múltiplos intervenientes, mas também pelas diferentes perspetivas teóricas que se podem adotar na sua compreensão. Neste artigo, fazemos uma revisão sobre a fenomenologia do corpo da mulher vítima de violência, considerando o corpo físico e psíquico, discutindo os processos de embodiment da violência e do trauma. Tentamos compreender como o corpo se coloca numa situação de agressão, e de que forma isso compromete o comportamento e a saúde da vítima, ou como podemos fazer do corpo uma ferramenta de empoderamento da mulher agredida. [EN] Domestic violence against women is a major reality in our present society, although our scares knowledge about all the process and, mostly, about the victims. It is quite a complex issue, because of its many characters, but also because there are a range of different theoretical perspectives for its comprehension. In this paper, we reviewed knowledge about phenomenology of the body, particularly the body of female victims of violence, taking in account the physical and psychic body, discussing the embodiment of violence and trauma. We try to understand how the body behaves in an aggressive situation, and how it compromises the battered woman behavior and health, or even how we can make from the body an empowerment resource.