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Neuropsychological disturbances in the sense of limb ownership provide unique opportunities to study the neurocognitive basis of body ownership. Previous small sample studies that showed discrete cortical lesions cannot explain why multisensory, affective, and cognitive manipulations alter disownership symptoms. We tested the novel hypothesis that disturbances in the sense of limb ownership would be associated not only with discrete cortical lesions but also with disconnections of white-matter tracts supporting specific functional networks. We drew on an advanced lesion-analysis and Bayesian statistics approach in 49 right-hemisphere patients (23 with and 26 without limb disownership). Our results reveal that disturbances in the sense of ownership are associated with lesions in the supramarginal gyrus and disconnections of a fronto-insular-parietal network, involving the frontal-insular and frontal inferior longitudinal tracts, confirming previous disconnection hypotheses. Together with previous behavioral and neuroanatomical results, these findings lead us to propose that the sense of body ownership involves the convergence of bottom-up, multisensory integration, and top-down monitoring of sensory salience based on contextual demands.

In animals, proper locomotion is crucial to find mates and foods and avoid predators or dangers. Multiple sensory systems detect external and internal cues and integrate them to modulate motor outputs. Proprioception is the internal sense of body position, and proprioceptive control of locomotion is essential to generate and maintain precise patterns of movement or gaits. This proprioceptive feedback system is conserved in many animal species and is mediated by stretch-sensitive receptors called proprioceptors. Recent studies have identified multiple proprioceptive neurons and proprioceptors and their roles in the locomotion of various model organisms. In this review we describe molecular and neuronal mechanisms underlying proprioceptive feedback systems in C. elegans, Drosophila, and mice. [BMB Reports 2021; 54(8): 393-402].

Hand interaction techniques in virtual reality often exploit visual dominance over proprioception to remap physical hand movements onto different virtual movements. However, when the offset between virtual and physical hands increases, the remapped virtual hand movements are hardly self-attributed, and the users become aware of the remapping. Interestingly, the sense of self-attribution of a body is called the sense of body ownership (SoBO) in the field of psychology, and the realistic the avatar, the stronger is the SoBO. Hence, we hypothesized that realistic avatars (i.e., human hands) can foster self-attribution of the remapped movements better than abstract avatars (i.e., spherical pointers), thus making the remapping less noticeable. In this article, we present an experiment in which participants repeatedly executed reaching movements with their right hand while different amounts of horizontal shifts were applied. We measured the remapping detection thresholds for each combination of shift directions (left or right) and avatar appearances (realistic or abstract). The results show that realistic avatars increased the detection threshold (i.e., lowered sensitivity) by 31.3 percent than the abstract avatars when the leftward shift was applied (i.e., when the hand moved in the direction away from the body-midline). In addition, the proprioceptive drift (i.e., the displacement of self-localization toward an avatar) was larger with realistic avatars for leftward shifts, indicating that visual information was given greater preference during visuo-proprioceptive integration in realistic avatars. Our findings quantifiably show that realistic avatars can make remapping less noticeable for larger mismatches between virtual and physical movements and can potentially improve a wide variety of hand-remapping techniques without changing the mapping itself.

This study aimed to verify whether visual-motor illusion changes the functional connectivity during kinesthetic motor imagery and the vividness of kinesthetic motor imagery. Twelve right-handed healthy adults participated in this study. All participants randomly performed both the illusion and observation conditions in 20 min, respectively. Illusion condition was induced kinesthetic illusion by viewing own finger movement video. Observation condition was observed own finger movement video. Before and after each condition, the brain activity of kinesthetic motor imagery was measured using functional near-infrared spectroscopy. The measure of brain activity under kinesthetic motor imagery was executed in five sets using block design. Under the kinesthetic motor imagery, participants were asked to imagine the movement of their right finger. Functional connectivity was analyzed during the kinesthetic motor imagery. In addition, after performing the task under kinesthetic motor imagery, the vividness of the kinesthetic motor imagery was measured using a visual analog scale. Furthermore, after each condition, the degree of kinesthetic illusion and sense of body ownership measured based on a seven-point Likert scale. Our results indicated that the functional connectivity during kinesthetic motor imagery was changed in the frontal-parietal network of the right hemisphere. The vividness of the kinesthetic motor imagery was significantly higher with the illusion condition compared with the observation condition. The degree of kinesthetic illusion and sense of body ownership were significantly higher with the illusion condition compared with the observation condition. In conclusion, the visual-motor illusion changes the functional connectivity during kinesthetic motor imagery and influences the vividness of kinesthetic motor imagery. The visual-motor illusion provides evidence that it improves motor imagery ability. VMI may be used in patients with impaired motor imagery.

During menopause, there is a hormonal imbalance that would lead to variety of menopausal symptoms such as hot flashes, weight gain, changes in the body shape, hair loss, hair becomes grayer and coarse, decreased elasticity of the skin, thinning of lining and dryness in the vagina, breast discomfort and urinary incontinence. These menopausal symptoms cause concern and discomfort for these women. It also affects their quality of life. The study aimed to explore the women's sense of body during their midlife years. A phenomenological-heuristic research design used in the study. Eight informants willingly participated in the study under an informal, semi-structured interview with the main question, "What are your experiences during midlife?" and "How did those experiences happened?" The transcribed verbatim were analyzed through the use of Moustakas method. The study revealed 7 main themes: (1) "I've changed…" (2) "What is bothering me?" (3) Looking back into the windows of the past (4) my weapons for my battle (5) Metamorphosis: A new conquest (6) Dreams: The paramount of my life. The study reflected the entirety of the participant's experiences. This study has shown that living the experience of wellness at menopause can accommodate the experience of change or symptoms. In this way the experience of menopausal change is not disruptive to the woman's continuity of experience, she continues to feel well and to do all the things she wants to do. Further recommendations are needed to enhance the understanding of the lived experience of women regarding their sense of body at midlife.

Common existing head-mounted displays (HMDs) for virtual reality (VR) provide users with a high presence and embodiment. However, the field of view (FoV) of a typical HMD for VR is about 90 to 110 [deg] in the diagonal direction and about 70 to 90 [deg] in the vertical direction, which is narrower than that of humans. Specifically, the downward FoV of conventional HMDs is too narrow to present the user avatar's body and feet. To address this problem, we have developed a novel HMD with a pair of additional display units to increase the downward FoV by approximately 60 ( $10+50$ ) [deg]. We comprehensively investigated the effects of the increased downward FoV on the sense of immersion that includes presence, sense of self-location (SoSL), sense of agency (SoA), and sense of body ownership (SoBO) during VR experience and on patterns of head movements and cybersickness as its secondary effects. As a result, it was clarified that the HMD with an increased FoV improved presence and SoSL. Also, it was confirmed that the user could see the object below with a head movement pattern close to the real behavior, and did not suffer from cybersickness. Moreover, the effect of the increased downward FoV on SoBO and SoA was limited since it was easier to perceive the misalignment between the real and virtual bodies.

This case study of a small police agency in the United States uses semi-structured interviews, a patrol officer survey, and observations, to examine the technological frames of managers and users f...

Our sense of body ownership relies on integrating different sensations according to their temporal and spatial congruency. Nevertheless, there is ongoing controversy about the role of affective congruency during multisensory integration, i.e. whether the stimuli to be perceived by the different sensory channels are congruent or incongruent in terms of their affective quality. In the present study, we applied a widely used multisensory integration paradigm, the Rubber Hand Illusion, to investigate the role of affective, top-down aspects of sensory congruency between visual and tactile modalities in the sense of body ownership. In Experiment 1 (N = 36), we touched participants with either soft or rough fabrics in their unseen hand, while they watched a rubber hand been touched synchronously with the same fabric or with a ‘hidden’ fabric of ‘uncertain roughness’. In Experiment 2 (N = 50), we used the same paradigm as in Experiment 1, but replaced the ‘uncertainty’ condition with an ‘incongruent’ one, in which participants saw the rubber hand being touched with a fabric of incongruent roughness and hence opposite valence. We found that certainty (Experiment 1) and congruency (Experiment 2) between the felt and vicariously perceived tactile affectivity led to higher subjective embodiment compared to uncertainty and incongruency, respectively, irrespective of any valence effect. Our results suggest that congruency in the affective top-down aspects of sensory stimulation is important to the multisensory integration process leading to embodiment, over and above temporal and spatial properties.

Amongst tetrapods, mechanoreceptors on the feet establish a sense of body placement and help to facilitate posture and biomechanics. Mechanoreceptors are necessary for stabilizing the body while navigating through changing terrains or responding to a sudden change in body mass and orientation. Lizards such as the leopard gecko (Eublepharis macularius) employ autotomy – a voluntary detachment of a portion of the tail – to escape predation. Tail autotomy represents a natural form of significant (and localized) mass loss. Semmes–Weinstein monofilaments were used to investigate the effect of tail autotomy (and subsequent tail regeneration) on tactile sensitivity of each appendage of the leopard gecko. Prior to autotomy, we identified site-specific differences in tactile sensitivity across the ventral surfaces of the hindlimbs, forelimbs and tail. Repeated monofilament testing of both control (tail-intact) and tail-loss geckos had a significant sensitization effect (i.e. decrease in tactile threshold, maintained over time) in all regions of interest except the palmar surfaces of the forelimbs in post-autotomy geckos, compared with baseline testing. Although the regenerated tail is not an exact replica of the original, tactile sensitivity is shown to be effectively restored at this site. Re-establishment of tactile sensitivity on the ventral surface of the regenerate tail points towards a (continued) role in predator detection.

International audience; Effective collaboration in immersive virtual environments requires to be able to communicate flawlessly using both verbal and non-verbal communication. We present two experiments investigating the impact of facial anthropomorphism on the sense of body ownership, avatar attractiveness, social presence and performance in two collaborative tasks. In the first experiment participants have to solve a construction game according to their partner’s instructions using three avatars presenting different facial properties. Results reveal no significant difference in terms of body ownership and social presence, but demonstrate significant differences in terms of attractiveness and completion duration of the collaborative task. Unexpectedly, correlation analyses also reveal a link between attractiveness and performance. The more attractive the avatar, the shorter the completion duration of the game. Our second experiment was designed to investigate further the potential impact of the task carried out on the sense of social presence using the same avatars. While we observed a very high sense of social presence in both tasks (asymmetric collaboration and negotiation) with every avatar, our results did not reveal significant difference between the three conditions. However, we observed statistically significant differences between the two task types. The scores of the co-presenceand of the perceived message understanding dimensions of social presence were higher during the negotiation task. The sense of social presence appears to be task sensitive, especially when non-verbal communication becomes more important during face-to-face interaction in immersive collaborative virtual environments.

Body ownership concerns what it is like to feel a body part or a full body as mine, and has become a prominent area of study. We propose that there is a closely related type of bodily self-consciousness largely neglected by researchers—experiential ownership. It refers to the sense that I am the one who is having a conscious experience. Are body ownership and experiential ownership actually the same phenomenon or are they genuinely different? In our experiments, the participant watched a rubber hand or someone else’s body from the first-person perspective and was touched either synchronously or asynchronously. The main findings: (1) The sense of body ownership was hindered in the asynchronous conditions of both the body-part and the full-body experiments. However, a strong sense of experiential ownership was observed in those conditions. (2) We found the opposite when the participants’ responses were measured after tactile stimulations had ceased for 5 s. In the synchronous conditions of another set of body-part and full-body experiments, only experiential ownership was blocked but not body ownership. These results demonstrate for the first time the double dissociation between body ownership and experiential ownership. Experiential ownership is indeed a distinct type of bodily self-consciousness.

Awareness of the body is essential for accurate motor control. However, how this awareness influences motor control is poorly understood. The awareness of the body includes awareness of visible body parts as one’s own (sense of body ownership) and awareness of voluntary actions over that visible body part (sense of agency). Here, I show that sense of agency over a visible hand improves the initiation of movement, regardless of sense of body ownership. The present study combined the moving rubber hand illusion, which allows experimental manipulation of agency and body ownership, and the finger-tracking paradigm, which allows behavioral quantification of motor control by the ability to coordinate eye with hand movements. This eye–hand coordination requires awareness of the hand to track the hand with the eye. I found that eye–hand coordination is improved when participants experience a sense of agency over a tracked artificial hand, regardless of their sense of body ownership. This improvement was selective for the initiation, but not maintenance, of eye–hand coordination. These results reveal that the prospective experience of explicit sense of agency improves motor control, suggesting that artificial manipulation of prospective agency may be beneficial to rehabilitation and sports training techniques.

Self-touch is considered important for bodily self-consciousness and self-other distinction and has been reported to improve clinical symptoms of disembodiment. To investigate the link between self-touch and disembodiment in healthy participants, we studied the effect of self-touch versus touch produced by another person (other-touch) on experimentally induced disembodiment. In a mixed reality paradigm, across two experiments, participants could see their own body and surroundings with a controllable visual delay and either stroked their own hand with a paintbrush or were stroked with it by the experimenter. Experiment 1 first assessed the sensitivity to temporal multimodal mismatches and delay-induced changes in the sense of body ownership in three conditions, namely self-touch, other-touch and hidden-self-touch (visually occluding the touching hand). In a second block, we compared phenomenological and physiological (threat response) measures of disembodiment between the self-touch and other-touch conditions. Experiment 2 roughly replicated the first block of Experiment 1 but included a condition in which participants performed the self-touch gesture without touching their hand. Such experiment attempted to control for the potential role of efferent signals. Our results show that increasing visual delay generally enhances the feeling of disembodiment, yet the decrease of body ownership is less pronounced during self-touch. For sensitivity to delay between conditions, however, diverging findings are discussed. This study provides evidence for the importance of self-touch in sustaining a healthy sense of body in the context of disembodiment.

Researchers investigating virtual/augmented reality have shown humans' marked adaptability, especially regarding our sense of body ownership; their cumulative findings have expanded the concept of what it means to have a body. Herein, we report the hand ownership illusion during "two views merged in." In our experiment, participants were presented two first-person perspective views of their arm overlapped, one was the live feed from a camera and the other was a playback video of the same situation, slightly shifted toward one side. The relative visibility of these two views and synchrony of tactile stimulation were manipulated. Participants' level of embodiment was evaluated using a questionnaire and proprioceptive drift. The results show that the likelihood of embodying the virtual hand is affected by the relative visibility of the two views and synchrony of the tactile events. We observed especially strong hand ownership of the virtual hand in the context of high virtual hand visibility with synchronous tactile stimulation.

The multisensory regions in frontoparietal cortices play a crucial role in the sense of body and self. Disrupting this sense may lead to a feeling of disembodiment, or more generally, a sense of disownership. Experimentally, this altered consciousness disappears during illusory own-body perceptions, increasing the intensity of perceived ownership for an external virtual limb. In many clinical conditions, particularly in individuals with a discontinuous or absent sense of bodily awareness, the brain may effortlessly create a convincing feeling of body ownership over a surrogate body or body part. The immediate visual input dominates the current bodily state and induces rapid plastic adaptation that reconfigures the dynamics of bodily representation, allowing the brain to acquire an alternative sense of body and self. Investigating strategies to deconstruct the lack of a normal sense of bodily ownership, especially after a neurological injury, may aid the selection of appropriate clinical treatment.

The sense of body ownership is a fundamental feature that refers to the ability to recognize our body as our own, allowing us to interact properly with the outside world. Usually, it is explored by means of the Rubber Hand Illusion (RHI) during which a dummy hand is incorporated in the mental representation of one's own body throughout a multisensory (visuo-tactile) integration mechanism. Particular attention has been paid to the neurofunctional counterparts of this mechanism highlighting the pivotal role of an occipito-parieto-frontal network involving the Ventral Premotor area (PMv). To date, the specific role of the PMv in generating the sense of ownership is still unknown. In this study, we aimed at exploring the role of PMv in generating and experiencing the RHI. Off-line repetitive Transcranial Magnetic Stimulation (rTMS) was applied to a group of 24 healthy participants whilst changes in proprioceptive judgment and self-reported illusion sensations were collected and analysed separately. The PMv was not directly implicated in generating the sense of ownership. Indeed, its inhibition affected the explicit detection of the visuo-tactile congruence without interfering with the illusion experience itself. We hypothesized that the conscious visuo-tactile congruence detection may be independent from the conscious illusion experience. Also, our results support the view that the RHI grounds on a complex interaction between bottom-up and top-down processes, as the visuo-tactile integration per se may be not sufficient to trigger the subjective illusion.

In the rubber hand illusion (RHI), participants view a rubber hand that is stroked synchronously with their real, hidden hand. This procedure results in experiencing an increased sense of ownership over the rubber hand and demonstrates how multisensory information (vision, touch) can influence the sense of body ownership. However, it has also been suggested that a (lack of) sense of ownership over an own body part may in turn influence bodily processes. This suggestion has previously been supported by the observation that a decrease in skin temperature in the real hand correlated with ownership over the rubber hand. However, this finding has not been consistently replicated. Our lab has conducted several studies in which we recorded temperature of the hands during the RHI using various measures and in different circumstances, including continuous temperature measurements in a temperature-controlled room. An overall analysis of our results, covering five attempts to replicate the traditional RHI experiment and totalling 167 participants, does not show a reliable cooling of the real hand during the RHI. We discuss this failure to replicate and consider several possible explanations for inconsistencies between reports of hand temperature during the RHI.

The main aim of the study discussed in the present paper was to explore the role of disturbances of bodily experience (of the sense of body ownership) in the regulation of a general emotional state. An attempt was made to verify the hypothesis that the autonomic emotional response (i.e. the objective state of stress) and the subjective sense of stress in schizophrenic subjects would be markedly weakened due to the Rubber Hand Illusion, whereas it was suggested that no such change would appear in the control group consisting of healthy subjects. In the 64 subjects who participated in the study (31 schizophrenic subjects and 33 subjects with no diagnosed mental condition), general emotional state was measured before and after the induction of the Rubber Hand Illusion, with the general emotional state understood as the objective state (electrodermal response) and the subjective state (the sense of stress or relaxation). Experimentally-induced change in the sense of body ownership appeared to be a factor regulating the subjective and the objective emotional states in all subjects, although the type of change differed significantly between the groups. In the schizophrenic group, the induction of the Rubber Hand Illusion substantially reduced the subjective and objective states of stress, whilst in the control group an intensified electrodermal response was observed (objective state of stress), with the subjective emotional state remaining unaltered.

Body ownership can be experimentally investigated with the rubber hand illusion (RHI), in which watching a rubber hand stroked synchronously with one’s own hidden hand induces a feeling of ownership over the rubber hand. The aim of this study was to investigate response to the RHI in high (N = 21) and low (N = 19) hypnotizable individuals in normal waking state and in hypnosis. Response to the RHI was measured via a question on the illusory feeling of ownership and with proprioceptive drift. The Highs expressed an overall feeling of more ownership over the rubber hand in both the normal waking state and hypnosis, although both groups gave higher ownership scores after synchronous than after asynchronous stroking and the difference between conditions was similar across groups. Conversely, the proprioceptive drift appeared to be differentially modulated by hypnosis and hypnotic suggestibility: it was increased in the Highs and decreased in the Lows after hypnosis induction. These findings hint at an interplay between hypnotic suggestibility and hypnosis in modulating response to the RHI. The selective breakdown of proprioceptive drift among the Lows suggests resistance to recalibrate one’s own limb in hypnosis.

Patients with schizophrenia report a wide range of anomalous body experiences. According to the basic symptom model of schizophrenia, disturbances of body perception and awareness are among the most powerful predictors of the changes in the subjective experience of the self in schizophrenia. In this study we first investigated the body structural representation (BSR), a specific aspect of body awareness, and its association to basic symptoms in patients with schizophrenia. Using a finger localization task, we found that patients are significantly less accurate than healthy controls when asked to identify pairs of fingers touched by the experimenter, when the hand is hidden from view. Most importantly, patients' performance at the finger localization task was negatively associated to basic symptoms: the worse the individual accuracy, the higher the SPI-A total score. Moreover, the accuracy at the finger localization task was also negatively correlated with the malleability of the sense of body ownership: the less the individual ability to localize fingers, the stronger the rubber hand illusion. These results are in agreement with the idea that self-disorders in schizophrenia reveal a disconnectedness that can be regarded as a problem of disembodiment and traced back to abnormal body experiences.

A sense of ownership over one's own body is essential for effective interaction with the world: acting upon objects or communicating with others relies on distinguishing between the parts of the world that constitute our self, and the parts of the world that do not. The sense of body ownership is frequently associated with activity in the ventral premotor cortex, intraparietal sulcus, and insula (Grivaz et al., 2017), and is believed to stem from multisensory integration (Ehrsson, 2012): congruent sensory signals are combined to provide a feeling of bodily self that is distinct from the surrounding environment. This is emphasized by the rubber hand illusion (RHI), in which synchronous, but not asynchronous, stroking of a rubber hand and the real hand (which is hidden from view) can induce a sense of ownership over the false limb (Botvinick and Cohen, 1998).

The motion-sensing research of large VR amusement equipment mainly includes two aspects of product hardware and product motion content. At present, the equipment experience of this category has the characteristics of diversity and complexity. This paper proposes a model based on analytic hierarchy process (AHP) to explore the key factors leading to poor experience. Firstly, APH is introduced to classify the factors of motion-sensing factors to quantify the influencing factors and select the main factors that cause bad experience. Secondly, the experimental results are compared to verify the accuracy of the ranking of the influencing factors in the model. The research shows that the influence of product motion content factors on the sense of body is greater than the hardware characteristics of the product, but the research results have certain limitations.

Proprioception, the sense of body position, movement, and associated forces, remains poorly understood, despite its critical role in movement. Most studies of area 2, a proprioceptive area of somatosensory cortex, have simply compared neurons’ activities to the movement of the hand through space. By using motion tracking, we sought to elaborate this relationship by characterizing how area 2 activity relates to whole arm movements. We found that a whole-arm model, unlike classic models, successfully predicted how features of neural activity changed as monkeys reached to targets in two workspaces. However, when we then evaluated this whole-arm model across active and passive movements, we found that many neurons did not consistently represent the whole arm over both conditions. These results suggest that 1) neural activity in area 2 includes representation of the whole arm during reaching and 2) many of these neurons represented limb state differently during active and passive movements.

The loss of body ownership, the feeling that your body and its limbs no longer belong to you, presents a severe clinical condition that has proven difficult to study directly. We here propose a novel paradigm using mixed reality to interfere with natural embodiment using temporally conflicting sensory signals from the own hand. In Experiment 1 we investigated how such a mismatch affects phenomenological and physiological aspects of embodiment, and identified its most important dimensions using a principle component analysis. The results suggest that such a mismatch induces a strong reduction in embodiment accompanied by an increase in feelings of disownership and deafference, which was, however, not reflected in physiological changes. In Experiment 2 we refined the paradigm to measure perceptual thresholds for temporal mismatches and compared how different multimodal, mismatching information alters the sense of embodiment. The results showed that while visual delay decreased embodiment both while actively moving and during passive touch, the effect was stronger for the former. Our results extend previous findings as they demonstrate that a sense of disembodiment can be induced through controlled multimodal mismatches about one’s own body and more so during active movement as compared to passive touch. Based on the ecologically more valid protocol we propose here, we argue that such a sense of disembodiment may fundamentally differ from disownership sensations as discussed in the rubber hand illusion literature, and emphasize its clinical relevance. This might importantly advance the current debate on the relative contribution of different modalities to our sense of body and its plasticity.

Body ownership illusion can lead to give a user a feeling of becoming an avatar as if it was their own body. Furthermore, existing studies have reported that an avatar's appearance can affect a user's behavior, attitude and mental condition. Almost all studies thus far have been focused on a human-like avatar, not that of an animal avatar. Unlike a human, it can be expected that the bird avatar can leads to give psychological effects in a flight experience, because a bird has flight ability. Our previous study reported that the bird avatar enhances the sense of flight significantly (i.e. participants feel as though they are flying in the sky.) than a human avatar in a flight experience. In this present work, we investigate about changes in attitudes with the fear of heights. We conduct experiments where an avatar is raised to a specific altitude after inducing the sense of body ownership. There are no significant differences between conditions. However, the bird avatar is rated higher than control condition in some questionnaire items. In particular, becoming a bird avatar decreases the subjective fear of heights.

This article seeks to explore the determinants of the sense of body boundaries and its implications for body self- relation in psychosomatic patients - patients with irritable bowel syndrome (IBS) as well as psoriasis and atopic dermatitis. Stepwise regression analysis and paths analysis were carried out. The most significant condition affecting the strength of the sense of body boundaries among IBS patients is their sensitivity to the violation of self- boundaries in the dimension of the social self. Likewise, among patients with skin diseases, the most important factor is their style of cognitive functioning (field independence). Furthermore, both similarities and differences have been found in the groups involved in the research in terms of determinants of the sense of body boundaries, as well as in comparison with the results from healthy patients. The results which were obtained indicated that the greater the strength of the sense of body boundaries in IBS patients, the greater its positive impact on the assessment of the patients’ own health, their physical attractiveness and comfort from touch, in a similar way to that in healthy people. As far as patients with psoriasis and atopic dermatitis are concerned, the sense of body boundaries was revealed to have a positive impact on the level of health orientation: active involvement with either maintaining or improving the health condition.

Disturbances in body experience are described as key schizophrenia symptoms and early disease predictors. In case studies, different disorders relating to body experience are presented, but only a few empirical studies have aimed to distinguish the characteristics of body experience in schizophrenia, and these have been selected arbitrarily and without reference to cohesive theoretical model. To integrate this fragmentary approach, we propose a body self (BS) model, composed of: functions; representations (e.g., body image); and sense of body identity. The aim of the study was to determine whether the BS differentiates schizophrenic patients from healthy controls, and to investigate the relations between aspects of BS and a history of illness and clinical characteristics. The Body Self Questionnaire and the Positive and Negative Syndrome Scale were administered to 63 schizophrenic patients and 63 healthy subjects. The difference was found in the functions of the body-self (perceiving, interpreting, and regulating body experience), in the sense of body identity, and in one of three aspects of body image explored (e.g., acceptance of biological sex). Disturbances in BS were related to positive symptoms and to the number of hospitalizations for other diseases. Together, the results demonstrate that schizophrenia is more body experience than body image disorder, since the negative emotional attitude towards the body and acceptance of fitness were not distinctive for schizophrenia. The link between the disturbances in BS and the number of nonpsychiatric hospitalizations suggests that misinterpretation of body experiences in schizophrenia can promote a search for medical attention.

CelGłównym celem prezentowanych badań była eksploracja zjawiska podatności na zakłócenia poczucia własności swojego ciała, wywoływanego eksperymentalnie u osób chorych na schizofrenię. Dążono do odpowiedzi na następujące pytania badawcze: 1) Czy RHI w grupie osób ze schizofrenią jest znacząco bardziej intensywna niż w grupie osób bez diagnozy choroby psychicznej? 2) Czy zaburzenia poczucia własności ciała pozostają w istotnym związku z poziomem organizacji osobowości, wyrażonym konstelacją najczęściej uruchamianych mechanizmów obronnych?, oraz 3) Czy zaburzenia poczucia własności ciała wiążą się z najczęstszym uruchamianiem konkretnych mechanizmów obronnych?MetodaW badaniach wzięły udział 64 osoby, w tym 31 osób z diagnozą schizofrenii wg ICD-10 (93,5% typ paranoidalny i 6,5% typ zdezorganizowany) oraz 33 bez diagnozy choroby psychicznej. Badania przeprowadzone zostały w paradygmacie Iluzji Gumowej Ręki (RHI). Wykorzystane zostały następujące narzędzia badawcze: Kwestionariusz RHI Botvinicka i Cohena oraz Kwestionariusz Stylów Obronnych Bonda.WynikiMiędzy grupą kontrolna a grupą osób ze schizofrenią stwierdzono istotne różnice: 1) w intensywności RHI (F(1, 62) = 121,86; p < 0,001), jak również 2) na poziomie mechanizmów neurotycznych (F(1, 62) = 28,21; p < 0,001) i mechanizmów niedojrzałych (F(1, 62) = 36,71; p < 0,001). W grupie osób ze schizofrenią najintensywniej uruchamiane są mechanizmy z grupy niedojrzałych, natomiast w grupie kontrolnej dominującymi w konstelacji mechanizmów obronnych są mechanizmy z grupy dojrzałych i neurotycznych.WnioskiOsoby ze schizofrenią znacznie intensywniej, w porównaniu do osób z grupy kontrolnej, ulegają zakłóceniom poczucia własności ciała. Intensywność RHI ma związek z poziomem organizacji osobowości, oraz z najczęstszym uruchamianiem mechanizmów z grupy niedojrzałych, zwłaszcza fantazji schizoidalnych i projekcji.

synopsis The aim of the study was to compare chosen aspects of body image and lifestyle in female students from Poland and Japan. The study was attended exclusively by women due to the criterion of homogeneity of the research group and the importance of research variables in the study area characterized by female population. Students (N = 203) completed a questionnaire about self-evaluation of appearance, preferred pattern of female attractiveness, physical activity, nutrition, and mental hygiene. Differences between groups were related to: sense of body proportionality, imitation of the model of attractiveness presented in media, ideal of femininity, ways to improve appearance, the most important aspect of body, the most important attribute of femininity, leisure time activities, the reason for dieting, kind of food eaten most frequently, places of buying of prepared meals. Students from Poland and Japan were similar in self-evaluation of their own appearance and mental hygiene. However, they differed in their preferred model of physical attractiveness and in some aspects of nutrition and physical activities.

Right-handed people show an advantage in detecting a delay in visual feedback concerning an active movement of their right hand when it is viewed in a natural perspective compared to when it is seen as if viewing another person's hand (Hoover and Harris in Exp Brain Res 233:1053-1060, 2012. doi: 10.1007/s00221-014-4181-9 ; Exp Brain Res 222:389-397, 2015a. doi: 10.1007/s00221-012-3224-3 ). This self-advantage is unique to their dominant hand and may reflect an enhanced sense of ownership which contributes to how right-handed people relate to the world. Here we asked whether left-handers show the same pattern of performance for their dominant hand. We measured the minimum delay that could be detected by 29 left-handers when viewing either their dominant or non-dominant hand from 'self' or 'other' perspectives and compared their thresholds to an age-matched sample of 22 right-handers. Right-handers showed a significant signature self-advantage of 19 ms when viewing their dominant hand in an expected 'self' perspective compared to 'other' perspectives. Left-handers, however, showed no such advantage for either their dominant or non-dominant hand. This lack of self-advantage in detecting delayed visual feedback might indicate a less secure sense of body ownership amongst left-handers.

Humans experience their own body as unitary and monolithic in nature. However, recent findings in cognitive neuroscience seem to suggest that body awareness has a complex and multifaceted structure that can be dissociated in several subcomponents, possibly underpinned by different brain circuits. In the present paper, we focus on a recently reported neuropsychological disorder of body ownership in which patients misattribute to themselves someone else's arm and its movements. As first, we briefly review the clinical and functional features of this disorder. Secondly, we attempt to explain the nature of the delusion and to gain new hints regarding the mechanisms subserving the construction and the maintenance of the sense of body ownership in the intact brain functioning.

Proprioception, the sense of body position, is essential for movement planning and postural control. However, its clinical assessment after stroke is generally rudimentary, limiting the design of personalized therapy regimes. In this study, we analyze the sensitivity of robotic metrics in comparison to clinical scales for proprioceptive assessment. Thirteen patients were screened with the Erasmus MC Nottingham Sensory Assessment and with a passive Joint Position Matching task by means of a wrist robot at hospital admission, discharge and 1-month follow-up. While the clinical test did not show significant differences across sessions, robotic metrics revealed that proprioceptive accuracy improved during the rehabilitation period, while improvements in proprioceptive precision required a longer time to occur and were noticeable in the follow-up session.

We present Ownershift, an interaction technique for easing overhead manipulation in virtual reality, while preserving the illusion that the virtual hand is the user's own hand. In contrast to previous approaches, this technique does not alter the mapping of the virtual hand position for initial reaching movements towards the target. Instead, the virtual hand space is only shifted gradually if interaction with the overhead target requires an extended amount of time. While users perceive their virtual hand as operating overhead, their physical hand moves gradually to a less strained position at waist level. We evaluated the technique in a user study and show that Ownershift significantly reduces the physical strain of overhead interactions, while only slightly reducing task performance and the sense of body ownership of the virtual hand. published

Our sense of body ownership relies on integrating different sensations according to their temporal and spatial congruency. Nevertheless, there is ongoing controversy about the role of affective congruency during multisensory integration, i.e. whether the stimuli to be perceived by the different sensory channels are congruent or incongruent in terms of their affective quality. In the present study, we applied a widely used multisensory integration paradigm, the Rubber Hand Illusion, to investigate the role of affective, top-down aspects of sensory congruency between visual and tactile modalities in the sense of body ownership. In Experiment 1 (N = 36), we touched participants with either soft or rough fabrics in their unseen hand, while they watched a rubber hand been touched synchronously with the same fabric or with a ‘hidden’ fabric of ‘uncertain roughness’. In Experiment 2 (N = 50), we used the same paradigm as in Experiment 1, but replaced the ‘uncertainty’ condition with an ‘incongruent’ one, in which participants saw the rubber hand being touched with a fabric of incongruent roughness and hence opposite valence. We found that certainty (Experiment 1) and congruency (Experiment 2) between the felt and vicariously perceived tactile affectivity led to higher subjective embodiment compared to uncertainty and incongruency, respectively, irrespective of any valence effect. Our results suggest that congruency in the affective top-down aspects of sensory stimulation is important to the multisensory integration process leading to embodiment, over and above temporal and spatial properties.

The vestibular system plays a pivotal role in behavioural and physiological aspects of body representation. If on the one hand, the stimulation of the vestibular system in healthy subjects provokes body representation distortions, accompanied by a decrease of body temperature, on the other hand, in brain-damaged patients it transiently restores body representation disorders. So far, the physiological counterpart of such behavioural amelioration on patients has never been explored. Here we aimed at investigating body temperature variations following Caloric Vestibular Stimulation (CVS), in a patient affected by somatoparaphrenia who regained the sense of body part ownership after the stimulation. Results showed an increase in body temperature after CVS, which also correlated with the temporary restored sense of limb ownership. Our results support the idea that physiological signals are fundamental to maintain a coherent mental representation of the body.

Currently, it is still debated whether, how and to what extent movements contribute to the sense of body ownership (i.e., the feeling that one’s body belongs to oneself). To answer this question, here we examined if a prolonged increase of the amount of movements affects body ownership. Specifically, we administered the rubber hand illusion paradigm within a natural condition of long-term motor practice, namely in expert pianists. We compared the illusory effects of both static (visuotactile stimulation) and dynamic (active/passive movements) versions of that paradigm in a group of expert pianists and a group of non-musicians. The illusion was measured behaviorally (proprioceptive drift) and subjectively (questionnaire). Our results showed that pianists were significantly less susceptible to any type of the illusion, compared to the non-musicians. Moreover, they did not experience the illusion in general (presenting neither the proprioceptive drift, nor the subjective feeling of ownership). These findings suggest that the increased amount of motor-related afferent and efferent signals does affect the construction and the coherence of body ownership, thus showing the role of movements in this process.

Tattooing offers expanded possibilities for creative expression for women who have undergone mastectomies and breast reconstruction surgeries. Tattoo techniques for areola restoration, such as repigmentation, do not address breast asymmetry or heavy scarring, but breast tattoos can embolden a woman's sexuality, self-confidence, and sense of body reclamation, as well as strengthen her postsurgical capacity for relating to her breasts and expressing her identity. There are many factors involved when a tattoo artist is asked to design an image for a patient. This article describes how I apply my artistic and trade talent to help mastectomy patients creatively reach beyond the limitations of surgical reconstruction possibilities.