scholarly journals Remote hand: Hand-centered peripersonal space transfers to a disconnected hand avatar

2021 ◽  
Author(s):  
Daisuke Mine ◽  
Kazuhiko Yokosawa
Keyword(s):  
Virtual Environment ◽  
Body Representation ◽  
Peripersonal Space ◽  
The Body ◽  
The Real ◽  
Novel Technique ◽  
Near Space ◽  
Behavioral Evidence ◽  
Real Hand

The space surrounding our body is called peripersonal space (PPS). It has been reported that visuo-tactile facilitation occurs more strongly within PPS than outside PPS. Furthermore, previous research has revealed several methods by which PPS can be extended. The present study provides the first behavioral evidence of the transfer of PPS in a virtual environment by a novel technique. PPS representation was investigated using a remote-controlled hand avatar presented far from their body in a virtual environment. Participants showed strongest visuo-tactile facilitation at the far space around the remote hand and no facilitation at the near space around the real hand, suggesting that PPS transfers from near the body to the space around the hand avatar. The present results extend previous findings of the plasticity of PPS and demonstrate flexibility of PPS representation beyond the physical and anatomical limits of body representation.

scholarly journals Capturing the dynamics of peripersonal space by integrating sound propagation properties and expectancy effects

2019 ◽  
Author(s):  
Lise Hobeika ◽  
Marine Taffou ◽  
Thibaut Carpentier ◽  
Olivier Warusfel ◽  
Isabelle Viaud-Delmon
Keyword(s):  
Sound Propagation ◽  
Current Method ◽  
Peripersonal Space ◽  
The Body ◽  
Logarithmic Scale ◽  
List Type ◽  
Expectancy Effects ◽  
Near Space ◽  
Propagation Properties ◽  
Tactile Integration

AbstractHighlightsLogarithmically distributed auditory distances provides an apt granularity of PPSMeasuring expectation helps to interpret behavioral impact of audiotactile integrationTactile RTs follows a logarithmic decrease due to audiotactile integrationPeripersonal space is better characterized and quantified with this refinementBackgroundHumans perceive near space and far space differently. Peripersonal space, i.e. the space directly surrounding the body, is often studied using paradigms based on auditory-tactile integration. In these paradigms, reaction time to a tactile stimulus is measured in the presence of a concurrent auditory looming stimulus.New MethodWe propose here to refine the experimental procedure considering sound propagation properties in order to improve granularity and relevance of auditory-tactile integration measures. We used a logarithmic distribution of distances for this purpose. We also want to disentangle behavioral contributions of the targeted audiotactile integration mechanisms from expectancy effects. To this aim, we added to the protocol a baseline with a fixed sound distance.ResultsExpectation contributed significantly to overall behavioral responses. Subtracting it isolated the audiotactile effect due to the stimulus proximity. This revealed that audiotactile integration effects have to be tested on a logarithmic scale of distances, and that they follow a linear variation on this scale.Comparison with Existing Method(s)The granularity of the current method is more relevant, providing higher spatial resolution in the vicinity of the body. Furthermore, most of the existing methods propose a sigmoid fitting, which rests on the intuitive framework that PPS is an in-or-out zone. Our results suggest that behavioral effects follow a logarithmic decrease, thus a response graduated in space.ConclusionsThe proposed protocol design and method of analysis contribute to refine the experimental investigation of the factors influencing and modifying multisensory integration phenomena in the space surrounding the body.

scholarly journals Cortical networks for encoding near and far space in the non-human primate

2018 ◽  
Author(s):  
Justine Cléry ◽  
Olivier Guipponi ◽  
Soline Odouard ◽  
Claire Wardak ◽  
Suliann Ben Hamed
Keyword(s):  
Personal Space ◽  
Peripersonal Space ◽  
The Body ◽  
The Other ◽  
Space Representation ◽  
List Type ◽  
Cortical Networks ◽  
Near Space ◽  
Space Processing ◽  
Human Primate

AbstractWhile extra-personal space is often erroneously considered as a unique entity, early neuropsychological studies report a dissociation between near and far space processing both in humans and in monkeys. Here, we use functional MRI in a naturalistic 3D environment to describe the non-human primate near and far space cortical networks. We describe the co-occurrence of two extended functional networks respectively dedicated to near and far space processing. Specifically, far space processing involves occipital, temporal, parietal, posterior cingulate as well as orbitofrontal regions not activated by near space, possibly subserving the processing of the shape and identity of objects. In contrast, near space processing involves temporal, parietal and prefrontal regions not activated by far space, possibly subserving the preparation of an arm/hand mediated action in this proximal space. Interestingly, this network also involves somatosensory regions, suggesting a cross-modal anticipation of touch by a nearby object. Last, we also describe cortical regions that process both far and near space with a preference for one or the other. This suggests a continuous encoding of relative distance to the body, in the form of a far-to-near gradient. We propose that these cortical gradients in space representation subserve the physically delineable peripersonal spaces described in numerous psychology and psychophysics studies.HighlightsNear space processing involves temporal, parietal and prefrontal regions.Far space activates occipital, temporal, parietal, cingulate & orbitofrontal areas.Most regions process both far & near space, with a preference for one or the other.Far-to-near gradient may subserve behavioral changes in peripersonal space size.

scholarly journals The supernumerary rubber hand illusion revisited: perceived duplication of limbs and visuotactile events

2020 ◽  
Author(s):  
Chenggui Fan ◽  
H. Henrik Ehrsson
Keyword(s):  
Cognitive Neuroscience ◽  
Body Representation ◽  
Rubber Hand Illusion ◽  
Body Ownership ◽  
Rubber Hand ◽  
Real Right ◽  
The Real ◽  
Skin Conductance Responses ◽  
Supernumerary Limbs ◽  
Real Hand

A controversial and unresolved issue in cognitive neuroscience is whether humans can experience supernumerary limbs as part of their own body. Some previous experiments have claimed that it is possible to elicit supernumerary hand illusions based on modified versions of the rubber hand illusion. However, other studies have provided conflicting results that suggest that only one rubber hand can be perceived as one’s own. To address this issue, we developed a supernumerary hand illusion paradigm that allowed us to disambiguate ownership of individual rubber hands from simultaneous ownership of two fake hands. In our setup, the participant’s real right hand was hidden under a platform, while two identical right rubber hands were placed in parallel on top of the platform in direct view of the participant. We applied synchronous strokes to both rubber hands and the real hand (SS), synchronous strokes to one rubber hand and the real hand and asynchronous strokes to the other model hand (AS and SA) or asynchronous strokes to both fake hands in relation to the real hand (AA). Our results demonstrate that a genuine illusion of owning two rubber hands can be elicited and that such a supernumerary hand illusion can be isolated from the sense of ownership of a single rubber hand both in terms of questionnaire ratings and threat-evoked skin conductance responses (SCRs). These findings advance our knowledge about the dynamic flexibility and fundamental constraints of body representation and emphasize the importance of correlated afferent signals for causal inference in body ownership.

scholarly journals How to lose a hand: Sensory updating drives disembodiment

2020 ◽  
Author(s):  
Roland Pfister ◽  
Annika L. Klaffehn ◽  
Andreas Kalckert ◽  
Wilfried Kunde ◽  
David Dignath
Keyword(s):  
Multisensory Integration ◽  
Body Representation ◽  
The Body ◽  
Rubber Hand ◽  
Body Representations ◽  
Dynamic View ◽  
Single Instance ◽  
Multisensory Input ◽  
To Receive ◽  
Real Hand

AbstractBody representations are readily expanded based on sensorimotor experience. A dynamic view of body representations, however, holds that these representations cannot only be expanded but that they can also be narrowed down by disembodying elements of the body representation that are no longer warranted. Here we induced illusory ownership in terms of a moving rubber hand illusion and studied the maintenance of this illusion across different conditions. We observed ownership experience to decrease gradually unless participants continued to receive confirmatory multisensory input. Moreover, a single instance of multisensory mismatch – a hammer striking the rubber hand but not the real hand – triggered substantial and immediate disembodiment. Together, these findings support and extend previous theoretical efforts to model body representations through basic mechanisms of multisensory integration. They further support an updating model suggesting that embodied entities fade from the body representation if they are not refreshed continuously.

scholarly journals Bliss in and Out of the Body: The (Extra)Corporeal Space Is Impervious to Social Pleasant Touch

2021 ◽  
Vol 11 (2) ◽  
pp. 225
Author(s):  
Chiara Spaccasassi ◽  
Ivana Frigione ◽  
Angelo Maravita
Keyword(s):  
Body Representation ◽  
The Body ◽  
Spatial Modulation ◽  
Impact Behavior ◽  
Space Representation ◽  
Physiological Level ◽  
Affective Touch ◽  
The Real ◽  
Healthy Humans ◽  
Skin Contact

Slow, gentle stimulation of hairy skin is generally accompanied by hedonic sensations. This phenomenon, also known as (positive) affective touch, is likely to be the basis of affiliative interactions with conspecifics by promoting inter-individual bindings. Previous studies on healthy humans have demonstrated that affective touch can remarkably impact behavior. For instance, by administering the Rubber Hand Illusion (RHI) paradigm, the embodiment of a fake hand enhances after a slow, affective touch compared to a fast, neutral touch. However, results coming from this area are not univocal. In addition, there are no clues in the existing literature on the relationship between affective touch and the space around our body. To overcome these lacks, we carried out two separate experiments where participants underwent a RHI paradigm (Experiment 1) and a Visuo-Tactile Interaction task (Experiment 2), designed to tap into body representation and peripersonal space processing, respectively. In both experiments, an affective touch (CT-optimal, 3 cm/s) and neutral touch (CT-suboptimal, 18 cm/s) were delivered by the experimenter on the dorsal side of participants’ hand through a “skin to skin” contact. In Experiment 1, we did not find any modulation of body representation—not at behavioral nor at a physiological level—by affective touch. In Experiment 2, no visuo-tactile spatial modulation emerged depending upon the pleasantness of the touch received. These null findings are interpreted in the light of the current scientific context where the real nature of affective touch is often misguided, and they offer the possibility to pave the way for understanding the real effects of affective touch on body/space representation.

scholarly journals Virtual Reality and Body Experience: a New Approach to the Treatment of Eating Disorders

1996 ◽  
Vol 2 (2) ◽  
pp. 12-31
Author(s):  
Giuseppe Riva
Keyword(s):  
Eating Disorders ◽  
Body Image ◽  
Virtual Environment ◽  
Body Representation ◽  
Normal Subjects ◽  
The Body ◽  
Behavioral Approach ◽  
Body Experience ◽  
Cognitive Representations ◽  
Immersive Virtual Environment

Eating Disorders, one of the most common pathologies of the occidental society, have long been associated with alterations in the perceptual/cognitive representations of the body. In fact, a large number of studies have highlighted the fact that the perception of one's own body and the experiences associated with it represent one of the key problems of anorexic, bulimic and obese subjects. The effects have a strong influence on therapy effects: severe body representation disturbance is predictive of treatment failure. However, the treatment of body experience problems is not well defined. Two methods are currently in use: the first is a cognitive/behavioral approach aimed at influencing patients' feelings of dissatisfaction; the second is a visual/motorial approach with the aim of influencing the level of bodily awareness. The Virtual Environment for Body Image Modification (VEBIM), a set of tasks aimed at treating body image, tries to integrate these two therapeutic approaches within an immersive virtual environment. This choice not only makes it possible to intervene simultaneously on all of the forms of bodily representations, but it also uses the psycho-physiological effectsprovoked on the body by the virtual experience for therapeutic purposes. This paper describes the VEBIM theoretical approach and its characteristics. It also presents a study on a preliminary sample (60 normal subjects) to test the efficacy of this approach.

scholarly journals Decreased motor cortex excitability mirrors own hand disembodiment during the rubber hand illusion

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Francesco della Gatta ◽  
Francesca Garbarini ◽  
Guglielmo Puglisi ◽  
Antonella Leonetti ◽  
Annamaria Berti ◽  
...  
Keyword(s):  
Motor Evoked Potentials ◽  
The Body ◽  
Rubber Hand Illusion ◽  
Body Ownership ◽  
Rubber Hand ◽  
Significant Drop ◽  
Theoretical Understanding ◽  
The Real ◽  
Motor Cortex Excitability ◽  
Real Hand

During the rubber hand illusion (RHI), subjects experience an artificial hand as part of their own body, while the real hand is subject to a sort of 'disembodiment'. Can this altered belief about the body also affect physiological mechanisms involved in body-ownership, such as motor control? Here we ask whether the excitability of the motor pathways to the real (disembodied) hand are affected by the illusion. Our results show that the amplitude of the motor-evoked potentials recorded from the real hand is significantly reduced, with respect to baseline, when subjects in the synchronous (but not in the asynchronous) condition experience the fake hand as their own. This finding contributes to the theoretical understanding of the relationship between body-ownership and motor system, and provides the first physiological evidence that a significant drop in motor excitability in M1 hand circuits accompanies the disembodiment of the real hand during the RHI experience.

Functional networks for peripersonal space coding and prediction of impact to the body

2021 ◽  
pp. 61-80
Author(s):  
Justine Cléry ◽  
Suliann Ben Hamed
Keyword(s):  
Functional Role ◽  
Body Representation ◽  
Peripersonal Space ◽  
The Body ◽  
Functional Networks ◽  
Functional Perspective ◽  
Internal States ◽  
Definition Of ◽  
Safety Boundary ◽  
Space Coding

Peripersonal space is defined as the space surrounding the body, which we can interact with and act upon. It has been hypothesized to play a key functional role in body representation and in the definition of a safety boundary around the body. More recently, growing evidence suggests that this space is dynamically resized both as a function of internal states such as anxiety or as a function of external contingencies such as social interactions or goal-directed actions. In the following review, we will review seminal and recent work in both human and non-human primates, describing the functional cortical networks involved in the coding of body margin (the skin), peripersonal space (around the body) and far space (away from the body), and we will describe how these networks are recruited during the prediction of an impact to the body (near the skin). We will propose a functional perspective to recent evidence for multiple behaviourally dissociable peripersonal spaces, and discuss the putative neuronal and network mechanisms that could account for the observed dynamic resizing of peripersonal space.

Can I Consider the Pong Racket as a Part of My Body?

2012 ◽  
Vol 3 (2) ◽  
pp. 58-63 ◽  
Author(s):  
Stefano Di Tore ◽  
Paola Aiello ◽  
Pio Alfredo Di Tore ◽  
Maurizio Sibilio
Keyword(s):  
Motor Control ◽  
Virtual Environment ◽  
Mixed Reality ◽  
Building Blocks ◽  
Theoretical Framework ◽  
The Body ◽  
Body Perception ◽  
The Real ◽  
Overall Design ◽  
Real Environment

Up to which point can people consider as part of their body the Pong racket, or an avatar on the screen, on which do people exert direct motor control as well? When individuals move in a virtual environment, do the proprioceptors convey information about the location of which body? In which environment? How will the information contaminate each other? How does the temperature felt on the real environment influence the interaction in the virtual environment? This paper is not intended to answer these questions, it is rather intended to raise fundamental questions of perception and phenomenology in a digital context in which bodies “are not born; they are made” (Haraway, 1991). The work should act as a positio quaestionis, with the aim of affirming the urgent need for a necessarily interdisciplinary reflection on the overall design of the body - perception - cognition - technology perimeter; it also identifies in the Berthoz simplexity and Ginzburg evidential paradigms, and in the Hansen concept of mixed reality, the building blocks of a theoretical framework aimed to the solution of these questions.

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