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Coppi S, Jensen KB, Ehrsson HH. Eliciting the rubber hand illusion by the activation of nociceptive C and Aδ fibers. Pain 2024:00006396-990000000-00611. [PMID: 38787634 DOI: 10.1097/j.pain.0000000000003245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 02/12/2024] [Indexed: 05/26/2024]
Abstract
ABSTRACT The coherent perceptual experience of one's own body depends on the processing and integration of signals from multiple sensory modalities, including vision, touch, and proprioception. Although nociception provides critical information about damage to the tissues of one's body, little is known about how nociception contributes to own-body perception. A classic experimental approach to investigate the perceptual and neural mechanisms involved in the multisensory experience of one's own body is the rubber hand illusion (RHI). During the RHI, people experience a rubber hand as part of their own body (sense of body ownership) caused by synchronized stroking of the rubber hand in the participant's view and the hidden participant's real hand. We examined whether the RHI can be elicited by visual and "pure" nociceptive stimulation, ie, without tactile costimulation, and if so, whether it follows the basic perceptual rules of the illusion. In 6 separate experiments involving a total of 180 healthy participants, we used a Nd:YAP laser stimulator to specifically target C and Aδ fibers in the skin and compared the illusion condition (congruent visuonociceptive stimulation) to control conditions of incongruent visuonociceptive, incongruent visuoproprioceptive, and no nociceptive stimulation. The illusion was quantified through direct (questionnaire) and indirect (proprioceptive drift) behavioral measures. We found that a nociceptive rubber hand illusion (N-RHI) could be elicited and that depended on the spatiotemporal congruence of visuonociceptive signals, consistent with basic principles of multisensory integration. Our results suggest that nociceptive information shapes multisensory bodily awareness and contributes to the sense of body ownership.
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Affiliation(s)
| | - Karin B Jensen
- Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
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2
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O'Kane SH, Chancel M, Ehrsson HH. Hierarchical and dynamic relationships between body part ownership and full-body ownership. Cognition 2024; 246:105697. [PMID: 38364444 DOI: 10.1016/j.cognition.2023.105697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 12/12/2023] [Accepted: 12/13/2023] [Indexed: 02/18/2024]
Abstract
What is the relationship between experiencing individual body parts and the whole body as one's own? We theorised that body part ownership is driven primarily by the perceptual binding of visual and somatosensory signals from specific body parts, whereas full-body ownership depends on a more global binding process based on multisensory information from several body segments. To examine this hypothesis, we used a bodily illusion and asked participants to rate illusory changes in ownership over five different parts of a mannequin's body and the mannequin as a whole, while we manipulated the synchrony or asynchrony of visual and tactile stimuli delivered to three different body parts. We found that body part ownership was driven primarily by local visuotactile synchrony and could be experienced relatively independently of full-body ownership. Full-body ownership depended on the number of synchronously stimulated parts in a nonlinear manner, with the strongest full-body ownership illusion occurring when all parts received synchronous stimulation. Additionally, full-body ownership influenced body part ownership for nonstimulated body parts, and skin conductance responses provided physiological evidence supporting an interaction between body part and full-body ownership. We conclude that body part and full-body ownership correspond to different processes and propose a hierarchical probabilistic model to explain the relationship between part and whole in the context of multisensory awareness of one's own body.
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Affiliation(s)
- Sophie H O'Kane
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
| | - Marie Chancel
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden; Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, LPNC, 38000 Grenoble, France
| | - H Henrik Ehrsson
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
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Sun Y, Zhu R, Hommel B, Ma K. Social exclusion in a virtual Cyberball game reduces the virtual hand illusion. Psychon Bull Rev 2024:10.3758/s13423-024-02456-w. [PMID: 38565842 DOI: 10.3758/s13423-024-02456-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/08/2024] [Indexed: 04/04/2024]
Abstract
Sense of ownership and agency are two important aspects of the minimal self, but how self-perception is affected by social conditions remains unclear. Here, we studied how social inclusion or exclusion of participants in the course of a virtual Cyberball game would affect explicit judgments and implicit measures of ownership and agency (proprioceptive drift, skin conductance responses, and intentional binding, respectively) in a virtual hand illusion paradigm, in which a virtual hand moved in or out of sync with the participants' own hand. Results show that synchrony affected all four measures. More importantly, this effect interacted with social inclusion/exclusion in the Cyberball game for both ownership and agency measure, showing that social exclusion reduces perceived agency and ownership.
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Affiliation(s)
- Yingbing Sun
- Key Laboratory of Personality and Cognition, Faculty of Psychological Science, Southwest University, Beibei, Chongqing, China
| | - Ruiyu Zhu
- Key Laboratory of Personality and Cognition, Faculty of Psychological Science, Southwest University, Beibei, Chongqing, China
| | - Bernhard Hommel
- Department of Psychology, Shandong Normal University, Jinan, China.
- Faculty of Psychology & University Neuropsychology Center, Faculty of Medicine, Cognitive Neurophysiology, TU Dresden, Dresden, Germany.
| | - Ke Ma
- Key Laboratory of Personality and Cognition, Faculty of Psychological Science, Southwest University, Beibei, Chongqing, China.
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Lanfranco RC, Chancel M, Ehrsson HH. Texture congruence modulates perceptual bias but not sensitivity to visuotactile stimulation during the rubber hand illusion. COGNITIVE, AFFECTIVE & BEHAVIORAL NEUROSCIENCE 2024; 24:100-110. [PMID: 38263367 PMCID: PMC10827897 DOI: 10.3758/s13415-024-01155-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 01/02/2024] [Indexed: 01/25/2024]
Abstract
The sense of body ownership is the feeling that one's body belongs to oneself. To study body ownership, researchers use bodily illusions, such as the rubber hand illusion (RHI), which involves experiencing a visible rubber hand as part of one's body when the rubber hand is stroked simultaneously with the hidden real hand. The RHI is based on a combination of vision, touch, and proprioceptive information following the principles of multisensory integration. It has been posited that texture incongruence between rubber hand and real hand weakens the RHI, but the underlying mechanisms remain poorly understood. To investigate this, we recently developed a novel psychophysical RHI paradigm. Based on fitting psychometric functions, we discovered the RHI resulted in shifts in the point of subjective equality when the rubber hand and the real hand were stroked with matching materials. We analysed these datasets further by using signal detection theory analysis, which distinguishes between the participants' sensitivity to visuotactile stimulation and the associated perceptual bias. We found that texture incongruence influences the RHI's perceptual bias but not its sensitivity to visuotactile stimulation. We observed that the texture congruence bias effect was the strongest in shorter visuotactile asynchronies (50-100 ms) and weaker in longer asynchronies (200 ms). These results suggest texture-related perceptual bias is most prominent when the illusion's sensitivity is at its lowest. Our findings shed light on the intricate interactions between top-down and bottom-up processes in body ownership, the links between body ownership and multisensory integration, and the impact of texture congruence on the RHI.
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Affiliation(s)
- Renzo C Lanfranco
- Department of Neuroscience, Karolinska Institutet, Solnavägen 9, 171 65, Stockholm, Sweden.
| | - Marie Chancel
- Department of Neuroscience, Karolinska Institutet, Solnavägen 9, 171 65, Stockholm, Sweden
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, LPNC, 38000, Grenoble, France
| | - H Henrik Ehrsson
- Department of Neuroscience, Karolinska Institutet, Solnavägen 9, 171 65, Stockholm, Sweden.
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Zhao Y, Lu E, Zeng Y. Brain-inspired bodily self-perception model for robot rubber hand illusion. PATTERNS (NEW YORK, N.Y.) 2023; 4:100888. [PMID: 38106608 PMCID: PMC10724368 DOI: 10.1016/j.patter.2023.100888] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 08/21/2023] [Accepted: 11/07/2023] [Indexed: 12/19/2023]
Abstract
The core of bodily self-consciousness involves perceiving ownership of one's body. A central question is how body illusions like the rubber hand illusion (RHI) occur. Existing theoretical models still lack satisfying computational explanations from connectionist perspectives, especially for how the brain encodes body perception and generates illusions from neuronal interactions. Moreover, the integration of disability experiments is also neglected. Here, we integrate biological findings of bodily self-consciousness to propose a brain-inspired bodily self-perception model by which perceptions of bodily self are autonomously constructed without any supervision signals. We successfully validated the model with six RHI experiments and a disability experiment on an iCub humanoid robot and simulated environments. The results show that our model can not only well-replicate the behavioral and neural data of monkeys in biological experiments but also reasonably explain the causes and results of RHI at the neuronal level, thus contributing to the revelation of mechanisms underlying RHI.
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Affiliation(s)
- Yuxuan Zhao
- Brain-inspired Cognitive Intelligence Lab, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China
| | - Enmeng Lu
- Brain-inspired Cognitive Intelligence Lab, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China
| | - Yi Zeng
- Brain-inspired Cognitive Intelligence Lab, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China
- Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
- School of Future Technology, University of Chinese Academy of Sciences, Beijing 100049, China
- School of Artificial Intelligence, University of Chinese Academy of Sciences, Beijing 100049, China
- Center for Long-term Artificial Intelligence, Beijing, China
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Yamagata T, Ichikawa K, Mizutori S, Haruki Y, Ogawa K. Revisiting the relationship between illusory hand ownership induced by visuotactile synchrony and cardiac interoceptive accuracy. Sci Rep 2023; 13:17132. [PMID: 37816882 PMCID: PMC10564882 DOI: 10.1038/s41598-023-43990-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 10/01/2023] [Indexed: 10/12/2023] Open
Abstract
Multisensory integration plays an important role in the experience of the bodily self. Recently, the relationship between exteroception and interoception has been actively debated. The first evidence was a report that the susceptibility of the sense of ownership over a fake hand (i.e., illusory hand ownership: IHO) in the typical rubber hand illusion is negatively modulated by the accuracy of the heartbeat perception (i.e., cardiac interoceptive accuracy: CIA). If reliable, this would suggest an antagonism between the exteroceptive and interoceptive cues underlying the bodily self. However, some inconsistent data have been reported, raising questions about the robustness of the initial evidence. To investigate this robustness, we estimated the extent of the modulatory effect of CIA on IHO susceptibility by applying Bayesian hierarchical modeling to two independent datasets. Overall, our results did not support that IHO susceptibility is modulated by CIA. The present estimates with high uncertainty cannot exclude the hypothesis that the relationship between IHO susceptibility and CIA is so weak as to be negligible. Further studies with larger sample sizes are needed to reach a conclusion about the extent of the modulatory effect. These findings highlight the lack of robustness of key evidence supporting the "antagonism hypothesis".
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Affiliation(s)
- Toyoki Yamagata
- Department of Psychology, Hokkaido University, Kita 10, Nishi 7, Kita-Ku, Sapporo, 060-0810, Japan.
| | - Kaito Ichikawa
- Department of Psychology, Hokkaido University, Kita 10, Nishi 7, Kita-Ku, Sapporo, 060-0810, Japan
| | - Shogo Mizutori
- Department of Behavioral Science, Hokkaido University, Hokkaido University, Kita 10, Nishi 7, Kita-Ku, Sapporo, 060-0810, Japan
| | - Yusuke Haruki
- Department of Psychology, Hokkaido University, Kita 10, Nishi 7, Kita-Ku, Sapporo, 060-0810, Japan
| | - Kenji Ogawa
- Department of Psychology, Hokkaido University, Kita 10, Nishi 7, Kita-Ku, Sapporo, 060-0810, Japan.
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Reader AT, Coppi S, Trifonova VS, Ehrsson HH. No reduction in motor-evoked potential amplitude during the rubber hand illusion. Brain Behav 2023; 13:e3211. [PMID: 37548563 PMCID: PMC10570491 DOI: 10.1002/brb3.3211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 07/03/2023] [Accepted: 07/26/2023] [Indexed: 08/08/2023] Open
Abstract
INTRODUCTION In the rubber hand illusion (RHI), touches are applied to a fake hand at the same time as touches are applied to a participant's real hand that is hidden in a congruent position. Synchronous (but not asynchronous) tactile stimulation of the two hands may induce the sensation that the fake hand is the participant's own. As such, the illusion is commonly used to examine the sense of body ownership. Some studies indicate that in addition to the subjective experience of limb ownership reported by participants, the RHI can also reduce corticospinal excitability (e.g., as reflected in motor-evoked potential [MEP] amplitude) and alter parietal-motor cortical connectivity in passive participants. These findings have been taken to support a link between motor cortical processing and the subjective experience of body ownership. METHODS In this study, we tried to replicate the reduction in MEP amplitude associated with the RHI and uncover the components of the illusion that might explain these changes. As such, we used single-pulse transcranial magnetic stimulation to probe the excitability of the corticospinal motor system as participants experienced the RHI. RESULTS Despite participants reporting the presence of the illusion and showing shifts in perceived real hand position towards the fake limb supporting its elicitation, we did not observe any associated reduction in MEP amplitude. CONCLUSION We conclude that a reduction in MEP amplitude is not a reliable outcome of the RHI and argue that if such effects do occur, they are unlikely to be large or functionally relevant.
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Affiliation(s)
- Arran T. Reader
- Department of PsychologyFaculty of Natural SciencesUniversity of StirlingStirlingUK
- Department of NeuroscienceKarolinska InstitutetStockholmSweden
| | - Sara Coppi
- Department of NeuroscienceKarolinska InstitutetStockholmSweden
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Pilacinski A, Metzler M, Klaes C. Phantom touch illusion, an unexpected phenomenological effect of tactile gating in the absence of tactile stimulation. Sci Rep 2023; 13:15453. [PMID: 37723256 PMCID: PMC10507094 DOI: 10.1038/s41598-023-42683-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 09/13/2023] [Indexed: 09/20/2023] Open
Abstract
We report the presence of a tingling sensation perceived during self-touch without physical stimulation. We used immersive virtual reality scenarios in which subjects touched their body using a virtual object. This touch resulted in a tingling sensation corresponding to the location touched on the virtual body. We called it "phantom touch illusion" (PTI). Interestingly, the illusion was also reported when subjects touched invisible (inferred) parts of their limb. We reason that this PTI results from tactile gating process during self-touch if there is no tactile input to supress. The reported PTI when touching invisible body parts indicates that tactile gating is not exclusively based on vision, but rather on multi-sensory, top-down input involving body schema. This supplementary finding shows that representations of one's own body are defined top-down, beyond the available sensory information.
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Affiliation(s)
- Artur Pilacinski
- Chair for Neurotechnology, Ruhr-University Bochum, Bochum, Germany.
| | - Marita Metzler
- Chair for Neurotechnology, Ruhr-University Bochum, Bochum, Germany
| | - Christian Klaes
- Chair for Neurotechnology, Ruhr-University Bochum, Bochum, Germany
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Santos D, Agostinho M, Treister R, Canaipa R. Correlations between within-subject variability of pain intensity reports and rubber hand illusion proprioceptive drift. Neurosci Lett 2023; 810:137319. [PMID: 37276916 DOI: 10.1016/j.neulet.2023.137319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Revised: 05/29/2023] [Accepted: 05/31/2023] [Indexed: 06/07/2023]
Abstract
INTRODUCTION Consistent with the Bayesian brain hypothesis, the within-subject variability of pain intensity reports as captured with the Focused Analgesia Selection Test (FAST) might be a surrogate measure of the certainty in ascending noxious signals. The outcomes of a non-pain-related task, the rubber hand illusion, were hypothesized to reflect the same construct. This study aimed to explore whether within-subject differences in variability of pain intensity reports and the outcomes of the rubber hand illusion might be related. METHODS Nonclinical participants underwent the classic rubber hand illusion under synchronous (experimental) and asynchronous (control) conditions. Two outcomes were assessed: proprioceptive drift and feeling of ownership. Thereafter, participants underwent the FAST to assess the within-subject variability of pain reports in response to heat stimuli. Intraclass correlation (ICC) and the correlation coefficient (R2) were the main outcomes. Spearman's correlations were used to assess associations between the outcomes of the 2 tasks. RESULTS Thirty-six volunteers completed the study. Both FAST outcomes-ICC (Spearman's r = 0.355, p = 0.033) and R2 (Spearman's r = 0.349, p = 0.037)-were positively correlated with proprioceptive drift in the synchronous but not asynchronous conditions (p > 0.05). The subjective feeling of ownership and FAST outcomes did not correlate (p > 0.05). CONCLUSIONS The associations between the 2 tasks' outcomes imply that both tasks at least partly assess similar constructs. Current knowledge suggests that this construct represents the person's certainty in perceiving ascending sensory signals, or, in Bayesian terminology, the certainty of the likelihood.
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Affiliation(s)
- Duarte Santos
- Institute of Health Sciences, Universidade Católica Portuguesa, Lisbon, Portugal
| | - Mariana Agostinho
- CIIS, Centre for Interdisciplinary Health Research, Institute of Health Sciences, Universidade Católica Portuguesa, Lisbon, Portugal; The Cheryl Spencer Department of Nursing, Faculty of Social Welfare and Health Sciences, University of Haifa, Haifa, Israel
| | - Roi Treister
- The Cheryl Spencer Department of Nursing, Faculty of Social Welfare and Health Sciences, University of Haifa, Haifa, Israel
| | - Rita Canaipa
- CIIS, Centre for Interdisciplinary Health Research, Institute of Health Sciences, Universidade Católica Portuguesa, Lisbon, Portugal.
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Özkan E, Özler C, Akar K, Youssef H, Özmen K, Şen ZD, Vural A, Gürsoy-Özdemir Y. Individual-based predominance of visual input in multisensorial integration for balance is correlated with proprioceptive drift in rubber hand illusion. Sci Rep 2023; 13:11905. [PMID: 37488214 PMCID: PMC10366093 DOI: 10.1038/s41598-023-39253-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 07/22/2023] [Indexed: 07/26/2023] Open
Abstract
Rubber hand illusion (RHI) is a traditional task that examines multisensory integration. The visual capture of tactile stimulus given to the seen rubber hand was considered to predominate the sensory processing and interfere with the bottom-up proprioceptive and tactile inputs received from the unseen real hand that results in mislocalization of participants hand towards rubber hand, namely proprioceptive drift (PD). Another task that requires multisensorial integration and shows a predominance of visual input is the maintenance of body posture. However, if the predominance of visual input in one task is generalizable to another task is yet to be elucidated. We aimed to examine if individual dependency on visual inputs in multisensorial integration in balance correlated with PD in RHI. Twenty healthy participants were recruited for the study and completed the RHI task. The contribution of visual inputs to the static body balance was measured with the instrumented clinical test of sensory interaction for balance and indexed with Romberg Quotient (RQ). We found a moderate positive correlation between PD and RQ. Individuals with more dependence on visual information in maintaining body posture had higher PD in RHI. Our results indicate that there can be an individual-based dependence on particular domains of sensory input preserved during different tasks of multisensorial integration. Future studies must clarify whether this tendency relates to certain physical or physiological traits.
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Affiliation(s)
- Esra Özkan
- Koç University Research Center for Translational Medicine, Koç University Hospital, Zeytinburnu, 34010, Istanbul, Turkey.
- Department of Neurology, School of Medicine, Koç University, Istanbul, Turkey.
| | - Ceyda Özler
- Koç University Research Center for Translational Medicine, Koç University Hospital, Zeytinburnu, 34010, Istanbul, Turkey
| | - Kardelen Akar
- Koç University Research Center for Translational Medicine, Koç University Hospital, Zeytinburnu, 34010, Istanbul, Turkey
| | - Hussein Youssef
- Koç University Research Center for Translational Medicine, Koç University Hospital, Zeytinburnu, 34010, Istanbul, Turkey
| | - Kaan Özmen
- Koç University Research Center for Translational Medicine, Koç University Hospital, Zeytinburnu, 34010, Istanbul, Turkey
| | - Zümrüt Duygu Şen
- Department of Psychiatry and Psychotherapy, Jena University Hospital, Jena, Germany
- Center for Intervention and Research on Adaptive and Maladaptive Brain Circuits Underlying Mental Health, DZP, Jena, Germany
- Clinical Affective Neuroimaging Laboratory (CANLAB), Magdeburg, Germany
- Department of Psychiatry and Psychotherapy, University Tübingen, Tübingen, Germany
| | - Atay Vural
- Koç University Research Center for Translational Medicine, Koç University Hospital, Zeytinburnu, 34010, Istanbul, Turkey
- Department of Neurology, School of Medicine, Koç University, Istanbul, Turkey
| | - Yasemin Gürsoy-Özdemir
- Koç University Research Center for Translational Medicine, Koç University Hospital, Zeytinburnu, 34010, Istanbul, Turkey
- Department of Neurology, School of Medicine, Koç University, Istanbul, Turkey
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11
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Finotti G, Garofalo S, Costantini M, Proffitt DR. Temporal dynamics of the Rubber Hand Illusion. Sci Rep 2023; 13:7526. [PMID: 37160924 PMCID: PMC10170134 DOI: 10.1038/s41598-023-33747-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 04/18/2023] [Indexed: 05/11/2023] Open
Abstract
It is widely accepted that the representation of the body is not fixed and immutable, but rather flexible and constantly updated based on a continuous stream of multisensory information. This mechanism can be very useful to adapt to several situations, but it would not be adaptive if the body representation was too malleable or if it wasn't capable of restoring its integrity after a transient modification. Here we used the Rubber Hand Illusion (RHI) to investigate how quickly the body representation can be modified. Previous studies have investigated the timing of the onset and offset of the illusion, however, they did not assess a fine temporal resolution. Here, we used a potentiometer to record a moment-by-moment rating of the feeling of owning the RH for two minutes during the visuo-tactile stimulation and two minutes following the stimulation. Our results suggest that the feeling of Ownership is already established during the first 19 s of stimulation then it continues to grow, but at a much slower pace. The feeling of Ownership disappears within 66 s from the end of the stimulation. This work sheds new light on the temporal dynamics of the RHI and the malleability of the body self-consciousness.
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Affiliation(s)
- Gianluca Finotti
- Department of Psychology, University of Virginia, Charlottesville, Virginia, USA.
- Center for Studies and Research in Cognitive Neuroscience, Department of Psychology, University of Bologna, Via Rasi e Spinelli 176, 47521, Cesena, FC, Italy.
| | - Sara Garofalo
- Center for Studies and Research in Cognitive Neuroscience, Department of Psychology, University of Bologna, Via Rasi e Spinelli 176, 47521, Cesena, FC, Italy
| | - Marcello Costantini
- Department of Psychological, Health and Territorial Sciences, University G. d'Annunzio, Chieti-Pescara, Italy
| | - Dennis R Proffitt
- Department of Psychology, University of Virginia, Charlottesville, Virginia, USA
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12
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Berger CC, Coppi S, Ehrsson HH. Synchronous motor imagery and visual feedback of finger movement elicit the moving rubber hand illusion, at least in illusion-susceptible individuals. Exp Brain Res 2023; 241:1021-1039. [PMID: 36928694 PMCID: PMC10081980 DOI: 10.1007/s00221-023-06586-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 02/26/2023] [Indexed: 03/18/2023]
Abstract
Recent evidence suggests that imagined auditory and visual sensory stimuli can be integrated with real sensory information from a different sensory modality to change the perception of external events via cross-modal multisensory integration mechanisms. Here, we explored whether imagined voluntary movements can integrate visual and proprioceptive cues to change how we perceive our own limbs in space. Participants viewed a robotic hand wearing a glove repetitively moving its right index finger up and down at a frequency of 1 Hz, while they imagined executing the corresponding movements synchronously or asynchronously (kinesthetic-motor imagery); electromyography (EMG) from the participants' right index flexor muscle confirmed that the participants kept their hand relaxed while imagining the movements. The questionnaire results revealed that the synchronously imagined movements elicited illusory ownership and a sense of agency over the moving robotic hand-the moving rubber hand illusion-compared with asynchronously imagined movements; individuals who affirmed experiencing the illusion with real synchronous movement also did so with synchronous imagined movements. The results from a proprioceptive drift task further demonstrated a shift in the perceived location of the participants' real hand toward the robotic hand in the synchronous versus the asynchronous motor imagery condition. These results suggest that kinesthetic motor imagery can be used to replace veridical congruent somatosensory feedback from a moving finger in the moving rubber hand illusion to trigger illusory body ownership and agency, but only if the temporal congruence rule of the illusion is obeyed. This observation extends previous studies on the integration of mental imagery and sensory perception to the case of multisensory bodily awareness, which has potentially important implications for research into embodiment of brain-computer interface controlled robotic prostheses and computer-generated limbs in virtual reality.
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Affiliation(s)
- Christopher C Berger
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
- Division of Biology and Biological Engineering/Computation and Neural Systems, California Institute of Technology, Pasadena, CA, USA
| | - Sara Coppi
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
| | - H Henrik Ehrsson
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
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13
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Nishiyama Y, Yamashita C, Nomura S. An illusion of disownership over one's own limb is associated with pain perception. Sci Rep 2023; 13:2801. [PMID: 36859438 PMCID: PMC9977932 DOI: 10.1038/s41598-023-29993-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 02/14/2023] [Indexed: 03/03/2023] Open
Abstract
Viewing one's body and even a fake/virtual body experienced as one's own has been suggested to modulate pain perception. However, what happens to pain perception when one's own body part is felt as not belonging to one? We designed a paradigm to induce an illusory feeling of disownership regarding one's limb, investigating whether the feeling affects pain threshold. Participants observed right-side images of their bodies from a third-person perspective via a head-mounted display in real-time. Following instructions, they moved their left hand while keeping their left elbow behind the upper body, so that the connection of their arm to the torso was not visible (test condition), or in front of it, so they could see the arm being part of them (control condition). Then, pain threshold was tested with a thermal stimulator. We found a significantly higher strength of disownership in the test condition than in the control condition. While there was no pain modulation within and between conditions, disownership ratings negatively correlated with pain-threshold changes, where the participants reporting explicit disownership showed lower pain-threshold changes than the others. The finding suggests that while multisensory disintegration had no modulatory effect, the individual sense of disownership was associated with pain perception.
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Affiliation(s)
- Yuta Nishiyama
- Department of Information and Management Systems Engineering, Nagaoka University of Technology, Niigata, Japan.
| | - Chihiro Yamashita
- grid.260427.50000 0001 0671 2234Department of Information and Management Systems Engineering, Nagaoka University of Technology, Niigata, Japan
| | - Shusaku Nomura
- grid.260427.50000 0001 0671 2234Department of Information and Management Systems Engineering, Nagaoka University of Technology, Niigata, Japan
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Comparative effects of hypnotic suggestion and imagery instruction on bodily awareness. Conscious Cogn 2023; 108:103473. [PMID: 36706563 DOI: 10.1016/j.concog.2023.103473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 10/31/2022] [Accepted: 01/12/2023] [Indexed: 01/26/2023]
Abstract
Bodily awareness is informed by both sensory data and prior knowledge. Although misleading sensory signals have been repeatedly shown to affect bodily awareness, only scant attention has been given to the influence of cognitive variables. Hypnotic suggestion has recently been shown to impact visuospatial and sensorimotor representations of body-part size although the mechanisms subserving this effect are yet to be identified. Mental imagery might play a causal or facilitative role in this effect, as it has been shown to influence body awareness in previous studies. Nonetheless, current views ascribe only an epiphenomenal role to imagery in the implementation of hypnotic suggestions. This study compared the effects of hypnotic suggestion and imagery instruction for influencing the visuospatial and sensorimotor aspects of body-size representation. Both experimental manipulations produced significant increases (elongation) in both representations compared to baseline, although the effects were larger in the hypnotic suggestion condition. The effects of both manipulations were highly correlated across participants, suggesting overlapping mechanisms. Self-reports suggested that the use of voluntary imagery did not significantly contribute to the efficacy of either manipulation. Rather, top-down effects on body representations seem to be partly driven by response expectancies, spontaneous imagery, and hypnotic suggestibility in both conditions. These results are in line with current theories of suggestion and raise fundamental questions regarding the mechanisms driving the influence of cognition on body representations.
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Segil JL, Roldan LM, Graczyk EL. Measuring embodiment: A review of methods for prosthetic devices. Front Neurorobot 2022; 16:902162. [PMID: 36590084 PMCID: PMC9797051 DOI: 10.3389/fnbot.2022.902162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 10/25/2022] [Indexed: 12/23/2022] Open
Abstract
The development of neural interfaces to provide improved control and somatosensory feedback from prosthetic limbs has initiated a new ability to probe the various dimensions of embodiment. Scientists in the field of neuroprosthetics require dependable measures of ownership, body representation, and agency to quantify the sense of embodiment felt by patients for their prosthetic limbs. These measures are critical to perform generalizable experiments and compare the utility of the new technologies being developed. Here, we review outcome measures used in the literature to evaluate the senses of ownership, body-representation, and agency. We categorize these existing measures based on the fundamental psychometric property measured and whether it is a behavioral or physiological measure. We present arguments for the efficacy and pitfalls of each measure to guide better experimental designs and future outcome measure development. The purpose of this review is to aid prosthesis researchers and technology developers in understanding the concept of embodiment and selecting metrics to assess embodiment in their research. Advances in the ability to measure the embodiment of prosthetic devices have far-reaching implications in the improvement of prosthetic limbs as well as promoting a broader understanding of ourselves as embodied agents.
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Affiliation(s)
- Jacob L. Segil
- Department of Mechanical Engineering, University of Colorado, Boulder, CO, United States
- Rocky Mountain Regional VA Medical Center, Aurora, CO, United States
| | - Leah Marie Roldan
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States
- Louis Stokes Cleveland VA Medical Center, Cleveland, OH, United States
| | - Emily L. Graczyk
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States
- Louis Stokes Cleveland VA Medical Center, Cleveland, OH, United States
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