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Augière T, Metral M, Simoneau M, Mercier C. Preserved tactile distance estimation despite body representation distortions in individuals with fibromyalgia. FRONTIERS IN PAIN RESEARCH 2024; 5:1414927. [PMID: 39119526 PMCID: PMC11306202 DOI: 10.3389/fpain.2024.1414927] [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: 04/09/2024] [Accepted: 07/09/2024] [Indexed: 08/10/2024] Open
Abstract
Our mental representation of our body depends on integrating various sensory modalities, such as tactile information. In tactile distance estimation (TDE) tasks, participants must estimate the distance between two tactile tips applied to their skin. This measure of tactile perception has been linked to body representation assessments. Studies in individuals with fibromyalgia (FM), a chronic widespread pain syndrome, suggest the presence of body representation distortions and tactile alterations, but TDE has never been examined in this population. Twenty participants with FM and 24 pain-free controls performed a TDE task on three Body regions (upper limb, trunk, lower limb), in which they manually estimated the interstimuli distance on a tablet. TDE error, the absolute difference between the estimation and the interstimuli distance, was not different between the Groups, on any Body region. Drawings of their body as they felt it revealed clear and frequent distortions of body representation in the group with FM, compared to negligible perturbations in controls. This contrast between distorted body drawings and unaltered TDE suggests a preserved integration of tactile information but an altered integration of this information with other sensory modalities to generate a precise and accurate body representation. Future research should investigate the relative contribution of each sensory information and prior knowledge about the body in body representation in individuals with FM to shed light on the observed distortions.
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Affiliation(s)
- Tania Augière
- Center for Interdisciplinary Research in Rehabilitation and Social Integration (Cirris), Quebec, QC, Canada
- School of Rehabilitation Sciences, Faculty of Medicine, Laval University, Quebec, QC, Canada
| | - Morgane Metral
- Univ. Savoie Mont Blanc, Univ. Grenoble Alpes, LIP/PC2S, Grenoble, France
| | - Martin Simoneau
- Center for Interdisciplinary Research in Rehabilitation and Social Integration (Cirris), Quebec, QC, Canada
- Department of Kinesiology, Faculty of Medicine, Laval University, Quebec, QC, Canada
| | - Catherine Mercier
- Center for Interdisciplinary Research in Rehabilitation and Social Integration (Cirris), Quebec, QC, Canada
- School of Rehabilitation Sciences, Faculty of Medicine, Laval University, Quebec, QC, Canada
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Bellard A, Trotter PD, McGlone FL, Cazzato V. Role of medial prefrontal cortex and primary somatosensory cortex in self and other-directed vicarious social touch: a TMS study. Soc Cogn Affect Neurosci 2023; 18:nsad060. [PMID: 37837378 PMCID: PMC10640852 DOI: 10.1093/scan/nsad060] [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: 04/11/2023] [Revised: 08/11/2023] [Accepted: 10/05/2023] [Indexed: 10/16/2023] Open
Abstract
Conflicting evidence points to the contribution of several key nodes of the 'social brain' to the processing of both discriminatory and affective qualities of interpersonal touch. Whether the primary somatosensory cortex (S1) and the medial prefrontal cortex (mPFC), two brain areas vital for tactile mirroring and affective mentalizing, play a functional role in shared representations of C-tactile (CT) targeted affective touch is still a matter of debate. Here, we used offline continuous theta-burst transcranial magnetic stimulation (cTBS) to mPFC, S1 and vertex (control) prior to participants providing ratings of vicarious touch pleasantness for self and others delivered across several body sites at CT-targeted velocities. We found that S1-cTBS led to a significant increase in touch ratings to the self, with this effect being positively associated to levels of interoceptive awareness. Conversely, mPFC-cTBS reduced pleasantness ratings for touch to another person. These effects were not specific for CT-optimal (slow) stroking velocities, but rather they applied to all types of social touch. Overall, our findings challenge the causal role of the S1 and mPFC in vicarious affective touch and suggest that self- vs other-directed vicarious touch responses might crucially depend on the specific involvement of key social networks in gentle tactile interactions.
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Affiliation(s)
- Ashleigh Bellard
- School of Psychology, Faculty of Health, Liverpool John Moores University, Liverpool, UK
| | - Paula D Trotter
- School of Psychology, Faculty of Health, Liverpool John Moores University, Liverpool, UK
| | - Francis L McGlone
- Institute of Psychology, Health & Society, University of Liverpool, Liverpool, UK
| | - Valentina Cazzato
- School of Psychology, Faculty of Health, Liverpool John Moores University, Liverpool, UK
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Chazelle T, Guerraz M, Palluel-Germain R. Mirror exposure following visual body-size adaptation does not affect own body image. ROYAL SOCIETY OPEN SCIENCE 2023; 10:221589. [PMID: 37593706 PMCID: PMC10427814 DOI: 10.1098/rsos.221589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 07/24/2023] [Indexed: 08/19/2023]
Abstract
Prolonged visual exposure to large bodies produces a thinning aftereffect on subsequently seen bodies, and vice versa. This visual adaptation effect could contribute to the link between media exposure and body shape misperception. Indeed, people exposed to thin bodies in the media, who experience fattening aftereffects, may internalize the distorted image of their body they see in the mirror. This preregistered study tested this internalization hypothesis by exposing 196 young women to an obese adaptor before showing them their reflection in the mirror, or to a control condition. Then, we used a psychophysical task to measure the effects of this procedure on perceptual judgements about their own body size, relative to another body and to the control mirror exposure condition. We found moderate evidence against the hypothesized self-specific effects of mirror exposure on perceptual judgements. Our work strengthens the idea that body size adaptation affects the perception of test stimuli rather than the participants' own body image. We discuss recent studies which may provide an alternative framework to study media-related distortions of perceptual body image.
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Affiliation(s)
- Thomas Chazelle
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, LPNC, 38000 Grenoble, France
| | - Michel Guerraz
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, LPNC, 38000 Grenoble, France
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D'Amour S, Alexe D, Harris LR. Changes in the perceived size of the body following exposure to distorted self-body images. ROYAL SOCIETY OPEN SCIENCE 2022; 9:210722. [PMID: 35462776 PMCID: PMC9019518 DOI: 10.1098/rsos.210722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 03/22/2022] [Indexed: 06/14/2023]
Abstract
Inaccurate perceptions, such as under- or over-estimation of body size are often found in clinical eating disorder populations but have recently been shown also in healthy people. However, it is not yet clear how body size perception may be affected when the internal body representation is manipulated. In this study, visual adaptation was used to investigate whether exposure to distorted visual feedback alters the representation of body size and how long any such effects might last. Participants were exposed for five minutes to a distorted life-size image of themselves that was either 20% wider or 20% narrower than their normal size. Accuracy was measured using our novel psychophysical method that taps into the implicit body representation. The accuracy of the representation was assessed at 6, 12 and 18 min following exposure to adaptation. Altered visual feedback caused changes in participants' judgements of their body size: adapting to a wider body resulted in size overestimation whereas underestimations occurred after adapting to a narrower body. These distortions lasted throughout testing and did not fully return back to normal within 18 min. The results are discussed in terms of the emerging literature indicating that the internal representation of the body is dynamic and flexible.
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Affiliation(s)
- Sarah D'Amour
- Centre for Vision Research, York University, Toronto, Canada
| | - Deborah Alexe
- Centre for Vision Research, York University, Toronto, Canada
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Brooks KR, Stevenson RJ, Stephen ID. Over or Under? Mental Representations and the Paradox of Body Size Estimation. Front Psychol 2021; 12:706313. [PMID: 34413814 PMCID: PMC8369339 DOI: 10.3389/fpsyg.2021.706313] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 06/30/2021] [Indexed: 12/20/2022] Open
Affiliation(s)
- Kevin R Brooks
- Body Image & Ingestion Group (BIIG), Faculty of Medicine, Health & Human Sciences, School of Psychological Sciences, Macquarie University, Sydney, NSW, Australia.,Perception in Action Research Centre (PARC), Faculty of Medicine, Health & Human Sciences, Macquarie University, Sydney, NSW, Australia
| | - Richard J Stevenson
- Body Image & Ingestion Group (BIIG), Faculty of Medicine, Health & Human Sciences, School of Psychological Sciences, Macquarie University, Sydney, NSW, Australia.,Perception in Action Research Centre (PARC), Faculty of Medicine, Health & Human Sciences, Macquarie University, Sydney, NSW, Australia
| | - Ian D Stephen
- Body Image & Ingestion Group (BIIG), Faculty of Medicine, Health & Human Sciences, School of Psychological Sciences, Macquarie University, Sydney, NSW, Australia.,Perception in Action Research Centre (PARC), Faculty of Medicine, Health & Human Sciences, Macquarie University, Sydney, NSW, Australia
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