1
|
Coelho LA, Gonzalez CLR. Perception, action, and the body model. Neuropsychologia 2024; 196:108853. [PMID: 38490535 DOI: 10.1016/j.neuropsychologia.2024.108853] [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: 01/20/2024] [Revised: 03/02/2024] [Accepted: 03/12/2024] [Indexed: 03/17/2024]
Abstract
In 1992, Goodale and Milner proposed to study the visual system based on function, thus dissociating vision for perception (ventral stream) and vision for action (dorsal stream). This became known as the Perception and Action model (PAM). Following the PAM in the visual system, a somatosensory PAM was proposed including a body representation for perception and a separate for action. This review explores the body model of the hand and how it relates to the PAM. The body model refers to the internal representation of the body that is responsible for position sense. Previous research has shown that the representation of the hand features systematic distortions: an overestimation of hand width and an underestimation of finger length. These distortions have been reported using different paradigms, different body parts, and in various settings. Thus, body model distortions appear to be a characteristic of human body representation. If the body model of the hand is distorted, how can actions like reaching and grasping be accurate? We review evidence that body model distortions may in fact provide a functional benefit to our actions, that cortical maps in the somatosensory and motor cortices reflect these distortions, and that actions rely on a distorted body model. We argue that the body model is a product of both the ventral and dorsal somatosensory streams. Further, we suggest that the body model is an example of the inextricable link between the two streams.
Collapse
Affiliation(s)
- Lara A Coelho
- Brain in Action Laboratory, Department of Kinesiology, University of Lethbridge, AB, Canada; UVIP: Unit for Visually Impaired People, Italian Institute of Technology, Genova, Italy.
| | - Claudia L R Gonzalez
- Brain in Action Laboratory, Department of Kinesiology, University of Lethbridge, AB, Canada
| |
Collapse
|
2
|
Hidaka S, Chen N, Ishii N, Iketani R, Suzuki K, Longo MR, Wada M. No differences in implicit hand maps among different degrees of autistic traits. Autism Res 2023; 16:1750-1764. [PMID: 37409496 DOI: 10.1002/aur.2979] [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: 11/20/2022] [Accepted: 06/18/2023] [Indexed: 07/07/2023]
Abstract
People with autism spectrum disorder (ASD) or higher levels of autistic traits have atypical characteristics in sensory processing. Atypicalities have been reported for proprioceptive judgments, which are tightly related to internal bodily representations underlying position sense. However, no research has directly investigated whether self-bodily representations are different in individuals with ASD. Implicit hand maps, estimated based on participants' proprioceptive sensations without sight of their hand, are known to be distorted such that the shape is stretched along the medio-lateral hand axis even for neurotypical participants. Here, with the view of ASD as falling on a continuous distribution among the general population, we explored differences in implicit body representations along with autistic traits by focusing on relationships between autistic traits and the magnitudes of the distortions in implicit hand maps (N ~ 100). We estimated the magnitudes of distortions in implicit hand maps both for fingers and hand surfaces on the dorsal and palmar sides of the hand. Autistic traits were measured by questionnaires (Autism Spectrum [AQ] and Empathy/Systemizing [EQ-SQ] Quotients). The distortions in implicit hand maps were replicated in our experimental situations. However, there were no significant relationships between autistic traits and the magnitudes of the distortions as well as within-individual variabilities in the maps and localization performances. Consistent results were observed from comparisons between IQ-matched samples of people with and without a diagnosis of ASD. Our findings suggest that there exist perceptual and neural processes for implicit body representations underlying position sense consistent across levels of autistic traits.
Collapse
Affiliation(s)
- Souta Hidaka
- Department of Psychology, Rikkyo University, Tokyo, Japan
- Department of Psychology, Faculty of Human Sciences, Sophia University, Tokyo, Japan
| | - Na Chen
- Developmental Disorders Section, Department of Rehabilitation for Brain Functions, Research Institute of National Rehabilitation Center for Persons with Disabilities, Tokorozawa City, Japan
- The Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat Gan, Israel
| | - Naomi Ishii
- Developmental Disorders Section, Department of Rehabilitation for Brain Functions, Research Institute of National Rehabilitation Center for Persons with Disabilities, Tokorozawa City, Japan
| | - Risa Iketani
- Department of Psychology, Rikkyo University, Tokyo, Japan
| | - Kirino Suzuki
- Department of Psychology, Rikkyo University, Tokyo, Japan
| | - Matthew R Longo
- Department of Psychological Sciences, Birkbeck, University of London, London, UK
| | - Makoto Wada
- Developmental Disorders Section, Department of Rehabilitation for Brain Functions, Research Institute of National Rehabilitation Center for Persons with Disabilities, Tokorozawa City, Japan
| |
Collapse
|
3
|
Have L, Quesque F, Priot AE, Chastres V, Revol P, Delporte L, Chabanat E, Obadia N, Cotton F, Reilly KT, Rossetti Y. Feeling without localizing: exploring tactile misperception in a patient with uncommon parietal left brain damage. Front Hum Neurosci 2023; 17:1167489. [PMID: 37425290 PMCID: PMC10326386 DOI: 10.3389/fnhum.2023.1167489] [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: 02/16/2023] [Accepted: 05/10/2023] [Indexed: 07/11/2023] Open
Abstract
Introduction We report a very unique clinical presentation of a patient who complained, after a left parietal brain damage, about feeling tactile stimulations on his right upper limb without being able to localize them. Methods Using a single case study approach, we report three experiments relying on several custom-made tasks to explore the different levels of somatosensory information processing, ranging from somato-sensation to somato-representation. Results Our results showed a preserved ability to localize tactile stimuli applied on the right upper limb when using pointing responses while the ability to localize was less efficient when having to name the stimulated part (akin Numbsense). When the stimuli were applied on more distal locations (i.e., on the hand and on fingers), the number of correct responses decreased significantly independently of the modality of response. Finally, when visually presented with a stimulus delivered on the hand of an examiner in synchrony with the stimulation on the hidden hand of the patient, responses were largely influenced by the visual information available. Altogether, the convergence of these different customized tasks revealed an absence of autotopagnosia for motor responses for the right upper limb, associated with altered abilities to discriminate stimulus applied on distal and restricted/closer zones in the hand. Discussion The somato-representation of our patient seemed to significantly rely on visual information, leading to striking deficits to localize tactile stimuli when vision and somesthesic afferences are discordant. This case report offers a clinical illustration of pathological imbalance between vision and somesthesia. Implications of these troubles in somato-representation on higher cognitive level processes are discussed.
Collapse
Affiliation(s)
- Laurence Have
- CNRS, INSERM, Centre de Recherche en Neurosciences de Lyon CRNL U1028 UMR 5292, Trajectoires, F-69500, Université Claude Bernard Lyon 1, Bron, France
| | - François Quesque
- CNRS, INSERM, Centre de Recherche en Neurosciences de Lyon CRNL U1028 UMR 5292, Trajectoires, F-69500, Université Claude Bernard Lyon 1, Bron, France
| | - Anne-Emmanuelle Priot
- CNRS, INSERM, Centre de Recherche en Neurosciences de Lyon CRNL U1028 UMR 5292, Trajectoires, F-69500, Université Claude Bernard Lyon 1, Bron, France
- Institut de Recherche Biomédicale des Armées (IRBA), French Military Health Service, Brétigny-sur-Orge, France
| | - Véronique Chastres
- Institut de Recherche Biomédicale des Armées (IRBA), French Military Health Service, Brétigny-sur-Orge, France
| | - Patrice Revol
- Service de Médecine Physique et Réadaptation, Plateforme Mouvement et Handicap, Hôpital Henry Gabrielle, Hospices Civils de Lyon, Pierre-Bénite, France
| | - Ludovic Delporte
- Service de Médecine Physique et Réadaptation, Plateforme Mouvement et Handicap, Hôpital Henry Gabrielle, Hospices Civils de Lyon, Pierre-Bénite, France
| | - Eric Chabanat
- CNRS, INSERM, Centre de Recherche en Neurosciences de Lyon CRNL U1028 UMR 5292, Trajectoires, F-69500, Université Claude Bernard Lyon 1, Bron, France
| | - Nathalie Obadia
- Service de Médecine Physique et Réadaptation, Plateforme Mouvement et Handicap, Hôpital Henry Gabrielle, Hospices Civils de Lyon, Pierre-Bénite, France
| | - François Cotton
- Service de Radiologie, Hospices Civils de Lyon, Centre Hospitalier Lyon Sud, Pierre-Bénite, France
- Creatis Lab–CNRS UMR 5220–INSERM U1206 Université de Lyon, Université Lyon 1, Lyon, France
| | - Karen T. Reilly
- CNRS, INSERM, Centre de Recherche en Neurosciences de Lyon CRNL U1028 UMR 5292, Trajectoires, F-69500, Université Claude Bernard Lyon 1, Bron, France
| | - Yves Rossetti
- CNRS, INSERM, Centre de Recherche en Neurosciences de Lyon CRNL U1028 UMR 5292, Trajectoires, F-69500, Université Claude Bernard Lyon 1, Bron, France
- Service de Médecine Physique et Réadaptation, Plateforme Mouvement et Handicap, Hôpital Henry Gabrielle, Hospices Civils de Lyon, Pierre-Bénite, France
| |
Collapse
|
4
|
Implicit Body Representation of the Hand Enlarged by Repetitive Peripheral Magnetic Stimulation within the Boundary of a Real Hand. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12105250] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Deafferentation induced by local anesthesia causes a larger perceived area than the real area of the mouth, which, in the perspective of body representation, belongs to implicit body representation. In this study, we applied repetitive peripheral magnetic stimulation (rPMS) on the motor branch of the radial nerve of participants’ non-dominant-side forearm to induce extension movements of wrist and fingers. This intervention was supposed to increase proprioception to the brain and had an enlargement effect on implicit body representation of the hand in our hypothesis. A total of 39 participants were randomly allocated to the real rPMS group (n = 19) or the sham rPMS group (n = 20). Implicit representation of the hand was measured by a simplified paradigm based on the proposal of Longo and Haggard that depicted perceived locations of fingertips and metacarpophalangeal joints of participants’ occluded hand, in which they showed that implicit body representation of the hand was smaller than the real hand. We compare the main effect of real rPMS vs. sham rPMS and its interaction effect with time by setting four timepoints—before stimulation, right after stimulation, 10 min after stimulation and 20 min after stimulation—to demonstrate the possible short-lasting effect. Results showed that real rPMS had a short-lasting enlargement effect on implicit representation of the hand in general, which was significant especially on the ulnar side of fingers. What is more, the enlarged implicit body representation of the hand was still within the boundary of a real hand, which might indicate the identification role of a real body part.
Collapse
|
5
|
Longo MR. Distortion of mental body representations. Trends Cogn Sci 2022; 26:241-254. [PMID: 34952785 DOI: 10.1016/j.tics.2021.11.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Revised: 11/18/2021] [Accepted: 11/21/2021] [Indexed: 01/07/2023]
Abstract
Our body is central to our sense of self, and distorted body representations are found in several serious medical conditions. This paper reviews evidence that distortions of body representations are also common in healthy individuals, and occur in domains including tactile spatial perception, proprioception, and the conscious body image. Across domains, there is a general tendency for body width to be overestimated compared to body length. Intriguingly, distortions in both eating disorders and chronic pain appear to be exaggerations of this baseline pattern of distortions, suggesting that these conditions may relate to dysfunction of mechanisms for body perception. Distortions of body representations provide a revealing window into basic aspects of self-perception.
Collapse
Affiliation(s)
- Matthew R Longo
- Department of Psychological Sciences, Birkbeck, University of London, Malet Street, London WC1E 7HX, UK.
| |
Collapse
|
6
|
Longo MR. No evidence for sex differences in tactile distance anisotropy. Exp Brain Res 2022; 240:591-600. [PMID: 34984563 DOI: 10.1007/s00221-021-06301-7] [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: 10/11/2021] [Accepted: 12/23/2021] [Indexed: 11/30/2022]
Abstract
Perceptual illusions of the distance between two touches have been used to study mental representations of the body since E. H. Weber's classic studies in the nineteenth century. For example, on many body parts tactile distance is anisotropic, with distances aligned with body width being perceived as larger than distances aligned with body length on several skin regions. Recent work has demonstrated sex differences in other distortions of mental body representations, such as proprioceptive hand maps. Given such findings, I analysed the results of 24 experiments, conducted by myself and my colleagues, measuring tactile distance anisotropy on the hand dorsum in both women and men. The results showed clear, and highly consistent anisotropy in both women and men, with no evidence for any sex difference.
Collapse
Affiliation(s)
- Matthew R Longo
- Department of Psychological Sciences, Birkbeck, University of London, Malet Street, London, WC1E 7HX, UK.
| |
Collapse
|
7
|
Coelho LA, Gonzalez CLR. Growing into your hand: the developmental trajectory of the body model. Exp Brain Res 2021; 240:135-145. [PMID: 34654947 DOI: 10.1007/s00221-021-06241-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 10/04/2021] [Indexed: 10/20/2022]
Abstract
We rely on accurate body representations to successfully interact with the environment. As adults, we rely on many years of experience with a body that has stayed relatively the same size. Children, however, go through periods of rapid growth and whether or not their body representation matches this physical growth is unknown. To address this question, we examined the developmental trajectory of the body model of the hand. The body model is the representation of our bodies that underlies position sense. We recruited a group of children (8-16 years) and a control group of young adults (18-26 years) and asked them to complete the body model task. In this task, participants estimated the location of ten different landmarks (the tips and metacarpophalangeal joints of each of their five fingers). The position (XY location) of each estimate was tracked using an Optotrak camera. From the XY locations we derived hand width and finger length. Not surprisingly, children's physical hand width and finger length were smaller than adults but remarkably, the body model, was similar for both groups. This result indicates that children overestimate hand size and suggests that the body model is ahead of physical growth. This result contradicts the notion that body representation lags physical growth during puberty, accounting for the clumsy motor behaviour characteristic of teens. We discuss the results in relation to the different taxonomies of body representation and how an enlarged representation of the hand during childhood may influence action.
Collapse
Affiliation(s)
- Lara A Coelho
- The Brain in Action Laboratory, Department of Kinesiology, University of Lethbridge, Lethbridge, AB, T1K 3M4, Canada.
| | - Claudia L R Gonzalez
- The Brain in Action Laboratory, Department of Kinesiology, University of Lethbridge, Lethbridge, AB, T1K 3M4, Canada
| |
Collapse
|
8
|
The signing body: extensive sign language practice shapes the size of hands and face. Exp Brain Res 2021; 239:2233-2249. [PMID: 34028597 PMCID: PMC8282562 DOI: 10.1007/s00221-021-06121-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 04/21/2021] [Indexed: 11/20/2022]
Abstract
The representation of the metrics of the hands is distorted, but is susceptible to malleability due to expert dexterity (magicians) and long-term tool use (baseball players). However, it remains unclear whether modulation leads to a stable representation of the hand that is adopted in every circumstance, or whether the modulation is closely linked to the spatial context where the expertise occurs. To this aim, a group of 10 experienced Sign Language (SL) interpreters were recruited to study the selective influence of expertise and space localisation in the metric representation of hands. Experiment 1 explored differences in hands’ size representation between the SL interpreters and 10 age-matched controls in near-reaching (Condition 1) and far-reaching space (Condition 2), using the localisation task. SL interpreters presented reduced hand size in near-reaching condition, with characteristic underestimation of finger lengths, and reduced overestimation of hands and wrists widths in comparison with controls. This difference was lost in far-reaching space, confirming the effect of expertise on hand representations is closely linked to the spatial context where an action is performed. As SL interpreters are also experts in the use of their face with communication purposes, the effects of expertise in the metrics of the face were also studied (Experiment 2). SL interpreters were more accurate than controls, with overall reduction of width overestimation. Overall, expertise modifies the representation of relevant body parts in a specific and context-dependent manner. Hence, different representations of the same body part can coexist simultaneously.
Collapse
|
9
|
Ambrosini E, Gasperini G, Zajc J, Immick N, Augsten A, Rossini M, Ballarati R, Russold M, Ferrante S, Ferrigno G, Bulgheroni M, Baccinelli W, Schauer T, Wiesener C, Gfoehler M, Puchinger M, Weber M, Weber S, Pedrocchi A, Molteni F, Krakow K. A Robotic System with EMG-Triggered Functional Eletrical Stimulation for Restoring Arm Functions in Stroke Survivors. Neurorehabil Neural Repair 2021; 35:334-345. [PMID: 33655789 DOI: 10.1177/1545968321997769] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Robotic systems combined with Functional Electrical Stimulation (FES) showed promising results on upper-limb motor recovery after stroke, but adequately-sized randomized controlled trials (RCTs) are still missing. OBJECTIVE To evaluate whether arm training supported by RETRAINER, a passive exoskeleton integrated with electromyograph-triggered functional electrical stimulation, is superior to advanced conventional therapy (ACT) of equal intensity in the recovery of arm functions, dexterity, strength, activities of daily living, and quality of life after stroke. METHODS A single-blind RCT recruiting 72 patients was conducted. Patients, randomly allocated to 2 groups, were trained for 9 weeks, 3 times per week: the experimental group performed task-oriented exercises assisted by RETRAINER for 30 minutes plus ACT (60 minutes), whereas the control group performed only ACT (90 minutes). Patients were assessed before, soon after, and 1 month after the end of the intervention. Outcome measures were as follows: Action Research Arm Test (ARAT), Motricity Index, Motor Activity Log, Box and Blocks Test (BBT), Stroke Specific Quality of Life Scale (SSQoL), and Muscle Research Council. RESULTS All outcomes but SSQoL significantly improved over time in both groups (P < .001); a significant interaction effect in favor of the experimental group was found for ARAT and BBT. ARAT showed a between-group change of 11.5 points (P = .010) at the end of the intervention, which increased to 13.6 points 1 month after. Patients considered RETRAINER moderately usable (System Usability Score of 61.5 ± 22.8). CONCLUSIONS Hybrid robotic systems, allowing to perform personalized, intensive, and task-oriented training, with an enriched sensory feedback, was superior to ACT in improving arm functions and dexterity after stroke.
Collapse
Affiliation(s)
| | | | | | - Nancy Immick
- Asklepios Neurologische Klinik Falkenstein, Königstein, Germany
| | - Andreas Augsten
- Asklepios Neurologische Klinik Falkenstein, Königstein, Germany
| | - Mauro Rossini
- Villa Beretta Rehabilitation Center, Costamasnaga, Italy
| | | | | | | | | | | | | | | | | | | | | | | | | | | | - Franco Molteni
- Villa Beretta Rehabilitation Center, Costamasnaga, Italy
| | - Karsten Krakow
- Asklepios Neurologische Klinik Falkenstein, Königstein, Germany
| |
Collapse
|
10
|
Myga KA, Ambroziak KB, Tamè L, Farnè A, Longo MR. Whole-hand perceptual maps of joint location. Exp Brain Res 2021; 239:1235-1246. [PMID: 33590275 DOI: 10.1007/s00221-021-06043-6] [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: 11/01/2020] [Accepted: 01/16/2021] [Indexed: 11/24/2022]
Abstract
Hands play a fundamental role in everyday behaviour. Nevertheless, healthy adults show striking misrepresentations of their hands which have been documented by a wide range of studies addressing various aspects of body representation. For example, when asked to indicate the location within the hand of the knuckles, people place them substantially farther forward than they actually are. Previous research, however, has focused exclusively on the knuckles at the base of each finger, not considering the other knuckles in the fingers. This study, therefore, aimed to investigate conceptual knowledge of the structure of the whole hand, by investigating judgements of the location of all 14 knuckle joints in the hand. Participants localised each of the 14 knuckles of their own hand (Experiment 1) or of the experimenter's hand (Experiment 2) on a hand silhouette. We measured whether there are systematic localisation biases. The results showed highly similar pattern of mislocalisation for the knuckles of one's own hand and those of another person's hand, suggesting that people share an abstract conceptual knowledge about the hand structure. In line with previous reports, we showed that the metacarpophalangeal joints at the base of the fingers are judged as substantially father forward in the hand than they actually are. Moreover, for the first time we showed a gradient of this bias, with progressive reduction of distal bias from more proximal to more distal joints. In sum, people think their finger segments are roughly the same, and that their fingers are shorter than they are.
Collapse
Affiliation(s)
- Kasia A Myga
- Department of Psychological Sciences, University of London, Malet Street, Bloomsbury, London, WC1E 7HX, UK.
| | - Klaudia B Ambroziak
- Department of Psychological Sciences, University of London, Malet Street, Bloomsbury, London, WC1E 7HX, UK
| | - Luigi Tamè
- Department of Psychological Sciences, University of London, Malet Street, Bloomsbury, London, WC1E 7HX, UK.,School of Psychology, University of Kent, Keyenes College, Canterbury, CT2 7NO, UK
| | - Alessandro Farnè
- Integrative Multisensory Perception Action & Cognition Team-ImpAct, Lyon Neuroscience Research Center, INSERM U1028, CNRS U5292, Lyon, France.,Claude Bernard University Lyon 1, 43 Boulevard du 11 Novembre 1918, 69100, Villeurbanne, France.,Hospices Civils de Lyon, Neuro-immersion, Villeurbanne, Lyon, France.,Centre for Mind/Brain Sciences, University of Trento, Corso Angelo, Corso Bettini, 31, 38068, Rovereto, TN, Italy
| | - Matthew R Longo
- Department of Psychological Sciences, University of London, Malet Street, Bloomsbury, London, WC1E 7HX, UK
| |
Collapse
|
11
|
Sorrentino G, Franza M, Zuber C, Blanke O, Serino A, Bassolino M. How ageing shapes body and space representations: A comparison study between healthy young and older adults. Cortex 2020; 136:56-76. [PMID: 33460913 DOI: 10.1016/j.cortex.2020.11.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 08/31/2020] [Accepted: 11/09/2020] [Indexed: 01/04/2023]
Abstract
To efficiently interact with the external world, the brain needs to represent the size of the involved body parts - body representations (BR) - and the space around the body in which the interactions with the environment take place - peripersonal space representation (PPS). BR and PPS are both highly flexible, being updated by the continuous flow of sensorimotor signals between the brain and the body, as observed for example after tool-use or immobilization. The progressive decline of sensorimotor abilities typically described in ageing could thus influence BR and PPS representations in the older adults. To explore this hypothesis, we compared BR and PPS in healthy young and older participants. By focusing on the upper limb, we adapted tasks previously used to evaluate BR and PPS plasticity, i.e., the body-landmarks localization task and audio-tactile interaction task, together with a new task targeting explicit BR (avatar adjustment task, AAT). Results show significantly higher distortions in the older rather than young participants in the perceived metric characteristic of the upper limbs. We found significant modifications in the implicit BR of the global shape (length and width) of both upper limbs, together with an underestimation in the arm length. Similar effects were also observed in the AAT task. Finally, both young and older adults showed equivalent multisensory facilitation in the space close to the hand, suggesting an intact PPS representation. Together, these findings demonstrated significant alterations of implicit and explicit BR in the older participants, probably associated with a less efficient contribution of bodily information typically subjected to age-related decline, whereas the comparable PPS representation in both groups could be supported by preserved multisensory abilities in older participants. These results provide novel empirical insight on how multiple representations of the body in space, subserving actions and perception, are shaped by the normal course of life.
Collapse
Affiliation(s)
- Giuliana Sorrentino
- Center for Neuroprosthetics, School of Life Science, Swiss Federal Institute of Technology (Ecole Polytechnique Fédérale de Lausanne), Campus Biotech, Geneva, Switzerland; Laboratory of Cognitive Neuroscience, Brain Mind Institute, School of Life Science, Swiss Federal Institute of Technology (Ecole Polytechnique Fédérale de Lausanne), Campus Biotech, Geneva, Switzerland; Center for Neuroprosthetics, School of Life Science, Swiss Federal Institute of Technology (Ecole Polytechnique Fédérale de Lausanne), Campus SUVA, Sion, Switzerland
| | - Matteo Franza
- Center for Neuroprosthetics, School of Life Science, Swiss Federal Institute of Technology (Ecole Polytechnique Fédérale de Lausanne), Campus Biotech, Geneva, Switzerland; Laboratory of Cognitive Neuroscience, Brain Mind Institute, School of Life Science, Swiss Federal Institute of Technology (Ecole Polytechnique Fédérale de Lausanne), Campus Biotech, Geneva, Switzerland; Center for Neuroprosthetics, School of Life Science, Swiss Federal Institute of Technology (Ecole Polytechnique Fédérale de Lausanne), Campus SUVA, Sion, Switzerland
| | - Charlène Zuber
- Center for Neuroprosthetics, School of Life Science, Swiss Federal Institute of Technology (Ecole Polytechnique Fédérale de Lausanne), Campus SUVA, Sion, Switzerland; Master of Science, University of Applied Sciences of Western, Switzerland
| | - Olaf Blanke
- Center for Neuroprosthetics, School of Life Science, Swiss Federal Institute of Technology (Ecole Polytechnique Fédérale de Lausanne), Campus Biotech, Geneva, Switzerland; Laboratory of Cognitive Neuroscience, Brain Mind Institute, School of Life Science, Swiss Federal Institute of Technology (Ecole Polytechnique Fédérale de Lausanne), Campus Biotech, Geneva, Switzerland; Center for Neuroprosthetics, School of Life Science, Swiss Federal Institute of Technology (Ecole Polytechnique Fédérale de Lausanne), Campus SUVA, Sion, Switzerland; Department of Neurology, University Hospital Geneva, Switzerland
| | - Andrea Serino
- Laboratory of Cognitive Neuroscience, Brain Mind Institute, School of Life Science, Swiss Federal Institute of Technology (Ecole Polytechnique Fédérale de Lausanne), Campus Biotech, Geneva, Switzerland; MySpace Lab, Department of Clinical Neuroscience, Centre Hospitalier Universitaire Vaudois (CHUV), Switzerland
| | - Michela Bassolino
- Laboratory of Cognitive Neuroscience, Brain Mind Institute, School of Life Science, Swiss Federal Institute of Technology (Ecole Polytechnique Fédérale de Lausanne), Campus Biotech, Geneva, Switzerland; Center for Neuroprosthetics, School of Life Science, Swiss Federal Institute of Technology (Ecole Polytechnique Fédérale de Lausanne), Campus SUVA, Sion, Switzerland; School of Health Sciences, HES-SO Valais-Wallis, Sion, Switzerland.
| |
Collapse
|
12
|
Van der Looven R, Deschrijver M, Hermans L, De Muynck M, Vingerhoets G. Hand size representation in healthy children and young adults. J Exp Child Psychol 2020; 203:105016. [PMID: 33246254 DOI: 10.1016/j.jecp.2020.105016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 09/21/2020] [Accepted: 09/22/2020] [Indexed: 10/22/2022]
Abstract
Whereas we experience our body as a coherent volumetric object, the brain appears to maintain highly fragmented representations of individual body parts. Little is known about how body representations of hand size and shape are built and evolve during infancy and young adulthood. This study aimed to investigate the effect of hand side, handedness, and age on the development of central hand size representation. The observational study with comparison groups was conducted with 90 typically developing Belgian school children and young adults (48 male and 42 female; age range = 5.0-23.0 years; 49 left-handed and 41 right-handed). Participants estimated their hand size and shape using two different tasks. In the localization task, participants were verbally cued to judge the locations of 10 anatomical landmarks of an occluded hand. An implicit hand size map was constructed and compared with actual hand dimensions. In the template selection task, the explicit hand shape was measured with a depictive method. Hand shape indexes were calculated and compared for the actual, implicit, and explicit conditions. Participants were divided into four age groups (5-8 years, 9-10 years, 11-16 years, and 17-23 years). Implicit hand maps featured underestimation of finger length and overestimation of hand width, which is already present in the youngest children. Linear mixed modeling revealed no influence of hand side on finger length underestimation; nonetheless, a significant main effect of age (p = .001) was exposed. Sinistrals aged 11 to 16 years showed significantly less underestimation (p = .03) than dextrals of the same age. As for the hand shape, the implicit condition differed significantly with the actual and explicit conditions (p < .001). Again, the implicit shape index was subjected to handedness and age effects, with significant differences being found between sinistrals and dextrals in the age groups of 9 and 10 years (p = .029) and 11 to 16 years (p < .001). In conclusion, the implicit metric component of the hand representation in children and young adults is misperceived, featuring shortened fingers and broadened hands since a very young age. Crucially, the finger length underestimation increases with age and shows a different developmental trajectory for sinistrals and dextrals. In contrast, the explicit hand shape is approximately veridical and seems immune from age and handedness effects. This study confirms the dual character of somatoperception and establishes a point of reference for children and young adults.
Collapse
Affiliation(s)
- Ruth Van der Looven
- Child Rehabilitation Centre, Department of Physical Medicine and Rehabilitation, Ghent University Hospital, 9000 Ghent, Belgium.
| | - Miguel Deschrijver
- Department of Physical Medicine and Rehabilitation, Ghent University Hospital, 9000 Ghent, Belgium
| | - Linda Hermans
- Child Rehabilitation Centre, Department of Physical Medicine and Rehabilitation, Ghent University Hospital, 9000 Ghent, Belgium
| | - Martine De Muynck
- Department of Physical Medicine and Rehabilitation, Ghent University Hospital, 9000 Ghent, Belgium
| | - Guy Vingerhoets
- Department of Experimental Psychology, Faculty of Psychology and Educational Sciences, Ghent University, 9000 Ghent, Belgium
| |
Collapse
|
13
|
Metric biases in body representation extend to objects. Cognition 2020; 206:104490. [PMID: 33217651 DOI: 10.1016/j.cognition.2020.104490] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Revised: 10/17/2020] [Accepted: 10/19/2020] [Indexed: 01/03/2023]
Abstract
We typically misestimate the dimensions of our body e.g., we perceive our fingers as shorter, and our torso as more elongated, than they actually are. It stands to reason that those metric biases may also extend to objects that we interact with, to facilitate attunement with the environment. To explore this hypothesis, we compared the metric representations of seven objects and the subjects' own hand using the Line Length Judgment task, in six experiments involving 152 healthy subjects. We evaluated the size estimation errors made for each target (hand or previously observed objects) by asking subjects to compare the vertical or horizontal dimension of a specific target against the length of a vertical or horizontal line. As expected, we showed that the hand is misperceived in its dimensions. Interestingly, we found that metric biases are also present for daily-life objects, such as a mobile phone and a coffee mug, and are not affected by familiarity with the objects. In contrast, objects that are less likely to be manipulated, either because they are potentially harmful or disgusting, were differently represented. Furthermore, the propensity to interact with an object, rated by an independent sample of subjects, best predicted the pattern of metric biases associated with that object. Taken together, these findings support the hypothesis that biases affecting the hand representation extend to objects that elicit action-oriented behavior, highlighting the importance of studying the body as integrated and active in the environment.
Collapse
|
14
|
Longo MR, Holmes M. Distorted perceptual face maps. Acta Psychol (Amst) 2020; 208:103128. [PMID: 32585432 DOI: 10.1016/j.actpsy.2020.103128] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 06/17/2020] [Accepted: 06/17/2020] [Indexed: 11/15/2022] Open
Abstract
Recent research has shown that proprioception relies on distorted representations of body size and shape. By asking participants to localise multiple landmarks in space, perceptual body maps can be constructed. Such maps of the hand and forearm is highly distorted, with large overestimation of limb width compared to length. Here, we investigated perceptual maps of the face, a body part central to our sense of self and personal identity. Participants localised 19 facial landmarks by pointing on a board covering their face. By comparing the relative location of judgments, we constructed perceptual face maps and compared them to actual face structure. These maps were massively distorted, with large overestimation of face width, but not length. This shows that distortions in perceptual body maps are not unique to the hand, but widespread on the body, including parts like the face at the core of our personal identity.
Collapse
Affiliation(s)
- Matthew R Longo
- Department of Psychological Sciences, Birkbeck, University of London, United Kingdom.
| | - Marie Holmes
- Department of Psychological Sciences, Birkbeck, University of London, United Kingdom
| |
Collapse
|
15
|
Perceptual Representation of Own Hand Size in Early Childhood and Adulthood. Sci Rep 2020; 10:5378. [PMID: 32214160 PMCID: PMC7096435 DOI: 10.1038/s41598-020-62206-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 03/11/2020] [Indexed: 11/29/2022] Open
Abstract
Hand size perceptual distortions characterize adult human cognition. Notwithstanding the importance of uncovering how hand size representation develops in humans, studies in this field are still at a preliminary stage. Indeed, it is yet to be understood whether hand size distortions are present and reliable in early childhood and whether they differ from adults’ distortions, offering a more in-depth insight into the emergence and development of such representations. We addressed this issue by comparing 4- to 6- year-old children and adults’ representation of their own hand size, as assessed with a 2-forced choice visual perceptual task. To test participants’ ability to estimate their own hand size, children and adults judged whether pictures of their own hand, resized to appear smaller or bigger than their own hand, matched or not its actual dimension. Results show that children aged 4 to 6 years tend to underestimate their own hand size, while adults underestimate their own hand more weakly. This evidence suggests that body-parts perceptual distortions are already in place in early childhood, and thus represent a characteristic of the human body representation.
Collapse
|
16
|
D’Amour S, Harris LR. The perceived size of the implicit representation of the dorsum and palm of the hand. PLoS One 2020; 15:e0230624. [PMID: 32203552 PMCID: PMC7089569 DOI: 10.1371/journal.pone.0230624] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 03/04/2020] [Indexed: 12/01/2022] Open
Abstract
The perception of the body and its parts has traditionally been studied using the conscious body image. Here, we determine the implicit representation of the hand. Participants were sequentially shown two life-size images of either the dorsal or palmar surface of their hand. In one interval either the horizontal or vertical dimension of the image was varied using an adaptive staircase, while the other interval contained the full-size, undistorted image. Participants reported which image most closely matched their hand. The staircase honed in on the distorted image that was equally likely to be judged as matching their own hand as the accurate image. The implicit representation was taken as midway between these two images. The experiment was repeated with different hand orientations. Perceived width depended on the orientation, with differences found between the upright and right orientations. Interestingly, the perceived length of the dorsum and palm were different from each other—length of the dorsum was overestimated whereas palm length was perceived accurately. This study reveals distortions of the implicit representation of the hands in healthy individuals.
Collapse
Affiliation(s)
- Sarah D’Amour
- Centre for Vision Research, York University, Toronto, Canada
- * E-mail:
| | | |
Collapse
|
17
|
Srismith D, Wider LM, Wong HY, Zipfel S, Thiel A, Giel KE, Behrens SC. Influence of Physical Activity Interventions on Body Representation: A Systematic Review. Front Psychiatry 2020; 11:99. [PMID: 32265747 PMCID: PMC7096574 DOI: 10.3389/fpsyt.2020.00099] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 02/06/2020] [Indexed: 11/13/2022] Open
Abstract
Distorted representation of one's own body is a diagnostic criterion and corepsychopathology of disorders such as anorexia nervosa and body dysmorphic disorder. Previousliterature has raised the possibility of utilising physical activity intervention (PI) as atreatment option for individuals suffering from poor body satisfaction, which is traditionallyregarded as a systematic distortion in "body image." In this systematic review,conducted according to the PRISMA statement, the evidence on effectiveness of PI on body representation outcomes is synthesised. We provide an update of 34 longitudinal studies evaluating the effectiveness of different types of PIs on body representation. No systematic risk of bias within or across studies were identified. The reviewed studies show that the implementation of structured PIs may be efficacious in increasing individuals' satisfaction of their own body, and thus improving their subjective body image related assessments. However, there is no clear evidence regarding an additional or interactive effect of PI when implemented in conjunction with established treatments for clinical populations. We argue for theoretically sound, mechanism-oriented, multimethod approaches to future investigations on body image disturbance. Specifically, we highlight the need to consider expanding the theoretical framework for the investigation of body representation disturbances to include further body representations besides body image.
Collapse
Affiliation(s)
- Duangkamol Srismith
- Medical University Hospital Tübingen, Department of Psychosomatic Medicine and Psychotherapy, Tübingen, Germany
- Max Planck Institute for Intelligent Systems, Department of Perceiving Systems, Tübingen, Germany
- Graduate Training Centre of Neuroscience, International Max Planck Research School, University of Tübingen, Tübingen, Germany
| | - Leona-Magdelena Wider
- Medical University Hospital Tübingen, Department of Psychosomatic Medicine and Psychotherapy, Tübingen, Germany
| | - Hong Yu Wong
- Werner Reichardt Centre for Integrative Neurosciences, University of Tübingen, Tübingen, Germany
- Department of Philosophy, University of Tübingen, Tübingen, Germany
| | - Stephan Zipfel
- Medical University Hospital Tübingen, Department of Psychosomatic Medicine and Psychotherapy, Tübingen, Germany
| | - Ansgar Thiel
- Institute of Sports Science, Faculty of Economic and Social Sciences, University of Tübingen, Tübingen, Germany
| | - Katrin Elisabeth Giel
- Medical University Hospital Tübingen, Department of Psychosomatic Medicine and Psychotherapy, Tübingen, Germany
| | - Simone Claire Behrens
- Medical University Hospital Tübingen, Department of Psychosomatic Medicine and Psychotherapy, Tübingen, Germany
- Max Planck Institute for Intelligent Systems, Department of Perceiving Systems, Tübingen, Germany
| |
Collapse
|
18
|
Stone KD, Kornblad CAE, Engel MM, Dijkerman HC, Blom RM, Keizer A. An Investigation of Lower Limb Representations Underlying Vision, Touch, and Proprioception in Body Integrity Identity Disorder. Front Psychiatry 2020; 11:15. [PMID: 32161554 PMCID: PMC7052367 DOI: 10.3389/fpsyt.2020.00015] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 01/08/2020] [Indexed: 01/26/2023] Open
Abstract
Individuals with Body Integrity Identity Disorder (BIID) have a (non-psychotic) longstanding desire to amputate or paralyze one or more fully-functioning limbs, often the legs. This desire presumably arises from experiencing a mismatch between one's perceived mental image of the body and the physical structural and/or functional boundaries of the body itself. While neuroimaging studies suggest a disturbed body representation network in individuals with BIID, few behavioral studies have looked at the manifestation of this disrupted lower limb representations in this population. Specifically, people with BIID feel like they are overcomplete in their current body. Perhaps sensory input, processed normally on and about the limb, cannot communicate with a higher-order model of the leg in the brain (which might be underdeveloped). We asked individuals who desire paralysis or amputation of the lower legs (and a group of age- and sex-matched controls) to make explicit and implicit judgments about the size and shape of their legs while relying on vision, touch, and proprioception. We hypothesized that BIID participants would mis-estimate the size of their affected leg(s) more than the same leg of controls. Using a multiple single-case analysis, we found no global differences in lower limb representations between BIID participants and controls. Thus, while people with BIID feel that part of the body is foreign, they can still make normal sensory-guided implicit and explicit judgments about the limb. Moreover, these results suggest that BIID is not a body image disorder, per se, and that an examination of leg representation does not uncover the disturbed bodily experience that individuals with BIID have.
Collapse
Affiliation(s)
- Kayla D. Stone
- Department of Experimental Psychology, Helmholtz Institute, Utrecht University, Utrecht, Netherlands
| | - Clara A. E. Kornblad
- Department of Experimental Psychology, Helmholtz Institute, Utrecht University, Utrecht, Netherlands
| | - Manja M. Engel
- Department of Experimental Psychology, Helmholtz Institute, Utrecht University, Utrecht, Netherlands
| | - H. Chris Dijkerman
- Department of Experimental Psychology, Helmholtz Institute, Utrecht University, Utrecht, Netherlands
| | - Rianne M. Blom
- Department of Psychiatry, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Anouk Keizer
- Department of Experimental Psychology, Helmholtz Institute, Utrecht University, Utrecht, Netherlands
| |
Collapse
|
19
|
Calabrò RS, Chillura A, Billeri L, Cannavò A, Buda A, Molonia F, Manuli A, Bramanti P, Naro A. Peri-Personal Space Tracing by Hand-Blink Reflex Modulation in Patients with Chronic Disorders of Consciousness. Sci Rep 2020; 10:1712. [PMID: 32015445 PMCID: PMC6997168 DOI: 10.1038/s41598-020-58625-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 01/17/2020] [Indexed: 12/14/2022] Open
Abstract
The assessment of awareness in patients with chronic Disorders of Consciousness (DoC), including Unresponsive Wakefulness Syndrome (UWS) and Minimally Conscious State (MCS), is challenging. The level of awareness impairment may depend on the degree of deterioration of the large-scale cortical-thalamo-cortical networks induced by brain injury. Electrophysiological approaches may shed light on awareness presence in patients with DoC by estimating cortical functions related to the cortical-thalamo-cortical networks including, for example, the cortico-subcortical processes generating motor responses to the perturbation of the peri-personal space (PPS). We measured the amplitude, latency, and duration of the hand-blink reflex (HBR) responses by recording electromyography (EMG) signals from both the orbicularis oculi muscles while electrically stimulating the median nerve at the wrist. Such a BR is thought to be mediated by a neural circuit at the brainstem level. Despite its defensive-response nature, HBR can be modulated by the distance between the stimulated hand and the face. This suggests a functional top-down control of HBR as reflected by HBR features changes (latency, amplitude, and magnitude). We therefore estimated HBR responses in a sample of patients with DoC (8 MCS and 12 UWS, compared to 15 healthy controls -HC) while performing a motor task targeting the PPS. This consisted of passive movements in which the hand of the subject was positioned at different distances from the participant's face. We aimed at demonstrating a residual top-down modulation of HBR properties, which could be useful to differentiate patients with DoC and, potentially, demonstrate awareness preservation. We found a decrease in latency, and an increase in duration and magnitude of HBR responses, which were all inversely related to the hand-to-face distance in HC and patients with MCS, but not in individuals with UWS. Our data suggest that only patients with MCS have preserved, residual, top-down modulation of the processes related to the PPS from higher-order cortical areas to sensory-motor integration network. Although the sample size was relatively small, being thus our data preliminary, HBR assessment seems a rapid, easy, and first-level tool to differentiate patients with MCS from those with UWS. We may also hypothesize that such a HBR modulation suggests awareness preservation.
Collapse
Affiliation(s)
| | | | - Luana Billeri
- IRCCS Centro Neurolesi Bonino Pulejo, Messina, Italy
| | | | - Antonio Buda
- IRCCS Centro Neurolesi Bonino Pulejo, Messina, Italy
| | | | | | | | - Antonino Naro
- IRCCS Centro Neurolesi Bonino Pulejo, Messina, Italy
| |
Collapse
|
20
|
Peviani V, Liotta J, Bottini G. The motor system (partially) deceives body representation biases in absence of visual correcting cues. Acta Psychol (Amst) 2020; 203:103003. [PMID: 31926426 DOI: 10.1016/j.actpsy.2020.103003] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 11/22/2019] [Accepted: 01/02/2020] [Indexed: 01/22/2023] Open
Abstract
The internal models of our body dimensions are prone to bias, but little evidence exists to explain how the motor system achieves fine-grained control despite these distortions. Previous work showed that the hand representation, assessed in a dynamic task (Proprioceptive Matching Task), was less distorted compared to that measured through a static body representation task (Localization Task), suggesting that either the hand representation was updated or the motor trajectory was adjusted during movement. The present study set out to shed light on this phenomenon by administering the Localization Task before and after either the Proprioceptive Matching Task or a control condition in a within-subjects design. Our results showed that hand map biases decreased during the Proprioceptive Matching Task, but that this increase in accuracy did not carry over to the Localization Task. In other words, more accurate performance in the dynamic body representation task does not reflect a change in how the hand is represented. Rather, it likely reflects a refinement of the motor trajectory, due to the integration of multisensory information, providing interesting insights into how the motor system partially overcomes biases in body representations.
Collapse
Affiliation(s)
- Valeria Peviani
- Department of Brain and Behavioural Sciences, University of Pavia, Via Bassi, 21, 27100 Pavia, Italy; Department of Neuroscience, Max Planck Institute for Empirical Aesthetics, Grüneburgweg 14, 60322 Frankfurt am Main, Germany.
| | - Jessica Liotta
- Department of Brain and Behavioural Sciences, University of Pavia, Via Bassi, 21, 27100 Pavia, Italy; Cognitive Neuropsychology Center, ASST Grande Ospedale Metropolitano Niguarda, Piazza dell'Ospedale Maggiore 3, 20162 Milan, Italy
| | - Gabriella Bottini
- Department of Brain and Behavioural Sciences, University of Pavia, Via Bassi, 21, 27100 Pavia, Italy; Cognitive Neuropsychology Center, ASST Grande Ospedale Metropolitano Niguarda, Piazza dell'Ospedale Maggiore 3, 20162 Milan, Italy; NeuroMI, Milan Center for Neuroscience, Italy
| |
Collapse
|
21
|
Peviani V, Melloni L, Bottini G. Visual and somatosensory information contribute to distortions of the body model. Sci Rep 2019; 9:13570. [PMID: 31537888 PMCID: PMC6753068 DOI: 10.1038/s41598-019-49979-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 08/16/2019] [Indexed: 11/09/2022] Open
Abstract
Distorted representations of the body are observed in healthy individuals as well as in neurological and psychiatric disorders. Distortions of the body model have been attributed to the somatotopic cerebral representation. Recently, it has been demonstrated that visual biases also contribute to those distortions. To better understand the sources of such distortions, we compared the metric representations across five body parts affording different degrees of tactile sensitivity and visual accessibility. We evaluated their perceived dimensions using a Line Length Judgment task. We found that most body parts were underestimated in their dimensions. The estimation error relative to their length was predicted by their tactile acuity, supporting the influence of the cortical somatotopy on the body model. However, tactile acuity did not explain the distortions observed for the width. Visual accessibility in turn does appear to mediate body distortions, as we observed that the dimensions of the dorsal portion of the neck were the only ones accurately perceived. Coherent with the multisensory nature of body representations, we argue that the perceived dimensions of body parts are estimated by integrating visual and somatosensory information, each weighted differently, based on their availability for a given body part and a given spatial dimension.
Collapse
Affiliation(s)
- Valeria Peviani
- Department of Brain and Behavioural Sciences, University of Pavia, Via Bassi 21, 27100, Pavia, Italy. .,Department of Neuroscience, Max Planck Institute for Empirical Aesthetics, Grüneburgweg 14, 60322, Frankfurt am Main, Germany.
| | - Lucia Melloni
- Department of Neuroscience, Max Planck Institute for Empirical Aesthetics, Grüneburgweg 14, 60322, Frankfurt am Main, Germany.,Department of Neurology, New York University School of Medicine, 240 East 38th St 10016, New York, NY, USA
| | - Gabriella Bottini
- Department of Brain and Behavioural Sciences, University of Pavia, Via Bassi 21, 27100, Pavia, Italy.,Cognitive Neuropsychology Center, ASST Grande Ospedale Metropolitano Niguarda, Piazza dell'Ospedale Maggiore 3, 20162, Milan, Italy.,NeuroMi, Milan Center for Neuroscience, Milan, Italy
| |
Collapse
|
22
|
Giurgola S, Pisoni A, Maravita A, Vallar G, Bolognini N. Somatosensory cortical representation of the body size. Hum Brain Mapp 2019; 40:3534-3547. [PMID: 31056809 PMCID: PMC6865590 DOI: 10.1002/hbm.24614] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 04/12/2019] [Accepted: 04/24/2019] [Indexed: 12/15/2022] Open
Abstract
The knowledge of the size of our own body parts is essential for accurately moving in space and efficiently interact with objects. A distorted perceptual representation of the body size often represents a core diagnostic criterion for some psychopathological conditions. The metric representation of the body was shown to depend on somatosensory afferences: local deafferentation indeed causes a perceptual distortion of the size of the anesthetized body part. A specular effect can be induced by altering the cortical map of body parts in the primary somatosensory cortex. Indeed, the present study demonstrates, in healthy adult participants, that repetitive Transcranial Magnetic Stimulation to the somatosensory cortical map of the hand in both hemispheres causes a perceptual distortion (i.e., an overestimation) of the size of the participants' own hand (Experiments 1-3), which does not involve other body parts (i.e., the foot, Experiment 2). Instead, the stimulation of the inferior parietal lobule of both hemispheres does not affect the perception of the own body size (Experiment 4). These results highlight the role of the primary somatosensory cortex in the building up and updating of the metric of body parts: somatosensory cortical activity not only shapes our somatosensation, it also affects how we perceive the dimension of our body.
Collapse
Affiliation(s)
- Serena Giurgola
- Department of Medicine and SurgeryPh.D. Program in Neuroscience, University of Milano‐BicoccaMonzaItaly
- Department of Psychology & Milan Center for Neuroscience (NeuroMI)University of Milano‐BicoccaMilanItaly
| | - Alberto Pisoni
- Department of Psychology & Milan Center for Neuroscience (NeuroMI)University of Milano‐BicoccaMilanItaly
| | - Angelo Maravita
- Department of Psychology & Milan Center for Neuroscience (NeuroMI)University of Milano‐BicoccaMilanItaly
| | - Giuseppe Vallar
- Department of Psychology & Milan Center for Neuroscience (NeuroMI)University of Milano‐BicoccaMilanItaly
- IRCCS Istituto Auxologico ItalianoLaboratory of NeuropsychologyMilanItaly
| | - Nadia Bolognini
- Department of Psychology & Milan Center for Neuroscience (NeuroMI)University of Milano‐BicoccaMilanItaly
- IRCCS Istituto Auxologico ItalianoLaboratory of NeuropsychologyMilanItaly
| |
Collapse
|
23
|
Towards prognostic functional brain biomarkers for cervical myelopathy: A resting-state fMRI study. Sci Rep 2019; 9:10456. [PMID: 31320690 PMCID: PMC6639260 DOI: 10.1038/s41598-019-46859-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 07/05/2019] [Indexed: 02/02/2023] Open
Abstract
Recently, there has been increasing interest in strategies to predict neurological recovery in cervical myelopathy (CM) based on clinical images of the cervical spine. In this study, we aimed to explore potential preoperative brain biomarkers that can predict postoperative neurological recovery in CM patients by using resting-state functional magnetic resonance imaging (rs-fMRI) and functional connectivity (FC) analysis. Twenty-eight patients with CM and 28 age- and sex-matched healthy controls (HCs) underwent rs-fMRI (twice for CM patients, before and six months after surgery). A seed-to-voxel analysis was performed, and the following three statistical analyses were conducted: (i) FC comparisons between preoperative CM and HC; (ii) correlation analysis between preoperative FCs and clinical scores; and (iii) postoperative FC changes in CM. Our analyses identified three FCs between the visual cortex and the right superior frontal gyrus based on the conjunction of the first two analyses [(i) and (ii)]. These FCs may act as potential biomarkers for postoperative gain in the 10-second test and might be sufficient to provide a prediction formula for potential recovery. Our findings provide preliminary evidence supporting the possibility of novel predictive measures for neurological recovery in CM using rs-fMRI.
Collapse
|
24
|
Abstract
Our body is a volumetric, three-dimensional (3-D) object in the world, and we experience it as such. Existing methods for measuring the perceptual body image, however, have been based on judgments of one-dimensional (1-D) length or two-dimensional images. We developed a new approach to the 3-D perceptual body image of the fingers by asking people to judge whether each finger would fit through rings of varying diameter. This task requires participants to conceptualize their finger as a volumetric object entering the ring. In two experiments, we used an adaptive staircase procedure to estimate the perceived size of each finger. There were systematic distortions of perceived 3-D finger size, with the size of index finger and (to a lesser extent) the middle finger underestimated. These distortions were unaffected by changes in hand posture. Notably, the pattern of distortions is qualitatively different from that found in previous research investigating 1-D finger length, suggesting that 3-D judgments of the body may differ in fundamental ways from 1-D judgments of individual body dimensions.
Collapse
Affiliation(s)
- Ebru Ecem Tavacioglu
- Department of Psychological Sciences, Birkbeck, University of London, UK; Department of Psychology, Ludwig-Maximilians-Universität Munchen, Munich, Germany; Psychology Department, Istanbul Sehir University, Turkey
| | - Elena Azañón
- Department of Psychological Sciences, Birkbeck, University of London, UK; Institute of Psychology, Otto von Guericke University Magdeburg, Germany; Center for Behavioral Brain Sciences, Otto von Guericke University Magdeburg, Germany; Department of Behavioral Neurology, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Matthew R Longo
- Department of Psychological Sciences, Birkbeck, University of London, UK
| |
Collapse
|
25
|
Sex differences in perceptual hand maps: A meta-analysis. Acta Psychol (Amst) 2019; 196:1-10. [PMID: 30933684 DOI: 10.1016/j.actpsy.2019.03.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 02/08/2019] [Accepted: 03/07/2019] [Indexed: 02/08/2023] Open
Abstract
A large body of research has suggested that localisation of the hand in external space relies on distorted representations of the hand. We developed a paradigm for measuring implicit perceptual maps of the hand (Longo & Haggard, 2010, Proc Natl Acad Sci USA, 107, 11727-11732), which show systematic deviation from actual hand shape, including overestimation of hand width and underestimation of finger length. Recently, Coelho and Gonzalez (in press, Psychol Res) reported sex differences in these perceptual hand maps, with women showing greater overestimation of hand width, but less underestimation of finger length than men. In the current study, I conducted a meta-analysis of 19 experiments using this paradigm by myself and my colleagues. The results replicated the sex differences reported by Coelho and Gonzalez. Importantly, however, these sex differences were not apparent when actual hand size was included as a covariate in analyses, suggesting that they may, at least in part, be due to women having smaller hands on average than men.
Collapse
|
26
|
Ingram LA, Butler AA, Gandevia SC, Walsh LD. Proprioceptive measurements of perceived hand position using pointing and verbal localisation tasks. PLoS One 2019; 14:e0210911. [PMID: 30653568 PMCID: PMC6336330 DOI: 10.1371/journal.pone.0210911] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 01/03/2019] [Indexed: 11/19/2022] Open
Abstract
Previous studies revealed that healthy individuals consistently misjudge the size and shape of their hidden hand during a localisation task. Specifically, they overestimate the width of their hand and underestimate the length of their fingers. This would also imply that the same individuals misjudge the actual location of at least some parts of their hand during the task. Therefore, the primary aim of the current study was to determine whether healthy individuals could accurately locate the actual position of their hand when hidden from view, and whether accuracy depends on the type of localisation task used, the orientation of the hidden hand, and whether the left or right hand is tested. Sixteen healthy right-handed participants performed a hand localisation task that involved both pointing to and verbally indicating the perceived position of landmarks on their hidden hand. Hand position was consistently misjudged as closer to the wrist (proximal bias) and, to a lesser extent, away from the thumb (ulnar bias). The magnitude of these biases depended on the localisation task (pointing vs. verbal), the orientation of the hand (straight vs. rotated), and the hand tested (left vs. right). Furthermore, the proximal location bias increased in size as the duration of the experiment increased, while the magnitude of ulnar bias remained stable through the experiment. Finally, the resultant maps of perceived hand location appear to replicate the previously reported overestimation of hand width and underestimation of finger length. Once again, the magnitude of these distortions is dependent on the task, orientation, and hand tested. These findings underscore the need to control and standardise each component of the hand localisation task in future studies.
Collapse
Affiliation(s)
- Lewis A. Ingram
- Neuroscience Research Australia, Sydney, New South Wales, Australia
- University of New South Wales, Sydney, New South Wales, Australia
| | - Annie A. Butler
- Neuroscience Research Australia, Sydney, New South Wales, Australia
- University of New South Wales, Sydney, New South Wales, Australia
| | - Simon C. Gandevia
- Neuroscience Research Australia, Sydney, New South Wales, Australia
- University of New South Wales, Sydney, New South Wales, Australia
| | - Lee D. Walsh
- Platypus Technical Consultants Pty Ltd, Canberra, Australia
| |
Collapse
|
27
|
Coelho LA, Schacher JP, Scammel C, Doan JB, Gonzalez CLR. Long- but not short-term tool-use changes hand representation. Exp Brain Res 2018; 237:137-146. [PMID: 30353213 DOI: 10.1007/s00221-018-5408-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 10/17/2018] [Indexed: 01/13/2023]
Abstract
Tool-use has been found to change body representation. For example, participants who briefly used a mechanical grabber to pick up objects perceived their forearms to be longer immediately after its use (e.g., Cardinali et al., Curr Biol 19(12):R478-R479, 2009; they incorporated the tool into their perceived arm size). While some studies have investigated the long-term effects of tool-use on body representation, none of these studies have used a tool that encapsulates the entire body part (e.g., a glove). Moreover, the relationship between tool-use and the body model (the representation of the body's spatial characteristics) has yet to be explored. To test this, we recruited 19 elite baseball players (EBP) and 18 age-matched controls to participate in a hand representation task. We included EBP because of their many years (8+) of training with a tool (baseball glove). The task required participants to place their hands underneath a covered glass tabletop (no vision of their hands), and to point to where they believed 10 locations (the tips and bases of each finger) were on their hands (Coelho et al., Psychol Res 81(6):1224-1231, 2017). Each point's XY coordinates was tracked using an Optotrak camera. From these coordinates, we mapped out the participants perceived hand size. The results showed that when compared to the controls, EBP underestimated hand width and finger length of both hands. This indicates that long-term tool use produces changes in the body model for both, the trained and untrained hands. We conducted a follow-up study to examine if 15 min of glove use would change perceived hand size in control participants. Novice baseball players (participants without baseball experience: NBP) were recruited and hand maps were derived before and after 15 min of active catching with a glove. Results showed no significant differences between the pre and post hand maps. When we compared between the two experiments, the EBP showed smaller hand representation for both hand width and finger length, than the NBP. We discuss these results in relation to theories of altered body ownership.
Collapse
Affiliation(s)
- Lara A Coelho
- The Brain in Action Laboratory, Department of Kinesiology and Physical Education, University of Lethbridge, Lethbridge, AB, T1K 3M4, Canada.
| | - Jason P Schacher
- The Brain in Action Laboratory, Department of Kinesiology and Physical Education, University of Lethbridge, Lethbridge, AB, T1K 3M4, Canada.,The Engineering and Human Performance Lab, Department of Kinesiology and Physical Education, University of Lethbridge, Lethbridge, AB, T1K 3M4, Canada
| | - Cory Scammel
- The Brain in Action Laboratory, Department of Kinesiology and Physical Education, University of Lethbridge, Lethbridge, AB, T1K 3M4, Canada.,The Engineering and Human Performance Lab, Department of Kinesiology and Physical Education, University of Lethbridge, Lethbridge, AB, T1K 3M4, Canada
| | - Jon B Doan
- The Engineering and Human Performance Lab, Department of Kinesiology and Physical Education, University of Lethbridge, Lethbridge, AB, T1K 3M4, Canada
| | - Claudia L R Gonzalez
- The Brain in Action Laboratory, Department of Kinesiology and Physical Education, University of Lethbridge, Lethbridge, AB, T1K 3M4, Canada
| |
Collapse
|
28
|
Peviani V, Bottini G. The distorted hand metric representation serves both perception and action. JOURNAL OF COGNITIVE PSYCHOLOGY 2018. [DOI: 10.1080/20445911.2018.1538154] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Valeria Peviani
- Brain and Behavioural Sciences Department, Università degli Studi di Pavia, Pavia, Italy
| | - Gabriella Bottini
- Brain and Behavioural Sciences Department, Università degli Studi di Pavia, Pavia, Italy
- Cognitive Neuropsychology Center, ASST Grande Ospedale Metropolitano Niguarda, Milano, Italy
- NeuroMi – Milan Center for Neuroscience, Milan, Italy
| |
Collapse
|
29
|
The effects of instrumental action on perceptual hand maps. Exp Brain Res 2018; 236:3113-3119. [DOI: 10.1007/s00221-018-5360-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Accepted: 08/10/2018] [Indexed: 11/30/2022]
|
30
|
Conceptual distortions of hand structure are robust to changes in stimulus information. Conscious Cogn 2018; 61:107-116. [DOI: 10.1016/j.concog.2018.01.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 11/10/2017] [Accepted: 01/08/2018] [Indexed: 12/18/2022]
|
31
|
Chubby hands or little fingers: sex differences in hand representation. PSYCHOLOGICAL RESEARCH 2018; 83:1375-1382. [PMID: 29616336 DOI: 10.1007/s00426-018-1003-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 03/30/2018] [Indexed: 12/24/2022]
Abstract
Disturbed body representation is a condition defined by the perception that one's body size is different from their anatomical size. While equal amounts of males and females suffer from disturbed body representation, there appear to be differences in the direction of this distortion. Females will typically overestimate, whereas males will typically underestimate body size. One part of the body that has been consistently misperceived is the hands. This misrepresentation consists of two distinct characteristics: an overestimation of hand width, and an underestimation of finger length. Many of these studies, however, have used predominately female participants, allowing for the possibility that women are driving this distortion. The aim of the present study was to examine possible sex differences in hand perception. To this end, participants estimated the location of ten landmarks on their hands when their hands were hidden from view. Our results indicate that females follow the characteristic distortion, whereas males only underestimate finger length (albeit more than females). These findings are surprising, because the hands are not an area of concern for weight gain/loss. We discuss these findings in relation to body dysmorphia literature.
Collapse
|
32
|
Stone KD, Keizer A, Dijkerman HC. The influence of vision, touch, and proprioception on body representation of the lower limbs. Acta Psychol (Amst) 2018; 185:22-32. [PMID: 29407242 DOI: 10.1016/j.actpsy.2018.01.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 09/27/2017] [Accepted: 01/16/2018] [Indexed: 11/25/2022] Open
Abstract
Numerous studies have shown that the representation of the hand is distorted. When participants are asked to localize unseen points on the hand (e.g. the knuckle), it is perceived to be wider and shorter than its physical dimensions. Similar distortions occur when people are asked to judge the distance between two tactile points on the hand; estimates made in the longitudinal direction are perceived as significantly shorter than those made in the transverse direction. Yet, when asked to visually compare the shape and size of one's own hand to a template hand, individuals are accurate at estimating the size of their own hands. Thus, it seems that body representations are, at least in part, a function of the most prominent underlying sensory modality used to perceive the body part. Yet, it remains unknown if the representations of other body parts are similarly distorted. The lower limbs, for example, are structurally and functionally very different from the hands, yet their representation(s) are seldom studied. What does the body representation for the leg look like? And is leg representation dependent on which sense is probed when making judgments about its shape and size? In the current study, we investigated what the representation of the leg looks like in visually-, tactually-, and proprioceptively-guided tasks. Results revealed that the leg, like the hand, is distorted in a highly systematic manner. Distortions seem to rely, at least partly, on sensory input. This is the first study, to our knowledge, to systematically investigate leg representation in healthy individuals.
Collapse
|
33
|
Cocchini G, Galligan T, Mora L, Kuhn G. The magic hand: Plasticity of mental hand representation. Q J Exp Psychol (Hove) 2018; 71:2314-2324. [DOI: 10.1177/1747021817741606] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Internal spatial body configurations are crucial to successfully interact with the environment and to experience our body as a three-dimensional volumetric entity. These representations are highly malleable and are modulated by a multitude of afferent and motor information. Despite some studies reporting the impact of sensory and motor modulation on body representations, the long-term relationship between sensory information and mental representation of own body parts is still unclear. We investigated hand representation in a group of expert sleight-of-hand magicians and in a group of age-matched adults naïve to magic (controls). Participants were asked to localise landmarks of their fingers when their hand position was congruent with the mental representation (Experiment 1) and when proprioceptive information was “misleading” (Experiment 2). Magicians outperformed controls in both experiments, suggesting that extensive training in sleight of hand has a profound effect in refining hand representation. Moreover, the impact of training seems to have a high body-part specificity, with a maximum impact for those body sections used more prominently during the training. Interestingly, it seems that sleight-of-hand training can lead to a specific improvement of hand mental representation, which relies less on proprioceptive information.
Collapse
Affiliation(s)
- Gianna Cocchini
- Department of Psychology, Goldsmiths, University of London, London, UK
| | - Toni Galligan
- Department of Psychology, Goldsmiths, University of London, London, UK
| | - Laura Mora
- Department of Psychology, Goldsmiths, University of London, London, UK
| | - Gustav Kuhn
- Department of Psychology, Goldsmiths, University of London, London, UK
| |
Collapse
|
34
|
Projecting the self outside the body: Body representations underlying proprioceptive imagery. Cognition 2017; 162:41-47. [DOI: 10.1016/j.cognition.2017.01.021] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 01/27/2017] [Accepted: 01/31/2017] [Indexed: 01/01/2023]
|
35
|
Longo MR. Expansion of Perceptual Body Maps Near - But Not Across - The Wrist. Front Hum Neurosci 2017; 11:111. [PMID: 28326030 PMCID: PMC5339231 DOI: 10.3389/fnhum.2017.00111] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 02/22/2017] [Indexed: 11/13/2022] Open
Abstract
Perceiving the external spatial location of touch requires that tactile information about the stimulus location on the skin be integrated with proprioceptive information about the location of the body in external space, a process called tactile spatial remapping. Recent results have suggested that this process relies on a distorted representation of the hand. Here, I investigated whether similar distortions are also found on the forearm and how they are affected by the presence of the wrist joint, which forms a categorical, segmental boundary between the hand and the arm. Participants used a baton to judge the perceived location of touches applied to their left hand or forearm. Similar distortions were apparent on both body parts, with overestimation of distances in the medio-lateral axis compared to the proximo-distal axis. There was no perceptual expansion of distances that crossed the wrist boundary. However, there was increased overestimation of distances near the wrist in the medio-lateral orientation. These results replicate recent findings of a distorted representation of the hand underlying tactile spatial remapping, and show that this effect is not idiosyncratic to the hand, but also affects the forearm. These distortions may be a general characteristic of the mental representation of the arms.
Collapse
Affiliation(s)
- Matthew R Longo
- Department of Psychological Sciences, Birkbeck, University of London London, UK
| |
Collapse
|