1
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Dopkins S. How is visual separation assessed? By counting distance units. Front Psychol 2024; 15:1410297. [PMID: 38873519 PMCID: PMC11169693 DOI: 10.3389/fpsyg.2024.1410297] [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: 03/31/2024] [Accepted: 05/14/2024] [Indexed: 06/15/2024] Open
Abstract
How does the human visual system assess the separation between pairs of stimuli in a frontal plane? According to the direct (or subtractive) view the system finds the difference between the positions of the stimuli in a localization system. According to the indirect (or additive) view the system finds the number of instances of a distance unit lying between representations of the stimuli. Critically, position is explicitly represented under the direct view, with separation being derived from position. Position is not explicitly represented under the indirect view; separation is consequently inferred by counting an internal unit of distance. Recent results favor the indirect over the direct view of separation assessment. Dissociations between assessments of separation and position, various context effects in the assessment of separation, and suggestions that position information is not cleanly accessed argue against the direct view. At the same time, various context effects in separation assessment argue for the indirect view. Recent findings regarding the brain bases of vision are consistent with the indirect view. In short, recent results suggest that assessing the separation between two frontal stimuli involves integrating distance units between representations of the stimuli.
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Affiliation(s)
- Stephen Dopkins
- Department of Psychological and Brain Sciences, George Washington University, Washington, DC, United States
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2
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Pratt S, Wand BM, Hince DA, Travers MJ, Schneider L, Kelly S, Gibson W. The characteristics of the implicit body model of the trunk. Perception 2024:3010066241248120. [PMID: 38706200 DOI: 10.1177/03010066241248120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/07/2024]
Abstract
Knowing where the body is in space requires reference to a stored model of the size and shape of body parts, termed the body model. This study sought to investigate the characteristics of the implicit body model of the trunk by assessing the position sense of midline and lateral body landmarks. Sixty-nine healthy participants localised midline and lateral body landmarks on their thorax, waist and hips, with perceived positions of these landmarks compared to actual positions. This study demonstrates evidence of a significant distortion of the implicit body model of the trunk, presenting as a squatter trunk, wider at the waist and hips. A significant difference was found between perceived and actual location in the horizontal (x) and vertical (y) directions for the majority of trunk landmarks. Evidence of a rightward bias was noted in the perception of six of the nine body landmarks in the horizontal (x) direction, including all midline levels. In the vertical (y) direction, a substantial inferior bias was evident at the thorax and waist. The implicit body model of the trunk is shown to be distorted, with the lumbar spine (waist-to-hip region) held to be shorter and wider than reality.
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Affiliation(s)
- Simon Pratt
- The University of Notre Dame Australia, Australia
| | | | - Dana A Hince
- The University of Notre Dame Australia, Australia
| | | | | | - Sara Kelly
- The University of Notre Dame Australia, Australia
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3
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Walsh E, Moreira C, Longo MR. Opposite size illusions for inverted faces and letters. Cognition 2024; 245:105733. [PMID: 38281395 DOI: 10.1016/j.cognition.2024.105733] [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: 06/05/2023] [Revised: 12/11/2023] [Accepted: 01/21/2024] [Indexed: 01/30/2024]
Abstract
Words are the primary means by which we communicate meaning and ideas, while faces provide important social cues. Studying visual illusions involving faces and words can elucidate the hierarchical processing of information as different regions of the brain are specialised for face recognition and word processing. A size illusion has previously been demonstrated for faces, whereby an inverted face is perceived as larger than the same stimulus upright. Here, two experiments replicate the face size illusion, and investigate whether the illusion is also present for individual letters (Experiment 1), and visual words and pseudowords (Experiment 2). Results confirm a robust size Illusion for faces. Letters, words and pseudowords and unfamiliar letters all show a reverse size illusion, as we previously demonstrated for human bodies. Overall, results indicate the illusion occurs in early perceptual stages upstream of semantic processing. Results are consistent with the idea of a general-purpose mechanism that encodes curvilinear shapes found in both scripts and our environment. Word and face perception rely on specialised, independent cognitive processes. The underestimation of the size of upright stimuli is specific to faces. Opposite size illusions may reflect differences in how size information is encoded and represented in stimulus-specialised neural networks, resulting in contrasting perceptual effects. Though words and faces differ visually, there is both symmetry and asymmetry in how the brain 'reads' them.
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Affiliation(s)
- Eamonn Walsh
- Department of Basic & Clinical Neuroscience, Institute of Psychiatry, Psychology & Neuroscience, King's College London, UK; Cultural and Social Neuroscience Research Group, Institute of Psychiatry, Psychology & Neuroscience, King's College London, UK.
| | - Carolina Moreira
- Department of Psychological Sciences, Birkbeck, University of London, UK
| | - Matthew R Longo
- Department of Psychological Sciences, Birkbeck, University of London, UK
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4
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Risso G, Bassolino M. Assess and rehabilitate body representations via (neuro)robotics: An emergent perspective. Front Neurorobot 2022; 16:964720. [PMID: 36160286 PMCID: PMC9498221 DOI: 10.3389/fnbot.2022.964720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 08/02/2022] [Indexed: 11/23/2022] Open
Abstract
The perceptions of our own body (e.g., size and shape) do not always coincide with its real characteristics (e.g., dimension). To track the complexity of our perception, the concept of mental representations (model) of the body has been conceived. Body representations (BRs) are stored in the brain and are maintained and updated through multiple sensory information. Despite being altered in different clinical conditions and being tightly linked with self-consciousness, which is one of the most astonishing features of the human mind, the BRs and, especially, the underlying mechanisms and functions are still unclear. In this vein, here we suggest that (neuro)robotics can make an important contribution to the study of BRs. The first section of the study highlights the potential impact of robotics devices in investigating BRs. Far to be exhaustive, we illustrate major examples of its possible exploitation to further improve the assessment of motor, haptic, and multisensory information building up the BRs. In the second section, we review the main evidence showing the contribution of neurorobotics-based (multi)sensory stimulation in reducing BRs distortions in various clinical conditions (e.g., stroke, amputees). The present study illustrates an emergent multidisciplinary perspective combining the neuroscience of BRs and (neuro)robotics to understand and modulate the perception and experience of one's own body. We suggest that (neuro)robotics can enhance the study of BRs by improving experimental rigor and introducing new experimental conditions. Furthermore, it might pave the way for the rehabilitation of altered body perceptions.
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Affiliation(s)
- Gaia Risso
- School of Health Sciences, Haute École spécialisée de Suisse occidentale (HES-SO) Valais-Wallis, Sion, Switzerland
- The Sense Innovation and Research Center, Sion, Switzerland
- Robotics, Brain and Cognitive Sciences (RBCS), Istituto Italiano di Tecnologia, Genoa, Italy
| | - Michela Bassolino
- School of Health Sciences, Haute École spécialisée de Suisse occidentale (HES-SO) Valais-Wallis, Sion, Switzerland
- The Sense Innovation and Research Center, Sion, Switzerland
- Laboratoire MySpace, Université de Lausanne, Lausanne, Switzerland
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5
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Tamè L, Limbu S, Harlow R, Parikh M, Longo MR. Size Constancy Mechanisms: Empirical Evidence from Touch. Vision (Basel) 2022; 6:vision6030040. [PMID: 35893757 PMCID: PMC9326730 DOI: 10.3390/vision6030040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 06/10/2022] [Accepted: 06/14/2022] [Indexed: 11/30/2022] Open
Abstract
Several studies have shown the presence of large anisotropies for tactile distance perception across several parts of the body. The tactile distance between two touches on the dorsum of the hand is perceived as larger when they are oriented mediolaterally (across the hand) than proximodistally (along the hand). This effect can be partially explained by the characteristics of primary somatosensory cortex representations. However, this phenomenon is significantly attenuated relative to differences in acuity and cortical magnification, suggesting a process of tactile size constancy. It is unknown whether the same kind of compensation also takes place when estimating the size of a continuous object. Here, we investigate whether the tactile anisotropy that typically emerges when participants have to estimate the distance between two touches is also present when a continuous object touches the skin and participants have to estimate its size. In separate blocks, participants judged which of two tactile distances or objects on the dorsum of their hand felt larger. One stimulation (first or second) was aligned with the proximodistal axis (along the hand) and the other with the mediolateral axis (across the hand). Results showed a clear anisotropy for distances between two distinct points, with across distances consistently perceived as larger than along distances, as in previous studies. Critically, however, this bias was significantly reduced or absent for judgments of the length of continuous objects. These results suggest that a tactile size constancy process is more effective when the tactile size of an object has to be approximated compared to when the distance between two touches has to be determined. The possible mechanism subserving these results is described and discussed. We suggest that a lateral inhibition mechanism, when an object touches the skin, provides information through the distribution of the inhibitory subfields of the RF about the shape of the tactile RF itself. Such a process allows an effective tactile size compensatory mechanism where a good match between the physical and perceptual dimensions of the object is achieved.
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Affiliation(s)
- Luigi Tamè
- School of Psychology, University of Kent, Canterbury CT2 7NP, UK
- Department of Psychological Sciences, Birkbeck, University of London, London WC1E 7HX, UK; (S.L.); (R.H.); (M.P.)
- Correspondence: (L.T.); (M.R.L.)
| | - Suzuki Limbu
- Department of Psychological Sciences, Birkbeck, University of London, London WC1E 7HX, UK; (S.L.); (R.H.); (M.P.)
| | - Rebecca Harlow
- Department of Psychological Sciences, Birkbeck, University of London, London WC1E 7HX, UK; (S.L.); (R.H.); (M.P.)
| | - Mita Parikh
- Department of Psychological Sciences, Birkbeck, University of London, London WC1E 7HX, UK; (S.L.); (R.H.); (M.P.)
| | - Matthew R. Longo
- Department of Psychological Sciences, Birkbeck, University of London, London WC1E 7HX, UK; (S.L.); (R.H.); (M.P.)
- Correspondence: (L.T.); (M.R.L.)
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6
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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.
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7
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The distorted body: The perception of the relative proportions of the body is preserved in Parkinson's disease. Psychon Bull Rev 2022; 29:1317-1326. [PMID: 35445288 PMCID: PMC9020551 DOI: 10.3758/s13423-022-02099-9] [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] [Accepted: 03/29/2022] [Indexed: 11/08/2022]
Abstract
Given humans' ubiquitous visual experience of their own body, one reasonable assumption is that one's perceptions of the lengths of their body parts should be accurate. However, recent research has shown that large systematic distortions of the length of body parts are present in healthy younger adults. These distortions appear to be linked to tactile sensitivity such that individuals overestimate the length of body parts of low tactile sensitivity to a greater extent than body parts of high tactile sensitivity. There are certain conditions featuring reduced tactile sensitivity, such as Parkinson's disease (PD) and healthy older ageing. However, the effect of these circumstances on individuals' perceptions of the lengths of their body parts remains unknown. In this study, participants visually estimated the length of their body parts using their hand as a metric. We show that despite the reductions in tactile sensitivity, and potential alterations in the cortical presentation of body parts that may occur in PD and healthy older ageing, individuals with mild-moderate PD and older adults of comparable age experience body size distortions comparable to healthy younger controls. These findings demonstrate that the ability to perceive the length of one's body parts is well preserved in mild-moderate PD.
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8
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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.
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Affiliation(s)
- Matthew R Longo
- Department of Psychological Sciences, Birkbeck, University of London, Malet Street, London WC1E 7HX, UK.
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9
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Dupin L, Cuenca M, Baron JC, Maier MA, Lindberg PG. Shrinking of spatial hand representation but not of objects across the lifespan. Cortex 2021; 146:173-185. [PMID: 34883309 DOI: 10.1016/j.cortex.2021.10.009] [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: 05/17/2021] [Revised: 09/02/2021] [Accepted: 10/22/2021] [Indexed: 11/17/2022]
Abstract
Perception and action are based on cerebral spatial representations of the body and the external world. However, spatial representations differ from the physical characteristics of body and external space (e.g., objects). It remains unclear whether these discrepancies are related to functional requirements of action and are shared between different spatial representations, indicating common brain processes. We hypothesized that distortions of spatial hand representation would be affected by age, sensorimotor practice and external space representation. We assessed hand representations using tactile and verbal localization tasks and quantified object representation in three age groups (20-79 yrs, total n = 60). Our results show significant shrinking of spatial hand representations (hand width) with age, unrelated to sensorimotor functions. No such shrinking occurred in spatial object representations despite some common characteristics with hand representations. Therefore, spatial properties of body representation partially share characteristics of object representation but also evolve independently across the lifespan.
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Affiliation(s)
- Lucile Dupin
- Institut de Psychiatrie et Neurosciences de Paris, Inserm U1266, Université de Paris, Paris, France.
| | - Macarena Cuenca
- Centre de Recherche Clinique, GHU, Hôpital Sainte-Anne, Paris, France
| | - Jean-Claude Baron
- Institut de Psychiatrie et Neurosciences de Paris, Inserm U1266, Université de Paris, Paris, France
| | - Marc A Maier
- Université de Paris, INCC UMR 8002, CNRS, Paris, France
| | - Påvel G Lindberg
- Institut de Psychiatrie et Neurosciences de Paris, Inserm U1266, Université de Paris, Paris, France
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10
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Abstract
Perception of distance between two touches varies with orientation on the hand, with distances aligned with hand width perceived as larger than those aligned with hand length. Similar anisotropies are found on other body parts (e.g., the face), suggesting they may reflect a general feature of tactile organization, but appear absent on other body parts (e.g., the belly). Here, we investigated tactile-distance anisotropy on the foot, a body part structurally and embryologically similar to the hand, but with very different patterns of functional usage in humans. In three experiments, we compared the perceived distance between pairs of touches aligned with the medio-lateral and proximal-distal foot axes. On the hairy skin of the foot dorsum, anisotropy was consistently found, with distances aligned with the medio-lateral foot axis perceived as larger than those in the proximo-distal axis. In contrast, on the glabrous skin of the sole, inconsistent results were found across experiments, with no overall evidence for anisotropy. This shows a pattern of anisotropy on the foot broadly similar to that on the hand, adding to the list of body parts showing tactile-distance anisotropy, and providing further evidence that such biases are a general aspect of tactile spatial organization across the body. Significance: The perception of tactile distance has been widely used to understand the spatial structure of touch. On the hand, anisotropy of tactile distance perception is well established, with distances oriented across hand width perceived larger than those oriented along hand length. We investigated tactile-distance anisotropy on the feet, a body part structurally, genetically, and developmentally homologous to the hands, but with strikingly different patterns of functional usage. We report highly similar patterns of anisotropy on the hairy skin of the hand dorsum and foot dorsum. This suggests that anisotropy arises from the general organization of touch across the body.
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11
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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.
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12
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Differential effects of minified and magnified mirror visual feedback on the underlying misperception of hand size. Atten Percept Psychophys 2021; 83:2281-2290. [PMID: 33754299 PMCID: PMC8213598 DOI: 10.3758/s13414-021-02262-9] [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] [Accepted: 01/25/2021] [Indexed: 11/08/2022]
Abstract
Perception of the size of body parts, for instance the hand, has been shown to be distorted in healthy participants, with over- and underestimations of width and length, respectively. Illusory manipulations of body shape and size have highlighted the flexibility of the body representation and have also been found to update immediate perceptions of body size and surrounding objects. Here, we examined whether underlying misperceptions of hand width and length can be modified through exposure to illusory changes in hand size using a mirror visual feedback (MVF) paradigm. While questionnaire responses indicated subjective susceptibility to both magnified and minified manipulations, objective hand size estimates only showed significant differences following exposure to minifying mirrors. These variations might reflect differences in the way that stored representations are accessed or updated in response to size manipulations. Secondly, the findings further reinforce differences between subjective and objective outcomes of illusions on subsequent body perception.
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13
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Tamè L, Tucciarelli R, Sadibolova R, Sereno MI, Longo MR. Reconstructing neural representations of tactile space. Neuroimage 2021; 229:117730. [PMID: 33454399 DOI: 10.1016/j.neuroimage.2021.117730] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 11/18/2020] [Accepted: 01/07/2021] [Indexed: 01/29/2023] Open
Abstract
Psychophysical experiments have demonstrated large and highly systematic perceptual distortions of tactile space. Such a space can be referred to our experience of the spatial organisation of objects, at representational level, through touch, in analogy with the familiar concept of visual space. We investigated the neural basis of tactile space by analysing activity patterns induced by tactile stimulation of nine points on a 3 × 3 square grid on the hand dorsum using functional magnetic resonance imaging. We used a searchlight approach within pre-defined regions of interests to compute the pairwise Euclidean distances between the activity patterns elicited by tactile stimulation. Then, we used multidimensional scaling to reconstruct tactile space at the neural level and compare it with skin space at the perceptual level. Our reconstructions of the shape of skin space in contralateral primary somatosensory and motor cortices reveal that it is distorted in a way that matches the perceptual shape of skin space. This suggests that early sensorimotor areas critically contribute to the distorted internal representation of tactile space on the hand dorsum.
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Affiliation(s)
- Luigi Tamè
- Department of Psychological Sciences, Birkbeck, University of London, London WC1E 7HX, UK; School of Psychology, University of Kent, Canterbury CT2 7NP, UK.
| | - Raffaele Tucciarelli
- Department of Psychological Sciences, Birkbeck, University of London, London WC1E 7HX, UK
| | - Renata Sadibolova
- Department of Psychological Sciences, Birkbeck, University of London, London WC1E 7HX, UK; Department of Psychology, Goldsmith, University of London, London, UK
| | - Martin I Sereno
- Department of Psychological Sciences, Birkbeck, University of London, London WC1E 7HX, UK; University College London, University of London, London, UK; San Diego State University, San Diego, USA
| | - Matthew R Longo
- Department of Psychological Sciences, Birkbeck, University of London, London WC1E 7HX, UK.
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14
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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.
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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
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15
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Barra J, Giroux M, Metral M, Cian C, Luyat M, Kavounoudias A, Guerraz M. Functional properties of extended body representations in the context of kinesthesia. Neurophysiol Clin 2020; 50:455-465. [PMID: 33176990 DOI: 10.1016/j.neucli.2020.10.011] [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: 09/02/2020] [Revised: 10/16/2020] [Accepted: 10/16/2020] [Indexed: 12/18/2022] Open
Abstract
A person's internal representation of his/her body is not fixed. It can be substantially modified by neurological injuries and can also be extended (in healthy participants) to incorporate objects that have a corporeal appearance (such as fake body segments, e.g. a rubber hand), virtual whole bodies (e.g. avatars), and even objects that do not have a corporeal appearance (e.g. tools). Here, we report data from patients and healthy participants that emphasize the flexible nature of body representation and question the extent to which incorporated objects have the same functional properties as biological body parts. Our data shed new light by highlighting the involvement of visual motion information from incorporated objects (rubber hands, full body avatars and hand-held tools) in the perception of one's own movement (kinesthesia). On the basis of these findings, we argue that incorporated objects can be treated as body parts, especially when kinesthesia is involved.
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Affiliation(s)
- Julien Barra
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, LPNC, 38000 Grenoble, France
| | - Marion Giroux
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, LPNC, 38000 Grenoble, France
| | - Morgane Metral
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, LIP/PC2S, Grenoble, France
| | - Corinne Cian
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, LPNC, 38000 Grenoble, France; Institut de Recherche Biomédicale des Armées, Brétigny sur Orge, France
| | - Marion Luyat
- Univ. Lille, URL 4072 - PSITEC - Psychologie : Interactions, Temps, Emotions, Cognition, F-59000 Lille, France
| | - Anne Kavounoudias
- Aix-Marseille University, CNRS, LNSC UMR 7260, F-13331 Marseille, France
| | - Michel Guerraz
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, LPNC, 38000 Grenoble, France.
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16
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Risso G, Martoni RM, Erzegovesi S, Bellodi L, Baud-Bovy G. Visuo-tactile shape perception in women with Anorexia Nervosa and healthy women with and without body concerns. Neuropsychologia 2020; 149:107635. [PMID: 33058922 DOI: 10.1016/j.neuropsychologia.2020.107635] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 09/18/2020] [Accepted: 09/19/2020] [Indexed: 10/23/2022]
Abstract
A key feature of Anorexia Nervosa is body image disturbances, the study of which has focused mainly on visual and attitudinal aspects, did not always contain homogeneous groups of patients, and/or did not evaluate body shape concerns of the control group. In this study, we used psychophysical methods to investigate the visual, tactile and bimodal perception of elliptical shapes in a group of patients with Anorexia Nervosa (AN) restricting type and two groups of healthy participants, which differed from each other by the presence of concerns about their own bodies. We used an experimental paradigm designed to test the hypothesis that the perceptual deficits in AN reflect an impairment in multisensory integration. The results showed that the discrimination thresholds of AN patients are larger than those of the two control groups. While all participants overestimated the width of the ellipses, this distortion was more pronounced in AN patients and, to a lesser extent, healthy women concerned about their bodies. All groups integrated visual and tactile information similarly in the bimodal conditions, which does not support the multi-modal integration impairment hypothesis. We interpret these results within an integrated model of perceptual deficits of Anorexia Nervosa based on a model of somatosensation that posits a link between object tactile perception and Mental Body Representations. Finally, we found that the participants' perceptual abilities were correlated with their clinical scores. This result should encourage further studies that aim at evaluating the potential of perceptual indexes as a tool to support clinical practices.
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Affiliation(s)
- G Risso
- DIBRIS, University of Genova, Genova, Italy; RBCS, Istituto Italiano di Tecnologia, Genova, Italy
| | | | | | - L Bellodi
- Ospedale San Raffaele, Milan, Italy; Faculty of Psychology, Università San Raffaele Vita Salute, Milan, Italy
| | - G Baud-Bovy
- RBCS, Istituto Italiano di Tecnologia, Genova, Italy; Faculty of Psychology, Università San Raffaele Vita Salute, Milan, Italy.
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17
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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.
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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
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18
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Hidaka S, Tucciarelli R, Azañón E, Longo MR. Tactile distance adaptation aftereffects do not transfer to perceptual hand maps. Acta Psychol (Amst) 2020; 208:103090. [PMID: 32485337 DOI: 10.1016/j.actpsy.2020.103090] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 05/08/2020] [Accepted: 05/12/2020] [Indexed: 12/26/2022] Open
Abstract
Recent studies have demonstrated that mental representations of the hand dorsum are distorted even for healthy participants. Perceptual hand maps estimated by pointing to specific landmarks (e.g., knuckles and tips of fingers) is stretched and shrunk along the medio-lateral and the proximo-distal axes, respectively. Similarly, tactile distance perception between two touches is longer along the medio-lateral axis than the proximo-distal axis. The congruency of the two types of distortions suggests that common perceptual and neural representations may be involved in these processes. Prolonged stimulation by two simultaneous touches having a particular distance can bias subsequent perception of tactile distances (e.g., adaptation to a long distance induces shorter stimuli to be perceived even shorter). This tactile distance adaptation aftereffect has been suggested to occur based on the modulations of perceptual and neural responses at low somatosensory processing stages. The current study investigated whether tactile distance adaptation aftereffects affect also the pattern of distortions on the perceptual hand maps. Participants localized locations on the hand dorsum cued by tactile stimulations (Experiment 1) or visually presented landmarks on a hand silhouette (Experiment 2). Each trial was preceded by adaptation to either a small (2 cm) or large (4 cm) tactile distance. We found clear tactile distance aftereffects. However, no changes were observed for the distorted pattern of the perceptual hand maps following adaptation to a tactile distance. Our results showed that internal body representations involved in perceptual distortions may be distinct between tactile distance perception and the perceptual hand maps underlying position sense.
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Affiliation(s)
- Souta Hidaka
- Department of Psychology, Rikkyo University, 1-2-26, Kitano, Niiza-shi, Saitama 352-8558, Japan; Department of Psychological Sciences, Birkbeck, University of London, United Kingdom.
| | - Raffaele Tucciarelli
- Department of Psychological Sciences, Birkbeck, University of London, United Kingdom
| | - Elena Azañón
- Institute of Psychology, Otto-von-Guericke University, Universitätsplatz 2, 39106 Magdeburg, Germany; Department of Behavioral Neurology, Leibniz Institute for Neurobiology, Brenneckestraße 6, Magdeburg 39118, Germany; Center for Behavioral Brain Sciences, Universitätsplatz 2, Magdeburg 39106, Germany
| | - Matthew R Longo
- Department of Psychological Sciences, Birkbeck, University of London, United Kingdom
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19
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Anisotropy in tactile time perception. Cortex 2020; 128:124-131. [DOI: 10.1016/j.cortex.2020.03.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2019] [Revised: 01/26/2020] [Accepted: 03/01/2020] [Indexed: 11/17/2022]
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20
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Cleary M, Kornhaber R, Thapa DK, West S, Visentin D. A quantitative systematic review assessing the impact of burn injuries on body image. Body Image 2020; 33:47-65. [PMID: 32109831 DOI: 10.1016/j.bodyim.2020.02.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 02/17/2020] [Accepted: 02/17/2020] [Indexed: 10/24/2022]
Abstract
This study systematically reviewed the quantitative evidence for the impact of burn injuries on body image. Primary research assessing body image using standardized scales published in peer-reviewed journals were systematically searched using the electronic databases PubMed, Scopus, CINHAL, and PsycINFO in January 2020. Studies reporting relationships between characteristics related to burn injury and body image outcomes were included. Quality was assessed using the JBI Critical Appraisal Checklist for Analytical Cross-Sectional Studies. Included studies varied in comparison methods and body image measures, with most reporting cross-sectional relationships. Among the 33 included studies, 12 reported a negative association between burn severity and body image, 14 reported no significant association, six showed mixed (negative and null) results across the burn injury measures, and one reported more positive body image among burn survivors compared to those without burns. This review identified evidence supporting the association between burn severity and lower satisfaction with body image. Individuals with body image concerns, particularly those with higher burn severity and women, may benefit most from interventions that address self-acceptance and coping mechanisms. Further cross-sectional studies with representative control groups and longitudinal studies with longer follow-up periods are required.
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Affiliation(s)
- Michelle Cleary
- College of Health and Medicine, University of Tasmania, Sydney, NSW, Australia.
| | - Rachel Kornhaber
- College of Health and Medicine, University of Tasmania, Sydney, NSW, Australia; National Burns Center, Sheba Medical Center, Tel Hashomer, Israel
| | | | - Sancia West
- College of Health and Medicine, University of Tasmania, Sydney, NSW, Australia
| | - Denis Visentin
- College of Health and Medicine, University of Tasmania, Sydney, NSW, Australia
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21
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Viceconti A, Camerone EM, Luzzi D, Pentassuglia D, Pardini M, Ristori D, Rossettini G, Gallace A, Longo MR, Testa M. Explicit and Implicit Own's Body and Space Perception in Painful Musculoskeletal Disorders and Rheumatic Diseases: A Systematic Scoping Review. Front Hum Neurosci 2020; 14:83. [PMID: 32327984 PMCID: PMC7161420 DOI: 10.3389/fnhum.2020.00083] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 02/24/2020] [Indexed: 12/21/2022] Open
Abstract
Background: Pain and body perception are essentially two subjective mutually influencing experiences. However, in the field of musculoskeletal disorders and rheumatic diseases we lack of a comprehensive knowledge about the relationship between body perception dysfunctions and pain or disability. We systematically mapped the literature published about the topics of: (a) somatoperception; (b) body ownership; and (c) perception of space, analysing the relationship with pain and disability. The results were organized around the two main topics of the assessment and treatment of perceptual dysfunctions. Methods: This scoping review followed the six-stage methodology suggested by Arksey and O'Malley. Ten electronic databases and grey literature were systematically searched. The PRISMA Extension for Scoping Reviews was used for reporting results. Two reviewers with different background, independently performed study screening and selection, and one author performed data extraction, that was checked by a second reviewer. Results: Thirty-seven studies fulfilled the eligibility criteria. The majority of studies (68%) concerned the assessment methodology, and the remaining 32% investigated the effects of therapeutic interventions. Research designs, methodologies adopted, and settings varied considerably across studies. Evidence of distorted body experience were found mainly for explicit somatoperception, especially in studies adopting self-administered questionnaire and subjective measures, highlighting in some cases the presence of sub-groups with different perceptual features. Almost half of the intervention studies (42%) provided therapeutic approaches combining more than one perceptual task, or sensory-motor tasks together with perceptual strategies, thus it was difficult to estimate the relative effectiveness of each single therapeutic component. Conclusions: To our knowledge, this is the first attempt to systematically map and summarize this research area in the field of musculoskeletal disorders and rheumatic diseases. Although methodological limitations limit the validity of the evidence obtained, some strategies of assessment tested and therapeutic strategies proposed represent useful starting points for future research. This review highlights preliminary evidence, strengths, and limitations of the literature published about the research questions, identifying key points that remain opened to be addressed, and make suggestions for future research studies. Body representation, as well as pain perception and treatment, can be better understood if an enlarged perspective including body and space perception is considered.
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Affiliation(s)
- Antonello Viceconti
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Savona, Italy
| | - Eleonora Maria Camerone
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Savona, Italy
| | - Deborah Luzzi
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Savona, Italy
| | - Debora Pentassuglia
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Savona, Italy
| | - Matteo Pardini
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Genoa, Italy.,Policlinico S. Martino IRCCS, Genova, Italy
| | - Diego Ristori
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Savona, Italy
| | - Giacomo Rossettini
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Savona, Italy
| | - Alberto Gallace
- Neuromi, Università di Milano-Bicocca, Milan, Italy.,Mind and Behavior Technological Center- Mibtec, Università di Milano-Bicocca, Milan, Italy
| | - Matthew R Longo
- Department of Psychological Sciences, Birkbeck, University of London, London, United Kingdom
| | - Marco Testa
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Savona, Italy
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22
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Knight FLC, Bremner AJ, Cowie D. Does the language we use to segment the body, shape the way we perceive it? A study of tactile perceptual distortions. Cognition 2020; 197:104127. [DOI: 10.1016/j.cognition.2019.104127] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 11/01/2019] [Accepted: 11/04/2019] [Indexed: 10/25/2022]
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23
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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.
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24
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25
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Abstract
Cortical body size representations are distorted in the adult, from low-level motor and sensory maps to higher levels multisensory and cognitive representations. Little is known about how such representations are built and evolve during infancy and childhood. Here we investigated how hand size is represented in typically developing children aged 6 to 10. Participants were asked to estimate their hand size using two different sensory modalities (visual or haptic). We found a distortion (underestimation) already present in the youngest children. Crucially, such distortion increases with age and regardless of the sensory modality used to access the representation. Finally, underestimation is specific for the body as no bias was found for object estimation. This study suggests that the brain does not keep up with the natural body growth. However, since motor behavior nor perception were impaired, the distortion seems functional and/or compensated for, for proper interaction with the external environment.
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26
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Gadsby S. Body representations and cognitive ontology: Drawing the boundaries of the body image. Conscious Cogn 2019; 74:102772. [PMID: 31280098 DOI: 10.1016/j.concog.2019.102772] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Revised: 06/18/2019] [Accepted: 06/19/2019] [Indexed: 10/26/2022]
Abstract
The distinction between body image and body schema has been incredibly influential in cognitive neuroscience. Recently, researchers have begun to speculate about the relationship between these representations (Gadsby, 2017, 2018; Pitron & de Vignemont, 2017; Pitron et al., 2018). Within this emerging literature, Pitron et al. (2018) proposed that the long-term body image and long-term body schema co-construct one another, through a process of reciprocal interaction. In proposing this model, they make two assumptions: that the long-term body image incorporates the spatial characteristics of tools, and that it is distorted in the case of Alice in wonderland syndrome. Here, I challenge these assumptions, with a closer examination of what the term "long-term body image" refers to. In doing so, I draw out some important taxonomic principles for research into body representation.
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Affiliation(s)
- Stephen Gadsby
- Cognition and Philosophy Lab, Monash University, Melbourne, VIC 3800, Australia.
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27
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Miyazaki M, Asai T, Mugitani R. Touching! An Augmented Reality System for Unveiling Face Topography in Very Young Children. Front Hum Neurosci 2019; 13:189. [PMID: 31244628 PMCID: PMC6579857 DOI: 10.3389/fnhum.2019.00189] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Accepted: 05/22/2019] [Indexed: 11/22/2022] Open
Abstract
Developmental body topography, particularly of the face, is a fundamental research topic in the current decade. However, empirical investigation of this topic for very young children faces a number of difficulties related to the task requirements and technical procedures. In this study, we developed a new task to study the spatially-sensed position of facial parts in a self-face recognition task for 2.5- and 3.5-year-old children. Using the technique of augmented reality (AR) and 3D face tracking technology, we presented participants with their projected self-image on a screen, accompanied by a digital mark located on parts of their face. We prepared a cheerful visual and auditory reward on the screen when participants showed correct localization of the mark. We then tested whether they could indicate the position of the mark on their own faces and remain motivated for task repetition. To assess the efficacy of this task, 31 2.5- and 11 3.5-year-old children participated in this study. About half of the 2.5-year-olds and 80% of the 3.5-year-olds could perform more than 30 trials. Our new task, then, was to maintain young children’s motivation for task repetition using the cheerful visual and auditory reward. The analysis of localization errors suggested the uniqueness of spatial knowledge of self-face in young children. The efficacy of this new task for studying the development of body image has been confirmed.
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Affiliation(s)
- Michiko Miyazaki
- Department of Social Information Studies, Otsuma Women's University, Tokyo, Japan.,NTT Communication Science Laboratories, Atsugi, Japan
| | - Tomohisa Asai
- Advanced Telecommunications Research Institute International (ATR), Kyoto, Japan
| | - Ryoko Mugitani
- NTT Communication Science Laboratories, Atsugi, Japan.,The Faculty of Integrated Arts and Social Sciences, Japan Women's University, Kanagawa, Japan
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28
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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.
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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
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29
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Vittersø AD, Halicka M, Buckingham G, Proulx MJ, Bultitude JH. Experimentally induced pain does not influence updating of peripersonal space and body representations following tool-use. PLoS One 2019; 14:e0210045. [PMID: 31095562 PMCID: PMC6522125 DOI: 10.1371/journal.pone.0210045] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 05/07/2019] [Indexed: 12/16/2022] Open
Abstract
Representations of the body and peripersonal space can be distorted for people with some chronic pain conditions. Experimental pain induction can give rise to similar, but transient distortions in healthy individuals. However, spatial and bodily representations are dynamic, and constantly update as we interact with objects in our environment. It is unclear whether induced pain disrupts the mechanisms involved in updating these representations. In the present study, we sought to investigate the effect of induced pain on the updating of peripersonal space and body representations during and following tool-use. We compared performance under three conditions (pain, active placebo, neutral) on a visuotactile crossmodal congruency task and a tactile distance judgement task to measure updating of peripersonal space and body representations, respectively. Consistent with previous findings, the difference in crossmodal interference from visual distractors in the same compared to opposite visual field to the tactile target was less when tools were crossed than uncrossed. This suggests an extension of peripersonal space to incorporate the tips of the tools. Also consistent with previous findings, estimates of the felt tactile distance judgements decreased after active tool-use. In contrast to our predictions, however, we found no evidence that pain interfered with performance on either task when compared to the control conditions. Our findings suggest that the updating of peripersonal space and body representations is not disrupted by induced pain. That is, experiencing acute pain does not give rise to distorted representations of the body and peripersonal space that can be present in people with chronic pain conditions.
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Affiliation(s)
- Axel D Vittersø
- Centre for Pain Research, University of Bath, Bath, Somerset, United Kingdom.,Department of Psychology, University of Bath, Bath, Somerset, United Kingdom.,Department of Sport & Health Sciences, University of Exeter, Exeter, Devon, United Kingdom
| | - Monika Halicka
- Centre for Pain Research, University of Bath, Bath, Somerset, United Kingdom.,Department of Psychology, University of Bath, Bath, Somerset, United Kingdom
| | - Gavin Buckingham
- Department of Sport & Health Sciences, University of Exeter, Exeter, Devon, United Kingdom
| | - Michael J Proulx
- Department of Psychology, University of Bath, Bath, Somerset, United Kingdom.,Centre for Real and Virtual Environments Augmentation Labs, Department of Computer Science, University of Bath, Bath, Somerset, United Kingdom
| | - Janet H Bultitude
- Centre for Pain Research, University of Bath, Bath, Somerset, United Kingdom.,Department of Psychology, University of Bath, Bath, Somerset, United Kingdom
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30
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van der Veer AH, Longo MR, Alsmith AJT, Wong HY, Mohler BJ. Self and Body Part Localization in Virtual Reality: Comparing a Headset and a Large-Screen Immersive Display. Front Robot AI 2019; 6:33. [PMID: 33501049 PMCID: PMC7805778 DOI: 10.3389/frobt.2019.00033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 04/11/2019] [Indexed: 11/13/2022] Open
Abstract
It is currently not fully understood where people precisely locate themselves in their bodies, particularly in virtual reality. To investigate this, we asked participants to point directly at themselves and to several of their body parts with a virtual pointer, in two virtual reality (VR) setups, a VR headset and a large-screen immersive display (LSID). There was a difference in distance error in pointing to body parts depending on VR setup. Participants pointed relatively accurately to many of their body parts (i.e., eyes, nose, chin, shoulders, and waist). However, in both VR setups when pointing to the feet and the knees they pointed too low, and for the top of the head too high (to larger extents in the VR headset). Taking these distortions into account, the locations found for pointing to self were considered in terms of perceived bodies, based on where the participants had pointed to their body parts in the two VR setups. Pointing to self in terms of the perceived body was mostly to the face, the upper followed by the lower, as well as some to the torso regions. There was no significant overall effect of VR condition for pointing to self in terms of the perceived body (but there was a significant effect of VR if only the physical body (as measured) was considered). In a paper-and-pencil task outside of VR, performed by pointing on a picture of a simple body outline (body template task), participants pointed most to the upper torso. Possible explanations for the differences between pointing to self in the VR setups and the body template task are discussed. The main finding of this study is that the VR setup influences where people point to their body parts, but not to themselves, when perceived and not physical body parts are considered.
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Affiliation(s)
- Albert H. van der Veer
- Max Planck Institute for Biological Cybernetics, Tübingen, Germany
- International Max Planck Research School for Cognitive and Systems Neuroscience, University of Tübingen, Tübingen, Germany
| | - Matthew R. Longo
- Department of Psychological Sciences, Birkbeck, University of London, London, United Kingdom
| | | | - Hong Yu Wong
- Werner Reichardt Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
- Institute of Philosophy, Department of Philosophy and Media, University of Tübingen, Tübingen, Germany
| | - Betty J. Mohler
- Max Planck Institute for Biological Cybernetics, Tübingen, Germany
- Institute for Sport Science, Department of Human Sciences, Technical University of Darmstadt, Darmstadt, Germany
- Max Planck Institute for Intelligent Systems, Tübingen, Germany
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31
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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.
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32
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Tamè L, Azañón E, Longo MR. A Conceptual Model of Tactile Processing across Body Features of Size, Shape, Side, and Spatial Location. Front Psychol 2019; 10:291. [PMID: 30863333 PMCID: PMC6399380 DOI: 10.3389/fpsyg.2019.00291] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 01/29/2019] [Indexed: 11/30/2022] Open
Abstract
The processing of touch depends of multiple factors, such as the properties of the skin and type of receptors stimulated, as well as features related to the actual configuration and shape of the body itself. A large body of research has focused on the effect that the nature of the stimuli has on tactile processing. Less research, however, has focused on features beyond the nature of the touch. In this review, we focus on some features related to the body that have been investigated for less time and in a more fragmented way. These include the symmetrical quality of the two sides of the body, the postural configuration of the body, as well as the size and shape of different body parts. We will describe what we consider three key aspects: (1) how and at which stages tactile information is integrated between different parts and sides of the body; (2) how tactile signals are integrated with online and stored postural configurations of the body, regarded as priors; (3) and how tactile signals are integrated with representations of body size and shape. Here, we describe how these different body dimensions affect integration of tactile information as well as guide motor behavior by integrating them in a single model of tactile processing. We review a wide range of neuropsychological, neuroimaging, and neurophysiological data and suggest a revised model of tactile integration on the basis of the one proposed previously by Longo et al.
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Affiliation(s)
- Luigi Tamè
- Department of Psychological Sciences, Birkbeck University of London, London, United Kingdom.,School of Psychology, University of Kent, Canterbury, United Kingdom
| | - Elena Azañón
- Institute of Psychology, Otto von Guericke University Magdeburg, Magdeburg, Germany.,Center for Behavioral Brain Sciences, Magdeburg, Germany.,Department of Behavioral Neurology, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Matthew R Longo
- Department of Psychological Sciences, Birkbeck University of London, London, United Kingdom
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Corno G, Serino S, Cipresso P, Baños RM, Riva G. Assessing the Relationship Between Attitudinal and Perceptual Component of Body Image Disturbance Using Virtual Reality. CYBERPSYCHOLOGY BEHAVIOR AND SOCIAL NETWORKING 2019; 21:679-686. [PMID: 30421995 DOI: 10.1089/cyber.2018.0340] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Body image disturbance (BID) affects quality of life even in the absence of clinically diagnosable eating pathology, and numerous studies have shown its crucial role in the emergence and maintenance of eating disorders. This study aimed at exploring attitudinal and perceptual components of BID using a novel virtual reality (VR)-based paradigm. A community sample of women (N = 27) recreated in VR their perceived body in both an allocentric (third-person view) and egocentric (first-person view) perspective. Specifically, women were able to choose between a wide range of three-dimensional bodies spanning body mass index 12.5-42.5 kg/m2. Attitudinal indexes of BID (body dissatisfaction, body uneasiness, and body image avoidance) were assessed through questionnaires. Attitudinal components predicted the perceptual BID only in the allocentric perspective. Specifically, overestimation was predicted by body image avoidance, while underestimation was predicted by body uneasiness. Furthermore, a common predictor of underestimation and overestimation was body dissatisfaction. In line with the allocentric lock hypothesis, the current results seem to confirm the presence of two different mechanisms underlying BID: one related to real-time perception-driven inputs (egocentric frame) and one related to abstract knowledge, beliefs, and attitudes related to a person's body (allocentric frame). These findings contribute to a better understanding of the nature and mechanisms underlying BID and provide additional evidence about the suitability of using VR for exploring and assessing body image-related components and disturbances.
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Affiliation(s)
- Giulia Corno
- 1 Applied Technology for Neuro-Psychology Lab, I.R.C.C.S. Istituto Auxologico Italiano , Milan, Italy
| | - Silvia Serino
- 1 Applied Technology for Neuro-Psychology Lab, I.R.C.C.S. Istituto Auxologico Italiano , Milan, Italy .,2 Department of Psychology, Università Cattolica del Sacro Cuore , Milan, Italy
| | - Pietro Cipresso
- 1 Applied Technology for Neuro-Psychology Lab, I.R.C.C.S. Istituto Auxologico Italiano , Milan, Italy .,2 Department of Psychology, Università Cattolica del Sacro Cuore , Milan, Italy
| | - Rosa M Baños
- 3 Departamento Personalidad, Evaluación y Tratamientos Psicológicos, Universitat de Valencia , Valencia, Spain .,4 CIBER Pathophysiology of Obesity and Nutrition (CB06/03), Carlos III Institute of Health , Madrid, Spain
| | - Giuseppe Riva
- 1 Applied Technology for Neuro-Psychology Lab, I.R.C.C.S. Istituto Auxologico Italiano , Milan, Italy .,2 Department of Psychology, Università Cattolica del Sacro Cuore , Milan, Italy
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Sadibolova R, Ferrè ER, Linkenauger SA, Longo MR. Distortions of perceived volume and length of body parts. Cortex 2018; 111:74-86. [PMID: 30471452 DOI: 10.1016/j.cortex.2018.10.016] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Revised: 08/14/2018] [Accepted: 10/13/2018] [Indexed: 10/28/2022]
Abstract
We experience our body as a 3D, volumetric object in the world. Measures of our conscious body image, in contrast, have investigated the perception of body size along one or two dimensions at a time. There is, thus, a discrepancy between existing methods for measuring body image and our subjective experience of having 3D body. Here we assessed in a sample of healthy adults the perception of body size in terms of its 1D length and 3D volume. Participants were randomly assigned to two groups using different measuring units (other body part and non-body object). They estimated how many units would fit in a perceived size of body segments and the whole body. The patterns of length and volume misperception across judged segments were determined as their perceived size proportional to their actual size. The pattern of volume misperception paints the representation of 3D body proportions resembling those of a somatosensory homunculus. The body parts with a smaller actual surface area relative to their volume were underestimated more. There was a tendency for body parts underestimated in volume to be overestimated in length. Perceived body proportions thus changed as a function of judgement type while showing a similarity in magnitude of the absolute estimation error, be it an underestimation of volume or overestimation of length. The main contribution of this study is assessing the body image as a 3D body representation, and thus extending beyond the conventional 'allocentric' focus to include the body on the inside. Our findings highlight the value of studying the perceptual distortions "at the baseline", i.e., in healthy population, so as to advance the understanding of the nature of perceptual distortions in clinical conditions.
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Affiliation(s)
- Renata Sadibolova
- Department of Psychological Sciences, Birkbeck, University of London, United Kingdom.
| | - Elisa R Ferrè
- Department of Psychology, Royal Holloway, University of London, United Kingdom
| | | | - Matthew R Longo
- Department of Psychological Sciences, Birkbeck, University of London, United Kingdom
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Abstract
It is currently not well understood whether people experience themselves to be located in one or more specific part(s) of their body. Virtual reality (VR) is increasingly used as a tool to study aspects of bodily perception and self-consciousness, due to its strong experimental control and ease in manipulating multi-sensory aspects of bodily experience. To investigate where people self-locate in their body within virtual reality, we asked participants to point directly at themselves with a virtual pointer, in a VR headset. In previous work employing a physical pointer, participants mainly located themselves in the upper face and upper torso. In this study, using a VR headset, participants mainly located themselves in the upper face. In an additional body template task where participants pointed at themselves on a picture of a simple body outline, participants pointed most often to the upper torso, followed by the (upper) face. These results raise the question as to whether head-mounted virtual reality might alter where people locate themselves making them more "head-centred".
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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]
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37
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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]
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Sadibolova R, Tamè L, Walsh E, Longo MR. Mind the Gap: The Effects of Temporal and Spatial Separation in Localization of Dual Touches on the Hand. Front Hum Neurosci 2018; 12:55. [PMID: 29487518 PMCID: PMC5816905 DOI: 10.3389/fnhum.2018.00055] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 01/31/2018] [Indexed: 11/25/2022] Open
Abstract
In this study, we aimed to relate the findings from two predominantly separate streams of literature, one reporting on the localization of single touches on the skin, and the other on the distance perception of dual touches. Participants were touched with two points, delivered either simultaneously or separated by a short delay to various locations on their left hand dorsum. They then indicated on a size-matched hand silhouette the perceived locations of tactile stimuli. We quantified the deviations between the actual stimulus grid and the corresponding perceptual map which was constructed from the perceived tactile locations, and we calculated the precision of tactile localization (i.e., the variability across localization attempts). The evidence showed that the dual touches, akin to single touch stimulations, were mislocalized distally and that their variable localization error was reduced near joints, particularly near knuckles. However, contrary to single-touch localization literature, we observed for the dual touches to be mislocalized towards the ulnar side of the hand, particularly when they were presented sequentially. Further, the touches presented in a sequential order were slightly “repelled” from each other and their perceived distance increased, while the simultaneous tactile pairs were localized closer to each other and their distance was compressed. Whereas the sequential touches may have been localized with reference to the body, the compression of tactile perceptual space for simultaneous touches was related in the previous literature to signal summation and inhibition and the low-level factors, including the innervation density and properties of receptive fields (RFs) of somatosensory neurons.
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Affiliation(s)
- Renata Sadibolova
- Department of Psychological Sciences, Birkbeck, University of London, London, United Kingdom
| | - Luigi Tamè
- Department of Psychological Sciences, Birkbeck, University of London, London, United Kingdom
| | - Eamonn Walsh
- Department of Psychological Sciences, Birkbeck, University of London, London, United Kingdom.,Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London, United Kingdom
| | - Matthew R Longo
- Department of Psychological Sciences, Birkbeck, University of London, London, United Kingdom
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Abstract
Spatial illusions, such as the classic horizontal–vertical illusion, have played a major role in theories of visual organization. Although analogous illusions in touch have been known since the 19th century, they have been much less studied, and there is no general theory of their mechanistic basis. We developed and tested a model of tactile distance illusions in terms of a geometrically simple stretch of tactile space. We demonstrate that the pattern of perceived tactile distances across orientations is consistent with the model’s predictions. Similar results were apparent on the hand dorsum, palm, and forehead, suggesting it is a general characteristic of tactile spatial perception. These results show that tactile distance illusions reflect a geometrically simple deformation of tactile space. Illusions of the perception of distance between two touches on the skin have been described since the classic work of Weber in the 19th century. The perceptual mechanisms underlying such spatial distortions, however, remain poorly understood. One potential interpretation is that the representational space of touch is related to the true structure of the skin by a geometrically simple stretch. If distortions of tactile distance perception reflect a simple stretch of tactile space, perceived distance should vary predictably as a function of the orientation of the stimulus on the skin, showing a sinusoidal pattern. Here, we tested this prediction by obtained judgments of perceived tactile distance for pairs of touches aligned with eight orientations on the skin. Across four experiments, the results were highly consistent with this prediction, showing no apparent deviation from a model of simple stretch of tactile space. Similar results were apparent on both the dorsum and palm of the hand, as well as the forehead. These results show that spatial distortions of touch are well characterized by a geometrically simple stretch of tactile space.
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Abstract
Body image distortions are common in healthy individuals and a central aspect of serious clinical conditions, such as eating disorders. This commentary explores the potential implications of body image and its distortions for the insurance hypothesis. In particular, we speculate that body image may be an intervening variable mediating the relationship between perceived food scarcity and eating behavior.
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Abstract
A growing literature shows that body posture modulates the perception of touch, as well as somatosensory processing more widely. In this study, I investigated the effects of changes in the internal postural configuration of the hand on the perceived distance between touches. In two experiments participants positioned their hand in two postures, with the fingers splayed (Apart posture) or pressed together (Together posture). In Experiment 1, participants made forced-choice judgments of which of two tactile distances felt bigger, one oriented with the proximal-distal hand axis (Along orientation) and one oriented with the medio-lateral hand axis (Across orientation). In Experiment 2, participants made verbal estimates of the absolute distance between a single pair of touches, in one of the two orientations. Consistent with previous results, there was a clear bias to perceive distances in the across orientation as larger than those in the along orientation. Perceived tactile distance was also modulated by posture, with increased judgments in both orientations when the fingers were splayed. These results show that changes in the internal posture of the hand modulate the perceived distance between touches on the hand, and add to a growing literature showing postural modulation of touch.
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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.
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Affiliation(s)
- Matthew R Longo
- Department of Psychological Sciences, Birkbeck, University of London London, UK
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Longo MR, Morcom R. No Correlation between Distorted Body Representations Underlying Tactile Distance Perception and Position Sense. Front Hum Neurosci 2016; 10:593. [PMID: 27917118 PMCID: PMC5116574 DOI: 10.3389/fnhum.2016.00593] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 11/07/2016] [Indexed: 11/13/2022] Open
Abstract
Both tactile distance perception and position sense are believed to require that immediate afferent signals be referenced to a stored representation of body size and shape (the body model). For both of these abilities, recent studies have reported that the stored body representations involved are highly distorted, at least in the case of the hand, with the hand dorsum represented as wider and squatter than it actually is. Here, we investigated whether individual differences in the magnitude of these distortions are shared between tactile distance perception and position sense, as would be predicted by the hypothesis that a single distorted body model underlies both tasks. We used established tasks to measure distortions of the represented shape of the hand dorsum. Consistent with previous results, in both cases there were clear biases to overestimate distances oriented along the medio-lateral axis of the hand compared to the proximo-distal axis. Moreover, within each task there were clear split-half correlations, demonstrating that both tasks show consistent individual differences. Critically, however, there was no correlation between the magnitudes of distortion in the two tasks. This casts doubt on the proposal that a common body model underlies both tactile distance perception and position sense.
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Affiliation(s)
- Matthew R Longo
- Department of Psychological Sciences, Birkbeck, University of London London, UK
| | - Rosa Morcom
- Department of Psychological Sciences, Birkbeck, University of London London, UK
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Luongo MA, Pazzaglia M. Commentary: Body Image Distortion and Exposure to Extreme Body Types: Contingent Adaptation and Cross Adaptation for Self and Other. Front Hum Neurosci 2016; 10:526. [PMID: 27818630 PMCID: PMC5073138 DOI: 10.3389/fnhum.2016.00526] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 10/04/2016] [Indexed: 11/13/2022] Open
Affiliation(s)
| | - Mariella Pazzaglia
- Department of Psychology, University of Rome “La Sapienza”Rome, Italy
- Clinical Neuroscience Lab, IRCCS Santa Lucia FoundationRome, Italy
- *Correspondence: Mariella Pazzaglia
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Pazzaglia M, Zantedeschi M. Plasticity and Awareness of Bodily Distortion. Neural Plast 2016; 2016:9834340. [PMID: 27630779 PMCID: PMC5007354 DOI: 10.1155/2016/9834340] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 07/20/2016] [Accepted: 08/01/2016] [Indexed: 12/26/2022] Open
Abstract
Knowledge of the body is filtered by perceptual information, recalibrated through predominantly innate stored information, and neurally mediated by direct sensory motor information. Despite multiple sources, the immediate prediction, construction, and evaluation of one's body are distorted. The origins of such distortions are unclear. In this review, we consider three possible sources of awareness that inform body distortion. First, the precision in the body metric may be based on the sight and positioning sense of a particular body segment. This view provides information on the dual nature of body representation, the reliability of a conscious body image, and implicit alterations in the metrics and positional correspondence of body parts. Second, body awareness may reflect an innate organizational experience of unity and continuity in the brain, with no strong isomorphism to body morphology. Third, body awareness may be based on efferent/afferent neural signals, suggesting that major body distortions may result from changes in neural sensorimotor experiences. All these views can be supported empirically, suggesting that body awareness is synthesized from multimodal integration and the temporal constancy of multiple body representations. For each of these views, we briefly discuss abnormalities and therapeutic strategies for correcting the bodily distortions in various clinical disorders.
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Affiliation(s)
- Mariella Pazzaglia
- Department of Psychology, University of Rome “La Sapienza,” Via dei Marsi 78, 00185 Rome, Italy
- IRCCS Santa Lucia Foundation, Via Ardeatina 306, 00179 Rome, Italy
| | - Marta Zantedeschi
- Department of Psychology, University of Rome “La Sapienza,” Via dei Marsi 78, 00185 Rome, Italy
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