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Heldmann M, Spitta G, Wagner-Altendorf T, Münte TF. Threatening an Illusory Limb: An Event-related Potential Study of the Rubber Hand Illusion. Cogn Behav Neurol 2024:00146965-990000000-00069. [PMID: 39056214 DOI: 10.1097/wnn.0000000000000372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2023] [Accepted: 03/04/2024] [Indexed: 07/28/2024]
Abstract
BACKGROUND The rubber hand illusion (RHI) is a well-established method for studying body ownership: Given adequate concordance of visual, sensory, and proprioceptive stimuli, the individual experiences a rubber hand as his or her own. OBJECTIVE To study the effects of a threat to the rubber hand. METHODS We created a typical RHI paradigm but added threatening pain: Both the real hand of an individual and the rubber hand were stroked with a brush, either synchronously (RHI-inducing condition) or asynchronously (control condition), but only the rubber hand was then pricked with a needle to create a threatening pain condition. Event-related potentials (ERPs) were recorded in a group of 23 typically developed individuals. ERP effects were source-localized using low-resolution electromagnetic tomography. RESULTS The individuals consistently reported experience of the RHI during the experiment when the brush strokes were applied synchronously to both the real hand and the rubber hand. ERP analysis revealed that synchronous brush stroking gave rise to higher amplitude of frontal ERPs in the 100-200 ms range than asynchronous brush stroking, which was interpreted as reflecting the RHI. In the threatening pain condition, ERPs showed a greater positivity at frontocentral electrodes, source localized in the supplementary motor area (SMA). CONCLUSION SMA activation could reflect a control mechanism over reflexive motor activity, facilitating a possible threat-related response. Further studies should address ERP effects and the extent of the RHI to standard and threat stimuli in a correlative fashion to further elucidate the functional significance of the neurophysiological findings.
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Affiliation(s)
- Marcus Heldmann
- Department of Neurology, University of Lübeck, Lübeck, Germany
- Center for Brain Behavior and Metabolism, University of Lübeck, Lübeck, Germany
| | - Gregor Spitta
- Department of Neurology, University of Lübeck, Lübeck, Germany
| | - Tobias Wagner-Altendorf
- Department of Neurology, University of Lübeck, Lübeck, Germany
- Center for Brain Behavior and Metabolism, University of Lübeck, Lübeck, Germany
| | - Thomas F Münte
- Center for Brain Behavior and Metabolism, University of Lübeck, Lübeck, Germany
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2
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Cirillo E, Zavattaro C, Gammeri R, Serra H, Ricci R, Berti A. Have I Been Touched? Subjective and Objective Aspects of Tactile Awareness. Brain Sci 2024; 14:653. [PMID: 39061394 PMCID: PMC11274638 DOI: 10.3390/brainsci14070653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2024] [Revised: 06/19/2024] [Accepted: 06/26/2024] [Indexed: 07/28/2024] Open
Abstract
Somatosensory tactile experience is a key aspect of our interaction with the environment. It is involved in object manipulation, in the planning and control of actions and, in its affective components, in the relationships with other individuals. It is also a foundational component of body awareness. An intriguing aspect of sensory perception in general and tactile perception in particular is the way in which stimulation comes to consciousness. Indeed, although being aware of something seems a rather self-evident and monolithic aspect of our mental states, sensory awareness may be in fact modulated by many different processes that impact on the mere stimulation of the skin, including the way in which we perceive our bodies as belonging to us. In this review, we first took into consideration the pathological conditions of absence of phenomenal experience of touch, in the presence of implicit processing, as initial models for understanding the neural bases of conscious tactile experience. Subsequently, we discussed cases of tactile illusions both in normal subjects and in brain-damaged patients which help to understand which high-order processes impact tactile awareness. Finally, we discussed the observations reported in the review in light of some influential models of touch and body representation.
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Affiliation(s)
| | | | | | | | | | - Anna Berti
- Department of Psychology, University of Turin, Via Verdi 10, 10124 Turin, Italy; (E.C.); (C.Z.); (R.G.); (H.S.); (R.R.)
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3
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Magnani FG, Cacciatore M, Barbadoro F, Ippoliti C, Leonardi M. Sense of ownership influence on tactile perception: Is the predictive coding account valid for the somatic rubber hand Illusion? Conscious Cogn 2024; 123:103710. [PMID: 38870729 DOI: 10.1016/j.concog.2024.103710] [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: 02/19/2024] [Revised: 05/08/2024] [Accepted: 06/04/2024] [Indexed: 06/15/2024]
Abstract
According to the predictive coding account, the attenuation of tactile perception on the hand exposed to the visuo-tactile Rubber Hand Illusion (vtRHI) relies on a weight increase of visual information deriving from the fake hand and a weight decrease of tactile information deriving from the individual's hand. To explore if this diametrical modulation persists in the absence of vision when adopting the somatic RHI (sRHI), we recorded tactile acuity measures before and after both RHI paradigms in 31 healthy individuals, hypothesizing a weight decrease for somatosensory information deriving from the hand undergoing the illusion and a weight increase for those deriving from the contralateral hand in the sRHI. Our results showed a significant overall decrease in tactile acuity on the hand undergoing the illusion whilst no changes emerged on the contralateral hand during sRHI. Since the sRHI was not accompanied by the hand spatial remapping, despite the generation of the feeling of ownership toward the fake hand, we hypothesized spatial remapping might play a pivotal role in determining sensory information weight attribution.
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Affiliation(s)
- Francesca G Magnani
- SC Neurologia, Salute Pubblica, Disabilità - Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Martina Cacciatore
- SC Neurologia, Salute Pubblica, Disabilità - Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy.
| | - Filippo Barbadoro
- SC Neurologia, Salute Pubblica, Disabilità - Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Camilla Ippoliti
- SC Neurologia, Salute Pubblica, Disabilità - Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Matilde Leonardi
- SC Neurologia, Salute Pubblica, Disabilità - Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
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4
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Rossi Sebastiano A, Poles K, Gualtiero S, Romeo M, Galigani M, Bruno V, Fossataro C, Garbarini F. Balancing the Senses: Electrophysiological Responses Reveal the Interplay between Somatosensory and Visual Processing During Body-Related Multisensory Conflict. J Neurosci 2024; 44:e1397232024. [PMID: 38508711 PMCID: PMC11079966 DOI: 10.1523/jneurosci.1397-23.2024] [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: 07/24/2023] [Revised: 12/27/2023] [Accepted: 01/03/2024] [Indexed: 03/22/2024] Open
Abstract
In the study of bodily awareness, the predictive coding theory has revealed that our brain continuously modulates sensory experiences to integrate them into a unitary body representation. Indeed, during multisensory illusions (e.g., the rubber hand illusion, RHI), the synchronous stroking of the participant's concealed hand and a fake visible one creates a visuotactile conflict, generating a prediction error. Within the predictive coding framework, through sensory processing modulation, prediction errors are solved, inducing participants to feel as if touches originated from the fake hand, thus ascribing the fake hand to their own body. Here, we aimed to address sensory processing modulation under multisensory conflict, by disentangling somatosensory and visual stimuli processing that are intrinsically associated during the illusion induction. To this aim, we designed two EEG experiments, in which somatosensory- (SEPs; Experiment 1; N = 18; F = 10) and visual-evoked potentials (VEPs; Experiment 2; N = 18; F = 9) were recorded in human males and females following the RHI. Our results show that, in both experiments, ERP amplitude is significantly modulated in the illusion as compared with both control and baseline conditions, with a modality-dependent diametrical pattern showing decreased SEP amplitude and increased VEP amplitude. Importantly, both somatosensory and visual modulations occur in long-latency time windows previously associated with tactile and visual awareness, thus explaining the illusion of perceiving touch at the sight location. In conclusion, we describe a diametrical modulation of somatosensory and visual processing as the neural mechanism that allows maintaining a stable body representation, by restoring visuotactile congruency under the occurrence of multisensory conflicts.
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Affiliation(s)
| | - Karol Poles
- MANIBUS Lab, Psychology Department, University of Turin, Turin 10124, Italy
| | - Stefano Gualtiero
- MANIBUS Lab, Psychology Department, University of Turin, Turin 10124, Italy
| | - Marcella Romeo
- MANIBUS Lab, Psychology Department, University of Turin, Turin 10124, Italy
- IMT School for Advanced Studies Lucca, Lucca 55100, Italy
| | - Mattia Galigani
- MANIBUS Lab, Psychology Department, University of Turin, Turin 10124, Italy
| | - Valentina Bruno
- MANIBUS Lab, Psychology Department, University of Turin, Turin 10124, Italy
| | - Carlotta Fossataro
- MANIBUS Lab, Psychology Department, University of Turin, Turin 10124, Italy
| | - Francesca Garbarini
- MANIBUS Lab, Psychology Department, University of Turin, Turin 10124, Italy
- Neuroscience Institute of Turin (NIT), Turin 10124, Italy
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5
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Castro F, Lenggenhager B, Zeller D, Pellegrino G, D'Alonzo M, Di Pino G. From rubber hands to neuroprosthetics: Neural correlates of embodiment. Neurosci Biobehav Rev 2023; 153:105351. [PMID: 37544389 PMCID: PMC10582798 DOI: 10.1016/j.neubiorev.2023.105351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Revised: 07/10/2023] [Accepted: 08/03/2023] [Indexed: 08/08/2023]
Abstract
Our interaction with the world rests on the knowledge that we are a body in space and time, which can interact with the environment. This awareness is usually referred to as sense of embodiment. For the good part of the past 30 years, the rubber hand illusion (RHI) has been a prime tool to study embodiment in healthy and people with a variety of clinical conditions. In this paper, we provide a critical overview of this research with a focus on the RHI paradigm as a tool to study prothesis embodiment in individuals with amputation. The RHI relies on well-documented multisensory integration mechanisms based on sensory precision, where parietal areas are involved in resolving the visuo-tactile conflict, and premotor areas in updating the conscious bodily representation. This mechanism may be transferable to prosthesis ownership in amputees. We discuss how these results might transfer to technological development of sensorised prostheses, which in turn might progress the acceptability by users.
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Affiliation(s)
- Fabio Castro
- Neurophysiology and Neuroengineering of Human-Technology Interaction Research Unit, Campus Bio-Medico University, via Alvaro del Portillo 5, 00128 Rome, Italy; Institute of Sport, School of Life and Medical Sciences, University of Hertfordshire, Hatfield, United Kingdom
| | - Bigna Lenggenhager
- Department of Psychology, Cognitive Psychology, University of Konstanz, Universitätsstraße 10, 78464 Konstanz, Germany; Department of Psychology, University of Zurich, Binzmuehlestrasse 14, 8050 Zurich, Switzerland
| | - Daniel Zeller
- Department of Neurology, University Hospital Würzburg, Josef-Schneider-Str. 11, 97080 Würzburg, Germany
| | - Giovanni Pellegrino
- Epilepsy program, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Marco D'Alonzo
- Neurophysiology and Neuroengineering of Human-Technology Interaction Research Unit, Campus Bio-Medico University, via Alvaro del Portillo 5, 00128 Rome, Italy.
| | - Giovanni Di Pino
- Neurophysiology and Neuroengineering of Human-Technology Interaction Research Unit, Campus Bio-Medico University, via Alvaro del Portillo 5, 00128 Rome, Italy
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6
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Corcoran AW, Perrykkad K, Feuerriegel D, Robinson JE. Body as First Teacher: The Role of Rhythmic Visceral Dynamics in Early Cognitive Development. PERSPECTIVES ON PSYCHOLOGICAL SCIENCE 2023:17456916231185343. [PMID: 37694720 DOI: 10.1177/17456916231185343] [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: 09/12/2023]
Abstract
Embodied cognition-the idea that mental states and processes should be understood in relation to one's bodily constitution and interactions with the world-remains a controversial topic within cognitive science. Recently, however, increasing interest in predictive processing theories among proponents and critics of embodiment alike has raised hopes of a reconciliation. This article sets out to appraise the unificatory potential of predictive processing, focusing in particular on embodied formulations of active inference. Our analysis suggests that most active-inference accounts invoke weak, potentially trivial conceptions of embodiment; those making stronger claims do so independently of the theoretical commitments of the active-inference framework. We argue that a more compelling version of embodied active inference can be motivated by adopting a diachronic perspective on the way rhythmic physiological activity shapes neural development in utero. According to this visceral afferent training hypothesis, early-emerging physiological processes are essential not only for supporting the biophysical development of neural structures but also for configuring the cognitive architecture those structures entail. Focusing in particular on the cardiovascular system, we propose three candidate mechanisms through which visceral afferent training might operate: (a) activity-dependent neuronal development, (b) periodic signal modeling, and (c) oscillatory network coordination.
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Affiliation(s)
- Andrew W Corcoran
- Monash Centre for Consciousness and Contemplative Studies, Monash University
- Cognition and Philosophy Laboratory, School of Philosophical, Historical, and International Studies, Monash University
| | - Kelsey Perrykkad
- Cognition and Philosophy Laboratory, School of Philosophical, Historical, and International Studies, Monash University
| | | | - Jonathan E Robinson
- Cognition and Philosophy Laboratory, School of Philosophical, Historical, and International Studies, Monash University
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7
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Shibuya S, Ohki Y. Mu Rhythm Desynchronization while Observing Rubber Hand Movement in the Mirror: The Interaction of Body Representation with Visuo-Tactile Stimulation. Brain Sci 2023; 13:969. [PMID: 37371446 DOI: 10.3390/brainsci13060969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 06/16/2023] [Accepted: 06/16/2023] [Indexed: 06/29/2023] Open
Abstract
During rubber hand illusion (RHI), participants feel that a rubber (fake) hand is their own (i.e., embodiment of the rubber hand) if the unseen real hand and seen rubber hand are stroked synchronously (i.e., visuo-tactile stimuli). The RHI is also evoked if the real and rubber hands are placed in the same position (i.e., visual-proprioceptive congruency), which can be performed using a mirror setting. Using electroencephalography (EEG) and mirror settings, we compared μ rhythm (8-13 Hz) event-related desynchronization (ERD; an index of sensorimotor activation) while watching the movements of embodied or non-embodied rubber hands, which was preceded by an observation of the rubber hand with or without synchronous visuo-tactile stimuli. The illusory ownership of the fake hand was manipulated using visual continuity with (RHI) and without (non-RHI) a fake forearm. Resultantly, an ownership-dependent μ rhythm ERD was found when delivering visuo-tactile stimuli; a greater and more persistent μ rhythm ERD during the rubber hand movement was identified in the RHI in comparison to the non-RHI condition. However, no difference was observed between the two when observing the fake hand alone. These findings suggest the possibility that a self-related multisensory interaction between body representation (top-down processing) and visuo-tactile inputs (bottom-up processing) before a fake hand movement produces ownership-dependent sensorimotor activations during subsequent movement observations.
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Affiliation(s)
- Satoshi Shibuya
- Department of Integrative Physiology, School of Medicine, Kyorin University, Tokyo 181-8611, Japan
| | - Yukari Ohki
- Department of Integrative Physiology, School of Medicine, Kyorin University, Tokyo 181-8611, Japan
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8
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De Ridder D, Friston K, Sedley W, Vanneste S. A parahippocampal-sensory Bayesian vicious circle generates pain or tinnitus: a source-localized EEG study. Brain Commun 2023; 5:fcad132. [PMID: 37223127 PMCID: PMC10202557 DOI: 10.1093/braincomms/fcad132] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 02/14/2023] [Accepted: 04/19/2023] [Indexed: 05/25/2023] Open
Abstract
Pain and tinnitus share common pathophysiological mechanisms, clinical features, and treatment approaches. A source-localized resting-state EEG study was conducted in 150 participants: 50 healthy controls, 50 pain, and 50 tinnitus patients. Resting-state activity as well as functional and effective connectivity was computed in source space. Pain and tinnitus were characterized by increased theta activity in the pregenual anterior cingulate cortex, extending to the lateral prefrontal cortex and medial anterior temporal lobe. Gamma-band activity was increased in both auditory and somatosensory cortex, irrespective of the pathology, and extended to the dorsal anterior cingulate cortex and parahippocampus. Functional and effective connectivity were largely similar in pain and tinnitus, except for a parahippocampal-sensory loop that distinguished pain from tinnitus. In tinnitus, the effective connectivity between parahippocampus and auditory cortex is bidirectional, whereas the effective connectivity between parahippocampus and somatosensory cortex is unidirectional. In pain, the parahippocampal-somatosensory cortex is bidirectional, but parahippocampal auditory cortex unidirectional. These modality-specific loops exhibited theta-gamma nesting. Applying a Bayesian brain model of brain functioning, these findings suggest that the phenomenological difference between auditory and somatosensory phantom percepts result from a vicious circle of belief updating in the context of missing sensory information. This finding may further our understanding of multisensory integration and speaks to a universal treatment for pain and tinnitus-by selectively disrupting parahippocampal-somatosensory and parahippocampal-auditory theta-gamma activity and connectivity.
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Affiliation(s)
- Dirk De Ridder
- Unit of Neurosurgery, Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin 9016, New Zealand
| | - Karl Friston
- Wellcome Trust Centre for Neuroimaging, University College London, London WC1N 3AR, UK
| | - William Sedley
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Sven Vanneste
- Correspondence to: Sven Vanneste Lab for Clinical & Integrative Neuroscience Global Brain Health Institute and Institute of Neuroscience Trinity College Dublin, College Green 2, Dublin D02 PN40, Ireland E-mail:
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9
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Abdulkarim Z, Guterstam A, Hayatou Z, Ehrsson HH. Neural Substrates of Body Ownership and Agency during Voluntary Movement. J Neurosci 2023; 43:2362-2380. [PMID: 36801824 PMCID: PMC10072298 DOI: 10.1523/jneurosci.1492-22.2023] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 01/18/2023] [Accepted: 02/12/2023] [Indexed: 02/19/2023] Open
Abstract
Body ownership and the sense of agency are two central aspects of bodily self-consciousness. While multiple neuroimaging studies have investigated the neural correlates of body ownership and agency separately, few studies have investigated the relationship between these two aspects during voluntary movement when such experiences naturally combine. By eliciting the moving rubber hand illusion with active or passive finger movements during functional magnetic resonance imaging, we isolated activations reflecting the sense of body ownership and agency, respectively, as well as their interaction, and assessed their overlap and anatomic segregation. We found that perceived hand ownership was associated with activity in premotor, posterior parietal, and cerebellar regions, whereas the sense of agency over the movements of the hand was related to activity in the dorsal premotor cortex and superior temporal cortex. Moreover, one section of the dorsal premotor cortex showed overlapping activity for ownership and agency, and somatosensory cortical activity reflected the interaction of ownership and agency with higher activity when both agency and ownership were experienced. We further found that activations previously attributed to agency in the left insular cortex and right temporoparietal junction reflected the synchrony or asynchrony of visuoproprioceptive stimuli rather than agency. Collectively, these results reveal the neural bases of agency and ownership during voluntary movement. Although the neural representations of these two experiences are largely distinct, there are interactions and functional neuroanatomical overlap during their combination, which has bearing on theories on bodily self-consciousness.SIGNIFICANCE STATEMENT How does the brain generate the sense of being in control of bodily movement (agency) and the sense that body parts belong to one's body (body ownership)? Using fMRI and a bodily illusion triggered by movement, we found that agency is associated with activity in premotor cortex and temporal cortex, and body ownership with activity in premotor, posterior parietal, and cerebellar regions. The activations reflecting the two sensations were largely distinct, but there was overlap in premotor cortex and an interaction in somatosensory cortex. These findings advance our understanding of the neural bases of and interplay between agency and body ownership during voluntary movement, which has implications for the development of advanced controllable prosthetic limbs that feel like real limbs.
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Affiliation(s)
| | - Arvid Guterstam
- Department of Clinical Neuroscience, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Zineb Hayatou
- Université Paris-Saclay, CNRS, Institut Des Neurosciences Paris-Saclay, 91190 Gif-sur-Yvette, France
| | - H Henrik Ehrsson
- Department of Neuroscience, Karolinska Institutet, 171 77 Stockholm, Sweden
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10
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Marguilho M, Figueiredo I, Castro-Rodrigues P. A unified model of ketamine's dissociative and psychedelic properties. J Psychopharmacol 2023; 37:14-32. [PMID: 36527355 PMCID: PMC9834329 DOI: 10.1177/02698811221140011] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Ketamine is an N-methyl-d-aspartate antagonist which is increasingly being researched and used as a treatment for depression. In low doses, it can cause a transitory modification in consciousness which was classically labelled as 'dissociation'. However, ketamine is also commonly classified as an atypical psychedelic and it has been recently reported that ego dissolution experiences during ketamine administration are associated with greater antidepressant response. Neuroimaging studies have highlighted several similarities between the effects of ketamine and those of serotonergic psychedelics in the brain; however, no unified account has been proposed for ketamine's multi-level effects - from molecular to network and psychological levels. Here, we propose that the fast, albeit transient, antidepressant effects observed after ketamine infusions are mainly driven by its acute modulation of reward circuits and sub-acute increase in neuroplasticity, while its dissociative and psychedelic properties are driven by dose- and context-dependent disruption of large-scale functional networks. Computationally, as nodes of the salience network (SN) represent high-level priors about the body ('minimal' self) and nodes of the default-mode network (DMN) represent the highest-level priors about narrative self-experience ('biographical' self), we propose that transitory SN desegregation and disintegration accounts for ketamine's 'dissociative' state, while transitory DMN desegregation and disintegration accounts for ketamine's 'psychedelic' state. In psychedelic-assisted psychotherapy, a relaxation of the highest-level beliefs with psychotherapeutic support may allow a revision of pathological self-representation models, for which neuroplasticity plays a permissive role. Our account provides a multi-level rationale for using the psychedelic properties of ketamine to increase its long-term benefits.
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Affiliation(s)
| | | | - Pedro Castro-Rodrigues
- Centro Hospitalar Psiquiátrico de Lisboa, Lisbon, Portugal,NOVA Medical School, NMS, Universidade Nova de Lisboa, Lisbon, Portugal,Pedro Castro-Rodrigues, Centro Hospitalar Psiquiátrico de Lisboa, Avenida do Brasil, 53, Lisbon, 1749-002, Portugal.
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11
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Hybart RL, Ferris DP. Embodiment for Robotic Lower-Limb Exoskeletons: A Narrative Review. IEEE Trans Neural Syst Rehabil Eng 2022; PP:10.1109/TNSRE.2022.3229563. [PMID: 37015690 PMCID: PMC10267288 DOI: 10.1109/tnsre.2022.3229563] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Research on embodiment of objects external to the human body has revealed important information about how the human nervous system interacts with robotic lower limb exoskeletons. Typical robotic exoskeleton control approaches view the controllers as an external agent intending to move in coordination with the human. However, principles of embodiment suggest that the exoskeleton controller should ideally coordinate with the human such that the nervous system can adequately model the input-output dynamics of the exoskeleton controller. Measuring embodiment of exoskeletons should be a necessary step in the exoskeleton development and prototyping process. Researchers need to establish high fidelity quantitative measures of embodiment, rather than relying on current qualitative survey measures. Mobile brain imaging techniques, such as high-density electroencephalography, is likely to provide a deeper understanding of embodiment during human-machine interactions and advance exoskeleton research and development. In this review we show why future exoskeleton research should include quantitative measures of embodiment as a metric of success.
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12
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Shibuya S, Oosone H, Ohki Y. Tactile temporal order judgment during rubber hand illusion: Distinct modulation of the point of subjective simultaneity and temporal resolution. Conscious Cogn 2022; 105:103402. [PMID: 36067686 DOI: 10.1016/j.concog.2022.103402] [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: 04/08/2022] [Revised: 08/10/2022] [Accepted: 08/24/2022] [Indexed: 01/27/2023]
Abstract
During the rubber hand illusion (RHI), individuals feel a fake hand as their own (ownership) and a perceived position of their real hand shifts toward the fake hand (proprioceptive drift; PD), which represents updating of multisensory hand representations. Bimanual tactile temporal order judgment (TOJ) includes processes of localizing tactile stimuli in space, for which multisensory hand representations are essential. According to the common processes, we examined tactile TOJ performance during the RHI and non-RHI. Temporal resolution (TR) as TOJ accuracy worsened during the non-RHI compared to the RHI. Additionally, a significant correlation between TR and PD was observed only in the non-RHI condition. However, the point of subjective simultaneity (PSS), which offers relative weighting of tactile inputs from the right and left hands, was correlated with illusory hand ownership. These results suggest that PSS and TR from tactile TOJ during RHI relate to self-attribution and localization of the hand, respectively.
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Affiliation(s)
- Satoshi Shibuya
- Department of Integrative Physiology, School of Medicine, Kyorin University, 6-20-2 Shinkawa, Mitaka, Tokyo 181-8611, Japan.
| | - Hiroki Oosone
- Chiba Minato Rehabilitation Hospital, 1-17-18 Chuo-minato, Chuo-ku, Chiba City, Chiba 260-0024, Japan
| | - Yukari Ohki
- Department of Integrative Physiology, School of Medicine, Kyorin University, 6-20-2 Shinkawa, Mitaka, Tokyo 181-8611, Japan
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13
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Sciortino P, Kayser C. The rubber hand illusion is accompanied by a distributed reduction of alpha and beta power in the EEG. PLoS One 2022; 17:e0271659. [PMID: 35905100 PMCID: PMC9337658 DOI: 10.1371/journal.pone.0271659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 07/05/2022] [Indexed: 11/18/2022] Open
Abstract
Previous studies have reported correlates of bodily self-illusions such as the rubber hand in signatures of rhythmic brain activity. However, individual studies focused on specific variations of the rubber hand paradigm, used different experimental setups to induce this, or used different control conditions to isolate the neurophysiological signatures related to the illusory state, leaving the specificity of the reported illusion-signatures unclear. We here quantified correlates of the rubber hand illusion in EEG-derived oscillatory brain activity and asked two questions: which of the observed correlates are robust to the precise nature of the control conditions used as contrast for the illusory state, and whether such correlates emerge directly around the subjective illusion onset. To address these questions, we relied on two experimental configurations to induce the illusion, on different non-illusion conditions to isolate neurophysiological signatures of the illusory state, and we implemented an analysis directly focusing on the immediate moment of the illusion onset. Our results reveal a widespread suppression of alpha and beta-band activity associated with the illusory state in general, whereby the reduction of beta power prevailed around the immediate illusion onset. These results confirm previous reports of a suppression of alpha and beta rhythms during body illusions, but also highlight the difficulties to directly pinpoint the precise neurophysiological correlates of the illusory state.
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Affiliation(s)
- Placido Sciortino
- Department of Cognitive Neuroscience, Faculty of Biology, Bielefeld University, Bielefeld, Germany
- * E-mail:
| | - Christoph Kayser
- Department of Cognitive Neuroscience, Faculty of Biology, Bielefeld University, Bielefeld, Germany
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14
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Bouziane I, Das M, Friston KJ, Caballero-Gaudes C, Ray D. Enhanced top-down sensorimotor processing in somatic anxiety. Transl Psychiatry 2022; 12:295. [PMID: 35879273 PMCID: PMC9314421 DOI: 10.1038/s41398-022-02061-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 06/28/2022] [Accepted: 07/05/2022] [Indexed: 11/10/2022] Open
Abstract
Functional neuroimaging research on anxiety has traditionally focused on brain networks associated with the psychological aspects of anxiety. Here, instead, we target the somatic aspects of anxiety. Motivated by the growing appreciation that top-down cortical processing plays a crucial role in perception and action, we used resting-state functional MRI data from the Human Connectome Project and Dynamic Causal Modeling (DCM) to characterize effective connectivity among hierarchically organized regions in the exteroceptive, interoceptive, and motor cortices. In people with high (fear-related) somatic arousal, top-down effective connectivity was enhanced in all three networks: an observation that corroborates well with the phenomenology of anxiety. The anxiety-associated changes in connectivity were sufficiently reliable to predict whether a new participant has mild or severe somatic anxiety. Interestingly, the increase in top-down connections to sensorimotor cortex were not associated with fear affect scores, thus establishing the (relative) dissociation between somatic and cognitive dimensions of anxiety. Overall, enhanced top-down effective connectivity in sensorimotor cortices emerges as a promising and quantifiable candidate marker of trait somatic anxiety.
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Affiliation(s)
- Ismail Bouziane
- grid.423986.20000 0004 0536 1366Basque Center on Cognition, Brain and Language, San Sebastian, Spain ,grid.11480.3c0000000121671098University of the Basque Country, San Sebastian, Spain
| | - Moumita Das
- grid.462072.50000 0004 0467 2410Basque Center for Applied Mathematics, Bilbao, Spain
| | - Karl J. Friston
- grid.450002.30000 0004 0611 8165Wellcome Centre for Human Neuroimaging, London, UK ,grid.83440.3b0000000121901201Queen Square Institute of Neurology, University College London, London, UK ,grid.436283.80000 0004 0612 2631The National Hospital for Neurology and Neurosurgery, London, UK
| | - Cesar Caballero-Gaudes
- grid.423986.20000 0004 0536 1366Basque Center on Cognition, Brain and Language, San Sebastian, Spain
| | - Dipanjan Ray
- Basque Center on Cognition, Brain and Language, San Sebastian, Spain.
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15
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Ciaunica A, Seth A, Limanowski J, Hesp C, Friston KJ. I overthink—Therefore I am not: An active inference account of altered sense of self and agency in depersonalisation disorder. Conscious Cogn 2022; 101:103320. [PMID: 35490544 PMCID: PMC9130736 DOI: 10.1016/j.concog.2022.103320] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 03/27/2022] [Accepted: 03/29/2022] [Indexed: 12/17/2022]
Abstract
This paper examines potential mechanisms behind atypical sense of self and agency in Depersonalisation Disorder (DPD). Using Active Inference, we argue that aberrant somatosensory attenuation and precision weighting underlies DPD. Failures of somatosensory attenuation may disrupt the sense of agency and control over one’s perceptions and actions. In DPD, individuals may believe ‘another agent’ is controlling their thoughts, perceptions or actions. Unlike psychosis however, in DPD the individual maintains the full insight that the ‘other agent’ is ‘me’ (the self).
This paper considers the phenomenology of depersonalisation disorder, in relation to predictive processing and its associated pathophysiology. To do this, we first establish a few mechanistic tenets of predictive processing that are necessary to talk about phenomenal transparency, mental action, and self as subject. We briefly review the important role of ‘predicting precision’ and how this affords mental action and the loss of phenomenal transparency. We then turn to sensory attenuation and the phenomenal consequences of (pathophysiological) failures to attenuate or modulate sensory precision. We then consider this failure in the context of depersonalisation disorder. The key idea here is that depersonalisation disorder reflects the remarkable capacity to explain perceptual engagement with the world via the hypothesis that “I am an embodied perceiver, but I am not in control of my perception”. We suggest that individuals with depersonalisation may believe that ‘another agent’ is controlling their thoughts, perceptions or actions, while maintaining full insight that the ‘other agent’ is ‘me’ (the self). Finally, we rehearse the predictions of this formal analysis, with a special focus on the psychophysical and physiological abnormalities that may underwrite the phenomenology of depersonalisation.
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16
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Hsu TY, Zhou JF, Yeh SL, Northoff G, Lane TJ. Intrinsic neural activity predisposes susceptibility to a body illusion. Cereb Cortex Commun 2022; 3:tgac012. [PMID: 35382092 PMCID: PMC8976633 DOI: 10.1093/texcom/tgac012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 02/21/2022] [Accepted: 03/01/2022] [Indexed: 11/13/2022] Open
Abstract
Susceptibility to the rubber hand illusion (RHI) varies. To date, however, there is no consensus explanation of this variability. Previous studies, focused on the role of multisensory integration, have searched for neural correlates of the illusion. But those studies have failed to identify a sufficient set of functionally specific neural correlates. Because some evidence suggests that frontal α power is one means of tracking neural instantiations of self, we hypothesized that the higher the frontal α power during the eyes-closed resting state, the more stable the self. As a corollary, we infer that the more stable the self, the less susceptible are participants to a blurring of boundaries—to feeling that the rubber hand belongs to them. Indeed, we found that frontal α amplitude oscillations negatively correlate with susceptibility. Moreover, since lower frequencies often modulate higher frequencies, we explored the possibility that this might be the case for the RHI. Indeed, some evidence suggests that high frontal α power observed in low-RHI participants is modulated by δ frequency oscillations. We conclude that while neural correlates of multisensory integration might be necessary for the RHI, sufficient explanation involves variable intrinsic neural activity that modulates how the brain responds to incompatible sensory stimuli.
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Affiliation(s)
- Tzu-Yu Hsu
- Graduate Institute of Mind, Brain, and Consciousness, Taipei Medical University, Taipei, Taiwan
- Brain and Consciousness Research Centre, TMU Shuang Ho Hospital, New Taipei City, Taiwan
| | - Ji-Fan Zhou
- Department of Psychology and Behavioral Sciences, Zhejiang University, Hang Zhou, China
| | - Su-Ling Yeh
- Department of Psychology, National Taiwan University, Taipei, Taiwan
- Graduate Institute of Brain and Mind Sciences, National Taiwan University, Taipei, Taiwan
- Neurobiology and Cognitive Neuroscience Center, National Taiwan University, Taipei, Taiwan
- Center for Artificial Intelligence and Advanced Robotics, National Taiwan University, Taipei, Taiwan
| | - Georg Northoff
- Institute of Mental Health Research, University of Ottawa, Ottawa, Canada
| | - Timothy Joseph Lane
- Graduate Institute of Mind, Brain, and Consciousness, Taipei Medical University, Taipei, Taiwan
- Brain and Consciousness Research Centre, TMU Shuang Ho Hospital, New Taipei City, Taiwan
- Institute of European and American Studies, Academia Sinica, Taipei, Taiwan
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17
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Gatus A, Jamieson G, Stevenson B. Past and Future Explanations for Depersonalization and Derealization Disorder: A Role for Predictive Coding. Front Hum Neurosci 2022; 16:744487. [PMID: 35321264 PMCID: PMC8934883 DOI: 10.3389/fnhum.2022.744487] [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: 07/20/2021] [Accepted: 01/27/2022] [Indexed: 11/17/2022] Open
Abstract
Depersonalization (DP) and derealization (DR) refer to states of dissociation in which one feels a sense of alienation in relation to one's self and environment, respectively. Whilst transient episodes often diminish without treatment, chronic experiences of DP and DR may last for years, with common treatments lacking a strong evidence base for their efficacy. We propose a theoretical explanation of DP and DR based on interoceptive predictive coding, and discuss how transient experiences of DP and DR may be induced in the non-clinical population using virtual reality. Further, we review the use of heartbeat evoked potentials in detecting the neural correlates of DP and DR allowing for an objective measure of these experiences in the non-clinical population. Finally, we discuss how the induction and detection of transient experiences of DP and DR in the non-clinical population could shed light on how the brain constructs one's sense of self and reality.
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Affiliation(s)
- Andrew Gatus
- Faculty of Medicine and Health, School of Psychology, University of New England, Armidale, NSW, Australia
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18
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Buetler KA, Penalver-Andres J, Özen Ö, Ferriroli L, Müri RM, Cazzoli D, Marchal-Crespo L. “Tricking the Brain” Using Immersive Virtual Reality: Modifying the Self-Perception Over Embodied Avatar Influences Motor Cortical Excitability and Action Initiation. Front Hum Neurosci 2022; 15:787487. [PMID: 35221950 PMCID: PMC8863605 DOI: 10.3389/fnhum.2021.787487] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 12/13/2021] [Indexed: 02/02/2023] Open
Abstract
To offer engaging neurorehabilitation training to neurologic patients, motor tasks are often visualized in virtual reality (VR). Recently introduced head-mounted displays (HMDs) allow to realistically mimic the body of the user from a first-person perspective (i.e., avatar) in a highly immersive VR environment. In this immersive environment, users may embody avatars with different body characteristics. Importantly, body characteristics impact how people perform actions. Therefore, alternating body perceptions using immersive VR may be a powerful tool to promote motor activity in neurologic patients. However, the ability of the brain to adapt motor commands based on a perceived modified reality has not yet been fully explored. To fill this gap, we “tricked the brain” using immersive VR and investigated if multisensory feedback modulating the physical properties of an embodied avatar influences motor brain networks and control. Ten healthy participants were immersed in a virtual environment using an HMD, where they saw an avatar from first-person perspective. We slowly transformed the surface of the avatar (i.e., the “skin material”) from human to stone. We enforced this visual change by repetitively touching the real arm of the participant and the arm of the avatar with a (virtual) hammer, while progressively replacing the sound of the hammer against skin with stone hitting sound via loudspeaker. We applied single-pulse transcranial magnetic simulation (TMS) to evaluate changes in motor cortical excitability associated with the illusion. Further, to investigate if the “stone illusion” affected motor control, participants performed a reaching task with the human and stone avatar. Questionnaires assessed the subjectively reported strength of embodiment and illusion. Our results show that participants experienced the “stone arm illusion.” Particularly, they rated their arm as heavier, colder, stiffer, and more insensitive when immersed with the stone than human avatar, without the illusion affecting their experienced feeling of body ownership. Further, the reported illusion strength was associated with enhanced motor cortical excitability and faster movement initiations, indicating that participants may have physically mirrored and compensated for the embodied body characteristics of the stone avatar. Together, immersive VR has the potential to influence motor brain networks by subtly modifying the perception of reality, opening new perspectives for the motor recovery of patients.
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Affiliation(s)
- Karin A. Buetler
- Motor Learning and Neurorehabilitation Laboratory, ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
- *Correspondence: Karin A. Buetler,
| | - Joaquin Penalver-Andres
- Motor Learning and Neurorehabilitation Laboratory, ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
- Psychosomatic Medicine, Department of Neurology, University Hospital of Bern (Inselspital), Bern, Switzerland
| | - Özhan Özen
- Motor Learning and Neurorehabilitation Laboratory, ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
| | - Luca Ferriroli
- Motor Learning and Neurorehabilitation Laboratory, ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
| | - René M. Müri
- Gerontechnology and Rehabilitation Group, ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
- Department of Neurology, University Neurorehabilitation, University Hospital of Bern (Inselspital), University of Bern, Bern, Switzerland
| | - Dario Cazzoli
- Gerontechnology and Rehabilitation Group, ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
- Department of Neurology, University Neurorehabilitation, University Hospital of Bern (Inselspital), University of Bern, Bern, Switzerland
- Neurocenter, Luzerner Kantonsspital, Lucerne, Switzerland
| | - Laura Marchal-Crespo
- Motor Learning and Neurorehabilitation Laboratory, ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
- Department of Cognitive Robotics, Delft University of Technology, Delft, Netherlands
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19
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Ataka K, Sudo T, Otaki R, Suzuki E, Izumi SI. Decreased Tactile Sensitivity Induced by Disownership: An Observational Study Utilizing the Rubber Hand Illusion. Front Syst Neurosci 2022; 15:802148. [PMID: 35126063 PMCID: PMC8811498 DOI: 10.3389/fnsys.2021.802148] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 12/22/2021] [Indexed: 11/13/2022] Open
Abstract
The sense of body ownership, the feeling that one’s own body belongs to oneself, is generated from the integration of visual, tactile, and proprioceptive information. However, long-term non-use of parts of the body due to physical dysfunction caused by trauma or illness may disturb multisensory integration, resulting in a decreased sense of body ownership. The rubber hand illusion (RHI) is an experimental method of manipulating the sense of ownership (SoO). In this illusion, subjects feel as if the rubber hand in front of them were their own hand. The RHI elicits the disownership phenomenon; not only does the rubber hand feels like one’s own hand, but one’s own hand does not feel like one’s own hand. The decrease of ownership of one’s own body induced by the bodily illusion is accompanied by neurophysiological changes, such as attenuation of somatosensory evoked potential and decreases in skin temperature. If the loss of the SoO is associated with decreased neurophysiological function, the dysfunction of patients complaining of the loss of ownership can be exacerbated; appropriate rehabilitation prescriptions are urgently required. The present study attempted to induce a sense of disownership of subjects’ own hands using the RHI and investigated whether the tactile sensitivity threshold was altered by disownership. Via questionnaire, subjects reported a decrease of ownership after the RHI manipulation; at the same time, tactile sensitivity thresholds were shown to increase in tactile evaluation using the Semmes-Weinstein monofilaments test. The tactile detection rate changes before and after the RHI were negatively correlated with the disownership-score changes. These results show that subjects’ sense of disownership, that their own hands did not belong to them, led to decreases in tactile sensitivity. The study findings also suggest that manipulating of illusory ownership can be a tool for estimating the degree of exacerbation of sensory impairment in patients. Consideration of new interventions that optimize the sense of body ownership may contribute to new rehabilitation strategies for post-stroke sensory impairment.
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Affiliation(s)
- Kota Ataka
- Department of Physical Medicine and Rehabilitation, Tohoku University Graduate School of Medicine, Sendai, Japan
- Department of Rehabilitation, Tohoku University Hospital, Sendai, Japan
| | - Tamami Sudo
- Department of Physical Medicine and Rehabilitation, Tohoku University Graduate School of Medicine, Sendai, Japan
- Department of Computer and Information Sciences, Graduate School of Engineering, Tokyo University of Agriculture and Technology, Tokyo, Japan
- *Correspondence: Tamami Sudo,
| | - Ryoji Otaki
- Department of Physical Medicine and Rehabilitation, Tohoku University Graduate School of Medicine, Sendai, Japan
- Department of Rehabilitation, Yamagata Saisei Hospital, Yamagata, Japan
| | - Eizaburo Suzuki
- Department of Physical Medicine and Rehabilitation, Tohoku University Graduate School of Medicine, Sendai, Japan
- Department of Physical Therapy, Yamagata Prefectural University of Health Sciences, Yamagata, Japan
| | - Shin-Ichi Izumi
- Department of Physical Medicine and Rehabilitation, Tohoku University Graduate School of Medicine, Sendai, Japan
- Department of Physical Medicine and Rehabilitation, Tohoku University Graduate School of Biomedical Engineering, Sendai, Japan
- Shin-Ichi Izumi,
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20
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Multivariate Analysis of Evoked Responses during the Rubber Hand Illusion Suggests a Temporal Parcellation into Manipulation and Illusion-Specific Correlates. eNeuro 2022; 9:ENEURO.0355-21.2021. [PMID: 34980661 PMCID: PMC8805188 DOI: 10.1523/eneuro.0355-21.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 11/16/2021] [Accepted: 12/13/2021] [Indexed: 11/23/2022] Open
Abstract
The neurophysiological processes reflecting body illusions such as the rubber hand remain debated. Previous studies investigating the neural responses evoked by the illusion-inducing stimulation have provided diverging reports as to when these responses reflect the illusory state of the artificial limb becoming embodied. One reason for these diverging reports may be that different studies contrasted different experimental conditions to isolate potential correlates of the illusion, but individual contrasts may reflect multiple facets of the adopted experimental paradigm and not just the illusory state. To resolve these controversies, we recorded EEG responses in human participants and combined multivariate (cross-)classification with multiple Illusion and non-Illusion conditions. These conditions were designed to probe for markers of the illusory state that generalize across the spatial arrangements of limbs or the specific nature of the control object (a rubber hand or participant’s real hand), hence which are independent of the precise experimental conditions used as contrast for the illusion. Our results reveal a parcellation of evoked responses into a temporal sequence of events. Around 125 and 275 ms following stimulus onset, the neurophysiological signals reliably differentiate the illusory state from non-Illusion epochs. These results consolidate previous work by demonstrating multiple neurophysiological correlates of the rubber hand illusion and illustrate how multivariate approaches can help pinpointing those that are independent of the precise experimental configuration used to induce the illusion.
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21
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The body-ownership is unconsciously distorted in the brain: An event-related potential study of rubber hand illusion. PSIHOLOGIJA 2022. [DOI: 10.2298/psi210126002l] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Many studies have reported that bottom-up multisensory integration of visual, tactile, and proprioceptive information can distort our sense of body-ownership, producing rubber hand illusion (RHI). There is less evidence about when and how the body-ownership is distorted in the brain during RHI. To examine whether this illusion effect occurs preattentively at an early stage of processing, we monitored the visual mismatch negativity (vMMN) component (the index of automatic deviant detection) and N2 (the index for conflict monitoring). Participants first performed an RHI elicitation task in a synchronous or asynchronous setting and then finished a passive visual oddball task in which the deviant stimuli were unrelated to the explicit task. A significant interaction between Deviancy (deviant hand vs. standard hand) and Group (synchronous vs. asynchronous) was found. The asynchronous group showed clear mismatch effects in both vMMN and N2, while the synchronous group had such effect only in N2. The results indicate that after the elicitation of RHI bottom-up integration could be retrieved at the early stage of sensory processing before top-down processing, providing evidence for the priority of the bottom-up processes after the generation of RHI and revealing the mechanism of how the body-ownership is unconsciously distorted in the brain.
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22
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Lanillos P, Franklin S, Maselli A, Franklin DW. Active strategies for multisensory conflict suppression in the virtual hand illusion. Sci Rep 2021; 11:22844. [PMID: 34819563 PMCID: PMC8613215 DOI: 10.1038/s41598-021-02200-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 11/08/2021] [Indexed: 11/09/2022] Open
Abstract
The perception of our body in space is flexible and manipulable. The predictive brain hypothesis explains this malleability as a consequence of the interplay between incoming sensory information and our body expectations. However, given the interaction between perception and action, we might also expect that actions would arise due to prediction errors, especially in conflicting situations. Here we describe a computational model, based on the free-energy principle, that forecasts involuntary movements in sensorimotor conflicts. We experimentally confirm those predictions in humans using a virtual reality rubber-hand illusion. Participants generated movements (forces) towards the virtual hand, regardless of its location with respect to the real arm, with little to no forces produced when the virtual hand overlaid their physical hand. The congruency of our model predictions and human observations indicates that the brain-body is generating actions to reduce the prediction error between the expected arm location and the new visual arm. This observed unconscious mechanism is an empirical validation of the perception-action duality in body adaptation to uncertain situations and evidence of the active component of predictive processing.
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Affiliation(s)
- Pablo Lanillos
- Donders Institute for Brain, Cognition and Behaviour, Artificial Intelligence Department, Radboud University, Thomas van Aquinostraat 4, 6525 GD, Nijmegen, The Netherlands.
| | - Sae Franklin
- Institute for Cognitive Systems, Technical University of Munich, Munich, Germany
| | - Antonella Maselli
- Institute of Cognitive Sciences and Technology, National Research Council (CNR), Rome, Italy
| | - David W Franklin
- Neuromuscular Diagnostics, Department of Sport and Health Sciences, Technical University of Munich, Munich, Germany.,Munich Institute of Robotics and Machine Intelligence (MIRMI), Technical University of Munich, Munich, Germany
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23
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Butler AA, Robertson LS, Wang AP, Gandevia SC, Héroux ME. Do interoception and attending to the upper limbs affect body ownership and body representation in the grasp illusion? PLoS One 2021; 16:e0259988. [PMID: 34788333 PMCID: PMC8598028 DOI: 10.1371/journal.pone.0259988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 10/29/2021] [Indexed: 11/18/2022] Open
Abstract
Passively grasping an unseen artificial finger induces ownership over this finger and an illusory coming together of one's index fingers: a grasp illusion. Here we determine how interoceptive ability and attending to the upper limbs influence this illusion. Participants passively grasped an unseen artificial finger with their left index finger and thumb for 3 min while their right index finger, located 12 cm below, was lightly clamped. Experiment 1 (n = 30) investigated whether the strength of the grasp illusion (perceived index finger spacing and perceived ownership) is related to a person's level of interoceptive accuracy (modified heartbeat counting task) and sensibility (Noticing subscale of the Multidimensional Assessment of Interoceptive Awareness). Experiment 2 (n = 30) investigated the effect of providing verbal or tactile cues to guide participants' attention to their upper limbs. On their own, neither interoceptive accuracy and sensibility or verbal and tactile cueing had an effect on the grasp illusion. However, verbal cueing increased the strength of the grasp illusion in individuals with lower interoceptive ability. Across the observed range of interoceptive accuracy and sensibility, verbal cueing decreased perceived index spacing by 5.6 cm [1.91 to 9.38] (mean [95%CI]), and perceived ownership by ∼3 points on a 7-point Likert scale (slope -0.93 [-1.72 to -0.15]). Thus, attending to the upper limbs via verbal cues increases the strength of the grasp illusion in a way that is inversely proportional to a person's level of interoceptive accuracy and sensibility.
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Affiliation(s)
- Annie A. Butler
- Neuroscience Research Australia, Randwick, NSW, Australia
- University of New South Wales, Randwick, NSW, Australia
| | - Lucy S. Robertson
- Neuroscience Research Australia, Randwick, NSW, Australia
- University of New South Wales, Randwick, NSW, Australia
| | | | - Simon C. Gandevia
- Neuroscience Research Australia, Randwick, NSW, Australia
- University of New South Wales, Randwick, NSW, Australia
| | - Martin E. Héroux
- Neuroscience Research Australia, Randwick, NSW, Australia
- University of New South Wales, Randwick, NSW, Australia
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24
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Rossi Sebastiano A, Bruno V, Ronga I, Fossataro C, Galigani M, Neppi-Modona M, Garbarini F. Diametrical modulation of tactile and visual perceptual thresholds during the rubber hand illusion: a predictive coding account. PSYCHOLOGICAL RESEARCH 2021; 86:1830-1846. [PMID: 34773491 DOI: 10.1007/s00426-021-01608-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 10/06/2021] [Indexed: 11/29/2022]
Abstract
During the rubber hand illusion (RHI), the synchronous stroking of the participants' concealed hand and a visible rubber hand induces a conflict among visuo-tactile inputs, leading healthy subjects to perceive the illusion of being touched on the rubber hand, as if it were part of their body. The predictive coding theory suggests that the RHI emerges to settle the conflict, attenuating somatosensory inputs in favour of visual ones, which "capture" tactile sensations. Here, we employed the psychophysical measure of perceptual threshold to measure a behavioural correlate of the somatosensory and visual modulations, to better understand the mechanisms underpinning the illusion. Before and after the RHI, participants underwent a tactile (Experiment 1) and a visual (Experiment 2) task, wherein they had to detect stimuli slightly above the perceptual threshold. According to the predictive coding framework, we found a significant decrease of tactile detection (i.e. increased tactile perceptual threshold) and a significant increase of visual detection (i.e. decreased visual perceptual threshold), suggesting a diametrical modulation of somatosensory and visual perceptual processes. These findings provide evidence of how our system plastically adapts to uncertainty, attributing different weights to sensory inputs to restore a coherent representation of the own body.
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Affiliation(s)
- Alice Rossi Sebastiano
- MANIBUS Lab, Department of Psychology, University of Turin, Via Verdi 10, 10124, Turin, Italy
| | - Valentina Bruno
- MANIBUS Lab, Department of Psychology, University of Turin, Via Verdi 10, 10124, Turin, Italy
| | - Irene Ronga
- MANIBUS Lab, Department of Psychology, University of Turin, Via Verdi 10, 10124, Turin, Italy
| | - Carlotta Fossataro
- MANIBUS Lab, Department of Psychology, University of Turin, Via Verdi 10, 10124, Turin, Italy
| | - Mattia Galigani
- MANIBUS Lab, Department of Psychology, University of Turin, Via Verdi 10, 10124, Turin, Italy
| | - Marco Neppi-Modona
- MANIBUS Lab, Department of Psychology, University of Turin, Via Verdi 10, 10124, Turin, Italy
| | - Francesca Garbarini
- MANIBUS Lab, Department of Psychology, University of Turin, Via Verdi 10, 10124, Turin, Italy. .,NIT, Neuroscience Institute of Turin, Turin, Italy.
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25
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Fabig SC, Kersebaum D, Lassen J, Sendel M, Jendral S, Muntean A, Baron R, Hüllemann P. A modality-specific somatosensory evoked potential test protocol for clinical evaluation: A feasibility study. Clin Neurophysiol 2021; 132:3104-3115. [PMID: 34740042 DOI: 10.1016/j.clinph.2021.08.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 07/26/2021] [Accepted: 08/29/2021] [Indexed: 10/20/2022]
Abstract
OBJECTIVE We aimed to establish an objective neurophysiological test protocol that can be used to assess the somatosensory nervous system. METHODS In order to assess most fiber subtypes of the somatosensory nervous system, repetitive stimuli of seven different modalities (touch, vibration, pinprick, cold, contact heat, laser, and warmth) were synchronized with the electroencephalogram (EEG) and applied on the cheek and dorsum of the hand and dorsum of the foot in 21 healthy subjects and three polyneuropathy (PNP) patients. Latencies and amplitudes of the modalities were assessed and compared. Patients received quantitative sensory testing (QST) as reference. RESULTS We found reproducible evoked potentials recordings for touch, vibration, pinprick, contact-heat, and laser stimuli. The recording of warm-evoked potentials was challenging in young healthy subjects and not applicable in patients. Latencies were shortest within Aβ-fiber-mediated signals and longest within C-fibers. The test protocol detected function loss within the Aβ-fiber and Aδ-fiber-range in PNP patients. This function loss corresponded with QST findings. CONCLUSION In this pilot study, we developed a neurophysiological test protocol that can specifically assess most of the somatosensory modalities. Despite technical challenges, initial patient data appear promising regarding a possible future clinical application. SIGNIFICANCE Established and custom-made stimulators were combined to assess different fiber subtypes of the somatosensory nervous system using modality-specific evoked potentials.
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Affiliation(s)
- Sophie-Charlotte Fabig
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Arnold-Heller-Straße 3, Haus D, 24105 Kiel, Germany.
| | - Dilara Kersebaum
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Arnold-Heller-Straße 3, Haus D, 24105 Kiel, Germany
| | - Josephine Lassen
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Arnold-Heller-Straße 3, Haus D, 24105 Kiel, Germany
| | - Manon Sendel
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Arnold-Heller-Straße 3, Haus D, 24105 Kiel, Germany
| | - Swantje Jendral
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Arnold-Heller-Straße 3, Haus D, 24105 Kiel, Germany
| | - Alexandra Muntean
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Arnold-Heller-Straße 3, Haus D, 24105 Kiel, Germany
| | - Ralf Baron
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Arnold-Heller-Straße 3, Haus D, 24105 Kiel, Germany
| | - Philipp Hüllemann
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Arnold-Heller-Straße 3, Haus D, 24105 Kiel, Germany
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Di Pino G, Mioli A, Altamura C, D'Alonzo M. Embodying an artificial hand increases blood flow to the investigated limb. OPEN RESEARCH EUROPE 2021; 1:55. [PMID: 35747768 PMCID: PMC7612882 DOI: 10.12688/openreseurope.13641.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 10/28/2021] [Indexed: 08/31/2023]
Abstract
Background: The autonomic nervous system is the main determinant of the blood flow directed towards a body part, and it is tightly connected to the representation of the body in the brain; would the experimental modulation of the sense of ownership of the limb affect its blood perfusion? Methods: In healthy participants, we employed the rubber hand illusion paradigm to modulate limb ownership while we monitored the brachial artery blood flow and resistance of the investigated limb. Results: In all conditions with brush-stroking, we found an initial drop in the blood flow due to tactile stimulation. Subsequently, in the illusion condition where both the rubber and real hand experience synchronous brush-stroking, the blood flow rose significantly faster and reached significantly higher values. Moreover, the increase in blood flow correlated to the embodiment level measured by questionnaires and, negatively, to the change of peripherical vascular resistance. Conclusions: These findings demonstrate that modulating the representation of a body part impacts its blood perfusion.
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Affiliation(s)
- Giovanni Di Pino
- NeXT: Neurophysiology and Neuroengineering of Human-Technology Interaction Research Unit, Campus Bio-Medico University of Rome, via Alvaro del Portillo, 5, Rome, 00128, Italy
| | - Alessandro Mioli
- NeXT: Neurophysiology and Neuroengineering of Human-Technology Interaction Research Unit, Campus Bio-Medico University of Rome, via Alvaro del Portillo, 5, Rome, 00128, Italy
| | - Claudia Altamura
- Headache and Neurosonology Unit, Neurology, Campus Bio-Medico University of Rome, via Alvaro del Portillo, 200, Rome, 00128, Italy
| | - Marco D'Alonzo
- NeXT: Neurophysiology and Neuroengineering of Human-Technology Interaction Research Unit, Campus Bio-Medico University of Rome, via Alvaro del Portillo, 5, Rome, 00128, Italy
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Precision control for a flexible body representation. Neurosci Biobehav Rev 2021; 134:104401. [PMID: 34736884 DOI: 10.1016/j.neubiorev.2021.10.023] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 10/20/2021] [Accepted: 10/21/2021] [Indexed: 11/24/2022]
Abstract
Adaptive body representation requires the continuous integration of multisensory inputs within a flexible 'body model' in the brain. The present review evaluates the idea that this flexibility is augmented by the contextual modulation of sensory processing 'top-down'; which can be described as precision control within predictive coding formulations of Bayesian inference. Specifically, I focus on the proposal that an attenuation of proprioception may facilitate the integration of conflicting visual and proprioceptive bodily cues. Firstly, I review empirical work suggesting that the processing of visual vs proprioceptive body position information can be contextualised 'top-down'; for instance, by adopting specific attentional task sets. Building up on this, I review research showing a similar contextualisation of visual vs proprioceptive information processing in the rubber hand illusion and in visuomotor adaptation. Together, the reviewed literature suggests that proprioception, despite its indisputable importance for body perception and action control, can be attenuated top-down (through precision control) to facilitate the contextual adaptation of the brain's body model to novel visual feedback.
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Altered effective connectivity in sensorimotor cortices is a signature of severity and clinical course in depression. Proc Natl Acad Sci U S A 2021; 118:2105730118. [PMID: 34593640 PMCID: PMC8501855 DOI: 10.1073/pnas.2105730118] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/13/2021] [Indexed: 12/24/2022] Open
Abstract
Research into neurobiology of depression primarily focuses on its complex psychological aspects. Here we propose an alternative approach and target sensorimotor alterations—a prominent but often neglected feature of depression. We demonstrated using resting-state functional MRI data and computational modeling that top-down and bottom-up information flow in sensory and motor cortices is altered with increasing depression severity in a way that is consistent with depression symptoms. Depression-associated changes were found to be consistent across sessions, amenable to treatment and of effect size sufficiently large to predict whether somebody has mild or severe depression. These results pave the way for an avenue of research into the neural underpinnings of mental health conditions. Functional neuroimaging research on depression has traditionally targeted neural networks associated with the psychological aspects of depression. In this study, instead, we focus on alterations of sensorimotor function in depression. We used resting-state functional MRI data and dynamic causal modeling (DCM) to assess the hypothesis that depression is associated with aberrant effective connectivity within and between key regions in the sensorimotor hierarchy. Using hierarchical modeling of between-subject effects in DCM with parametric empirical Bayes we first established the architecture of effective connectivity in sensorimotor cortices. We found that in (interoceptive and exteroceptive) sensory cortices across participants, the backward connections are predominantly inhibitory, whereas the forward connections are mainly excitatory in nature. In motor cortices these parities were reversed. With increasing depression severity, these patterns are depreciated in exteroceptive and motor cortices and augmented in the interoceptive cortex, an observation that speaks to depressive symptomatology. We established the robustness of these results in a leave-one-out cross-validation analysis and by reproducing the main results in a follow-up dataset. Interestingly, with (nonpharmacological) treatment, depression-associated changes in backward and forward effective connectivity partially reverted to group mean levels. Overall, altered effective connectivity in sensorimotor cortices emerges as a promising and quantifiable candidate marker of depression severity and treatment response.
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Alaydin HC, Cengiz B. Body ownership, sensorimotor integration and motor cortical excitability: A TMS study about rubber hand illusion. Neuropsychologia 2021; 161:107992. [PMID: 34391807 DOI: 10.1016/j.neuropsychologia.2021.107992] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 08/02/2021] [Accepted: 08/10/2021] [Indexed: 11/26/2022]
Abstract
OBJECTIVE The Rubber Hand Illusion (RHI) manipulates body ownership experimentally and helps investigate the related neurophysiological processes. This study aimed to evaluate motor cortex excitability that hypothesized changed due to illusion. METHOD Twenty-one healthy (twelve male, nine female), right-handed volunteers aged between 25 and 50 years were recruited to the study. Short-Latency Afferent Inhibition (SAI) was evaluated by transcranial magnetic stimulation (TMS) given with a figure-of-eight-shaped coil from the left motor cortex, 21 ms after peripheral electrical stimulation. Short-Interval Intracortical Inhibition (SICI) and Intracortical Facilitation (ICF) were investigated using a paired-pulse TMS at interstimulus intervals (ISI) of 1, 2.5, 3 ms and 15, 20, 25 ms, respectively. We used custom-made illusion setups for TMS paradigms. SAI, SICI and ICF was evaluated before, during and 15 min after the RHI. RESULTS Results of the study revealed significantly high SAI during illusion compared to pre-illusion, but no difference was found between post-illusion 15th minutes and control measurements. Significantly reduced SICI at 2.5 and 3 ms ISI obtained during illusion, while RHI did not affect SICI at 1 ms ISI and ICF. SIGNIFICANCE Body ownership illusion modulates the motor cortex excitability, possibly through altered sensory processing and sensorimotor integration.
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Affiliation(s)
- Halil Can Alaydin
- - Department of Neurology, Gazi University Faculty of Medicine, Ankara, Turkey; - Department of Neurology, Clinical Neurophysiology Division, Gazi University Faculty of Medicine, Ankara, Turkey.
| | - Bülent Cengiz
- - Department of Neurology, Gazi University Faculty of Medicine, Ankara, Turkey; - Department of Neurology, Clinical Neurophysiology Division, Gazi University Faculty of Medicine, Ankara, Turkey
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Golaszewski S, Frey V, Thomschewski A, Sebastianelli L, Versace V, Saltuari L, Trinka E, Nardone R. Neural mechanisms underlying the Rubber Hand Illusion: A systematic review of related neurophysiological studies. Brain Behav 2021; 11:e02124. [PMID: 34288558 PMCID: PMC8413782 DOI: 10.1002/brb3.2124] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 02/28/2021] [Accepted: 03/14/2021] [Indexed: 12/15/2022] Open
Abstract
INTRODUCTION Many researchers took advantage of the well-established rubber hand illusion (RHI) paradigm to explore the link between the sense of body ownership and the different brain structures and networks. Here, we aimed to review the studies that have investigated this phenomenon by means of neurophysiological techniques. METHODS The MEDLINE, accessed by Pubmed and EMBASE electronic databases, was searched using the medical subject headings: "Rubber hand illusion" AND "Transcranial magnetic stimulation (TMS)" OR "Evoked potentials (EP)" OR "Event related potentials (ERP)" OR "Electroencephalography (EEG)". RESULTS Transcranial magnetic stimulation studies revealed a significant excitability drop in primary motor cortex hand circuits accompanying the disembodiment of the real hand during the RHI experience and that the perceived ownership over the rubber hand is associated with normal parietal-motor communication. Moreover, TMS provided causal evidence that the extrastriate body area is involved in the RHI and subsequently in body representation, while neuromodulation of ventral premotor area and the inferior parietal lobe did not result in an enhancement of embodiment. EP and ERP studies suggest that pre-existing body representations may affect larger stages of tactile processing and support predictive coding models of the functional architecture of multisensory integration in bodily perceptual experience. High-frequency oscillations on EEG play a role in the integrative processing of stimuli across modalities, and EEG activity in γ band activity in the parietal area reflects the visuotactile integration process. EEG studies also revealed that RHI is associated with the neural circuits underlying motor control and that premotor areas play a crucial role in mediating illusory body ownership. CONCLUSION Neurophysiological studies shed new light on our understanding of the different aspects that contribute to the formation of a coherent self-awareness in humans.
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Affiliation(s)
- Stefan Golaszewski
- Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University, Salzburg, Austria.,Karl Landsteiner Institut für Neurorehabilitation und Raumfahrtneurologie, Salzburg, Austria
| | - Vanessa Frey
- Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University, Salzburg, Austria.,Spinal Cord Injury and Tissue Regeneration Center, Salzburg, Austria
| | - Aljoscha Thomschewski
- Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University, Salzburg, Austria.,Spinal Cord Injury and Tissue Regeneration Center, Salzburg, Austria
| | - Luca Sebastianelli
- Department of Neurorehabilitation, Hospital of Vipiteno (SABES-ASDAA), Vipiteno-Sterzing, Italy.,Research Unit for Neurorehabilitation South Tyrol, Bolzano, Italy
| | - Viviana Versace
- Department of Neurorehabilitation, Hospital of Vipiteno (SABES-ASDAA), Vipiteno-Sterzing, Italy.,Research Unit for Neurorehabilitation South Tyrol, Bolzano, Italy
| | - Leopold Saltuari
- Department of Neurorehabilitation, Hospital of Vipiteno (SABES-ASDAA), Vipiteno-Sterzing, Italy.,Research Unit for Neurorehabilitation South Tyrol, Bolzano, Italy
| | - Eugen Trinka
- Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University, Salzburg, Austria.,Karl Landsteiner Institut für Neurorehabilitation und Raumfahrtneurologie, Salzburg, Austria.,Centre for Cognitive Neuroscience Salzburg, Salzburg, Austria.,University for Medical Informatics and Health Technology, UMIT, Hall in Tirol, Austria
| | - Raffaele Nardone
- Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University, Salzburg, Austria.,Karl Landsteiner Institut für Neurorehabilitation und Raumfahrtneurologie, Salzburg, Austria.,Spinal Cord Injury and Tissue Regeneration Center, Salzburg, Austria.,Department of Neurology, Hospital of Merano (SABES-ASDAA), Merano-Meran, Italy
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Attenuation of sensory processing in the primary somatosensory cortex during rubber hand illusion. Sci Rep 2021; 11:7329. [PMID: 33795770 PMCID: PMC8016907 DOI: 10.1038/s41598-021-86828-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 03/22/2021] [Indexed: 12/03/2022] Open
Abstract
The neural representation of the body is easily altered by the integration of multiple sensory signals in the brain. The “rubber hand illusion” (RHI) is one of the most popular experimental paradigms to investigate this phenomenon. During this illusion, a feeling of ownership of the rubber hand is created. Some studies have shown that somatosensory processing in the brain is attenuated when RHI occurs. However, it is unknown where attenuation of somatosensory processing occurs. Here, we show that somatosensory processing is attenuated in the primary somatosensory cortex. We found that the earliest response of somatosensory evoked potentials, which is thought to originate from the primary somatosensory cortex, was attenuated during RHI. Furthermore, this attenuation was observed before the occurrence of the illusion. Our results suggest that attenuation of sensory processing in the primary somatosensory cortex is one of the factors influencing the occurrence of the RHI.
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Connectivity Analysis during Rubber Hand Illusion-A Pilot TMS-EEG Study in a Patient with SCI. Neural Plast 2021; 2021:6695530. [PMID: 33628223 PMCID: PMC7884106 DOI: 10.1155/2021/6695530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 01/12/2021] [Accepted: 01/28/2021] [Indexed: 11/17/2022] Open
Abstract
Background Bodily self-perception is an important concept for several neurological disorders, including spinal cord injury (SCI). Changing one's bodily self-perception, e.g., via rubber hand illusion (RHI), induces alterations of bottom-up and top-down pathways and with this the connectivity between involved brain areas. We aim to examine whether (1) this process can be manipulated by changing cortical excitability, (2) connectivity between relevant brain areas differ when the RHI cannot be evoked, and (3) how this projection differs in a patient with SCI. Method We applied RHI and facilitatory theta burst stimulation (TBS) on the right primary somatosensory cortex (S1) of 18 healthy participants and one patient with incomplete, cervical SCI. During RHI, we recorded high-density electroencephalography (HD-EEG) and extracted directed and nondirected connectivity measures. Results There is no difference in connectivity between sham and real TBS or in the effectivity of RHI. We observed a higher laterality in the patient, i.e., higher connectivity of the right and lower of the left hemisphere. Besides this, connectivity patterns do not differ between healthy participants and the patient. Conclusion This connectivity pattern might represent a neuroplastic response in the attempt to overcome the functional impairment of the patient resulting in a similar overall connectivity pattern to the healthy participants, yet with a higher sensitivity towards RHI and a higher laterality. The cortico-cortical communication was not altered depending on whether the illusion was provoked or not; hence, the perceptory illusion could not be observed in the EEG analysis.
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Pyasik M, Ronga I, Burin D, Salatino A, Sarasso P, Garbarini F, Ricci R, Pia L. I'm a believer: Illusory self-generated touch elicits sensory attenuation and somatosensory evoked potentials similar to the real self-touch. Neuroimage 2021; 229:117727. [PMID: 33434613 DOI: 10.1016/j.neuroimage.2021.117727] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 12/27/2020] [Accepted: 12/31/2020] [Indexed: 02/06/2023] Open
Abstract
Sensory attenuation (i.e., the phenomenon whereby self-produced sensations are perceived as less intense compared to externally occurring ones) is among the neurocognitive processes that help distinguishing ourselves from others. It is thought to be rooted in the motor system (e.g., related to motor intention and prediction), while the role of body awareness, which necessarily accompanies any voluntary movement, in this phenomenon is largely unknown. To fill this gap, here we compared the perceived intensity, somatosensory evoked potentials, and alpha-band desynchronization for self-generated, other-generated, and embodied-fake-hand-generated somatosensory stimuli. We showed that sensory attenuation triggered by the own hand and by the embodied fake hand had the same behavioral and neurophysiological signatures (reduced subjective intensity, reduced of N140 and P200 SEP components and post-stimulus alpha-band desynchronization). Therefore, signals subserving body ownership influenced attenuation of somatosensory stimuli, possibly in a postdictive manner. This indicates that body ownership is crucial for distinguishing the source of the perceived sensations.
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Affiliation(s)
- Maria Pyasik
- SAMBA (SpAtial, Motor and Bodily Awareness) Research Group, Department of Psychology, University of Turin, 10123 Turin, Italy; NPSY-Lab.VR, Department of Human Sciences, University of Verona, 37129 Verona, Italy
| | - Irene Ronga
- MANIBUS - Movement ANd body In Behavioral and physiological neUroScience research group, Department of Psychology, University of Turin, 10123 Turin, Italy
| | - Dalila Burin
- IDAC - Institute of Development, Aging and Cancer, SARC - Smart-Aging Research Center, Kawashima Laboratory, Tohoku University, Sendai, Japan
| | - Adriana Salatino
- SAMBA (SpAtial, Motor and Bodily Awareness) Research Group, Department of Psychology, University of Turin, 10123 Turin, Italy
| | - Pietro Sarasso
- SAMBA (SpAtial, Motor and Bodily Awareness) Research Group, Department of Psychology, University of Turin, 10123 Turin, Italy
| | - Francesca Garbarini
- MANIBUS - Movement ANd body In Behavioral and physiological neUroScience research group, Department of Psychology, University of Turin, 10123 Turin, Italy
| | - Raffaella Ricci
- SAMBA (SpAtial, Motor and Bodily Awareness) Research Group, Department of Psychology, University of Turin, 10123 Turin, Italy; NIT (Neuroscience Institute of Turin), 10123 Turin, Italy
| | - Lorenzo Pia
- SAMBA (SpAtial, Motor and Bodily Awareness) Research Group, Department of Psychology, University of Turin, 10123 Turin, Italy; NIT (Neuroscience Institute of Turin), 10123 Turin, Italy.
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Fritsch A, Lenggenhager B, Bekrater-Bodmann R. Prosthesis embodiment and attenuation of prosthetic touch in upper limb amputees - A proof-of-concept study. Conscious Cogn 2020; 88:103073. [PMID: 33360821 DOI: 10.1016/j.concog.2020.103073] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 10/29/2020] [Accepted: 12/14/2020] [Indexed: 12/27/2022]
Abstract
Sensory attenuation of self-touch, that is, the perceptual reduction of self-generated tactile stimuli, is considered a neurocognitive basis for self-other distinction. However, whether this effect can also be found in upper limb amputees using a prosthesis is unknown. Thirteen participants were asked to touch their foot sole with a) their intact hand (self-touch), b) their prosthesis (prosthesis-touch), or c) let it be touched by another person (other-touch). Intensity of touch was assessed with a questionnaire. In addition, prosthesis embodiment was assessed in nine participants. Self-touch as well as prosthesis-touch was characterized by significant perceptual attenuation compared to other-touch, while self- and prosthesis-touch did not differ. The more embodied the prosthesis was, the more similar was its elicited touch perception to actual self-touch. These findings - although preliminary - suggest that perceptually embodied prostheses can be represented as an actual limb by the users' sensorimotor system.
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Affiliation(s)
- Antonia Fritsch
- Department of Cognitive and Clinical Neuroscience, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | | | - Robin Bekrater-Bodmann
- Department of Cognitive and Clinical Neuroscience, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
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Lindner S, Latoschik ME, Rittner H. [Use of Virtual Reality as a Component of Acute and Chronic Pain Treatment]. Anasthesiol Intensivmed Notfallmed Schmerzther 2020; 55:549-561. [PMID: 32916738 DOI: 10.1055/a-1022-3038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Future or reality? Treating acute and chronic pain is a part of the daily routine of clinical anesthesiologists. Commonly used analgesics have unwanted side effects or may even be insufficient as in chronic pain treatment. Virtual Reality (VR) could be a promising new approach which offers noninvasive therapy options for the treatment of pain. In case of the opioid misuse the adjunctive treatment is mandatory. Various phenomena occur in VR, such as immersion, presence, embodiment and Proteus effect, which can cause a change in body awareness and behavior. Experimental and clinical studies already yielded some promising results for analgesic effects for acute and chronic pain conditions using VR simulation. Potential analgesic mechanisms include distraction, cognitive behavioral change, and distance from reality, leading to neurophysiological changes at the cortical level. The quality of the virtual environment, personalized avatars, as well as the possibility of interaction and multisensory input can increase immersion, which leads to a state of presence, and thus effective VR. VR can be used as an immersive extension or alternative to mirror therapy, especially for pain disorders such as complex regional pain syndrome (CRPS) or phantom limb pain. VR can be supplemented by gamification, which increases intrinsic motivation, well-being and adherence to therapy. In summary, VR could be an effective and realistic therapy option for acute and chronic pain in clinical and home settings in the future.
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Crivelli D, Balconi M. Extending the Body Ownership to Affective Experience of an Embodied Artificial Hand: a Power Spectra Investigation. Multisens Res 2020; 34:441-453. [PMID: 33706268 DOI: 10.1163/22134808-bja10037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 08/13/2020] [Indexed: 11/19/2022]
Abstract
According to implicit accounts, human self-awareness grounds on the so-called sense of ownership (SoO). Empirical investigations of SoO have mostly focused on the manipulation of self-ascription of sensations and experiences involving the body via the induction of bodily illusions, such as the Rubber-Hand Illusion (RHI). While it has been proposed that the affective dimension necessarily contributes to the development of a full ownership ascription, the relationship between affective experience and body ownership still presents many open questions. This study thus aimed at investigating the boundaries of ownership ascriptions and the extent to which an external object can be incorporated within one's own body representation, with a specific focus on the possibility for it to become a potential object of own affective experience marked by specific electrophysiological responses. Therefore, we induced RHI in 16 participants and then applied an aversive vs. pleasant stimulation to the embodied external object, while monitoring their electrophysiological activity for central physiological markers of affective processing. Data analysis revealed the effect of the stimulation condition on alpha band power over frontal areas, with higher alpha power during the pleasant stimulation condition with respect to the aversive stimulation one over medial and right frontal electrode sites. The present findings add to the limited pieces of evidence concerning the link between experiences of illusory body ownership, embodiment mechanisms, and affective factors, suggesting that the boundaries of body ownership might be extended to making incorporated objects the source of complex emotional responses beyond basic defensive reactions.
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Affiliation(s)
- Davide Crivelli
- Research Unit in Affective and Social Neuroscience, Catholic University of the Sacred Heart, Largo Gemelli 1, 20123 Milan, Italy.,Department of Psychology, Catholic University of the Sacred Heart, Largo Gemelli 1, 20123 Milan, Italy
| | - Michela Balconi
- Research Unit in Affective and Social Neuroscience, Catholic University of the Sacred Heart, Largo Gemelli 1, 20123 Milan, Italy.,Department of Psychology, Catholic University of the Sacred Heart, Largo Gemelli 1, 20123 Milan, Italy
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37
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The anatomo-clinical picture of the pathological embodiment over someone else's body part after stroke. Cortex 2020; 130:203-219. [DOI: 10.1016/j.cortex.2020.05.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 11/26/2019] [Accepted: 05/04/2020] [Indexed: 12/12/2022]
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Lim H, Kim WS, Ku J. Transcranial Direct Current Stimulation Effect on Virtual Hand Illusion. CYBERPSYCHOLOGY BEHAVIOR AND SOCIAL NETWORKING 2020; 23:541-549. [PMID: 32478563 DOI: 10.1089/cyber.2019.0741] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Virtual reality (VR) is effectively used to evoke the mirror illusion, and transcranial direct current stimulation (tDCS) synergistically facilitates this illusion. This study investigated whether a mirror virtual hand illusion (MVHI) induced by an immersive, first-person-perspective, virtual mirror system could be modulated by tDCS of the primary motor cortex. Fourteen healthy adults (average age 21.86 years ±0.47, seven men and seven women) participated in this study, and they experienced VR with and without tDCS-the tDCS and sham conditions, each of which takes ∼30 minutes-on separate days to allow the washout of the tDCS effect. While experiencing VR, the movements of the virtual left hand reflected the flexion and extension of the real right hand. Subsequently, electroencephalogram was recorded, the magnitude of the proprioceptive shift was measured, and the participants provided responses to a questionnaire regarding hand ownership. A significant difference in the proprioceptive shift was observed between the tDCS and sham conditions. In addition, there was significant suppression of the mu power in Pz, and augmentation of the beta power in the Pz, P4, O1, and O2 channels. The difference in proprioceptive deviation between the two conditions showed significant negative correlation with mu suppression over the left frontal lobe in the tDCS condition. Finally, the question "I felt that the virtual hand was my own hand" received a significantly higher score under the tDCS condition. In short, applying tDCS over the motor cortex facilitates the MVHI by activating the attentional network over the parietal and frontal lobes such that the MVHI induces more proprioceptive drift, which suggests that the combination of VR and tDCS can enhance the immersive effect in VR. This result provides better support for the use of the MVHI paradigm in combination with tDCS for recovery from illnesses such as stroke.
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Affiliation(s)
- Hyunmi Lim
- Department of Biomedical Engineering, School of Medicine, Keimyung University, Daegu, Republic of Korea
| | - Won-Seok Kim
- Department of Rehabilitation Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Jeonghun Ku
- Department of Biomedical Engineering, School of Medicine, Keimyung University, Daegu, Republic of Korea
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39
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Guterstam A, Collins KL, Cronin JA, Zeberg H, Darvas F, Weaver KE, Ojemann JG, Ehrsson HH. Direct Electrophysiological Correlates of Body Ownership in Human Cerebral Cortex. Cereb Cortex 2020; 29:1328-1341. [PMID: 30496342 PMCID: PMC6373693 DOI: 10.1093/cercor/bhy285] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 10/23/2018] [Indexed: 01/22/2023] Open
Abstract
Over the past decade, numerous neuroimaging studies based on hemodynamic markers of brain activity have examined the feeling of body ownership using perceptual body-illusions in humans. However, the direct electrophysiological correlates of body ownership at the cortical level remain unexplored. To address this, we studied the rubber hand illusion in 5 patients (3 males and 2 females) implanted with intracranial electrodes measuring cortical surface potentials. Increased high-γ (70–200 Hz) activity, an index of neuronal firing rate, in premotor and intraparietal cortices reflected the feeling of ownership. In both areas, high-γ increases were intimately coupled with the subjective illusion onset and sustained both during and in-between touches. However, intraparietal activity was modulated by tactile stimulation to a higher degree than the premotor cortex through effective connectivity with the hand-somatosensory cortex, which suggests different functional roles. These findings constitute the first intracranial electrophysiological characterization of the rubber hand illusion and extend our understanding of the dynamic mechanisms of body ownership.
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Affiliation(s)
- Arvid Guterstam
- Princeton Neuroscience Institute, Princeton University, New Jersey, USA.,Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Kelly L Collins
- Department of Neurological Surgery, University of Washington, Seattle, WA, USA
| | - Jeneva A Cronin
- Department of Neurological Surgery, University of Washington, Seattle, WA, USA
| | - Hugo Zeberg
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Felix Darvas
- Departments Biomedical Engineering and Radiology, University of Washington, Seattle, WA, USA
| | - Kurt E Weaver
- Department of Radiology, University of Washington, Seattle, WA, USA.,Integrated Brain Imaging Center, UW Radiology, Seattle, WA, USA
| | - Jeffrey G Ojemann
- Department of Neurological Surgery, University of Washington, Seattle, WA, USA
| | - H Henrik Ehrsson
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
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40
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Effects of Rubber Hand Illusion and Excitatory Theta Burst Stimulation on Tactile Sensation: A Pilot Study. Neural Plast 2020; 2020:3069639. [PMID: 32318103 PMCID: PMC7152971 DOI: 10.1155/2020/3069639] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 03/11/2020] [Indexed: 12/14/2022] Open
Abstract
Synchronous visuotactile stimulation on the own hidden hand and a visible fake limb can alter bodily self-perception and influence spontaneous neuroplasticity. The rubber hand illusion (RHI) paradigm experimentally produces an illusion of rubber hand ownership and arm shift by simultaneously stroking a rubber hand in view and a participant's visually occluded hand. The aim of this cross-over, placebo-controlled, single-blind study was to assess whether RHI, in combination with high-frequency repetitive transcranial magnetic stimulation (rTMS) given as intermittent (excitatory) theta burst stimulation (iTBS) applied over the hand area of the primary sensory region (S1) can enhance tactile sensation in a group of 21 healthy subjects and one patient with cervical spinal cord injury. Four sessions covered all combinations of real and sham stimulations of the RHI and the TBS: real TBS and real RHI, real TBS and sham RHI, sham TBS and real RHI, and both conditions sham. The condition sham TBS and real RHI shows the greatest effect on the proprioceptive drift (median 2.3 cm, IQR 2) and on the score of RHI questionnaires (median 3, IQR 2) in the control group as well as in the real-real condition (median 2, IQR 2). The sham TBS and real RHI condition also shows the best results in the electrical perception test of the patient (median 1.9 mA). Conversely, the upregulation of the cortical excitability of S1 via TBS seems to impair the effect of the RHI. This might be due to a strengthening of the top-down connection between the central nervous system and the periphery, diminishing the RHI. This finding helps in understanding the mechanisms of top-down and bottom-up mechanisms in healthy subjects and patients with spinal cord injury. The RHI paradigm could represent an interesting therapeutic approach in improving tactile sensation and rTMS techniques could modulate these effects. Yet, further studies are needed, to examine the direction of the interaction effect of TMS and RH.
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41
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Acquisition of Ownership Illusion with Self-Disownership in Neurological Patients. Brain Sci 2020; 10:brainsci10030170. [PMID: 32183477 PMCID: PMC7139520 DOI: 10.3390/brainsci10030170] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 03/10/2020] [Accepted: 03/13/2020] [Indexed: 12/26/2022] Open
Abstract
The multisensory regions in frontoparietal cortices play a crucial role in the sense of body and self. Disrupting this sense may lead to a feeling of disembodiment, or more generally, a sense of disownership. Experimentally, this altered consciousness disappears during illusory own-body perceptions, increasing the intensity of perceived ownership for an external virtual limb. In many clinical conditions, particularly in individuals with a discontinuous or absent sense of bodily awareness, the brain may effortlessly create a convincing feeling of body ownership over a surrogate body or body part. The immediate visual input dominates the current bodily state and induces rapid plastic adaptation that reconfigures the dynamics of bodily representation, allowing the brain to acquire an alternative sense of body and self. Investigating strategies to deconstruct the lack of a normal sense of bodily ownership, especially after a neurological injury, may aid the selection of appropriate clinical treatment.
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42
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Zhao J, Manza P, Wiers C, Song H, Zhuang P, Gu J, Shi Y, Wang GJ, He D. Age-Related Decreases in Interhemispheric Resting-State Functional Connectivity and Their Relationship With Executive Function. Front Aging Neurosci 2020; 12:20. [PMID: 32161532 PMCID: PMC7054233 DOI: 10.3389/fnagi.2020.00020] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Accepted: 01/21/2020] [Indexed: 11/13/2022] Open
Abstract
Age-related alterations of functional brain networks contribute to cognitive decline. Current theories indicate that age-related intrinsic brain functional reorganization may be a critical marker of cognitive aging. Yet, little is known about how intrinsic interhemispheric functional connectivity changes with age in adults, and how this relates to critical executive functions. To address this, we examined voxel-mirrored homotopic connectivity (VMHC), a metric that quantifies interhemispheric communication, in 93 healthy volunteers (age range: 19-85) with executive function assessment using the Delis-Kaplan Executive Function System (D-KEFS) scales. Resting functional MRI data were analyzed to assess VMHC, and then a multiple linear regression model was employed to evaluate the relationship between age and the whole-brain VMHC. We observed age-related reductions in VMHC of ventromedial prefrontal cortex (vmPFC) and hippocampus in the medial temporal lobe subsystem, dorsal anterior cingulate cortex and insula in salience network, and inferior parietal lobule in frontoparietal control network. Performance on the color-word inhibition task was associated with VMHC of vmPFC and insula, and VMHC of vmPFC mediated the relationship between age and CWIT inhibition reaction times. The percent ratio of correct design scores in design fluency test correlated positively with VMHC of the inferior parietal lobule. The current study suggests that brain interhemispheric functional alterations may be a promising new avenue for understanding age-related cognitive decline.
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Affiliation(s)
- Jizheng Zhao
- College of Mechanical and Electronic Engineering, Northwest A&F University, Yangling, China
- Key Laboratory of Agricultural Internet of Things, Ministry of Agriculture, Yangling, China
- Shaanxi Key Laboratory of Agricultural Information Perception and Intelligent Service, Yangling, China
| | - Peter Manza
- Laboratory of Neuroimaging, National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD, United States
| | - Corinde Wiers
- Laboratory of Neuroimaging, National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD, United States
| | - Huaibo Song
- College of Mechanical and Electronic Engineering, Northwest A&F University, Yangling, China
- Key Laboratory of Agricultural Internet of Things, Ministry of Agriculture, Yangling, China
- Shaanxi Key Laboratory of Agricultural Information Perception and Intelligent Service, Yangling, China
| | - Puning Zhuang
- College of Mechanical and Electronic Engineering, Northwest A&F University, Yangling, China
- Key Laboratory of Agricultural Internet of Things, Ministry of Agriculture, Yangling, China
- Shaanxi Key Laboratory of Agricultural Information Perception and Intelligent Service, Yangling, China
| | - Jun Gu
- Department of Endocrinology, First Affiliated Hospital of Hebei North University, Zhangjiakou, China
| | - Yinggang Shi
- College of Mechanical and Electronic Engineering, Northwest A&F University, Yangling, China
| | - Gene-Jack Wang
- Laboratory of Neuroimaging, National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD, United States
| | - Dongjian He
- College of Mechanical and Electronic Engineering, Northwest A&F University, Yangling, China
- Key Laboratory of Agricultural Internet of Things, Ministry of Agriculture, Yangling, China
- Shaanxi Key Laboratory of Agricultural Information Perception and Intelligent Service, Yangling, China
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43
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Schettler A, Raja V, Anderson ML. The Embodiment of Objects: Review, Analysis, and Future Directions. Front Neurosci 2019; 13:1332. [PMID: 31920499 PMCID: PMC6923672 DOI: 10.3389/fnins.2019.01332] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 11/26/2019] [Indexed: 12/11/2022] Open
Abstract
Here we offer a thorough review of the empirical literature on the conditions under which an object, such as a tool or a prosthetic (whether real or virtual), can be experienced as being in some sense a part or extension of one's body. We discuss this literature both from the standpoint of the apparent malleability of our body representations, and also from within the framework of radical embodied cognition, which understands the phenomenon to result not from an alteration to a representation, but rather from the achievement of a certain kind of sensory/motor coupling. We highlight both the tensions between these frameworks, and also areas where they can productively complement one another for future research.
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Affiliation(s)
- Aubrie Schettler
- Department of Philosophy, Western University Canada, London, ON, Canada.,Rotman Institute of Philosophy, Western University Canada, London, ON, Canada
| | - Vicente Raja
- Rotman Institute of Philosophy, Western University Canada, London, ON, Canada
| | - Michael L Anderson
- Department of Philosophy, Western University Canada, London, ON, Canada.,Rotman Institute of Philosophy, Western University Canada, London, ON, Canada.,Brain and Mind Institute, Western University Canada, London, ON, Canada
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44
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Connolly P. The Gravity of Objects: How Affectively Organized Generative Models Influence Perception and Social Behavior. Front Psychol 2019; 10:2599. [PMID: 31824382 PMCID: PMC6881275 DOI: 10.3389/fpsyg.2019.02599] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 11/01/2019] [Indexed: 11/13/2022] Open
Abstract
Friston's (2010) free energy principle (FEP) offers an opportunity to rethink what is meant by the psychoanalytic concept of an object or discrete mental representation (Ogden, 1992). The significance of such objects in psychoanalysis is that they may be superimposed on current experience so that perceptions are partly composed of projected fantasy and partly of more realistic perception. From a free energy perspective, the psychoanalytic (person) object may be understood as a bounded set of prior beliefs about a "platonic" sort of person that provides a free energy minimizing, evidence maximizing, hypothesis to explain inference about - or dyadic interactions with - another. The degree to which realistic perception supervenes - relative to a platonic person object - will depend upon the precision assigned to the sensory evidence (concerning the person) relative to the prior beliefs about a platonic form. This provides a basis for not only explaining projection and transference phenomena but also conceptualizing a central assumption within the object relations psychoanalysis. As an example, the paper examines the Kleinian theory of split good or bad part objects as affectively organized generative models (or platonic part-object models) formed in early infancy. This also provides a basis for building on work by Kernberg (1984, 1996) by conceptualizing the role of the part object(s) in a continuum of reality testing, from mild errors in perception that are relatively easily corrected, through borderline affective instability and frequent shifts between part-object experience, to psychotic failures of reality testing, where Friston et al. (2016) proposed that aberrant precisions bias perception to high precision false beliefs (here cast as platonic part objects), such as stable perceptions of others (and possibly oneself) as persecutory agents of some sort. The paper demonstrates the value that the history of clinical insights into psychoanalysis (including object relations) and a system-based approach to the brain (including the free energy principle) can have for one another. This is offered as a demonstration of the potential value of an "Integrative Clinical Systems Psychology" proposed by Tretter and Lo¨ffler-Stastka (2018), which has the potential to integrate the major theoretical frameworks in the field today.
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Affiliation(s)
- Patrick Connolly
- Counselling and Psychology Department, Hong Kong Shue Yan University, North Point, Hong Kong
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45
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Ponzo S, Kirsch LP, Fotopoulou A, Jenkinson PM. Vestibular modulation of multisensory integration during actual and vicarious tactile stimulation. Psychophysiology 2019; 56:e13430. [DOI: 10.1111/psyp.13430] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 05/28/2019] [Accepted: 06/08/2019] [Indexed: 11/30/2022]
Affiliation(s)
- Sonia Ponzo
- School of Life and Medical Sciences University of Hertfordshire Hertfordshire UK
| | - Louise P. Kirsch
- Clinical, Educational & Health Psychology Research Department, Division of Psychology & Language Sciences University College London London UK
- Institut des Systèmes Intelligents et de Robotique Sorbonne Université Paris France
| | - Aikaterini Fotopoulou
- Clinical, Educational & Health Psychology Research Department, Division of Psychology & Language Sciences University College London London UK
| | - Paul M. Jenkinson
- School of Life and Medical Sciences University of Hertfordshire Hertfordshire UK
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46
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Carhart-Harris RL, Friston KJ. REBUS and the Anarchic Brain: Toward a Unified Model of the Brain Action of Psychedelics. Pharmacol Rev 2019; 71:316-344. [PMID: 31221820 PMCID: PMC6588209 DOI: 10.1124/pr.118.017160] [Citation(s) in RCA: 363] [Impact Index Per Article: 72.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
This paper formulates the action of psychedelics by integrating the free-energy principle and entropic brain hypothesis. We call this formulation relaxed beliefs under psychedelics (REBUS) and the anarchic brain, founded on the principle that-via their entropic effect on spontaneous cortical activity-psychedelics work to relax the precision of high-level priors or beliefs, thereby liberating bottom-up information flow, particularly via intrinsic sources such as the limbic system. We assemble evidence for this model and show how it can explain a broad range of phenomena associated with the psychedelic experience. With regard to their potential therapeutic use, we propose that psychedelics work to relax the precision weighting of pathologically overweighted priors underpinning various expressions of mental illness. We propose that this process entails an increased sensitization of high-level priors to bottom-up signaling (stemming from intrinsic sources), and that this heightened sensitivity enables the potential revision and deweighting of overweighted priors. We end by discussing further implications of the model, such as that psychedelics can bring about the revision of other heavily weighted high-level priors, not directly related to mental health, such as those underlying partisan and/or overly-confident political, religious, and/or philosophical perspectives. SIGNIFICANCE STATEMENT: Psychedelics are capturing interest, with efforts underway to bring psilocybin therapy to marketing authorisation and legal access within a decade, spearheaded by the findings of a series of phase 2 trials. In this climate, a compelling unified model of how psychedelics alter brain function to alter consciousness would have appeal. Towards this end, we have sought to integrate a leading model of global brain function, hierarchical predictive coding, with an often-cited model of the acute action of psychedelics, the entropic brain hypothesis. The resulting synthesis states that psychedelics work to relax high-level priors, sensitising them to liberated bottom-up information flow, which, with the right intention, care provision and context, can help guide and cultivate the revision of entrenched pathological priors.
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Affiliation(s)
- R L Carhart-Harris
- Centre for Psychedelic Research, Division of Brain Sciences, Imperial College London, London, United Kingdom (R.L.C.-H.); and Institute of Neurology, Wellcome Trust Centre for Neuroimaging, University College London, London, United Kingdom (K.J.F.)
| | - K J Friston
- Centre for Psychedelic Research, Division of Brain Sciences, Imperial College London, London, United Kingdom (R.L.C.-H.); and Institute of Neurology, Wellcome Trust Centre for Neuroimaging, University College London, London, United Kingdom (K.J.F.)
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Hornburger H, Nguemeni C, Odorfer T, Zeller D. Modulation of the rubber hand illusion by transcranial direct current stimulation over the contralateral somatosensory cortex. Neuropsychologia 2019; 131:353-359. [PMID: 31078549 DOI: 10.1016/j.neuropsychologia.2019.05.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 05/07/2019] [Accepted: 05/08/2019] [Indexed: 01/13/2023]
Abstract
In the rubber hand illusion (RHI), illusory bodily ownership is induced by synchronous touch of a participant's hidden hand and a visible surrogate. This paradigm allows investigating how the brain resolves conflicting multisensory evidence during perceptual inference. Previous studies suggest that the conflict between visual and proprioceptive information preceding the RHI is solved by attenuation of the somatosensory input. To investigate whether excitability-decreasing transcranial direct current stimulation (cathodal tDCS) over the primary somatosensory cortex may enhance the RHI, thirty healthy subjects underwent RHI without (baseline) and during tDCS. Each subject received cathodal, anodal, and sham stimulation at independent sessions on three separate days. The RHI paradigm was applied at six interval distances between the real and artificial hand. Occurrence of the RHI was evaluated by a questionnaire (illusion score) and the perceived hand misplacement (relative drift). Compared to sham, neither cathodal, nor anodal tDCS induced significant changes of the illusion score. However, cathodal tDCS was associated with significantly higher illusion scores compared to anodal stimulation. The relative drift was comparable between stimulation modes. Our findings point to a differential impact of cathodal vs. anodal tDCS over the somatosensory region on RHI perception. This may indicate that an attenuation - in contrast to an enhancement - of somatosensory precision might pave the way for the integration of an artificial limb into one's body schema.
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Affiliation(s)
- Hannah Hornburger
- Dept. of Neurology, University of Würzburg, 97080, Würzburg, Germany
| | - Carine Nguemeni
- Dept. of Neurology, University of Würzburg, 97080, Würzburg, Germany
| | - Thorsten Odorfer
- Dept. of Neurology, University of Würzburg, 97080, Würzburg, Germany
| | - Daniel Zeller
- Dept. of Neurology, University of Würzburg, 97080, Würzburg, Germany.
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48
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Crucianelli L, Serpell L, Paloyelis Y, Ricciardi L, Robinson P, Jenkinson P, Fotopoulou A. The effect of intranasal oxytocin on the perception of affective touch and multisensory integration in anorexia nervosa: protocol for a double-blind placebo-controlled crossover study. BMJ Open 2019; 9:e024913. [PMID: 30878983 PMCID: PMC6429868 DOI: 10.1136/bmjopen-2018-024913] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
INTRODUCTION Anorexia nervosa (AN) is an eating disorder characterised by restriction of energy intake, fears of gaining weight and related body image disturbances. The oxytocinergic system has been proposed as a pathophysiological candidate for AN. Oxytocin is a neuropeptide involved in bodily processes (eg, breast feeding) and in the onset of social behaviours (eg, bonding). Studies investigating the effect of intranasal oxytocin (IN-OT) in AN showed that it can improve attentional bias for high-calorie food and fat bodies stimuli, and related stress. However, less is known about the effect of IN-OT on bodily awareness and body image distortions, key features of the disorder linked to its development, prognosis and maintenance. Here, we aim to investigate the effect of IN-OT on the perception of affective, C-tactile-optimal touch, known to be impaired in AN and on multisensory integration processes underlying a body ownership illusion (ie, rubber hand illusion). For exploratory purposes, we will also investigate the effect of IN-OT on another interoceptive modality, namely cardiac awareness and its relationship with affective touch. DESIGN, METHODS AND ANALYSIS Forty women with AN and forty matched healthy controls will be recruited and tested in two separate sessions; self-administering IN-OT (40 IU) or placebo, intranasally, in a pseudo-randomised manner. The data from this double-blind, placebo-controlled, cross-over study will be analysed using linear mixed models that allow the use of both fixed (treatment levels) and random (subjects) effects in the same analysis. To address our main hypotheses, separate analyses will be run for the affective touch task, where the primary outcome dependent variable will be the pleasantness of the touch, and for the rubber hand illusion, where we will investigate multisensory integration quantified as subjective embodiment towards the rubber hand. In the latter, we will manipulate the synchronicity of touch and the size of the hand. ETHICS AND DISSEMINATION Ethics approval has been obtained by National Research Ethics Service NRES Committee London (Queen's Square Committee, ref number 14/LO/1593). The results will be disseminated through conference presentations and publication in peer-reviewed journals.
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Affiliation(s)
- Laura Crucianelli
- Department of Clinical, Educational and Health Psychology, University College London, London, UK
| | - Lucy Serpell
- Department of Clinical, Educational and Health Psychology, University College London, London, UK
| | - Yannis Paloyelis
- Department of Neuroimaging Science, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, UK
| | - Lucia Ricciardi
- Cardiovascular Sciences Research Centre, St George’s Hospital, London, UK
| | - Paul Robinson
- Barnet Enfield and Haringey Mental Health Trust, London, UK
- Faculty of Medical Sciences, University College London, London, UK
| | - Paul Jenkinson
- Department of Psychology and Sport Sciences, University of Hertfordshire, Hatfield, UK
| | - Aikaterini Fotopoulou
- Department of Clinical, Educational and Health Psychology, University College London, London, UK
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49
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The Effect of Visual Capture Towards Subjective Embodiment Within the Full Body Illusion. Sci Rep 2019; 9:2889. [PMID: 30814561 PMCID: PMC6393432 DOI: 10.1038/s41598-019-39168-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 12/31/2018] [Indexed: 12/28/2022] Open
Abstract
Typically, multisensory illusion paradigms emphasise the importance of synchronous visuotactile integration to induce subjective embodiment towards another body. However, the extent to which embodiment is due to the 'visual capture' of congruent visuoproprioceptive information alone remains unclear. Thus, across two experiments (total N = 80), we investigated how mere visual observation of a mannequin body, viewed from a first-person perspective, influenced subjective embodiment independently from concomitant visuotactile integration. Moreover, we investigated whether slow, affective touch on participants' own, unseen body (without concomitant touch on the seen mannequin) disrupted visual capture effects to a greater degree than fast, non-affective touch. In total, 40% of participants experienced subjective embodiment towards the mannequin body following mere visual observation, and this effect was significantly higher than conditions which included touch to participants own, unseen body. The velocity of the touch that participants received (affective/non-affective) did not differ in modulating visual capture effects. Furthermore, the effects of visual capture and perceived pleasantness of touch was not modulated by subthreshold eating disorder psychopathology. Overall, this study suggests that congruent visuoproprioceptive cues can be sufficient to induce subjective embodiment of a whole body, in the absence of visuotactile integration and beyond mere confabulatory responses.
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50
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Filippetti ML, Kirsch LP, Crucianelli L, Fotopoulou A. Affective certainty and congruency of touch modulate the experience of the rubber hand illusion. Sci Rep 2019; 9:2635. [PMID: 30796333 PMCID: PMC6385173 DOI: 10.1038/s41598-019-38880-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 01/03/2019] [Indexed: 11/09/2022] Open
Abstract
Our sense of body ownership relies on integrating different sensations according to their temporal and spatial congruency. Nevertheless, there is ongoing controversy about the role of affective congruency during multisensory integration, i.e. whether the stimuli to be perceived by the different sensory channels are congruent or incongruent in terms of their affective quality. In the present study, we applied a widely used multisensory integration paradigm, the Rubber Hand Illusion, to investigate the role of affective, top-down aspects of sensory congruency between visual and tactile modalities in the sense of body ownership. In Experiment 1 (N = 36), we touched participants with either soft or rough fabrics in their unseen hand, while they watched a rubber hand been touched synchronously with the same fabric or with a 'hidden' fabric of 'uncertain roughness'. In Experiment 2 (N = 50), we used the same paradigm as in Experiment 1, but replaced the 'uncertainty' condition with an 'incongruent' one, in which participants saw the rubber hand being touched with a fabric of incongruent roughness and hence opposite valence. We found that certainty (Experiment 1) and congruency (Experiment 2) between the felt and vicariously perceived tactile affectivity led to higher subjective embodiment compared to uncertainty and incongruency, respectively, irrespective of any valence effect. Our results suggest that congruency in the affective top-down aspects of sensory stimulation is important to the multisensory integration process leading to embodiment, over and above temporal and spatial properties.
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Affiliation(s)
- Maria Laura Filippetti
- Centre for Brain Science, Department of Psychology, University of Essex, CO4 3SQ, Colchester, UK. .,Research Department of Clinical, Educational & Health Psychology, University College London, WC1E 7HB, London, UK.
| | - Louise P Kirsch
- Research Department of Clinical, Educational & Health Psychology, University College London, WC1E 7HB, London, UK
| | - Laura Crucianelli
- Research Department of Clinical, Educational & Health Psychology, University College London, WC1E 7HB, London, UK
| | - Aikaterini Fotopoulou
- Research Department of Clinical, Educational & Health Psychology, University College London, WC1E 7HB, London, UK
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