scholarly journals Constraints on object perception influence assimilation of objects into the body representation

2011 ◽  
Vol 11 (11) ◽  
pp. 871-871
Author(s):  
S. Larsen ◽  
T. Carlson
Keyword(s):  
Object Perception ◽  
Body Representation ◽  
The Body

The Role of Hand Size in the Fake-Hand Illusion Paradigm

Perception ◽  
10.1068/p5853 ◽  
2007 ◽  
Vol 36 (10) ◽  
pp. 1547-1554 ◽  
Author(s):  
Francesco Pavani ◽  
Massimiliano Zampini
Keyword(s):  
Body Image ◽  
Body Schema ◽  
Body Representation ◽  
The Body ◽  
Video Image ◽  
Body Parts ◽  
Statistical Correlations ◽  
Hand Size ◽  
Visible Hand

When a hand (either real or fake) is stimulated in synchrony with our own hand concealed from view, the felt position of our own hand can be biased toward the location of the seen hand. This intriguing phenomenon relies on the brain's ability to detect statistical correlations in the multisensory inputs (ie visual, tactile, and proprioceptive), but it is also modulated by the pre-existing representation of one's own body. Nonetheless, researchers appear to have accepted the assumption that the size of the seen hand does not matter for this illusion to occur. Here we used a real-time video image of the participant's own hand to elicit the illusion, but we varied the hand size in the video image so that the seen hand was either reduced, veridical, or enlarged in comparison to the participant's own hand. The results showed that visible-hand size modulated the illusion, which was present for veridical and enlarged images of the hand, but absent when the visible hand was reduced. These findings indicate that very specific aspects of our own body image (ie hand size) can constrain the multisensory modulation of the body schema highlighted by the fake-hand illusion paradigm. In addition, they suggest an asymmetric tendency to acknowledge enlarged (but not reduced) images of body parts within our body representation.

Triadic body representations in the human cerebral cortex and peripheral nerves

2021 ◽  
pp. 133-151 ◽  
Author(s):  
Noriaki Kanayama ◽  
Kentaro Hiromitsu
Keyword(s):  
Peripheral Nerves ◽  
Sensory Modality ◽  
Body Schema ◽  
Body Representation ◽  
Neural System ◽  
The Body ◽  
Neural Representation ◽  
Structural Description ◽  
Research Fields ◽  
The Brain

Is the body reducible to neural representation in the brain? There is some evidence that the brain contributes to the functioning of the body from neuroimaging, neurophysiological, and lesion studies. Well-known dyadic taxonomy of the body schema and the body image (hereafter BSBI) is based primarily on the evidence in brain-damaged patients. Although there is a growing consensus that the BSBI exists, there is little agreement on the dyadic taxonomy because it is not a concrete and common concept across various research fields. This chapter tries to investigate the body representation in the cortex and nervous system in terms of sensory modality and psychological function using two different approaches. The first approach is to review the neurological evidence and cortical area which is related to body representation, regardless of the BSBI, and then to reconsider how we postulate the BSBI in our brain. It can be considered that our body representation could be constructed by the whole of the neural system, including the cortex and peripheral nerves. The second approach is to revisit the BSBI conception from the viewpoint of recent neuropsychology and propose three types of body representation: body schema, body structural description, and body semantics. This triadic taxonomy is considered consistent with the cortical networks based on the evidence of bodily disorders due to brain lesions. These two approaches allow to reconsider the BSBI more carefully and deeply and to give us the possibility that the body representation could be underpinned with the network in the brain.

scholarly journals Hand/Face Border as a Limiting Boundary in the Body Representation in Monkey Somatosensory Cortex

1997 ◽  
Vol 17 (16) ◽  
pp. 6338-6351 ◽  
Author(s):  
Paul R. Manger ◽  
Timothy M. Woods ◽  
Alberto Muñoz ◽  
Edward G. Jones
Keyword(s):  
Somatosensory Cortex ◽  
Body Representation ◽  
The Body

scholarly journals Modulation of Body Representation Impacts on Efferent Autonomic Activity

2020 ◽  
Vol 32 (6) ◽  
pp. 1104-1116 ◽  
Author(s):  
Marco D'Alonzo ◽  
Alessandro Mioli ◽  
Domenico Formica ◽  
Giovanni Di Pino
Keyword(s):  
Nervous System ◽  
Autonomic Nervous System ◽  
Skin Conductance ◽  
Skin Conductance Response ◽  
Time Windows ◽  
Body Representation ◽  
The Body ◽  
Hand Position ◽  
Sensory Stimuli ◽  
Autonomic Nervous

The afferent branch of the autonomic nervous system contributes with interoception to the multimodal sensory correlation continuously needed to update our representation of the body. To test whether the modulation of body representation would have an impact on the efferent branch of the autonomic nervous system, nonspecific skin conductance has been measured in three rubber hand illusion (RHI) experiments, controlled with asynchronous brush-stroking and incongruent fake hand position. Nonspecific skin conductance standard deviation (SCSD) computed along the whole 90 sec of stroking was found to be increased by the illusion and to correlate with all the typical measures of embodiment. Computing SCSD in shorter time windows strongly enhanced the difference between illusion and controls. The highest difference was found in the 10–55 sec window, being the 14–34 sec window as the most informative one. The higher correlations with the validated measures of embodiment (all but the proprioceptive drift) were found for time windows ranging between 35 and 65 sec. The SCSD was no longer significantly higher when the RHI was repeated twice (two trials each iteration), but it was still significantly higher in synchronous stroking even when considering only the second trial. However, after the first iteration of the RHI paradigm, the effect of the embodiment on nonspecific skin conductance response results to be attenuated, suggesting that novelty in presentation of the RHI can contribute to the effect on nonspecific skin conductance response. Results candidate SCSD as a noninvasive, cheap, easy, and objective measure of embodiment, especially sensible to onset and strength of the illusion. Alike the already known enhanced autonomic reaction to a threatening, SCSD does not interfere with the collection of other behavioral measures. Correlations and their dynamics, presence of the effect in the second presentation of the setup but relative low robustness against multiple repetition, suggest that the increased fluctuations of skin conductance caught by SCSD are not just the effect of different presented sensory stimuli but more likely a stronger arousal response to the novelty of the updated perceptual status.

scholarly journals Effect of Body Representation Level of an Avatar on Quality of AR-Based Remote Instruction

2020 ◽  
Vol 4 (1) ◽  
pp. 3
Author(s):  
Tzu-Yang Wang ◽  
Yuji Sato ◽  
Mai Otsuki ◽  
Hideaki Kuzuoka ◽  
Yusuke Suzuki
Keyword(s):  
Augmented Reality ◽  
Body Representation ◽  
The Body ◽  
Instruction System ◽  
Three Body ◽  
To Receive ◽  
Representation Level

In manufacturing, augmented reality (AR)-based remote instruction systems, which enable workers to receive instructions from an avatar, are widely used. In this study, we developed such a system and investigated the effect of the body representation level of the avatar on the quality of AR-based remote instruction. Drawing on the avatar designs of previous works, three different avatar designs (“Hand only”, “Hand + Arm”, and “Body”), representing three body representation levels, were created. In the experiment with a within-participant design, the avatar pointed at blocks sequentially and participants touched each block as soon as they identified it. The results of the experiment indicate that an AR-based remote instruction system with a “Body” avatar exhibits higher usability and can enable the participants to have a lower workload and higher efficiency.

scholarly journals tDCS Modulation of Visually Induced Analgesia

2012 ◽  
Vol 24 (12) ◽  
pp. 2419-2427 ◽  
Author(s):  
Flavia Mancini ◽  
Nadia Bolognini ◽  
Patrick Haggard ◽  
Giuseppe Vallar
Keyword(s):  
Visual Cortex ◽  
Pain Perception ◽  
Occipital Cortex ◽  
Body Representation ◽  
The Body ◽  
Left Hand ◽  
Analgesic Effects ◽  
Extrastriate Visual Cortex ◽  
Multisensory Interactions ◽  
The Right

Multisensory interactions can produce analgesic effects. In particular, viewing one's own body reduces pain levels, perhaps because of changes in connectivity between visual areas specialized for body representation, and sensory areas underlying pain perception. We tested the causal role of the extrastriate visual cortex in triggering visually induced analgesia by modulating the excitability of this region with transcranial direct current stimulation (tDCS). Anodal, cathodal, or sham tDCS (2 mA, 10 min) was administered to 24 healthy participants over the right occipital or over the centro-parietal areas thought to be involved in the sensory processing of pain. Participants were required to rate the intensity of painful electrical stimuli while viewing either their left hand or an object occluding the left hand, both before and immediately after tDCS. We found that the analgesic effect of viewing the body was enhanced selectively by anodal stimulation of the occipital cortex. The effect was specific for the polarity and the site of stimulation. The present results indicate that visually induced analgesia may depend on neural signals from the extrastriate visual cortex.

scholarly journals Remote hand: Hand-centered peripersonal space transfers to a disconnected hand avatar

2021 ◽  
Author(s):  
Daisuke Mine ◽  
Kazuhiko Yokosawa
Keyword(s):  
Virtual Environment ◽  
Body Representation ◽  
Peripersonal Space ◽  
The Body ◽  
The Real ◽  
Novel Technique ◽  
Near Space ◽  
Behavioral Evidence ◽  
Real Hand

The space surrounding our body is called peripersonal space (PPS). It has been reported that visuo-tactile facilitation occurs more strongly within PPS than outside PPS. Furthermore, previous research has revealed several methods by which PPS can be extended. The present study provides the first behavioral evidence of the transfer of PPS in a virtual environment by a novel technique. PPS representation was investigated using a remote-controlled hand avatar presented far from their body in a virtual environment. Participants showed strongest visuo-tactile facilitation at the far space around the remote hand and no facilitation at the near space around the real hand, suggesting that PPS transfers from near the body to the space around the hand avatar. The present results extend previous findings of the plasticity of PPS and demonstrate flexibility of PPS representation beyond the physical and anatomical limits of body representation.

scholarly journals Implicit and Explicit Body Representations

2015 ◽  
Vol 20 (1) ◽  
pp. 6-15 ◽  
Author(s):  
Matthew R. Longo
Keyword(s):  
Sensory Information ◽  
Body Representation ◽  
Position Sense ◽  
The Body ◽  
Size Perception ◽  
Somatosensory Processing ◽  
Body Representations ◽  
Size And Shape ◽  
Tactile Localization ◽  
Somatosensory Information

Several forms of perception require that sensory information be referenced to representations of the size and shape of the body. This requirement is especially acute in somatosensation in which the main receptor surface (i.e., the skin) is itself coextensive with the body. This paper reviews recent research investigating the body representations underlying somatosensory information processing, including abilities such as tactile localization, tactile size perception, and position sense. These representations show remarkably large and stereotyped distortions of represented body size and shape. Intriguingly, these distortions appear to mirror distortions characteristic of somatosensory maps, though in attenuated form. In contrast, when asked to make overt judgments about perceived body form, participants are generally quite accurate. This pattern of results suggests that higher-level somatosensory processing relies on a class of implicit body representation, distinct from the conscious body image. I discuss the implications of these results for understanding the nature of body representation and the factors that influence it.

scholarly journals Bodily ownership of an independent supernumerary limb: An exploratory study

2021 ◽  
Author(s):  
Kohei Umezawa ◽  
Yuta Suzuki ◽  
Gowrishankar Ganesh ◽  
Yoichi Miyawaki
Keyword(s):  
Human Brain ◽  
Sensory Feedback ◽  
Body Representation ◽  
The Body ◽  
Artificial Limbs ◽  
Cognitive Measures ◽  
Rubber Hand ◽  
Artificial Limb ◽  
Sense Of Ownership ◽  
Induced Changes

AbstractCan our brain perceive a sense of ownership towards an independent supernumerary limb; one that can be moved independently of any other limb and provides its own independent movement feedback? Following the rubberhand illusion experiment, a plethora of studies has shown that the human representation of ‘self’ is very plastic. But previous studies have almost exclusively investigated ownership towards ‘substitute’ artificial limbs, which are controlled by the movements of a real limb and/or limbs from which non-visual sensory feedback is provided on an existing limb. Here, to investigate whether the human brain can own an independent artificial limb, we first developed a novel independent robotic ‘sixth finger.’ We allowed participants to train using the finger and examined whether it induced changes in the body representation using behavioral as well as cognitive measures. Our results suggest that unlike a substituted artificial limb (like in the rubber hand experiment), it is more difficult for humans to perceive a sense of ownership towards an independent limb. However, ownership does seem possible, as we observed clear tendencies of changes in the body representation that correlated with the cognitive reports of the sense of ownership. Our results provide the first evidence to show that an independent supernumerary limb can be embodied by the human brain.

scholarly journals How to lose a hand: Sensory updating drives disembodiment

2020 ◽  
Author(s):  
Roland Pfister ◽  
Annika L. Klaffehn ◽  
Andreas Kalckert ◽  
Wilfried Kunde ◽  
David Dignath
Keyword(s):  
Multisensory Integration ◽  
Body Representation ◽  
The Body ◽  
Rubber Hand ◽  
Body Representations ◽  
Dynamic View ◽  
Single Instance ◽  
Multisensory Input ◽  
To Receive ◽  
Real Hand

AbstractBody representations are readily expanded based on sensorimotor experience. A dynamic view of body representations, however, holds that these representations cannot only be expanded but that they can also be narrowed down by disembodying elements of the body representation that are no longer warranted. Here we induced illusory ownership in terms of a moving rubber hand illusion and studied the maintenance of this illusion across different conditions. We observed ownership experience to decrease gradually unless participants continued to receive confirmatory multisensory input. Moreover, a single instance of multisensory mismatch – a hammer striking the rubber hand but not the real hand – triggered substantial and immediate disembodiment. Together, these findings support and extend previous theoretical efforts to model body representations through basic mechanisms of multisensory integration. They further support an updating model suggesting that embodied entities fade from the body representation if they are not refreshed continuously.

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