Seeing and identifying with a virtual body decreases pain perception

Division of Psychosomatic Medicine, Department of General Internal Medicine, Inselspital, Bern University Hospital and University of Bern, Switzerland.
European journal of pain (London, England) (Impact Factor: 2.93). 05/2011; 15(8):874-9. DOI: 10.1016/j.ejpain.2011.03.013
Source: PubMed


Pain and the conscious mind (or the self) are experienced in our body. Both are intimately linked to the subjective quality of conscious experience. Here, we used virtual reality technology and visuo-tactile conflicts in healthy subjects to test whether experimentally induced changes of bodily self-consciousness (self-location; self-identification) lead to changes in pain perception. We found that visuo-tactile stroking of a virtual body but not of a control object led to increased pressure pain thresholds and self-location. This increase was not modulated by the synchrony of stroking as predicted based on earlier work. This differed for self-identification where we found as predicted that synchrony of stroking increased self-identification with the virtual body (but not a control object), and positively correlated with an increase in pain thresholds. We discuss the functional mechanisms of self-identification, self-location, and the visual perception of human bodies with respect to pain perception.

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Available from: Roland Von Känel, Jan 17, 2015
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    • "In a previous study, the effect of seeing a new dummy that embodied one's own body was unclear [11]–[13], [45]. In a previous study, it was unclear whether the effect of seeing embodied new dummy or virtual bodies [11]–[13], [45]. This difference in results is thought to be due to a difference in the experimental method. "
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    ABSTRACT: Changing the visual body appearance by use of as virtual reality system, funny mirror, or binocular glasses has been reported to be helpful in rehabilitation of pain. However, there are interindividual differences in the analgesic effect of changing the visual body image. We hypothesized that a negative body image associated with changing the visual body appearance causes interindividual differences in the analgesic effect although the relationship between the visual body appearance and analgesic effect has not been clarified. We investigated whether a negative body image associated with changes in the visual body appearance increased pain. Twenty-five healthy individuals participated in this study. To evoke a negative body image, we applied the method of rubber hand illusion. We created an "injured rubber hand" to evoke unpleasantness associated with pain, a "hairy rubber hand" to evoke unpleasantness associated with embarrassment, and a "twisted rubber hand" to evoke unpleasantness associated with deviation from the concept of normality. We also created a "normal rubber hand" as a control. The pain threshold was measured while the participant observed the rubber hand using a device that measured pain caused by thermal stimuli. Body ownership experiences were elicited by observation of the injured rubber hand and hairy rubber hand as well as the normal rubber hand. Participants felt more unpleasantness by observing the injured rubber hand and hairy rubber hand than the normal rubber hand and twisted rubber hand (p<0.001). The pain threshold was lower under the injured rubber hand condition than with the other conditions (p<0.001). We conclude that a negative body appearance associated with pain can increase pain sensitivity.
    Full-text · Article · Sep 2014 · PLoS ONE
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    • "In one of these studies (Hansel et al., 2011), the authors assessed pressure pain threshold on the index finger while using an out-of-body experience paradigm (third-person perspective approach). They reported that just the vision of the mannequin standing in front of the participants led to higher pain thresholds, independently of the identification with it (Hansel et al., 2011). In the other study, no effect of the rubber hand illusion was found on pain perception (Mohan et al., 2012). "
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    ABSTRACT: Appropriate sensorimotor correlations can result in the illusion of ownership of exogenous body parts. Nevertheless, whether and how the illusion of owning a new body part affects human perception, and in particular pain detection, is still poorly investigated. Recent findings have shown that seeing one's own body is analgesic, but it is not known whether this effect is transferable to newly embodied, but exogenous, body parts. In recent years, results from our laboratory have demonstrated that a virtual body can be felt as one's own, provided realistic multisensory correlations. The current work aimed at investigating the impact of virtual body ownership on pain threshold. An immersive virtual environment allowed a first-person perspective of a virtual body that replaced the own. Passive movement of the index finger congruent with the movement of the virtual index finger was used in the 'synchronous' condition to induce ownership of the virtual arm. The pain threshold was tested by thermal stimulation under four conditions: (1) synchronous movements of the real and virtual fingers; (2) asynchronous movements; (3) seeing a virtual object instead of an arm; and (4) not seeing any limb in real world. Our results show that, independently of attentional and stimulus adaptation processes, the ownership of a virtual arm per se can significantly increase the thermal pain threshold. This finding may be relevant for the development and improvement of digital solutions for rehabilitation and pain treatment.
    Full-text · Article · Aug 2014 · European journal of pain (London, England)
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    • "Experimental research shows that both spatial and non-spatial aspects of bodily self-consciousness emerge from pre-reflective and non-conceptual representations of bodily signals in the brain (Metzinger, 2003; Gallagher, 2005; Blanke and Metzinger, 2009; Ehrsson, 2012). Those are sensory signals from exteroception , such as visual and auditory signals (e.g., Ehrsson, 2007; Lenggenhager et al., 2007; Tajadura-Jiménez et al., 2009), from somatosensation, such as tactile and proprioceptive signals (e.g., Seizova-Cajic et al., 2007; Palluel et al., 2011; for reviews see Haggard et al., 2003; Serino and Haggard, 2010) and from interoception , such as cardiac, nociceptive, and thermal signals (Hänsel et al., 2011; Aspell et al., 2013; for an interoception-based account on consciousness see Craig, 2002, 2009). Altogether, these experimental studies imply that by integrating multisensory signals the brain generates a coherent spatial representation of body parts, the body as a whole, and the body as related to the external world. "
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    ABSTRACT: Self-consciousness is the remarkable human experience of being a subject: the "I". Self-consciousness is typically bound to a body, and particularly to the spatial dimensions of the body, as well as to its location and displacement in the gravitational field. Because the vestibular system encodes head position and movement in three-dimensional space, vestibular cortical processing likely contributes to spatial aspects of bodily self-consciousness. We review here recent data showing vestibular effects on first-person perspective (the feeling from where "I" experience the world) and self-location (the feeling where "I" am located in space). We compare these findings to data showing vestibular effects on mental spatial transformation, self-motion perception, and body representation showing vestibular contributions to various spatial representations of the body with respect to the external world. Finally, we discuss the role for four posterior brain regions that process vestibular and other multisensory signals to encode spatial aspects of bodily self-consciousness: temporoparietal junction, parietoinsular vestibular cortex, ventral intraparietal region, and medial superior temporal region. We propose that vestibular processing in these cortical regions is critical in linking multisensory signals from the body (personal and peripersonal space) with external (extrapersonal) space. Therefore, the vestibular system plays a critical role for neural representations of spatial aspects of bodily self-consciousness.
    Full-text · Article · Apr 2014 · Frontiers in Integrative Neuroscience
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