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Towards a digital body: the virtual arm illusion.

Slater M, Perez-Marcos D, Ehrsson HH, Sanchez-Vives MV - Front Hum Neurosci (2008)

Bottom Line: Here we demonstrate that a virtual limb can be made to feel part of your body if appropriate multisensory correlations are provided.An experiment with 21 male participants showed displacement of ownership towards the virtual hand, as illustrated by questionnaire responses and proprioceptive drift.A completely virtual object can therefore be experienced as part of one's self, which opens up the possibility that an entire virtual body could be felt as one's own in future virtual reality applications or online games, and be an invaluable tool for the understanding of the brain mechanisms underlying body ownership.

View Article: PubMed Central - PubMed

Affiliation: Institució Catalana de Recerca i Estudis Avançats Barcelona, Spain. melslater@lsi.upc.edu

ABSTRACT
The integration of the human brain with computers is an interesting new area of applied neuroscience, where one application is replacement of a person's real body by a virtual representation. Here we demonstrate that a virtual limb can be made to feel part of your body if appropriate multisensory correlations are provided. We report an illusion that is invoked through tactile stimulation on a person's hidden real right hand with synchronous virtual visual stimulation on an aligned 3D stereo virtual arm projecting horizontally out of their shoulder. An experiment with 21 male participants showed displacement of ownership towards the virtual hand, as illustrated by questionnaire responses and proprioceptive drift. A control experiment with asynchronous tapping was carried out with a different set of 20 male participants who did not experience the illusion. After 5 min of stimulation the virtual arm rotated. Evidence suggests that the extent of the illusion was also correlated with the degree of muscle activity onset in the right arm as measured by EMG during this period that the arm was rotating, for the synchronous but not the asynchronous condition. A completely virtual object can therefore be experienced as part of one's self, which opens up the possibility that an entire virtual body could be felt as one's own in future virtual reality applications or online games, and be an invaluable tool for the understanding of the brain mechanisms underlying body ownership.

No MeSH data available.


Related in: MedlinePlus

Boxplots for the questionnaire responses in the two conditions. (A) Synchronous condition. (B) Asynchronous condition. Questions 1, 2 and 3 address the illusory experience. The medians are shown as red lines, and the boxes are the interquartile ranges (IQR). The whiskers represent either the extreme data points or extend to 1.5 × IQR. If there are values outside the whiskers these are conventionally called ‘outliers’, and are shown by (+).
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Figure 2: Boxplots for the questionnaire responses in the two conditions. (A) Synchronous condition. (B) Asynchronous condition. Questions 1, 2 and 3 address the illusory experience. The medians are shown as red lines, and the boxes are the interquartile ranges (IQR). The whiskers represent either the extreme data points or extend to 1.5 × IQR. If there are values outside the whiskers these are conventionally called ‘outliers’, and are shown by (+).

Mentions: The boxplots for the questionnaire results are shown in Figure 2. For the synchronous condition Q1–Q3 have higher scores than the remainder. For the asynchronous condition the results for Q1–Q3 are not significantly different from the remainder, and all the scores are low.


Towards a digital body: the virtual arm illusion.

Slater M, Perez-Marcos D, Ehrsson HH, Sanchez-Vives MV - Front Hum Neurosci (2008)

Boxplots for the questionnaire responses in the two conditions. (A) Synchronous condition. (B) Asynchronous condition. Questions 1, 2 and 3 address the illusory experience. The medians are shown as red lines, and the boxes are the interquartile ranges (IQR). The whiskers represent either the extreme data points or extend to 1.5 × IQR. If there are values outside the whiskers these are conventionally called ‘outliers’, and are shown by (+).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2572198&req=5

Figure 2: Boxplots for the questionnaire responses in the two conditions. (A) Synchronous condition. (B) Asynchronous condition. Questions 1, 2 and 3 address the illusory experience. The medians are shown as red lines, and the boxes are the interquartile ranges (IQR). The whiskers represent either the extreme data points or extend to 1.5 × IQR. If there are values outside the whiskers these are conventionally called ‘outliers’, and are shown by (+).
Mentions: The boxplots for the questionnaire results are shown in Figure 2. For the synchronous condition Q1–Q3 have higher scores than the remainder. For the asynchronous condition the results for Q1–Q3 are not significantly different from the remainder, and all the scores are low.

Bottom Line: Here we demonstrate that a virtual limb can be made to feel part of your body if appropriate multisensory correlations are provided.An experiment with 21 male participants showed displacement of ownership towards the virtual hand, as illustrated by questionnaire responses and proprioceptive drift.A completely virtual object can therefore be experienced as part of one's self, which opens up the possibility that an entire virtual body could be felt as one's own in future virtual reality applications or online games, and be an invaluable tool for the understanding of the brain mechanisms underlying body ownership.

View Article: PubMed Central - PubMed

Affiliation: Institució Catalana de Recerca i Estudis Avançats Barcelona, Spain. melslater@lsi.upc.edu

ABSTRACT
The integration of the human brain with computers is an interesting new area of applied neuroscience, where one application is replacement of a person's real body by a virtual representation. Here we demonstrate that a virtual limb can be made to feel part of your body if appropriate multisensory correlations are provided. We report an illusion that is invoked through tactile stimulation on a person's hidden real right hand with synchronous virtual visual stimulation on an aligned 3D stereo virtual arm projecting horizontally out of their shoulder. An experiment with 21 male participants showed displacement of ownership towards the virtual hand, as illustrated by questionnaire responses and proprioceptive drift. A control experiment with asynchronous tapping was carried out with a different set of 20 male participants who did not experience the illusion. After 5 min of stimulation the virtual arm rotated. Evidence suggests that the extent of the illusion was also correlated with the degree of muscle activity onset in the right arm as measured by EMG during this period that the arm was rotating, for the synchronous but not the asynchronous condition. A completely virtual object can therefore be experienced as part of one's self, which opens up the possibility that an entire virtual body could be felt as one's own in future virtual reality applications or online games, and be an invaluable tool for the understanding of the brain mechanisms underlying body ownership.

No MeSH data available.


Related in: MedlinePlus