The body fades away: investigating the effects of transparency of an embodied virtual body on pain threshold and body ownership

The ffeelffing off “ownershffip” over an external dummy/vffirtual body (or body part) has been proven to
have both physffiologffical and behavffioural consequences. For ffinstance, the vffisffion off an “embodffied”
dummy or vffirtual body can modulate paffin perceptffion. However, the ffimpact off partffial or total
ffinvffisffibffilffity off the body on physffiology and behavffiour has been hardly explored sffince ffit presents
obvffious dffifficultffies ffin the real world. In thffis study we explored how body transparency affects both
body ownershffip and paffin threshold. By means off vffirtual realffity, we presented healthy partfficffipants
wffith a vffirtual co-located body wffith ffour dffifferent levels off transparency, whffile partfficffipants were
tested ffor paffin threshold by ffincreasffing ramps off heat stffimulatffion. We ffound that the strength off
the body ownershffip ffillusffion decreases when the body gets more transparent. Nevertheless, ffin the
condffitffions where the body was semffi-transparent, hffigher levels off ownershffip over a see-through body
resulted ffin an ffincreased paffin sensffitffivffity. Vffirtual body ownershffip can be used ffor the development off
paffin management ffinterventffions. However, we demonstrate that provffidffing ffinvffisffibffilffity off the body
does not ffincrease paffin threshold. Thereffore, body transparency ffis not a good strategy to decrease
paffin ffin clffinffical contexts, yet thffis remaffins to be tested.