Left caloric vestibular stimulation as a tool to reveal implicit and explicit parameters of body representation

Homeostatic parameters, such as temperature, are related to body representation. In thisstudy, we measured whether caloric vestibular stimulation (CVS) alters body temperatureand tactile processing, and if in the direction predicted by a holistic body matrix representation.Skin temperature and tactile two-point discrimination (TPD) acuity were measured forboth arms before, immediately after and with a delay from CVS. Participants were alsoadministered a personality questionnaire and an anxiety inventory to rule out confoundingfactors. Two control experiments were planned to exclude casual variations.Our results show that temperature drops significantly in both arms after CVS. CVS alsoinduces a bilateral improvement in tactile acuity (even though not immediately after butin the delayed condition). Finally, these effects are not due to learning, as demonstratedby the control experiment.In summary, our results suggest that vestibular stimulation updates body representation,supporting the evidence in favor of a body matrix.