Shifting the body midline: The impact of visuomotor modulations in virtual reality on peripheral autonomic activity

A coherent sense of body ownership and position depends on the integration of top-down and bottom-up sensory signals. Disrupting this coherence through experimental illusions can alter body representation and peripheral physiological states, such as body temperature. To further investigate this link, we developed a novel virtual reality (VR) paradigm that manipulates spatial body representation by virtually repositioning the left hand into the right side of the body during a visuomotor task. Participants (n = 26) engaged in a 15-min immersive VR task using their right hand to manipulate a virtual cube with a stick. In the congruent condition, the virtual hand matched their actual right hand. In the incongruent condition, the right hand was visually replaced by a left hand, shifting the perceived body midline. We recorded left-hand temperature before and during the task, skin conductance responses (SCRs) to electrocutaneous stimulation, proprioceptive drift (PD), and subjective measures (embodiment, agency, altered body perception, and unpleasantness). Results showed a significant decrease in left-hand temperature in the incongruent condition, compared to an increase in the congruent condition. SCR amplitude correlated with temperature: cooling was associated with reduced SCRs, while warming predicted stronger responses. PD revealed a rightward shift in perceived finger position across conditions, likely due to the task's unilateral nature. Subjective ratings were similar across conditions. Overall, our findings demonstrate that visuomotor manipulations disrupting coherent body reference frames can induce measurable physiological changes, even in the absence of altered subjective experience, highlighting a link between body representation and peripheral bodily signals.