Vestibular modulation of multisensory integration during actual and vicarious tactile stimulation

Abstract

BackgroundThe vestibular system has been shown to contribute to multisensory integration by balancing conflictual sensory information. It remains unclear whether such modulation of exteroceptive (e.g. vision), proprioceptive and interoceptive (e.g. affective touch) sensory sources is influenced by epistemically different aspects of tactile stimulation (i.e. felt from within vs seen, vicarious touch).\n\nObjectiveWe aimed to i) replicate previous findings regarding the effects of galvanic stimulation of the right vestibular network (i.e. LGVS) in multisensory integration and ii) examine vestibular contributions to multisensory integration when touch is felt but not seen (and vice-versa).\n\nMethodDuring artificial vestibular stimulation (LGVS, RGVS and Sham), healthy participants (N=36, Experiment 1; N=37, Experiment 2) looked at a rubber hand while either their own unseen hand or the rubber hand were touched by affective or neutral touch.\n\nResultsWe found that i) LGVS led to enhancement of vision over proprioception during visual only conditions (replicating our previous findings), and ii) LGVS (vs Sham) favoured proprioception over vision when touch was felt (Experiment 1), with the opposite results when touch was vicariously perceived via vision (Experiment 2), and with no difference between affective and neutral touch.\n\nConclusionsWe showed how vestibular signals modulate the weight of each sensory modality according to the context in which they are perceived and that such modulation extends to different aspects of tactile stimulation: felt and seen touch are differentially balanced in multisensory integration according to their epistemic relevance.\n\nHighlightsO_LILGVS increased proprioceptive drift during vision of a rubber hand\nC_LIO_LITouch on participants hand decreased proprioceptive drift during LGVS\nC_LIO_LIVicarious touch on the Rubber Hand increased proprioceptive drift during LGVS\nC_LIO_LIVestibular signals differently balance sensory sources in multisensory integration\nC_LI