Spatial Sensory References for Vestibular Self-Motion Perception

While navigating through the surroundings, we constantly rely on inertial vestibular signals for self-motion along with visual and acoustic spatial references from the environment. However, the interaction between inertial cues and environmental spatial references is not yet fully understood. Here we investigated whether vestibular self-motion sensitivity is influenced by sensory spatial references. Healthy participants were administered a Vestibular Self-Motion Detection Task in which they were asked to detect vestibular self-motion sensations induced by low-intensity Galvanic Vestibular Stimulation. Participants performed this detection task with or without an external visual or acoustic spatial reference placed directly in front of them. We computed the d prime ( d ' ) as a measure of participants' vestibular sensitivity and the criterion as an index of their response bias. Results showed that the visual spatial reference increased sensitivity to detect vestibular self-motion. Conversely, the acoustic spatial reference did not influence self-motion sensitivity. Both visual and auditory spatial references did not cause changes in response bias. Environmental visual spatial references provide relevant information to enhance our ability to perceive inertial self-motion cues, suggesting a specific interaction between visual and vestibular systems in self-motion perception.