Verticality Perception - Multisensory Contribution

The purpose of this study is to evaluate the relative contribution of head- and trunk-based sensory systems to internal estimates of direction of gravity in healthy human subjects. To implement this assessment experimentally, the investigators will use a motor-driven 3D-turntable and a thermoplastic mask to keep the head in a stable, either roll-tilted (±30°) or aligned with the trunk. The investigators will then obtain measurements of the subjective visual vertical in seven different whole-body roll positions (max. 90° roll-tilt). Analysis will be driven by a state-of-the art Bayesian integration model. The investigators hypothesize that different sensory input signals are combined in a statistically optimal fashion.