The Electrophysiological Correlates of Multisensory Self-Motion Perception

Abstract

The perception of self-motion draws on inputs from the visual, vestibular and proprioceptive systems. Decades of behavioural research has shed light on constructs such as multisensory weighting, heading perception, and sensory thresholds, that are involved in self-motion perception. Despite the abundance of knowledge generated by behavioural studies, there is a clear lack of research exploring the neural processes associated with full-body, multisensory self-motion perception in humans. Much of what is known about the neural correlates of self-motion perception comes from either the animal literature, or from human neuroimaging studies only administering visual self-motion stimuli. The goal of this thesis was to bridge the gap between understanding the behavioural correlates of full-body self-motion perception, and the underlying neural processes of the human brain. We used a high-fidelity motion simulator to manipulate the interaction of the visual and vestibular systems to gain insights into cognitive processes related to self-motion perception. The present line of research demonstrated that theta, alpha and beta oscillations are the underlying electrophysiological oscillations associated with self-motion perception. Specifically, the three empirical chapters combine to contribute two main findings to our understanding of self-motion perception. First, the beta band is an index of visual-vestibular weighting. We demonstrated that beta event-related synchronization power is associated with visual weighting bias, and beta event-related desynchronization power is associated with vestibular weighting bias. Second, the theta band is associated with direction processing, regardless of whether direction information is provided through the visual or vestibular system. This research is the first of its kind and has opened the door for future research to further develop our understanding of biomarkers related to self-motion perception.