UCLA

The perception of gravitational vertical is determined by estimates from visual, vestibular and proprioceptive sensory cues. This dissertation investigates the various ways in which these three sources of cues interact to produce a final estimate of the perception of vertical. Specifically, I utilize and validate verticality estimates made in virtual reality and exploit the adaptability of this methodology to probe visual contributions to vertical biases. I then explore the use of a novel methodology using galvanic vestibular stimulation to understand the effects of vestibular influences on verticality. In addition, I validate a vestibular-based orientation discrimination method that uses one’s body orientation to estimate the direction of vertical. I then explore the potential influences neck and body proprioceptive cues have on the visual and vestibular-based estimates made in the current investigations. Using the principles of Bayesian cue combination, I then test the optimal integration of verticality estimates based on single-cue estimates of vertical. Finally, I discuss the ways in which these interactions between sensory cues impact the susceptibility and propensity of particular disorders and ailments that result from maladaptive sensory integration.