Abstract
Vection is an illusion of visually-induced self-motion in a stationary observer. This functional magnetic resonance imaging (fMRI) study measured psychophysical and blood oxygenation level-dependent (BOLD) responses to four different visual stimuli: (1) coherent optic flow simulating smooth forward self-motion, (2) coherent optic flow simulating forward self-motion combined with vertical head oscillation, and (3,4) scrambled versions of 1 and 2 respectively (which preserved local, but disrupted global, motion information). These stimuli were specifically designed to examine the interaction between visual and vestibular cortical regions during vection. The two coherent optic flow stimuli produced robust percepts of vection while the scrambled stimuli produced little or no vection. Of the putative self-motion areas we examined, the cingulate sulcus visual area (CSv) showed the clearest selective activation for coherent optic flow compared to incoherent (scrambled) flow suggesting that CSv is heavily involved in self-motion processing. Other regions such as parieto-insular vestibular cortex (PIVC), and precuneus visual region (Pc) showed change in BOLD activity during vection-inducing stimuli but to a lesser extent than CSv. These findings help clarify the relationship between visual and vestibular cortical regions during vection and highlight CSv as a region of primary importance in self-motion processing.
Meeting abstract presented at VSS 2015