Simulated self-motion in a visual gravity field: Sensitivity to vertical and horizontal heading in the human brain

► Visual effects of gravitational field help to discriminate heading direction. ► We visually simulated self-motion along vertical and horizontal directions. ► Distinct neural representations of the cardinal axes of self-motion were found. ► Vertical self-motion coherent with gravity engaged the posterior insula. ► Medial-temporal regions were more activated by horizontal motion.