Shared neural mechanisms between imagined and perceived egocentric motion

Abstract Behavioral studies have suggested that mental projection of one’s own body to a different spatial location (egocentric mental rotation) relies on brain areas that are also involved in processing actual self-motion based on vestibular input. Using fMRI, we set out to investigate the brain areas that underlie both simulated changes of the self in mental space and vestibular processing within the same individuals. Participants performed an egocentric mental rotation task during simultaneous Galvanic Vestibular Stimulation (GVS) or sham stimulation. At the neural level, we expected an overlap between brain areas activated during vestibular processing and egocentric mental rotation within area OP2, a core brain region involved in vestibular processing. As predicted, the fMRI data showed an overlap of brain activity within area OP2 for both egocentric mental rotation and vestibular processing. GVS did not influence the ability to perform egocentric mental rotation. Our results provide evidence for shared neural mechanisms underlying perceived and simulated self-motion. We conclude that mental rotations of one’s body involve neural activity in area OP2, but also suggest that those mental simulations of one’s body might be robust to modulatory input from artificial vestibular stimulation.