The right temporo parietal junction plays a causal role in maintaining the internal representation of verticality

Background: Perception of the subjective vertical is strongly based on our ability to constantly integrate signals from visual, vestibular, proprioceptive, tactile and even visceral modalities and matching them with an internal representation of the vertical. An important multisensory integration cortical region is the right temporo-parietal junction (rTPJ) which is also involved in higher-order forms of body- and space-related cognition. Aims: Test the hypothesis that TPJ is specifically involved in the integration of multisensory information necessary for establishing the subjective visual vertical. Method: We combined a psychophysical approach based on Rod-and-Frame task with transient inhibition of the right TPJ via continuous theta burst stimulation (cTBS). A gabor patch orientation detection task and cTBS of V1/V2 were used as control task and area respectively. Results: 3 Inhibition of rTPJ activity impairs the ability to evaluate the rod verticality when no contextual visual information is provided. Conversely, transient inhibition of V1/V2 disrupts the ability to visually discriminate gabors’ orientation. Conclusions: 4 This anatomo-functional dissociation supports the idea that rTPJ plays a causal role in maintaining an internal frame of reference against which contextual information is compared.