title: The right temporoparietal junction plays a causal role in maintaining the internal representation of verticality.
abstract: Perception of the visual vertical is strongly based on our ability to match visual inflow with vestibular, proprioceptive, tactile, and even visceral information that contributes to maintaining an internal representation of the vertical. An important cortical region implicated in multisensory integration is the right temporoparietal junction (rTPJ), which also is involved in higher order forms of body- and space-related cognition. To test whether this region integrates body-related multisensory information necessary for establishing the subjective visual vertical, we combined a psychophysical task (the rod-and-frame test) with transient inhibition of the rTPJ via continuous theta burst stimulation (cTBS). A Gabor patch visual detection task was used as a control visual task. cTBS of early visual cortex (V1-V3) was used to test whether early visual cortices played any role in verticality estimation. We show that inhibition of rTPJ activity selectively impairs the ability to evaluate the rod's verticality when no contextual visual information, such as a frame surrounding the rod, is provided. Conversely, transient inhibition of V1-V3 selectively disrupts the ability to visually detect Gabor patch orientation. This anatomofunctional dissociation supports the idea that the rTPJ plays a causal role in integrating egocentric sensory information encoded in different reference systems (i.e., vestibular and somatic) to maintain an internal representation of verticality.
authors.affiliation: Department of Psychology, Sapienza University of Rome, Rome, Italy; IRCCS, Fondazione Santa Lucia, Rome, Italy; and francesca.fiori@uniroma1.it.
authors.forename: Francesca
authors.identifier: http://orcid.org/0000-0002-5437-1224
authors.initials: F
authors.lastname: Fiori
authors.affiliation: Department of Psychology, Sapienza University of Rome, Rome, Italy; IRCCS, Fondazione Santa Lucia, Rome, Italy; and.
authors.forename: Matteo
authors.initials: M
authors.lastname: Candidi
authors.affiliation: Department of Psychology, Sapienza University of Rome, Rome, Italy; IRCCS, Fondazione Santa Lucia, Rome, Italy; and.
authors.forename: Adriano
authors.initials: A
authors.lastname: Acciarino
authors.affiliation: Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Nicole
authors.initials: N
authors.lastname: David
authors.affiliation: Department of Psychology, Sapienza University of Rome, Rome, Italy; IRCCS, Fondazione Santa Lucia, Rome, Italy; and.
authors.forename: Salvatore Maria
authors.initials: SM
authors.lastname: Aglioti
mesh_terms: D000328:Adult; D019054:Evoked Potentials, Motor; D005260:Female; D006225:Hand / Q000294:innervation / Q000502:physiology; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology; D009949:Orientation / Q000502:physiology*; D010296:Parietal Lobe / Q000502:physiology*; D010775:Photic Stimulation; D013702:Temporal Lobe / Q000502:physiology*; D050781:Transcranial Magnetic Stimulation; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult
keywords: TMS; TPJ; multisensory integration; rod and frame