title: Modulation of cortical vestibular processing by somatosensory inputs in the posterior insula.
abstract: OBJECTIVE
  To study the mechanism of somatosensory-vestibular interactions, this study examined the effects of somatosensory inputs on body sway induced by galvanic vestibular stimulation (GVS) in healthy participants and persons with brain injury in the posterior insula, a region constituting a part of the parietoinsular vestibular cortex.
  
  
  METHODS
  This study adopted an experimental, controlled, repeated measures design.
  
  
  METHODS
  Participants were 11 healthy individuals, two persons with unilateral posterior insular injury and two age-matched controls. Bipolar GVS was applied to the mastoid processes while participants were sitting with their eyes closed, either lightly touching a stable surface with their index finger or not touching the surface with their index finger.
  
  
  RESULTS
  In healthy participants, tilting was greater with right hemispheric stimulation than with left hemispheric stimulation. Moreover, with right hemispheric stimulation, tilting was greater with a right finger touch than with no touch. The person with right-brain injury showed tilting induced by GVS; however, finger touch had no modulatory effect. In contrast, finger touch enhanced tilting in the person with left-brain injury.
  
  
  CONCLUSIONS
  These preliminary results are discussed in light of a hypothesis of right hemispheric dominance of somatosensory-vestibular interactions in the posterior insula.
authors.affiliation: Laboratory for Symbolic Cognitive Development, RIKEN Brain Science Institute , Wako , Japan and.
authors.forename: Teruo
authors.initials: T
authors.lastname: Hashimoto
authors.forename: Miki
authors.initials: M
authors.lastname: Taoka
authors.forename: Shigeru
authors.initials: S
authors.lastname: Obayashi
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Hara
authors.forename: Michio
authors.initials: M
authors.lastname: Tanaka
authors.forename: Atsushi
authors.initials: A
authors.lastname: Iriki
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001930:Brain Injuries / Q000503:physiopathology*; D016022:Case-Control Studies; D002540:Cerebral Cortex; D004558:Electric Stimulation; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D008875:Middle Aged; D013003:Somatosensory Cortex / Q000503:physiopathology*; D014110:Touch; D055698:Touch Perception; D014722:Vestibule, Labyrinth