title: Visual-vestibular processing in the human Sylvian fissure.
abstract: Unlike other sensory systems, the cortical organization of the human vestibular system is not well established. A central role is assumed for the region of the posterior Sylvian fissure, close to the posterior insula. At this site, activation during vestibular stimulation has been observed in previous imaging studies and labeled as the parieto-insular vestibular cortex area (PIVC). However, vestibular responses are found in other parts of the Sylvian fissure as well, including a region that is referred to as the posterior insular cortex (PIC). The anatomical and functional relationship between PIC and PIVC is still poorly understood, because both areas have never been compared in the same participants. Therefore, to better understand the apparently more complex organization of vestibular cortex in the Sylvian fissure, we employed caloric and visual object motion stimuli during functional magnetic resonance imaging and compared location and function of PIVC and PIC in the same participants. Both regions responded to caloric vestibular stimulation, but only the activation pattern in right PIVC reliably represented the direction of the caloric stimulus. Conversely, activity in PIVC was suppressed during stimulation with visual object motion, whereas PIC showed activation. Area PIC is located at a more posterior site in the Sylvian fissure than PIVC. Our results suggest that PIVC and PIC should be considered separate areas in the vestibular Sylvian network, both in terms of location and function.
authors.affiliation: Department of Psychological and Brain Sciences, Dartmouth College, Hanover, New Hampshire.
authors.forename: Sebastian M
authors.initials: SM
authors.lastname: Frank
authors.affiliation: Institute of Experimental Psychology, University of Regensburg, Regensburg, Germany; and.
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Wirth
authors.affiliation: Institute of Experimental Psychology, University of Regensburg, Regensburg, Germany; and mark.greenlee@ur.de.
authors.forename: Mark W
authors.initials: MW
authors.lastname: Greenlee
mesh_terms: D000328:Adult; D000344:Afferent Pathways / Q000502:physiology*; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000000981:diagnostic imaging / Q000502:physiology*; D005260:Female; D007839:Functional Laterality; D006358:Hot Temperature; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009039:Motion Perception / Q000502:physiology; D015999:Multivariate Analysis; D010100:Oxygen / Q000097:blood; D010775:Photic Stimulation; D010812:Physical Stimulation; D014722:Vestibule, Labyrinth / Q000502:physiology*; D055815:Young Adult
chemical_list: D010100:Oxygen
keywords: Sylvian fissure; area PIC; area PIVC; caloric vestibular stimulation; vestibular cortex