title: Spatio-temporal pattern of vestibular information processing after brief caloric stimulation.
abstract: Processing of vestibular information at the cortical and subcortical level is essential for head and body orientation in space and self-motion perception, but little is known about the neural dynamics of the brain regions of the vestibular system involved in this task. Neuroimaging studies using both galvanic and caloric stimulation have shown that several distinct cortical and subcortical structures can be activated during vestibular information processing. The insular cortex has been often targeted and presented as the central hub of the vestibular cortical system. Since very short pulses of cold water ear irrigation can generate a strong and prolonged vestibular response and a nystagmus, we explored the effects of this type of caloric stimulation for assessing the blood-oxygen-level-dependent (BOLD) dynamics of neural vestibular processing in a whole-brain event-related functional magnetic resonance imaging (fMRI) experiment. We evaluated the spatial layout and the temporal dynamics of the activated cortical and subcortical regions in time-locking with the instant of injection and were able to extract a robust pattern of neural activity involving the contra-lateral insular cortex, the thalamus, the brainstem and the cerebellum. No significant correlation with the temporal envelope of the nystagmus was found. The temporal analysis of the activation profiles highlighted a significantly longer duration of the evoked BOLD activity in the brainstem compared to the insular cortex suggesting a functional de-coupling between cortical and subcortical activity during the vestibular response.
authors.affiliation: Department of Neuroscience, University of Naples Federico II, Naples, Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Marcelli
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Esposito
authors.forename: Adriana
authors.initials: A
authors.lastname: Aragri
authors.forename: Teresa
authors.initials: T
authors.lastname: Furia
authors.forename: Pasquale
authors.initials: P
authors.lastname: Riccardi
authors.forename: Michela
authors.initials: M
authors.lastname: Tosetti
authors.forename: Laura
authors.initials: L
authors.lastname: Biagi
authors.forename: Elio
authors.initials: E
authors.lastname: Marciano
authors.forename: Francesco
authors.initials: F
authors.lastname: Di Salle
mesh_terms: D000328:Adult; D001931:Brain Mapping / Q000379:methods*; D002150:Caloric Tests; D002540:Cerebral Cortex / Q000502:physiology*; D003080:Cold Temperature; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009415:Nerve Net / Q000502:physiology*; D010812:Physical Stimulation / Q000379:methods; D014722:Vestibule, Labyrinth / Q000502:physiology*