Antero-Posterior vs. Lateral Vestibular Input Processing in Human Visual Cortex
Résumé
Visuo-vestibular integration is crucial for locomotion, yet the cortical mechanismsinvolved remain poorly understood. We combined binaural monopolar galvanic vestibularstimulation (GVS) and functional magnetic resonance imaging (fMRI) to characterize thecortical networks activated during antero-posterior and lateral stimulations in humans.We focused on functional areas that selectively respond to egomotion-consistent opticflow patterns: the human middle temporal complex (hMT+), V6, the ventral intraparietal(VIP) area, the cingulate sulcus visual (CSv) area and the posterior insular cortex (PIC).Areas hMT+, CSv, and PIC were equivalently responsive during lateral and antero-posterior GVS while areas VIP and V6 were highly activated during antero-posteriorGVS, but remained silent during lateral GVS. Using psychophysiological interaction (PPI)analyses, we confirmed that a cortical network including areas V6 and VIP is engagedduring antero-posterior GVS. Our results suggest that V6 and VIP play a specific role inprocessing multisensory signals specific to locomotion during navigation
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