Cerebral Hemodynamic Responses to the Sensory Conflict Between Visual and Rotary Vestibular Stimuli: An Analysis With a Multichannel Near-Infrared Spectroscopy (NIRS) System

Nghia Trong Nguyen; Hiromasa Takakura; Hisao Nishijo; Naoko Ueda; Shinsuke Ito; Michiro Fujisaka; Katsuichi Akaogi; Hideo Shojaku

doi:10.3389/fnhum.2020.00125

Cerebral Hemodynamic Responses to the Sensory Conflict Between Visual and Rotary Vestibular Stimuli: An Analysis With a Multichannel Near-Infrared Spectroscopy (NIRS) System

Front Hum Neurosci. 2020 Apr 21:14:125. doi: 10.3389/fnhum.2020.00125. eCollection 2020.

Authors

Nghia Trong Nguyen¹, Hiromasa Takakura¹, Hisao Nishijo², Naoko Ueda¹, Shinsuke Ito¹, Michiro Fujisaka¹, Katsuichi Akaogi³, Hideo Shojaku¹

Affiliations

¹ Department of Otorhinolaryngology, Head and Neck Surgery, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan.
² System Emotional Science Laboratory, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan.
³ Department of Otorhinolaryngology, Toyama Red Cross Hospital, Toyama, Japan.

Abstract

Sensory conflict among visual, vestibular, and somatosensory information induces vertiginous sensation and postural instability. To elucidate the cognitive mechanisms of the integration between the visual and vestibular cues in humans, we analyzed the cortical hemodynamic responses during sensory conflict between visual and horizontal rotatory vestibular stimulation using a multichannel near-infrared spectroscopy (NIRS) system. The subjects sat on a rotatory chair that was accelerated at 3°/s² for 20 s to the right or left, kept rotating at 60°/s for 80 s, and then decelerated at 3°/s² for 20 s. The subjects were instructed to watch white stripes projected on a screen surrounding the chair during the acceleration and deceleration periods. The white stripes moved in two ways; in the "congruent" condition, the stripes moved in the opposite direction of chair rotation at 3°/s² (i.e., natural visual stimulation), whereas in the "incongruent" condition, the stripes moved in the same direction of chair rotation at 3°/s² (i.e., conflicted visual stimulation). The cortical hemodynamic activity was recorded from the bilateral temporoparietal regions. Statistical analyses using NIRS-SPM software indicated that hemodynamic activity increased in the bilateral temporoparietal junctions (TPJs) and human MT+ complex, including the medial temporal (MT) area and medial superior temporal (MST) area in the incongruent condition. Furthermore, the subjective strength of the vertiginous sensation was negatively correlated with hemodynamic activity in the dorsal part of the supramarginal gyrus (SMG) in and around the intraparietal sulcus (IPS). These results suggest that sensory conflict between the visual and vestibular stimuli promotes cortical cognitive processes in the cortical network consisting of the TPJ, the medial temporal gyrus (MTG), and IPS, which might contribute to self-motion perception to maintain a sense of balance or equilibrioception during sensory conflict.

Keywords: NIRS; intraparietal sulcus; medial superior temporal area; sensory conflict; temporoparietal junctions; vestibular cortices.