New findings and pathophysiology in attitude control through vestibular interoception

Abstract

Attitude control is associated with coordinated limb, body, head, and ocular movements through vestibular interoception. During straight walking, walking speed for velocities ranging from 1.2–1.8 m/s. Over this range of walking velocities, there is both translation and rotation of the head in the sagittal plane, reaching translational frequencies close to 2 Hz, peak vertical linear accelerations of 0.3–0.5 g, and peak pitch velocities of 15–22°/s. The magnitude and frequency of the pitch angular and vertical translational head movements are sufficient to activate both the angular and linear vestibulo-ocular (aVOR and lVOR) and vestibulo-collic (aVCR and lVCR) reflexes, which may play important roles in directing gaze and in stabilizing gait. In support of this, unilateral vestibular disease is associated with instability of gait, and astronauts, whose vestibular function has been adapted to microgravity, also experience difficulty when walking a curved path after flight. The purpose of this study was to infer a possible role for the vestibular interoception in producing head and eye movements in three dimensions as the body moves in space.