VESTIBULAR PERCEPTION OF PASSIVE WHOLE-BODY ROTATION ABOUT HORIZONTALAND VERTICAL AXES IN HUMANS - GOAL-DIRECTED VESTIBULOOCULAR REFLEX AND VESTIBULAR MEMORY-CONTINGENT SACCADES

This study was aimed at complementing the existing knowledge about ves tibular perception of self-motion in humans. Both goal-directed vestib ulo-ocular reflex and vestibular memory-contingent saccade (VMCS) task s were used, respectively as concurrent and retrospective magnitude es timators for passive whole-body rotation. Rotations were applied about the earth-vertical and earth-horizontal axes to study the effect of t he otolith signal in self-rotation evaluation, and both in yaw and pit ch to examine the horizontal and vertical semi-circular canals. Two di fferent magnitudes of constant angular acceleration (50-degrees/s2 and 100-degrees/s2) were used. The main findings were (1) strong correlat ion between both oculomotor responses of both tasks, (2) greater accur acy with rotations about the earth-vertical than the earth: -horizonta l axis, (3) greater accuracy for yaw than for pitch rotations, (4) gre ater accuracy for high acceleration than for low, and (5) no effect of the delay (2 s or 12 s) in the VMCS task. Adequacy of both tasks as s ubjective magnitude estimators of vestibular perception of self-motion is discussed.