Gimmon Yoav, Migliaccio Americo A, Todd Christopher J, Figtree William V C, Schubert Michael C
Laboratory of Vestibular NeuroAdaptation, Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine , Baltimore, Maryland.
Balance and Vision Laboratory, Neuroscience Research Australia, Sydney, New South Wales , Australia.
J Neurophysiol. 2018 Oct 1;120(4):1496-1504. doi: 10.1152/jn.00134.2018. Epub 2018 Jun 27.
The healthy vestibulo-ocular reflex (VOR) ensures that images remain on the fovea of the retina during head rotation to maintain stable vision. VOR behavior can be measured as a summation of linear and nonlinear properties although it is unknown whether asymmetric VOR adaptation can be performed synchronously in humans. The purpose of the present study is twofold. First, examine whether the right and left VOR gains can be synchronously adapted in opposing directions. Second, to investigate whether the adaptation context transfers between both sides. Three separate VOR adaptation sessions were randomized such that the VOR was adapted Up-bilaterally, Down-bilaterally, or Mixed (one side up, opposite side down). Ten healthy subjects completed the study. Subjects were tested while seated upright, 1 meter in front of a wall in complete dark. Each subject made active (self-generated) head impulse rotations for 15 min while viewing a gradually increasing amount of retinal slip. VOR training demand changed by 10% every 90 s. The VOR changed significantly for all training conditions. No significant differences in the magnitude of VOR gain changes between training conditions were found. The human VOR can be simultaneously driven in opposite directions. The similar magnitude of VOR gain changes across training conditions suggests functionally independent VOR circuits for each side of head rotation that mediate simultaneous and opposing VOR adaptations. NEW & NOTEWORTHY Our results indicate that humans have the adaptive capacity for concurrent and opposing directions of vestibulo-ocular reflex (VOR) motor learning. Context specificity of VOR adaptation is dependent on the error signal being unilateral or bilateral, which we illustrate via a lack of VOR gain transfer using unique adaptive demands.
健康的前庭眼反射（VOR）可确保在头部旋转期间图像保持在视网膜中央凹上，以维持稳定的视力。VOR行为可作为线性和非线性特性的总和来测量，尽管尚不清楚人类是否能同步进行不对称的VOR适应。本研究的目的有两个。第一，研究左右VOR增益是否能在相反方向上同步适应。第二，研究适应背景是否能在两侧之间转移。三个独立的VOR适应训练环节被随机安排，使得VOR分别进行双侧向上、双侧向下或混合（一侧向上，另一侧向下）适应。十名健康受试者完成了该研究。受试者在完全黑暗中直立坐在距离墙壁1米处接受测试。每个受试者在观看逐渐增加的视网膜滑移量时进行15分钟的主动（自我产生）头部脉冲旋转。VOR训练需求每90秒变化10%。在所有训练条件下，VOR均有显著变化。未发现训练条件之间VOR增益变化幅度的显著差异。人类的VOR可以同时在相反方向上被驱动。不同训练条件下VOR增益变化幅度相似，这表明头部旋转每一侧的VOR回路在功能上是独立的，可介导同时且相反的VOR适应。新发现与值得注意之处我们的结果表明，人类在前庭眼反射（VOR）运动学习中具有同时进行相反方向适应的能力。VOR适应的背景特异性取决于误差信号是单侧还是双侧的，我们通过使用独特的适应需求缺乏VOR增益转移来说明这一点。
