Department of Physical Education and Sport Sciences, University of Limerick, Limerick, Ireland.
Lero, Irish Software Research Centre, University of Limerick, Limerick, Ireland.
Exp Brain Res. 2019 Sep;237(9):2185-2196. doi: 10.1007/s00221-019-05571-6. Epub 2019 Jun 18.
Our recent work demonstrated that vision can recalibrate the vestibular signal used to re-establish equilibrium following a platform perturbation. Here, we investigate whether vision provided during a platform perturbation can recalibrate the use of vestibular reafference during the dynamic phase of the perturbation response. Dynamic postural responses were examined during a series of five forward perturbations to the body, while galvanic vestibular stimulation (GVS) selectively altered vestibular feedback and LCD occlusion spectacles controlled visual availability. Responses with and without vision were compared. The presence of GVS caused 1.78 ± 0.19 cm of medio-lateral (ML) body motion toward the anode during the initial 3 s of the dynamic postural response across perturbations. This dynamic ML response was attenuated across perturbations 1-3 independent of visual availability, resulting in a significant reduction of ML center of mass and pressure deviations (p < 0.01, ƞ = 0.27). That is, the vestibular influence on the ML perturbation response could be altered but vision was not necessary for this adaptation. After removing GVS, the ML response component reversed in direction toward the cathode with a magnitude that was not significantly different to the amount of response attenuation seen when GVS was present (- 0.95 ± 0.19 cm; p = 0.99, ƞ = 0.00). This suggested that the use of a GVS-altered vestibular signal during dynamic perturbation responses could be recalibrated, but that visual feedback was likely not responsible. Alternative mechanisms to explain the recalibration process are discussed.
我们最近的工作表明，视觉可以重新校准前庭信号，用于在平台扰动后重新建立平衡。在这里，我们研究了在平台扰动期间提供的视觉是否可以重新校准前庭反馈在扰动响应的动态阶段的使用。在一系列五次向身体施加向前的扰动过程中，检查了动态姿势反应，同时，电流前庭刺激 (GVS) 选择性地改变了前庭反馈，而液晶显示器遮挡眼镜控制了视觉可用性。比较了有和没有视觉的反应。在动态姿势反应的最初 3 秒内，GVS 的存在导致了阳极侧的身体向阳极方向的 1.78 ± 0.19 cm 的 ML 运动。这种动态 ML 反应在扰动 1-3 之间独立于视觉可用性而减弱，导致 ML 质心和压力偏差显著减小 (p < 0.01，ƞ = 0.27)。也就是说，前庭对 ML 扰动反应的影响可以改变，但这种适应并不需要视觉。在去除 GVS 后，ML 响应分量的方向向阴极反转，其幅度与 GVS 存在时观察到的响应衰减量没有显著差异 (-0.95 ± 0.19 cm; p = 0.99，ƞ = 0.00)。这表明，在动态扰动响应期间使用 GVS 改变的前庭信号可以重新校准，但视觉反馈可能不是原因。讨论了解释重新校准过程的替代机制。
