Radboud University, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands.
Department of Human Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.
J Neurophysiol. 2019 Sep 1;122(3):947-957. doi: 10.1152/jn.00616.2018. Epub 2019 Jul 17.
Humans quickly and sophisticatedly correct their movements in response to changes in the world, such as when reaching to a target that abruptly changes its location. The vigor of these movement corrections is time-dependent, increasing if the time left to make the correction decreases, which can be explained by optimal feedback control (OFC) theory as an increase of optimal feedback gains. It is unknown whether corrections for changes in the world are as sophisticated under full-body motion. For successful visually probed motor corrections during full-body motion, not only the motion of the hand relative to the body needs to be taken into account, but also the motion of the hand in the world should be considered, because their relative positions are changing. Here, in two experiments, we show that visuomotor feedback corrections in response to target jumps are more vigorous for faster passive full-body translational acceleration than for slower acceleration, suggesting that vestibular information modulates visuomotor feedback gains. Interestingly, these corrections do not demonstrate the time-dependent characteristics that body-stationary visuomotor feedback gains typically show, such that an optimal feedback control model fell short to explain them. We further show that the vigor of corrections generally decreased over the course of trials within the experiment, suggesting that the sensorimotor system adjusted its gains when learning to integrate the vestibular input into hand motor control. Vestibular information is used in the control of reaching movements to world-stationary visual targets, while the body moves. Here, we show that vestibular information also modulates the corrective reach responses when the target changes position during the body motion: visuomotor feedback gains increase for faster body acceleration. Our results suggest that vestibular information is integrated into fast visuomotor control of reaching movements.
人类能够迅速而精细地调整自己的动作以适应世界的变化，例如在伸手去抓一个突然改变位置的目标时。这些动作校正的力度与时间有关，如果留给校正的时间减少，校正力度就会增加，这可以用最优反馈控制（OFC）理论来解释，即最优反馈增益增加。目前尚不清楚在全身运动的情况下，对世界变化的校正是否同样精细。为了在全身运动中成功地进行视觉探测的运动校正，不仅需要考虑手相对于身体的运动，还需要考虑手在世界中的运动，因为它们的相对位置在不断变化。在这里，我们通过两个实验表明，相对于较慢的被动全身平移加速度，更快的被动全身平移加速度会使视觉运动反馈校正更加有力，这表明前庭信息调节了视觉运动反馈增益。有趣的是，这些校正并没有表现出像身体静止的视觉运动反馈增益那样的时间依赖性特征，因此最优反馈控制模型无法解释这些特征。我们进一步表明，在实验过程中，校正的力度通常会随着试验的进行而逐渐降低，这表明当传感器系统学习将前庭输入整合到手的运动控制中时，它会调整增益。前庭信息用于控制身体运动时到达静止于世界的视觉目标的运动，在这里，我们表明前庭信息在身体运动期间目标位置改变时也会调节校正的伸手反应：身体加速度越快，视觉运动反馈增益越大。我们的结果表明，前庭信息被整合到快速的视觉运动控制中，用于到达运动。
