Department of Human Physiology and Institute of Neuroscience, University of Oregon, Eugene, OR 97403-1240, USA.
J Neurosci. 2011 Jul 6;31(27):10019-22. doi: 10.1523/JNEUROSCI.0037-11.2011.
Accurate motor execution is achieved by estimating future sensory states via a forward model of limb dynamics. In the current experiment, we probed the time course over which state estimation evolves during movement planning by combining a bimanual arm crossing movement with a temporal order judgment (TOJ) task. Human participants judged which of two successive vibrotactile stimuli delivered to each index finger arrived first as they were preparing to either cross or uncross their hands. TOJ error rate was found to systematically vary in a time- and direction-dependent manner. When planning to cross the hands, error rate systematically increased as the vibrotactile stimuli were delivered closer in time to the onset of the movement. By contrast, planning to uncross the hands led to a gradual reduction in error rate as movement planning progressed. In both cases, these changes occurred before the actual alteration in hand configuration. We suggest that these systematic changes in error represent an interaction between the evolving state estimation processes and decisions regarding the timing of successive events.
准确的运动执行是通过对肢体动力学的前向模型来估计未来的感觉状态来实现的。在当前的实验中，我们通过将双臂交叉运动与时间顺序判断（TOJ）任务相结合，探究了在运动规划过程中状态估计随时间变化的过程。当参与者准备双手交叉或分开时，他们判断两个相继的振动刺激分别传递到每个食指的时间。发现 TOJ 错误率以时间和方向依赖的方式系统地变化。当计划双手交叉时，随着振动刺激与运动开始的时间间隔更近，错误率系统地增加。相比之下，计划双手分开时，随着运动计划的进行，错误率逐渐降低。在这两种情况下，这些变化都发生在手型实际改变之前。我们认为，错误率的这些系统变化代表了不断发展的状态估计过程和关于相继事件时间的决策之间的相互作用。
