Sternad Dagmar, de Rugy Aymar, Pataky Todd, Dean William J
Department of Kinesiology, The Pennsylvania State University, 266 Recreation Building, University Park, PA 16802, USA.
Exp Brain Res. 2002 Nov;147(2):162-74. doi: 10.1007/s00221-002-1219-1. Epub 2002 Sep 20.
This study investigates a complex task in which rhythmic and discrete components have to be combined in single-joint elbow rotations. While previous studies of similar tasks already reported that the initiation of the discrete movement is constrained to a particular phase window of the ongoing rhythmic movement, interpretations have remained contradictory due to differences in paradigms, oscillation frequencies, and data analysis techniques. The present study aims to clarify these findings and further elucidate the bidirectional nature of the interaction between discrete and rhythmic components. Participants performed single-degree-of-freedom elbow oscillatory movements at five prescribed periods (400, 500, 600, 800, 1,000 ms). They rapidly switched the midpoint of oscillation to a second target after an auditory signal that occurred at a random phase of the oscillation, without stopping the oscillation. Results confirmed that the phase of the discrete movement initiation is highly constrained with respect to the oscillation period. Further, the duration, peak velocity, and the overshoot of the discrete movement varied systematically with the period of the rhythmic movement. Effects of the discrete-onto-rhythmic component were seen in a phase resetting of the oscillation and a systematic acceleration after the discrete movement, which also varied as a function of the oscillation period. These results are interpreted in terms of an inhibitory bidirectional coupling between discrete and rhythmic movement. The interaction between discrete and rhythmic movement elements is discussed in comparison to sequential and gating processes suggested previously.
本研究调查了一项复杂任务，即在单关节肘部旋转中必须将节律性和离散性成分结合起来。虽然先前对类似任务的研究已经报道离散运动的启动被限制在正在进行的节律性运动的特定相位窗口内，但由于范式、振荡频率和数据分析技术的差异，解释仍然相互矛盾。本研究旨在澄清这些发现，并进一步阐明离散成分和节律性成分之间相互作用的双向性质。参与者在五个规定周期（400、500、600、800、1000毫秒）下进行单自由度肘部振荡运动。在振荡的随机相位出现听觉信号后，他们迅速将振荡中点切换到第二个目标，而不停止振荡。结果证实，离散运动启动的相位相对于振荡周期受到高度限制。此外，离散运动的持续时间、峰值速度和超调量随节律性运动的周期而系统变化。离散成分对节律性成分的影响表现为振荡的相位重置以及离散运动后的系统加速，这也随振荡周期而变化。这些结果被解释为离散运动和节律性运动之间的抑制性双向耦合。与先前提出的顺序和门控过程相比，讨论了离散运动和节律性运动元素之间的相互作用。
