Mizusawa Hiroki, Jono Yasutomo, Iwata Yasuyuki, Kinoshita Atsushi, Hiraoka Koichi
Graduate School of Comprehensive Rehabilitation, Osaka Prefecture University, Habikino, Osaka, Japan.
College of Health and Human Sciences, Osaka Prefecture University, Habikino, Osaka, Japan.
Hum Mov Sci. 2017 Apr;52:1-16. doi: 10.1016/j.humov.2017.01.003. Epub 2017 Jan 13.
The purpose of this study was to elucidate whether the anticipatory postural adjustment (APA) and focal step movement of gait initiation are produced as a single process or different processes and whether the APA receives an inhibitory drive from the ongoing stop process of gait initiation. Healthy humans initiated gait in response to a first visual cue that instructed the initial swing leg. In some trials, a switch or stop cue was also provided after the first cue. When the stop cue was provided, participants withheld gait initiation. When the switch cue was provided, participants immediately switched the initial swing leg. In both the stop and switch tasks, the APA in response to the first cue, represented by the S1 period of the displacement of the center of pressure, appeared in more than half of the trials in which the withholding of gait initiation or switching of the initial swing leg was successfully completed. These findings indicate that the APA and focal step movement of gait initiation are produced as a dual process. In trials in which the APA in response to the first cue appeared, the amplitude and duration of the APA were decreased when the participants switched the initial swing leg or withheld gait initiation. This finding indicates that the ongoing stop process of gait initiation produces an inhibitory drive over the APA. The decreases in the amplitude and duration of the APA during the switching of the initial swing leg were similar to those during the withholding of gait initiation; moreover, the decreases during the switching of the initial swing leg were positively correlated with the decreases during the withholding of gait initiation. Thus, the stop processes during switching the initial swing leg and withholding gait initiation likely share a common inhibitory mechanism over the APA.
本研究的目的是阐明步态起始的预期姿势调整（APA）和焦点步移动是作为一个单一过程还是不同过程产生的，以及APA是否受到步态起始正在进行的停止过程的抑制驱动。健康人根据指示初始摆动腿的第一个视觉提示开始步态。在一些试验中，在第一个提示之后还提供了切换或停止提示。当提供停止提示时，参与者抑制步态起始。当提供切换提示时，参与者立即切换初始摆动腿。在停止和切换任务中，以压力中心位移的S1期表示的对第一个提示的APA，出现在超过一半的成功完成步态起始抑制或初始摆动腿切换的试验中。这些发现表明步态起始的APA和焦点步移动是作为一个双重过程产生的。在对第一个提示的APA出现的试验中，当参与者切换初始摆动腿或抑制步态起始时，APA的幅度和持续时间会减小。这一发现表明步态起始正在进行的停止过程对APA产生抑制驱动。初始摆动腿切换期间APA幅度和持续时间的减小与步态起始抑制期间的减小相似；此外，初始摆动腿切换期间的减小与步态起始抑制期间的减小呈正相关。因此，初始摆动腿切换和步态起始抑制期间的停止过程可能对APA共享一种共同的抑制机制。
