Department of Sport and Exercise Science, The University of Auckland, Auckland, New Zealand.
J Neurophysiol. 2012 Sep;108(5):1492-500. doi: 10.1152/jn.01184.2011. Epub 2012 Jun 13.
The ability to prevent unwanted movement is fundamental to human behavior. When healthy adults must prevent a subset of prepared actions, execution of the remaining response is markedly delayed. We hypothesized that the delay may be sensitive to the degree of similarity between the prevented and continued actions. Fifteen healthy participants performed an anticipatory response inhibition task that required bilateral index finger extension or thumb abduction with homogeneous digit pairings, or a heterogeneous pairing of a combination of the two movements. We expected that the uncoupling of responses required for selective movement prevention would be more difficult with homogeneous (same digit, homologous muscles) than heterogeneous pairings (different digits, nonhomologous muscles). Measures of response times (and asynchrony between digits) during action execution, stopping performance, and electromyography from EIP (index finger extension) and APB (thumb abduction) were analyzed. As expected, selective trials produced a delay in the remaining movement compared with execution trials. Successful performance in the selective condition occurred via suppression of the entire prepared response and subsequent selective reinitiation of the remaining component. Importantly, the delayed reinitiation of motor output was sensitive to the degree of similarity between responses, occurring later but at a faster rate with homogeneous digits. There were persistent aftereffects from the selective condition on the motor system, which indicated greater levels of inhibition and a higher gain were necessary to successfully perform selective trials with homogeneous pairings. Overall, the results support a model of inhibition of a unitary response and selective reinitiation, rather than selective inhibition.
防止不必要运动的能力是人类行为的基础。当健康成年人必须防止一系列预备动作时，其余反应的执行会明显延迟。我们假设这种延迟可能对被阻止和继续的动作之间的相似程度敏感。十五名健康参与者进行了一项预期反应抑制任务，该任务需要双侧食指伸展或拇指外展，具有同质的数字配对，或两种运动的组合的异质配对。我们预计，对于选择性运动预防所需的反应解耦，同质（相同数字，同源肌肉）配对比异质（不同数字，非同源肌肉）配对更困难。在执行动作、停止表现和来自 EIP（食指伸展）和 APB（拇指外展）的肌电图时，分析了反应时间（以及数字之间的异步性）的测量值。正如预期的那样，选择性试验与执行试验相比，剩余运动产生了延迟。在选择性条件下的成功表现是通过抑制整个预备反应并随后选择性地重新启动剩余组件来实现的。重要的是，运动输出的延迟重新启动对反应之间的相似程度敏感，同质数字的延迟时间更长，但速度更快。选择性条件对运动系统有持久的后效，这表明需要更高水平的抑制和更高的增益才能成功地进行同质配对的选择性试验。总体而言，结果支持了一种抑制单一反应和选择性重新启动的模型，而不是选择性抑制。
