MacDonald Hayley J, McMorland Angus J C, Stinear Cathy M, Coxon James P, Byblow Winston D
Movement Neuroscience Laboratory, Department of Sport & Exercise Science, University of Auckland, Auckland, 1142, New Zealand.
Centre for Brain Research, University of Auckland, Auckland, 1142, New Zealand.
PLoS One. 2017 Jan 13;12(1):e0169320. doi: 10.1371/journal.pone.0169320. eCollection 2017.
Reactive response inhibition (RI) is the cancellation of a prepared response when it is no longer appropriate. Selectivity of RI can be examined by cueing the cancellation of one component of a prepared multi-component response. This substantially delays execution of other components. There is debate regarding whether this response delay is due to a selective neural mechanism. Here we propose a computational activation threshold model (ATM) and test it against a classical "horse-race" model using behavioural and neurophysiological data from partial RI experiments. The models comprise both facilitatory and inhibitory processes that compete upstream of motor output regions. Summary statistics (means and standard deviations) of predicted muscular and neurophysiological data were fit in both models to equivalent experimental measures by minimizing a Pearson Chi-square statistic. The ATM best captured behavioural and neurophysiological dynamics of partial RI. The ATM demonstrated that the observed modulation of corticomotor excitability during partial RI can be explained by nonselective inhibition of the prepared response. The inhibition raised the activation threshold to a level that could not be reached by the original response. This was necessarily followed by an additional phase of facilitation representing a secondary activation process in order to reach the new inhibition threshold and initiate the executed component of the response. The ATM offers a mechanistic description of the neural events underlying RI, in which partial movement cancellation results from a nonselective inhibitory event followed by subsequent initiation of a new response. The ATM provides a framework for considering and exploring the neuroanatomical constraints that underlie RI.
反应性反应抑制（RI）是指当准备好的反应不再适当时将其取消。可以通过提示取消准备好的多成分反应的一个成分来检验RI的选择性。这会显著延迟其他成分的执行。关于这种反应延迟是否归因于选择性神经机制存在争议。在此，我们提出一种计算激活阈值模型（ATM），并使用来自部分RI实验的行为和神经生理学数据，将其与经典的“赛马”模型进行对比测试。这些模型包括在运动输出区域上游相互竞争的促进和抑制过程。通过最小化皮尔逊卡方统计量，将两个模型中预测的肌肉和神经生理学数据的汇总统计量（均值和标准差）与等效的实验测量值进行拟合。ATM最能捕捉部分RI的行为和神经生理动力学。ATM表明，在部分RI期间观察到的皮质运动兴奋性调制可以通过对准备好的反应的非选择性抑制来解释。这种抑制将激活阈值提高到原始反应无法达到的水平。随后必然会有一个额外的促进阶段，代表一个二次激活过程，以便达到新的抑制阈值并启动反应的执行成分。ATM提供了对RI背后神经事件的机制描述，其中部分运动取消是由非选择性抑制事件导致的，随后启动新的反应。ATM为考虑和探索RI背后的神经解剖学限制提供了一个框架。
