Saccade suppression exerts global effects on the motor system
Saccade suppression exerts global effects on the motor system
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DOI：
10.1152/jn.00229.2013
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发表时间：
2013-08-01
影响因子：
2.5
通讯作者：
Aron, Adam R.
中科院分区：
文献类型：
--
作者：
Wessel, Jan R.;Reynoso, H. Sequoyah;Aron, Adam R.
停止不适当的眼球运动是一种认知控制功能，可以让人类在需要注意力集中的情况下表现良好。停止信号任务是这一行为的实验模型。参与者发起向目标的扫视，如果出现停止信号，偶尔必须尝试停止即将到来的扫视。先前对肢体运动(手、腿)和语言的研究表明，快速停止动作会导致运动系统的明显整体抑制，在M1的经颅磁刺激(TMS)研究中，以任务无关效应器的皮质脊髓兴奋性(CSE)为指标。在这里，我们以高时间精度测量手部的CSE，当参与者进行眼跳时，当他们成功地和不成功地停止这些眼跳时，他们对停止信号做出反应。我们发现，在估计的眼跳被成功停止的时间之前50毫秒，手部的CSE降低，这与任务无关。这表明，快速停止眼球运动也会产生全球运动效应。我们推测，这是因为快速停止眼球运动，就像骨骼运动一样，可能是通过输入到基底神经节的丘脑底核实现的，推测对丘脑皮质驱动具有广泛的抑制作用。由于最近的研究表明，这种抑制效应也可能影响非运动表征，目前的发现指出了某些类型分心的可能机制基础：突然开始的刺激会通过产生全局运动和非运动效应来中断正在进行的加工。
Stopping inappropriate eye movements is a cognitive control function that allows humans to perform well in situations that demand attentional focus. The stop-signal task is an experimental model for this behavior. Participants initiate a saccade toward a target and occasionally have to try to stop the impending saccade if a stop signal occurs. Prior research using a version of this paradigm for limb movements (hand, leg) as well as for speech has shown that rapidly stopping action leads to apparently global suppression of the motor system, as indexed by the corticospinal excitability (CSE) of task-unrelated effectors in studies with transcranial magnetic stimulation (TMS) of M1. Here we measured CSE from the hand with high temporal precision while participants made saccades and while they successfully and unsuccessfully stopped these saccades in response to a stop signal. We showed that 50 ms before the estimated time at which a saccade is successfully stopped there was reduced CSE for the hand, which was task irrelevant. This shows that rapidly stopping eye movements also has global motor effects. We speculate that this arises because rapidly stopping eye movements, like skeleto-motor movements, is possibly achieved via input to the subthalamic nucleus of the basal ganglia, with a putatively broad suppressive effect on thalamocortical drive. Since recent studies suggest that this suppressive effect could also impact nonmotor representations, the present finding points to a possible mechanistic basis for some kinds of distractibility: abrupt-onset stimuli will interrupt ongoing processing by generating global motor and nonmotor effects.