Premovement suppression of corticospinal excitability may be a necessary part of movement preparation
Premovement suppression of corticospinal excitability may be a necessary part of movement preparation
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运动前抑制皮质脊髓兴奋性可能是运动准备的必要部分
DOI：
10.1101/470153
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Ibáñez J
中科院分区：
文献类型：
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作者：
Ibáñez J
在反应时间（RT）任务中，皮质脊髓兴奋性（CSE）在运动之前上升。这之前是一个矛盾的减少CSE，当时间的命令（“GO”）刺激是相对可预测的。由于RT任务强调反应速度，因此无法区分减少的CSE是否反映了抑制准备动作的机制，或者它是否是运动准备的固有部分。为了解决这个问题，我们使用经颅磁刺激（TMS）来估计1）RT运动之前的CSE变化; 2）与可预测信号同步的运动（预测定时或PT运动）;和3）自定步调的运动。结果表明，CSE在所有三种情况下都以类似的时间曲线下降，这表明它反映了休息和运动之间过渡的先前未识别的状态。虽然TMS显示所有运动中CSE降低，但TMS脉冲本身对运动时间有不同的影响。在运动时间之前给予TMS ~200 ms加速RT和自主节奏运动的发作，这表明它们的启动取决于一种可以由外部事件调节的触发形式。相反，PT运动并没有表现出这种效果，这表明使用不同的触发策略优先考虑内部事件。
In reaction time (RT) tasks corticospinal excitability (CSE) rises just prior to movement. This is preceded by a paradoxical reduction in CSE, when the time of the imperative (“GO”) stimulus is relatively predictable. Because RT tasks emphasise speed of response, it is impossible to distinguish whether reduced CSE reflects a mechanism for withholding prepared actions, or whether it is an inherent part of movement preparation. To address this question, we used transcranial magnetic stimulation (TMS) to estimate CSE changes preceding 1) RT movements; 2) movements synchronized with a predictable signal (predictive timing or PT movements); and 3) self-paced movements. Results show that CSE decreases with a similar temporal profile in all three cases, suggesting that it reflects a previously unrecognised state in the transition between rest and movement. Although TMS revealed reduced CSE in all movements, the TMS pulse itself had different effects on movement times. TMS given ~200 ms before the times to move speeded the onset of RT and self-paced movements, suggesting that their initiation depends on a form of trigger that can be conditioned by external events. On the contrary, PT movements did not show this effect, suggesting the use of a different triggering strategy prioritizing internal events.