Effects of probability bias in response readiness and response inhibition on reaching movements
Effects of probability bias in response readiness and response inhibition on reaching movements
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DOI：
10.1007/s00221-014-3846-8
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发表时间：
2014-04-01
影响因子：
2
通讯作者：
Mirabella, Giovanni
中科院分区：
文献类型：
--
作者：
Federico, Paolo;Mirabella, Giovanni
众所周知，不同的刺激频率会导致对更可能的刺激做出更快的反应。然而，这种概率偏差对反应抑制的影响仍然存在争议。为了解决这个问题，我们对 18 名惯用右手的健康受试者进行了两个版本的停止信号任务。在一种版本中，当受试者被要求用右臂产生快速反应（无停止试验）时，我们操纵了左右目标出现的频率，而在右或左目标之后以相同的频率出现停止信号（无停止信号偏差）。在另一个版本中，我们操纵了右侧或左侧目标之后停止信号出现的频率，而针对右侧或左侧目标的不停顿试验具有相同的频率（停止信号偏差）。令人惊讶的是，我们发现对更频繁的刺激的反应准备程度即使有的话也非常有限。然而，不间断的信号偏差对抑制控制的速度有影响，因为受试者总是更快地抑制向目标不太可能出现的一侧的移动。不同的是，停止信号偏差的影响要大得多。事实上，受试者更快地停止向目标更频繁的一侧移动，而他们在接触更可能的目标时表现出更长的反应时间。总的来说，这些结果表明行动准备和行动抑制是独立的竞争过程，但受试者倾向于自动更加重视停止任务。
It is solidly established that unequal stimulus frequencies lead to faster responses to the more likely stimulus; however, the effect of this probability bias on response inhibition is still debated. To tackle this issue, we administered two versions of the stop-signal task to 18 right-handed healthy subjects. In one version, we manipulated the frequency of right and left targets appearance when subjects were required to produce speeded responses (no-stop trials) with the right arm, whereas stop signals occurred with equal frequencies after right or left targets (no-stop signal bias). In the other version, we manipulated the frequency of appearance of stop signals after right or left targets, whereas no-stop trials toward right or left targets had the same frequency (stop-signal bias). Surprisingly, we found a very modest, if any, increase in response readiness toward the more frequent stimulus. However, the no-stop signal bias had an effect on the speed of inhibitory control, as subjects were always faster to suppress a movement toward the side where targets were less likely to occur. Differently, the stop-signal bias had a much more powerful effect. In fact, subjects were faster to withhold movements toward the side where targets were more frequent, while they exhibited longer reaction times for reaches toward the more likely targets. Overall, these results suggest that action preparation and action inhibition are independent competing processes, but subjects tend to place automatically greater importance on the stop task.