Sollers J J, Hackley S A
University of Missouri-Columbia 65211, USA.
Psychophysiology. 1997 Sep;34(5):518-26. doi: 10.1111/j.1469-8986.1997.tb01738.x.
The question of whether a common mechanism underlies the facilitation of voluntary and reflexive reactions by a warning stimulus was investigated in two experiments. In both studies, the foreperiod preceding an intense noise burst was manipulated within and between blocks of trials. Previous reaction time experiments have shown that individuals respond fastest at the shortest foreperiod for between-block manipulations and fastest at the longest foreperiod when foreperiod duration is varied unpredictably from trial to trial. In the present research, this pattern was found for voluntary hand-grip responses, but acoustic startle blinks were facilitated at long foreperiods for both within- and between-block manipulations. Invariance of the trisynaptic postauricular reflex across foreperiod conditions was evidence against any general activation of low-level motor pathways by warning stimuli. Analyses of nonreflexive lid movements subsequent to startle blink suggested that inhibition of spontaneous blinking during the foreperiod may have contributed to the unexpected divergence between voluntary reactions and eyeblink reflexes.
在两项实验中，研究了警告刺激促进随意反应和反射反应是否存在共同机制这一问题。在这两项研究中，在试验块内和试验块之间操纵了强烈噪声爆发之前的前周期。先前的反应时间实验表明，对于块间操纵，个体在前周期最短时反应最快；而当前周期持续时间在每次试验中不可预测地变化时，个体在前周期最长时反应最快。在本研究中，随意握力反应呈现出这种模式，但对于块内和块间操纵，在前周期较长时听觉惊跳眨眼均得到促进。三突触耳后反射在前周期条件下的不变性证明了警告刺激不会对低水平运动通路产生任何一般性激活。对惊跳眨眼后非反射性眼睑运动的分析表明，在前周期期间自发眨眼的抑制可能导致了随意反应和眨眼反射之间出乎意料的差异。
