Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Hospital Clínic, Barcelona, Spain.
Department of Radiology, Rehabilitation and Physiotherapy, School of Medicine, National School of Occupational Medicine, Carlos III Institute of Health, Madrid, Spain.
Psychophysiology. 2021 Mar;58(3):e13752. doi: 10.1111/psyp.13752. Epub 2020 Dec 21.
A startling auditory stimulus (SAS) induces a reflex response involving, among other reactions, a strong contraction of the orbicularis oculi muscle (OOc) and subsequent eye closure. A SAS also induces the StartReact effect, a significant shortening of reaction time in subjects ready for task execution. We examined the obvious conflict appearing when a StartReact paradigm requires participants with eyes closed to open their eyes to look for a visual target. We recorded OOc EMG activity and eyelid movements in healthy volunteers who were instructed to open their eyes at perception of a somatosensory imperative stimulus (IS) and locate the position of a Libet's clock's hand shown on a computer screen at 80 cm distance. In 6 out of 20 trials, we delivered a SAS simultaneously with the IS. The main outcome measures were reaction time at onset of eyelid movement and the time gap (TG) separating subjective assessment of the clock's hand position from real IS issuing. Control experiments included reaction time to eye closing and target location with eyes open to the same IS. Reaction time was significantly faster in SAS than in noSAS trials and slower for eye opening than for eye closing in both conditions. In the eye-opening task, TG was significantly shorter in SAS with respect to noSAS trials, despite the presence of the SAS-related burst in the OOc before EMG cessation. Our results indicate that the StartReact effect speeds up eye opening and location of a target in the visual field despite the startle reaction opposing the task.
惊声刺激（SAS）会引起反射反应，包括眼轮匝肌（OOc）强烈收缩和随后的闭眼。SAS 还会引起 StartReact 效应，即在准备执行任务的受试者中，反应时间显著缩短。我们研究了当 StartReact 范式要求闭眼的参与者睁开眼睛寻找视觉目标时出现的明显冲突。我们记录了健康志愿者的 OOc EMG 活动和眼睑运动，他们被指示在感知到躯体感觉强制性刺激（IS）时睁开眼睛，并在 80 厘米距离的计算机屏幕上定位 Libet 时钟的指针位置。在 20 次试验中的 6 次中，我们同时发出 SAS 和 IS。主要观察指标为眼睑运动开始时的反应时间和从主观评估时钟指针位置到实际 IS 发出的时间间隔（TG）。对照实验包括在相同 IS 下睁开眼睛时的闭眼反应时间和目标位置。SAS 试验中的反应时间明显快于无 SAS 试验，在两种情况下，睁眼的反应时间都比闭眼慢。在睁眼任务中，尽管在 EMG 停止之前 OOc 中存在与 SAS 相关的爆发，但 SAS 时的 TG 明显短于无 SAS 试验。我们的结果表明，尽管惊跳反应与任务相反，但 StartReact 效应仍能加快睁眼和在视野中定位目标的速度。
