Grillon Christian, Hill Jeffrey
DHHS, NIH, NIMH Mood and Anxiety Disorder Program, National Institute of Mental Health, 15K North Drive, Bldg 15K, MSC 2670, Bethesda, MD 20892-2670, USA.
Brain Res Cogn Brain Res. 2003 Jul;17(2):400-5. doi: 10.1016/s0926-6410(03)00141-1.
Arousal can modulate information processing, including associative learning. However, there are conflicting results as to whether arousal affects eyeblink conditioning in humans. One potential problem with previous studies is that they have not taken into account factors that are known to affect conditioning. One such factor is the strength of the unconditioned response (UR). Despite evidence that greater UR leads to greater conditioned responses (CR), prior studies have not examined the role of the UR in CR performance. Prior studies have also usually classified subjects into low and high arousal groups based on a priori categorization without reliance on objective measures of arousal. The present study was designed to examine the impact of arousal on delay eyeblink conditioning. Changes in arousal levels were obtained by having participants view pictures selected for their a priori emotional and arousal values as being pleasant/arousing, unpleasant/arousing, or neutral/not arousing. Each subject viewed pictures of only one category. The spontaneous fluctuation of the skin conductance was taken as an index of physiological arousal. Subjects were divided into low and high arousal groups according to a median-split. Results showed that the rate of CR was positively related to the amplitude of the UR, but was not affected by emotional pictures or by physiological arousal. It is argued that changes in CR during arousal could be due to differences in unconditioned eyeblink strength rather than to changes in associative processes.
觉醒能够调节信息处理过程，包括联想学习。然而，关于觉醒是否会影响人类的眨眼条件反射，研究结果存在冲突。以往研究的一个潜在问题是，它们没有考虑到已知会影响条件反射的因素。其中一个因素就是无条件反应（UR）的强度。尽管有证据表明更强的UR会导致更强的条件反应（CR），但先前的研究并未考察UR在CR表现中的作用。先前的研究通常还会根据先验分类将受试者分为低觉醒组和高觉醒组，而不依赖于客观的觉醒测量指标。本研究旨在考察觉醒对延迟眨眼条件反射的影响。通过让参与者观看根据其先验情绪和觉醒值被选为愉悦/唤起、不愉快/唤起或中性/无唤起的图片，来实现觉醒水平的变化。每个受试者只观看一类图片。皮肤电导率的自发波动被用作生理觉醒的指标。根据中位数分割将受试者分为低觉醒组和高觉醒组。结果表明，CR的速率与UR的幅度呈正相关，但不受情绪图片或生理觉醒的影响。有人认为，觉醒过程中CR的变化可能是由于无条件眨眼强度的差异，而不是联想过程的变化。
