CAJ | 학술논문

急性应激如何影响工作记忆还不清楚。采用电影片断诱发被试的急性应激或中性状态后，让其完成数字N—back任务并同时记录脑电。结果发现，低负荷工作记忆诱发的P3显著大于高负荷工作记忆；在0-back任务中，急性应激组诱发的P3显著大于控制组；而在2-back任务中，这种差异不显著。这些结果表明急性应激对工作记忆的影响受工作记忆负荷调节，支持了双竞争理论模型。
급성응격여하영향공작기억환불청초。채용전영편단유발피시적급성응격혹중성상태후，양기완성수자N—back임무병동시기록뇌전。결과발현，저부하공작기억유발적P3현저대우고부하공작기억；재0-back임무중，급성응격조유발적P3현저대우공제조；이재2-back임무중，저충차이불현저。저사결과표명급성응격대공작기억적영향수공작기억부하조절，지지료쌍경쟁이론모형。
Previous studies have shown that the effect of acute stress on working memory （WM） is mixed. Both the impairment and improvement effect of acute stress on working memory have been found. In neuroimaging studies, some studies showed that the activity of fronto-parietal cortex relevant to WM was reduced when acute stress presented, whereas some other studies showed that the activity increased. A recent study showed that this paradoxical effect might be related to the WM load. To this end, we conducted an EEG study by implementing a working memory paradigm to examine how the acute stress affects ongoing working memory processing. In this paradigm, acute stress/neutral movie clips were used to induce stress status. Participants performed an N-back task with sequentially presented number, in which they were asked to identify whether the current number was identical to the one presented two trials before （i.e., 2-back, higher WM load） or with 1 （0-back, lower WM load）. The heart beats and subjective feeling were recorded for stress measurement. The heart beats and negative emotional feeling were significantly higher in the stress group than the neutral group, suggesting a successfully acute stress induction. The amplitude of parietal P3 was significantly larger in the 0-back condition than in the 2-back condition. These results were consistent with the previous EEG studies using the N-back task, which showed the smaller P3 in high WM load condition. Furthermore, in the 0-back task, the P3 amplitude in stress condition was larger than in the control condition. By contrast, in the 2-back task, no significant difference was found between the stress group and the control group. These results can easily be explained by the recently proposed dual competition model positing that emotional and cognitive processes, when operating simultaneously, would compete with each other for the limited neural resources. Specifically, processing of stress stimuli may interfere with ongoing cognitive processes when cognitive resources are not entirely devoted to goal-directed processing under a lower task demanding condition, such as during the 0-back task in our study. However, when more resources are required to achieve goal-directed behavior such as in the 2-back WM task, the interference effect is attenuated due to the suppression of stress processing. Together, these results provide direct evidence for the dual competition model.