急性应激损害对威胁刺激的注意解除

急性应激会增强个体对威胁刺激的注意偏向, 但急性应激是增强了对威胁刺激的注意定向还是损害了对威胁刺激的注意解除还不清楚。本研究采用社会评估冷压任务和点探测任务, 结合事件相关电位技术, 考察急性应激对威胁刺激注意偏向影响的认知机制。在进行社会评估冷压任务后, 应激组个体的状态焦虑和皮质醇浓度显著升高。在注意偏向中, 应激组对威胁刺激的注意解除比控制组更慢, 应激组和控制组在对威胁刺激的注意定向上无显著差异。ERP结果上, 威胁刺激诱发应激组比控制组产生了更负的SPCN, 在N2pc上没有显著差异。应激组和控制组皮质醇增量的差异和N2pc、SPCN的组间差异均有显著正相关。这些结果说明, 急性应激增强对威胁刺激的注意偏向是因为其损害个体对威胁刺激的注意解除, 这可能是因为急性应激损害了与注意解除相关的额-顶网络的功能所致。

Acute psychological stress impairs attention disengagement toward threat-related stimuli

Threat stimuli catch our attention when compared with neutral stimuli called attention bias, which includes facilitating attention engagement and difficult attention disengagement to threat. Acute stress influences our attention to threat. However, we do not know whether acute stress can enhance facilitating attention engagement or impair attention disengagement toward threat. Therefore, the present study investigated whether attention engagement to threat is enhanced or attention disengagement to threat is weakened when people are stressed. Thirty-six healthy male adults were randomly assigned to a stress group (n = 18) and a control group (n = 18). The stress group underwent socially evaluated cold pressor test (SECPT), whereas the control group underwent a warm water control protocol. The dot-probe task was used to measure the attention bias toward threat. Event-related potentials (ERPs) were used in conjunction with reaction time measures to investigate the time course of attention to threat in the dot-probe task. The N2-posteior-contralateral (N2pc) component measured the initial shift of visual attention to the threatening stimulus, whereas the sustained posterior contralateral negativity (SPCN) component measured the maintenance of visual attention to the threatening stimulus. Reaction time, accuracy rate, and the electroencephalography data of the participants were recorded during the dot-probe task. The state anxiety questionnaire and saliva were acquired at five time points, such as 85 and 70 minutes before the SECPT, immediately before and after the dot-probe task, and 70 minutes after the SECPT. The SECPT successfully induced stress response. Participants in the stress group showed stronger state anxiety and Hypothalamic-Pituitary-Adrenal axis response indicated by increased salivary cortisol concentration after the SECPT than the control group. In addition, no significant differences were found before the SECPT. At the behavioral level, the attention disengagement in the stress group was slower than in the control group. Regarding ERPs, we found a greater amplitude of SPCN (300~600 ms after cue) in the stress group than in the control group. However, no significant effect was found on the amplitude of N2pc between stress group and control group. These results indicate that attention disengagement toward threat is impaired under acute stress situations.