Abstract:

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.

Key words: acute stress, attention engagement, attention disengagement, N2pc, SPCN