Monotonous and repetitive tasks cause vigilance, or sustained attention decrement, which possibly leads to irreparable accident consequences in the aerospace and nuclear industry. Buffering the decrement of vigilance in visual search tasks is essential for cognitive enhancement and ergonomic research. This study aimed to evaluate the efficacy of anodal transcranial direct current stimulation (tDCS) applied to the left frontal eye field (FEF) to improve the performance of the sustained visual search. Twenty-seven healthy participants received anodal and sham tDCS of 2 mA for 28.8 min and completed a visual search task lasting for approximately 40 min without any break. For the online effect, results showed that the d′ hit rate and accuracy under anodal tDCS were significantly higher than those under sham conditions during 0–19.2 min time intervals. For the after-effect, compared with sham, anodal tDCS caused significantly higher d′ in the 10 min after completing the tDCS. Our findings suggest that anodal tDCS over the left FEF could effectively mitigate the decline of visual vigilance performance by buffering cognitive resource depletion.

This study used the event-related potential technique to explore the neural correlates of outcome evaluation about helping others during a decision task. The results showed that the amplitude of feedback-related negativity elicited by ‘failed outcome’ (indicating a failure in helping others) was larger than that elicited by ‘successful outcome’ (indicating a success in helping others). Failed outcome also elicited a larger and longer P300 than successful outcome. The feedback-related negativity and P300 reflect the automatic process in an early stage and the control process in a late stage of outcome evaluation, respectively. Accordingly, these event-related potential results have shown the time course of outcome evaluation about helping others, and suggest that brain response to outcome information of helping others is generally similar to those in economic decision tasks.