关键词: 内侧额叶负波, 性别差异, 结果评价, 赌博任务

Abstract: Fast outcome evaluation allows for rapid decision-making and adjustment for future behavior. Recent studies utilizing event-related potentials (ERPs) technique to investigate the evaluative processes in the brain, have found a negative deflection mainly at the media-frontal regions of the brain, called as feedback related negativity (also called, media-frontal negativity, MFN). First, MFN was found in the self-performance task, reflecting that the outcomes were first evaluated as worse than what was anticipated. Subsequent studies found the MFN effects were also obtained in the other-performance gambling tasks while perceiving the outcome, reflecting subjective judgments about whether an event has positive or negative value for the monitored individuals. Our previous study found the MFN was larger in their self-performance task than the other-performance gambling task, but the outcomes of both tasks were their self-related outcomes, with females response differing from males. Previous studies didn’t separate these confusing factors and it is not clear whether the MFN amplitude is sensitive to their self-performance outcome or their self-related outcome. So we want to investigate the mechanism of perceiving self-related outcome and other-related outcome separately in both gambling tasks. If the MFN of self-related and other-related outcome shows no difference in the self-performance tasks, besides, the amplitude of MFN in the self-performance gambling task is larger than in the other-performance gambling tasks, these suggest that the MFN is sensitive to the self-response outcome. Nevertheless, we should consider the gender difference.
Thirty-two participants (16 males and 16 females) completed the self-performance gambling task and observed the other-performance gambling task, and both gambling tasks included self-related outcome and other-related outcome. The electroencephalogram was recorded from 64 scalp electrodes. All of the data were segmented into 700ms epochs, including a 100ms pre-stimulus baseline period, based on time markers for the onset of the feedback stimuli. The MFN was statistically evaluated using SPSS 16.0 with multiple df repeated measures comparisons.
We found that the MFN amplitude was larger in self-performance task than the other-performance task, and the self-related and other-related outcome didn’t show any difference, indicating that the MFN is sensitive to their self-response outcome. Subjects has strong motivation about their self-related outcome, but while perceiving the other-related outcome, in the one hand, they didn’t want to another people to win; in the other hand, they also didn’t want to another people to lose. In the self-performance task, when males perceived their self-related outcomes, the MFN was larger than perceiving other-related outcomes. On the contrary, in the other- performance task, the females elicited larger MFN while perceiving other-related outcomes than self-related outcomes. In both tasks, females elicited larger MFN while perceiving other-related outcomes than males. The results indicate that the MFN is sensitive to social information about affective motivation impacts.
All of these results suggest that the evaluation criteria are different between monitoring their self-performance outcomes and other-performance outcomes of social information. Male and female responses vary in different directions of valence and have various significance of affective motivation in terms of whether gains or losses are negative for themselves. Gender differences in complex social behavior, results from the different mechanism of rapid outcome evaluation processing based on individual subjective criteria.

Key words: medial-frontal negativity, gender difference, outcome evaluation, gambling task