关键词: 反馈加工, 行为调节, FRN, P300

Abstract: It is important for successful future behavior to learn from past mistakes. In the last two decades, performance monitoring has received a lot of attention. Some studies showed that the FRN (feedback related negativity) was sensitive to adjustment behavior following the feedback stimulus, whereas some studies did not find any relationship between ERN amplitude and behavioral adjustments. So it is unclear how the brains learn from past mistakes. In the present study, we used a time-estimation task with feedback type (correct, incorrect-slow, incorrect-fast with the graded incorrect feedback as a function of the degree of error under gain and loss condition. Event-related potentials were recorded to explore the neural mechanism of the performance monitoring and behavioral adjustment in time-estimation task. Thirteen healthy volunteers participated in this study. Subjects were asked to estimate a 1-second interval and feedback was based on the estimation of the participants. Subjects received graded incorrect feedback as a function of the degree of error and the ‘punishment’ on incorrect trials was loss 30 Yuan, loss 20 Yuan, or loss 10 Yuan relative to correct trials. Analyses of the behavioral data revealed that the subjects shortened or lengthened their judgments according to feedback and the amount of adjustment was related to the suggested degree of error. Behavioral data indicated that the subjects made use of the information provided by the feedback in adjusting their behavior from one trial to the next. Analyses of ERP data focused on feedback-related negativity (FRN) and P300. FRN analyses revealed that FRN was sensitive to feedback value but insensitive to fast-slow incorrect feedback or three punishment levels. These results suggested the dissociation between the processes underlying generation of the FRN and the processes responsible for behavioral adjustments. P300 showed an opposite pattern relative to FRN: P300 was modulated not only by fast-slow incorrect feedback but also by the three incorrect levels. Post hoc tests confirmed that P300 became larger in the order of Loss 10 Yuan < Loss30Yuan whether in the gain or the lose condition as verified by the behavioral results. In this case, the additional information provided in the time estimation task would be used by systems that produced the P300 to update reward expectations and to guide adaptive decision making. Thus, P300 is taken as an index of the updating of action representation and a brain potential of behavioral adjustment. These findings suggest that brain responses in performance monitoring and behavioral adjustment may be divided into an earlier rapid, semi-automatic, alerting process which indicates that behavioral adjustments are needed and a later slower, conscious cognitive appraisal process which indicates updating of action representation that vary as a function of current contexts and processing goals.

Key words: Feedback processing, Behavior adjustment, FRN, P300