The Effect Of Depression Tendency On Outcome Evaluation And Related Brain Mechanism

Before the decision outcome,decision makers will generate expected outcome,then to evaluate the actual result is good or bad depend on the anticipation.Counterfactual thinking is the thought process which comparing the realistic outcome with the possible outcome.To compare realistic outcome with better or wore expected results will affect the outcome evaluation.Based on the Beck depressive schema theory,high depressive people tend to do negative evaluation.This study thinks that it is because high depressive people have a better expected results,tend to compare practical results with better expected results,then generate upward counterfactual thinking,and do negative evaluation of reality as a result.Therefore,to explore the effect of levels of depression on counterfactual thinking,could help to explain the negative evaluation of high depression and the tendency of emotional disorders.Objective With the help of event-related potential(ERP),the present study explore the pattern of ERPs associated with outcome evaluation,such as feedback-related negativity(FRN)and the P3,between low and high level depression groups.Specifically,explore the effect of depression level on outcome expectation and counterfactual thinking.Materials and Methods The present study adopted the Self-Rating Depression Scale(SDS)to screening high depression group of 20 and low depression group of 20.All subjects completed a adapted “Monetary Incentive Delay Task(MID)”,and used ERP technology to record ERP components(mainly FRN and P300)induced by cues and feedback outcomes in different context.Results Experimental 1: There was no significant difference between reward and punish cues neither on FRN nor P300.As for feedback outcome,negative outcomes reduce greater FRN and smaller P300 amplitude compared with positive outcomes.Experimental 2: As for condition cues,there is no significant difference between reward and punish condition cues on FRN amplitude in low depression group;but high depression group reduce greater FRN amplitude in punish condition cue than reward condition cue.High depression group induce greater FRN amplitude on punish condition cue compared with low depression group.As for FRN induced by outcome feedback,there is significant difference between low and high depression group in negative feedback outcome rather than positive feedback outcome: low depression group have no difference among far-closeness,medium-closeness and near-closeness outcomes,nevertheless,there is significant difference of FRN amplitude among the 3 types of outcome closeness in high depression group,that is the FRN induced by far-closeness and medium-closeness were greater than near-closeness outcome.Conclusion FRN amplitude induced by condition cues indicate that high depression group is more sensitive to punish cues.Correspondingly,only in the punish condition(negative feedback)the present study observed the difference between low and high depression group.The results show that high depression group is more sensitive to near-closeness outcome in negative feedback(near misses,upward counterfactual thinking)compared with low depression group,this result indicate that depression level amplify upward counterfactual thinking.