ERP Research On Emotional Effect In Source Memory - Adjustment Of Trait Anxiety And Presentation Time

We use two experiments to explored both attention and memory bias for negative stimulus, applying the technique of Event-related potential and the source memory multiple-task paradigmContradictory findings make it difficult to draw satisfactory conclusions about whether a memory bias in high-trait-anxiety individuals is more likely to influence implicit memory (familiarity) or explicit memory (recollection). The present study explored both cognitive and brain mechanisms of source retrieval in different emotional valence contexts in16high-trait-anxiety college students (mean trait anxiety score59.06±3.88) using ERP measurement and source memory multiple-task paradigm. It was found that, during retrieval, ERPs of studied items were more positive than new items between300and500ms after stimulus onset (old/new effect) in all contexts, regardless of whether source retrieval was successful or unsuccessful. For successful source retrieval between500and700ms, there was old/new effect in all contexts. However, for unsuccessful source retrieval, there was no significant old/new effect in happy and neutral contexts, though significant old/new effect was observed in the fearful context. Between700and1200ms, there was significant old/new effect for successful source retrieval in happy and neutral contexts. However, in the fearful context, the old/new effect was reversed, ERPs were more negative for successful source retrieval compared to correct rejections. Moreover, there was significant emotion effect for successful source retrieval at this time window. Further analysis showed ERPs of old items were more negative in fearful context than in neutral context. The results suggest that the early implicit source retrieval of fearful stimulus (source familiarity) were enhanced, but the explicit source retrieval of fearful stimulus (source recollection) were weakened in high-trait-anxiety individuals.In experiment2, we explore negative bias in encoding phase and the recollection phase of source memory in higher or lower level of anxiety people, and the effect of the emotional context and presentation time. Through high and low anxiety subjects (mean trait anxiety score54.56±3.78;33.24±4.32) were each15of30subjects, we explore the behavior and brain mechanisms in different valence background. In encoding phase, the results showed that DM effect in the successful source retrieval conditions under the context of fear last longer than under neutral background, and between300and1600ms, the ERPs of successful source retrieval conditions under the context of fear were more positive than under the neutral context. Between300and700ms after stimulus onset or in the successful source retrieval conditions, the ERPs of short presentation time conditions were more positive than long presentation time. In retrieval phase, the results showed that old/new effect in the successful source retrieval conditions under the context of fear last longer than under neutral background, and between300and700ms, the ERPs of successful source retrieval conditions under the context of fear were more positive than under the neutral context. In the test phase of the300-1600ms, we find the significant interaction effects between presentation time and trait anxiety in the successful source retrieval conditions, further contrast showed ERPs were more positive for short presentation time compared to long presentation time in parietal area and central-parietal area. In general, we successful find the old/new effect in retrieval phase and the DM effect in encoding phase in experiment2, and find the emotion effect, the effect of presentation time and the interaction between presentation time and trait anxiety.Experiment1, the ERPs of successful source retrieval conditions under the context of fear were more negative than under the neutral context in high anxiety individuals, while the ERPs of successful source retrieval conditions under the context of fear were more positive than under the neutral context in all subjects. These results demonstrated the experimental results were affected by the level of trait anxiety, difficulty of the task and the experimental set-up the combined effect.