Emotional contexts modulate intentional memory suppression of neutral faces: Insights from ERPs

The main goal of present work is to gain new insight into the temporal dynamics underlying the voluntary memory control for neutral faces associated with neutral, positive and negative contexts. A directed forgetting (DF) procedure was used during the recording of EEG to answer the question whether is it possible to forget a face that has been encoded within a particular emotional context. A face-scene phase in which a neutral face was showed in a neutral or emotional scene (positive, negative) was followed by the voluntary memory cue (cue phase) indicating whether the face had to-be remember or to-be-forgotten (TBR and TBF). Memory for faces was then assessed with an old/new recognition task. Behaviorally, we found that it is harder to suppress faces-in-positive-scenes compared to faces-in-negative and neutral-scenes. The temporal information obtained by the ERPs showed: 1) during the face-scene phase, the Late Positive Potential (LPP), which indexes motivated emotional attention, was larger for faces-in-negative-scenes compared to faces-in-neutral-scenes. 2) Remarkably, during the cue phase, ERPs were significantly modulated by the emotional contexts. Faces-in-neutral scenes showed an ERP pattern that has been typically associated to DF effect whereas faces-in-positive-scenes elicited the reverse ERP pattern. Faces-in-negative scenes did not show differences in the DF-related neural activities but larger N1 amplitude for TBF vs. TBR faces may index early attentional deployment. These results support the hypothesis that the pleasantness or unpleasantness of the contexts (through attentional broadening and narrowing mechanisms, respectively) may modulate the effectiveness of intentional memory suppression for neutral information.