When emotion meets conflict: Additive but not synergistic effects in neural oscillatory activity

Cognitive control allows individuals to regulate their behavior in the face of conflicting or distracting information. Growing evidence suggests that emotional states-particularly self-related emotions-can modulate these control processes. This study explored neural mechanisms underlying amplification of the conflict-adaptation effect (CAE) by self-related emotions, replicating Landman and van Steenbergen (2020). Electroencephalogram (EEG) data were analyzed during two successive trials (Trial N-1 and Trial N) in a prime-probe task. Corrugator muscle activity was also measured as an index of emotional valence. Orthogonal to conflict, word emotion (unpleasant and neutral) and its social context (self- and sender-related) were manipulated. We hypothesized that the emotional facilitation of conflict adaptation by self-related emotional words in Trial N-1 is driven by an affective amplification of conflict-related brain signals. Our behavioral results revealed that emotional words tended to increase CAE, but this effect was threshold-dependent and we failed to replicate the moderation by social context. At the neural level, we replicated earlier results related to conflict and cognitive control; conflict induced early theta synchronization in fronto-central areas and late alpha desynchronization in centro-parietal areas during Trial N-1. Those oscillations showed CAE patterns mirroring the behavioral effect in Trial N. Incongruence increased corrugator activity, indicating that conflict induced unpleasant emotion. Emotion induced neural modulation overlapping with the conflict processing observed in the theta and alpha frequency ranges, suggesting additive but not synergistic effects. Our results reveal neural modulation by conflict and emotional words that might provide input for downstream processes that integrate these signals to drive emotional modulation of behavioral adaptation.