Motivational mechanisms (BAS) and prefrontal cortical activation contribute to recognition memory for emotional words. rTMS effect on performance and EEG (alpha band) measures

The present research addressed the question of where memories for emotional words could be represented in the brain. A second main question was related to the effect of personality traits, in terms of the Behavior Activation System (BAS), in emotional word recognition. We tested the role of the left DLPFC (LDLPFC) by performing a memory task in which old (previously encoded targets) and new (previously not encoded distractors) positive or negative emotional words had to be recognized. High-BAS and low-BAS subjects were compared when a repetitive TMS (rTMS) was applied on the LDLPFC. We found significant differences between high-BAS vs. low-BAS subjects, with better performance for high-BAS in response to positive words. In parallel, an increased left cortical activity (alpha desynchronization) was observed for high-BAS in the case of positive words. Thus, we can conclude that the left approach-related hemisphere, underlying BAS, may support faster recognition of positive words.