Midfrontal Theta Activity Is Sensitive to Approach- Avoidance Conflict

Midfrontal theta (FM0) in the human EEG is commonly viewed as a generic and homogeneous mechanism of cognitive control in general and conflict processing in particular. However, the role of FM0 in approach-avoidance conflicts and its crosstask relationship to simpler stimulus-response conflicts remain to be examined more closely. Therefore, we recorded EEG data while 59 healthy participants (49 female, 10 male) completed both an approach-avoidance task and a flanker task. Participants showed significant increases in FM0 power in response to conflicts in both tasks. To our knowledge, this is the first study to show a direct relationship between FM0 and approach-avoidance conflicts. Crucially, FM0 activity was task dependent and showed no cross-task correlation. To assess the possibility of multiple FM0 sources, we applied source separation [generalized eigendecomposition (GED)] to distinguish independent FM0 generators. The activity of the components showed a similar pattern and was again task specific. However, our results did not yield a clear differentiation between taskspecific FM0 sources for each of the participants. Overall, our results show FM0 increases in approach-avoidance conflicts, as has been established only for more simple response conflict paradigms so far. The independence of task-specific FM0 increases suggests differential sensitivity of FM0 to different forms of behavioral conflict.