Incidental self-processing modulates the interaction of emotional valence and arousal.

The middle insula has been associated with incidental self-processing of negative information elicited by individual's handwriting. However, emotional valence and arousal have been proved to work in an interactive way and located in middle insula. The present functional magnetic resonance imaging study used participant's handwritings as material to explore how incidental self-processing affected the interaction of valence and arousal and its neural basis. Each participant was asked to read silently emotional and neutral words written by himself/herself or the other person. The right middle insula as well as the left putamen showed greater activations in response to emotional stimuli evoking conflicting approach-withdrawal tendencies (i.e., positive high-arousal and negative low-arousal words) relative to stimuli evoking congruent approach versus withdrawal tendencies (i.e., positive low-arousal and negative high-arousal words), whereas a reverse activation pattern in these two regions was observed during processing other-handwriting. The current study indicated that incidental self-processing modulates the interaction of emotional valence and arousal.