Effects of negative emotion and its correlated neural activity on secretory immunoglobulin A

In this study, we investigated how the negative emotional arousal induced by watching a number of unpleasant images altered the concentration of secretory immunoglobulin A (SIgA) in saliva. Although our results found discrepancies among participants’ SIgA concentration (i.e. some participants’ SIgA decreased after watching unpleasant pictures, whereas others increased), further analysis revealed correlations among participants’ changes in SIgA concentration, their general coping styles and their actual strategies for emotion regulation when perceiving unpleasant pictures, and the event-related potentials (ERPs) associated with viewing unpleasant pictures. The participants whose SIgA increased after watching unpleasant pictures (the "Increasers") had higher positive coping scores in the Trait Coping Styles Questionnaire (TCSQ) than those whose SIgA decreased (the "Decreasers"). Also, rela-tive to the "Decreasers",the "Increasers" tended to use more emotion regulation strategies, particu-larly with extremely negative pictures. The amplitude of their late positive potentials (LPPs) exhibited a reverse dissociation pattern for extremely negative pictures versus least negative ones and was related to the cognitive evaluation of the stimuli’s meaning. In sum, this research revealed the psychological mechanisms by which negative emotional states influence the immune system and the related ERP changes.