Perceived social support moderates neural reactivity to emotionally valenced stimuli during pregnancy.

Reactivity to emotional information, measurable at the level of neural activity using event-related potentials, is linked to symptoms of affective disorders. Behavioral evidence suggests that contextual factors, such as social support, can alter emotional reactivity such that affective responding is normalized when social support is high. This possibility remains largely untested at the neural level, specifically through approaches that can offer insight into the mechanistic processes contributing to individual differences in emotional reactivity. Yet, such knowledge could be useful for prevention and intervention efforts, particularly with groups at risk for increased emotional reactivity, such as pregnant mothers for whom emotional distress predicts both maternal and child outcomes. Expectant mothers took part in a longitudinal study that tested whether the late positive potential (LPP), a neural index of reactivity to emotional information, was moderated by maternal perceptions of social support. In the third trimester of pregnancy, lower perceived social support was associated with an absence of a traditional LPP effect, which differentiates valenced from neutral stimuli. Findings suggest that perceptions of social support may normalize emotional processing at the neural level and highlight the potential importance of social support modulation of emotional reactivity during times of known biological change.