Valence-based age differences in medial prefrontal activity during impression formation.

Reports of age-related changes to medial prefrontal cortex (mPFC) activity during socio-cognitive tasks have shown both age-equivalence and under recruitment. Emotion work illustrates selective mPFC response dependent on valence, such that negative emotional images evoke increased ventral mPFC activity for younger adults, while older adults recruit vmPFC more for positive material. By testing whether this differential age-related response toward valenced material is also present for the social task of forming impressions, we may begin to understand inconsistencies regarding when age differences are present vs. absent in the literature. Using fMRI, participants intentionally formed impressions of positive and negative face-behavior pairs in anticipation of a memory task. Extending previous findings to a social task, valence-based reversals were present in dorsal and ventral mPFC, and posterior cingulate cortex. Younger adults elicited increased activity when forming negative impressions, while older adults had more recruitment when forming positive impressions. This suggests an age-related shift toward emphasizing positive social information may be reflected in the recruitment of regions supporting forming impressions. Overall, the results indicate an age-related shift in neural response to socio-cognitive stimuli that is valence dependent rather than a general age-related reduction in activity, in part informing prior inconsistencies within the literature.