The default mode network is one of the first hits I got when looking for mPFC and PFC activation, after seeing they were highly correlated (here).
The Relationship Between Social Support and Processes: A Review With Emphasis on Underlying Mechanisms and Implications for Health (1996)
Some positive effects of social support on cardiovascular, endocrine, and immune systems.
Loneliness, Social Network Size, and Immune Response to Influenza Vaccination in College Freshmen (2005)
Perceived Stigmatization, Ingroup Pride, and Immune and Endocrine Activity: Evidence From a Community Sample of Black and Latina Women (2013)
From Neural Responses to Population Behavior: Neural Focus Group Predicts Population-Level Media Effects (2012)
(they love the word orthogonal, presumably meaning unrelated) -- in a study orthogonal to the present one.
Correlating call volume to 1-800-QUIT-NOW to neural activation in their ROI depending on ads presented
Overall neural activity across all ads "predicted" (correlated with) smoking reduction after watching, beyond self-reports
31 participants, heavy smokers who really wanted to quit
Mean neural activity in MPFC ROI rated C > B > A, while experts and participants put C last.
C > B > A was also more frequent individually than by chance (33%)
B > A > C was most frequent in self-reports
The neural ordering was confirmed by the % increase in call volume