Intrinsic functional connectivity of medial prefrontal cortex predicts the individual moral bias in economic valuation partially through the moral sensitivity trait

An individual's economic valuation of a given object is biased by the moral status of the persons to whom the object is attached. The neural basis for how such "moral bias" occurs, especially how it is maintained in the resting state, are largely unknown. In the current study, we explored this question by correlating the functional connectivity with participants' behavioral performance measured in a novel task which captured how the economic valuation was influenced by given moral information. Seed-based FC analysis showed that the functional connectivity between the mPFC and the orbital mPFC (omPFC), the mPFC and the precuneus, the mPFC and the left anterior cingulum, were significantly associated with the behavioral index of morality effect on economic valuation. Multivariate machine learning-based regression analysis showed that connections in the mPFC network, as well as in the putamen network could well predict the behavior performance, indicating that this mPFC network and the putamen network were crucial for this moral bias. Our results further revealed that the individuals' personal trait of moral sensitivity served as a mediator between the rsFC of mPFC network and the behavioral index of morality effect on economic valuation.