The alternated brain states in resting state after immoral decisions

Immoral decisions, which engage both cognitive control and reward system, bring both cognitive and neural consequences. However, how dishonesty has an impact on the brain’s dynamic alterations is still unclear. In this work, we attempt to understand the impact of immoral decisions on the brain states’ dynamics using both resting-state and task-state fMRI data collected before, during, and after an information-passing task involving dishonest choices with rewards. We employed the Hidden Markov Model (HMM) to capture the changes in the brain dynamics state, in which the changes that happen between pre- and post-task are hypothesized to be linked to behavior and brain dynamics during the task. First, we identified 4 intrinsic brain states across both resting scans and task scans, including one reward state (state 1) and one control network (state 3). The fractional occupancy (FO) of the control network decreased after the task, and subsequent analysis showed that it was linked to brain dynamics during the task: as dishonesty persisted, FO of the control network decreased while FO of the reward network increased. Moreover, the post-task control network was negatively correlated with motivated dishonesty, suggesting that stronger control network recruitment counteracts immoral tendencies. In contrast, early in the task, the reward network positively correlated with motivated dishonesty, indicating that the representation and sensitivity to reward attribution were tied to dishonest choices. A complementary analysis using drift diffusion modeling confirmed that the reward network tracked the weightings placed on monetary rewards, and the level of activation of the reward network before the task is associated with a bias in dishonesty. Together, these findings suggest that the ‘post-moral decision brain’ operates not as a static system but as a set of dynamically shifting states, whose adaptive trajectories may underlie the lasting effect of moral erosion during sustained dishonest behavior.