Exploratory Granger causal connectivity analysis. Note that due to the coarse spatial resolution of the source reconstruction technique, the selected ROIs are not precise anatomical regions but rather represent broad divisions of cortex. A, Granger causal connectivity methodology. The linear response to healthiness (least to most healthy) was used as a surrogate for self-control. Left, Source reconstruction of the healthiness signal produced an intensity map for the modeled dipolar patches within each subject (shades of blue). Pink, dlPFC ROI from self-control success > failure. Middle, Time courses of the MIP for each dipole in each ROI were extracted and averaged, then selected for specified time windows (gray box). Right, For each ROI, data for each time window were concatenated across subjects and preprocessed (linear detrending, subtraction of temporal mean, subtraction of ensemble mean, first-order differencing) before being entered into Granger causal modeling. B, Model and causal connectivity for health contrast 450–650 ms after stimulus onset. All displayed connections are significant at a threshold of p = 0.01, Bonferroni-corrected.