The two-sample t-test computed on the loading parameters for the correlated EEG-coherence component showed a group difference with corrected p = 0.0016 (t39 = 4.10), with LTAA having lower loading than NSAC (thus the negative correlation coefficient with the NAcc seed-correlation component, where LTAA had higher loading than NSAC). We also compared the loading parameters for the EEG coherence component using a linear model, covarying for smoking and education. This analysis showed a group difference with p = 0.01 (t37 = 2.73), so smoking and education could not explain all of the group difference. Fig. 2, Fig. 3 illustrate the EEG-coherence component in a series of maps. For higher resolution viewing, MATLAB .fig files are included as supplemental data. As each element of the component corresponds to the contribution to coherence between a pair of electrodes within one of the frequency bands (theta, alpha1, alpha2, beta1, beta2, gamma1, gamma2), the magnitude of its contribution can be visualized within a matrix where its position denotes the electrode pair (i.e., the row and column labels correspond to the electrode pair), with separate
