To assess the relationship between functional connectivity and patients’ cognitive control performance deficits, we focused on the subnetwork showing a significant cue-by-diagnosis interaction. Because these seven edges specifically showed a cognitive-control-related functional connectivity deficit in schizophrenia patients, we reasoned that they were the most relevant for understanding patients’ cognitive control impairments. For each edge, we defined a cognitive-control-related connectivity index as the normalized difference between B cue and A cue connectivity: [SE-B(i)-SE-A(i)]/[SE-B(i)+SE-A(i)], where SE-A (i) and SE-B (i) refer to the edge-wise connectivity values for edge i during A cue and B cue trials, respectively. Positive values on this scale reflect greater connectivity during trials requiring cognitive control (i.e., B > A cue). Similarly, we derived a behavioral measure of cognitive control as the normalized difference between BX and AX trial accuracy and RT [i.e., (BX − AX)/(BX + AX)]. For the accuracy scale, higher values reflect better cognitive control performance (i.e., relatively more accurate responses); for the RT scale, higher values reflect poorer cognitive control performance (i.e., relatively slower responding).
