Superimposed against a pervasive and generalized functional connectivity deficit, patients showed a specific cognitive-control related connectivity impairment in a subnetwork of seven connections linking eight regions located in frontal and parietal cortex. For each connection in this network, control subjects generally showed increased connectivity in the B cue condition, whereas patients showed the reverse pattern (i.e., A > B cue connectivity). These findings complement and extend prior activation- and connectivity-based studies of the AX Continuous Performance Task in schizophrenia (27,29,67,68) by characterizing network abnormalities at a whole-brain level and mapping the specific dysfunctional subnetwork associated with cognitive control performance in patients. The importance of frontoparietal dysfunction for understanding cognitive control deficits in schizophrenia is underscored by the convergence of findings between this past work and our own.
