In our study, schizophrenia was associated with deficient recruitment of the anterior cingulate gyrus into the DMN, consistent with a large schizophrenia literature (Benes 1998). In addition, there was a striking recruitment of multiple basal ganglia regions bilaterally into the DMN in schizophrenia. Circuit-level abnormalities in the basal ganglia have been reported in schizophrenia (Chang et al., 2007; Menon et al., 2001) and may be involved in problems of dynamic adjustment of control and cognitive sequencing (Kerns et al., 2008)(Kerns, et al. 2008). The abnormal recruitment of basal ganglia regions in schizophrenia is likely coupled with a loss of recruitment of the anterior cingulate cortex because the two are anatomically closely connected. The two findings may relate through a breakdown in executive functioning in schizophrenia. Finally, the frontal polar cortex was strongly recruited into the DMN in schizophrenia. This brain region is implicated in integrating the outcomes of two or more cognitive operations in pursuit of behavioral goals (Ramnani and Owen 2004), but more work is needed to confirm abnormalities in this process in schizophrenia.
