Schizophrenia and the brain's control network: aberrant within- and between-network connectivity of the frontoparietal network in schizophrenia.

The deficit of executive control is a core feature of schizophrenia, and as such, it provides hints for the neural signature of this devastating mental illness. The frontoparietal network (FPN) is a newly defined network important for various tasks requiring executive control. This study aims to investigate both the within- and between-network connectivity of the FPN in schizophrenia using functional connectivity MRI (fcMRI). Thirty-six subjects with schizophrenia and thirty-six healthy controls were enrolled. Each subject received resting fMRI scanning, clinical evaluations and cognitive examinations. Twenty-two regions of interest (ROIs) in the key hubs of the FPN were defined according to the functional connectivity map of the left and right dorsolateral prefrontal cortex (dlPFC) and included the bilateral frontal pole, inferior parietal lobe (IPL), insula, dorsomedial prefrontal cortex (dmPFC), middle cingulate cortex (mCC), precuneus, caudate, thalamus and cerebellum. Between-group comparisons were conducted using both multiple ROI-based and brain-wise analyses. The ROI-based analysis revealed that the schizophrenic participants were associated with a prominent cortico-subcortical disconnection within the FPN. Further brain-wise analyses demonstrated that the schizophrenia patients showed increased functional connectivity between several ROIs in the FPN and regions belonging to the primary sensory processing or default mode networks. These results indicated that schizophrenia is associated with both within- and between-network dysconnectivity of the FPN. Together with our previous findings of the cortico-striatal disconnection of the cingulo-opercular network, we suggest that the brain's control networks may play an important role in the neural mechanisms of schizophrenia.