Resting-state functional network correlates of psychotic symptoms in schizophrenia

Schizophrenia has been associated with aberrant intrinsic functional organization of the brain but the relationship of such deficits to psychopathology is unclear. In this study, we investigated associations between resting-state networks and individual psychopathology in sixteen patients with paranoid schizophrenia and sixteen matched healthy control participants. We estimated whole-brain functional connectivity of multiple networks using a combination of spatial independent component analysis and multiple regression analysis. Five networks (default-mode, left and right fronto-parietal, left fronto-temporal and auditory networks) were selected for analysis based on their involvement in neuropsychological models of psychosis. Between-group comparisons and correlations to psychopathology ratings were performed on both spatial (connectivity distributions) and temporal features (power-spectral densities of temporal frequencies below 0.06 Hz). Schizophrenia patients showed aberrant functional connectivity in the default-mode network, which correlated with severity of hallucinations and delusions, and decreased hemispheric separation of fronto-parietal activity, which correlated with disorganization symptoms. Furthermore, the severity of positive symptoms correlated with functional connectivity of fronto-temporal and auditory networks. Finally, default-mode and auditory networks showed increased spectral power of low frequency oscillations, which correlated with positive symptom severity. These results are in line with findings from studies that investigated the neural correlates of positive symptoms and suggest that psychopathology is associated with aberrant intrinsic organization of functional brain networks in schizophrenia.