Dysconnectivity of multiple resting-state networks in patients with schizophrenia who have persistent auditory verbal hallucinations

Background: functional neuroimaging studies on schizophrenia have suggested abnormal task-related functional connectivity in patientswith schizophrenia who have auditory verbal hallucinations (avhs). however,little is known about intrinsic functional connectivityin these patients. methods: between january 2009 and february 2010,we studied patients with schizophrenia who had persistent andtreatment-refractory avhs in comparison with healthy controls. using functional magnetic resonance imaging,we studied the functionalconnectivity of multiple resting state networks (rsns) and their relation to symptom severity. we analyzed the data using a spatial groupindependent component analysis,and we used random-effects t tests to compare spatial components between groups. results: therewere 10 patients and 14 controls enrolled in this study. in total,16 rsns were identified,from which we selected 4 networks of interestfor further analyses. within a speech-related network,patients showed increased connectivity in bilateral temporal regions and decreasedconnectivity in the cingulate cortex. within 2 additional rsns associated with attention and executive control,respectively,patientsexhibited abnormal connectivity in the precuneus and right lateral prefrontal areas. we found correlations between measures ofavh severity and functional connectivity of the left anterior cingulate,left superior temporal gyrus and right lateral prefrontal cortex.limitations: the relatively small sample size,the patients' use of antipsychotic medication and the lack of a clinical control group haveto be considered as potential limitations. conclusion: our findings indicate that disrupted intrinsic connectivity of a speech-related networkcould underlie persistent avhs in patients with schizophrenia. in addition,the occurrence of hallucinatory symptoms seems to modu -late rsns associated with attention and executive control. © 2011 canadian medical association.