FC impairment in schizophrenia has been extensively investigated. Studies using functional Magnetic Resonance Imaging (fMRI) have shown abnormal FC both in first episode/early stage (Begre and Koenig, 2008) and in chronic schizophrenic patients (Lynall et al., 2010; Fitzsimmons et al., 2013; Wang et al., 2014). EEG studies, capitalizing on its high temporal resolution, have shown impaired FC in all frequencies bands of the EEG spectrum (Stephan et al., 2006). Transcranial magnetic stimulation (see for review Rogasch et al., 2014) and transcranial direct current stimulation (Hasan et al., 2013; Ribolsi et al., 2013) studies have identified altered inhibitory/excitatory properties of brain networks and of interhemispheric connectivity in schizophrenia. Finally, confirmation of the central role of disordered connectivity has also emerged from animal models of schizophrenia (Dickerson et al., 2010; Gruber et al., 2010).
