Disordered brain connectivity at cortical level, generally defined as failure of effective functional integration within and between brain areas, has been proposed as a core deficit of schizophrenia. This conclusion is based on neuroimaging evidence on structural, functional, and effective brain connectivity (Friston, 1998; Ribolsi et al., 2009; Schmitt et al., 2011). Structural Connectivity (SC) refers to the anatomical substrate of defined fiber pathways connecting different brain regions (Koch et al., 2002), whereas Functional Connectivity (FC) is defined as the temporal correlation of the activities of different cortical/brain regions (Fingelkurts et al., 2005). The definition of Effective Connectivity (EC) has been more contentious (Horwitz, 2003), referring to direct or indirect influence that one neural system exerts over another (Friston, 2011).
