Supra-regional brain systems and the neuropathology of schizophrenia

At what levels of brain organization might pathological change in schizophrenia be anatomically expressed: global, regional or supraregional? We hypothesised that brain structure reflects a set of supra-regional anatomical systems with common developmental influences. We conducted an exploratory analysis to identify supraregional brain systems and to investigate whether abnormal brain architecture in schizophrenia is manifested within one or more of these systems. Magnetic resonance (MR) images were acquired from 27 patients with schizophrenia and 37 control subjects. After segmentation and registration of each individual MRI dataset in the standard space of Talairach and Tournoux, grey matter and ventricular-cerebrospinal fluid (CSF) maps were automatically parcellated into 104 regions. We used principal components analysis of the multiple regional grey matter and ventricular-CSF measurements, on all 64 subjects, to extract the five main normative supra-regional systems. The first two of these components represented global variation in grey matter and ventricular-CSF regional measures. We interpreted the other three components as representing supra-regional systems comprising: a frontal-parietal system, a frontal-temporal system and a frontal-basal ganglia system. Schizophrenic group mean scores on the first component (global grey matter-ventricular contrast) and fourth component (frontal-temporal system) were significantly reduced compared to controls. These results suggest that pathological change in schizophrenia may be expressed at two mutually independent levels of anatomical organization: global change in a grey matter/ventricular system and supra-regional change in a frontal-temporal system.