Cortical thinning in cingulate and occipital cortices in first episode schizophrenia

Background: Postmortem studies examining discrete regions show reduced cortical thickness in schizophrenia. Computational image analysis methods allow spatially detailed cortical thickness measurements across the entire cortex in 3D, but have not addressed thickness changes in cingulate or other cortices bordering the medial walls of the cerebral hemispheres in first episode schizophrenia. Methods: Magnetic resonance images and cortical pattern matching methods were used to compare gray matter thickness, measureed at sub-voxal resolution at thousands of spatially equivalent locations on the medial hemispheric surfaces, between 72(51m/21f) first episode schizophrenia patients and 78(37m/41f) healthy controls similar in age. Group differences were mapped in 3D, and their overall significance was confirmed by permutation testing. Results: Patients with little or no prior antipsychotic medication treatments showed significant coritical thinning within cingulate, occipital and frontopolar cortices with no significant increased in any cortical location. Regional sex differences were observed with pronounced thinnig in the left paracentral lobule and right posterior cingulate in male and female patients respectively compared to same sex controls. Conclusions: Cortical thinning may correspond to cytoarchitectural and neurochemical abnormalities observed in similar anatomic locations and may underlie systems-wise disturbances that include hetermodal association cortices, where cotrical thinning has been perviously observed in first episode schizophrenia.