Morphometry of structural disconnectivity indicators in subjects at risk and in age-matched patients with schizophrenia

Structural disconnectivity has been hypothesized as being accountable for the pathophysiology of schizophrenia. Morphometric variables suitable for the empirical study of disconnectivity were studied aiming at the research question whether empirical indicators for disconnectivity are already informative in subjects at risk (SAR) and in young matched patients diagnosed with schizophrenia (SZ). In MRI data of subjects of the two diagnostic groups SZ and SAR, the size of the corpus callosum (CC) as indicator for interhemispherical long distance connections and the gyrification index (GI) as indicator for cortico-cortical connections were analyzed compared to a healthy controls (HC). Each subgroup consists of 21 subjects matched for sex and age. Measurements of the CC and GI were estimated in manually performed tracing procedures. GI data revealed significant differences between the diagnostic groups of both SAR and SZ as compared to HC in the frontal and parietal cortices. Measurements of total CC yielded no significant differences between diagnostic groups. The results are suggestive for impaired cortico-cortical connections as indicated by gyrification changes in SZ and also in SAR, whereas interhemispherical connectivity at the same time appears to be unaffected.