Higher prefrontal cortical thickness in high schizotypal personality trait

A model of schizophrenia-spectrum disorders hypothesized that schizotypy shares biomarkers with schizophrenia but due to protective factors such as a greater prefrontal cortex those individuals have a reduced vulnerability to schizophrenia. In contrast to previous studies exploring volumetric brain correlates of schizotypy focussing on clinical samples or relying on between-group comparisons we measured cortical thickness and correlated it with the expression of schizotypal personality traits in a mentally healthy sample. We acquired high-resolution MRI scans from 34 subjects and used FreeSurfer to model the grey white and pial surfaces for each individual cortex in order to compute the distance between these surfaces to obtain a measure of cortical thickness. Differences in cortical thickness were correlated with positive and negative factors of schizotypy as assessed by means of the Schizotypal Personality Questionnaire. We found a significant positive correlation between right dorso-lateral prefrontal cortex (DLPFC) and right dorsal premotor cortex/frontal eye fields (dPMC/FEF) and the total schizotypy score, between right DLPFC and the positive factor, and between right temporo-parietal junction and the negative factor of schizotypy. The volume of thalamus was negatively correlated with schizotypy. A significant negative correlation between thalamus volume and dPMC/FEF cortical thickness was observed. One may speculate that this finding is in line with the hypothesis of a compensatory role of greater prefrontal cortex in schizotypy in healthy populations. (C) 2012 Elsevier Ltd. All rights reserved.