BACKGROUND:Schizophrenia (SCZ) is a highly heritable disorder associated with brain connectivity changes. Although the mechanism of disease expression and vulnerability of SCZ have been reported by previous studies, the mechanism of resilience to SCZ based on the brain structural connectivity is poorly understood. The goal of the present study was to identify the structural brain connectivity related with the resilience to SCZ, which is defined here as the capacity to avoid or delay the onset of SCZ in unaffected siblings of SCZ probands.METHOD:We collected diffusion tensor imaging (DTI) data of 49 medication-naive, first-episode SCZ (FE-SCZ) patients, 56 unaffected siblings of SCZ probands (SIB-SCZ), and 90 healthy controls. Then we used graph theoretical approach to calculate the topological properties of the brain structural network, including global, subnetwork, and regional parameters. Finally, we compared the parameters between the three groups, and identified the brain structural network related to the resilience, vulnerability and disease expression to SCZ.RESULTS:With respect to resilience, only the SIB-SCZ showed significantly increased connectivity in the subnetworks of the left cuneus-precuneus and left posterior cingulate gyrus-precuneus, and in brain areas of right supramarginal gyrus and right inferior temporal gyrus. With respect to vulnerability, both the FE-SCZ and SIB-SCZ had decreased cluster coefficients and local efficiency, and decreased nodal efficiency in the right medial superior frontal gyrus and right medial orbital superior frontal gyrus compared with the healthy controls. With respect to disease expression, only the FE-SCZ group showed decreased or increased global, subnetwork, and nodal connectivity in broader brain regions compared with the healthy controls.CONCLUSION:Difference in the topological properties of brain structural connectivity not only reflect the underlying mechanism of vulnerability but also that of resilience to schizophrenia. Alteration in the brain structural connectivity associating with resilience and disease expression may contribute to the onset of SCZ.

Objective To investigate the neurocognitive functions in the healthy siblings of patients with schizophrenia.Methods Thirty healthy siblings of patients with schizophrenia and forty-three normal controls,collected in our hospital from October 2010 to April 2012,were assessed with five neurocognitive tests.These tests included Stroop Test,WAIS-Ⅲ Symbolic Coding,WAIS-Ⅲ Symbol Search,Paced Auditory Serial Addition Task (PASAT) and Wisconsin Card Sorting Tests (WCST).Results The results of some neurocognitive tests such as word of Stroop Test (P=0.016),word-color of Stroop Test (P=0.001),correct number of WAIS-Ⅲ symbol search (P=0.005),incorrect number of WAIS-Ⅲ symbol search (P=0.025),total score of WAIS-Ⅲ symbol search (P=0.041),correct number of WCST (P=0.015),randomly incorrect number of WCST (P=0.005) and completed grouping numbers of WCST (P=0.041) in the healthy siblings of patients with schizophrenia were significantly worse as compared with those in the normal controls.Conclusion The healthy siblings of patients with schizophrenia have general neurocognitive defects,such as executive function and information processing speed.

OBJECTIVE:To explore the diffusion tensor imaging (DTI) features of white matter in healthy siblings of schizophrenics.METHODS:Twenty healthy siblings of schizophrenics and 45 healthy controls without a family history of mental disorder. They responded to advertised recruitment during December 2009 and March 2012. All participants underwent diffusion weighted magnetic resonance images with a single-shot echo planar imaging (EPI) sequence aligned to straight axial plane. The fractional anisotropy (FA) images of two groups underwent two-sample t-test with SPM5 software.RESULTS:The healthy siblings of schizophrenics demonstrated a significant decrease of regional white matter FA values in right anterior cingulated (MNI: x = 9, y = 43, z = 4; cluster = 106).CONCLUSION:Reduced white matter integrity in right anterior cingulated may be a risk actor of schizophrenia.