Thalamic Shape Abnormalities in Antipsychotic Naïve Schizophrenia

Abstract

Background: Neurodevelopmental hypothesis of schizophrenia states abnormal pruning as one of the pathogenetic mechanism in schizophrenia. Though thalamic volume abnormalities have been documented, the shape differences of thalamus in antipsychotic-free schizophrenia in comparison with age- and sex-matched healthy volunteers need validation. Materials and Methods: We examined antipsychotic naïve schizophrenia patients (n=60) and age- and sex-matched healthy volunteers (n=44). The thalamic shape abnormalities were analyzed from their coded structural magnetic resonance imaging (MRI) data using three-dimensional automated image analysis software, FMRIB's (Oxford Center for the functional MRI of the brain) tools-FIRST (FMRIB's Integrated Registration and Segmentation Tool) by creating deformable mesh model. Correlation with the psychopathology scores was carried out using F-statistics. Results: Patients with schizophrenia showed significant inward deformations in the regions corresponding to anterior, ventromedial, mediodorsal, and pulvinar nuclei. There was a direct correlation between negative syndrome score and the deformation in the right mediodorsal and right pulvinar nuclei. Conclusion: The inward deformations of thalamus in antipsychotic naive schizophrenia patients correspond to those nuclei which have reciprocal connections with frontal, superior temporal, and anterior cingulate regions and support the neurodevelopmental hypothesis of schizophrenia.