Classification of schizophrenic patients and healthy controls using multiple spatially independent components of structural MRI data

Abstract

Several meta-analyses were recently conducted in attempts to identify the core brain regions exhibiting pathological changes in schizophrenia, which could potentially act as disease markers. Based on the findings of these meta-analyses, we developed a multivariate pattern analysis method to classify schizophrenic patients and healthy controls using structural magnetic resonance imaging (sMRI) data. Independent component analysis (ICA) was used to decompose gray matter density images into a set of spatially independent components. Spatial multiple regression of a region of interest (ROI) mask with each of the components was then performed to determine pathological patterns, in which the voxels were taken as features for classification. After dimensionality reduction using principal component analysis (PCA), a nonlinear support vector machine (SVM) classifier was trained to discriminate schizophrenic patients from healthy controls. The performance of the classifier was tested using a 10-fold cross-validation strategy. Experimental results showed that two distinct spatial patterns displayed discriminative power for schizophrenia, which mainly included the prefrontal cortex (PFC) and subcortical regions respectively. It was found that simultaneous usage of these two patterns improved the classification performance compared to using either of them alone. Moreover, the two pathological patterns constitute a prefronto-subcortical network, suggesting that schizophrenia involves abnormalities in networks of brain regions.

Keywords

schizophrenia / discriminative analysis / gray matter network / independent component analysis (ICA) / support vector machine (SVM)

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