Aberrant Brain Connectivity in Schizophrenia Detected via a Fast Gaussian Graphical Model

Schizophrenia (SZ) is a chronic and severe mental disorder that affects how a person thinks, feels, and behaves. It has been proposed that this disorder is related to disrupted brain connectivity. With the development of functional magnetic resonance imaging (fMRI), further exploration of brain connectivity was made possible and this hypothesis has been verified. Region-based networks are commonly used for mapping brain connectivity. However, they fail to illustrate the connectivity within regions of interest (ROIs) and lose precise location information. Voxel-based networks provide higher precision, but are difficult to construct and interpret due to the high dimensionality of the data. In this paper, we adopt a novel high-dimensional Gaussian Graphical Model (GGM) -- $\psi$ -learning method, which can help ease computational burden and provide more accurate inference for underlying networks. This method has been proved to be an equivalent measure of the partial correlation coefficient and thus is flexible for network comparison through statistical tests. The fMRI data we used were collected by the Mind Clinical Imaging Consortium (MCIC) using an auditory task in which there are 92 SZ patients and 116 healthy controls. We compared the networks at three different scales by using global measurements, community structure, and edge-wise comparisons within the networks. Results reveal, at the highest resolution, sets of distinct aberrant patterns for the SZ patients and more precise local structures are provided within ROIs for further investigation.