## 2 Materials and Methods  
### Human Brain Data  
#### 2.1.1 Data Acquisition  
The data used in this study were dMRI, sMRI, and resting-state fMRI data from the Center of Biomedical Research Excellence (COBRE), available from the Collaborative Informatics and Neuroimaging Suite data exchange repository [31; 32] (coins.trendscenter.org/, accessed on 8 October 2018). All the three datasets include the same 86 HCs (average age: \(36.6\pm 12.1\) years) and 76 SZs (average age: \(36.9\pm 13.5\) years). All patients completed the Structured Clinical Interview for DSM-IV Axis I Disorders (SCID [33]) for diagnostic confirmation (consensus was reached by two research psychiatrists using the SCID-DSM-IV-TR, patient version) and evaluation for co-morbidities [34]. The battery of cognitive performance tests used was the MATRICS (Measurement and Treatment Research to Improve Cognition in Schizophrenia) Cognitive Battery, including seven cognitive domains: speed of processing, attention/vigilance, working memory, verbal learning, visual learning, reasoning, and problem solving, and social cognition. We performed two-sample \(t\)-tests on these cognitive scores from the HC and SZ subjects. Compared with healthy controls, SZs had a significantly lower cognitive performance on all domains, supporting the findings that patients diagnosed with schizophrenia have an abnormal cognitive function.  
DMRI data were collected along the anterior commisure-posterior commisure (AC-PC) line throughout the whole brain with a field of view (FOV) of \(256\times 256\) mm\({}^{2}\), a \(128\times 128\) matrix, 72 slices with a slice thickness of 2 mm (2 mm isotropic resolution), a number of excitations (NEX) of 1, echo time (TE) of 84 ms, and repetition time (TR) of 9000 ms. A multiple-channel radio-frequency (RF) coil was used, with GeneRalized Autocalibrating Partial Parallel Acquisition (GRAPPA) (X2), with 30 gradient directions with a b of 800 s/mm\({}^{2}\). The b = 0 experiment was repeated five times [35] and equally interspersed between the 30 gradient directions. The total scan time was about 6 min. This procedure was repeated twice to increase the signal-to-noise ratio (SNR).  
For the sMRI data collection, the echo planar imaging (EPI) slices were collected in a sequential ascending order on a Siemens 3 T TIM Trio scanner using a 12-channel head coil. A sagittal gradient echo scout image through the mid-line was obtained to prescribe oblique axial image slices that were parallel to the AC-PC line. To minimize the susceptibility artifact in the orbitofrontal area, oblique slices were used [36]. High-resolution T1-weighted images were acquired with a five-echo multi-echo magnetization-prepared rapid gradient-echo (MP-RAGE) sequence (TE = 1.64, 3.5, 5.36, 7.22, 9.08 ms, TR = 2.53 s, TI (inversion time) = 1.2 s, flip angle = \(7^{\circ}\), NEX = 1, slice thickness = 1 mm, FOV = 256 mm, resolution = \(256\times 256\)) for region of interest analyses and spatial normalization.  
The resting-state fMRI data were acquired using a conventional single-shot, gradient echo echo-planar pulse sequence with lipid suppression (TE = 29 ms; TR = 2000 ms; flip angle = \(75^{\circ}\); FOV = 240 mm; matrix size = \(64\times 64\); 33 slices; voxel size: \(3.75\times 3.75\times 4.55\) mm\({}^{3}\)). The first image of each run was removed to eliminate TI equilibrium effects [37].The participants were instructed to keep their eyes open during the scan and store passively at a central fixation cross for about 5 min.