White Matter Integrity of the Three Subdivisions of the Superior Longitudinal Fasciculi in First-Episode Psychosis Patients.

The superior longitudinal fasciculus (SLF) is a white matter (WM) bundle connecting the frontal and parietal lobes. SLF subdivisions have distinct functions (e.g., attention, working memory, and language processing), and abnormalities in specific subdivisions may differentially contribute to the pathophysiology of first-episode psychosis (FEP). However, previous diffusion magnetic resonance imaging (MRI) studies have not fully examined SLF subdivisions, limiting our understanding of their role in FEP patients. The aim of this study was to assess whether WM integrity differs in SLF subdivisions between FEP patients and healthy controls (HCs) using advanced diffusion tensor imaging. 3T diffusion MRI scans were obtained from 39 FEP patients and 110 HCs. Deterministic tractography was used to reconstruct the three SLF subdivisions (SLF I, II, and III). We analyzed the fractional anisotropy (FA), mean diffusivity (MD), and radial diffusivity (RD) of these subdivisions and compared the results between FEP patients and HCs. There were no significant group differences in the FA, MD, or RD between the FEP patients and HCs. No significant differences in WM integrity between FEP patients and HCs were found. These results suggest that significant WM changes may develop later in the disease course rather than in the early stages of psychotic disorders such as FEP.