Disrupted thalamo-orbitofrontal but not fronto-temporal white matter connectivity in people with schizotypal personality disorder

Introduction Despite patients with schizophrenia showed the deficits in the fronto-temporal and thalamo-frontal connectivity, the white matter connectivity in patients with schizotypal personality disorder had not been systemically investigated. Methods This study involved 40 neuroleptic-naive patients with schizotypal personality disorder (SPD), 60 patients with schizophrenia (SCZ), and 100 healthy controls (HC), and scanned on the 3T MRI scanner. Probablistic tractography was performed using the FATCAT software in AFNI. The target brain regions (bilateral lateral frontal, medial frontal, orbitofrontal, temporal and thalamus) were extracted from the automated segmentation and cortical parcellation. Cross-sectional comparisons in mean fractional anisotropy (FA) performed on the thalamo-lateral frontal, thalamo-medial frontal, thalamo-orbitofrontal, lateral frontal-temporal and orbitofrontal-temporal pathway. We also analyzed the relationship between the white matter pathway and the Positive and Negative Syndrome Scale and GAF. Results The diffusion tensor imaging showed that SCZ and SPD had decreased FA in the left thalamo-orbitofrontal pathway. However, SPD showed no alteration in the fronto-temporal pathway, despite SCZ showed decreased FA in the left temporo-orbitofrontal pathway. In SCZ, there were significant correlations between FA value in the left temporo-orbitofrontal pathway and negative symptoms score in PANSS and GAF score. However, SPD showed the trend level relationship between the GAF score and FA value in the left temporo-orbitofrontal pathway. Conclusion These results suggest that the deficits in thalamo-frontal connectivity may be a trait marker of schizophrenia spectrum disorder, and the deficits in fronto-temporal connectivity may play a key role towards the vulnerability of psychosis.