Structural and Functional Characteristics of the Dorsolateral Prefrontal Cortex in Schizophrenia Spectrum Disorders and Their Associations with Onset Age

Background: the dorsolateral prefrontal cortex (DLPFC) is one of the latest brain structures to mature during the ontogeny, and its structural and functional abnormalities play an important role in the pathogenesis of schizophrenia. As schizophrenia spectrum disorders usually start before the complete brain maturation and their earlier onset is coupled with worse prognosis, we suggested that earlier illness onset is related to more pronounced aberrations of the DLPFC. The aim of study was to analyze the associations of the onset age of schizophrenia spectrum disorders with structural and functional characteristics of the DLPFC that differentiated patients with schizophrenia spectrum disorders from healthy controls. Patients and methods: male patients with a diagnosis of schizophrenia spectrum disorders (n = 82) and healthy controls (n = 86) underwent structural MRI and functional resting-state fMRI. Cortical thickness and whole-brain functional connectivity of the DLPFC as well as local coherence and amplitude of low-frequency fluctuations of haemodynamic signal in the DLPFC were analyzed. Results: patients demonstrated a decreased gray matter thickness in the DLPFC bilaterally along with aberrant (predominantly decreased) functional connectivity of the DLPFC with other brain structures in each hemisphere. These measures were not associated with the age of illness onset. Conclusions: structural and functional abnormalities revealed in this study coincide with conventional view on the DLPFC as one of the key regions in schizophrenia spectrum disorders pathogenesis, however, these aberrations were not related to the age of psychosis onset. Possible interpretations of our results and limitations of the study are discussed in the article.