Selective Functional Disconnection of the Dorsal Subregion of the Temporal Pole in Schizophrenia

Although extensive resting-state functional connectivity (rsFC) changes have been reported in schizophrenia, rsFC changes in the temporal pole (TP) remain unknown. The TP contains several subregions with different connection patterns; however, it is not known whether TP subregions are differentially affected in schizophrenia. Sixty-six schizophrenia patients and 76 healthy comparison subjects underwent resting-state fMRI using a sensitivity-encoded spiral-in (SENSE-SPIRAL) imaging sequence to reduce susceptibility-induced signal loss and distortion. The TP was subdivided into the dorsal (TPd) and ventral (TPv) subregions. Mean fMRI time series were extracted for each TP subregion and entered into a seed-based rsFC analysis. Direct between-group comparisons revealed reduced rsFC between the right TPd and brain regions involved in language processing and multisensory integration in schizophrenia, including the left superior temporal gyrus, left mid-cingulate cortex, and right insular cortex. The rsFC changes of the right TPd in schizophrenia were independent of the grey matter reduction of this subregion. Moreover, these rsFC changes were unrelated to illness severity, duration of illness and antipsychotic medication dosage. No significant group differences were observed in the rsFC of the left TPd and bilateral TPv subregions. These findings suggest a selective (the right TPd) functional disconnection of TP subregions in schizophrenia.