Effective connectivity of the posterior cingulate and medial prefrontal cortices relates to working memory impairment in schizophrenic and bipolar patients

• Published in: Schizophrenia research 2014-09, Vol.158 (1), p.85-90
• Main Authors: Wu, Guowei, Wang, Yunxia, Mwansisya, Tumbwene E, Pu, Weidan, Zhang, Huiran, Liu, Chang, Yang, Qing, Chen, Eric Y.H, Xue, Zhimin, Liu, Zhening, Shan, Baoci
• Format: Article
• Language: English
• Subjects: Adult; Bipolar disorder; Bipolar Disorder - drug therapy; Bipolar Disorder - physiopathology; Brain Mapping; Cognition; Dynamic causal modeling; Effective connectivity; Female; Functional Laterality; Gyrus Cinguli - physiopathology; Humans; Magnetic Resonance Imaging; Male; Memory Disorders - physiopathology; Memory, Short-Term - physiology; Models, Neurological; Neural Pathways - physiopathology; Neuropsychological Tests; Photic Stimulation; Prefrontal Cortex - physiopathology; Psychiatry; Schizophrenia; Schizophrenia - drug therapy; Schizophrenia - physiopathology; Signal Processing, Computer-Assisted; Visual Perception - physiology; Young Adult
• ISSN: 0920-9964; 1573-2509
• DOI: 10.1016/j.schres.2014.06.033

Abstract Background Schizophrenia (SZ) and bipolar I disorder (BD) share many overlapping clinical features, confounding the current diagnostic systems. Recent studies suggest the posterior cingulate (PCC) and medial prefrontal (MPFC) cortices that are involved in SZ and BD pathophysiology. However, the roles of PCC and MPFC in providing specific distinctive and shared neural substrates between these two disorders remain largely unknown. Examining the neurophysiologic mechanism of these diseases may help explain the clinical observations and differentiate the two disorders. Methods We used the Dynamic Casual Modeling (DCM), which is capable of eliciting hidden neuronal dynamics and reveal cross-regulation of multiple neuronal systems, to characterize the pattern of disrupted effective connectivity in the left PCC–MPFC circuit during working memory tasks in 36 SZ and 20 BD patients as well as 29 healthy controls. Results Compared to the healthy controls, both SZ and BD patient groups exhibited significant negative effective connectivity from the left MPFC to PCC. The negative effective connectivity was more remarkable in schizophrenic patients. Only patients with BD differed from healthy controls with positive effective connectivity from the left PCC to MPFC. Conclusions Whole brain analysis revealed deactivation of the left PCC and MPFC across all patient groups. This study provides new insight that changes in effective connectivity of the left MPFC to left PCC circuit during working memory processing may be a core pathophysiological feature distinguishing SZ from BD.