Chang Xiao, Shen Hui, Wang Lubin, Liu Zhening, Xin Wei, Hu Dewen, Miao Danmin
Department of Psychology, Fourth Military Medical University, Xi'an, Shannxi 710032, China.
College of Mechatronics and Automation, National University of Defense Technology, Changsha, Hunan 410073, China.
Brain Res. 2014 May 8;1562:87-99. doi: 10.1016/j.brainres.2014.03.024. Epub 2014 Mar 25.
The complex symptoms of schizophrenia have recently been linked to disrupted neural circuits and corresponding malfunction of two higher-order intrinsic brain networks: The default mode network (DMN) and the fronto-parietal network (FPN). These networks are both functionally heterogeneous and consist of multiple subsystems. However, the extent to which these subsystems make differential contributions to disorder symptoms and to what degree such abnormalities occur in unaffected siblings have yet to be clarified. We used resting-state functional MRI (rs-fMRI) to examine group differences in intra- and inter-connectivity of subsystems within the two neural networks, across a sample of patients with schizophrenia (n=24), their unaffected siblings (n=25), and healthy controls (n=22). We used group independent component analysis (gICA) to identify four network subsystems, including anterior and posterior portions of the DMN (aDMN, pDMN) as well as left- and right-lateralized portions of the FPN (lFPN, rFPN). Intra-connectivity is defined as neural coherence within a subsystem whereas inter-connectivity refers to functional connectivity between subsystems. In terms of intra-connectivity, patients and siblings shared dysconnection within the aDMN and two FPN subsystems, while both groups preserved connectivity within the pDMN. In terms of inter-connectivity, all groups exhibited positive connections between FPN and DMN subsystems, with patients having even stronger interaction between rFPN and aDMN than the controls, a feature that may underlie their psychotic symptoms. Our results implicate that DMN subsystems exhibit different liabilities to the disease risk while FPN subsystems demonstrate distinct inter-connectivity alterations. These dissociating manners between network subsystems explicitly suggest their differentiating roles to the disease susceptibility and manifestation.
精神分裂症的复杂症状最近被认为与神经回路紊乱以及两个高阶大脑固有网络——默认模式网络（DMN）和额顶叶网络（FPN）的相应功能失调有关。这些网络在功能上都是异质性的，并且由多个子系统组成。然而，这些子系统对疾病症状的不同贡献程度以及在未受影响的兄弟姐妹中这种异常的发生程度尚未明确。我们使用静息态功能磁共振成像（rs-fMRI）来检查精神分裂症患者（n = 24）、他们未受影响的兄弟姐妹（n = 25）和健康对照组（n = 22）样本中两个神经网络内子系统的内部和相互连接性的组间差异。我们使用组独立成分分析（gICA）来识别四个网络子系统，包括DMN的前部和后部（aDMN、pDMN）以及FPN的左侧和右侧部分（lFPN、rFPN）。内部连接性被定义为子系统内的神经相干性，而相互连接性是指子系统之间的功能连接性。在内部连接性方面，患者和兄弟姐妹在aDMN和两个FPN子系统中都存在连接中断，而两组在pDMN内都保持了连接性。在相互连接性方面，所有组在FPN和DMN子系统之间都表现出正连接，患者的rFPN和aDMN之间的相互作用甚至比对照组更强，这一特征可能是他们精神症状的基础。我们的结果表明，DMN子系统对疾病风险表现出不同的易感性，而FPN子系统表现出明显的相互连接性改变。网络子系统之间的这些分离方式明确表明了它们在疾病易感性和表现方面的不同作用。
