Department of Neuropsychiatry, Affiliated ZhongDa Hospital of Southeast University, Nanjing, PR China.
Neuroimage. 2012 Oct 15;63(1):320-7. doi: 10.1016/j.neuroimage.2012.06.062. Epub 2012 Jul 6.
Abnormalities of functional connectivity in the default mode network (DMN) recently have been reported in patients with amnestic mild cognitive impairment (aMCI), Alzheimer's disease (AD) or other psychiatric diseases. As such, these abnormalities may be epiphenomena instead of playing a causal role in AD progression. To date, few studies have investigated specific brain networks, which extend beyond the DMN involved in the early AD stages, especially in aMCI. The insula is one site affected by early pathological changes in AD and is a crucial hub of the human brain networks. Currently, we explored the contribution of the insula networks to cognitive performance in aMCI patients. Thirty aMCI and 26 cognitively normal (CN) subjects participated in this study. Intrinsic connectivity of the insula networks was measured, using the resting-state functional connectivity fMRI approach. We examined the differential connectivity of insula networks between groups, and the neural correlation between the altered insula networks connectivity and the cognitive performance in aMCI patients and CN subjects, respectively. Insula subregional volumes were also investigated. AMCI subjects, when compared to CN subjects, showed significantly reduced right posterior insula volumes, cognitive deficits and disrupted intrinsic connectivity of the insula networks. Specifically, decreased intrinsic connectivity was primarily located in the frontal-parietal network and the cingulo-opercular network, including the anterior prefrontal cortex (aPFC), anterior cingulate cortex, operculum, inferior parietal cortex and precuneus. Increased intrinsic connectivity was primarily situated in the visual-auditory pathway, which included the posterior superior temporal gyrus and middle occipital gyrus. Conjunction analysis was performed; and significantly decreased intrinsic connectivity in the overlapping regions of the anterior and posterior insula networks, including the bilateral aPFC, left dorsolateral prefrontal cortex, dorsomedial prefrontal cortex, and anterior temporal pole was found. Furthermore, the disrupted intrinsic connectivity was associated with episodic memory (EM) deficits in the aMCI patients and not in the CN subjects. These findings demonstrated that the functional integration of the insula networks plays an important role in the EM process. They provided new insight into the neural mechanism underlying the memory deficits in aMCI patients.
静息态功能磁共振成像研究岛叶网络的内在连接对遗忘型轻度认知障碍患者认知表现的影响
岛叶网络的功能连接异常最近在遗忘型轻度认知障碍(aMCI)、阿尔茨海默病(AD)或其他精神疾病患者中被报道。因此，这些异常可能只是一种表象，而不是 AD 进展的因果关系。迄今为止，很少有研究调查特定的脑网络，这些网络扩展到 AD 早期阶段以外的网络，特别是在 aMCI 中。岛叶是 AD 早期病理变化影响的一个部位，是人类大脑网络的关键枢纽。目前，我们探讨了岛叶网络对 aMCI 患者认知表现的贡献。30 名 aMCI 和 26 名认知正常(CN)受试者参加了这项研究。使用静息态功能连接 fMRI 方法测量岛叶网络的内在连接。我们分别在两组之间检查了岛叶网络的差异连接，以及改变的岛叶网络连接与 aMCI 患者和 CN 受试者认知表现之间的神经相关性。还研究了岛叶亚区体积。与 CN 受试者相比，aMCI 受试者的右侧后岛叶体积明显减小，认知功能减退，岛叶网络的内在连接受到干扰。具体而言，内在连接的减少主要位于额顶网络和扣带前回网络，包括前前额叶皮层(aPFC)、前扣带回、脑岛盖、顶下小叶和楔前叶。内在连接的增加主要位于视觉听觉通路，包括后上颞叶和中枕叶。进行了联合分析；在前后岛叶网络重叠区域发现显著降低的内在连接，包括双侧 aPFC、左侧背外侧前额叶皮层、背内侧前额叶皮层和前颞极。此外，内在连接的中断与 aMCI 患者的情景记忆(EM)缺陷相关，而与 CN 受试者无关。这些发现表明，岛叶网络的功能整合在 EM 过程中起着重要作用。它们为 aMCI 患者记忆缺陷的神经机制提供了新的见解。
