Intelligent Medical Research Center, Institute of Automation, Chinese Academy of Sciences, Beijing, 100190, China.
Psychiatry Res. 2012 May 31;202(2):118-25. doi: 10.1016/j.pscychresns.2012.03.002. Epub 2012 Jun 12.
Recent studies have shown that cognitive and memory decline in patients with Alzheimer's disease (AD) is coupled with losses of small-world attributes. However, few studies have investigated the characteristics of the whole brain networks in individuals with mild cognitive impairment (MCI). In this functional magnetic resonance imaging (fMRI) study, we investigated the topological properties of the whole brain networks in 18 AD patients, 16 MCI patients, and 18 age-matched healthy subjects. Among the three groups, AD patients showed the longest characteristic path lengths and the largest clustering coefficients, while the small-world measures of MCI networks exhibited intermediate values. The finding was not surprising, given that MCI is considered to be the prodromal stage of AD. Compared with normal controls, MCI patients showed decreased nodal centrality mainly in the medial temporal lobe as well as increased nodal centrality in the occipital regions. In addition, we detected increased nodal centrality in the medial temporal lobe and frontal gyrus, and decreased nodal centrality mainly in the amygdala in MCI patients compared with AD patients. The results suggested a widespread rewiring in AD and MCI patients. These findings concerning AD and MCI may be an integrated reflection of reorganization of the brain networks accompanied with the cognitive decline that may lead to AD.
最近的研究表明，阿尔茨海默病（AD）患者的认知和记忆下降与小世界属性的丧失有关。然而，很少有研究调查轻度认知障碍（MCI）个体的整个大脑网络的特征。在这项功能磁共振成像（fMRI）研究中，我们研究了 18 名 AD 患者、16 名 MCI 患者和 18 名年龄匹配的健康受试者的整个大脑网络的拓扑特性。在这三组中，AD 患者表现出最长的特征路径长度和最大的聚类系数，而 MCI 网络的小世界度量值表现出中间值。这一发现并不奇怪，因为 MCI 被认为是 AD 的前驱阶段。与正常对照组相比，MCI 患者的节点中心性主要在颞叶内侧区域下降，而在枕叶区域的节点中心性增加。此外，与 AD 患者相比，我们在 MCI 患者的颞叶内侧和额回中检测到节点中心性增加，而在杏仁核中检测到节点中心性降低。这些结果表明 AD 和 MCI 患者的大脑网络存在广泛的重新布线。这些关于 AD 和 MCI 的发现可能是伴随认知能力下降而导致 AD 的大脑网络重组的综合反映。
