Vecchio Fabrizio, Miraglia Francesca, Piludu Francesca, Granata Giuseppe, Romanello Roberto, Caulo Massimo, Onofrj Valeria, Bramanti Placido, Colosimo Cesare, Rossini Paolo Maria
Brain Connectivity Laboratory, IRCCS San Raffaele Pisana, Via Val Cannuta, 247, 00166, Rome, Italy.
IRCCS Centro Neurolesi Bonino-Pulejo, Messina, Italy.
Brain Imaging Behav. 2017 Apr;11(2):473-485. doi: 10.1007/s11682-016-9528-3.
Brain imaging plays an important role in the study of Alzheimer's disease (AD), where atrophy has been found to occur in the hippocampal formation during the very early disease stages and to progress in parallel with the disease's evolution. The aim of the present study was to evaluate a possible correlation between "Small World" characteristics of the brain connectivity architecture-as extracted from EEG recordings-and hippocampal volume in AD patients. A dataset of 144 subjects, including 110 AD (MMSE 21.3) and 34 healthy Nold (MMSE 29.8) individuals, was evaluated. Weighted and undirected networks were built by the eLORETA solutions of the cortical sources' activities moving from EEG recordings. The evaluation of the hippocampal volume was carried out on a subgroup of 60 AD patients who received a high-resolution T1-weighted sequence and underwent processing for surface-based cortex reconstruction and volumetric segmentation using the Freesurfer image analysis software. Results showed that, quantitatively, more correlation was observed in the right hemisphere, but the same trend was seen in both hemispheres. Alpha band connectivity was negatively correlated, while slow (delta) and fast-frequency (beta, gamma) bands positively correlated with hippocampal volume. Namely, the larger the hippocampal volume, the lower the alpha and the higher the delta, beta, and gamma Small World characteristics of connectivity. Accordingly, the Small World connectivity pattern could represent a functional counterpart of structural hippocampal atrophying and related-network disconnection.
脑成像在阿尔茨海默病（AD）研究中发挥着重要作用，研究发现，在疾病的极早期阶段，海马结构就会出现萎缩，并随着疾病的发展而进展。本研究的目的是评估从脑电图记录中提取的大脑连接结构的“小世界”特征与AD患者海马体积之间可能存在的相关性。对一个包含144名受试者的数据集进行了评估，其中包括110名AD患者（简易精神状态检查表[MMSE]评分为21.3）和34名健康对照者（MMSE评分为29.8）。通过从脑电图记录中获取的皮质源活动的eLORETA解决方案构建加权无向网络。对60名AD患者的一个亚组进行了海马体积评估，这些患者接受了高分辨率T1加权序列扫描，并使用Freesurfer图像分析软件进行基于表面的皮质重建和体积分割处理。结果表明，从数量上看，右侧半球的相关性更强，但两个半球都呈现相同的趋势。α波段连接性呈负相关，而慢波（δ波）和快波（β波、γ波）波段与海马体积呈正相关。也就是说，海马体积越大，α波段连接性越低，而δ波、β波和γ波的“小世界”连接特征越高。因此，“小世界”连接模式可能代表了海马结构萎缩和相关网络断开的功能对应物。
