Department of Medical Imaging, Jinan Military General Hospital, Shandong, People's Republic of China.
Brain Cogn. 2013 Oct;83(1):121-31. doi: 10.1016/j.bandc.2013.07.013. Epub 2013 Aug 17.
In this study, we simulated environmental heat exposure to 18 participants, and obtained functional magnetic resonance image (fMRI) data during resting state. Brain functional networks were constructed over a wide range of sparsity threshold according to a prior atlas dividing the whole cerebrum into 90 regions. Results of graph theoretical approaches showed that although brain networks in both normal and hyperthermia conditions exhibited economical small-world property, significant alterations in both global and nodal network metrics were demonstrated during hyperthermia. Specifically, a lower clustering coefficient, maintained shortest path length, a lower small-worldness, a lower mean local efficiency were found, indicating a tendency shift to a randomized network. Additionally, significant alterations in nodal efficiency were found in bilateral gyrus rectus, bilateral parahippocampal gyrus, bilateral insula, right caudate nucleus, bilateral putamen, left temporal pole of middle temporal gyrus, right inferior temporal gyrus. In consideration of physiological system changes, we found that the alterations of normalized clustering coefficient, small-worldness, mean normalized local efficiency were significantly correlated with the rectal temperature alteration, but failed to obtain significant correlations with the weight loss. More importantly, behavioral attention network test (ANT) after MRI scanning showed that the ANT effects were altered and correlated with the alterations of some global metrics (normalized shortest path length and normalized global efficiency) and prefrontal nodal efficiency (right dorsolateral superior frontal gyrus, right middle frontal gyrus and left orbital inferior frontal gyrus), implying behavioral deficits in executive control effects and maintained alerting and orienting effects during passive hyperthermia. The present study provided the first evidence for human brain functional disorder during passive hyperthermia according to graph theoretical analysis using resting-state fMRI.
在这项研究中，我们模拟了环境热暴露对 18 名参与者的影响，并在静息状态下获得了功能磁共振成像（fMRI）数据。根据将整个大脑分为 90 个区域的先验图谱，在广泛的稀疏阈值范围内构建了脑功能网络。图论方法的结果表明，尽管正常和高热条件下的大脑网络都表现出经济的小世界特性，但在高热期间，全局和节点网络指标都发生了显著变化。具体来说，发现聚类系数降低，最短路径长度保持不变，小世界性降低，平均局部效率降低，表明网络向随机化转变的趋势。此外，还发现双侧直回、双侧海马旁回、双侧岛叶、右侧尾状核、双侧壳核、左颞中回颞极、右侧下颞叶的节点效率发生了显著变化。考虑到生理系统的变化，我们发现归一化聚类系数、小世界性、平均归一化局部效率的变化与直肠温度的变化显著相关，但与体重减轻无关。更重要的是，MRI 扫描后的行为注意网络测试（ANT）显示，ANT 效应发生了变化，并与一些全局指标（归一化最短路径长度和归一化全局效率）和前额叶节点效率（右侧背外侧额上回、右侧额中回和左侧眶额下回）的变化相关，表明在被动性高热期间执行控制效应的行为缺陷和保持警觉和定向效应。本研究首次根据静息态 fMRI 的图论分析，为人类大脑在被动性高热期间的功能障碍提供了证据。
