Bartolomei Fabrice, Bosma Ingeborg, Klein Martin, Baayen Johannes C, Reijneveld Jaap C, Postma Tjeerd J, Heimans Jan J, van Dijk Bob W, de Munck Jan C, de Jongh Arent, Cover Keith S, Stam Cornelis J
Department of Clinical Neurophysiology, VU University Medical Center, Amsterdam, The Netherlands.
Clin Neurophysiol. 2006 Sep;117(9):2039-49. doi: 10.1016/j.clinph.2006.05.018. Epub 2006 Jul 21.
Cerebral functions are based on the functional interactions between multiple distinct specialized regions of the brain. Functional interactions require anatomical connections as well as the synchronization of brain oscillations. The present work aims at evaluating the impact of brain tumours on spatial patterns of functional connectivity of the brain measured at rest by MEG.
We analyzed the statistical dependency (by computing the synchronization likelihood (SL, a measure of generalized synchronization)) between MEG signals at rest, in 17 patients with a brain tumour and in 15 healthy controls. Following an approach that derives from graph theory, we also analyzed the architectural properties of the networks by computing two parameters from the SL matrix, the cluster coefficient C and the characteristic path length L.
Alterations in synchronization levels were found in the patients and were not focal but involved intra-hemispheric connectivity. Effects were different considering the frequencies sub-bands, predominating in a decrease in high frequencies bands for long-distance connections and an increase in slower bands for local connectivity. In addition, graph analysis reveals changes in the normal "small-world" network architecture in addition to changes in synchronization levels with some differences according to the studied frequency sub-bands.
Brain tumours alter the functional connectivity and the "network" architecture of the brain. These alterations are not focal and effects are different considering the frequencies sub-bands.
These neurophysiological changes may contribute to the cognitive alterations observed in patients with brain tumours.
脑功能基于大脑多个不同专门区域之间的功能相互作用。功能相互作用需要解剖学连接以及脑振荡的同步。本研究旨在评估脑肿瘤对静息状态下通过脑磁图（MEG）测量的大脑功能连接空间模式的影响。
我们分析了17例脑肿瘤患者和15名健康对照者静息状态下MEG信号之间的统计依赖性（通过计算同步似然性（SL，一种广义同步的度量））。遵循源自图论的方法，我们还通过从SL矩阵计算两个参数，即聚类系数C和特征路径长度L，来分析网络的架构特性。
在患者中发现同步水平改变，且并非局部性的，而是涉及半球内连接。考虑频率子带时效应不同，在长距离连接的高频带中主要是降低，而在局部连接的较慢频段中增加。此外，图分析揭示了正常“小世界”网络架构的变化以及同步水平的变化，根据所研究的频率子带存在一些差异。
脑肿瘤会改变大脑的功能连接和“网络”架构。这些改变并非局部性的，并且考虑频率子带时效应不同。
这些神经生理学变化可能导致脑肿瘤患者出现认知改变。
