Neuroimaging Department, Cuban Neuroscience Center, Ave 25, Esq 158, #15202, PO Box 6412/6414, Cubanacán, Playa, Havana, Cuba.
Neuroimage. 2010 Feb 1;49(3):2328-39. doi: 10.1016/j.neuroimage.2009.10.030. Epub 2009 Oct 19.
There are few studies on the neuroanatomical determinants of EEG spectral properties that would explain its substantial inter-individual variability in spite of decades of biophysical modeling that predicts this type of relationship. An exception is the negative relation between head size and the spectral position of the alpha peak (P(alpha)) reported in Nunez et al. (1978)-proposed as evidence of the influence of global boundary conditions on slightly damped neocortical waves. Here, we attempt to reexamine this finding by computing the correlations of occipital P(alpha) with various measures of head size and cortical surface area, for 222 subjects from the EEG/MRI database of the Cuban Human Brain Mapping Project. No relation is found (p>0.05). On the other hand, biophysical models also predict that white matter architecture, determining time delays and connectivities, could have an important influence on P(alpha). This led us to explore relations between P(alpha) and DTI fractional anisotropy by means of a multivariate penalized regression. Clusters of voxels with highly significant relations were found. These were positive within the Posterior and Superior Corona Radiata for both hemispheres, supporting biophysical theories predicting that the period of cortico-thalamocortical cycles might be modulating the alpha frequency. Posterior commissural fibers of the Corpus Callosum present the strongest relationships, negative in the inferior part (Splenium), connecting the inferior occipital lobes and positive in the superior part (Isthmus and Tapetum), connecting the superior occipital cortices. We found that white matter architecture rather than neocortical area determines the dynamics of the alpha rhythm.
尽管几十年来生物物理模型一直预测存在这种关系，但关于解释脑电图（EEG）频谱特性个体间差异的神经解剖学决定因素的研究却很少。Nunez 等人（1978 年）报告的头围大小与 alpha 波峰（P(alpha)）的频谱位置之间的负相关是一个例外，这被认为是全局边界条件对轻微阻尼新皮层波的影响的证据。在这里，我们尝试通过计算 222 名来自古巴人脑映射项目 EEG/MRI 数据库的受试者的枕部 P(alpha)与各种头围和皮质表面积测量值之间的相关性，重新检验这一发现。未发现相关性（p>0.05）。另一方面，生物物理模型还预测，决定时间延迟和连通性的白质结构可能对 P(alpha)有重要影响。这促使我们通过多元惩罚回归探索 P(alpha)与弥散张量成像（DTI）各向异性分数之间的关系。发现了具有高度显著关系的体素簇。对于两个半球的后冠状辐射和上冠状辐射，这些关系都是阳性的，这支持了预测皮质-丘脑-皮质循环周期可能调节 alpha 频率的生物物理理论。胼胝体的后连合纤维表现出最强的关系，在下部（压部）为负，连接下枕叶，在上部（峡部和毯部）为正，连接上枕叶皮质。我们发现，白质结构而不是新皮质面积决定了 alpha 节律的动力学。
