Rodin E A, Rodin M J
Department of Neurology, University of Utah, Salt Lake City 84119, USA.
Brain Topogr. 1995 Spring;7(3):201-8. doi: 10.1007/BF01202379.
Dipole sources were investigated in 22 normal subjects with a variety of strategies available through the BESA program. When all the data were summed one regional source, located near the midline in the basal portions of the occipital lobe, explained 92% of the variance. Two regional sources, initially constrained for symmetry but subsequently freed from constraint placed them also in the occipital regions near the midline and reduced the residual variance to 4%. Pooled data obscure, however, the marked individual differences especially in regard to lateralization. In the individual case the major source was also always in one occipital area but its location, especially the degree of separation from the midline depended upon alpha distribution and the strategy used in the workup of the data. The orientation of the major components of the regional sources was usually in the posterior-anterior direction, fairly parallel to the midline and while the other one pointed to the upper convexity. Because of the considerable variability of the alpha rhythm in given subjects and even within the same individual a model which requires symmetry constraints is not optimal for all instances, even when constraints are lifted thereafter. The study demonstrated the feasibility of distinguishing predominantly mesial sources from those which are bihemipheric with more lateral origins but several different models may have to be used to reach the most realistic conclusions.
通过BESA程序提供的各种策略，对22名正常受试者的偶极子源进行了研究。当所有数据相加时，一个位于枕叶基部中线附近的区域源解释了92%的方差。两个区域源，最初受对称性约束，但随后解除约束，它们也位于中线附近的枕叶区域，将残余方差降低到4%。然而，合并数据掩盖了明显的个体差异，尤其是在偏侧化方面。在个体病例中，主要源也总是位于一个枕叶区域，但其位置，特别是与中线的分离程度取决于α分布和数据处理中使用的策略。区域源主要成分的方向通常是后前方向，相当平行于中线，而另一个指向脑凸面。由于给定受试者甚至同一个体内α节律的显著变异性，即使之后解除约束，需要对称性约束的模型也并非对所有情况都是最优的。该研究证明了区分主要位于内侧的源与那些具有更多外侧起源的双侧半球源的可行性，但可能必须使用几种不同的模型才能得出最现实的结论。
