Lütkenhöner B, Menninghaus E, Steinsträter O, Wienbruch C, Gissler H M, Elbert T
Institute for Experimental Audiology, Münster, Germany.
Brain Topogr. 1995 Summer;7(4):291-9. doi: 10.1007/BF01195255.
Sources of the somatosensory evoked fields (SEF) for one subject were estimated using constraints from the magnetic resonance images (MRI) of the same subject. A realistic volume conductor model was shaped corresponding to the inside of the skull. Sources were restricted to a dipole patch riding on the surface of the cortex, reconstructed from the individual MRI. Such a patch can be considered as a uniformly activated cortical area giving rise to distributed currents which flow perpendicular to the cortical surface. Source locations obtained for the SEF in response to separate stimulations of lower lip, first and fifth digit, and collarbone followed the course of the contralateral central sulcus. The order of the estimated source locations was in agreement with the somatosensory homunculus of Penfield and Rasmussen. Similar results were obtained with the simple model of a current dipole in a homogeneous sphere. In contrast, combining a current dipole model with a realistic volume conductor model was rather problematic as it overestimates the radial dipole component by an order of magnitude.
利用同一受试者的磁共振成像（MRI）的约束条件，估计了一名受试者体感诱发电场（SEF）的来源。构建了一个与颅骨内部相对应的逼真的容积导体模型。源被限制在从个体MRI重建的、位于皮质表面的偶极片上。这样一个偶极片可被视为一个均匀激活的皮质区域，产生垂直于皮质表面流动的分布电流。在分别刺激下唇、食指和小指以及锁骨时获得的SEF源位置，遵循对侧中央沟的走向。估计的源位置顺序与彭菲尔德和拉斯穆森的体感小人图一致。在均匀球体中的电流偶极子简单模型也得到了类似结果。相比之下，将电流偶极子模型与逼真的容积导体模型相结合存在相当大的问题，因为它将径向偶极子分量高估了一个数量级。
