Brecelj J, Kakigi R, Koyama S, Hoshiyama M
Department of Integrative Physiology, National Institute for Physiological Sciences, Myodaiji, Okazaki, Japan.
Brain Topogr. 1998 Spring;10(3):227-37.
Visual evoked magnetic field (VEF) and visual evoked potentials (VEP) in response to pattern reversal left half-field central (0-2 degrees, 0-5 degrees) and to left half-field peripheral stimulation (2-15 degrees, 5-15 degrees) were simultaneously recorded in 10 normal subjects. The aim was to localize the origin of the largest wave around 100 ms. By comparing the magnetic evoked 100m wave and electric evoked P100 wave, we found that the response to the small central field (0-2 degrees) stimulation was clearly evident in the VEP and not in the VEF, while the response to the peripheral field (2-15 degrees, 5-15 degrees) stimulation was clearly present in both the VEP and VEF. Our findings show that in contrast to the already recognized predominantly macular origin of VEP activity, VEF activity has a peripheral rather than macular prevalence. Our VEF findings are related to the retinotopic organization of the visual cortex; the 100m dipole to the central field (0-5 degrees) was localized more (1.04 +/- 0.84 cm) posterior than was the 100m dipole to peripheral stimulation (5-15 degrees). The localization of 100m dipoles superimposed on magnetic resonance images (MRI) to central stimuli showed interindividual variations that were in agreement with the known variability of the central field representation in the striate cortex: on the convexity of the occipital pole, in the outer surface of the occipital lobe, and around the calcarine fissure of the right hemisphere. In contrast, following peripheral stimulation, the 100m dipole was located along the medial surface of the hemisphere or in the calcarine fissure. Our results suggest that the main origin of the largest wave around l00ms in response to pattern reversal stimuli is in the striate cortex.
对10名正常受试者同时记录了视觉诱发电场（VEF）和视觉诱发电位（VEP），这些反应是针对模式反转左半视野中央（0 - 2度，0 - 5度）以及左半视野周边刺激（2 - 15度，5 - 15度）的。目的是确定大约100毫秒时最大波的起源。通过比较磁诱发的100m波和电诱发的P100波，我们发现对小中央视野（0 - 2度）刺激的反应在VEP中明显而在VEF中不明显，而对周边视野（2 - 15度，5 - 15度）刺激的反应在VEP和VEF中都明显存在。我们的研究结果表明，与已认识到的VEP活动主要起源于黄斑区不同，VEF活动更普遍地起源于周边而非黄斑区。我们关于VEF的研究结果与视觉皮层的视网膜拓扑组织有关；中央视野（0 - 5度）的100m偶极比周边刺激（5 - 15度）的100m偶极定位更靠后（1.04 ± 0.84厘米）。叠加在磁共振图像（MRI）上的中央刺激的100m偶极定位显示个体间存在差异，这与纹状皮层中中央视野表征的已知变异性一致：位于枕极凸面、枕叶外表面以及右半球距状裂周围。相比之下，周边刺激后，100m偶极位于半球内表面或距状裂中。我们的结果表明，模式反转刺激下大约100毫秒时最大波的主要起源在纹状皮层。
