Ossenblok P, Spekreijse H
Netherlands Ophthalmic Research Institute, Amsterdam.
Electroencephalogr Clin Neurophysiol. 1991 May-Jun;80(3):181-93. doi: 10.1016/0168-5597(91)90120-m.
The cortical origin of the pattern onset EP has been investigated over a time window which covers the entire positive-negative-positive complex of the pattern onset EP. On the basis of a dipole source localization approach, the position, orientation and strength of the underlying sources of the pattern onset EP were estimated. For large check stimuli, chosen to have a weak edge specific component in the response, still two components are needed to account for the variance of the responses. Each component corresponds to a single dipole source, and both originate in the extrastriate cortex. These components dominate, respectively, the initial and the late positive peaks of the pattern onset EP. The equivalent dipole sources of the two components show different behaviors with respect to the position of the stimulus in the visual field. The topography and behavior of the equivalent dipole source underlying the early positive component suggest an origin in area 18. The invariance with stimulus location of the dipole source underlying the late positive component suggests an origin beyond area 18. The different topographies of the components also account for the differences in surface distribution of the pattern onset EP to large check stimulation of the upper and lower sectors of the visual field.
在一个覆盖图形起始诱发电位整个正负正复合体的时间窗口内，对图形起始诱发电位的皮质起源进行了研究。基于偶极子源定位方法，估计了图形起始诱发电位潜在源的位置、方向和强度。对于大方格刺激（选择使其反应中边缘特异性成分较弱），仍需要两个成分来解释反应的方差。每个成分对应一个单一的偶极子源，且两者均起源于纹外皮质。这些成分分别主导图形起始诱发电位的初始正峰和晚期正峰。这两个成分的等效偶极子源在视野中刺激位置方面表现出不同的行为。早期正成分下方等效偶极子源的地形图和行为表明起源于18区。晚期正成分下方偶极子源对刺激位置的不变性表明起源于18区之外。这些成分不同的地形图也解释了在对视野上下部分进行大方格刺激时，图形起始诱发电位表面分布的差异。
