The visual evoked potential (VEP) has been shown to reflect the size of the neural population activated by a processing mechanism selective to the temporal – and spatial luminance contrast property of a stimulus. We set out to better understand how the factors determining the neural response associated with these mechanisms. To do so we recorded the VEP from 14 healthy volunteers viewing two series of pattern reversing stimuli with identical temporal—and spatial luminance contrast properties. In one series the size of the elements increased towards the edge of the image, in the other it decreased. In the former element size was congruent with receptive field size across eccentricity, in the later it was incongruent. P100 amplitude to the incongruent series exceeded that obtained to the congruent series. Using electric dipoles due the excitatory neural response we accounted for this using dipole cancellation of electric dipoles of opposite polarity originating in supra‐ and infragranular layers of V1. The phasic neural response in granular lamina of V1 exhibited magnocellular characteristics, the neural response outside of the granular lamina exhibited parvocellular characteristics and was modulated by re‐entrant projections. Using electric current density, we identified areas of the dorsal followed by areas of the ventral stream as the source of the re‐entrant signal modulating infragranular activity. Our work demonstrates that the VEP does not signal reflect the overall level of a neural response but is the result of an interaction between electric dipoles originating from neural responses in different lamina of V1.

中文翻译：

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涉及视网膜分辨力的视觉诱发电位中刺激特性，神经反应及其表现之间关系的研究

视觉诱发电位（VEP）已显示出可通过对刺激的时空和空间亮度对比度特性具有选择性的处理机制激活的神经种群的大小。我们着手更好地了解决定这些机制相关的神经反应的因素。为此，我们记录了14位健康志愿者的VEP，他们观察了两个具有相同时空和空间亮度对比属性的模式反转刺激。在一个系列中，元素的大小朝着图像的边缘增加，而在另一个系列中，元素的大小则减小。在前一种情况下，元素大小与整个偏心率的接受场大小一致，而在后一种情况下，元素大小不一致。P100到不一致序列的振幅超过了获得到一致序列的振幅。由于兴奋性神经反应，使用电偶极子来解决这个问题，我们使用了源自V1上层和颗粒下层的相反极性的电偶极子的偶极子抵消。V1颗粒层中的阶段性神经反应表现出巨细胞特征，颗粒层之外的神经反应表现出细小细胞特征，并受到折返投射的调节。利用电流密度，我们确定了背侧区域，其次是腹侧流区域，这是折返信号调节晶下活动的来源。我们的工作表明，VEP并不反映神经反应的整体水平，而是V1的不同层中源自神经反应的电偶极子之间相互作用的结果。