Department of Neuroscience, University of Geneva, Switzerland; Geneva Neuroscience Center, University of Geneva, Switzerland.
Neurosci Biobehav Rev. 2011 Apr;35(5):1237-53. doi: 10.1016/j.neubiorev.2010.12.011. Epub 2010 Dec 24.
An increasing number of human electroencephalography (EEG) studies examining the earliest component of the visual evoked potential, the so-called C1, have cast doubts on the previously prevalent notion that this component is impermeable to top-down effects. This article reviews the original studies that (i) described the C1, (ii) linked it to primary visual cortex (V1) activity, and (iii) suggested that its electrophysiological characteristics are exclusively determined by low-level stimulus attributes, particularly the spatial position of the stimulus within the visual field. We then describe conflicting evidence from animal studies and human neuroimaging experiments and provide an overview of recent EEG and magnetoencephalography (MEG) work showing that initial V1 activity in humans may be strongly modulated by higher-level cognitive factors. Finally, we formulate a theoretical framework for understanding top-down effects on early visual processing in terms of predictive coding.
越来越多的人类脑电图（EEG）研究检查了视觉诱发电位的最早成分，即所谓的 C1，这使得人们对先前普遍存在的观点产生了怀疑，即该成分不受自上而下的影响。本文回顾了最初的研究，这些研究(i)描述了 C1，(ii)将其与初级视觉皮层（V1）活动联系起来，以及(iii)表明其电生理特征完全由低级刺激属性决定，特别是刺激在视野内的空间位置。然后，我们描述了来自动物研究和人类神经影像学实验的矛盾证据，并提供了最近的 EEG 和脑磁图（MEG）研究的概述，这些研究表明人类初始 V1 活动可能受到高级认知因素的强烈调制。最后，我们根据预测编码的理论框架，提出了一个理解早期视觉处理中自上而下效应的理论框架。
