Yerkes National Primate Research Center and Department of Neurology, Emory University School of Medicine, Atlanta, GA 30329, USA.
Proc Natl Acad Sci U S A. 2010 Jan 5;107(1):361-5. doi: 10.1073/pnas.0907658106. Epub 2009 Dec 10.
The visual processing of behaviorally relevant stimuli is enhanced through top-down attentional feedback. One possibility is that feedback targets early visual areas first and the attentional enhancement builds up at progressively later stages of the visual hierarchy. An alternative possibility is that the feedback targets the higher-order areas first and the attentional effects are communicated "backward" to early visual areas. Here, we compared the magnitude and latency of attentional enhancement of firing rates in V1, V2, and V4 in the same animals performing the same task. We found a reverse order of attentional effects, such that attentional enhancement was larger and earlier in V4 and smaller and later in V1, with intermediate results in V2. These results suggest that attentional mechanisms operate via feedback from higher-order areas to lower-order ones.
通过自上而下的注意力反馈，可以增强与行为相关刺激的视觉处理。一种可能是，反馈首先针对早期视觉区域，并且注意力增强在视觉层次结构的后续阶段逐渐建立。另一种可能是，反馈首先针对更高阶的区域，并且注意力效应“向后”传递到早期视觉区域。在这里，我们比较了在执行相同任务的相同动物中，V1、V2 和 V4 的神经元发放率的注意力增强的幅度和潜伏期。我们发现注意力效应的逆序，即注意力增强在 V4 中更大更早，在 V1 中更小更晚，而在 V2 中则处于中间结果。这些结果表明，注意力机制通过来自高阶区域到低阶区域的反馈来运作。
