The Cognitive Neurophysiology Laboratory, Nathan S. Kline Institute for Psychiatric Research, Program in Cognitive Neuroscience and Schizophrenia, Orangeburg, NY, USA.
Eur J Neurosci. 2009 Dec;30(11):2224-34. doi: 10.1111/j.1460-9568.2009.06980.x. Epub 2009 Nov 20.
Cueing relevant spatial locations in advance of a visual target results in modulated processing of that target as a consequence of anticipatory attentional deployment, the neural signatures of which remain to be fully elucidated. A set of electrophysiological processes has been established as candidate markers of the invocation and maintenance of attentional bias in humans. These include spatially-selective event-related potential (ERP) components over the lateral parietal (around 200-300 ms post-cue), frontal (300-500 ms) and ventral visual (> 500 ms) cortex, as well as oscillatory amplitude changes in the alpha band (8-14 Hz). Here, we interrogated the roles played by these anticipatory processes in attentional orienting by testing for links with subsequent behavioral performance. We found that both target discriminability (d') and reaction times were significantly predicted on a trial-by-trial basis by lateralization of alpha-band amplitude in the 500 ms preceding the target, with improved speed and accuracy resulting from a greater relative decrease in alpha over the contralateral visual cortex. Reaction time was also predicted by a late posterior contralateral positivity in the broad-band ERP in the same time period, but this did not influence d'. In a further analysis we sought to identify the control signals involved in generating the anticipatory bias, by testing earlier broad-band ERP amplitude for covariation with alpha lateralization. We found that stronger alpha biasing was associated with a greater bilateral frontal positivity at approximately 390 ms but not with differential amplitude across hemispheres in any time period. Thus, during the establishment of an anticipatory spatial bias, while the expected target location is strongly encoded in lateralized activity in parietal and frontal areas, a distinct non-spatial control process seems to regulate the strength of the bias.
在视觉目标之前提示相关的空间位置会导致对该目标的调制处理，这是由于预期注意力的部署，其神经特征仍有待充分阐明。已经确定了一组电生理过程作为人类注意力偏向调用和维持的候选标记。这些包括空间选择性事件相关电位（ERP）成分，超过外侧顶叶（提示后约 200-300ms），额叶（300-500ms）和腹侧视觉（>500ms）皮层，以及α波段（8-14Hz）的振荡幅度变化。在这里，我们通过测试与后续行为表现的联系来探究这些预期过程在注意力定向中的作用。我们发现，在目标前 500ms 内的α带振幅的偏侧化显著预测了目标辨别力（d'）和反应时间，并且由于对侧视觉皮层上的α相对减少，速度和准确性得到了提高。反应时间也可以通过同一时期宽带 ERP 中的后期对侧正性来预测，但这不会影响 d'。在进一步的分析中，我们通过测试宽带 ERP 振幅与α偏侧化的早期变异性，试图确定产生预期偏差的控制信号。我们发现，更强的α偏向与大约 390ms 时双侧额部正性更强相关，但在任何时间段内都不会与半球间的差异幅度相关。因此，在建立预期的空间偏向时，虽然预期的目标位置在顶叶和额叶区域的偏侧化活动中被强烈编码，但似乎存在一个独特的非空间控制过程来调节偏向的强度。
