Fu Shimin, Huang Yuxia, Luo Yuejia, Wang Yan, Fedota John, Greenwood Pamela M, Parasuraman Raja
ARCH Laboratory, Department of Psychology, George Mason University, Fairfax, VA 22030-4444, USA.
Neuroimage. 2009 Oct 15;48(1):191-9. doi: 10.1016/j.neuroimage.2009.06.028. Epub 2009 Jun 17.
Perceptual load is known to influence the locus of attentional selection in the brain but through an unknown underlying mechanism. We used event-related potentials (ERPs) to investigate how perceptual load interacts with cue-driven involuntary attention. Perceptual load was manipulated in a line orientation discrimination task in which target location was cued involuntarily by means of peripheral cues. Attentional modulation was observed for P1m (the posterior midline P1 component with peak latency between 108 and 140 ms) with invalid trials eliciting larger P1m than valid trials. This attentional effect on P1m increased as a function of perceptual load, suggesting an early temporal locus for the interaction of perceptual load and involuntary attention. Attentional modulation for the C1 component (peak latency at approximately 80 ms) was also observed, but only for high-load stimuli that were presented intermixed with low-load stimuli. Results suggest that (a) perceptual load affects attentional selection at early processing stages; (b) perceptual load interacts with involuntary attention earlier and with different brain mechanisms relative to voluntary attention; and (c) attentional modulation in the C1 time range is possible under optimal experimental conditions.
已知知觉负载会影响大脑中注意力选择的位点，但具体潜在机制尚不清楚。我们利用事件相关电位（ERP）来研究知觉负载如何与线索驱动的非自愿注意相互作用。在一项线方向辨别任务中对知觉负载进行了操控，在该任务中，目标位置通过外周线索被非自愿地提示。在P1m（峰潜伏期在108至140毫秒之间的后中线P1成分）上观察到了注意调制，无效试验引发的P1m大于有效试验。这种对P1m的注意效应随着知觉负载的增加而增强，表明知觉负载与非自愿注意相互作用存在早期时间位点。对于C1成分（峰潜伏期约为80毫秒）也观察到了注意调制，但仅针对与低负载刺激混合呈现的高负载刺激。结果表明：（a）知觉负载在早期加工阶段影响注意选择；（b）相对于自愿注意，知觉负载与非自愿注意的相互作用更早且涉及不同的脑机制；（c）在最佳实验条件下，C1时间范围内的注意调制是可能的。
