Takeya Ryuji, Kasai Tetsuko
J Vis. 2015;15(13):16. doi: 10.1167/15.13.16.
Attention directed to a part of an object tends to obligatorily spread over all of the spatial regions that belong to the object, which may be critical for rapid object-recognition in cluttered visual scenes. Previous studies have generally used simple rectangles as objects and have shown that attention spreading is reflected by amplitude modulation in the posterior N1 component (150-200 ms poststimulus) of event-related potentials, while other interpretations (i.e., rectangular holes) may arise implicitly in early visual processing stages. By using modified Kanizsa-type stimuli that provided less ambiguity of depth ordering, the present study examined early event-related potential spatial-attention effects for connected and separated objects, both of which were perceived in front of (Experiment 1) and in back of (Experiment 2) the surroundings. Typical P1 (100-140 ms) and N1 (150-220 ms) attention effects of ERP in response to unilateral probes were observed in both experiments. Importantly, the P1 attention effect was decreased for connected objects compared to separated objects only in Experiment 1, and the typical object-based modulations of N1 were not observed in either experiment. These results suggest that spatial attention spreads over a figural object at earlier stages of processing than previously indicated, in three-dimensional visual scenes with multiple depth cues.
将注意力指向物体的一部分往往会必然地扩散到属于该物体的所有空间区域，这对于在杂乱的视觉场景中快速识别物体可能至关重要。以往的研究通常使用简单的矩形作为物体，并表明注意力扩散反映在事件相关电位的后部N1成分（刺激后150 - 200毫秒）的幅度调制上，而其他解释（即矩形孔）可能在早期视觉处理阶段隐性出现。通过使用提供深度排序歧义较少的改良型卡尼兹萨型刺激，本研究考察了连接物体和分离物体的早期事件相关电位空间注意力效应，这两种物体在周围环境的前方（实验1）和后方（实验2）都能被感知到。在两个实验中均观察到了对单侧探测的典型ERP的P1（100 - 140毫秒）和N1（150 - 220毫秒）注意力效应。重要的是，仅在实验1中，与分离物体相比，连接物体的P1注意力效应降低，并且在两个实验中均未观察到典型的基于物体的N1调制。这些结果表明，在具有多个深度线索的三维视觉场景中空间注意力在比先前表明的更早的处理阶段就会扩散到图形物体上。
