School of Medicine, Department of Neurosciences, University of California, San Diego, 9500 Gilman Drive MC 0608, La Jolla, CA 92093-0608, USA.
J Cogn Neurosci. 2011 Apr;23(4):880-95. doi: 10.1162/jocn.2010.21438. Epub 2010 Feb 10.
The temporal sequence of neural processes supporting figure-ground perception was investigated by recording ERPs associated with subjects' perceptions of the face-vase figure. In Experiment 1, subjects continuously reported whether they perceived the face or the vase as the foreground figure by pressing one of two buttons. Each button press triggered a probe flash to the face region, the vase region, or the borders between the two. The N170/vertex positive potential (VPP) component of the ERP elicited by probes to the face region was larger when subjects perceived the faces as figure. Preceding the N170/VPP, two additional components were identified. First, when the borders were probed, ERPs differed in amplitude as early as 110 msec after probe onset depending on subjects' figure-ground perceptions. Second, when the face or vase regions were probed, ERPs were more positive (at ∼ 150-200 msec) when that region was perceived as figure versus background. These components likely reflect an early "border ownership" stage, and a subsequent "figure-ground segregation" stage of processing. To explore the influence of attention on these stages of processing, two additional experiments were conducted. In Experiment 2, subjects selectively attended to the face or vase region, and the same early ERP components were again produced. In Experiment 3, subjects performed an identical selective attention task, but on a display lacking distinctive figure-ground borders, and neither of the early components were produced. Results from these experiments suggest sequential stages of processing underlying figure-ground perception, each which are subject to modifications by selective attention.
通过记录与被试对面孔-花瓶图形感知相关的 ERP，研究了支持图形-背景感知的神经过程的时间顺序。在实验 1 中，被试通过按下两个按钮之一连续报告他们是将面孔还是花瓶视为前景图形。每次按下按钮都会触发面孔区域、花瓶区域或两者之间边界的探针闪光。当被试将面孔视为图形时，探针刺激面孔区域诱发的 ERP 的 N170/顶点正电势（VPP）成分较大。在 N170/VPP 之前，还确定了另外两个成分。首先，当探测边界时，根据被试的图形-背景感知，早在探针起始后 110 毫秒，ERP 的幅度就有所不同。其次，当探测面孔或花瓶区域时，当该区域被视为图形而不是背景时，ERP 更为正（在约 150-200 毫秒）。这些成分可能反映了早期的“边界所有权”阶段，以及随后的“图形-背景分离”处理阶段。为了探讨注意力对这些处理阶段的影响，进行了另外两项实验。在实验 2 中，被试选择性地关注面孔或花瓶区域，再次产生了相同的早期 ERP 成分。在实验 3 中，被试执行了相同的选择性注意任务，但在没有明显图形-背景边界的显示上，都没有产生早期成分。这些实验的结果表明，图形-背景感知的处理有顺序的阶段，每个阶段都受到选择性注意的影响。
