Institute of Cognitive Neuroscience, University College London, UK.
J Cogn Neurosci. 2011 Mar;23(3):631-44. doi: 10.1162/jocn.2010.21433. Epub 2010 Feb 10.
Edge-assignment determines the perception of relative depth across an edge and the shape of the closer side. Many cues determine edge-assignment, but relatively little is known about the neural mechanisms involved in combining these cues. Here, we manipulated extremal edge and attention cues to bias edge-assignment such that these two cues either cooperated or competed. To index their neural representations, we flickered figure and ground regions at different frequencies and measured the corresponding steady-state visual-evoked potentials (SSVEPs). Figural regions had stronger SSVEP responses than ground regions, independent of whether they were attended or unattended. In addition, competition and cooperation between the two edge-assignment cues significantly affected the temporal dynamics of edge-assignment processes. The figural SSVEP response peaked earlier when the cues causing it cooperated than when they competed, but sustained edge-assignment effects were equivalent for cooperating and competing cues, consistent with a winner-take-all outcome. These results provide physiological evidence that figure-ground organization involves competitive processes that can affect the latency of figural assignment.
边缘分配决定了对边缘对面相对深度的感知和近侧的形状。许多线索决定了边缘分配，但对于涉及组合这些线索的神经机制知之甚少。在这里，我们操纵了极值边缘和注意力线索，以偏向边缘分配，使得这两个线索要么合作，要么竞争。为了对它们的神经表示进行索引，我们以不同的频率闪烁图形和背景区域，并测量相应的稳态视觉诱发电位（SSVEP）。图形区域的 SSVEP 响应比背景区域强，无论它们是否受到关注。此外，两种边缘分配线索之间的竞争和合作显著影响了边缘分配过程的时间动态。当引起它的线索合作时，图形 SSVEP 响应比竞争时更早达到峰值，但合作和竞争线索的持续边缘分配效应是等效的，这与赢家通吃的结果一致。这些结果提供了生理学证据，表明图形-背景组织涉及竞争过程，这些过程可能会影响图形分配的潜伏期。
