The effect of crowding on orientation-selective adaptation in human early visual cortex
The effect of crowding on orientation-selective adaptation in human early visual cortex
复制标题
拥挤对人类早期视觉皮层方向选择性适应的影响
DOI：
10.1167/9.11.13
复制
发表时间：
2009-01-01
影响因子：
1.8
通讯作者：
Fang, Fang
中科院分区：
文献类型：
--
作者：
Bi, Taiyong;Cai, Peng;Fang, Fang
拥挤是在附近侧翼存在的情况下识别目标的困难。基于心理物理学的发现，许多理论已经被提出来解释多层次的拥挤。然而，对其神经机制知之甚少。在这项研究中，我们结合心理物理学和功能磁共振成像适应技术，寻找拥挤的皮层位点。在心理物理实验中，当被试的注意力被控制时，我们发现，阈值升高后效应（TEAE）不受拥挤的影响，无论适应刺激的对比度水平。在fMRI实验中，V1区的方向选择性fMRI适应也不受拥挤的影响。然而，在V1的下游，我们发现拥挤减弱了V2和V3的适应效应。我们的研究结果表明，拥挤发生在V1之后，并提供了支持拥挤的两阶段模型（D。M. Levi，2008）。
Crowding is the identification difficulty for a target in the presence of nearby flankers. Based on psychophysical findings, many theories have been proposed to explain crowding at multiple levels. However, little is known about its neural mechanism. In this study, we combined psychophysical and fMRI adaptation techniques to search for the cortical locus of crowding. In the psychophysical experiment, when subjects' attention was controlled, we found that the threshold elevation aftereffect (TEAE) was not affected by crowding, regardless of the contrast level of adapting stimulus. In the fMRI experiment, the orientation-selective fMRI adaptation in V1 was not affected by crowding either. However, downstream from V1, we found that crowding weakened the adaptation effect in V2 and V3. Our results demonstrate that crowding occurs beyond V1 and provide one of the first pieces of direct evidence supporting the two-stage model of crowding (D. M. Levi, 2008).