Boundary completion is automatic and dissociable from shape discrimination
Boundary completion is automatic and dissociable from shape discrimination
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DOI：
10.1523/jneurosci.3225-06.2006
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发表时间：
2006-11-15
影响因子：
5.3
通讯作者：
Foxe, John J.
中科院分区：
文献类型：
--
作者：
Murray, Micah M.;Imber, Michelle L.;Foxe, John J.
正常的视觉感知通过感知填充过程容易地克服次优或劣化的观看条件，增强物体识别和辨别能力。本研究使用视觉诱发电位（VEP）记录结合电神经成像分析，以确定健康人在执行所谓的“瘦/胖”辨别任务（Ringach和Shapley，1996）时，刺激产生虚幻轮廓的边界完成和形状辨别过程的时空脑动力学。首先，结果表明，边界完成过程发生独立的主题的准确性的歧视任务。VEP对存在与不存在错觉轮廓的调制[IC效应（Murray等人，2002）]在124-186 ms刺激后期间，无论任务表现是否正确，在反应幅度和头皮地形方面都是不可区分的。这表明，在这个歧视任务的失败主要不是失败的边界完成的后果。第二，瘦/胖形状辨别过程的电生理学相关性在时间上与边界完成的电生理学相关性是分离的，边界完成发生在处理的实质上较晚的阶段（类似于330 - 406 ms）期间。早期IC效应不受感知轮廓是否产生瘦或胖的形状。相比之下，晚些时候的VEP调制根据感知的形状，只有在刺激产生虚幻的轮廓的情况下，但不为控制刺激的性能是在接近的机会水平。总的来说，这些数据提供了一个多阶段模型的对象处理退化的观看条件下的进一步支持。
Normal visual perception readily overcomes suboptimal or degraded viewing conditions through perceptual filling-in processes, enhancing object recognition and discrimination abilities. This study used visual evoked potential (VEP) recordings in conjunction with electrical neuroimaging analyses to determine the spatiotemporal brain dynamics of boundary completion and shape discrimination processes in healthy humans performing the so-called "thin/fat" discrimination task (Ringach and Shapley, 1996) with stimuli producing illusory contours. First, results suggest that boundary completion processes occur independent of subjects' accuracy on the discrimination task. Modulation of the VEP to the presence versus absence of illusory contours [the IC effect (Murray et al., 2002)] was indistinguishable in terms of response magnitude and scalp topography over the 124-186 ms poststimulus period, regardless of whether task performance was correct. This suggests that failure on this discrimination task is not primarily a consequence of failed boundary completion. Second, the electrophysiological correlates of thin/fat shape discrimination processes are temporally dissociable from those of boundary completion, occurring during a substantially later phase of processing (similar to 330 - 406 ms). The earlier IC effect was unaffected by whether the perceived contour produced a thin or fat shape. In contrast, later time periods of the VEP modulated according to perceived shape only in the case of stimuli producing illusory contours, but not for control stimuli for which performance was at near-chance levels. Collectively, these data provide further support for a multistage model of object processing under degraded viewing conditions.