Blindsight and visual awareness
Blindsight and visual awareness
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DOI：
10.1006/ccog.1998.0358
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发表时间：
1998-09-01
影响因子：
2.4
通讯作者：
Cowey, A
中科院分区：
文献类型：
--
作者：
Azzopardi, P;Cowey, A
一些纹状皮层受损的患者有盲视——当使用强制选择程序时，他们在临床上的盲视野缺陷中能够区分看不见的刺激。盲视意味着视觉表现和视觉意识之间的严重分离，但信号检测理论表明，它可能与接近意识视觉下限的正常受试者的行为难以区分，在那里，在临床和强迫选择测试中使用不同的反应标准可能导致分离。我们测试了后一种可能性与半视受试者在是-否和强制选择检测静态和移动目标。他的反应标准在“是-否”和“强迫选择”反应之间存在显著差异，这种差异足以产生一种盲目性的分离，这种分离与偏见敏感的表现衡量方法类似。当独立测量偏差时，他对静态目标的敏感性在强迫选择中比在是-否任务中更大（与正常对照对象不同），但他对移动目标的敏感性没有差异。因此，反应标准的差异可以解释是-否和运动的强迫选择检测之间的分离，但不能解释静态模式。研究结果解释了为什么盲视患者明显更容易“意识到”移动的刺激，而不是静态的刺激。然而，他们也暗示盲视不同于正常的阈值附近的视觉，盲视中的模式和运动检测可能依赖于是-否和强迫选择测试中的不同神经机制。(C) 1998学术出版社。
Some patients with damaged striate cortex have blindsight-the ability to discriminate unseen stimuli in their clinically blind visual field defects when forced-choice procedures are used. Blindsight implies a sharp dissociation between visual performance and visual awareness, but signal detection theory indicates that it might be indistinguishable from the behavior of normal subjects near the lower limit of conscious vision, where the dissociations could arise trivially from using different response criteria during clinical and forced-choice tests. We tested the latter possibility with a hemianopic subject during yes-no and forced-choice detection of static and moving targets. His response criterion differed significantly between yes-no and forced-choice responding, and the difference was sufficient to produce a blindsight-like dissociation with bias-sensitive measures of performance. When measured independently of bias, his sensitivity to static targets was greater in the forced-choice than in the yes-no task (unlike normal control subjects), but his sensitivity to moving targets did not differ. Differences in response criterion could therefore account for dissociations between yes-no and forced-choice detection of motion, but not of static pattern. The results explain why patients with blindsight are apparently more often ''aware'' of moving stimuli than of static stimuli. However, they also imply that blindsight is unlike normal vision near threshold, and that pattern- and motion-detection in blindsight may depend on different sets of neural mechanisms during yes-no and forced-choice tests. (C) 1998 Academic Press.