PARAMETERS AFFECTING CONSCIOUS VERSUS UNCONSCIOUS VISUAL-DISCRIMINATION WITH DAMAGE TO THE VISUAL-CORTEX (V1)
PARAMETERS AFFECTING CONSCIOUS VERSUS UNCONSCIOUS VISUAL-DISCRIMINATION WITH DAMAGE TO THE VISUAL-CORTEX (V1)
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DOI：
10.1073/pnas.92.13.6122
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发表时间：
1995-06-20
影响因子：
11.1
通讯作者：
SAHRAIE, A
中科院分区：
文献类型：
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作者：
WEISKRANTZ, L;BARBUR, JL;SAHRAIE, A
当受试者的视觉(纹状)皮质(V1)受损时，皮层失明导致对侧半视野，然而，在某些实验条件下，受试者表现出在盲半视野中进行视觉辨别的能力(盲视)，即使他们没有明显的视觉经验，因此，这种能力必须通过平行投射到其他大脑区域来调节。一些受试者对快速移动的刺激或呈现给盲半视野的光通量水平的突然变化有意识的残余视力也是如此，其特征是一种无内容的意识，感觉发生了什么，尽管不是正常的看到，这两种辨别方式之间的关系一直没有被系统地研究过，在同一实验中，我们考察了V1一侧受损受试者对运动刺激的无意识辨别和有意识视觉知觉，结果表明，在没有公认知觉的情况下，被试具有很好的辨别运动方向和定向的能力。对于公认意识的刺激参数的辨别显然遵循与刺激速度、位移和刺激对比度不同的函数关系。由于在两种模式下的表现可以在数量上匹配，研究结果表明，应该可以成像大脑活动，并识别同一受试者在有意识和无意识的情况下执行相同辨别任务时涉及的活跃区域，从而确定是否有任何结构对有意识的感知有独特的贡献。
When the visual (striate) cortex (V1) is damaged in human subjects, cortical blindness results in the contralateral visual half field, Nevertheless, under some experimental conditions, subjects demonstrate a capacity to make visual discriminations in the blind hemifield (blindsight), even though they have no phenomenal experience of seeing, This capacity must, therefore, be mediated by parallel projections to other brain areas, It is also the case that some subjects have conscious residual vision in response to fast moving stimuli or sudden changes in light flux level presented to the blind hemifield, characterized by a contentless kind of awareness, a feeling of something happening, albeit not normal seeing, The relationship between these two modes of discrimination has never been studied systematically, We examine, in the same experiment, both the unconscious discrimination and the conscious visual awareness of moving stimuli in a subject with unilateral damage to V1, The results demonstrate an excellent capacity to discriminate motion direction and orientation in the absence of acknowledged perceptual awareness. Discrimination of the stimulus parameters for acknowledged awareness apparently follows a different functional relationship with respect to stimulus speed, displacement, and stimulus contrast. As performance in the two modes can be quantitatively matched, the findings suggest that it should be possible to image brain activity and to identify the active areas involved in the same subject performing the same discrimination task, both with and without conscious awareness, and hence to determine whether any structures contribute uniquely to conscious perception.