Weiskrantz L, Cowey A, Barbur J L
Department of Experimental Psychology, University of Oxford and Applied Vision Research Centre, City University, London, UK.
Brain. 1999 Aug;122 ( Pt 8):1533-8. doi: 10.1093/brain/122.8.1533.
The fact that the pupil constricts differentially to visual stimuli in the absence of changes in light energy makes it a valuable tool for studying normal function as well as residual capacity in hemianopic subjects. When pupillometrically effective stimuli such as equiluminant gratings or coloured patches with an abrupt onset and offset are presented to the 'blind' hemifield, a hemianopic subject with damage largely restricted to striate cortex (V1) sometimes reports being 'aware' of the transient onset/offset, although without 'seeing' as such. The question addressed here is whether the pupil still responds in the condition of blindsight in its strict sense--i.e. discriminative capacity in the absence of acknowledged awareness--when stimuli are deliberately designed to eliminate awareness. This was accomplished by making stimulus onset and offset slow and gradual. The results with a well-studied hemianope, G.Y., demonstrate that there is still a pupillary constriction to isoluminant achromatic gratings and red-coloured stimuli, although reduced in size, in the absence of acknowledged awareness.
在光能量没有变化的情况下，瞳孔对视觉刺激产生不同程度的收缩，这使得瞳孔成为研究正常功能以及偏盲患者残余能力的宝贵工具。当向“盲”半侧视野呈现瞳孔测量有效的刺激，如等亮度光栅或具有突然起止的彩色斑块时，损伤主要局限于纹状皮层（V1）的偏盲患者有时会报告“意识到”短暂的起止，尽管并没有真正“看见”。这里要解决的问题是，当故意设计刺激以消除意识时，在严格意义上的盲视状态下——即在没有公认意识的情况下的辨别能力——瞳孔是否仍会做出反应。这是通过使刺激的起止缓慢而逐渐来实现的。对一位经过充分研究的偏盲患者G.Y.的研究结果表明，在没有公认意识的情况下，对于等亮度的消色差光栅和红色刺激，仍然存在瞳孔收缩，尽管收缩幅度减小了。
