McCarthy Rosaleen A, James-Galton Merle, Plant Gordon T
University of Cambridge, Department of Experimental Psychology, Downing Street, Cambridge CB2 3EB, UK.
Neuropsychologia. 2006;44(8):1269-81. doi: 10.1016/j.neuropsychologia.2006.01.036. Epub 2006 Apr 3.
Patients with homonymous hemianopia may report the completion of forms that overlap the vertical meridian of their field defects. While previous investigations of "hemianopic completion" have variously attributed to the disorder to inattention, residual vision or unstable fixation, we believe that our investigation has controlled for such potentially confounding factors. We report patient P.O.V. who experienced hemianopic completion in everyday life following a surgical lesion of his left occipital lobe. He showed normal spatial attention and normal spatial orienting: hemianopic completion can therefore occur in the absence of inattention. His completion was retinotopic and affected partial as well as complete forms: his hemianopic completion cannot be attributed to residual visual input or poor fixation. P.O.V.'s completion was also systematically affected by varying stimulus contrast and pattern masking. We argue that while other explanations may be appropriate for different cases, P.O.V.'s hemianopic completion reflects normal "constructive" visual processes and can be attributed to the unconstrained operation of visual routines that are normally involved in the perception of partially occluded forms. As such, this disorder has the potential to shed light on some of the most basic aspects of visual perception.
患有同侧偏盲的患者可能会报告完成那些与他们视野缺损垂直子午线重叠的表格。虽然之前对“偏盲性补全”的研究将这种病症归因于注意力不集中、残余视力或不稳定注视等多种原因，但我们认为我们的研究已经控制了这些潜在的混杂因素。我们报告了患者P.O.V.，他在左侧枕叶手术损伤后在日常生活中经历了偏盲性补全。他表现出正常的空间注意力和正常的空间定向：因此，偏盲性补全可以在没有注意力不集中的情况下发生。他的补全是视网膜拓扑性的，影响部分和完整的图形：他的偏盲性补全不能归因于残余视觉输入或注视不良。P.O.V.的补全也受到不同刺激对比度和图案掩蔽的系统性影响。我们认为，虽然其他解释可能适用于不同的病例，但P.O.V.的偏盲性补全反映了正常的“建构性”视觉过程，并且可以归因于通常参与感知部分遮挡图形的视觉程序的无约束操作。因此，这种病症有可能揭示视觉感知的一些最基本方面。
