Levick W R, Thibos L N
Visual Neurosciences Unit, John Curtin School of Medical Research, Australian National University, Canberra.
Vis Neurosci. 1993 May-Jun;10(3):499-509. doi: 10.1017/s0952523800004715.
Receptive fields of ganglion cells have been studied in cats possessing a chronic, arrested lesion of central retinal degeneration. Lesions were characterized by an ophthalmoscopically sharp border separating apparently normal retina from the region of the lesion. Under direct ophthalmoscopic guidance, a succession of recordings was obtained from ganglion cells having cell bodies at various positions relative to the lesion. Cells located more than 1 deg outside the ophthalmoscopic border had normal visual sensitivity as assessed by area-threshold experiments. Inside the lesion cells within 1 deg of the border had reduced sensitivity which often precluded functional classification by the usual visual tests. Ganglion cells located more than 1 deg inside the border of large lesions were blind and some had abnormal patterns of maintained discharge of action potentials. Nevertheless, the antidromic latencies of these blind cells fell into the familiar conduction groups (T1/T2/T3). Receptive-field maps of cells near the border of the lesion often appeared truncated, with the missing portion of the field covered by the lesion. These observations were consistent with the abnormal form of area-threshold curves. Although the responsiveness of cells near the lesion was abnormally low for grating stimuli, cutoff spatial frequency and orientation bias of these cells were within normal limits.
在患有慢性、静止性视网膜中央变性损伤的猫身上，对神经节细胞的感受野进行了研究。这些损伤的特征是在检眼镜下有一个清晰的边界，将明显正常的视网膜与损伤区域分隔开来。在直接检眼镜的引导下，从相对于损伤处于不同位置的神经节细胞体获得了一系列记录。通过面积阈值实验评估，位于检眼镜边界外超过1度的细胞具有正常的视觉敏感性。在损伤区域内，边界1度范围内的细胞敏感性降低，这常常使得通过常规视觉测试进行功能分类变得不可能。位于大损伤边界内超过1度的神经节细胞是失明的，并且一些细胞具有异常的动作电位持续发放模式。然而，这些失明细胞的逆向潜伏期属于常见的传导组（T1/T2/T3）。损伤边界附近细胞的感受野图常常看起来被截断，感受野缺失的部分被损伤所覆盖。这些观察结果与面积阈值曲线的异常形式一致。尽管对于光栅刺激，损伤附近细胞的反应性异常低，但这些细胞的截止空间频率和方向偏差在正常范围内。
