Ault S J, Leventhal A G, Vitek D J, Creel D J
Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City 84132, USA.
J Comp Neurol. 1995 Apr 3;354(2):181-92. doi: 10.1002/cne.903540203.
We compared the central projections of retinal ganglion cells in temporal retina and the cortical representation of visual fields in areas 17 and 18 in cats with various hypopigmentation phenotypes (albino, heterozygous albino, Siamese, and heterozygous Siamese). In all cats studied, we found that the extent of abnormal ipsilateral visual field representation varied widely, and more of the ipsilateral visual field was represented in area 18 than in area 17. The greatest degree of ipsilateral visual field representation was found in albino cats, followed by Siamese, heterozygous albino and heterozygote Siamese cats, respectively. Additionally, in the different groups there was wide variation in the numbers of contralaterally projecting alpha and beta ganglion cells in temporal retina. In all cases, however, contralaterally projecting alpha cells were found to extend further into temporal retina than beta cells. We found that in each cat studied, the maximum extent of the abnormal ipsilateral visual field representation in areas 18 and 17 corresponded to the location of the 50% decussation line (i.e., the point where 50% of the ganglion cells in temporal retina project to the contralateral hemisphere) for alpha and beta cells, respectively, for that cat. Our results suggest that the extent of the abnormal visual field representations in visual cortex of hypopigmented cats reflects the extent of contralaterally projecting retinal ganglion cells in temporal retina.
我们比较了具有不同色素沉着减退表型（白化病、杂合白化病、暹罗猫和杂合暹罗猫）的猫的颞侧视网膜中视网膜神经节细胞的中枢投射以及17区和18区视野的皮质表征。在所有研究的猫中，我们发现同侧视野异常表征的程度差异很大，且18区比17区表征的同侧视野更多。同侧视野表征程度最高的是白化病猫，其次分别是暹罗猫、杂合白化病猫和杂合暹罗猫。此外，不同组中颞侧视网膜中对侧投射的α和β神经节细胞数量差异很大。然而，在所有情况下，发现对侧投射的α细胞比β细胞延伸到颞侧视网膜的范围更远。我们发现，在每只研究的猫中，18区和17区同侧视野异常表征的最大范围分别对应于该猫的α和β细胞的50%交叉线位置（即颞侧视网膜中50%的神经节细胞投射到对侧半球的点）。我们的结果表明，色素沉着减退猫的视觉皮质中异常视野表征的程度反映了颞侧视网膜中对侧投射的视网膜神经节细胞的程度。
