PACKING GEOMETRY OF HUMAN CONE PHOTORECEPTORS - VARIATION WITH ECCENTRICITY AND EVIDENCE FOR LOCAL ANISOTROPY
PACKING GEOMETRY OF HUMAN CONE PHOTORECEPTORS - VARIATION WITH ECCENTRICITY AND EVIDENCE FOR LOCAL ANISOTROPY
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DOI：
10.1017/s0952523800009639
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发表时间：
1992-08-01
影响因子：
1.9
通讯作者：
SLOAN, KR
中科院分区：
文献类型：
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作者：
CURCIO, CA;SLOAN, KR
人类视锥镶嵌的填充几何结构中的无序被认为有助于减轻空间混叠效应。为了表征锥填充几何形状，我们收集了锥内段的位置在七个位置沿着四个主要和两个斜子午线在成人视网膜。我们生成的统计描述符的基础上分布的距离和角度的Voronoi邻居。压缩抖动模型的参数被拟合到实际的马赛克。使用相关图研究局部各向异性。我们发现：（1）Voronoi近邻间的中值距离随着偏心率的增加而增加，但最小距离不变（6-8 μ m）;（2）在中心凹无杆区的边缘处，锥镶嵌体被压缩和抖动最小;（3）中心凹中心的紊乱类似于Pum等（1990）所描述的;（4）锥体间距在一个方向上比在正交方向上小10-15%;和（5）锥体间距在径向（沿着子午线）上比在切向（沿着等偏心线）上大。几乎恒定的最小距离意味着即使在周边视网膜中也可以对高空间频率进行采样。局部各向异性的锥马赛克的灵长类动物视网膜发育过程中的生长和视网膜神经节细胞的取向偏差进行了讨论。
Disorder in the packing geometry of the human cone mosaic is believed to help alleviate spatial aliasing effects. To characterize cone packing geometry, we gathered positions of cone inner segments at seven locations along four primary and two oblique meridians in an adult human retina. We generated statistical descriptors based on the distribution of distances and angles to Voronoi neighbors. Parameters of a compressed-jittered model were fit to the actual mosaic. Local anisotropies were investigated using correlograms. We find that (1) median distance between Voronoi neighbors increases with eccentricity, but the minimum distance is constant (6-8-mu-m) across peripheral retina; (2) the cone mosaic is least compressed and jittered at the edge of the foveal rod-free zone; (3) disorder in the foveal center resembles that described by Pum et al. (1990); (4) cone spacing is 10-15% less in one direction than in the orthogonal direction; and (5) cone spacing is greater in the radial direction (along meridians) than in the tangential direction (along lines of isoeccentricity). The nearly constant minimum distance implies that high spatial frequencies may be sampled even in peripheral retina. Local anisotropy of the cone mosaic is discussed in relation to the growth of the primate retina during development and to the orientation biases of retinal ganglion cells.