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Plasticity of the neural network in the compound eye of the Ligia exotica, Roux.

Ligia extrica Roux 复眼中神经网络的可塑性。

基本信息

批准号：
14540625
负责人：
HARIYAMA Takahiko
金额：
$ 2.43万
依托单位：
Hamamatsu University School of Medicine
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-14540625/
关键词：
Crustacea visual neuron plasticity compound eye photoreceptor chromophore information molting ラミナ神経ラブドーム

项目摘要

The eye of Ligia exotica is of the apposition type and has open rhabdoms. The facets are hexagonal, and the dioptric apparatus consist of a flat cornea and a spherical crystalline cone placed in the canter of two large cone cells. Each ommatidium has seven regular retinula cells and one eccentric cell ; basement membrane forms the proximal boundary of the retina. With increases in body size from 0.6 cm to almost 4.0 cm (or some are more), facet numbers and ommatidial diameters increased from 800 to 1500 and 35 μm to 100 μm, respectively ; eye length and width grew from 1.2 to 3.2 and 0.9 to 2.5 mm, respectively ; and length of dioptric apparatus and width of retinal layer changed from 70 μm to 180 μm and about 70 μm to 120 μm. Visual angles and interommatidial angles of centrally located ommatidia remained constant at about 30 and 6.9 degrees, respectively. An almost perfect linear relationship was found when eye length was plotted against the product between the square root of the tot … More al number of ommatidia and the ommatuaal diameter. No diference between males and females was observed in any of the relationships.How does the number of the ommatidia increase? We tried to observe the marginal region of the compound eye of L. exotica. In order to characterize the marginal ommatidia from different eye regions, we made a detailed description of their distinct ultrastrtictural features in three different size-classes of Laxotica. On the bases of transverse as well as longitudinal sections we concluded that new ommatidia are added from a crescentic dorso-snterio-ventral edge of the eye and that maturing ommatidia go through a sequence in which originally the nuclei of cone-, pigment-, and retinula cells are arranged in three separate layers. At the beginning of the microvillar development, the organization of the corresponding rhabdomeres is still quite different from that of those rhabdomeres that make up the mature rhabdom. Marginal ommatidia always possess smaller diameters than more centrally located ones and retinal screening pigment granules are most apparent in the retinula cells only after the first micovilli have appeared.In order to know the amount of the visual pigments following the increase of the number of ommatidia, we measured the amount of chromophores using the several different eye size-classes of Ligia by the oxime method. The smaller animals (smaller than 2cm in body size) possessed only 40 pmol, whereas, the larger ones (ca.3.5 cm) possessed 100 pmol in their two sessile eyes.All of the value which we measure showed the increase following the increase of the body size, except the visual angle. Those results suggest that all specimens possess the same visual worlds basically because the larger specimens possess the almost same visual angles compared with the smaller ones. Less

异色立眼为对位型，有开放的纹状体。小平面是六角形的，屈光设备由一个扁平的角膜和一个放置在两个大锥体细胞的小腿上的球形晶体锥体组成。每个小眼有七个规则的视网膜细胞和一个偏心细胞；基底膜形成视网膜的近端边界。随体长从0.6 cm增加到近4.0 cm(或更多)，小孔数和小眼直径分别从80 0~15 0 0和35μm增加到10 0μm，眼长和眼宽分别从1.2~3.2和0.9~2.5 mm增加，屈光装置长度和视网膜层宽度从70μm增加到180μm，约70μm增加到12 0μm，位于中央位置的小眼视野和小眼间角度分别保持在30度和6.9度左右。当眼长与TOT…的平方根之间的乘积作图时，发现了几乎完全的线性关系小眼个数和小眼直径较多。在所有的关系中，没有观察到男女之间的差异。小眼的数量是如何增加的？我们试图观察异色斑潜蝇复眼的边缘区域。为了刻画不同眼区的边缘小眼，我们详细描述了三个不同大小的Laxotica的边缘小眼的超微结构特征。在横切面和纵切面的基础上，我们得出结论：新的小眼是从新月形的眼背-内-腹缘增加的，成熟的小眼经历了最初锥体细胞、色素细胞和视网膜细胞的核排列成三层的顺序。在微绒毛发育的初期，相应的横纹肌的组织结构与组成成熟横纹肌的横纹肌的组织结构仍然有很大的不同。边缘小眼的直径往往小于位于中心的小小眼，只有在第一个小眼球出现后，视网膜遮挡色素颗粒才在视网膜细胞中最为明显。为了了解随着小眼数目的增加，视觉色素的数量，我们用肟法测量了几种不同眼睛大小的Ligia的生色团的数量。体型较小的动物(小于2 cm)的双眼只有40pmoL，而较大的动物(约3.5 cm)的双眼有100pmoL，除视角外，其余测量值均随体型的增大而增大。这些结果表明，所有的样本基本上都拥有相同的视觉世界，因为与较小的样本相比，较大的样本具有几乎相同的视角。较少