Exploring the retinal connectome
Exploring the retinal connectome
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发表时间：
2011-02
期刊：
影响因子：
2.2
通讯作者：
James R. Anderson;B. Jones;C. Watt;M. V. Shaw;Jia-Hui Yang;D. DeMill;J. S. Lauritzen;Yanhua Lin;K. Rapp;D. Mastronarde;Pavel A. Koshevoy;B. Grimm;T. Tasdizen;R. Whitaker;R. Marc
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作者：
James R. Anderson;B. Jones;C. Watt;M. V. Shaw;Jia-Hui Yang;D. DeMill;J. S. Lauritzen;Yanhua Lin;K. Rapp;D. Mastronarde;Pavel A. Koshevoy;B. Grimm;T. Tasdizen;R. Whitaker;R. Marc
目的连接体是对神经元突触连接的综合描述。我们的目标是产生一个哺乳动物视网膜内丛状层的连接体数据集。本文描述了我们的第一个视网膜连接体，验证了方法，并提供了关键的初步发现。方法：我们获得并组装了一个16.5 TB的连接体数据集RC 1的兔视网膜在102 nm的分辨率，使用自动透射电子显微镜成像，自动镶嵌，和自动体积注册。RC 1代表直径为0.25 mm的组织柱，跨越内核层、内丛状层和神经节细胞层。为了增强超微结构跟踪，我们包括4-氨基丁酸（GABA），谷氨酸，甘氨酸，牛磺酸，谷氨酰胺的分子标记物，和体内活性标记物，1-氨基-4-胍丁烷。这使我们能够区分GABA能和甘氨酸能无长突细胞;识别与甘氨酸能细胞偶联的ON双极细胞;并根据其分子特征和活性区分不同类型的双极细胞、无长突细胞和神经节细胞。我们的多用户导航工具维京海盗对数据集进行了探索和注释。注释被导出到其他应用程序中，以渲染单元格、可视化网络图和查询数据库。结果RC 1的探索表明，2 nm分辨率很容易重现众所周知的连接，并揭示了视网膜组织的几个新特征：（1）AII无长突细胞信号通路比以往报道的更为复杂，有不少于17种不同的信号模式，包括来自OFF双极细胞、宽视野ON锥双极细胞和杆双极细胞的带状突触输入，以及来自视锥通路无长突细胞的大量输入。(2)大多数视锥双极细胞的轴突形成了一个独特的信号整合区室，ON视锥双极细胞轴突突触针对不同的细胞类型。ON和OFF双极细胞都接受轴突否决突触。(3)常规突触的链是非常常见的，具有插入的甘氨酸能-GABA能链和与星状无长突细胞相关的非常长的链。甘氨酸能无长突细胞显然在开-关交叉抑制中发挥重要作用。(4)分子和兴奋映射清楚地隔离超微结构定义的双极细胞群到不同的反应集群。(5)最后，低分辨率的电子或光学成像不能可靠地映射突触连接的过程的几何形状，作为相邻没有突触接触是丰富的视网膜。只有直接可视化的突触和缝隙连接就足够了。结论使用传统的透射电子显微镜进行连接组组装和分析对于网络发现是可行的。我们的调查卷RC 1表明，以前研究的系统，如AII无长突细胞网络涉及更多的网络图案比以前已知的。主要被认为是暗视通路的AII网络清楚地从明视ON和OFF锥双极细胞网络和广泛的明视GABA能无长突细胞输入中获得带状突触输入。此外，双极细胞显示出广泛的输入和输出沿着其轴突，类似于多层非哺乳动物双极细胞。我们的解剖数据强烈支持显着的开-关通道交叉的生理证据，显示交替甘氨酸-GABA路径。长链无长突细胞网络可能来自星爆状无长突细胞之间的同型细胞GABA能突触。对RC 1的深入分析为更完整地描述特定网络提供了机会。
Purpose A connectome is a comprehensive description of synaptic connectivity for a neural domain. Our goal was to produce a connectome data set for the inner plexiform layer of the mammalian retina. This paper describes our first retinal connectome, validates the method, and provides key initial findings. Methods We acquired and assembled a 16.5 terabyte connectome data set RC1 for the rabbit retina at ≈2 nm resolution using automated transmission electron microscope imaging, automated mosaicking, and automated volume registration. RC1 represents a column of tissue 0.25 mm in diameter, spanning the inner nuclear, inner plexiform, and ganglion cell layers. To enhance ultrastructural tracing, we included molecular markers for 4-aminobutyrate (GABA), glutamate, glycine, taurine, glutamine, and the in vivo activity marker, 1-amino-4-guanidobutane. This enabled us to distinguish GABAergic and glycinergic amacrine cells; to identify ON bipolar cells coupled to glycinergic cells; and to discriminate different kinds of bipolar, amacrine, and ganglion cells based on their molecular signatures and activity. The data set was explored and annotated with Viking, our multiuser navigation tool. Annotations were exported to additional applications to render cells, visualize network graphs, and query the database. Results Exploration of RC1 showed that the 2 nm resolution readily recapitulated well known connections and revealed several new features of retinal organization: (1) The well known AII amacrine cell pathway displayed more complexity than previously reported, with no less than 17 distinct signaling modes, including ribbon synapse inputs from OFF bipolar cells, wide-field ON cone bipolar cells and rod bipolar cells, and extensive input from cone-pathway amacrine cells. (2) The axons of most cone bipolar cells formed a distinct signal integration compartment, with ON cone bipolar cell axonal synapses targeting diverse cell types. Both ON and OFF bipolar cells receive axonal veto synapses. (3) Chains of conventional synapses were very common, with intercalated glycinergic-GABAergic chains and very long chains associated with starburst amacrine cells. Glycinergic amacrine cells clearly play a major role in ON-OFF crossover inhibition. (4) Molecular and excitation mapping clearly segregates ultrastructurally defined bipolar cell groups into different response clusters. (5) Finally, low-resolution electron or optical imaging cannot reliably map synaptic connections by process geometry, as adjacency without synaptic contact is abundant in the retina. Only direct visualization of synapses and gap junctions suffices. Conclusions Connectome assembly and analysis using conventional transmission electron microscopy is now practical for network discovery. Our surveys of volume RC1 demonstrate that previously studied systems such as the AII amacrine cell network involve more network motifs than previously known. The AII network, primarily considered a scotopic pathway, clearly derives ribbon synapse input from photopic ON and OFF cone bipolar cell networks and extensive photopic GABAergic amacrine cell inputs. Further, bipolar cells show extensive inputs and outputs along their axons, similar to multistratified nonmammalian bipolar cells. Physiologic evidence of significant ON-OFF channel crossover is strongly supported by our anatomic data, showing alternating glycine-to-GABA paths. Long chains of amacrine cell networks likely arise from homocellular GABAergic synapses between starburst amacrine cells. Deeper analysis of RC1 offers the opportunity for more complete descriptions of specific networks.