Intrinsic properties and functional circuitry of the AII amacrine cell.
Intrinsic properties and functional circuitry of the AII amacrine cell.
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DOI：
10.1017/s0952523811000368
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发表时间：
2012-01
影响因子：
1.9
通讯作者：
Singer, Joshua H.
中科院分区：
文献类型：
--
作者：
Demb, Jonathan B.;Singer, Joshua H.
无长突细胞代表了视网膜神经元中最多样化的类别，包括数十种不同的细胞类型。每种类型都表现出独特的形态，并通过其与兴奋性中间神经元（双极细胞），其他无长突细胞和输出神经元（神经节细胞）的子集的突触产生特定的视觉计算。在这里，我们审查的内在和网络特性，在哺乳动物视网膜中最常见的无长突细胞，AII无长突细胞的功能。AII连接视杆和视锥光感受器通路，形成视杆介导（暗视）视觉回路中的重要环节。因此，AII被称为视杆无长突细胞。然而，我们现在了解到，AII功能延伸到视锥细胞介导的（明视）视觉，并且在暗视和明视条件下的AII功能利用相同的潜在电路：AII彼此电耦合，并且电耦合到某些类型的ON视锥双极细胞的终端。然而，信号流的方向随着照明而变化。在明视条件下，AII网络构成交叉抑制途径，其允许ON信号抑制OFF神经节细胞，并有助于某些神经节细胞类型的运动敏感性。我们将讨论如何AII的内在和网络属性的组合占其独特的作用，在视觉处理。
Amacrine cells represent the most diverse class of retinal neuron, comprising dozens of distinct cell types. Each type exhibits a unique morphology and generates specific visual computations through its synapses with a subset of excitatory interneurons (bipolar cells), other amacrine cells, and output neurons (ganglion cells). Here, we review the intrinsic and network properties that underlie the function of the most common amacrine cell in the mammalian retina, the AII amacrine cell. The AII connects rod and cone photoreceptor pathways, forming an essential link in the circuit for rod-mediated (scotopic) vision. As such, the AII has become known as the rod-amacrine cell. We, however, now understand that AII function extends to cone-mediated (photopic) vision, and AII function in scotopic and photopic conditions utilizes the same underlying circuit: AIIs are electrically coupled to each other and to the terminals of some types of ON cone bipolar cells. The direction of signal flow, however, varies with illumination. Under photopic conditions, the AII network constitutes a cross-over inhibition pathway that allows ON signals to inhibit OFF ganglion cells and contributes to motion sensitivity in certain ganglion cell types. We discuss how the AII’s combination of intrinsic and network properties accounts for its unique role in visual processing.