In the visual system, retinal axons convey visual information from the outside world to dozens of distinct retinorecipient brain regions and organize that information at several levels, including either at the level of retinal afferents, cytoarchitecture of intrinsic retinorecipient neurons, or a combination of the two. Two major retinorecipient nuclei which are densely innervated by retinal axons are the dorsal lateral geniculate nucleus, which is important for classical image-forming vision, and ventral LGN (vLGN), which is associated with non-image-forming vision. The neurochemistry, cytoarchitecture, and retinothalamic connectivity in vLGN remain unresolved, raising fundamental questions of how it receives and processes visual information. To shed light on these important questions, used in situ hybridization, immunohistochemistry, and genetic reporter lines to identify and characterize novel neuronal cell types in mouse vLGN. Not only were a high percentage of these cells GABAergic, we discovered transcriptomically distinct GABAergic cell types reside in the two major laminae of vLGN, the retinorecipient, external vLGN (vLGNe) and the non-retinorecipient, internal vLGN (vLGNi). Furthermore, within vLGNe, we identified transcriptionally distinct subtypes of GABAergic cells that are distributed into four adjacent sublaminae. Using trans-synaptic viral tracing and in vitro electrophysiology, we found cells in each these vLGNe sublaminae receive monosynaptic inputs from retina. These results not only identify novel subtypes of GABAergic cells in vLGN, they suggest the subtype-specific laminar distribution of retinorecipient cells in vLGNe may be important for receiving, processing, and transmitting light-derived signals in parallel channels of the subcortical visual system.

中文翻译：

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不同的 GABA 能神经元在腹外侧膝状体核中组织成亚型特异性的亚型

在视觉系统中，视网膜轴突将来自外部世界的视觉信息传送到数十个不同的视网膜受体大脑区域，并在多个层次组织这些信息，包括视网膜传入神经元、内在视网膜受体神经元的细胞结构或两者的组合. 由视网膜轴突密集支配的两个主要视网膜受体核是背外侧膝状体核，这对经典成像视觉很重要，腹侧 LGN (vLGN) 与非成像视觉相关。vLGN 中的神经化学、细胞结构和视网膜丘脑连接仍未解决，提出了它如何接收和处理视觉信息的基本问题。为了阐明这些重要问题，使用原位杂交、免疫组织化学、和遗传报告系来鉴定和表征小鼠 vLGN 中的新型神经元细胞类型。不仅这些细胞中 GABA 能的比例很高，我们还发现转录组学上不同的 GABA 细胞类型存在于 vLGN 的两个主要薄层中，即视网膜受体的外部 vLGN (vLGNe) 和非视网膜受体的内部 vLGN (vLGN)。此外，在 vLGNe 中，我们鉴定了分布在四个相邻亚层中的 GABA 能细胞的转录不同亚型。使用跨突触病毒追踪和体外电生理学，我们发现每个 vLGNe 亚层中的细胞都接收来自视网膜的单突触输入。这些结果不仅确定了 vLGN 中 GABA 能细胞的新亚型，而且表明 vLGNe 中视网膜受体细胞的亚型特异性层状分布可能对接受、