Conway J L, Schiller P H
J Neurophysiol. 1983 Dec;50(6):1330-42. doi: 10.1152/jn.1983.50.6.1330.
This study investigated the organization of the dorsal lateral geniculate nucleus (LGN) of the tree shrew (Tupaia glis) using both microelectrode recording and anatomical techniques. The tree shrew LGN contains approximately 100,000 cells, of which 20% are in layers 2 and 6. These two layers receive input from the ipsilateral eye. The topography of the tree shrew LGN was delineated by taking systematic penetrations through the structure. Examination of the organization of the LGN laminae showed the following: in layer 1 (the lamina next to the optic tract) a mixture of on-center, off-center and on-off center cells was found; the majority of these cells responded transiently to visual stimuli and they had slightly longer conduction latencies than did cells in the other laminae. On-center and off-center cells in laminae 2-6 were sharply segregated: layers 2, 3, and 4 contained off-center cells and layers 5 and 6 contained on-center cells. Most of the cells in laminae 2-6 responded in a sustained manner to visual stimuli. These results suggest that one function of the LGN lamina is to group cells into various classes. Such grouping has now been shown to occur partially or completely for 1) eye of origin, 2) cell types characterized as on-center and off-center, and 3) cell types characterized as producing transient and sustained responses. The nature and degree of laminar specificity, however, varies considerably from species to species.
本研究采用微电极记录和解剖学技术，对树鼩（Tupaia glis）背外侧膝状核（LGN）的组织结构进行了研究。树鼩的LGN包含约100,000个细胞，其中20%位于第2层和第6层。这两层接收来自同侧眼睛的输入。通过对该结构进行系统穿刺，描绘出了树鼩LGN的地形图。对LGN各层组织结构的检查结果如下：在第1层（紧邻视束的层）发现了中心兴奋、中心抑制和中心-周边型细胞的混合；这些细胞中的大多数对视觉刺激有短暂反应，并且它们的传导潜伏期比其他层的细胞略长。第2 - 6层中的中心兴奋细胞和中心抑制细胞被明显分隔开：第2、3和4层包含中心抑制细胞，第5和6层包含中心兴奋细胞。第2 - 6层中的大多数细胞对视觉刺激有持续反应。这些结果表明，LGN层的一个功能是将细胞分为不同类别。现已证明，这种分类在以下方面部分或完全存在：1）起源眼，2）以中心兴奋和中心抑制为特征的细胞类型，以及3）以产生短暂和持续反应为特征的细胞类型。然而，层特异性的性质和程度在不同物种之间有很大差异。
