Mastronarde D N, Humphrey A L, Saul A B
Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder.
Vis Neurosci. 1991 Sep;7(3):191-200. doi: 10.1017/s0952523800004028.
We report on the existence of lagged Y (YL) cells in the A laminae of the cat lateral geniculate nucleus (LGN) and on criteria for identifying them using visual and electrical stimulation. Like the lagged X (XL) cells described previously (Mastronarde, 1987a; Humphrey & Weller, 1988a), YL cells responded to a spot stimulus with an initial dip in firing and a delayed latency to discharge after spot onset, and an anomalously prolonged firing after spot offset. However, the cells received excitatory input from retinal Y rather than X afferents, and showed nonlinear spatial summation and other Y-like receptive-field properties. Three YL cells tested for antidromic activation from visual cortex were found to be relay cells, with long conduction latencies similar to those of XL cells. Simultaneous recordings of a YL cell and its retinal Y afferents show striking parallels between lagged X and Y cells in retinogeniculate functional connectivity, and suggest that the YL-cell response profile reflects inhibitory processes occurring within the LGN. The YL cells comprised approximately 5% of Y cells and approximately 1% of all cells in the A laminae. Although infrequently encountered in the LGN, they may be roughly as numerous as Y cells in the retina, and hence could fulfill an important role in vision.
我们报告了猫外侧膝状体核（LGN）A层中滞后Y（YL）细胞的存在，并阐述了使用视觉和电刺激识别它们的标准。与先前描述的滞后X（XL）细胞（Mastronarde，1987a；Humphrey和Weller，1988a）一样，YL细胞对光点刺激的反应是放电先出现一个下降，在光点出现后放电延迟，并且在光点消失后放电异常延长。然而，这些细胞从视网膜Y而非X传入纤维接收兴奋性输入，并表现出非线性空间总和以及其他类似Y细胞的感受野特性。测试的三个从视觉皮层进行逆向激活的YL细胞被发现是中继细胞，其传导潜伏期长，与XL细胞相似。对一个YL细胞及其视网膜Y传入纤维的同步记录显示，在视网膜膝状体功能连接方面，滞后X细胞和Y细胞之间存在显著的相似之处，并表明YL细胞的反应特征反映了LGN内发生的抑制过程。YL细胞约占Y细胞的5%，占A层所有细胞的约1%。虽然在LGN中很少遇到，但它们的数量可能与视网膜中的Y细胞大致相同，因此可能在视觉中发挥重要作用。
