State Key Laboratory of Brain and Cognitive Sciences, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.
PLoS One. 2011 May 5;6(5):e19477. doi: 10.1371/journal.pone.0019477.
The ON-OFF direction selective ganglion cells (DSGCs) in the mammalian retina code image motion by responding much more strongly to movement in one direction. They do so by receiving inhibitory inputs selectively from a particular sector of processes of the overlapping starburst amacrine cells, a type of retinal interneuron. The mechanisms of establishment and regulation of this selective connection are unknown. Here, we report that in the rat retina, the morphology, physiology of the ON-OFF DSGCs and the circuitry for coding motion directions develop normally with pharmacological blockade of GABAergic, cholinergic activity and/or action potentials for over two weeks from birth. With recent results demonstrating light independent formation of the retinal DS circuitry, our results strongly suggest the formation of the circuitry, i.e., the connections between the second and third order neurons in the visual system, can be genetically programmed, although emergence of direction selectivity in the visual cortex appears to require visual experience.
哺乳动物视网膜中的 ON-OFF 方向选择性节细胞 (DSGCs) 通过对一个方向的运动做出更强烈的反应来编码图像运动。它们通过从重叠的星爆型无长突细胞的特定扇区选择性接收抑制性输入来实现这一点，星爆型无长突细胞是一种视网膜中间神经元。这种选择性连接的建立和调节的机制尚不清楚。在这里，我们报告在大鼠视网膜中，ON-OFF DSGCs 的形态和生理学以及用于编码运动方向的电路在出生后超过两周的时间内，通过药理学阻断 GABA 能、胆碱能活性和/或动作电位而正常发育。最近的研究结果表明，视网膜 DS 电路的形成不依赖于光，因此我们的研究结果强烈表明，尽管视觉皮层中的方向选择性似乎需要视觉经验，但视觉系统中第二和第三级神经元之间的连接可以通过遗传编程来形成。
