Mechanisms and circuitry underlying directional selectivity in the retina
Mechanisms and circuitry underlying directional selectivity in the retina
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DOI：
10.1038/nature01179
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发表时间：
2002-11-28
期刊：
影响因子：
64.8
通讯作者：
Werblin, FS
中科院分区：
文献类型：
--
作者：
Fried, SI;Münch, TA;Werblin, FS
在视网膜中，定向选择性神经节细胞对其首选方向的运动有强烈的尖峰反应，但对相反方向或零方向(1，2)的运动反应很小。这种计算背后的机制和电路仍然存在争议。在这里，我们通过分离定向选择性细胞的兴奋性和抑制性输入，并测量这些细胞与突触前神经元之间的直接联系，表明突触前中间神经元--星爆无长突细胞--对定向选择性细胞具有直接抑制作用。恒星爆发细胞的突起不对称地连接到方向选择性的细胞：那些指向零方向的细胞提供抑制；那些指向首选方向的细胞不会。恒星爆发细胞在刺激向零方向移动之前，横向地投射抑制。此外，恒星暴增抑制本身在方向上是选择性的：它对零方向上的运动更强。通过作用于突触前对定向选择细胞的抑制信号，减少了对零方向运动的兴奋。这些成分的相互作用减少了零方向上的激发和增强了抑制，从而确保了稳健的方向选择性。
In the retina, directionally selective ganglion cells respond with robust spiking to movement in their preferred direction, but show minimal response to movement in the opposite, or null, direction(1,2). The mechanisms and circuitry underlying this computation have remained controversial(3). Here we show, by isolating the excitatory and inhibitory inputs to directionally selective cells and measuring direct connections between these cells and presynaptic neurons, that a presynaptic interneuron, the starburst amacrine cell, delivers direct inhibition to directionally selective cells. The processes of starburst cells are connected asymmetrically to directionally selective cells: those pointing in the null direction deliver inhibition; those pointing in the preferred direction do not. Starburst cells project inhibition laterally ahead of a stimulus moving in the null direction. In addition, starburst inhibition is itself directionally selective: it is stronger for movement in the null direction. Excitation in response to null direction movement is reduced by an inhibitory signal acting at a site that is presynaptic to the directionally selective cell. The interplay of these components generates reduced excitation and enhanced inhibition in the null direction, thereby ensuring robust directional selectivity.