Regulation of spatial selectivity by crossover inhibition.
Regulation of spatial selectivity by crossover inhibition.
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DOI：
10.1523/jneurosci.4964-12.2013
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发表时间：
2013-04-10
期刊：
影响因子：
--
通讯作者：
Rieke F
中科院分区：
文献类型：
--
作者：
Cafaro J;Rieke F
整个神经系统中的信号分叉成平行的兴奋性和抑制性通路，这些通路随后会聚在下游神经元上以控制它们的尖峰输出。会聚的兴奋性和抑制性突触输入可以表现出多种时间关系。一个常见的基序是前馈抑制，其中兴奋性输入的增加（减少）先于抑制性输入的相应增加（减少）。抑制性输入相对于兴奋性输入的延迟源于形成抑制性输入的电路中的额外突触。另一个常见的主题是推拉或“交叉”抑制，其中兴奋性输入的增加（减少）与抑制性输入的减少（增加）一起发生。灵长类动物侏儒神经节细胞主要接受前馈抑制和阳伞细胞主要接受交叉抑制;这种差异提供了一个机会，研究每个基序如何塑造在视觉感知中起关键作用的细胞类型的光反应。对于全场的刺激，前馈抑制缩短和衰减的反应上的侏儒细胞，而交叉抑制，虽然丰富的，有令人惊讶的影响不大的反应上的阳伞细胞。空间结构的刺激，但是，可能会导致兴奋性和抑制性的输入对阳伞细胞一起增加，采用的时间关系非常像前馈抑制。在这种情况下，抑制性输入大大缩短了细胞的尖峰输出。因此，抑制性输入形状的时间刺激选择性的侏儒和阳伞神经节细胞，但其对阳伞细胞的反应的影响强烈依赖于空间结构的光输入。
Signals throughout the nervous system diverge into parallel excitatory and inhibitory pathways that later converge on downstream neurons to control their spike output. Converging excitatory and inhibitory synaptic inputs can exhibit a variety of temporal relationships. A common motif is feedforward inhibition, in which an increase (decrease) in excitatory input precedes a corresponding increase (decrease) in inhibitory input. The delay of inhibitory input relative to excitatory input originates from an extra synapse in the circuit shaping inhibitory input. Another common motif is push-pull or “crossover” inhibition, in which increases (decreases) in excitatory input occur together with decreases (increases) in inhibitory input. Primate On midget ganglion cells receive primarily feedforward inhibition and On parasol cells receive primarily crossover inhibition; this difference provides an opportunity to study how each motif shapes the light responses of cell types that play a key role in visual perception. For full-field stimuli, feedforward inhibition abbreviated and attenuated responses of On midget cells, while crossover inhibition, though plentiful, had surprisingly little impact on the responses of On parasol cells. Spatially structured stimuli, however, could cause excitatory and inhibitory inputs to On parasol cells to increase together, adopting a temporal relation very much like that for feedforward inhibition. In this case, inhibitory inputs substantially abbreviated a cell’s spike output. Thus inhibitory input shapes the temporal stimulus selectivity of both midget and parasol ganglion cells, but its impact on responses of parasol cells depends strongly on the spatial structure of the light inputs.