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首页> 外文期刊>The Journal of Physiology >Inner retinal inhibition shapes the receptive field of retinal ganglion cells in primate
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Inner retinal inhibition shapes the receptive field of retinal ganglion cells in primate

机译:视网膜内部抑制作用塑造灵长类动物视网膜神经节细胞的感受野

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摘要

The centre-surround organisation of receptive fields is a feature of most retinal ganglion cells (RGCs) and is critical for spatial discrimination and contrast detection. Although lateral inhibitory processes are known to be important in generating the receptive field surround, the contribution of each of the two synaptic layers in the primate retina remains unclear. Here we studied the spatial organisation of excitatory and inhibitory synaptic inputs onto ON and OFF ganglion cells in the primate retina. All RGCs showed an increase in excitation in response to stimulus of preferred polarity. Inhibition onto RGCs comprised two types of responses to preferred polarity: some RGCs showed an increase in inhibition whilst others showed removal of tonic inhibition. Excitatory inputs were strongly spatially tuned but inhibitory inputs showed more variable organisation: in some neurons they were as strongly tuned as excitation, and in others inhibitory inputs showed no spatial tuning. We targeted one source of inner retinal inhibition by functionally ablating spiking amacrine cells with bath application of tetrodotoxin (TTX). TTX significantly reduced the spatial tuning of excitatory inputs. In addition, TTX reduced inhibition onto those RGCs where a stimulus of preferred polarity increased inhibition. Reconstruction of the spatial tuning properties by somatic injection of excitatory and inhibitory synaptic conductances verified that TTX-mediated inhibition onto bipolar cells increases the strength of the surround in RGC spiking output. These results indicate that in the primate retina inhibitory mechanisms in the inner plexiform layer sharpen the spatial tuning of ganglion cells.
机译:感受野的中心周围组织是大多数视网膜神经节细胞(RGC)的特征,对于空间辨别和对比检测至关重要。尽管已知横向抑制过程在产生感受野周围很重要,但是在灵长类动物视网膜中两个突触层的每一个的作用仍不清楚。在这里,我们研究了灵长类动物视网膜中ON和OFF神经节细胞的兴奋性和抑制性突触输入的空间组织。所有RGC都显示出响应于首选极性刺激而增加的激励。对RGC的抑制包括对优选极性的两种类型的响应:一些RGC显示出抑制作用的增加,而另一些显示出强直抑制作用的消除。兴奋性输入在空间上进行了强烈调整,但抑制性输入显示出更多的可变组织:在某些神经元中,它们与刺激一样强烈地进行调整,而在其他神经元中,抑制性输入则没有空间上的调整。我们通过应用河豚毒素(TTX)的功能性消融刺突的无长突细胞来靶向内部视网膜抑制的一种来源。 TTX大大减少了兴奋性输入的空间调整。另外,TTX对那些优选极性刺激增加抑制作用的RGC降低了抑制作用。通过体细胞注射兴奋性和抑制性突触电导来重建空间调谐特性,证实了TTX介导的对双极细胞的抑制作用会增加RGC突突输出中周围区域的强度。这些结果表明,在灵长类动物视网膜内丛状层中的抑制机制使神经节细胞的空间调谐更加尖锐。

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