Retinal ganglion cells (RGCs) are thought to be strictly postsynaptic within the retina. They carry visual signals from the eye to the brain, but do not make chemical synapses onto other retinal neurons. Nevertheless, they form gap junctions with other RGCs and amacrine cells, providing possibilities for RGC signals to feed back into the inner retina. Here we identified such feedback circuitry in the salamander and mouse retinas. First, using biologically inspired circuit models, we found mutual inhibition among RGCs of the same type. We then experimentally determined that this effect is mediated by gap junctions with amacrine cells. Finally, we found that this negative feedback lowers RGC visual response gain without affecting feature selectivity. The principal neurons of the retina therefore participate in a recurrent circuit much as those in other brain areas, not being a mere collector of retinal signals, but are actively involved in visual computations.

中文翻译：

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从视网膜神经节细胞到内部视网膜的反馈

视网膜神经节细胞 (RGC) 被认为是视网膜内严格的突触后细胞。它们将视觉信号从眼睛传送到大脑，但不会在其他视网膜神经元上产生化学突触。然而，它们与其他 RGC 和无长突细胞形成间隙连接，为 RGC 信号反馈到内部视网膜提供了可能性。在这里，我们在蝾螈和小鼠视网膜中发现了这种反馈电路。首先，使用受生物学启发的电路模型，我们发现相同类型的 RGC 之间存在相互抑制。然后我们通过实验确定这种效应是由与无长突细胞的间隙连接介导的。最后，我们发现这种负反馈在不影响特征选择性的情况下降低了 RGC 视觉响应增益。