Parallel ON and OFF cone bipolar inputs establish spatially coextensive receptive field structure of blue-yellow ganglion cells in primate retina.
Parallel ON and OFF cone bipolar inputs establish spatially coextensive receptive field structure of blue-yellow ganglion cells in primate retina.
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DOI：
10.1523/jneurosci.1218-09.2009
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发表时间：
2009-07-01
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影响因子：
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通讯作者：
Dacey DM
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文献类型：
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作者：
Crook JD;Davenport CM;Peterson BB;Packer OS;Detwiler PB;Dacey DM
在灵长类动物视网膜中，小的双层“蓝黄”反色神经节细胞分别接受来自短波(S)敏感和长(L)和中(M)波长敏感的锥状光感受器的平行on -去极化和off -超极化输入。然而，产生S和LM锥体对立接受野结构的突触通路仍然存在争议。我们在体外猕猴视网膜中发现，在光光水平下，当识别的杆输入被排除在外时，小的双层细胞显示出空间共扩展的接受野，其中s - on输入与lm - off输入在空间、时间和颜色上保持平衡。用mGluR6受体激动剂L-AP-4阻断ON通路，可消除SON反应，但保留LM-OFF反应。分离的LM成分显示出中心-环绕的感受野结构，与OFF-center， ON-surround的“弥漫性”锥形双极细胞的输入一致。用HEPES增加视网膜缓冲能力会减弱LM-ON环绕成分，这与双极环绕的非gaba能外视网膜反馈机制一致。GABAa/c受体拮抗剂微虫毒素和甘氨酸受体拮抗剂士的宁不影响色平衡或基本的共扩展感受野结构，提示LM-OFF场不是由视网膜内抑制途径产生的。我们的结论是，对立的S-ON和LM-OFF反应源自S-ON和LM-OFF锥形双极细胞的兴奋性感受野中心，并且这些平行双极输入的LM-OFF和on -环绕在很大程度上抵消了，这解释了蓝- on神经节细胞的小而空间上共扩展但频谱上拮抗的感受野结构。
In the primate retina the small bistratified, ‘blue-yellow’ color-opponent ganglion cell receives parallel ON-depolarizing and OFF-hyperpolarizing inputs from short (S) wavelength sensitive and combined long (L) and middle (M) wavelength sensitive cone photoreceptors respectively. However the synaptic pathways that create S vs LM cone-opponent receptive field structure remain controversial. Here we show in the macaque monkey retina in vitro that at photopic light levels, when an identified rod input is excluded, the small bistratified cell displays a spatially coextensive receptive field in which the S-ON-input is in spatial, temporal and chromatic balance with the LM-OFF-input. ON pathway block with L-AP-4, the mGluR6 receptor agonist, abolished the SON response but spared the LM-OFF response. The isolated LM component showed a center-surround receptive field structure consistent with an input from OFF-center, ON-surround ‘diffuse’ cone bipolar cells. Increasing retinal buffering capacity with HEPES attenuated the LM-ON surround component, consistent with a non-GABAergic outer retina feedback mechanism for the bipolar surround. The GABAa/c receptor antagonist picrotoxin and the glycine receptor antagonist strychnine did not affect chromatic balance or the basic coextensive receptive field structure suggesting that the LM-OFF field is not generated by an inner retinal inhibitory pathway. We conclude that the opponent S-ON and LM-OFF responses originate from the excitatory receptive field centers of S-ON and LM-OFF cone bipolar cells and that the LM-OFF- and ON-surrounds of these parallel bipolar inputs largely cancel, explaining the small, spatially coextensive but spectrally antagonistic receptive field structure of the blue-ON ganglion cell.