Amacrine cell contributions to red-green color opponency in central primate retina: a model study.
Amacrine cell contributions to red-green color opponency in central primate retina: a model study.
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无长突细胞对中央灵长类视网膜红绿色对立的贡献：一项模型研究。
DOI：
10.1017/s0952523807070502
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发表时间：
2007
影响因子：
1.9
通讯作者：
Marshak,DW
中科院分区：
文献类型：
--
作者：
Lebedev,DS;Marshak,DW
为了研究无突细胞对红绿对立性的贡献，基于已发表的锥体马赛克，建立了猕猴中央视网膜的线性计算模型。在该模型中，ON和OFF两种类型的无毛细胞都能接收到相邻的所有极性相同的小双极细胞的输入，但OFF型无毛细胞对中心响应由中波长敏感视锥细胞介导的双极细胞有偏向。这种偏倚可能是由于活动依赖的可塑性引起的，因为在OFF通路中存在由短波敏感锥细胞驱动的小型双极细胞。模型小神经节细胞接受相邻两种无突细胞的输入。与生理实验一样，模型神经节细胞对消色差刺激表现出空间对立反应，但它们对视锥隔离刺激的反应就像中心和周围分别由单一视锥驱动一样。在没有无毛细胞输入的情况下，长、中波长敏感锥细胞对模型神经节细胞接受野的中心和周围均有贡献。根据该模型，尽管对单个无毛细胞的输入是非选择性的，但总的无毛细胞输入是红-绿对手的。一个关键的预测是，GABA和甘氨酸使四种类型的中央侏儒神经节细胞中的两种去极化；这可能反映了它们树突中氯化钾共转运体的水平较低。
To investigate the contributions of amacrine cells to red-green opponency, a linear computational model of the central macaque retina was developed based on a published cone mosaic. In the model, amacrine cells of ON and OFF types received input from all neighboring midget bipolar cells of the same polarity, but OFF amacrine cells had a bias toward bipolar cells whose center responses were mediated by middle wavelength sensitive cones. This bias might arise due to activity dependent plasticity because there are midget bipolar cells driven by short wavelength sensitive cones in the OFF pathway. The model midget ganglion cells received inputs from neighboring amacrine cells of both types. As in physiological experiments, the model ganglion cells showed spatially opponent responses to achromatic stimuli, but they responded to cone isolating stimuli as though center and surround were each driven by a single cone type. Without amacrine cell input, long and middle wavelength sensitive cones contributed to both the centers and surrounds of model ganglion cell receptive fields. According to the model, the summed amacrine cell input was red-green opponent even though inputs to individual amacrine cells were unselective. A key prediction is that GABA and glycine depolarize two of the four types of central midget ganglion cells; this may reflect lower levels of the potassium chloride co-transporter in their dendrites.