Different mechanisms generate maintained activity in ON and OFF retinal ganglion cells
Different mechanisms generate maintained activity in ON and OFF retinal ganglion cells
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DOI：
10.1523/jneurosci.0130-07.2007
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发表时间：
2007-05-30
影响因子：
5.3
通讯作者：
Detwiler, Peter B.
中科院分区：
文献类型：
--
作者：
Margolis, David J.;Detwiler, Peter B.
神经元放电由突触输入或细胞自主的内在起搏活动驱动。通常认为视网膜神经节细胞（RGC）（视网膜的输出细胞）的静息峰电位活动是由突触驱动的，因为视网膜光感受器和二级细胞紧张性地释放神经递质。在这里，我们表明，ON和OFF RGCs通过不同的机制产生维持活动：ON细胞依赖于紧张性兴奋性输入来驱动静息活动，而OFF细胞在没有突触输入的情况下继续放电。除了自发活动，OFF细胞还表现出起搏神经元的其他特性，包括阈下振荡、爆发性放电和反弹性兴奋。因此，突触机制和内在特性的可变权重是这些平行视网膜通路中维持活性的产生差异的基础。
Neuronal discharge is driven by either synaptic input or cell-autonomous intrinsic pacemaker activity. It is commonly assumed that the resting spike activity of retinal ganglion cells (RGCs), the output cells of the retina, is driven synaptically, because retinal photoreceptors and second-order cells tonically release neurotransmitter. Here we show that ON and OFF RGCs generate maintained activity through different mechanisms: ON cells depend on tonic excitatory input to drive resting activity, whereas OFF cells continue to fire in the absence of synaptic input. In addition to spontaneous activity, OFF cells exhibit other properties of pacemaker neurons, including subthreshold oscillations, burst firing, and rebound excitation. Thus, variable weighting of synaptic mechanisms and intrinsic properties underlies differences in the generation of maintained activity in these parallel retinal pathways.