The computation of directional selectivity in the retina occurs presynaptic to the ganglion cell
The computation of directional selectivity in the retina occurs presynaptic to the ganglion cell
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DOI：
10.1038/84007
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发表时间：
2001-02-01
影响因子：
25
通讯作者：
Borg-Graham, LJ
中科院分区：
文献类型：
--
作者：
Borg-Graham, LJ
方向选择性是指视觉刺激沿一个方向(PREF)移动的反应大于反向(Null)方向移动的反应，其在脊椎动物视网膜中的计算是功能神经生理学中的经典问题。到目前为止，大多数定量实验研究都依赖于细胞外反应来识别方向选择性回路的性质。在这里，我描述了一种细胞内分析，使用的是海龟视网膜定向选择性神经节细胞中突触事件的全细胞贴片记录。这些定量测量使我能够区分各种明确的电路模型类别，这些模型原则上可以解释神经节细胞的方向选择性。我发现神经节细胞的方向选择性是由于兴奋性输入本身具有方向选择性，而在这一计算中隐含的关键分流抑制必须作用于与神经节细胞突触前的细胞。
Directional selectivity is a response that is greater for a visual stimulus moving in one (PREF) direction than for the opposite (NULL) direction, and its computation in the vertebrate retina is a classical issue in functional neurophysiology. To date, most quantitative experimental studies have relied on extracellular responses for identifying properties of the directionally selective circuit. Here I describe an intracellular analysis using whole-cell patch recordings of the synaptic events underlying the spike response in directionally selective ganglion cells of the turtle retina. These quantitative measurements allowed me to distinguish among various explicit classes of circuit models that can, in principle, account for ganglion cell directional selectivity. I found that ganglion cell directional selectivity is due to an excitatory input that itself is directionally selective, and that the crucial shunting inhibition implicated in this computation must act on cells presynaptic to the ganglion cell.