Baccus Stephen A, Olveczky Bence P, Manu Mihai, Meister Markus
Department of Molecular and Cellular Biology and Center for Brain Science, Harvard University, Cambridge, Massachusetts 02138, USA.
J Neurosci. 2008 Jul 2;28(27):6807-17. doi: 10.1523/JNEUROSCI.4206-07.2008.
Certain ganglion cells in the retina respond sensitively to differential motion between the receptive field center and surround, as produced by an object moving over the background, but are strongly suppressed by global image motion, as produced by the observer's head or eye movements. We investigated the circuit basis for this object motion sensitive (OMS) response by recording intracellularly from all classes of retinal interneurons while simultaneously recording the spiking output of many ganglion cells. Fast, transient bipolar cells respond linearly to motion in the receptive field center. The synaptic output from their terminals is rectified and then pooled by the OMS ganglion cell. A type of polyaxonal amacrine cell is driven by motion in the surround, again via pooling of rectified inputs, but from a different set of bipolar cell terminals. By direct intracellular current injection, we found that these polyaxonal amacrine cells selectively suppress the synaptic input of OMS ganglion cells. A quantitative model of these circuit elements and their interactions explains how an important visual computation is accomplished by retinal neurons and synapses.
视网膜中的某些神经节细胞对感受野中心与周边之间的差异运动敏感，这种差异运动由物体在背景上移动产生，但会被全局图像运动强烈抑制，全局图像运动由观察者的头部或眼睛运动产生。我们通过对所有类型的视网膜中间神经元进行细胞内记录，同时记录许多神经节细胞的脉冲输出，来研究这种物体运动敏感（OMS）反应的电路基础。快速、瞬态双极细胞对感受野中心的运动呈线性反应。它们终末的突触输出经过整流，然后由OMS神经节细胞汇总。一种多轴突无长突细胞由周边的运动驱动，同样是通过整流输入的汇总，但来自不同的双极细胞终末集合。通过直接细胞内电流注入，我们发现这些多轴突无长突细胞选择性地抑制OMS神经节细胞的突触输入。这些电路元件及其相互作用的定量模型解释了视网膜神经元和突触是如何完成一项重要的视觉计算的。
