Department of Ophthalmology, University of Washington, Seattle, WA 98195, USA; Vision Science Center, University of Washington, Seattle, WA 98195, USA.
Department of Ophthalmology, University of Washington, Seattle, WA 98195, USA; Vision Science Center, University of Washington, Seattle, WA 98195, USA; Graduate Program in Neuroscience, University of Washington, Seattle, WA 98195, USA.
Neuron. 2018 Mar 21;97(6):1327-1340.e4. doi: 10.1016/j.neuron.2018.02.006. Epub 2018 Mar 1.
Considerable theoretical and experimental effort has been dedicated to understanding how neural circuits detect visual motion. In primates, much is known about the cortical circuits that contribute to motion processing, but the role of the retina in this fundamental neural computation is poorly understood. Here, we used a combination of extracellular and whole-cell recording to test for motion sensitivity in the two main classes of output neurons in the primate retina-midget (parvocellular-projecting) and parasol (magnocellular-projecting) ganglion cells. We report that parasol, but not midget, ganglion cells are motion sensitive. This motion sensitivity is present in synaptic excitation and disinhibition from presynaptic bipolar cells and amacrine cells, respectively. Moreover, electrical coupling between neighboring bipolar cells and the nonlinear nature of synaptic release contribute to the observed motion sensitivity. Our findings indicate that motion computations arise far earlier in the primate visual stream than previously thought.
人们投入了大量的理论和实验努力来理解神经回路如何检测视觉运动。在灵长类动物中，人们对有助于运动处理的皮质回路有了很多了解，但视网膜在这一基本神经计算中的作用却知之甚少。在这里，我们使用细胞外记录和全细胞记录的组合来测试灵长类动物视网膜中的两种主要输出神经元——小细胞（parvocellular-projecting）和伞细胞（magnocellular-projecting）——的运动敏感性。我们报告说，只有伞细胞，而不是小细胞，对运动敏感。这种运动敏感性分别存在于来自双极细胞和无长突细胞的突触前兴奋和去抑制中。此外，相邻双极细胞之间的电耦合和突触释放的非线性性质有助于观察到的运动敏感性。我们的发现表明，运动计算在灵长类动物视觉流中出现的时间远比之前认为的要早。
