Rathbun Daniel L, Alitto Henry J, Warland David K, Usrey W Martin
Center for Neuroscience, University of CaliforniaDavis, Davis, CA, USA; Institute for Ophthalmology and Center for Integrative Neuroscience, University of TübingenTübingen, Germany.
Center for Neuroscience, University of CaliforniaDavis, Davis, CA, USA; Department of Neurobiology, Physiology, and Behavior, University of CaliforniaDavis, Davis, CA, USA.
Front Neural Circuits. 2016 Feb 19;10:8. doi: 10.3389/fncir.2016.00008. eCollection 2016.
Neuronal signals conveying luminance contrast play a key role in nearly all aspects of perception, including depth perception, texture discrimination, and motion perception. Although much is known about the retinal mechanisms responsible for encoding contrast information, relatively little is known about the relationship between stimulus contrast and the processing of neuronal signals between visual structures. Here, we describe simultaneous recordings from monosynaptically connected retinal ganglion cells and lateral geniculate nucleus (LGN) neurons in the cat to determine how stimulus contrast affects the communication of visual signals between the two structures. Our results indicate that: (1) LGN neurons typically reach their half-maximal response at lower contrasts than their individual retinal inputs and (2) LGN neurons exhibit greater contrast-dependent phase advance (CDPA) than their retinal inputs. Further analyses suggests that increased sensitivity relies on spatial convergence of multiple retinal inputs, while increased CDPA is achieved, in part, on temporal summation of arriving signals.
传递亮度对比度的神经元信号在几乎所有感知方面都起着关键作用，包括深度感知、纹理辨别和运动感知。尽管我们对负责编码对比度信息的视网膜机制已经了解很多，但对于刺激对比度与视觉结构之间神经元信号处理的关系却知之甚少。在这里，我们描述了对猫的单突触连接视网膜神经节细胞和外侧膝状体核（LGN）神经元的同步记录，以确定刺激对比度如何影响这两个结构之间视觉信号的传递。我们的结果表明：（1）LGN神经元通常在比其单个视网膜输入更低的对比度下达到其最大反应的一半，并且（2）LGN神经元比其视网膜输入表现出更大的对比度依赖性相位提前（CDPA）。进一步的分析表明，灵敏度的提高依赖于多个视网膜输入的空间汇聚，而CDPA的增加部分是通过到达信号的时间总和实现的。
