Retinal ganglion cells can rapidly change polarity from Off to On.
Retinal ganglion cells can rapidly change polarity from Off to On.
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DOI：
10.1371/journal.pbio.0050065
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发表时间：
2007-03
期刊：
影响因子：
9.8
通讯作者：
Meister, Markus
中科院分区：
文献类型：
--
作者：
Geffen, Maria Neimark;de Vries, Saskia E J;Meister, Markus
视网膜神经节细胞通常被分类为中心或偏离中心，这取决于它们是否主要通过感受野内的增亮或变暗来兴奋。在这里，我们报告说，蝾螈视网膜中的许多神经节细胞可以从一种反应类型切换到另一种，这取决于远离感受野的刺激事件。具体而言，一个快速的眼球运动所产生的外周图像的移位，导致视觉灵敏度从关型到开型的短暂过渡约100毫秒。我们发现，这些神经节细胞接收输入从开和关双极细胞，和关输入通常占主导地位。外周移位强烈地以相反的方向调节这两种输入的强度，促进开通路并抑制关通路。此外，我们确定了某些宽场无长突细胞，有助于这种调制。去极化这种无长突细胞以与外周图像移位相同的方式影响附近的神经节细胞，促进On输入并抑制Off输入。这项研究说明了抑制性中间神经元如何快速控制电路中的信息流，从而在计算过程中显著改变主神经元的行为。眼睛将视觉所需的所有信息以视神经纤维上的电脉冲或尖峰的形式传达给大脑。这些尖峰是由视网膜神经节细胞产生的，视网膜的输出神经元。在视网膜功能的流行观点中，每个神经节细胞对视觉图像中的一个小区域（称为其感受野）做出反应，并且专门针对该窗口内的某些图像特征。当细胞遇到图像特征时，神经元通过发射一个或多个尖峰来做出反应。不同的神经元适应不同的特征。例如，一些神经节细胞在光线变暗时会放电，另一些则会在光线变亮时放电。在这里，我们展示了视网膜上图像的快速移动可以引起神经元首选功能：的戏剧性变化：例如，一个变暗的探测器可以短暂地变成一个变亮的探测器。我们探讨的机制，实现这样一个开关的功能调整，以及它可能对视觉处理的后果。周边图像移位在视网膜神经节细胞反应中产生从关闭主导到开启主导的瞬时切换。这种调节至少部分地在突触前发挥作用，推测是在双极细胞突触末端。
Retinal ganglion cells are commonly classified as On-center or Off-center depending on whether they are excited predominantly by brightening or dimming within the receptive field. Here we report that many ganglion cells in the salamander retina can switch from one response type to the other, depending on stimulus events far from the receptive field. Specifically, a shift of the peripheral image—as produced by a rapid eye movement—causes a brief transition in visual sensitivity from Off-type to On-type for approximately 100 ms. We show that these ganglion cells receive inputs from both On and Off bipolar cells, and the Off inputs are normally dominant. The peripheral shift strongly modulates the strength of these two inputs in opposite directions, facilitating the On pathway and suppressing the Off pathway. Furthermore, we identify certain wide-field amacrine cells that contribute to this modulation. Depolarizing such an amacrine cell affects nearby ganglion cells in the same way as the peripheral image shift, facilitating the On inputs and suppressing the Off inputs. This study illustrates how inhibitory interneurons can rapidly gate the flow of information within a circuit, dramatically altering the behavior of the principal neurons in the course of a computation. The eye communicates to the brain all the information needed for vision in the form of electrical pulses, or spikes, on optic nerve fibers. These spikes are produced by retinal ganglion cells, the output neurons of the retina. In a popular view of retinal function, each ganglion cell responds to a small region of interest in the visual image, known as its receptive field, and is specialized for certain image features within that window. When a cell encounters that image feature, the neuron responds by firing one or more spikes. Different neurons are tuned to different features. For example, some ganglion cells fire when light dims, others when it brightens. Here we show that a rapid shift in the image on the retina can cause a dramatic change in a neuron's preferred feature: For example, a dimming-detector can briefly turn into a brightening-detector. We explore the mechanisms that implement such a switch of feature tuning, and the consequences it might have for visual processing. A peripheral image shift produces a transient switch in retinal ganglion cell responses from Off-dominated to On-dominated. This modulation is exerted at least in part presynaptically, presumably at the bipolar cell synaptic terminal.