Centre for Integrative Neuroscience, Bernstein Centre for Computational Neuroscience (BCCN), Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.
Trends Neurosci. 2013 Aug;36(8):480-8. doi: 10.1016/j.tins.2013.04.006. Epub 2013 May 22.
Image processing begins in the retina, where neurons respond with graded voltage changes that must be converted into spikes. This conversion from 'analog' to 'digital' coding is a fundamental transformation carried out by the visual system, but the mechanisms are still not well understood. Recent work demonstrates that, in vertebrates, graded-to-spiking conversion of the visual signal begins in the axonal system of bipolar cells (BCs), which transmit visual information through ribbon-type synapses specialized for responding to graded voltage signals. Here, we explore the evidence for and against the idea that ribbon synapses also transmit digital information. We then discuss the potential costs and benefits of digitization at different stages of visual pathways in vertebrates and invertebrates.
图像处理始于视网膜，其中神经元通过分级电压变化做出反应，这些变化必须转换为尖峰。这种从“模拟”到“数字”编码的转换是视觉系统进行的基本转换，但机制仍未得到很好的理解。最近的研究表明，在脊椎动物中，视觉信号的分级到尖峰的转换始于双极细胞（BC）的轴突系统，BC 通过专门用于响应分级电压信号的带状突触传递视觉信息。在这里，我们探讨了在脊椎动物和无脊椎动物的视觉通路的不同阶段，带状突触是否也传递数字信息的观点的证据。然后，我们讨论了在脊椎动物和无脊椎动物的视觉通路的不同阶段进行数字化的潜在成本和收益。
