Schreyer Helene Marianne, Gollisch Tim
Department of Ophthalmology, University Medical Center Göttingen, 37073 Göttingen, Germany; Bernstein Center for Computational Neuroscience Göttingen, 37077 Göttingen, Germany.
Neuron. 2021 May 19;109(10):1692-1706.e8. doi: 10.1016/j.neuron.2021.03.015. Epub 2021 Apr 1.
The retina dissects the visual scene into parallel information channels, which extract specific visual features through nonlinear processing. The first nonlinear stage is typically considered to occur at the output of bipolar cells, resulting from nonlinear transmitter release from synaptic terminals. In contrast, we show here that bipolar cells themselves can act as nonlinear processing elements at the level of their somatic membrane potential. Intracellular recordings from bipolar cells in the salamander retina revealed frequent nonlinear integration of visual signals within bipolar cell receptive field centers, affecting the encoding of artificial and natural stimuli. These nonlinearities provide sensitivity to spatial structure below the scale of bipolar cell receptive fields in both bipolar and downstream ganglion cells and appear to arise at the excitatory input into bipolar cells. Thus, our data suggest that nonlinear signal pooling starts earlier than previously thought: that is, at the input stage of bipolar cells.
视网膜将视觉场景分解为并行的信息通道，这些通道通过非线性处理提取特定的视觉特征。第一个非线性阶段通常被认为发生在双极细胞的输出端，这是由突触末端非线性的神经递质释放导致的。相比之下，我们在此表明，双极细胞自身在其体细胞的膜电位水平上可作为非线性处理元件。对蝾螈视网膜双极细胞的细胞内记录显示，双极细胞感受野中心内视觉信号频繁地进行非线性整合，影响人工刺激和自然刺激的编码。这些非线性特性在双极细胞和下游神经节细胞中均赋予了对低于双极细胞感受野尺度的空间结构的敏感性，并且似乎产生于双极细胞的兴奋性输入。因此，我们的数据表明，非线性信号汇总比之前认为的开始得更早：即在双极细胞的输入阶段。
