The synapse between photoreceptors and OFF bipolar cells - molecular mechanism of parallel processing of visual signals

光感受器和视锥双极细胞之间的突触是视觉系统的第一个突触。光感受器阵列的活动的时间和空间模式构成了视觉信息的主要表征，通过调节谷氨酸的胞吐作用将视觉信息转化为渐进的信号，并最终分配到不同的双极细胞通道并行运行。为此，高度专门化的带状突触已经进化出来。在这项研究中，我们将研究突触前和突触后的参数，这对决定这个特殊突触的传递函数(S)至关重要。在突触前，我们将重点研究完整的条带结构的作用以及囊泡释放的动力学。在突触后部位，将结合不同的扩散距离来研究谷氨酸受体的亚单位组成。这些参数决定了突触后反应的幅度和动力学，因此是在视网膜网络中编码视觉信息的基础。

The synapse between photoreceptors and cone bipolar cells is the first synapse of the visual system. The temporal and spatial pattern of activity of the photoreceptor array constitutes the primary representation of visual information, which is transformed into a gradual signal by modulating exocytosis of glutamate, and it is eventually distributed to different bipolar cell channels operating in parallel. For this purpose, the highly specialized ribbon synapse has evolved. In this research proposal we will investigate pre- and postsynaptic parameters crucially determining the transfer function(s) at this particular synapse. Presynaptically, we will focus on the role of an intact ribbon structure as well as on the kinetics of vesicle release. On the postsynaptic site, the subunit composition of glutamate receptors in combination with varying diffusion distances will be investigated. These parameters shape the amplitude and kinetics of the postsynaptic response and thus are fundamental for encoding visual information within the retinal network.