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

视锥双极细胞与光感受器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视觉信息的主要表示，其通过调节谷氨酸的胞吐作用而转化为渐进信号，并且其最终被分配到并行操作的不同双极细胞通道。为了这个目的，高度特化的带状突触已经进化出来。在这项研究计划中，我们将研究突触前和突触后参数，这些参数决定了这个特定突触的传递函数。突触前，我们将集中在一个完整的带状结构的作用，以及对囊泡释放的动力学。在突触后部位，将研究谷氨酸受体的亚基组成以及不同的扩散距离。这些参数塑造了突触后反应的幅度和动力学，因此是视网膜网络内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.