A rhodopsin-based two-photon voltage indicator for all-optical mapping of synaptic connectivity in vivo

基于视紫红质的双光子电压指示器，用于体内突触连接的全光映射

• 批准号: 442616457
• 负责人: Dr. Christiane Grimm
• 金额: --
• 依托单位: Department of Biological Sciences
• 依托单位国家: 德国
• 项目类别: Research Fellowships
• 财政年份: 2020
• 资助国家: 德国
• 起止时间: 2019-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/442616457?language=en
• 关键词: rhodopsin; based; two; photon; voltage

Linking the behavior of an animal to the activity of a distinct neuronal cell population is a long-standing aim of neuroscience. Additionally, generating the connectivity matrix of this cell population is needed to understand how the mammalian brain computes and encodes behavior. The development of a method to simultaneously record and modulate the activity of a large neuronal cell population, which allows non-destructive and chronic mapping of synaptic connections, will hence transform neurosciences. The current state-of-the-art method for high-throughput monitoring of neuronal activity is two-photon calcium imaging, which provided fundamental insights over the last decades. However, as calcium sensors only report supra-threshold changes in membrane potential, information encoded in sub-threshold voltage changes remains elusive. Further, calcium indicators are insensitive to hyperpolarization of the cell membrane, which limits the mapping to excitatory connections. A transition from calcium to voltage imaging would overcome those limitations and appears as the next challenge in neuroscience. To be effective, an ideal optical sensor of voltage should be used with two-photon excitation to increase imaging depth, reduce phototoxicity, and background fluorescence, but current voltage sensors have poor two-photon performances. To tackle this challenge, this project will develop a genetically-encoded two-photon voltage sensor and combine it with a two-photon activatable optogenetic actuator. This genetically-encoded, two-photon activated tool will allow to map synaptic connectivity and strength in an all-optical experiment. In contrast to previous approaches, this will enable studies of functional connections in vivo with single cell resolution in a high throughput and chronic fashion.

将动物的行为与不同神经元细胞群的活动联系起来是神经科学的长期目标。此外，需要生成该细胞群的连接矩阵，以了解哺乳动物大脑如何计算和编码行为。因此，开发一种同时记录和调节大型神经元细胞群活动的方法，可以对突触连接进行非破坏性和慢性映射，将改变神经科学。目前用于高通量监测神经元活动的最先进方法是双光子钙成像，其在过去几十年中提供了基本的见解。然而，由于钙传感器仅报告膜电位的阈上变化，因此在阈下电压变化中编码的信息仍然难以捉摸。此外，钙指示剂对细胞膜的超极化不敏感，这限制了对兴奋性连接的映射。从钙到电压成像的过渡将克服这些限制，并成为神经科学的下一个挑战。为了有效，理想的电压光学传感器应该与双光子激发一起使用，以增加成像深度，减少光毒性和背景荧光，但目前的电压传感器具有较差的双光子性能。为了应对这一挑战，该项目将开发一种遗传编码的双光子电压传感器，并将其与双光子可激活的光遗传致动器联合收割机相结合。这种基因编码的双光子激活工具将允许在全光学实验中绘制突触连接和强度。与以前的方法相比，这将使得能够以高通量和慢性方式研究体内功能连接与单细胞分辨率。