果蝇对二阶运动信息处理的神经机制

Motion perception is essential to the survival and reproduction of organisms in nature. Second-order motion, which breaks the coherent spatiotemporal correlations in luminance in first-order motion, is perceived by plenty of animals including fruit fly Drosophila and human beings. Though psychophysical and electrophysiological studies in mammals have provided some information on where and how the second-order motion is perceived, the underlying neural mechanism remains largely unknown. In this project, a behavior paradigm to study second-order motion detection in free walking flies was established. In this paradigm, wild-type flies exhibited tracking behavior to second-order motion and their corresponding first-order motion. The neurons involved in the second-order motor information processing of Drosophila melanogaster will be screened by neuronal blocking, and confirmed by a variety of blocking or activating candidate neurons. Furthermore, multiple functional imaging techniques (CaLexA、TRIC、Calcium Imaging) will be used to detect the functional activity of candidate neurons in second-order motion detection. Finally, GRASP and Synaptic-GRASP will be employed to explore the structural and functional relationship between these candidate neurons. The second-order motor neural circuit will reveal through this study, which provided a reference for the discovery of the related neural circuit in other organisms.

在自然界中，运动检测对于生物的生存繁衍至关重要。虽然二阶运动中运动目标的亮度打破了一阶运动中所遵循的时空关联，但包括果蝇和人在内的许多动物依然能够感知到二阶运动。哺乳动物的心理物理学以及电生理学方面的实验已经为二阶运动的感知与处理提供了一些线索，然而其对应的神经机制却并不清楚。本项目建立了自由爬行果蝇的二阶运动检测范式，且野生型果蝇对二阶运动及其对应的一阶运动均能进行追踪。在此基础上，将通过神经元阻断筛选参与果蝇二阶运动信息处理的神经元；通过多种阻断或活化候选神经元确认其参与二阶运动检测；采用多种功能成像技术（TRIC、CaLexA和钙成像等）检测候选神经元二阶运动检测中的功能活性；最后采用GRASP和Synaptic-GRASP方法揭示这些候选神经元之间可能存在的结构与功能联系。通过本研究深入揭示二阶运动的神经环路，为其它生物的相关神经环路的研究提供参考。