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23 February 2009 Fluorescence lifetime images of different green fluorescent proteins in fly brain
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Proceedings Volume 7180, Photons and Neurons; 71800D (2009)
Event: SPIE BiOS, 2009, San Jose, California, United States
The mechanisms of learning and memory are the most important functions in an animal brain. Investigating neuron circuits and network maps in a brain is the first step toward understanding memory and learning behavior. Since Drosophila brain is the major model for understanding brain functions, we measure the florescence lifetimes of different GFP-based reporters expressed in a fly brain. In this work, two Gal4 drivers, OK 107 and MZ 19 were used. Intracellular calcium ([Ca2+]) concentration is an importation indicator of neuronal activity. Therefore, several groups have developed GFP-based calcium sensors, among which G-CaMP is the most popular and reliable. The fluorescence intensity of G-CaMP will increase when it binds to calcium ion; however, individual variation from different animals prevents quantitative research. In this work, we found that the florescence lifetime of G-CaMP will shrink from 1.8 ns to 1.0 ns when binding to Ca2+. This finding can potentially help us to understand the neuron circuits by fluorescence lifetime imaging microscopy (FLIM). Channelrhodopsin-2 (ChR2) is a light-activated ion-channel protein on a neuron cell membrane. In this work, we express ChR2 and G-CaMP in a fly brain. Using a pulsed 470-nm laser to activate the neurons, we can also record the fluorescence lifetime changes in the structure. Hence, we can trace and manipulate a specific circuit in this animal. This method provides more flexibility in brain research.
© (2009) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Sih-Yu Lai, Y. Y. Lin, A. S. Chiang, and Y. C. Huang "Fluorescence lifetime images of different green fluorescent proteins in fly brain", Proc. SPIE 7180, Photons and Neurons, 71800D (23 February 2009);

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