CC BY
8B-I-10
Fiber-based methods for deep brain calcium recording in behaving mice
L. Fu1-2-3. Z.Qi23, X. Li23
1Huazhong University of Science and Technology, wnlo, wuhan, China
2Collaborative Innovation Center for Biomedical Engineering, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, Hubei 430074, China 3Britton Chance Center and MOE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
Neuronal calcium transients are reflection of neuronal action potential firing. The microscopy should be able to catch the dynamic process of calcium signal transients with a good temporal and spatial resolution for deep brain. Here, we developed a multi-channel fiber photometry system for recording neural activities in several brain areas of an animal or in different animals [1]. With this system, we simultaneously acquired calcium signals from the bilateral barrel cortices of a head-restrained mouse or from the orbitofrontal cortices of three freely moving mice. In addition, a GRIN lens based confocal microscope is also developed to detect the specific cell type calcium signal of deep brain area with single cell resolution [2]. With a 500 p,m diameter GRIN lens implanted into the deep brain, approximately hundred neurons can be imaged at 15 frames per second in vivo, which is beyond out of the traditional two-photon microscopy. The activity signals of neurons have been efficiently recorded in orbitofrontal cortices, hippocampus, and striatum nucleus in head-fixed mice with different diameter GRIN lens by this system. Our new results about visual cue-dependent memory circuit for place navigation in hippocampus of mice will be also presented. As spatial coding is an important way for neurons to process information, it will be suitable for researches in deep brain function. In sum, relaying the deep brain calcium signals to the surface with optical fibers is an efficient approach to extend the in vivo optical detection methods. The methods we developed will potentially boost new discoveries in neural circuitry investigations, and finally facilitate the finding of new treatments of psychiatric diseases.
References
[1] V. Emiliani, A.E. Cohen, K. Deisseroth, M. Hausser, "All-Optical Interrogation of Neural Circuits," The Journal of Neuroscience 35(41), 13917-13926 (2015).
[2] Ghosh KK, Burns LD, Cocker ED, Nimmerjahn A, Ziv Y, Gamal AE, Schnitzer MJ, "Miniaturized integration of a fluorescence microscope," Nat Methods 8(10), 871-8 (2011).
