講師資料
Talks：
Using two photon and endoscope to observe light responsive cells in the suprachiasmatic nucleus in mouse
Name：
陳示國 (Shih-Kuo Chen)
Position：
Professor
Affiliation：
Department of Life Science, National Taiwan University
Email：
Photo：
Research Interests：
Intrinsic photosensitive retinal ganglion cells
Circadian photoentrainment
In vivo calcium image in mice
Selected Publications：
1. Lee C-C, Liang F, Lee I-C, Lu T-H, Shan Y-Y, Jeng C-F, Zou Y-F, Yu H-T, Chen S-K*. External light-dark cycle shapes gut microbiota through intrinsically photosensitive retinal ganglion cells. EMBO Rep. 2022 Jun 7;23(6):e52316.
2. Chien Y-F, Lin J-Y, Yeh P-T, Hsu H-J, Tsai Y-H, Chen S-K *, and Chu S-W*. Dual GRIN lens two-photon endoscopy for high-speed volumetric and deep brain imaging. Biomed. Opt. Express, 2020 Dec; 12, 162-172
3. Fan M-Y, Chang Y-T, Chen C-L, Wang W-H, Pan M-K, Chen W-P, Huang W-Y, Xug Z, Huang H-E, Cheng T, Plikush MV, Chen S-K*, Lin S-J*. External light activates hair follicle stem cells through eyes via an ipRGC–SCN–sympathetic neural pathway. PNAS. 2018 Jul 17;115(29)
4. Fernandez DC^, Chang Y-T^, Hattar S, Chen S-K*. Architecture of retinal projections to the central circadian pacemaker. PNAS. 2016; 113(21):6047-52.
Abstract：
For circadian clock, one of the major criteria is that this clock can be entrained by external cycle. In mammal, the strongest external environmental cue to entrain the central clock at the suprachiasmatic nucleus (SCN) is light dark cycle. To convey light information for photoentrainment, a specific group of intrinsically photosensitive retinal ganglion cells (ipRGCs) which express photopigment melanopsin, is essential. After light exposure, ipRGC could release glutamate and PACAP directly through their axonal terminal in the SCN to advance or delay the clock depends on the circadian time of the animal. Since the SCN is located at the bottom of the hypothalamus, how does light input trigger the neuronal response in individual SCN neuron remain unclear. Here, using two photon microscope with GRIN lens, we could record activity of SCN neurons using GCaMP reporter. By analyze the calcium response of SCN neurons, we found that SCN neurons have distinct light response. In addition, the activity correlation analysis suggests that the connection circuit is different at distinct ZT time point. Together, our results suggest that the SCN is composed of a dynamic functional circuit. SCN neurons may not form a strong and stable connection throughout the day. Therefore, a flexible populational coding may be utilized for circadian time keeping.