Ⅰ. Introduction 1 1.1 Circadian rhythm 1 1.2 Cell atlas of the SCN 7 1.3 Neural network of the SCN 15 1.4 Circadian organization of behaviors 19 1.5 Circadian organization of social behaviors 21 1.6 Purpose 26 ⅠI. Materials and Methods 27 ⅠII. Results 34 3.1 Circadian profile of social prioritization 34 3.2 The role of SCN VIP neuron and its downstream projection on circadian rhythm in social prioritization 37 3.3 VIP-VIPR2 signaling in RE is necessary for circadian rhythm in social prioritization 39 3.4 In vivo responsiveness of RE VIPR2 neuron on circadian time information and social cues 41 3.5 Optogenetic manipulation of RE VIPR2 neuron and its downstream projection to mPFC is responsible for circadian rhythm in social prioritization 42 3.6 Behavioral consequences of functional VIPR2 expression in social and reproductive behavior during naturalistic interaction 43 ⅠV. Discussion 84 V. References 94 VI. Abstract in Korean 107
