Title Page
국문 초록
Abstract
Contents
Abbreviations 9
I. Introduction 10
1. Distinguishing similar memory episodes 10
2. Dentate gyrus role in pattern separation 10
3. Cellular organization of dentate gyrus 11
4. Functional role of dentate gyrus primary neurons. 11
II. Materials and Research Methods 15
1. Animals 15
2. Virus injection and preparation for head fixation 15
3. Behavioural training 15
4. Behaviour control apparatus 16
5. Chemogenetic inhibition 16
6. Chronic implantation of electrode 17
7. Recording sessions 17
8. Anatomy and immunohistochemistry 18
9. Data acquisition and spike sorting 18
10. Data analysis and statistics 19
11. Model 20
III. Results 21
1. Cell-specific modulation of mossy cell activity. 21
2. Experimental setup 23
3. Design of the Shift and Change experiments 25
4. Effect of MC suppression on the place field formation in DG neurons 28
5. Distinct response of DG neurons to spatial and non-spatial alteration 31
6. DG neurons population response to the spatial and non-spatial alteration 36
7. Effect of MCs suppression on spatio-temporal response of DG neurons to spatial alteration 38
8. Effect of MCs suppression on spatio-temporal response of DG neurons to non spatial alteration 40
9. A theoretical mechanism of detection of a change in an environment 43
10. Neural network model of the dentate gyrus function 45
11. Simulation of spatial and non-spatial alteration. 49
IV. Discussion 52
1. Effect of spatial and non-spatial alteration with/without MCs suppression 52
2. Role of MCs in detection of a change 54
V. Conclusion 58
VI. Bibliography 59
Figure 1. Schematic representation of information flow in the brain. 14
Figure 2. Expression of virus in mouse dentate gyrus. 22
Figure 3. Verification of recording location. 24
Figure 4. Experimental timeline and setup 26
Figure 5. Place field activity at initial section of recording session in vehicle and CNO conditions. 29
Figure 6. Comparison of recorded cells features in vehicle and CNO conditions... 30
Figure 7. Examples of DG cells response to shift of the landmark in vehicle and CNO conditions. 32
Figure 8. Examples of DG cells response to change of the landmark in vehicle and... 34
Figure 9. Sorted population firing maps for shift and change experiment. 37
Figure 10. Population Vector (PV) correlation in the Shift experiment. 39
Figure 11. Population Vector (PV) correlation in the Change experiment. 41
Figure 12. Average of population vector correlation in Shift and Change experiments. 42
Figure 13. Dentate gyrus connectivity scheme used for the theoretical model. 44
Figure 14. Simulation model connectivity scheme. 46
Figure 15. Simulation model algorithm and input. 48
Figure 16. Simulation results of the Shift experiment. 50
Figure 17. Simulation results of the Change experiment 51
Figure 18. Proposed mechanism of novelty detection in DG. 57