Extended Data Fig. 7: Repeated associative learning using the same odour cues.
From: Dopamine facilitates associative memory encoding in the entorhinal cortex
(a). To test the effect of repeated exposure to the same odour pair during associative learning, sessions with Odour A, -B, -C and -D were repeated for 10 days in Sim1xDAT mice injected with AAV-flex-GFP (n = 4 mice, without laser). (b). Learning curves between Day 1 – Day 4 and Day 5 – Day 10. In Day 1 – Day 4, mice gradually learned Odour C and Odour D as in the regular new association experiment with novel odour pairs. However, after Day 5, mice showed better performance for Odour C and Odour D from the initial trials. This was confirmed with increased correct rate for Odour C/D on trials 1 – 20 in Day 5 – 10 compared to that in Day 1 – 4 (bottom left,p = 3.5e-4, ANOVA with post-hoc Tukey test, p = 0.0025). (c). Fan cell trajectories for Odour A, -B, -C and -D in T5 during Day 1 – Day 4 (left, n = 101 cells) and during Day 5 – 10 (right, n = 93 cells). (d). Fan cells showed A-B separation and A-1 overlap in Day 1-4, but this representation disappeared after mice were overtrained. These results further support the idea that fan cells were needed only when new associative memory is formed.
