Fig. 5.

Influence of the group on individual behaviors and on the DA system. a Experimental paradigm: two different groups of mice were studied in parallel in two Souris City environments (1 and 2). After 5 weeks, their switching pattern were evaluated (step 1). Mice from each Souris City were split in lowest (red) and highest (black) switchers. The two populations were then mixed and the lowest switchers from the two environments were grouped together (same for the highest switchers). After three weeks of sucrose versus water, the switching patterns were re-evaluated (step 2) for both residents (Res.) and incomers (Inc.). b Cumulative distribution of SW for steps 1 (purple) and 2 (green) (D = 0.2069, p = 0.57). c Cumulative left or right turns for two different mice upon water and sucrose bottle swapping in step 1 (black) and step 2 (red). The incomer mouse #5 switched less, whereas the resident mouse #6 switched more in step 2 compared to step 1. d Switch variation between step 1 and 2 (∆SW) for incomers and residents (two-sample t-test, t(27) = 2.9401). e (Left) No difference in SW in step 1 between lowest switchers of the two different Souris City, whether they will be subsequently considered as incomers or residents. (Right) SW is different for the same two groups after step 2 (Two-sample t-test (t = 3.5914, **p < 0.01)). f Firing activity of VTA DA neurons from incomers and residents (frequency and SWB: two-sample Wilcoxon, W = 17,750 and W = 18,319 respectively, p < 0.001). ***p < 0.001, **p < 0.01, *p < 0.05