Fig. 2
From: Activation of serotonin neurons promotes active persistence in a probabilistic foraging task
Reward statistics and task performance. a In each trial, reward probabilities were drawn from one of the three exponentially decreasing functions, all sharing the same time constant but with a different scaling factor, labeled high, medium, and low. Dots mark hypothetical values; solid lines are averages derived from data. b Bar plot showing the average number of rewards in each of the trial types (n = 16 mice). Dashed lines mark maximal values (assuming mice stay in place and poke indefinitely). c Schematic drawing of an optimal-agent’s behavior during foraging. When plotting the average cumulative reward as a function of time from reward site exit, the average reward rate is the slope of the line that connects this curve at the time of leaving with the origin. Thus the slope of this line is maximal when it is tangent to the curve. Consequently, better or worse trials result in later or earlier leaving times, respectively (vertical lines and arrows). d Left: Scatter plot of reward rate at leaving vs. average reward rate. Each circle represents one mouse (n = 16). Dashed line is the unity diagonal and red line is a linear regression curve, with its correlation coefficient shown as well (p < 0.001). Right: Bar plot showing the average reward rate at leaving and the average reward rate. p > 0.05, Wilcoxon signed-rank test. e Cumulative distributions of the number of pokes per trial for the three trial types, averaged across mice (n = 16). f Bar plot showing the average number of pokes in each of the trial types. Bars on the left represent real data, and bars on the right represent shuffled data. Asterisk indicates significant effect (p < 0.05, ANOVA). g Cumulative distributions of the estimated reward probability after the last poke in a trial (i.e., at the time of switching) for the three trial types, averaged across mice (n = 16). h Bar plot showing the average reward probability after the last poke. Bars on the left represent real data, and bars on the right represent shuffled data. Asterisk indicates significant difference between trial types, p < 0.05, ANOVA
