Fig. 8 | Nature Communications

Fig. 8

From: The cost of obtaining rewards enhances the reward prediction error signal of midbrain dopamine neurons

Fig. 8

Learning speed test. a Mean learning process of monkeys P and S. The proportion of R+ choices is plotted as a function of the trial. The green and purple points indicate data from high-cost and low-cost trial, respectively. The dotted lines represent smoothed learning process. The cumulative exponential functions were fitted to the data points and represented as the solid lines. b The log ratio between the fitting parameters a in the high- and low-cost conditions when the data were fit with a cumulative exponential function (*P < 0.05; two-tailed Wilcoxon’s signed-rank test). Black circles and error bars indicate mean and SEM. c The log ratio between the fitting parameters b in the high- and low-cost conditions when the data were fit with a cumulative exponential function. d The log ratio between the learning rate parameter α in the high- and low-cost conditions when the data were fit with a reinforcement-learning model. e The log ratio between the fitting parameter β in the high- and low-cost conditions when the data were fit with a reinforcement-learning model

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