Fig. 4.

Phasic activation of DA neurons to the base stimulus, comparison stimulus, and reward delivery. Normalized DA population responses to different periods of the task (shadows ±1 SEM). (Left) Responses to f₁ (gray shaded region), aligned to f₁ onset. (Center) Responses to f₂ (gray shaded region), aligned to f₂ onset. (Right) Responses to reward delivery, after the decision report (slender gray region), aligned to PB. (A) Responses for difficulty (uncertainty) groups: low (navy blue) and high (light blue) difficulty. (B) Responses for trial outcome groups: correct (blue) and error (red) trials.