Extended Data Fig. 5: Uncertainty-related signals in subcortical regions during exploration and exploitation.
We show subcortical activation associated with the uncertainty prediction difference for exploration, exploitation, and their difference. Activation is shown during the decision phase, and when relevant, during the outcome phase. We used bilateral masks and averaged the results over both hemispheres for each ROI. a, Amygdala represents uncertainty prediction difference during exploration more strongly than during exploitation (paired t-test: uncertainty prediction difference, explore vs exploit: t(23) = 3.5, p=0.002, d=0.71, 95% confidence interval (CI)=[6 23.5]). b, Activation patterns in VS during decision (left panel) and outcome phases (right panel) suggest its primary involvement is during exploitation. VS represented both a negative uncertainty prediction difference during the decision phase during exploitation (t(23)=−2.4, p=0.02, d=−0.49, 95% confidence interval=[−15.8 −1.3]) and the payoff during the outcome phase during both exploration and exploitation but it did so more strongly during exploitation (paired t-test: payoff for explore vs exploit (t(23) = −2.3, p=0.033, d=−0.47, 95% CI=[−21.2 −0.96]). c, Finally, VTA activity reflected uncertainty during both exploration and exploitation in the decision phase (exploration: t(23) = 2.3, p= 0.03, d=0.47, 95% CI=[1.94 40]; exploitation: t(23) = −3, p=0.007, d=−0.6, 95% CI=[−25.3 −4.4]). (n = 24; error bars are SEM across participants).
