Fig. 2: GPe and DLPFC encoding of exploration-exploitation behavior.

a dorsolateral prefrontal cortex (DLPFC) (top, 12,035 recorded trials of 325 neurons) and external segment of the globus pallidus (GPe) (bottom, 17,327 recorded trials of 233 neurons) mean ± SEM z-normalized firing rates (FRs) around the reward outcome of trial N and subsequent cue choice in trial N + 1. The shaded gray area indicates the window for calculating the mean FR, as shown in the bar graphs on the right. Left—FRs around the reward outcome in trial N for successful (blue, reward) and unsuccessful (red, no reward) trials, with a z-score baseline from the two seconds before reward claiming. Right—FRs around cue choice in trial N + 1, with a z-score baseline from the two seconds before trial initiation. p-values are from two-tailed t tests comparing FRs. b DLPFC (top, 12,035 recorded trials of 325 neurons) and GPe (bottom, 17,327 recorded trials of 233 neurons) mean ± SEM z-normalized FRs around cue choice in exploratory trials (green, cue switch) and non-exploratory trials (orange, same cue as previous trial). p-values are from two-tailed t tests comparing FRs. c Trial type definitions: (1) Directed exploration—following unsuccessful trials with a choice switch. (2) Perseveration—following unsuccessful trials without a choice switch. (3) Random exploration—following successful trials with a choice switch. (4) Exploitation—following successful trials without a choice switch. Colors match those in panels (a) and (b). d Comparison of DLPFC (top, 1373 recorded trials of 325 neurons) and GPe (bottom, 2963 recorded trials of 233 neurons) FRs around choice selection in directed exploration and perseveration. Bar graphs show the mean ± SEM FR during the two seconds preceding cue choice. p-values (Bonferroni corrected for multiple comparisons) are from two-tailed t tests. e Comparison of DLPFC (top, 10,662 recorded trials of 325 neurons) and GPe (bottom, 14,364 recorded trials of 233 neurons) FRs in random exploration and exploitation. Bar graphs show the mean ± SEM FR during the two seconds before choice selection. p-values (Bonferroni corrected for multiple comparisons) are from two-tailed t tests. f Left—Mean ± SEM DLPFC and GPe FR leading to cue choice in the four trial types. Right—FR ratio relative to exploitation trials. p-values (Bonferroni corrected for multiple comparisons) are from two-tailed t-tests comparing FRs between random exploration, perseveration, directed exploration, and exploitation trials. Each bar chart is overlaid with 100 randomly selected data points falling within one standard deviation of the mean. For the full distribution of data points, please see Supplementary Fig. 3.