Article Figures & Data
Figures
- Figure 1.
Voltammetry recording sites. NAcc core recording locations are represented as filled black circles and NAcc shell locations as filled gray circles. Figures modified from Paxinos and Watson (2005).
- Figure 2.
Training schedule and behavior on PR sessions. A, Schedule for behavioral session (n = 20 rats). B, Average number of food pellets earned for each PR session. C, Average breakpoint for each PR session. D, Percentage of the operant requirement of the previous trial that was completed on the last, breakpoint trial.
- Figure 3.
Dopamine release to trial-onset cues and reward delivery with fixed costs. A, Examples of dopamine release in the NAcc core to reward-related stimuli in the first, intermediate, and last trials. Current at the peak oxidation potential of dopamine is plotted as a function of time, with the inset showing the cyclic voltammogram identifying the detected current as dopamine. Below are two-dimensional pseudocolor plots of cyclic voltammograms over time. Rectangular dashed lines denote the cue onset, and square dashed lines denote the pellet delivery. B, Peak dopamine response in the NAcc core (n = 13) and shell (n = 9) to cue presentation. C, Peak dopamine response in the NAcc core and shell to pellet delivery.
- Figure 4.
Dopamine release to trial-onset cues with escalating costs. A, Examples of dopamine release in the NAcc core to the presentation of trial-onset cues are shown for the first, intermediate, and last trials. Current at the peak oxidation potential of dopamine is plotted as a function of time, with the inset showing the cyclic voltammogram identifying the detected current as dopamine. Below are two-dimensional pseudocolor plots of cyclic voltammograms over time. Rectangular dashed lines denote the cue onset. B, C, Peak dopamine response in the NAcc core (n = 13) and shell (n = 9) to cue presentation as a function of trials aligned to the first trial (B) and the last trial (C).
- Figure 5.
No difference in dopamine release to trial-onset cues between FR and PR sessions in either the NAcc core or shell. Voltammetry data from the NAcc core (n = 13; A) and NAcc shell (n = 9; B) found in Figures 3 and 4 are replotted to highlight the lack of difference in dopamine release to trial-onset cues between these behavioral sessions.
- Figure 6.
Dopamine release to pellet delivery increases with escalating costs. A, Examples of dopamine release in the NAcc core to food pellet delivery in progressively later trials in a PR session. Current at the peak oxidation potential of dopamine is plotted as a function of time, with the inset showing the cyclic voltammogram identifying the detected current as dopamine. Below are two-dimensional pseudocolor plots of cyclic voltammograms over time. Rectangular dashed lines denote the pellet delivery. B, C, Peak dopamine response to pellet delivery increased with higher costs in both the NAcc core (n = 13; B) and NAcc shell (n = 9; C).
- Figure 7.
Temporal costs mediated elevated dopamine release to pellet delivery in PR sessions. A, Time to complete a trial and the number of lever presses required to complete a trial were highly correlated in PR sessions (n = 20 rats). B, Reward-evoked dopamine release in the NAcc scaled with increasing trial duration in both PR (n = 22) and low-effort yoked (n = 5) sessions. **p < 0.01, ***p < 0.001.
- Figure 8.
Dissociation of dopamine release to cues and rewards in PR sessions. A, Peak dopamine release in the NAcc core to trial-onset cues is plotted together with dopamine release to reward delivery aligned to the last completed trial (n = 13 rats). B, Average dopamine response in the NAcc core to cue presentation in short (10–25 s), medium (25–100 s), and long (>100 s) duration trials. C, Average dopamine response in the NAcc core to pellet delivery in short (10–25 s), medium (25–100 s), and long (>100 s) duration trials. D, Peak dopamine release in the NAcc shell to reward predictive cues is plotted together with dopamine release to reward delivery aligned to the last completed trial (n = 9 rats). E, Average dopamine response in the NAcc shell to cue presentation in short (10–25 s), medium (25–100 s), and long (>100 s) duration trials. F, Average dopamine response in the NAcc shell to pellet delivery in short (10–25 s), medium (25–100 s), and long (>100 s) duration trials.
