Article Figures & Data
Figures
- Figure 1.
Schematic representation of lesion to the LHb. A, Photomicrograph of electrolytic lesions to the LHb. B, Three animals were excluded from the first experiment due to inaccurate lesion or extensive damage. This yielded the following group sizes: Sham, n = 11; LHb Lesion, n = 10. C, Two animals were excluded from the second experiment due to inaccurate lesion or extensive damage. This yielded the following group sizes: Sham, n = 11; LHb Lesion, n = 12. All coordinates are in millimeters relative to bregma.
- Figure 2.
LHb lesions abolish the effect of specific inhibition on choice. A, Backward training did not reveal any difference between the two groups of rats and responding remained similar whether the stimuli were absent or present (Pre vs S). B, Instrumental training was successful and lever-press responding increased as the ratio parameters increased across sessions. LHb lesions had no effect on this responding. C, Performance during the two stimuli was assessed relative to performance in their absence by subtracting this latter baseline activity to reveal the net effect of the predictive cues on choice and the vigor of action selection. In Sham rats, the stimuli biased choice away from the action earning the outcome that was negatively predicted (Same), toward the action earning the other outcome (Different). This choice pattern was abolished in rats with LHb lesions. Performance on each action for each animal is indicated in light gray full circles. Error bars denote ±1 SEM.
- Figure 3.
LHb lesions spare the effect of positive predictors on choice. A, Forward training was successful; responding increased across sessions and it was higher in the presence of the stimuli (S) than in their absence (Pre). The difference between the S and Pre periods grew larger across training; however, this growth was slightly impaired in rats with LHb lesions. Nevertheless, all animals clearly showed evidence of successful learning. B, Instrumental training was successful and lever-press responding increased as the ratio parameters increased across sessions. LHb lesions had no effect on this responding. C, Performance during the two stimuli was assessed in the manner described previously. In all groups, a stimulus predicting a particular outcome biased choice toward an action earning the same outcome. Performance on each action for each animal is indicated in light gray full circles. Error bars denote ±1 SEM.
- Figure 4.
LHb lesions spared sensitivity to changes in outcome value on choice. A, Retraining of the instrumental actions occurred smoothly and LHb lesions had no effect on responding. B, All animals displayed value-based choice. Performance on the action delivering the valued outcome was higher than performance on the action delivering the outcome that had just been devalued. Performance on each action for each animal is indicated in light gray full circles. Error bars denote ±1 SEM.
- Figure 5.
LHb lesions impair the reversal of Pavlovian contingencies. A, Reversal training occurred smoothly, as responding was higher in the presence of the stimuli than in their absence. Lesions of the LHb had no effect on performance. B, Instrumental training was successful and lever-press responding increased as the ratio parameters increased across sessions. LHb lesions had no effect on this responding. C, Sham animals adapted to the reversed contingency. Prereversal and postreversal performance reveals that a stimulus biased choice toward the action earning the same outcome. Performance on each action for each animal is indicated in light gray full circles. D, LHb lesions disrupted learning about the reversed contingency. Prereversal performance revealed that the stimulus biased choice toward an action earning the same outcome; however, this bias was lost after reversal training. Performance on each action for each animal is indicated in light gray full circles. Error bars denote ±1 SEM.
- Figure 6.
LHb inputs onto the RMTg are necessary for outcome-specific inhibition. A, eGFP staining revealed substantial AAV-Cre infection in the RMTg. Pn, Pontine nuclei; scp, superior cerebellar peduncle. B, The localization of cell bodies infected with AAV-Cre was mostly restricted to the RMTg of rats included in the experiment. Distances are indicated in millimeters from bregma. C, D, Cre-recombinase-positive neurons were found in the LHb of Control rats but not Casp3 rats. E, The immunofluorescence quantification revealed a higher number of Cre-recombinase-positive neurons in the LHb of Control rats compared with Casp3 rats (Caps3; F(1,18) = 54.18, p < 0.05). F, Backward training did not reveal any difference between the two groups of rats and responding was lower when the stimuli were absent than when they were present (Pre vs S). G, Instrumental training was successful and lever-press responding increased as the ratio parameters increased across sessions. There was no difference between groups. F, Performance during the two stimuli was assessed in the manner described previously. In Control rats, the stimuli biased choice away from the action earning the outcome that was negatively predicted (Same), toward the action earning the other outcome (Different). This pattern of choice was reversed in rats with selective ablation of LHb neurons projecting onto the RMTg. Performance on each action for each animal is indicated in light gray full circles. I, Instrumental training was successful and lever-press responding increased as the ratio parameters increased across sessions. There was no difference between groups. J, All animals displayed value-based choice. Performance on the action delivering the valued outcome was higher than performance on the action delivering the outcome that had just been devalued. Performance on each action for each animal is indicated in light gray full circles. Error bars denote ±1 SEM.
