Robbins T W, Cador M, Taylor J R, Everitt B J
Department of Experimental Psychology, University of Cambridge, U.K.
Neurosci Biobehav Rev. 1989 Summer-Fall;13(2-3):155-62. doi: 10.1016/s0149-7634(89)80025-9.
Stimuli with formerly motivationally neutral properties gain incentive properties from their predictive association with primary reinforcement, and are termed conditioned reinforcers. Infusions of the indirect dopamine (DA) agonist d-amphetamine into the ventral striatum selectively enhanced responding for a light that was positively correlated with water. These selective stimulatory effects were blocked by 6-OHDA lesions of the ventral, but not dorsal striatum, and resembled those produced by DA itself when infused into the ventral striatum. However, the choice of the lever producing the conditioned reinforcer was not affected by ventral striatal DA depletion. This choice was, however, attenuated by excitotoxic lesions of the basolateral nucleus of the amygdala, suggesting an interaction between this structure and DA-dependent processes of the ventral striatum in the processes by which reward-related stimuli come to affect action. Parallel findings were obtained using a second order schedule of sexual reinforcement. Other observations indicated that the amygdala lesion did not impair the discriminative property of the reward-related stimuli, or affect primary motivation. Experiments using explicit conditional visuo-spatial discrimination tasks suggest that similar discriminative properties are preserved following DA depletion from the ventral, but not the dorsal, striatum. These results possibly represent a dissociation between stimulus-response (or habit) and stimulus-reward associative mechanisms, modulated respectively by the dorsal and ventral striatum.
具有先前动机中性属性的刺激物通过与初级强化物的预测性关联而获得激励属性，被称为条件性强化物。向腹侧纹状体注射间接多巴胺（DA）激动剂d-苯丙胺可选择性增强对与水呈正相关的光的反应。这些选择性刺激作用被腹侧而非背侧纹状体的6-OHDA损伤所阻断，并且类似于向腹侧纹状体注射DA本身所产生的作用。然而，产生条件性强化物的杠杆选择不受腹侧纹状体DA耗竭的影响。然而，杏仁核基底外侧核的兴奋性毒性损伤减弱了这种选择，这表明在奖励相关刺激影响行为的过程中，该结构与腹侧纹状体的DA依赖性过程之间存在相互作用。使用二级性强化程序也获得了类似的结果。其他观察结果表明，杏仁核损伤不会损害奖励相关刺激的辨别属性，也不会影响初级动机。使用明确的条件性视觉空间辨别任务的实验表明，腹侧而非背侧纹状体DA耗竭后，类似的辨别属性得以保留。这些结果可能代表了分别由背侧和腹侧纹状体调节的刺激-反应（或习惯）和刺激-奖励联想机制之间的分离。
