Aix-Marseille Université, Marseille Cedex 3, France.
Learn Mem. 2011 Jun 17;18(7):444-51. doi: 10.1101/lm.2123811. Print 2011 Jul.
Considerable evidence has shown a clear dissociation between the dorsomedial (DMS) and the dorsolateral (DLS) striatum in instrumental conditioning. In particular, DMS activity is necessary to form action-outcome associations, whereas the DLS is required for developing habitual behavior. However, few studies have investigated whether a similar dissociation exists in more complex goal-directed learning processes. The present study examined the role of the two structures in such complex learning by analyzing the effects of excitotoxic DMS and DLS lesions during the acquisition and extinction of spatial alternation behavior, in a continuous alternation T-maze task. We demonstrate that DMS and DLS lesions have opposite effects, the former impairing and the latter improving animal performance during learning and extinction. DMS lesions may impair the acquisition of spatial alternation behavior by disrupting the signal necessary to link a goal with a specific spatial sequence. In contrast, DLS lesions may accelerate goal-driven strategies by minimizing the influence of external stimuli on the response, thus increasing the impact of action-reward contingencies. Taken together, these results suggest that DMS- and DLS-mediated learning strategies develop in parallel and compete for the control of the behavioral response early in learning.
大量证据表明，在工具性条件作用中，背侧纹状体的背内侧（DMS）和背外侧（DLS）区域之间存在明显的分离。特别是，DMS 活动对于形成动作-结果关联是必要的，而 DLS 则对于发展习惯行为是必需的。然而，很少有研究探讨在更复杂的目标导向学习过程中是否存在类似的分离。本研究通过在连续交替 T 迷宫任务中分析 DMS 和 DLS 损伤对空间交替行为获得和消退的影响，来研究这两个结构在这种复杂学习中的作用。我们证明 DMS 和 DLS 损伤具有相反的效果，前者在学习和消退过程中损害动物的表现，而后者则改善动物的表现。DMS 损伤可能通过破坏将目标与特定空间序列联系起来的信号，从而损害空间交替行为的获得。相比之下，DLS 损伤可能通过最小化外部刺激对反应的影响，从而增加动作-奖励关联的影响，加速目标驱动策略的发展。总之，这些结果表明，DMS 和 DLS 介导的学习策略在学习早期平行发展，并相互竞争以控制行为反应。
