Yin Henry H, Ostlund Sean B, Knowlton Barbara J, Balleine Bernard W
Department of Psychology and Brain Research Institute, University of California, Los Angeles, Box 951563, Los Angeles, CA 90095-1563, USA.
Eur J Neurosci. 2005 Jul;22(2):513-23. doi: 10.1111/j.1460-9568.2005.04218.x.
Considerable evidence suggests that, in instrumental conditioning, rats learn the relationship between actions and their specific consequences or outcomes. The present study examined the role of the dorsomedial striatum (DMS) in this type of learning after excitotoxic lesions and reversible, muscimol-induced inactivation. In three experiments, rats were first trained to press two levers for distinct outcomes, and then tested after training using a variety of behavioural assays that have been established to detect action-outcome learning. In Experiment 1, pre-training lesions of the posterior DMS abolished the sensitivity of rats' instrumental performance to both outcome devaluation and contingency degradation when tested in extinction, whereas lesions of the anterior DMS had no effect. In Experiment 2, both pre-training and post-training lesions of the posterior DMS were equally effective in reducing the sensitivity of performance both to devaluation and degradation treatments. In Experiment 3, the infusion of muscimol into the posterior DMS selectively abolished sensitivity of performance to devaluation and contingency degradation without impairing the ability of rats to discriminate either the instrumental actions performed or the identity of the earned outcomes. Taken together, these results suggest that the posterior region of the DMS is a crucial neural substrate for the acquisition and expression of action-outcome associations in instrumental conditioning.
大量证据表明，在工具性条件反射中，大鼠学习动作与其特定后果或结果之间的关系。本研究考察了兴奋性毒性损伤和可逆性、蝇蕈醇诱导失活后背内侧纹状体（DMS）在这类学习中的作用。在三个实验中，大鼠首先接受训练，按压两个杠杆以获得不同结果，然后在训练后使用各种已确立的行为测试来检测动作-结果学习。在实验1中，后DMS的训练前损伤消除了大鼠在消退测试中工具性表现对结果贬值和意外性降低的敏感性，而前DMS的损伤则没有影响。在实验2中，后DMS的训练前和训练后损伤在降低表现对贬值和降低处理的敏感性方面同样有效。在实验3中，向DMS后部注入蝇蕈醇选择性地消除了表现对贬值和意外性降低的敏感性，而不损害大鼠区分所执行的工具性动作或所获结果的身份的能力。综合来看，这些结果表明DMS的后部区域是工具性条件反射中动作-结果关联获取和表达的关键神经基质。
