Updating of action-outcome associations is prevented by inactivation of the posterior pedunculopontine tegmental nucleus
Updating of action-outcome associations is prevented by inactivation of the posterior pedunculopontine tegmental nucleus
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DOI：
10.1016/j.nlm.2013.03.002
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发表时间：
2013-05-01
影响因子：
2.7
通讯作者：
Winn, Philip
中科院分区：
文献类型：
--
作者：
MacLaren, Duncan A. A.;Wilson, David I. G.;Winn, Philip
桥脑脚被盖核(PPTg)位于基底节和脑干之间的关键位置，能够影响和调节所有水平的基底节和皮质纹状体的活动，也是脑干、网状结构和运动控制回路的关键组成部分。与其解剖位置一致，PPTg此前已被证明处理快速、显著的感觉输入，是帕金森病治疗的目标，并与联想学习有关。我们明确研究了后部pPPTg(PPPTg)在行动-结果过程中的作用，在行动-结果过程中，行动是以获得预期结果的目标为导向的。我们评估了在通过微量注射GABA激动剂蝇油或对照注射生理盐水使pPPTg失活的过程中，大鼠对行为(杠杆按压)和结果(食物奖励)之间的偶然性退化的敏感性。为了应对杠杆压力和食物奖励之间的偶然性的退化，生理盐水处理的大鼠迅速降低了杠杆压力的速率，而蝇油处理的大鼠(pPPTg失活)保持了先前的杠杆压力速率。相反，当杠杆按压和食物奖励之间的偶然性不变时，生理盐水和麝香酚处理组的大鼠保持其先前的杠杆按压速率。这表明，pPPTg对于更新行动和结果之间的关联至关重要，但对于先前学习的关联的持续表现则不是如此。这些结果与PPTG在“高级”联想学习中的作用是一致的，并首次证明了脑干在行动-结果学习中的作用。(C)2013 Elsevier Inc.保留所有权利。
The pedunculopontine tegmental nucleus (PPTg) is in a pivotal position between the basal ganglia and brainstem: it is able to influence and regulate all levels of basal ganglia and corticostriatal activity as well as being a key component of brainstem reticular and motor control circuitry. Consistent with its anatomical position, the PPTg has previously been shown to process rapid, salient sensory input, is a target for Parkinson's disease treatments and has been implicated in associative learning. We explicitly investigated the role of the posterior pPPTg (pPPTg) in action-outcome processes, where actions are performed with the goal-directed aim of obtaining an anticipated outcome. We assessed rats' sensitivity to degradation of the contingency between actions (lever pressing) and outcomes (food reward) during either inactivation of pPPTg by microinjection of the GABA agonist muscimol or control infusions of saline. In response to the degradation of contingency between lever press and food reward, saline treated rats rapidly reduced rates of lever pressing whereas muscimol treated rats (pPPTg inactivation) maintained previous lever pressing rates. In contrast, when the contingency between lever press and food reward was unchanged saline and muscimol treated rats maintained their previous rates of lever pressing. This shows that the pPPTg is critically required for updating associations between actions and outcomes, but not in the continued performance of previously learned associations. These results are consistent with a role for the PPTg in 'higher-order' associative learning and are the first to demonstrate a brainstem role in action-outcome learning. (C) 2013 Elsevier Inc. All rights reserved.