Double dissociation of the effects of selective nucleus accumbens core and shell lesions on impulsive-choice behaviour and salience learning in rats
Double dissociation of the effects of selective nucleus accumbens core and shell lesions on impulsive-choice behaviour and salience learning in rats
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DOI：
10.1111/j.1460-9568.2005.04388.x
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发表时间：
2005-11-01
影响因子：
3.4
通讯作者：
Yee, BK
中科院分区：
文献类型：
--
作者：
Pothuizen, HHJ;Jongen-Rêlo, AL;Yee, BK
脑桥核可以被细分为至少两个解剖学上不同的亚区：背外侧的“核心”和腹内侧的“壳”，这种区别可能延伸到功能分离。在这里，我们对比了选择性兴奋性毒性核心和内侧壳病变的影响冲动选择行为使用延迟奖励选择范式和差异奖励低反应率（DRL）测试，对一种形式的显着性学习被称为潜在抑制（LI）。核心病变导致增强冲动的选择，证明了一个更明显的转变，从选择一个不断加强的杠杆，部分加强杠杆，当杠杆按下和奖励交付之间的延迟是有选择地施加在前者。核心病变还损害了DRL任务的表现，该任务需要在固定的时间内保持反应以获得奖励。内侧壳病变对这两项任务没有影响，但取消了LI效应，这是由刺激预暴露的失败所揭示的，以延缓随后的条件反射，在病变动物的主动回避程序中的刺激。正如预期的那样，选择性核心病变避免了LI。这里展示的双重解离支持核的核心和外壳之间的功能隔离，并增加重量的假设，即核的核心，而不是壳，亚区的核的选择行为的控制优先参与延迟强化条件下，并在抑制控制目标导向的行为。
The nucleus accumbens can be subdivided into at least two anatomically distinct subregions: a dorsolateral 'core' and a ventromedial 'shell', and this distinction may extend to a functional dissociation. Here, we contrasted the effects of selective excitotoxic core and medial shell lesions on impulsive-choice behaviour using a delayed reward choice paradigm and a differential reward for low rates of responding (DRL) test, against a form of salience learning known as latent inhibition (LI). Core lesions led to enhanced impulsive choices as evidenced by a more pronounced shift from choosing a continuously reinforced lever to a partially reinforced lever, when a delay between lever press and reward delivery was imposed selectively on the former. The core lesions also impaired performance on a DRL task that required withholding the response for a fixed period of time in order to earn a reward. Medial shell lesions had no effect on these two tasks, but abolished the LI effect, as revealed by the failure of stimulus pre-exposure to retard subsequent conditioning to that stimulus in an active avoidance procedure in the lesioned animals. As expected, selective core lesions spared LI. The double dissociations demonstrated here support a functional segregation between nucleus accumbens core and shell, and add weight to the hypothesis that the core, but not the shell, subregion of the nucleus accumbens is preferentially involved in the control of choice behaviour under delayed reinforcement conditions and in the inhibitory control of goal-directed behaviour.