Program in Neuroscience, University of Maryland, School of Medicine Baltimore, MD, USA.
Front Integr Neurosci. 2010 Oct 20;4:126. doi: 10.3389/fnint.2010.00126. eCollection 2010.
The nucleus accumbens (NA) has been hypothesized to be part of a circuit in which cue-evoked information about expected outcomes is mobilized to guide behavior. Here we tested this hypothesis using a Pavlovian reinforcer devaluation task, previously applied to assess outcome-guided behavior after damage to regions such as the orbitofrontal cortex and amygdala that send projections to NA. Rats with sham lesions or neurotoxic lesions of either the core or shell subdivision of NA were trained to associate a 10-s CS+ with delivery of three food pellets. After training, half of the rats in each lesion group received food paired with illness induced by LiCl injections; the remaining rats received food and illness unpaired. Subsequently, responding to the CS+ was assessed in an extinction probe test. Both sham and lesioned rats conditioned to the CS+ and formed a conditioned taste aversion. However only sham rats reduced their conditioned responding as a result of reinforcer devaluation; devalued rats with lesions of either core or shell showed levels of responding that were similar to lesioned, non-devalued rats. This impairment was not due to the loss of motivational salience conferred to the CS+ in lesioned rats as both groups responded similarly for the cue in conditioned reinforcement testing. These data suggest that NA core and shell are part of a circuit necessary for the use of cue-evoked information about expected outcomes to guide behavior.
伏隔核（NA）被假设为一个回路的一部分，在这个回路中，关于预期结果的线索诱发信息被调动起来指导行为。在这里，我们使用一种条件性强化物贬损任务来检验这一假设，该任务以前曾被用于评估眶额皮层和杏仁核等区域受损后对结果导向行为的影响，这些区域向 NA 投射。假损伤或 NA 的核心或壳亚区的神经毒性损伤的大鼠接受训练，将 10 秒的 CS+与三粒食物丸的传递联系起来。在训练后，每组损伤大鼠的一半接受与 LiCl 注射引起的疾病相关的食物配对；其余大鼠接受食物和疾病不配对。随后，在消退探测测试中评估对 CS+的反应。假损伤和损伤大鼠都对 CS+进行了条件化，形成了条件性味觉厌恶。然而，只有假损伤大鼠由于强化物贬损而减少了条件反应；接受核心或壳损伤的损伤大鼠的反应水平与损伤、未贬损的大鼠相似。这种损伤不是由于损伤大鼠的 CS+失去了动机显著性，因为两组大鼠在条件强化测试中对线索的反应相似。这些数据表明，NA 核心和壳是一个回路的一部分，该回路对于利用线索诱发的关于预期结果的信息来指导行为是必要的。
