Ito Rutsuko, Robbins Trevor W, Pennartz Cyriel M, Everitt Barry J
Department of Experimental Psychology, University of Cambridge, Cambridge CB2 3EB, United Kingdom.
J Neurosci. 2008 Jul 2;28(27):6950-9. doi: 10.1523/JNEUROSCI.1615-08.2008.
The nucleus accumbens (NAc) has been implicated in a variety of associative processes that are dependent on the integrity of the amygdala and hippocampus (HPC). However, the extent to which the two subregions of the NAc, the core and shell, form differentiated circuits within the amygdala- and hippocampal-ventral striatal circuitry remains unclear. The present study investigated the effects of selective excitotoxic lesions of the nucleus accumbens shell or core subregion on appetitive elemental cue and context conditioning, shown previously to be dependent on the basolateral amygdala and hippocampus, respectively. Rats were trained sequentially to acquire discrete conditioned stimulus-sucrose conditioning, followed by spatial context-sucrose conditioning in a place preference apparatus characterized by three topographically identical chambers, the chambers being discriminable only on the basis of path integration. NAc shell lesions selectively impaired the acquisition of conditioned place preference and the use of spatial information to retrieve information about a discrete cue, whereas, as expected, NAc core lesions attenuated the acquisition of cue conditioning compared with sham rats. In a subsequent experiment, disconnection of the HPC from the NAc shell using unilateral asymmetric lesions of each structure resulted in a pattern of impairment in place conditioning and context-dependent cue retrieval similar to that produced by NAc shell lesions. These data not only suggest that the NAc core and shell subregions subserve distinct associative processes but also that the NAc shell and HPC are important functional components of a limbic corticostriatal network involved in spatial context conditioning.
伏隔核（NAc）已被证明参与了多种依赖于杏仁核和海马体（HPC）完整性的联想过程。然而，NAc的两个亚区，即核心区和壳区，在杏仁核 - 海马体 - 腹侧纹状体回路中形成分化回路的程度仍不清楚。本研究调查了选择性兴奋性毒性损伤伏隔核壳区或核心亚区对食欲性基本线索和情境条件反射的影响，先前的研究表明，这两种条件反射分别依赖于基底外侧杏仁核和海马体。大鼠在一个由三个地形相同的腔室组成的位置偏好装置中，依次接受离散条件刺激 - 蔗糖条件反射训练，随后进行空间情境 - 蔗糖条件反射训练，这些腔室仅通过路径整合来区分。伏隔核壳区损伤选择性地损害了条件性位置偏好的获得以及利用空间信息检索关于离散线索的信息的能力，而正如预期的那样，与假手术大鼠相比，伏隔核核心区损伤减弱了线索条件反射的获得。在随后的实验中，通过对每个结构进行单侧不对称损伤，使海马体与伏隔核壳区断开连接，导致位置条件反射和情境依赖性线索检索出现类似伏隔核壳区损伤所产生的损伤模式。这些数据不仅表明伏隔核核心区和壳区亚区参与不同的联想过程，还表明伏隔核壳区和海马体是参与空间情境条件反射的边缘皮质纹状体网络的重要功能组成部分。
