Levita Liat, Dalley Jeffrey W, Robbins Trevor W
Department of Experimental Psychology, University of Cambridge, Downing Street, CB2 3EB, Cambridge, UK.
Behav Brain Res. 2002 Dec 2;137(1-2):115-27. doi: 10.1016/s0166-4328(02)00287-5.
A role for the nucleus accumbens (NAcc) and its dopamine (DA) innervation in fear and fear learning is supported by a large body of evidence, which has challenged the view that the NAcc is solely involved in mediating appetitive processes. Unfortunately, due to conflicting findings in the aversive conditioning literature the role of the NAcc in aversive conditioning remains unclear. This review focuses on the results of recent in vivo microdialysis studies that have examined the release of NAcc DA during Pavlovian aversive conditioning. In addition, we present additional new findings, which re-examine the involvement of NAcc DA in aversive conditioning. DA release was measured in the NAcc core using in vivo microdialysis during discrete cue Pavlovian aversive conditioning in four experiments. In all cases no change in DA levels was observed either during training or in response to the CS presentations despite robust behavioural evidence of discrete cue Pavlovian aversive conditioning. These findings contrast with some previous studies that show that primary and conditioned aversive stimuli increase DA release in the NAcc. We suggest that the inconsistencies in the literature might be due to procedural differences in the measurement of aversive conditioning, and the precise location of the probe in the NAcc region. Hence, rather than discount an involvement of NAcc DA in affective processes, we propose that functionally dissociable sub-regions of the NAcc may contribute to different aspects of Pavlovian aversive learning.
大量证据支持伏隔核（NAcc）及其多巴胺（DA）神经支配在恐惧和恐惧学习中的作用，这一观点挑战了伏隔核仅参与介导奖赏性过程的看法。不幸的是，由于厌恶条件作用文献中的研究结果相互矛盾，伏隔核在厌恶条件作用中的作用仍不明确。本综述聚焦于近期的体内微透析研究结果，这些研究考察了巴甫洛夫式厌恶条件作用过程中伏隔核多巴胺的释放情况。此外，我们还展示了其他新发现，这些发现重新审视了伏隔核多巴胺在厌恶条件作用中的作用。在四个实验中，通过体内微透析在离散线索巴甫洛夫式厌恶条件作用期间测量伏隔核核心的多巴胺释放。在所有情况下，尽管有确凿的行为证据表明存在离散线索巴甫洛夫式厌恶条件作用，但在训练期间或对条件刺激呈现的反应中均未观察到多巴胺水平的变化。这些发现与之前的一些研究形成对比，那些研究表明原发性和条件性厌恶刺激会增加伏隔核中的多巴胺释放。我们认为，文献中的不一致可能是由于厌恶条件作用测量的程序差异以及探针在伏隔核区域的精确位置所致。因此，我们并非否定伏隔核多巴胺参与情感过程，而是提出伏隔核功能上可分离的子区域可能对巴甫洛夫式厌恶学习的不同方面有贡献。
