Distinct kinds of novelty processing differentially increase extracellular dopamine in different brain regions
Distinct kinds of novelty processing differentially increase extracellular dopamine in different brain regions
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DOI：
10.1111/j.1460-9568.2006.04658.x
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发表时间：
2006-03-01
影响因子：
3.4
通讯作者：
Cools, A
中科院分区：
文献类型：
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作者：
De Leonibus, E;Verheij, MMM;Cools, A
已知行为相关的新刺激可以激活中皮质边缘多巴胺能（DAergic）系统。在这项研究中，我们测试了该系统对不同类型的新颖性处理的反应性。使用体内微透析技术，我们测量了大鼠在社交学习任务期间不同 DAergic 末端区域的细胞外多巴胺 (DA) 量。在第一阶段（40 分钟）中，将大鼠暴露于两只以前从未遇到过的幼体（即无条件的新鲜感）。随后，将动物分为三组：对照组不接受任何其他刺激；对照组不接受任何刺激。歧视组接触一名熟悉的青少年和一名新的青少年（即新刺激歧视）；识别组重新接触两个熟悉的青少年（即熟悉度识别）。在内侧前额叶皮层和伏隔核壳中，DA 都随着青少年的第一次出现而增加，表明这两种结构都参与处理无条件的社会新奇事物。在新的刺激辨别过程中，我们发现前额叶皮层没有变化，尽管与接触两个熟悉的青少年的组相比，伏贝壳中的DA增加了，这表明该壳也参与了处理新的社会刺激辨别。所呈现的刺激均不会影响累积核中的 DA。这项研究提供了原始证据，表明各个末端区域的 DA 与新颖性处理的不同方面存在差异耦合。
Behaviourally relevant novel stimuli are known to activate the mesocorticolimbic dopaminergic (DAergic) system. In this study we tested the reactivity of this system in response to distinct kinds of novelty processing. Using the in vivo microdialysis technique, we measured extracellular amounts of dopamine (DA) in different DAergic terminal regions during a social learning task in rats. In the first session (40 min) rats were exposed to two never previously encountered juveniles (i.e. unconditional novelty). Afterwards, the animals were divided into three groups: Control group was not exposed to any other stimulus; Discrimination group was exposed to one familiar and one new juvenile (i.e. novel stimulus discrimination); and Recognition group was re-exposed to the two familiar juveniles (i.e. familiarity recognition). In both the medial prefrontal cortex and the nucleus accumbens shell DA increased in response to the first presentation of the juveniles, showing that both structures are involved in processing unconditional social novelty. During the novel stimulus discrimination, we found no change in the prefrontal cortex, although DA increased in the accumbal shell in comparison with the group exposed to two familiar juveniles, showing that the shell is also involved in processing novel social stimulus discrimination. None of the stimuli presented affected DA in the accumbal core. This study provided the original evidence that DA in the various terminal regions is differentially coupled to distinct aspects of novelty processing.