The nucleus accumbens (NAc) is the ventral part of the striatum and the interface between cognition, emotion, and action. It is composed of three major subnuclei: i.e., NAc core (NAcC), lateral shell (NAcLS), and medial shell (NAcMS), which exhibit functional heterogeneity. Thus, determining the synaptic inputs of the subregions of the NAc is important for understanding the circuit mechanisms involved in regulating different functions. Here, we simultaneously labeled subregions of the NAc with cholera toxin subunit B conjugated with multicolor Alexa Fluor, then imaged serial sections of the whole brain with a fully automated slide scanning system. Using the interactive WholeBrain framework, we characterized brain-wide inputs to the NAcC subdomains, including the rostral, caudal, dorsal, and ventral subdomains (i.e., rNAcC, cNAcC, dNAcC, and vNAcC, respectively) and the NAc subnuclei. We found diverse brain regions, distributed from the cerebrum to brain stem, projecting to the NAc. Of the 57 brain regions projecting to the NAcC, the anterior olfactory nucleus (AON) exhibited the greatest inputs. The input neurons of rNAcC and cNAcC are two distinct populations but share similar distribution over the same upstream brain regions, whereas the input neurons of dNAcC and vNAcC exhibit slightly different distributions over the same upstream regions. Of the 55 brain regions projecting to the NAcLS, the piriform area contributed most of the inputs. Of the 72 brain regions projecting to the NAcMS, the lateral septal nucleus contributed most of the inputs. The input neurons of NAcC and NAcLS share similar distributions, whereas the NAcMS exhibited brain-wide distinct distribution. Thus, the NAcC subdomains appeared to share the same upstream brain regions, although with distinct input neuron populations and slight differences in the input proportions, whereas the NAcMS subnuclei received distinct inputs from multiple upstream brain regions. These results lay an anatomical foundation for understanding the different functions of NAcC subdomains and NAc subnuclei.

中文翻译：

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伏隔核核心子域和伏隔核亚核的传入输入的全脑波动

伏隔核 (NAc) 是纹状体的腹侧部分，是认知、情绪和行动之间的界面。它由三个主要亚核组成：即 NAc 核 (NAcC)、外侧壳 (NAcLS) 和内侧壳 (NAcMS)，它们表现出功能异质性。因此，确定 NAc 子区域的突触输入对于理解参与调节不同功能的电路机制很重要。在这里，我们同时用与多色 Alexa Fluor 偶联的霍乱毒素亚基 B​​ 标记 NAc 的亚区域，然后使用全自动载玻片扫描系统对整个大脑的连续切片进行成像。使用交互式 WholeBrain 框架，我们表征了对 NAcC 子域的全脑输入，包括嘴侧、尾侧、背侧和腹侧子域（即 rNAcC、cNAcC、dNAcC 和 vNAcC，分别）和 NAc 亚核。我们发现了不同的大脑区域，从大脑分布到脑干，投射到 NAc。在投射到 NAcC 的 57 个大脑区域中，前嗅核 (AON) 表现出最大的输入。rNAcC 和 cNAcC 的输入神经元是两个不同的群体，但在相同的上游大脑区域具有相似的分布，而 dNAcC 和 vNAcC 的输入神经元在相同的上游区域表现出略有不同的分布。在投射到 NAcLS 的 55 个大脑区域中，梨状区域贡献了大部分输入。在投射到 NAcMS 的 72 个大脑区域中，外侧中隔核贡献了大部分输入。NAcC 和 NAcLS 的输入神经元具有相似的分布，而 NAcMS 则表现出全脑不同的分布。因此，NAcC 子域似乎共享相同的上游大脑区域，尽管输入神经元群体不同且输入比例略有不同，而 NAcMS 子核从多个上游大脑区域接收不同的输入。这些结果为理解 NAcC 亚结构域和 NAc 亚核的不同功能奠定了解剖学基础。