Amygdaloid projections to the ventral striatum in mice: direct and indirect chemosensory inputs to the brain reward system
Amygdaloid projections to the ventral striatum in mice: direct and indirect chemosensory inputs to the brain reward system
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DOI：
10.3389/fnana.2011.00054
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发表时间：
2011-08-22
影响因子：
2.9
通讯作者：
Martinez-Garcia, Fernando
中科院分区：
文献类型：
--
作者：
Novejarque, Amparo;Gutierrez-Castellanos, Nicolas;Martinez-Garcia, Fernando
啮齿类动物是研究社会性行为的神经基础的良好模型。最近在老鼠身上的发现揭示了一些触发两性间吸引的信息素分子的分子特性。然而，介导这种基本社会性行为的神经通路仍然难以捉摸。由于先前的研究表明多巴胺能被盖状体-纹状体通路与信息素奖励无关，本报告通过研究化学感觉杏仁核到腹侧纹状体-白质的直接和间接投射的通道追踪实验，探索了连接马鼻系统和被盖状体-纹状体系统（边缘基底神经节）的替代通路。通过分析葡聚糖胺和氟金注射在腹侧纹状体的杏仁核逆行转运，以及葡聚糖胺注射在杏仁核腹侧纹状体的顺行标记，研究了杏仁核向伏隔核、嗅结节和邻近结构的投射。这种顺行和逆行追踪实验的结合揭示了从犁鼻皮层到腹侧纹状体的直接投射，以及通过杏仁核基底外侧不同核的间接投射。直接投射神经主要支配嗅结节和胼胝体岛，而间接投射神经分布更广，到达相同的结构以及伏隔核的壳和核。这些途径可能介导对信息素的先天反应（直接投射）和对相关化学感觉和非化学感觉刺激的条件反应（间接投射）。比较研究表明，在所有被研究的羊膜脊椎动物中都存在类似的连接，并且可能构成大多数脊椎动物（包括人类）对同种动物的情绪反应的基本回路。
Rodents constitute good models for studying the neural basis of sociosexual behavior. Recent findings in mice have revealed the molecular identity of the some pheromonal molecules triggering intersexual attraction. However, the neural pathways mediating this basic sociosexual behavior remain elusive. Since previous work indicates that the dopaminergic tegmento-striatal pathway is not involved in pheromone reward, the present report explores alternative pathways linking the vomeronasal system with the tegmento-striatal system (the limbic basal ganglia) by means of tract-tracing experiments studying direct and indirect projections from the chemosensory amygdala to the ventral striato-pallidum. Amygdaloid projections to the nucleus accumbens, olfactory tubercle, and adjoining structures are studied by analyzing the retrograde transport in the amygdala from dextran amine and fluorogold injections in the ventral striatum, as well as the anterograde labeling found in the ventral striato-pallidum after dextran amine injections in the amygdala. This combination of anterograde and retrograde tracing experiments reveals direct projections from the vomeronasal cortex to the ventral striato-pallidum, as well as indirect projections through different nuclei of the basolateral amygdala. Direct projections innervate mainly the olfactory tubercle and the islands of Callega, whereas indirect projections are more widespread and reach the same structures and the shell and core of nucleus accumbens. These pathways are likely to mediate innate responses to pheromones (direct projections) and conditioned responses to associated chemosensory and non-chemosensory stimuli (indirect projections). Comparative studies indicate that similar connections are present in all the studied amniote vertebrates and might constitute the basic circuitry for emotional responses to conspecifics in most vertebrates, including humans.