Evidence for "direct" and "indirect" pathways through the song system basal ganglia
Evidence for "direct" and "indirect" pathways through the song system basal ganglia
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DOI：
10.1002/cne.20464
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发表时间：
2005-03-28
影响因子：
2.5
通讯作者：
Perkel, DJ
中科院分区：
文献类型：
--
作者：
Farries, MA;Ding, L;Perkel, DJ
鸣禽的鸣唱学习依赖于一种被称为“前脑前通路”的回路，该回路包括鸟类基底节的一个专门区域。这个区域，X区，嵌入在被认为与纹状体同源的端脑结构中，纹状体是哺乳动物基底节的输入结构。X区有许多与哺乳动物纹状体相似的特征，但也有独特的特征，包括主要是直接支配丘脑的刺状投射神经元，以及一种在生理上与哺乳动物苍白球记录的神经元相似的细胞类型。我们提出X区是纹状体和苍白球的混合体，具有与哺乳动物基底节环路相同的功能组织。利用电生理学和解剖学方法，我们发现X区包含哺乳动物纹状体丘脑直接通路的功能类似物：纹状体棘神经元的轴突与苍白球细胞的体细胞和树突密切接触。苍白球神经元的一个子集直接投射到丘脑。令人惊讶的是，我们发现有证据表明，许多苍白球状细胞可能不投射到丘脑，而是参与了哺乳动物“间接”途径的功能类似物，这可能与直接途径的影响相反。我们的结果加深了我们对信息如何通过X区流动的理解，并为振荡器中的歌曲学习使用类似于哺乳动物基底节依赖的运动学习形式的生理机制的观点提供了更多支持。(C)2005年Wiley-Liss，Inc.
Song learning in oscine birds relies on a circuit known as the "anterior forebrain pathway," which includes a specialized region of the avian basal ganglia. This region, area X, is embedded within a telencephalic structure considered homologous to the striatum, the input structure of the mammalian basal ganglia. Area X has many features in common with the mammalian striatum, yet has distinctive traits, including largely aspiny projection neurons that directly innervate the thalamus and a cell type that physiologically resembles neurons recorded in the mammalian globus pallidus. We have proposed that area X is a mixture of striatum and globus pallidus and has the same functional organization as circuits in the mammalian basal ganglia. Using electrophysiological and anatomical approaches, we found that area X contains a functional analog of the "direct" striatopallidothalamic pathway of mammals: axons of the striatal spiny neurons make close contacts on the somata and dendrites of pallidal cells. A subset of pallidal neurons project directly to the thalamus. Surprisingly, we found evidence that many pallidal cells may not project to the thalamus, but rather participate in a functional analog of the mammalian "indirect" pathway, which may oppose the effects of the direct pathway. Our results deepen our understanding of how information flows through area X and provide more support for the notion that song learning in oscines employs physiological mechanisms similar to basal ganglia-dependent forms of motor learning in mammals. (C) 2005 Wiley-Liss, Inc.