Durand S E, Heaton J T, Amateau S K, Brauth S E
Department of Psychology, University of Maryland, College Park 20742-4411, USA.
J Comp Neurol. 1997 Jan 13;377(2):179-206. doi: 10.1002/(sici)1096-9861(19970113)377:2<179::aid-cne3>3.0.co;2-0.
A feature of the telencephalic vocal control system in the budgerigar (Melopsittacus undulatus) that has been hypothesized to represent a profound difference in organization from the oscine vocal system is its reported lack of an inherent circuit through the anterior forebrain. The present study reports anatomical connections that indicate the existence of an anterior forebrain circuit comparable in important ways to the "recursive" pathway of oscine songbirds. Results from anterograde and retrograde tracing experiments with biocytin and fluorescently labeled dextran amines indicate that the central nucleus of the anterior archistriatum (AAc) is the source of ascending projections upon the oval nuclei of the anterior neostriatum and ventral hyperstriatum (NAo and HVo, respectively). Efferent projections from the latter nuclei terminate in the lateral neostriatum afferent to AAc, thereby forming a short recurrent pathway through the pallium. Previously reported projections from HVo and NAo upon the magnocellular nucleus of the lobus parolfactorius (LPOm), and after LPOm onto the magnocellular nucleus of the dorsal thalamus (DMm; G.F. Striedter [1994] J. Comp. Neurol. 343:35-56), are confirmed. A specific projection from DMm onto NAom is also demonstrated; therefore, a recurrent pathway through the basal forebrain also exists in the budgerigar vocal system that is similar to the anterior forebrain circuit of oscine songbirds. Parallels between these circuits and mammalian basal ganglia-thalamo-cortical circuits are discussed. It is hypothesized that vocal control nuclei of the avian anterior neostriatum may perform a function similar to the primate supplemental motor area.
虎皮鹦鹉（Melopsittacus undulatus）端脑发声控制系统的一个特征被认为与鸣禽发声系统在组织上存在显著差异，即据报道它缺乏一条贯穿前脑前部的固有回路。本研究报告了解剖学连接，表明存在一条在前脑前部的回路，在重要方面与鸣禽的“递归”通路相当。用生物胞素和荧光标记的葡聚糖胺进行的顺行和逆行追踪实验结果表明，前古纹状体中央核（AAc）是投射到前新纹状体和腹侧超纹状体的椭圆形核（分别为NAo和HVo）上的上行投射的来源。后两个核的传出投射终止于向AAc传入的外侧新纹状体，从而形成一条通过大脑皮层的短反馈回路。先前报道的从HVo和NAo投射到嗅觉叶大细胞核（LPOm），以及从LPOm投射到背侧丘脑大细胞核（DMm；G.F. Striedter [1994] J. Comp. Neurol. 343:35 - 56）的投射得到了证实。还证明了从DMm到NAom的特定投射；因此，虎皮鹦鹉发声系统中也存在一条通过基底前脑的反馈回路，类似于鸣禽的前脑前部回路。讨论了这些回路与哺乳动物基底神经节 - 丘脑 - 皮质回路之间的相似性。据推测，鸟类前新纹状体的发声控制核可能执行与灵长类补充运动区类似的功能。
