Cell Survival in a Neural Circuit for Learning

像人类一样，幼年鸣禽在一个敏感的时期学习模仿成年鸣禽的发声方式。 发展。也像人类一样，鸣禽的发声模式由一个前脑网络控制，该网络包括 运动前、纹状体和听觉通路，用于处理声音和手势。这项建议旨在 了解这些途径是如何相互作用来产生稳定的发声模式的。我们的工作假说表明 习得的歌曲来自运动前和纹状体通路的整合，编码了刻板印象和变量 各自的发声模式。这个简单的假设清楚地预测了改变对发声的影响 运动前通路和纹状体通路的相对强度。例如，我们已经证明削弱前置马达 成年鸟类的路径(通过部分消融)产生高度可变的歌唱，使人联想到学习 很幼稚。然而，当鸟类随后恢复稳定的歌唱时，成年的发声模式显示出惊人的韧性 在1周内。这种恢复依赖于听觉反馈，这表明成人发声恢复包括 类似于指导青少年学习的教育机制。最近，我们设计了一个实验来 在成年鸟类中确定这些指导机制的神经轨迹，并证明它们不会撒谎 在它们长期推测的位置--纹状体通路内。在这里，我们建议进行实验1。)测试我们的模型 幼鸟运动前和纹状体通路的功能和2。)通过以下方法确定神经轨迹和机制 哪种听觉反馈能促进(青少年)发声学习和(成人)保持稳定的歌唱。 这些实验将为鸣禽发声控制的功能结构提供新的信息 网络--这一知识将为类似神经区域的功能结构提供新的见解 它控制着人类的发声学习。 1

Like humans, juvenile songbirds learn to imitate the vocal patterns of an adult during a sensitive period of development. Also like humans, songbird vocal patterns are controlled by a forebrain network that includes pre-motor, striatal, and auditory pathways for processing vocal sounds and gestures. This proposal seeks to understand how these pathways interact to produce stable vocal patterns. Our working hypothesis states that learned song results from an integration of pre-motor and striatal pathways encoding stereotyped and variable vocal patterns, respectively. This simple hypothesis makes clear predictions about the vocal effects of altering the relative strength of pre-motor and striatal pathways. For example, we have shown that weakening the premotor pathway in adult birds (via partial ablation) produces highly variable singing reminiscent of a learning juvenile. However, adult vocal patterns show surprising resilience as birds subsequently recover stable song within 1 week. This recovery depends on auditory feedback, indicating that adult vocal recovery involves instructive mechanisms similar to those that guide juvenile learning. Recently, we designed an experiment to identify the neural locus of these instructive mechanisms in adult birds and demonstrated that they cannot lie within their long-presumed location - the striatal pathway. Here, we propose experiments to 1.) test our model of pre-motor and striatal pathway function in juvenile birds and 2.) identify the neural loci and mechanisms by which auditory feedback promotes vocal learning (in juveniles) and maintenance of stable song (in adults). These experiments will provide new information about the functional architecture of the songbird vocal control network - this knowledge will offer new insight into the functional architecture of the analogous neural regions that control human vocal learning. 1