Evolution of Neural Circuits and their Behavioral Functions

学习复杂发音的能力只有人类、鸣禽和鹦鹉才进化出来。本项目研究控制发声的神经回路在发声学习的进化过程中是如何变化的。特别强调的是中脑的一个区域，因为该区域的功能被假设为随着发声能力从遗传编码转变为依赖学习而发生了重大变化。对该区域输入和输出的神经解剖学分析，对该区域损伤的行为影响的观察，以及中脑神经元活动的电生理检查都用于测试比较分析，然后用于重建声音控制系统的神经回路和行为功能在进化过程中如何变化。在这样做的过程中，这是第一个研究历史限制如何影响当前大脑功能的研究之一。这项研究的结果增强了我们对控制声音行为（包括人类语言）的大脑系统的理解，也提高了我们对神经系统如何在已有功能的现有电路的约束下进化以适应复杂的新行为能力的理解。这样的研究对于推进关于自然和人工学习系统如何作为经验的函数获得越来越复杂的能力的知识是很重要的。

9604299 Striedter The ability to learn complex vocalizations has evolved only in humans, songbirds, and parrots. This project investigates how the neural circuits controlling vocalization have changed during the evolution of vocal learning. Particular emphasis is placed on an area of the midbrain, as the function of this region is hypothesized to have changed significantly as the capacity for vocal behavior moves from being genetically coded to being dependent on learning. Neuroanatomical analysis of the inputs and outputs of this area, observations of the behavioral effects of damage to this area, and electrophysiological examination of the activity of midbrain neurons are all used to test comparative analysis is then used to reconstruct how neural circuitry and behavioral function of the vocal control system change during evolution. In doing so, this is one of the first studies to examine how historical constraints can influence current brain function. The results of this study enhance our understanding of the brain's systems for controlling vocal behavior, including human speech, as well as improve our understanding of how nervous systems in general evolve to accomodate complex new behavioral abilities within the constraints of preexisting circuits with preexisting functions. Such research is important in advancing knowledge about how natural and artificial learning systems acquire increasingly complex abilities as a function of experience.