COMPARATIVE STUDIES OF VOCAL CONTROL

描述（由申请人提供）：神经系统的一个基本特征是它们提供结构和功能的可塑性，使动物能够适应环境的变化。我们才刚刚开始了解大脑中自然发生的可塑性的潜在机制、局限性和行为后果，如学习。鸟类大脑中的鸣唱控制系统为解决行为神经科学的这些基本问题提供了极好的机会。环境因素的季节性变化，如光周期，对鸟类和大多数其他动物有着深远的影响。在鸣禽中，光周期的季节性变化引起性腺类固醇激素循环浓度的变化，这反过来又引起鸣唱行为以及控制鸣唱的神经内分泌系统的形态和生理属性的变化。个体之间社交线索的交换增强了繁殖季节歌曲系统的发育。本研究的目的是通过比较的方法来探讨鸟类鸣唱控制系统中季节可塑性的近似机制和行为功能。我们将确定是否季节性变化的神经元募集到歌曲核的因果关系与季节性死亡的神经元，以及激素是否发挥神经保护作用。我们将研究神经元的电生理特性如何随季节变化，以及歌曲回路的季节性增长是否依赖于活动。热带鸟类的歌声系统具有季节性可塑性，我们将测试这是否是由类固醇激素介导的。拟议研究的结果将增加我们对类固醇激素对神经系统影响的理解，类固醇激素如何用于治疗神经退行性疾病，以及成人大脑可塑性与学习之间的关系。

DESCRIPTION (provided by applicant): A fundamental feature of nervous systems is that they provide plasticity of structure and function which allows animals to adapt to changes in their environment. We are only beginning to understand the underlying mechanisms, the limitations, and the behavioral consequences, such as learning, of naturally occurring plasticity in the brain. The song control system in the avian brain provides excellent opportunities for addressing such basic issues of behavioral neuroscience. Seasonal changes of environmental factors, such as photoperiod, have a profound effect on birds and most other animals. In songbirds seasonal changes in photoperiod elicit changes in circulating concentrations of gonadal steroid hormones, which in turn cause changes in song behavior and in morphological and physiological attributes of the neuroendocrine system that controls song. The exchange of social cues between individuals enhances the growth of the song system during the breeding season. The goal of this proposal is to use a comparative approach to explore the proximate mechanisms and behavioral functions of seasonal plasticity in the avian song control system. We will determine whether seasonal changes in neuronal recruitment to song nuclei are causally related to seasonal death of neurons, and whether hormones play a neuroprotective role. We will examine how the electrophysiological properties of neurons change seasonally, and whether seasonal growth of song circuits is activity dependent. Tropical birds show seasonal plasticity of their song systems and we will test whether this is mediated by steroid hormones. The results of the proposed studies will increase our understanding of steroid hormonal influences on the nervous system, how steroid hormones can be used in the treatment of neurodegenerative diseases, and the relationship between plasticity in the adult brain and learning.