DEVELOPMENTAL CHANGES IN NEURAL CIRCUITS FOR A BEHAVIOR

该项目旨在研究心脏的形态和功能变化。 一种习得行为的神经基础。斑马雀(PoePhila) 将被用作研究影响因素的动物模型 调节发育和成人脑的结构可塑性 脊椎动物前脑、神经和激素机制的相互作用 潜在的复杂习得行为的发展，以及性行为 神经形态和细胞过程的差异。1.斑马雀 学习在有限的一段时间内用于交流的声音 发展，歌曲学习和行为都由定义明确的人控制 神经回路。发声对本体感觉反馈的贡献 肌肉对歌曲学习的影响从未被评估过，尽管感觉轴突 已知来自发声器官的声音在三叉神经处终止 一条小路。我们最近发现，端脑末端的损伤- 三叉神经系统的位置干扰幼鸟的发声行为 在歌曲学习期间，但对歌曲模式的保持没有影响 被成年鸟杀死。我们将绘制出精确的轴突连接和 这个端脑核团的地形图关系 确定发声器官的传入纤维是否投射到这一区域， 如果是这样的话，他们是否有选择地在一个必要的区域终止 对于正常的声音发育来说。2.我们先前已经证明， 歌曲控制系统的主要丘脑中继器最初使 向其皮质靶核的旺盛投射；随后 靶核及其丘脑输入的回归。我们会给个人贴上标签 丘脑轴突终末在不同发育阶段的表达 确定单个终端乔木是否在扩展和退缩，如 最近在视觉系统中得到了演示，以及 这些事件的发生时间与自然发生的细胞死亡或 这个回路对发声行为的影响程度。我们会 也破坏丘脑核，以检查诱导的细胞死亡- 也就是说，我们将询问神经元是否需要传入输入 发育中和成年动物的靶核存活。3. 我们发现，生殖细胞的分裂程度要高得多。 晚期男性端脑上皮细胞多于女性 孵化后发育的各个阶段。这是第一次演示 脊椎动物大脑中神经发生的明显性别差异，并提示 发声行为背后的神经回路中的性别二态可能 通过调节神经元增殖而出现。我们将开始探索 这一引人注目的结果是通过研究性激素在细胞中的作用 端脑中的分裂。

This project is designed to study morphological and functional changes in the neural substrate for a learned behavior. Zebra finches (Poephila guttata) will be used as an animal model in which to investigate factors regulating structural plasticity in developing and adult brain, trophic interactions in vertebrate fore brain, neural and hormonal mechanisms underlying the development of a complex learned behavior, and sex differences in neural morphology and cellular processes. 1. Zebra finches learn the sounds used for communication during a restricted period of development, and song learning and behavior are controlled by well-defined neural circuits. The contribution of proprioceptive feedback from vocal muscles to song learning has never been evaluated, although sensory axons from the vocal organ are known to terminate throughout the trigeminal tract. We have recently shown that lesions of the telencephalic end- station of the trigeminal system disrupt vocal behavior in juvenile birds during song learning, but have no effect on maintenance of song patterns by adult birds. We will map out the precise axonal connections and topographic relationships of this telencephalic nucleus in order to determine if afferent fibers from the vocal organ project to this area, and if so whether they terminate selectively in a region that is necessary for normal vocal development. 2. We have previously demonstrated that the major thalamic relay of the song-control system initially makes an exuberant projection to its cortical target nucleus; subsequently both the target nucleus and its thalamic input regress. We will label individual thalamic axon terminals at different stages of development in order to determine whether single terminal arbors are expanding and regressing, as has recently been demonstrated in the visual system, and whether the timing of these events correlates with naturally-occurring cell death or the extent to which this circuit contributes to vocal behavior. We will also lesion this thalamic nucleus in order to examine induced cell death - i.e., we will ask whether afferent input is necessary for neuronal survival in the target nucleus in both developing and adult animals. 3. We have discovered that cell division is much higher in the germinal epithelium of the telencephalon in males than in females during late stages of post-hatch development. This is the first demonstration of a robust sex difference in neurogenesis in vertebrate brain, and suggests that sex dimorphisms in neural circuits underlying vocal behavior may emerge via regulation of neuronal proliferation. We will begin to explore this remarkable result by investigating the role of sex hormones on cell division in the telencephalon.