FOREBRAIN CONTROL OF HINDBRAIN VOCAL-PACEMAKER CIRCUITRY

已知所有脊椎动物纲的成员都使用发声， 生殖环境。 在鱼类和四足动物类调查， 日期（两栖动物，鸟类和哺乳动物），实验已经建立了一个 前脑在发声调节中的作用， 视前区（POA）和端脑腹侧在发声中起作用 调控 后脑运动模式生成电路， 支配发声肌肉组织也已概述了所有 脊椎动物类。然而，没有任何调查涉及这一问题 POA或其他前脑发声中心如何整合 各种各样的生殖行为调节后脑回路， 声音输出的变化 我们假设：（1）视前区（POA）和区域的 腹侧端脑影响发声行为的产生 海军学员，（2）这种前脑调节发生，部分通过， 发声运动的多巴胺和精氨酸催产素（AVT）神经支配 网络 以下数据有力地支持了这些假设 对于海军学员和密切相关的物种：1）声音活动可能是 通过电刺激POA和腹侧端脑引起。 2)后脑发声区的边界是一个密度的多巴胺能神经元 AVT免疫反应阳性纤维和终末。 3)《行动纲领》和 端脑腹侧含有大量多巴胺能细胞 体，而POA包含存在于细胞中的所有AVT-ir细胞体。 海军军官候补生的脑子 发声硬骨鱼提供了唯一的系统， 使用细胞内记录定量监测活性 技术. 重要的是，海军学员鱼的声音活动是 同形相关的神经元放电在后脑声乐 起搏器-运动神经元（PN-MN）回路。 因此， 可以在PN-MN水平直接监测发声运动输出 电路和电路的输出可以被分类为 正在产生物种典型的竞争或求偶发声。 这里描述的实验的主要目标是确定如何 前脑活动调节一个有节奏的活动， 在生理学、神经化学和解剖学水平上的运动回路。 这将是在平原鳍见习（Porichthys notatus）， 一种硬骨鱼，具有特征明显的后脑发声PN-MN回路。 我们的主要目标将通过实现四个 具体目标：因此，我们将通过测试我们的 通过实现三个具体目标的假设：（1）前脑 连接到已知的声乐电路将调查， 生物素化合物离子导入前脑、中脑和后脑 已被确定为发声运动网络的一部分的网站， 后脑发声运动输出的神经生理学评估 模式发生器 (2)发声运动回路的前脑调制 将通过多巴胺和AVT的离子电渗注射描绘到 发声运动区，结合发声的神经生理学评估 来自后脑模式发生器的运动输出 (3)多巴胺能 或声运动传入的AVT特征将被表征为： 联合逆行追踪和免疫细胞化学（ICC）， 对多巴胺和AVT的抗体进行了很好的表征。

Members of all vertebrate classes are known to use vocalizations in reproductive contexts. In fish and the tetrapod classes surveyed to date (amphibians, birds and mammals), experiments have established a role for the forebrain in the modulation of vocalizations and have shown the preoptic area (POA) and ventral telencephalon to function in vocal regulation. Hindbrain motor pattern generating circuitry which innervates the vocal musculature has also been outlined in all vertebrate classes. However, no investigations have addressed the issue of how the POA or other forebrain vocal centers which may integrate a variety of reproductive behaviors modulate hindbrain circuitry to effect a change in vocal output. We hypothesize that: (1) the preoptic area (POA) and regions of the ventral telencephalon influence the production of vocal behavior in midshipman, and (2) this forebrain regulation occurs, in part, via dopamine and arginine vasotocin (AVT) innervation of the vocal motor network. These hypotheses are strongly supported by the following data for midshipman and closely related species: 1) Vocal activity may be elicited by electrical stimulation of the POA and ventral telencephalon. 2) The hindbrain vocal region is bordered by a density of dopaminergic and AVT-immunoreactive (-ir) fibers and terminals. 3) The POA and ventral telencephalon contain a large number of dopaminergic cell bodies, while the POA contains all AVT-ir cell bodies present in the midshipman brain. Vocalizing teleost fish provide the only system in which hindbrain vocal activity has been monitored quantitatively using intracellular recording techniques. Importantly, the vocal activity of midshipman fish is isomorphically related to the neuronal firing in the hindbrain vocal pacemaker-motoneuron (PN-MN) circuit. Thus, forebrain modulation of vocal motor output may be monitored directly at the level of the PN-MN circuit and the output of the circuit may be classified as to which species-typical agonistic or courtship vocalization is being generated. The primary goal of the experiments described here is to determine how forebrain activity modulates a rhythmically-active, hindbrain vocal motor circuit at physiological, neurochemical, and anatomical levels. This will be performed in the plainfin midshipman (Porichthys notatus), a teleost fish with a well-characterized hindbrain vocal PN-MN circuit. Our primary goal will be realized through the achievement of four specific aims: Hence, we will address our primary goal by testing our hypotheses through the achievement of three specific aims: (1) Forebrain connectivity to the known vocal circuitry will be investigated by iontophoresis of biotin compounds into forebrain, midbrain and hindbrain sites which have been identified as part of the vocal motor network by neurophysiological assessment of vocal motor output from the hindbrain pattern generator. (2) Forebrain modulation of vocal motor circuitry will be delineated via iontophoretic injection of dopamine and AVT into vocal motor regions, coupled with neurophysiological assessment of vocal motor output from the hindbrain pattern generator. (3) The dopaminergic or AVT signature of vocal motor afferents will be characterized by combined retrograde tract-tracing and immunocytochemistry (ICC) using well characterized antibodies to dopamine and AVT.