Midbrain Motor Coding of Vocal Behavior

所有类型的运动动作都依赖于大脑来选择和排序特定于行为的肌肉活动模式。这包括发声，这是鱼类，两栖动物，爬行动物，鸟类和哺乳动物共有的行为。这种包括人类语言在内的非凡行为回避了一个普遍的问题：控制运动的大脑区域是如何支持我们从可用行为动作菜单中进行选择的能力的？声音行为是回答这个问题的极好模型，因为它们通常是高度定型的，并且在一小部分容易量化的属性（如频率，振幅和持续时间）上存在差异。关于不同的大脑区域如何参与发声行为的表现，仍然缺乏令人惊讶的知识。中脑尤其如此，它在大脑半球和中枢模式发生器之间提供了关键联系，中枢模式发生器位于后脑和脊髓中，直接指导肌肉活动。发声鱼是产生发声能力的冠军，这种发声能力表现出快速、精确定时的声音脉冲。他们还提供了高度易于处理的模型，用于研究中脑如何控制声乐行为，由于一个良好的特点和实验可访问的声乐中央模式发生器。该项目将研究中脑在选择，排序和/或不同的声乐运动行为模式中的作用。首席研究员将继续招募来自不同背景的有才华的学生，包括代表性不足的少数民族，并在行为，神经和分子水平的分析中培养他们解决问题的能力。在那里，行为是由容易接近的大脑中心控制的，这些中心与其他脊椎动物的中心有着共同的进化和发育起源。该项目有两个目标，将使用行为，神经生理学和分子方法，以提供第一个全面的分析如何一个高种的发声鱼类的中脑有助于发声运动编码和动作选择。目的1将映射特定的中脑群体在不同的发声过程中激活，使用免疫组织化学检测立即早期基因（IEG）的表达，增加神经活动的代理，在大脑中收集发声鱼。目的1还将通过研究与兴奋性和抑制性递质的共表达来表征IEG鉴定的神经元的神经化学特征，并选择已知调节中脑依赖性发声机制的神经调质。 目标2将研究目标1中确定的中脑神经元群体在选择，测序和/或发声行为模式中的作用，方法是将神经生理学（包括单神经元记录）与药理学相结合，以诱导和调节发声运动活动。研究结果将为我们提供有关发声机制的信息，更广泛地说，将为我们提供有关所有脊椎动物群体的运动行为的信息。

All classes of motor actions depend on the brain for selecting and sequencing behavior-specific muscle activity patterns. This includes vocalization, a behavior that is shared among fishes, amphibians, reptiles, birds and mammals. This remarkable behavior that includes human speech begs the general question: How do brain regions that control movement underlie our ability to select from a menu of available behavioral actions? Vocal behaviors are excellent models for answering this question because they are often highly stereotyped and differ in a small set of easily quantified properties such as frequency, amplitude and duration. There remains an astonishing lack of knowledge of how different brain regions participate in the performance of vocal behavior. This is especially the case for the midbrain that provides a key link between the cerebral hemispheres and central pattern generators found in the hindbrain and spinal cord that directly instruct the activity of muscles. Sound producing fish are champions in the ability to generate vocalizations that exhibit rapid, precisely timed sound pulses. They also provide highly tractable models for studying how the midbrain controls vocal behavior due to a well-characterized and experimentally accessible vocal central pattern generator. The project will investigate the role of the midbrain in the selection, sequencing and/or patterning of different vocal motor behaviors. The Principal Investigator will continue to recruit a talented population of students from diverse backgrounds, including under-represented minorities, and train them in problem-solving at behavioral, neural and molecular levels of analysis.A practical way to address questions of how vocal motor systems function is to identify model systems, such as those in fish, where behavior is controlled by readily accessible brain centers that share evolutionary and developmental origins with centers in other vertebrates. This project has two aims that will use behavioral, neurophysiological and molecular methods to provide the first comprehensive analysis of how the midbrain of a highly species of vocal fish contributes to vocal motor coding and action selection. Aim 1 will map specific midbrain populations activated during different vocalizations by using immunohistochemistry to detect immediate early gene (IEG) expression, a proxy for increased neural activity, in brains collected from vocalizing fish. Aim 1 will also characterize the neurochemical signature of IEG-identified neurons by investigating co-expression with excitatory and inhibitory transmitters and select neuromodulators that are known to modulate midbrain-dependent mechanisms of vocalization. Aim 2 will then investigate the role of midbrain neuronal populations identified in Aim 1 in the selection, sequencing and/or patterning of vocal behavior by combining neurophysiology, including single neuron recording, with pharmacology to induce and modulate vocal motor activity. The results will inform us about vocal mechanisms and, more broadly, motor behaviors among all groups of vertebrates.