RUI: Identifying the Neural Mechanisms of Vocal Evolution

动物行为的多样性取决于产生这些行为的物种。行为是由神经系统中相互连接的神经元回路产生的，行为多样性往往源于这些回路的差异。在最近才分化的近亲物种中，产生不同行为的潜在回路可能包含相对较少的差异，导致观察到的变化。这个项目的目标是确定大脑的功能差异，这些差异导致了三种密切相关的非洲爪蛙物种之间的声音变化。常用的两种方法是：记录单个发声神经元的电信号，以及这些神经元的基因图谱。通过结合这两种互补的方法，行为差异的功能基础和导致这些差异的基因都被确定了。参与这个项目为学生提供了生理、分子和计算方法的强化训练。一个基于探究的研究模块也被纳入了首席研究员的教学中，允许来自不同背景的大量学生直接参与神经生物学研究。为了扩大里德学院以外的神经生物学培训机会，首席研究员为太平洋西北地区的神经科学教授举办了一个实验室教学研讨会。最后，首席研究员还召集了一个由神经科学家、计算机科学家和记者组成的小组，开发一个新的出版平台，以有效地传播科学进步，在这个平台上，新的发现可以定期纳入现有的“活文档”。总之，这些努力旨在加速发现和传播大脑功能的基本原理。脊椎动物的后脑包括许多神经回路，这些神经回路产生有节奏的行为，包括发声。雄性非洲爪蛙发出的求偶叫声对每个物种来说都是独一无二的，并且在时间模式上有所不同。这项研究调查了似乎控制三种物种不同发声时间模式的神经元。来自独立大脑的声神经记录显示出与醒着的青蛙相同的活动模式。来自这些“歌唱大脑”的全细胞膜片钳记录导致发现了似乎产生雄性广告呼叫的前运动神经元。由于它们在声音回路中明显的重要性，这些前运动神经元的进化变化可能是非洲爪蟾声音进化的重要驱动因素。三种非洲爪蟾的全细胞记录被用来识别与物种特定声音模式相关的细胞和网络特性。为了将行为差异的生理基础与其潜在的遗传原因联系起来，正在生成运动前核和个体运动前神经元的转录组来识别差异表达的基因。这些研究为评估声音回路中的某些特性和基因是否在进化过程中更容易被利用提供了基础。这些见解应该有助于提出关于进化规则和原则的新假设，这些假设可以在广泛的物种和行为中进行测试。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Animal behaviors are as diverse as the species that produce them. Behaviors are generated by circuits of interconnected neurons in the nervous system, and behavioral diversity often arises from differences in these circuits. In closely related species that have only recently diverged, the underlying circuits producing distinct behaviors are likely to contain relatively few differences responsible for the observed variation. The goal of this project is to identify functional differences in the brain that contribute to vocal variation between three closely related African clawed frog species. Two general approaches are used: recordings of the electrical signals of individual vocal neurons, and genetic profiling of these neurons. By combining these two complementary approaches, both the functional basis of behavioral differences and the genes responsible for these differences, are being identified. Participation in this project provides students intensive training in physiological, molecular, and computational methods. An inquiry-based research module also is being incorporated in the teaching of the lead investigator, allowing a large number of students from diverse backgrounds to directly engage in neurobiology research. To broaden access to neurobiology training beyond Reed, the lead investigator hosts a laboratory teaching workshop for neuroscience professors around the Pacific northwest. Finally, the lead investigator also convenes a panel of neuroscientists, computer scientists and journalists to develop a new publication platform for efficiently disseminating scientific progress, in which new discoveries can be regularly incorporated into existing "living documents." Together, these efforts aim to accelerate the discovery and dissemination of fundamental principles underlying brain function. The vertebrate hindbrain includes many neural circuits that generate rhythmic behaviors including vocalizations. Male African clawed frogs produce courtship calls that are unique to each species and differ in temporal patterns. This study investigates neurons that appear to control distinct temporal patterns of vocalizations across three species. Vocal nerve recordings from isolated brains reveal the same pattern of activity that can be recorded in awake, calling frogs. Whole-cell patch-clamp recordings from these 'singing brains' has led to the discovery of premotor neurons that appear to generate the male advertisement call. Because of their apparent importance in the vocal circuit, it is likely that evolutionary changes to these premotor neurons have been important drivers of Xenopus vocal evolution. Whole-cell recordings in the three Xenopus species are used to identify cellular and network properties that correlate with species-specific vocal patterns. To link the physiological bases of behavior differences to their underlying genetic causes, transcriptomes of the premotor nucleus and individual premotor neurons are being generated to identify differentially expressed genes. The studies provide the groundwork for assessing whether certain properties and genes in the vocal circuit are more readily exploited during evolution. Such insights should contribute to novel hypotheses regarding rules and principles of evolution that can be tested across a wide range of species and behaviors.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.